Add Eth1 Header Timestamp Check (#8771 )

* add time check * unit test * fix * Update beacon-chain/powchain/service.go Co-authored-by: Raul Jordan <raul@prysmaticlabs.com> Co-authored-by: terence tsao <terence@prysmaticlabs.com>
POW: remove context from log message (#8782 )
2026-01-10 05:47:59 -05:00 · 2021-04-17 13:55:41 +00:00 · 2021-04-16 19:16:36 +00:00 · 2021-04-16 10:18:59 -07:00 · 2021-04-16 16:25:28 +00:00 · 2021-04-16 08:44:36 -05:00
1672 changed files with 162293 additions and 75154 deletions
--- a/.bazelrc
+++ b/.bazelrc
@@ -5,6 +5,9 @@ test --test_verbose_timeout_warnings
 test --build_tests_only
 test --test_output=errors

+# E2E run with debug gotag
+test:e2e --define gotags=debug
+
 # Clearly indicate that coverage is enabled to disable certain nogo checks.
 coverage --define=coverage_enabled=1

@@ -14,9 +17,12 @@ test --host_force_python=PY2
 run --host_force_python=PY2

 # Networking is blocked for tests by default, add "requires-network" tag to your test if networking
-# is required within the sandbox. This flag is no longer experimental after 0.29.0.
-# Network sandboxing only works on linux.
--experimental_sandbox_default_allow_network=false
+# is required within the sandbox. Network sandboxing only works on linux.
+build --sandbox_default_allow_network=false
+
+# Stamp binaries with git information
+build --workspace_status_command=./scripts/workspace_status.sh
+build --stamp

 # Use mainnet protobufs at runtime
 run --define ssz=mainnet
@@ -33,12 +39,17 @@ build --define kafka_enabled=false
 test --define kafka_enabled=false
 run --define kafka_enabled=false

+build --define blst_disabled=false
+test --define blst_disabled=false
+run --define blst_disabled=false
+
 build:kafka_enabled --define kafka_enabled=true
 build:kafka_enabled --define gotags=kafka_enabled

+build:blst_disabled --define blst_disabled=true
+build:blst_disabled --define gotags=blst_disabled
+
 # Release flags
-build:release --workspace_status_command=./scripts/workspace_status.sh
-build:release --stamp
 build:release --compilation_mode=opt
 build:release --config=llvm

@@ -69,18 +80,13 @@ build:fuzz --copt=-fno-omit-frame-pointer
 build:fuzz --define=FUZZING_ENGINE=libfuzzer
 build:fuzz --copt=-DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 build:fuzz --linkopt -Wl,--no-as-needed
-build:fuzz --define=gc_goopts=-d=libfuzzer
+build:fuzz --define=gc_goopts=-d=libfuzzer,checkptr
 build:fuzz --run_under=//tools:fuzz_wrapper
 build:fuzz --compilation_mode=opt
+build:fuzz --define=blst_disabled=true

 test:fuzz --local_test_jobs="HOST_CPUS*.5"

-test:fuzzit --config=fuzz
-test:fuzzit --test_env=FUZZIT_API_KEY
-test:fuzzit --test_env=PRYSM_BUILD_IMAGE=gcr.io/prysmaticlabs/prysm-fuzzit:v0.11.0
-test:fuzzit --test_timeout=1200
-test:fuzzit --run_under=//tools:fuzzit_wrapper
-
 # Build binary with cgo symbolizer for debugging / profiling.
 build:cgo_symbolizer --config=llvm
 build:cgo_symbolizer --copt=-g
@@ -231,3 +237,6 @@ build:remote --remote_timeout=3600
 build:remote --experimental_remote_download_outputs=toplevel --experimental_inmemory_jdeps_files --experimental_inmemory_dotd_files

 build:remote --remote_local_fallback
+
+# Ignore GoStdLib with remote caching
+build --modify_execution_info='GoStdlib.*=+no-remote-cache'
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-3.2.0
+3.7.0
--- a/.buildkite-bazelrc
+++ b/.buildkite-bazelrc
@@ -2,25 +2,22 @@
 # across machines, developers, and workspaces.
 # 
 # This config is loaded from https://github.com/bazelbuild/bazel-toolchains/blob/master/bazelrc/latest.bazelrc
-build:remote-cache --remote_cache=grpcs://remotebuildexecution.googleapis.com
-build:remote-cache --remote_timeout=3600
-build:remote-cache --auth_enabled=true
-build:remote-cache --spawn_strategy=standalone
-build:remote-cache --strategy=Javac=standalone
-build:remote-cache --strategy=Closure=standalone
-build:remote-cache --strategy=Genrule=standalone
-
-# Build results backend.                                                        
-#build:remote-cache --bes_results_url="https://source.cloud.google.com/results/invocations/"
-#build:remote-cache --bes_backend=buildeventservice.googleapis.com               
-#build:remote-cache --bes_timeout=60s                                            
-#build:remote-cache --project_id=prysmaticlabs
+#build:remote-cache --remote_timeout=3600
+#build:remote-cache --spawn_strategy=standalone
+#build:remote-cache --strategy=Javac=standalone
+#build:remote-cache --strategy=Closure=standalone
+#build:remote-cache --strategy=Genrule=standalone

 # Prysm specific remote-cache properties.
-build:remote-cache --disk_cache=
-build:remote-cache --host_platform_remote_properties_override='properties:{name:\"cache-silo-key\" value:\"prysm\"}' 
-build:remote-cache --remote_instance_name=projects/prysmaticlabs/instances/default_instance
+#build:remote-cache --disk_cache=
 build:remote-cache --remote_download_minimal
+build:remote-cache --remote_cache=grpc://bazel-remote-cache:9092
+build:remote-cache --experimental_remote_downloader=grpc://bazel-remote-cache:9092
+build:remote-cache --remote_local_fallback
+# Enforce stricter environment rules, which eliminates some non-hermetic
+# behavior and therefore improves both the remote cache hit rate and the
+# correctness and repeatability of the build.
+build:remote-cache --incompatible_strict_action_env=true

 # Import workspace options.
 import %workspace%/.bazelrc
@@ -44,16 +41,5 @@ build --flaky_test_attempts=5
 # Disabled race detection due to unstable test results under constrained environment build kite
 # build --features=race

-# Enable kafka for CI tests only.
-test --config=kafka_enabled
-
-build --bes_backend=grpcs://builds.prylabs.net:1985
-build --bes_results_url=https://builds.prylabs.net/invocation/
-
 # Disable flaky test detection for fuzzing.
 test:fuzz --flaky_test_attempts=1
-
-# Expose test environment variables in CI
-test:fuzzit --test_env=GITHUB_REF
-test:fuzzit --test_env=GITHUB_SHA
-test:fuzzit --test_env=DOCKER_HOST
--- a/.codecov.yml
+++ b/.codecov.yml
@@ -30,4 +30,4 @@ comment:

 ignore:
  - "**/*.pb.go"
-  - "**/*_mock.go"
+  - "**/testing/**/*"
--- a/.deepsource.toml
+++ b/.deepsource.toml
@@ -0,0 +1,26 @@
+version = 1
+
+exclude_patterns = [
+  "tools/analyzers/**",
+  "validator/keymanager/remote/keymanager_test.go",
+  "validator/web/site_data.go"
+]
+
+[[analyzers]]
+name = "go"
+enabled = true
+
+[analyzers.meta]
+import_paths = ["github.com/prysmaticlabs/prysm"]
+
+[[analyzers]]
+name = "test-coverage"
+enabled = true
+
+[[analyzers]]
+name = "shell"
+enabled = true
+
+[[analyzers]]
+name = "secrets"
+enabled = true
--- a/.github/PULL_REQUEST_TEMPLATE.md
+++ b/.github/PULL_REQUEST_TEMPLATE.md
@@ -1,8 +1,8 @@
 <!-- Thanks for sending a PR! Before submitting:

-1. If this is your first PR, please read CONTRIBUTING.md and sign the CLA
-   first. We cannot review code without a signed CLA.
-2. Please file an issue *first*. All features and most bug fixes should have
+1. If this is your first PR, check out our contribution guide here https://docs.prylabs.network/docs/contribute/contribution-guidelines
+   You will then need to sign our Contributor License Agreement (CLA), which will show up as a comment from a bot in this pull request after you open it. We cannot review code without a signed CLA.
+2. Please file an associated tracking issue if this pull request is non-trivial and requires context for our team to understand. All features and most bug fixes should have
   an associated issue with a design discussed and decided upon. Small bug
   fixes and documentation improvements don't need issues.
 3. New features and bug fixes must have tests. Documentation may need to
--- a/.github/workflows/go.yml
+++ b/.github/workflows/go.yml
@@ -43,6 +43,7 @@ jobs:
          go get -v -t -d ./...

      - name: Build
+        # Use blst tag to allow go and bazel builds for blst.
        run: go build -v ./...

 # Tests run via Bazel for now...
--- a/.gitignore
+++ b/.gitignore
@@ -29,3 +29,10 @@ password.txt

 # Dist files
 dist
+
+# libfuzzer
+oom-*
+crash-*
+
+# deepsource cli
+bin
--- a/.policy.yml
+++ b/.policy.yml
@@ -0,0 +1,91 @@
+policy:
+  approval:
+    - or:
+        - only test files are changed
+        - only proto files are changed
+        - touches consensus critical code
+        - touches sync/blockchain/p2p code
+        - large line count
+        - is critical priority
+approval_rules:
+  - name: only test files are changed
+    if:
+      only_changed_files:
+        paths:
+          - "*_test.go"
+          - "*.bazel"
+    options:
+      ignore_commits_by:
+        users: ["bulldozer[bot]"]
+    requires:
+      count: 1
+      teams:
+        - "prysmaticlabs/core-team"
+  - name: only proto files are changed
+    if:
+      only_changed_files:
+        paths:
+          - "*pb.go"
+          - "*pb.gw.go"
+          - "*.bazel"
+    options:
+      ignore_commits_by:
+        users: ["bulldozer[bot]"]
+    requires:
+      count: 1
+      teams:
+        - "prysmaticlabs/core-team"
+  - name: touches consensus critical code
+    if:
+      only_changed_files:
+        paths:
+          - "beacon-chain/core/*"
+          - "beacon-chain/state/*"
+    options:
+      ignore_commits_by:
+        users: ["bulldozer[bot]"]
+    requires:
+      count: 2
+      teams:
+        - "prysmaticlabs/core-team"
+  - name: touches sync/blockchain/p2p code
+    if:
+      only_changed_files:
+        paths:
+          - "beacon-chain/blockchain/*"
+          - "beacon-chain/sync/*"
+          - "beacon-chain/p2p/*"
+    options:
+      ignore_commits_by:
+        users: ["bulldozer[bot]"]
+    requires:
+      count: 2
+      teams:
+        - "prysmaticlabs/core-team"
+  - name: large line count
+    if:
+      modified_lines:
+        total: "> 1000"
+      changed_files:
+        ignore:
+          - "*pb.go"
+          - "*pb.gw.go"
+          - "*.bazel"
+    options:
+      ignore_commits_by:
+        users: ["bulldozer[bot]"]
+    requires:
+      count: 2
+      teams:
+        - "prysmaticlabs/core-team"
+  - name: is critical priority
+    if:
+      has_labels:
+        - "Priority: Critical"
+    options:
+      ignore_commits_by:
+        users: ["bulldozer[bot]"]
+    requires:
+      count: 3
+      teams:
+        - "prysmaticlabs/core-team"
--- a/.well-known/security.pub
+++ b/.well-known/security.pub
@@ -0,0 +1,218 @@
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+-----END PGP PUBLIC KEY BLOCK-----
--- a/.well-known/security.txt
+++ b/.well-known/security.txt
@@ -3,24 +3,23 @@ Hash: SHA512

 Contact: mailto:security@prysmaticlabs.com
 Encryption: openpgp4fpr:0AE0051D647BA3C1A917AF4072E33E4DF1A5036E
-Encryption: openpgp4fpr:341396BAFACC28C5082327F889725027FC8EC0D4
-Encryption: openpgp4fpr:FEE44615A19049DF0CA0C2735E2B7E5734DFADCB
+Encryption: openpgp4fpr:CD08DE68C60B82D3EE2A3F7D95452A701810FEDB
+Encryption: openpgp4fpr:317D6E91058F8F3C2303BA7756313E44581297A6
 Preferred-Languages: en
 Canonical: https://github.com/prysmaticlabs/prysm/tree/master/.well-known/security.txt
-
 -----BEGIN PGP SIGNATURE-----

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+fX0R9g/HMgrwNte/d0mwim5lJ2Plgv60Bh4grJqwZJeWbU0zi1U=
+=uW+X
 -----END PGP SIGNATURE-----
--- a/BUILD.bazel
+++ b/BUILD.bazel
@@ -104,10 +104,15 @@ nogo(
        "@org_golang_x_tools//go/analysis/passes/inspect:go_tool_library",
        "@org_golang_x_tools//go/analysis/passes/asmdecl:go_tool_library",
        "//tools/analyzers/maligned:go_tool_library",
-        "//tools/analyzers/roughtime:go_tool_library",
        "//tools/analyzers/cryptorand:go_tool_library",
        "//tools/analyzers/errcheck:go_tool_library",
        "//tools/analyzers/featureconfig:go_tool_library",
+        "//tools/analyzers/comparesame:go_tool_library",
+        "//tools/analyzers/shadowpredecl:go_tool_library",
+        "//tools/analyzers/nop:go_tool_library",
+        "//tools/analyzers/slicedirect:go_tool_library",
+        "//tools/analyzers/ineffassign:go_tool_library",
+        "//tools/analyzers/properpermissions:go_tool_library",
    ] + select({
        # nogo checks that fail with coverage enabled.
        ":coverage_enabled": [],
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -4,7 +4,7 @@ Note: The latest and most up to date documenation can be found on our [docs port

 Excited by our work and want to get involved in building out our sharding releases? Or maybe you haven't learned as much about the Ethereum protocol but are a savvy developer? 

-You can explore our [Open Issues](https://github.com/prysmaticlabs/prysm/issues) in-the works for our different releases. Feel free to fork our repo and start creating PR’s after assigning yourself to an issue of interest. We are always chatting on [Discord](https://discord.gg/che9auJ) or [Gitter](https://gitter.im/prysmaticlabs/geth-sharding) drop us a line there if you want to get more involved or have any questions on our implementation!
+You can explore our [Open Issues](https://github.com/prysmaticlabs/prysm/issues) in-the works for our different releases. Feel free to fork our repo and start creating PR’s after assigning yourself to an issue of interest. We are always chatting on [Discord](https://discord.gg/CTYGPUJ) drop us a line there if you want to get more involved or have any questions on our implementation!

 ## Contribution Steps

@@ -62,12 +62,6 @@ Changes that only affect a single file can be tested with
 $ go test <file_you_are_working_on>
 ```

-Changes that affect multiple files can be tested with ...
-
-```
-$ golangci-lint run && bazel test //...
-```
-
 **10. Stage the file or files that you want to commit.**

 ```
@@ -181,7 +175,7 @@ We consider two types of contributions to our repo and categorize them as follow

 ### Part-Time Contributors

-Anyone can become a part-time contributor and help out on implementing sharding. The responsibilities of a part-time contributor include:
+Anyone can become a part-time contributor and help out on implementing eth2. The responsibilities of a part-time contributor include:

 -   Engaging in Gitter conversations, asking the questions on how to begin contributing to the project
 -   Opening up github issues to express interest in code to implement
@@ -192,8 +186,6 @@ Anyone can become a part-time contributor and help out on implementing sharding.
 -   Follow up on open PRs
    -   Have an estimated timeframe to completion and let the core contributors know if a PR will take longer than expected

-We do not expect all part-time contributors to be experts on all the latest sharding documentation, but all contributors should at least be familiarized with our sharding [README.md](https://github.com/prysmaticlabs/prysm/blob/master/validator/README.md) and have gone through the required Ethereum readings as posted on our [READINGS.md](https://github.com/prysmaticlabs/prysm/blob/master/docs/READINGS.md) document.
-
 ### Core Contributors

 Core contributors are remote contractors of Prysmatic Labs, LLC. and are considered critical team members of our organization. Core devs have all of the responsibilities of part-time contributors plus the majority of the following:
--- a/DEPENDENCIES.md
+++ b/DEPENDENCIES.md
@@ -61,9 +61,20 @@ Example:

 ```bash
 go get github.com/prysmaticlabs/example@v1.2.3
-bazel run //:gazelle -- update-repos -from_file=go.mod -to_macro=deps.bzl%prysm_deps
+bazel run //:gazelle -- update-repos -from_file=go.mod -to_macro=deps.bzl%prysm_deps -prune=true
 ```

 The deps.bzl file should have been updated with the dependency and any transitive dependencies. 

 Do NOT add new `go_repository` to the WORKSPACE file. All dependencies should live in deps.bzl.
+
+## Running tests
+
+To enable conditional compilation and custom configuration for tests (where compiled code has more 
+debug info, while not being completely optimized), we rely on Go's build tags/constraints mechanism 
+(see official docs on [build constraints](https://golang.org/pkg/go/build/#hdr-Build_Constraints)). 
+Therefore, whenever using `go test`, do not forget to pass in extra build tag, eg:
+
+```bash
+go test ./beacon-chain/sync/initial-sync -tags develop 
+```
--- a/README.md
+++ b/README.md
@@ -1,21 +1,35 @@
-# Prysm: An Ethereum 2.0 Client Written in Go
+# Prysm: An Ethereum 2.0 Implementation Written in Go

 [![Build status](https://badge.buildkite.com/b555891daf3614bae4284dcf365b2340cefc0089839526f096.svg?branch=master)](https://buildkite.com/prysmatic-labs/prysm)
-[![fuzzit](https://app.fuzzit.dev/badge?org_id=prysmaticlabs-gh)](https://app.fuzzit.dev/orgs/prysmaticlabs-gh/dashboard)
-[![ETH2.0_Spec_Version 0.12.1](https://img.shields.io/badge/ETH2.0%20Spec%20Version-v0.12.1-blue.svg)](https://github.com/ethereum/eth2.0-specs/tree/v0.12.1)
-[![Discord](https://user-images.githubusercontent.com/7288322/34471967-1df7808a-efbb-11e7-9088-ed0b04151291.png)](https://discord.gg/KSA7rPr)
-[![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/prysmaticlabs/geth-sharding?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge)
+[![Go Report Card](https://goreportcard.com/badge/github.com/prysmaticlabs/prysm)](https://goreportcard.com/report/github.com/prysmaticlabs/prysm)
+[![ETH2.0_Spec_Version 1.0.0](https://img.shields.io/badge/ETH2.0%20Spec%20Version-v1.0.0-blue.svg)](https://github.com/ethereum/eth2.0-specs/tree/v1.0.0)
+[![Discord](https://user-images.githubusercontent.com/7288322/34471967-1df7808a-efbb-11e7-9088-ed0b04151291.png)](https://discord.gg/CTYGPUJ)

-This is the core repository for Prysm, a [Golang](https://golang.org/) implementation of the Ethereum 2.0 client specifications developed by [Prysmatic Labs](https://prysmaticlabs.com).
+This is the core repository for Prysm, a [Golang](https://golang.org/) implementation of the [Ethereum 2.0](https://ethereum.org/en/eth2/) specification, developed by [Prysmatic Labs](https://prysmaticlabs.com). See the [Changelog](https://github.com/prysmaticlabs/prysm/releases) for details of the latest releases and upcoming breaking changes.

 ### Getting Started
-A detailed set of installation and usage instructions as well as breakdowns of each individual component are available in the [official documentation portal](https://docs.prylabs.network). If you still have questions, feel free to stop by either our [Discord](https://discord.gg/KSA7rPr) or [Gitter](https://gitter.im/prysmaticlabs/geth-sharding?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge) and a member of the team or our community will be happy to assist you.

-### Come join the testnet!
-Participation is now open to the public for our Ethereum 2.0 phase 0 testnet release. Visit [prylabs.net](https://prylabs.net) for more information on the project or to sign up as a validator on the network. You can visualize the nodes in the network on [eth2stats.io](https://eth2stats.io), explore validator rewards/penalties via Bitfly's block explorer: [beaconcha.in](https://beaconcha.in), and follow the latest blocks added to the chain on [Etherscan](https://beacon.etherscan.io).
+A detailed set of installation and usage instructions as well as breakdowns of each individual component are available in the [official documentation portal](https://docs.prylabs.network). If you still have questions, feel free to stop by our [Discord](https://discord.gg/CTYGPUJ).
+
+### Staking on Mainnet
+
+To participate in staking, you can join the [official eth2 launchpad](https://launchpad.ethereum.org). The launchpad is the only recommended way to become a validator on mainnet. You can explore validator rewards/penalties via Bitfly's block explorer: [beaconcha.in](https://beaconcha.in), and follow the latest blocks added to the chain on [beaconscan](https://beaconscan.com).
+

 ## Contributing
+### Branches
+Prysm maintains two permanent branches:
+
+* [master](https://github.com/prysmaticlabs/prysm/tree/master): This points to the latest stable release. It is ideal for most users.
+* [develop](https://github.com/prysmaticlabs/prysm/tree/develop): This is used for development, it contains the latest PRs. Developers should base their PRs on this branch.
+
+### Guide
 Want to get involved? Check out our [Contribution Guide](https://docs.prylabs.network/docs/contribute/contribution-guidelines/) to learn more!

 ## License
+
 [GNU General Public License v3.0](https://www.gnu.org/licenses/gpl-3.0.en.html)
+
+## Legal Disclaimer
+
+[Terms of Use](/TERMS_OF_SERVICE.md)
--- a/TERMS_OF_SERVICE.md
+++ b/TERMS_OF_SERVICE.md
@@ -0,0 +1,45 @@
+## Terms of Use
+
+Effective as of Oct 14, 2020
+
+By downloading, accessing or using the Prysm implementation (“Prysm”), you (referenced herein as “you” or the “user”) certify that you have read and agreed to the terms and conditions below (the “Terms”) which form a binding contract between you and Prysmatic Labs (referenced herein as “we” or “us”). If you do not agree to the Terms, do not download or use Prysm.
+
+### About Prysm
+Prysm is a client implementation for Ethereum 2.0 Phase 0 protocol for a proof-of-stake blockchain. To participate in the network, a user must send ETH from the Eth1.0 chain into a validator deposit contract, which will queue in the user as a validator in the system. Validators participate in proposing and voting on blocks in the protocol, and the network applies rewards/penalties based on their behavior. A detailed set of installation and usage instructions as well as breakdowns of each individual component are available in the official documentation portal, however, we do not warrant the accuracy, completeness or usefulness of this documentation. Any reliance you place on such information is strictly at your own risk.
+
+### Licensing Terms
+Prysm is a fully open-source software program licensed pursuant to the GNU General Public License v3.0.
+
+The Prysmatic Labs name, the term “Prysm” and all related names, logos, product and service names, designs and slogans are trademarks of Prysmatic Labs or its affiliates and/or licensors. You must not use such marks without our prior written permission.
+
+### Risks of Operating Prysm
+The use of Prysm and acting as a validator on the Ethereum 2.0 network can lead to loss of money. Ethereum is still an experimental system and ETH remains a risky investment. You alone are responsible for your actions on Prysm including the security of your ETH and meeting any applicable minimum system requirements.
+
+Use of Prysm and the ability to receive rewards or penalties may be affected at any time by mistakes made by the user or other users, software problems such as bugs, errors, incorrectly constructed transactions, unsafe cryptographic libraries or malware affecting the network, technical failures in the hardware of a user, security problems experienced by a user and/or actions or inactions of third parties and/or events experienced by third parties, among other risks. We cannot and do not guarantee that any user of Prysm will make money, that the Prysm network will operate in accordance with the documentation or that transactions will be effective or secure.
+
+We make no claims that Prysm is appropriate or permitted for use in any specific jurisdiction. Access to Prysm may not be legal by certain persons or in certain jurisdictions or countries. If you access Prysm, you do so on your own initiative and are responsible for compliance with local laws.
+
+Some Internet plans will charge an additional amount for any excess upload bandwidth used that isn’t included in the plan and may terminate your connection without warning because of overuse. We advise that you check whether your Internet connection is subjected to such limitations and monitor your bandwidth use so that you can stop Prysm before you reach your upload limit.
+
+### Warranty Disclaimer
+PRYSM IS PROVIDED ON AN “AS-IS” BASIS AND MAY INCLUDE ERRORS, OMISSIONS, OR OTHER INACCURACIES. PRYSMATIC LABS AND ITS CONTRIBUTORS MAKE NO REPRESENTATIONS OR WARRANTIES ABOUT PRYSM FOR ANY PURPOSE, AND HEREBY EXPRESSLY DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING, WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT OR ANY OTHER IMPLIED WARRANTY UNDER THE UNIFORM COMPUTER INFORMATION TRANSACTIONS ACT AS ENACTED BY ANY STATE. WE ALSO MAKE NO REPRESENTATIONS OR WARRANTIES THAT PRYSM WILL OPERATE ERROR-FREE, UNINTERRUPTED, OR IN A MANNER THAT WILL MEET YOUR REQUIREMENTS AND/OR NEEDS. THEREFORE, YOU ASSUME THE ENTIRE RISK REGARDING THE QUALITY AND/OR PERFORMANCE OF PRYSM AND ANY TRANSACTIONS ENTERED INTO THEREON.
+
+### Limitation of Liability
+In no event will Prysmatic Labs or any of its contributors be liable, whether in contract, warranty, tort (including negligence, whether active, passive or imputed), product liability, strict liability or other theory, breach of statutory duty or otherwise arising out of, or in connection with, your use of Prysm, for any direct, indirect, incidental, special or consequential damages (including any loss of profits or data, business interruption or other pecuniary loss, or damage, loss or other compromise of data, in each case whether direct, indirect, incidental, special or consequential) arising out of use Prysm, even if we or other users have been advised of the possibility of such damages. The foregoing limitations and disclaimers shall apply to the maximum extent permitted by applicable law, even if any remedy fails of its essential purpose. You acknowledge and agree that the limitations of liability afforded us hereunder constitute a material and actual inducement and condition to entering into these Terms, and are reasonable, fair and equitable in scope to protect our legitimate interests in light of the fact that we are not receiving consideration from you for providing Prysm.
+
+### Indemnification
+To the maximum extent permitted by law, you will defend, indemnify and hold Prysmatic Labs and its contributors harmless from and against any and all claims, actions, suits, investigations, or proceedings by any third party (including any party or purported party to or beneficiary or purported beneficiary of any transaction on Prysm), as well as any and all losses, liabilities,
+damages, costs, and expenses (including reasonable attorneys’ fees) arising out of, accruing from, or in any way related to (i) your breach of the terms of this Agreement, (ii) any transaction, or the failure to occur of any transaction on Prysm, and (iii) your negligence, fraud, or willful misconduct.
+
+### Compliance with Laws and Tax Obligations
+Your use of Prysm is subject to all applicable laws of any governmental authority, including, without limitation, federal, state and foreign securities laws, tax laws, tariff and trade laws, ordinances, judgments, decrees, injunctions, writs and orders or like actions of any governmental authority and rules, regulations, orders, interpretations, licenses, and permits of any federal,
+regional, state, county, municipal or other governmental authority and you agree to comply with all such laws in your use of Prysm. The users of Prysm are solely responsible to determinate what, if any, taxes apply to their ETH transactions. The owners of, or contributors to, Prysm are not responsible for determining the taxes that apply to ETH transactions.
+
+### Miscellaneous
+These Terms will be construed and enforced in accordance with the laws of the state of Illinois as applied to agreements entered into and completely performed in Illinois. You agree to the personal jurisdiction by and venue in Illinois and waive any objection to such jurisdiction or venue.
+
+We reserve the right to revise these Terms, and your rights and obligations are at all times subject to the then-current Terms provided on Prysm. Your continued use of Prysm constitutes acceptance of such revised Terms.
+
+These Terms constitute the entire agreement between you and Prysmatic Labs regarding use of Prysm and will supersede all prior agreements whether, written or oral. No usage of trade or other regular practice or method of dealing between the parties will be used to modify, interpret, supplement, or alter the terms of these Terms.
+
+If any portion of these Terms is held invalid or unenforceable, such invalidity or enforceability will not affect the other provisions of these Terms, which will remain in full force and effect, and the invalid or unenforceable portion will be given effect to the greatest extent possible. The failure of a party to require performance of any provision will not affect that party’s right to require performance at any time thereafter, nor will a waiver of any breach or default of these Terms or any provision of these Terms constitute a waiver of any subsequent breach or default or a waiver of the provision itself.
--- a/TESTNET.md
+++ b/TESTNET.md
@@ -1,43 +0,0 @@
-# Testnet 
-
-The Prysmatic Labs test network is available for anyone to join. The easiest way to participate is by joining through the website, https://prylabs.net.
-
-## Interop
-
-For developers looking to connect a client other than Prysm to the test network, here is the relevant information for compatability. 
-
-
-**Spec version** - [v0.8.3](https://github.com/ethereum/eth2.0-specs/tree/v0.8.3)
-
-**ETH 1 Deposit Contract Address** - See https://prylabs.net/contract. This contract is deployed on the [goerli](https://goerli.net/) network. 
-
-**Genesis time** - The ETH1 block time in which the 64th deposit to start ETH2 was included. This is NOT midnight of the next day as required by spec.
-
-### ETH 2 Configuration
-
-Use the [minimal config](https://github.com/ethereum/eth2.0-specs/blob/v0.8.3/configs/minimal.yaml) with the following changes.
-
-| field | value |
-|-------|-------|
-| MIN_DEPOSIT_AMOUNT | 100 |
-| MAX_EFFECTIVE_BALANCE | 3.2 * 1e9 |
-| EJECTION_BALANCE | 1.6 * 1e9 |
-| EFFECTIVE_BALANCE_INCREMENT | 0.1 * 1e9 |
-| ETH1_FOLLOW_DISTANCE | 16 | 
-| GENESIS_FORK_VERSION | See [latest code](https://github.com/prysmaticlabs/prysm/blob/master/shared/params/config.go#L236) |
-
-These parameters reduce the minimal config to 1/10 of the required ETH.
-
-We have a genesis.ssz file available for download [here](https://prysmaticlabs.com/uploads/genesis.ssz)
-
-### Connecting to the network
-
-We have a libp2p bootstrap node available at `/dns4/prylabs.net/tcp/30001/p2p/16Uiu2HAm7Qwe19vz9WzD2Mxn7fXd1vgHHp4iccuyq7TxwRXoAGfc`.
-
-Some of the Prysmatic Labs hosted nodes are behind a libp2p relay, so your libp2p implementation protocol should understand this functionality.
-
-### Other
-
-Undoubtably, you will have bugs. Reach out to us on [Discord](https://discord.gg/KSA7rPr) and be sure to capture issues on Github at https://github.com/prysmaticlabs/prysm/issues. 
-
-If you have instructions for you client, we would love to attempt this on your behalf. Kindly send over the instructions via github issue, PR, email to team@prysmaticlabs.com, or discord.
--- a/1
+++ b/1
@@ -1 +0,0 @@
-0.2.0
--- a/107
+++ b/107
@@ -5,19 +5,19 @@ load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")

 http_archive(
    name = "bazel_toolchains",
-    sha256 = "144290c4166bd67e76a54f96cd504ed86416ca3ca82030282760f0823c10be48",
-    strip_prefix = "bazel-toolchains-3.1.1",
+    sha256 = "8e0633dfb59f704594f19ae996a35650747adc621ada5e8b9fb588f808c89cb0",
+    strip_prefix = "bazel-toolchains-3.7.0",
    urls = [
-        "https://github.com/bazelbuild/bazel-toolchains/releases/download/3.1.1/bazel-toolchains-3.1.1.tar.gz",
-        "https://mirror.bazel.build/github.com/bazelbuild/bazel-toolchains/archive/3.1.1.tar.gz",
+        "https://mirror.bazel.build/github.com/bazelbuild/bazel-toolchains/releases/download/3.7.0/bazel-toolchains-3.7.0.tar.gz",
+        "https://github.com/bazelbuild/bazel-toolchains/releases/download/3.7.0/bazel-toolchains-3.7.0.tar.gz",
    ],
 )

 http_archive(
    name = "com_grail_bazel_toolchain",
-    sha256 = "0bec89e35d8a141c87f28cfc506d6d344785c8eb2ff3a453140a1fe972ada79d",
-    strip_prefix = "bazel-toolchain-77a87103145f86f03f90475d19c2c8854398a444",
-    urls = ["https://github.com/grailbio/bazel-toolchain/archive/77a87103145f86f03f90475d19c2c8854398a444.tar.gz"],
+    sha256 = "b924b102adc0c3368d38a19bd971cb4fa75362a27bc363d0084b90ca6877d3f0",
+    strip_prefix = "bazel-toolchain-0.5.7",
+    urls = ["https://github.com/grailbio/bazel-toolchain/archive/0.5.7.tar.gz"],
 )

 load("@com_grail_bazel_toolchain//toolchain:deps.bzl", "bazel_toolchain_dependencies")
@@ -28,7 +28,7 @@ load("@com_grail_bazel_toolchain//toolchain:rules.bzl", "llvm_toolchain")

 llvm_toolchain(
    name = "llvm_toolchain",
-    llvm_version = "9.0.0",
+    llvm_version = "10.0.0",
 )

 load("@llvm_toolchain//:toolchains.bzl", "llvm_register_toolchains")
@@ -47,10 +47,10 @@ load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

 http_archive(
    name = "bazel_skylib",
-    sha256 = "97e70364e9249702246c0e9444bccdc4b847bed1eb03c5a3ece4f83dfe6abc44",
+    sha256 = "1c531376ac7e5a180e0237938a2536de0c54d93f5c278634818e0efc952dd56c",
    urls = [
-        "https://mirror.bazel.build/github.com/bazelbuild/bazel-skylib/releases/download/1.0.2/bazel-skylib-1.0.2.tar.gz",
-        "https://github.com/bazelbuild/bazel-skylib/releases/download/1.0.2/bazel-skylib-1.0.2.tar.gz",
+        "https://github.com/bazelbuild/bazel-skylib/releases/download/1.0.3/bazel-skylib-1.0.3.tar.gz",
+        "https://mirror.bazel.build/github.com/bazelbuild/bazel-skylib/releases/download/1.0.3/bazel-skylib-1.0.3.tar.gz",
    ],
 )

@@ -60,10 +60,10 @@ bazel_skylib_workspace()

 http_archive(
    name = "bazel_gazelle",
-    sha256 = "d8c45ee70ec39a57e7a05e5027c32b1576cc7f16d9dd37135b0eddde45cf1b10",
+    sha256 = "62ca106be173579c0a167deb23358fdfe71ffa1e4cfdddf5582af26520f1c66f",
    urls = [
-        "https://storage.googleapis.com/bazel-mirror/github.com/bazelbuild/bazel-gazelle/releases/download/v0.20.0/bazel-gazelle-v0.20.0.tar.gz",
-        "https://github.com/bazelbuild/bazel-gazelle/releases/download/v0.20.0/bazel-gazelle-v0.20.0.tar.gz",
+        "https://mirror.bazel.build/github.com/bazelbuild/bazel-gazelle/releases/download/v0.23.0/bazel-gazelle-v0.23.0.tar.gz",
+        "https://github.com/bazelbuild/bazel-gazelle/releases/download/v0.23.0/bazel-gazelle-v0.23.0.tar.gz",
    ],
 )

@@ -76,9 +76,9 @@ http_archive(

 http_archive(
    name = "io_bazel_rules_docker",
-    sha256 = "dc97fccceacd4c6be14e800b2a00693d5e8d07f69ee187babfd04a80a9f8e250",
-    strip_prefix = "rules_docker-0.14.1",
-    url = "https://github.com/bazelbuild/rules_docker/archive/v0.14.1.tar.gz",
+    sha256 = "1286175a94c0b1335efe1d75d22ea06e89742557d3fac2a0366f242a6eac6f5a",
+    strip_prefix = "rules_docker-ba4310833230294fa69b7d6ea1787ac684631a7d",
+    urls = ["https://github.com/bazelbuild/rules_docker/archive/ba4310833230294fa69b7d6ea1787ac684631a7d.tar.gz"],
 )

 http_archive(
@@ -89,10 +89,10 @@ http_archive(
        # nogo check fails for certain third_party dependencies.
        "//third_party:io_bazel_rules_go.patch",
    ],
-    sha256 = "7b9bbe3ea1fccb46dcfa6c3f3e29ba7ec740d8733370e21cdc8937467b4a4349",
+    sha256 = "7c10271940c6bce577d51a075ae77728964db285dac0a46614a7934dc34303e6",
    urls = [
-        "https://mirror.bazel.build/github.com/bazelbuild/rules_go/releases/download/v0.22.4/rules_go-v0.22.4.tar.gz",
-        "https://github.com/bazelbuild/rules_go/releases/download/v0.22.4/rules_go-v0.22.4.tar.gz",
+        "https://mirror.bazel.build/github.com/bazelbuild/rules_go/releases/download/v0.26.0/rules_go-v0.26.0.tar.gz",
+        "https://github.com/bazelbuild/rules_go/releases/download/v0.26.0/rules_go-v0.26.0.tar.gz",
    ],
 )

@@ -100,14 +100,14 @@ http_archive(
 # https://github.com/gogo/protobuf/pull/582 is merged.
 git_repository(
    name = "com_github_gogo_protobuf",
-    commit = "5628607bb4c51c3157aacc3a50f0ab707582b805",
+    commit = "b03c65ea87cdc3521ede29f62fe3ce239267c1bc",
    patch_args = ["-p1"],
    patches = [
        "@io_bazel_rules_go//third_party:com_github_gogo_protobuf-gazelle.patch",
        "//third_party:com_github_gogo_protobuf-equal.patch",
    ],
    remote = "https://github.com/gogo/protobuf",
-    shallow_since = "1571033717 +0200",
+    shallow_since = "1610265707 +0000",
    # gazelle args: -go_prefix github.com/gogo/protobuf -proto legacy
 )

@@ -139,9 +139,9 @@ load(

 container_pull(
    name = "alpine_cc_linux_amd64",
-    digest = "sha256:3f7f4dfcb6dceac3a902f36609cc232262e49f5656a6dc4bb3da89e35fecc8a5",
+    digest = "sha256:752aa0c9a88461ffc50c5267bb7497ef03a303e38b2c8f7f2ded9bebe5f1f00e",
    registry = "index.docker.io",
-    repository = "fasibio/alpine-libgcc",
+    repository = "pinglamb/alpine-glibc",
 )

 container_pull(
@@ -155,12 +155,19 @@ load("@io_bazel_rules_go//go:deps.bzl", "go_register_toolchains", "go_rules_depe

 go_rules_dependencies()

-go_register_toolchains(nogo = "@//:nogo")
+go_register_toolchains(
+    go_version = "1.16",
+    nogo = "@//:nogo",
+)

 load("@bazel_gazelle//:deps.bzl", "gazelle_dependencies")

 gazelle_dependencies()

+load("@io_bazel_rules_go//extras:embed_data_deps.bzl", "go_embed_data_dependencies")
+
+go_embed_data_dependencies()
+
 load("@com_github_atlassian_bazel_tools//gometalinter:deps.bzl", "gometalinter_dependencies")

 gometalinter_dependencies()
@@ -203,6 +210,21 @@ http_archive(
    url = "https://github.com/kubernetes/repo-infra/archive/6537f2101fb432b679f3d103ee729dd8ac5d30a0.tar.gz",
 )

+http_archive(
+    name = "eip3076_spec_tests",
+    build_file_content = """
+filegroup(
+    name = "test_data",
+    srcs = glob([
+        "**/*.json",
+    ]),
+    visibility = ["//visibility:public"],
+)
+    """,
+    sha256 = "91434d5fd5e1c6eb7b0174fed2afe25e09bddf00e1e4c431db931b2cee4e7773",
+    url = "https://github.com/eth2-clients/slashing-protection-interchange-tests/archive/b8413ca42dc92308019d0d4db52c87e9e125c4e9.tar.gz",
+)
+
 http_archive(
    name = "eth2_spec_tests_general",
    build_file_content = """
@@ -215,8 +237,8 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "678c50336ce39bef19b2a0dc69e20a7bda37a673ae07dc0577386e9876e0a525",
-    url = "https://github.com/ethereum/eth2.0-spec-tests/releases/download/v0.12.1/general.tar.gz",
+    sha256 = "ef5396e4b13995da9776eeb5ae346a2de90970c28da3c4f0dcaa4ab9f0ad1f93",
+    url = "https://github.com/ethereum/eth2.0-spec-tests/releases/download/v1.0.0/general.tar.gz",
 )

 http_archive(
@@ -231,8 +253,8 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "d0ce95a3ca0d30df24f96a1b5cfad1f7e6fcc07ad84ca221d92480add051af3e",
-    url = "https://github.com/ethereum/eth2.0-spec-tests/releases/download/v0.12.1/minimal.tar.gz",
+    sha256 = "170551b441e7d54b73248372ad9ce8cb6c148810b5f1364637117a63f4f1c085",
+    url = "https://github.com/ethereum/eth2.0-spec-tests/releases/download/v1.0.0/minimal.tar.gz",
 )

 http_archive(
@@ -247,8 +269,8 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "1dfa1ae6822912508dbf6d1fe7608169372daa3ad1e53a3ed0867cb2d6e0ccb0",
-    url = "https://github.com/ethereum/eth2.0-spec-tests/releases/download/v0.12.1/mainnet.tar.gz",
+    sha256 = "b541a9979b4703fa5ee5d2182b0b5313c38efc54ae7eaec2eef793230a52ec83",
+    url = "https://github.com/ethereum/eth2.0-spec-tests/releases/download/v1.0.0/mainnet.tar.gz",
 )

 http_archive(
@@ -264,9 +286,9 @@ buildifier_dependencies()

 git_repository(
    name = "com_google_protobuf",
-    commit = "4059c61f27eb1b06c4ee979546a238be792df0a4",
+    commit = "fde7cf7358ec7cd69e8db9be4f1fa6a5c431386a",  # v3.13.0
    remote = "https://github.com/protocolbuffers/protobuf",
-    shallow_since = "1558721209 -0700",
+    shallow_since = "1597443653 -0700",
 )

 load("@com_google_protobuf//:protobuf_deps.bzl", "protobuf_deps")
@@ -336,15 +358,26 @@ go_binary(
    urls = ["https://github.com/ferranbt/fastssz/archive/06015a5d84f9e4eefe2c21377ca678fa8f1a1b09.tar.gz"],
 )

+http_archive(
+    name = "prysm_web_ui",
+    build_file_content = """
+filegroup(
+    name = "site",
+    srcs = glob(["**/*"]),
+    visibility = ["//visibility:public"],
+)
+""",
+    sha256 = "edb80f3a695d84f6000f0e05abf7a4bbf207c03abb91219780ec97e7d6ad21c8",
+    urls = [
+        "https://github.com/prysmaticlabs/prysm-web-ui/releases/download/v1.0.0-beta.3/prysm-web-ui.tar.gz",
+    ],
+)
+
 load("//:deps.bzl", "prysm_deps")

 # gazelle:repository_macro deps.bzl%prysm_deps
 prysm_deps()

-load("@com_github_prysmaticlabs_go_ssz//:deps.bzl", "go_ssz_dependencies")
-
-go_ssz_dependencies()
-
 load("@prysm//third_party/herumi:herumi.bzl", "bls_dependencies")

 bls_dependencies()
--- a/bazel.sh
+++ b/bazel.sh
@@ -6,6 +6,6 @@

 env -i \
 PATH=/usr/bin:/bin \
- HOME=$HOME \
- GOOGLE_APPLICATION_CREDENTIALS=$GOOGLE_APPLICATION_CREDENTIALS \
+ HOME="$HOME" \
+ GOOGLE_APPLICATION_CREDENTIALS="$GOOGLE_APPLICATION_CREDENTIALS" \
 bazel "$@"
--- a/beacon-chain/BUILD.bazel
+++ b/beacon-chain/BUILD.bazel
@@ -1,153 +1,19 @@
-load("@prysm//tools/go:def.bzl", "go_library")
-load("@io_bazel_rules_go//go:def.bzl", "go_binary", "go_test")
-load("@io_bazel_rules_docker//go:image.bzl", "go_image")
-load("@io_bazel_rules_docker//container:container.bzl", "container_bundle")
-load("//tools:go_image.bzl", "go_image_alpine", "go_image_debug")
-load("@io_bazel_rules_docker//contrib:push-all.bzl", "docker_push")
+load("//tools:target_migration.bzl", "moved_targets")

-go_library(
-    name = "go_default_library",
-    srcs = [
-        "main.go",
-        "usage.go",
-    ],
-    importpath = "github.com/prysmaticlabs/prysm/beacon-chain",
-    visibility = ["//beacon-chain:__subpackages__"],
-    deps = [
-        "//beacon-chain/flags:go_default_library",
-        "//beacon-chain/node:go_default_library",
-        "//shared/cmd:go_default_library",
-        "//shared/debug:go_default_library",
-        "//shared/featureconfig:go_default_library",
-        "//shared/logutil:go_default_library",
-        "//shared/version:go_default_library",
-        "@com_github_ethereum_go_ethereum//log:go_default_library",
-        "@com_github_ipfs_go_log_v2//:go_default_library",
-        "@com_github_joonix_log//:go_default_library",
-        "@com_github_sirupsen_logrus//:go_default_library",
-        "@com_github_urfave_cli_v2//:go_default_library",
-        "@com_github_urfave_cli_v2//altsrc:go_default_library",
-        "@com_github_x_cray_logrus_prefixed_formatter//:go_default_library",
-        "@org_uber_go_automaxprocs//:go_default_library",
-    ],
-)
-
-go_image(
-    name = "image",
-    srcs = [
-        "main.go",
-        "usage.go",
-    ],
-    base = select({
-        "//tools:base_image_alpine": "//tools:alpine_cc_image",
-        "//tools:base_image_cc": "//tools:cc_image",
-        "//conditions:default": "//tools:cc_image",
-    }),
-    goarch = "amd64",
-    goos = "linux",
-    importpath = "github.com/prysmaticlabs/prysm/beacon-chain",
-    race = "off",
-    static = "off",  # Static enabled binary seems to cause issues with DNS lookup with cgo.
-    tags = ["manual"],
-    visibility = ["//visibility:private"],
-    deps = [
-        "//beacon-chain/flags:go_default_library",
-        "//beacon-chain/node:go_default_library",
-        "//shared/cmd:go_default_library",
-        "//shared/debug:go_default_library",
-        "//shared/featureconfig:go_default_library",
-        "//shared/logutil:go_default_library",
-        "//shared/version:go_default_library",
-        "@com_github_ethereum_go_ethereum//log:go_default_library",
-        "@com_github_ipfs_go_log_v2//:go_default_library",
-        "@com_github_joonix_log//:go_default_library",
-        "@com_github_sirupsen_logrus//:go_default_library",
-        "@com_github_urfave_cli_v2//:go_default_library",
-        "@com_github_urfave_cli_v2//altsrc:go_default_library",
-        "@com_github_x_cray_logrus_prefixed_formatter//:go_default_library",
-        "@org_uber_go_automaxprocs//:go_default_library",
-    ],
-)
-
-container_bundle(
-    name = "image_bundle",
-    images = {
-        "gcr.io/prysmaticlabs/prysm/beacon-chain:latest": ":image",
-        "gcr.io/prysmaticlabs/prysm/beacon-chain:{DOCKER_TAG}": ":image",
-        "index.docker.io/prysmaticlabs/prysm-beacon-chain:latest": ":image",
-        "index.docker.io/prysmaticlabs/prysm-beacon-chain:{DOCKER_TAG}": ":image",
-    },
-    tags = ["manual"],
-)
-
-go_image_debug(
-    name = "image_debug",
-    image = ":image",
-    tags = ["manual"],
-)
-
-container_bundle(
-    name = "image_bundle_debug",
-    images = {
-        "gcr.io/prysmaticlabs/prysm/beacon-chain:latest-debug": ":image_debug",
-        "gcr.io/prysmaticlabs/prysm/beacon-chain:{DOCKER_TAG}-debug": ":image_debug",
-        "index.docker.io/prysmaticlabs/prysm-beacon-chain:latest-debug": ":image_debug",
-        "index.docker.io/prysmaticlabs/prysm-beacon-chain:{DOCKER_TAG}-debug": ":image_debug",
-    },
-    tags = ["manual"],
-)
-
-go_image_alpine(
-    name = "image_alpine",
-    image = ":image",
-    tags = ["manual"],
-)
-
-container_bundle(
-    name = "image_bundle_alpine",
-    images = {
-        "gcr.io/prysmaticlabs/prysm/beacon-chain:latest-alpine": ":image_alpine",
-        "gcr.io/prysmaticlabs/prysm/beacon-chain:{DOCKER_TAG}-alpine": ":image_alpine",
-        "index.docker.io/prysmaticlabs/prysm-beacon-chain:latest-alpine": ":image_alpine",
-        "index.docker.io/prysmaticlabs/prysm-beacon-chain:{DOCKER_TAG}-alpine": ":image_alpine",
-    },
-    tags = ["manual"],
-)
-
-docker_push(
-    name = "push_images",
-    bundle = ":image_bundle",
-    tags = ["manual"],
-)
-
-docker_push(
-    name = "push_images_debug",
-    bundle = ":image_bundle_debug",
-    tags = ["manual"],
-)
-
-docker_push(
-    name = "push_images_alpine",
-    bundle = ":image_bundle_alpine",
-    tags = ["manual"],
-)
-
-go_binary(
-    name = "beacon-chain",
-    embed = [":go_default_library"],
-    visibility = [
-        "//beacon-chain:__subpackages__",
-        "//endtoend:__pkg__",
-    ],
-)
-
-go_test(
-    name = "go_default_test",
-    size = "small",
-    srcs = ["usage_test.go"],
-    embed = [":go_default_library"],
-    deps = [
-        "//shared/featureconfig:go_default_library",
-        "@com_github_urfave_cli_v2//:go_default_library",
+moved_targets(
+    [
+        ":push_images_debug",
+        ":push_images_alpine",
+        ":push_images",
+        ":image_bundle_debug",
+        ":image_debug",
+        ":image_bundle_alpine",
+        ":image_bundle",
+        ":image_with_creation_time",
+        ":image_alpine",
+        ":image",
+        ":go_default_test",
+        ":beacon-chain",
    ],
+    "//cmd/beacon-chain",
 )
--- a/beacon-chain/README.md
+++ b/beacon-chain/README.md
@@ -1,10 +1,9 @@
 # Prysmatic Labs Beacon Chain Implementation

-This is the main project folder for the beacon chain implementation of Ethereum Serenity in Golang by [Prysmatic Labs](https://prysmaticlabs.com). Before you begin, check out our [Contribution Guidelines](https://github.com/prysmaticlabs/prysm/blob/master/CONTRIBUTING.md) and join our active chat room on Discord or Gitter below:
+This is the main project folder for the beacon chain implementation of eth2 written in Go by [Prysmatic Labs](https://prysmaticlabs.com).

-[![Discord](https://user-images.githubusercontent.com/7288322/34471967-1df7808a-efbb-11e7-9088-ed0b04151291.png)](https://discord.gg/KSA7rPr)
-[![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/prysmaticlabs/prysm?badge&utm_medium=badge&utm_campaign=pr-badge)
+You can also read our main [README](https://github.com/prysmaticlabs/prysm/blob/master/README.md) and join our active chat room on Discord.

-Also, read the latest beacon chain [design spec](https://github.com/ethereum/eth2.0-specs/blob/dev/specs/phase0/beacon-chain.md), this design spec serves as a source of truth for the beacon chain implementation we follow at prysmatic labs.
-Check out the [FAQs](https://notes.ethereum.org/9MMuzWeFTTSg-3Tz_YeiBA?view). Refer this page on [why](http://email.mg2.substack.com/c/eJwlj9GOhCAMRb9G3jRQQPGBh5mM8xsbhKrsDGIAM9m_X9xN2qZtbpt7rCm4xvSjj5gLOTOmL-809CMbKXFaOKakIl4DZYr2AGyQIGjHOnWH22OiYnoIxmDijaBhhS6fcy7GvjobA9m0mSXOcnZq5GBqLkilXBZhBsus5ZK89VbKkRt-a-BZI6DzZ7iur1lQ953KJ9bemnxgahuQU9XJu6pFPdu8meT8vragzEjpMCwMGLlgLo6h5z1JumQTu4IJd4v15xqMf_8ZLP_Y1bSLdbnrD-LL71i2Kj7DLxaWWF4)
-we are combining sharding and casper together.
+[![Discord](https://user-images.githubusercontent.com/7288322/34471967-1df7808a-efbb-11e7-9088-ed0b04151291.png)](https://discord.gg/CTYGPUJ)
+
+Also, read the official beacon chain [specification](https://github.com/ethereum/eth2.0-specs/blob/master/specs/phase0/beacon-chain.md), this design spec serves as a source of truth for the beacon chain implementation we follow at Prysmatic Labs.
--- a/beacon-chain/archiver/BUILD.bazel
+++ b/beacon-chain/archiver/BUILD.bazel
@@ -1,46 +0,0 @@
-load("@prysm//tools/go:def.bzl", "go_library")
-load("@io_bazel_rules_go//go:def.bzl", "go_test")
-
-go_library(
-    name = "go_default_library",
-    srcs = ["service.go"],
-    importpath = "github.com/prysmaticlabs/prysm/beacon-chain/archiver",
-    visibility = ["//beacon-chain:__subpackages__"],
-    deps = [
-        "//beacon-chain/blockchain:go_default_library",
-        "//beacon-chain/core/feed:go_default_library",
-        "//beacon-chain/core/feed/state:go_default_library",
-        "//beacon-chain/core/helpers:go_default_library",
-        "//beacon-chain/core/validators:go_default_library",
-        "//beacon-chain/db:go_default_library",
-        "//beacon-chain/state:go_default_library",
-        "//proto/beacon/p2p/v1:go_default_library",
-        "//shared/params:go_default_library",
-        "@com_github_pkg_errors//:go_default_library",
-        "@com_github_prysmaticlabs_ethereumapis//eth/v1alpha1:go_default_library",
-        "@com_github_sirupsen_logrus//:go_default_library",
-    ],
-)
-
-go_test(
-    name = "go_default_test",
-    srcs = ["service_test.go"],
-    embed = [":go_default_library"],
-    deps = [
-        "//beacon-chain/blockchain/testing:go_default_library",
-        "//beacon-chain/core/epoch/precompute:go_default_library",
-        "//beacon-chain/core/feed:go_default_library",
-        "//beacon-chain/core/feed/state:go_default_library",
-        "//beacon-chain/core/helpers:go_default_library",
-        "//beacon-chain/db:go_default_library",
-        "//beacon-chain/db/testing:go_default_library",
-        "//beacon-chain/state:go_default_library",
-        "//proto/beacon/p2p/v1:go_default_library",
-        "//shared/params:go_default_library",
-        "//shared/testutil:go_default_library",
-        "@com_github_gogo_protobuf//proto:go_default_library",
-        "@com_github_prysmaticlabs_ethereumapis//eth/v1alpha1:go_default_library",
-        "@com_github_sirupsen_logrus//:go_default_library",
-        "@com_github_sirupsen_logrus//hooks/test:go_default_library",
-    ],
-)
--- a/beacon-chain/archiver/service.go
+++ b/beacon-chain/archiver/service.go
@@ -1,200 +0,0 @@
-package archiver
-
-import (
-	"context"
-	"fmt"
-
-	"github.com/pkg/errors"
-	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
-	"github.com/prysmaticlabs/prysm/beacon-chain/blockchain"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/feed"
-	statefeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/state"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/validators"
-	"github.com/prysmaticlabs/prysm/beacon-chain/db"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
-	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
-	"github.com/prysmaticlabs/prysm/shared/params"
-	"github.com/sirupsen/logrus"
-)
-
-var log = logrus.WithField("prefix", "archiver")
-
-// Service defining archiver functionality for persisting checkpointed
-// beacon chain information to a database backend for historical purposes.
-type Service struct {
-	ctx                  context.Context
-	cancel               context.CancelFunc
-	beaconDB             db.NoHeadAccessDatabase
-	headFetcher          blockchain.HeadFetcher
-	participationFetcher blockchain.ParticipationFetcher
-	stateNotifier        statefeed.Notifier
-	lastArchivedEpoch    uint64
-}
-
-// Config options for the archiver service.
-type Config struct {
-	BeaconDB             db.NoHeadAccessDatabase
-	HeadFetcher          blockchain.HeadFetcher
-	ParticipationFetcher blockchain.ParticipationFetcher
-	StateNotifier        statefeed.Notifier
-}
-
-// NewArchiverService initializes the service from configuration options.
-func NewArchiverService(ctx context.Context, cfg *Config) *Service {
-	ctx, cancel := context.WithCancel(ctx)
-	return &Service{
-		ctx:                  ctx,
-		cancel:               cancel,
-		beaconDB:             cfg.BeaconDB,
-		headFetcher:          cfg.HeadFetcher,
-		participationFetcher: cfg.ParticipationFetcher,
-		stateNotifier:        cfg.StateNotifier,
-	}
-}
-
-// Start the archiver service event loop.
-func (s *Service) Start() {
-	go s.run(s.ctx)
-}
-
-// Stop the archiver service event loop.
-func (s *Service) Stop() error {
-	defer s.cancel()
-	return nil
-}
-
-// Status reports the healthy status of the archiver. Returning nil means service
-// is correctly running without error.
-func (s *Service) Status() error {
-	return nil
-}
-
-// We archive committee information pertaining to the head state's epoch.
-func (s *Service) archiveCommitteeInfo(ctx context.Context, headState *state.BeaconState, epoch uint64) error {
-	proposerSeed, err := helpers.Seed(headState, epoch, params.BeaconConfig().DomainBeaconProposer)
-	if err != nil {
-		return errors.Wrap(err, "could not generate seed")
-	}
-	attesterSeed, err := helpers.Seed(headState, epoch, params.BeaconConfig().DomainBeaconAttester)
-	if err != nil {
-		return errors.Wrap(err, "could not generate seed")
-	}
-
-	info := &pb.ArchivedCommitteeInfo{
-		ProposerSeed: proposerSeed[:],
-		AttesterSeed: attesterSeed[:],
-	}
-	if err := s.beaconDB.SaveArchivedCommitteeInfo(ctx, epoch, info); err != nil {
-		return errors.Wrap(err, "could not archive committee info")
-	}
-	return nil
-}
-
-// We archive active validator set changes that happened during the previous epoch.
-func (s *Service) archiveActiveSetChanges(ctx context.Context, headState *state.BeaconState, epoch uint64) error {
-	prevEpoch := epoch - 1
-	vals := headState.Validators()
-	activations := validators.ActivatedValidatorIndices(prevEpoch, vals)
-	slashings := validators.SlashedValidatorIndices(prevEpoch, vals)
-	activeValidatorCount, err := helpers.ActiveValidatorCount(headState, prevEpoch)
-	if err != nil {
-		return errors.Wrap(err, "could not get active validator count")
-	}
-	exited, err := validators.ExitedValidatorIndices(prevEpoch, vals, activeValidatorCount)
-	if err != nil {
-		return errors.Wrap(err, "could not determine exited validator indices")
-	}
-	activeSetChanges := &pb.ArchivedActiveSetChanges{
-		Activated: activations,
-		Exited:    exited,
-		Slashed:   slashings,
-	}
-	if err := s.beaconDB.SaveArchivedActiveValidatorChanges(ctx, prevEpoch, activeSetChanges); err != nil {
-		return errors.Wrap(err, "could not archive active validator set changes")
-	}
-	return nil
-}
-
-// We compute participation metrics by first retrieving the head state and
-// matching validator attestations during the epoch.
-func (s *Service) archiveParticipation(ctx context.Context, epoch uint64) error {
-	pBal := s.participationFetcher.Participation(epoch)
-	participation := &ethpb.ValidatorParticipation{}
-	if pBal != nil {
-		participation = &ethpb.ValidatorParticipation{
-			EligibleEther:           pBal.ActivePrevEpoch,
-			VotedEther:              pBal.PrevEpochTargetAttested,
-			GlobalParticipationRate: float32(pBal.PrevEpochTargetAttested) / float32(pBal.ActivePrevEpoch),
-		}
-	}
-	return s.beaconDB.SaveArchivedValidatorParticipation(ctx, epoch, participation)
-}
-
-// We archive validator balances and active indices.
-func (s *Service) archiveBalances(ctx context.Context, balances []uint64, epoch uint64) error {
-	if err := s.beaconDB.SaveArchivedBalances(ctx, epoch, balances); err != nil {
-		return errors.Wrap(err, "could not archive balances")
-	}
-	return nil
-}
-
-func (s *Service) run(ctx context.Context) {
-	stateChannel := make(chan *feed.Event, 1)
-	stateSub := s.stateNotifier.StateFeed().Subscribe(stateChannel)
-	defer stateSub.Unsubscribe()
-	for {
-		select {
-		case event := <-stateChannel:
-			if event.Type == statefeed.BlockProcessed {
-				data, ok := event.Data.(*statefeed.BlockProcessedData)
-				if !ok {
-					log.Error("Event feed data is not type *statefeed.BlockProcessedData")
-					continue
-				}
-				log.WithField("headRoot", fmt.Sprintf("%#x", data.BlockRoot)).Debug("Received block processed event")
-				headState, err := s.headFetcher.HeadState(ctx)
-				if err != nil {
-					log.WithError(err).Error("Head state is not available")
-					continue
-				}
-				slot := headState.Slot()
-				currentEpoch := helpers.SlotToEpoch(slot)
-				if !helpers.IsEpochEnd(slot) && currentEpoch <= s.lastArchivedEpoch {
-					continue
-				}
-				epochToArchive := currentEpoch
-				if !helpers.IsEpochEnd(slot) {
-					epochToArchive--
-				}
-				if err := s.archiveCommitteeInfo(ctx, headState, epochToArchive); err != nil {
-					log.WithError(err).Error("Could not archive committee info")
-					continue
-				}
-				if err := s.archiveActiveSetChanges(ctx, headState, epochToArchive); err != nil {
-					log.WithError(err).Error("Could not archive active validator set changes")
-					continue
-				}
-				if err := s.archiveParticipation(ctx, epochToArchive); err != nil {
-					log.WithError(err).Error("Could not archive validator participation")
-					continue
-				}
-				if err := s.archiveBalances(ctx, headState.Balances(), epochToArchive); err != nil {
-					log.WithError(err).Error("Could not archive validator balances and active indices")
-					continue
-				}
-				log.WithField(
-					"epoch",
-					epochToArchive,
-				).Debug("Successfully archived beacon chain data during epoch")
-				s.lastArchivedEpoch = epochToArchive
-			}
-		case <-s.ctx.Done():
-			log.Debug("Context closed, exiting goroutine")
-			return
-		case err := <-stateSub.Err():
-			log.WithError(err).Error("Subscription to state feed notifier failed")
-			return
-		}
-	}
-}
--- a/beacon-chain/archiver/service_test.go
+++ b/beacon-chain/archiver/service_test.go
@@ -1,474 +0,0 @@
-package archiver
-
-import (
-	"context"
-	"fmt"
-	"io/ioutil"
-	"reflect"
-	"testing"
-
-	"github.com/gogo/protobuf/proto"
-	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
-	mock "github.com/prysmaticlabs/prysm/beacon-chain/blockchain/testing"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/epoch/precompute"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/feed"
-	statefeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/state"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	"github.com/prysmaticlabs/prysm/beacon-chain/db"
-	dbutil "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
-	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
-	"github.com/prysmaticlabs/prysm/shared/params"
-	"github.com/prysmaticlabs/prysm/shared/testutil"
-	"github.com/sirupsen/logrus"
-	logTest "github.com/sirupsen/logrus/hooks/test"
-)
-
-func init() {
-	logrus.SetLevel(logrus.DebugLevel)
-	logrus.SetOutput(ioutil.Discard)
-}
-
-func TestArchiverService_ReceivesBlockProcessedEvent(t *testing.T) {
-	hook := logTest.NewGlobal()
-	svc, _ := setupService(t)
-	st := testutil.NewBeaconState()
-	if err := st.SetSlot(1); err != nil {
-		t.Fatal(err)
-	}
-	svc.headFetcher = &mock.ChainService{
-		State: st,
-	}
-
-	event := &feed.Event{
-		Type: statefeed.BlockProcessed,
-		Data: &statefeed.BlockProcessedData{
-			BlockRoot: [32]byte{1, 2, 3},
-			Verified:  true,
-		},
-	}
-	triggerStateEvent(t, svc, event)
-	testutil.AssertLogsContain(t, hook, fmt.Sprintf("%#x", event.Data.(*statefeed.BlockProcessedData).BlockRoot))
-	testutil.AssertLogsContain(t, hook, "Received block processed event")
-}
-
-func TestArchiverService_OnlyArchiveAtEpochEnd(t *testing.T) {
-	hook := logTest.NewGlobal()
-	svc, _ := setupService(t)
-	// The head state is NOT an epoch end.
-	st := testutil.NewBeaconState()
-	if err := st.SetSlot(params.BeaconConfig().SlotsPerEpoch - 2); err != nil {
-		t.Fatal(err)
-	}
-	svc.headFetcher = &mock.ChainService{
-		State: st,
-	}
-	event := &feed.Event{
-		Type: statefeed.BlockProcessed,
-		Data: &statefeed.BlockProcessedData{
-			BlockRoot: [32]byte{1, 2, 3},
-			Verified:  true,
-		},
-	}
-	triggerStateEvent(t, svc, event)
-
-	// The context should have been canceled.
-	if svc.ctx.Err() != context.Canceled {
-		t.Error("context was not canceled")
-	}
-	testutil.AssertLogsContain(t, hook, "Received block processed event")
-	// The service should ONLY log any archival logs if we receive a
-	// head slot that is an epoch end.
-	testutil.AssertLogsDoNotContain(t, hook, "Successfully archived")
-}
-
-func TestArchiverService_ArchivesEvenThroughSkipSlot(t *testing.T) {
-	hook := logTest.NewGlobal()
-	svc, _ := setupService(t)
-	validatorCount := uint64(100)
-	headState, err := setupState(validatorCount)
-	if err != nil {
-		t.Fatal(err)
-	}
-	event := &feed.Event{
-		Type: statefeed.BlockProcessed,
-		Data: &statefeed.BlockProcessedData{
-			BlockRoot: [32]byte{1, 2, 3},
-			Verified:  true,
-		},
-	}
-
-	exitRoutine := make(chan bool)
-	go func() {
-		svc.run(svc.ctx)
-		<-exitRoutine
-	}()
-
-	// Send out an event every slot, skipping the end slot of the epoch.
-	for i := uint64(0); i < params.BeaconConfig().SlotsPerEpoch+1; i++ {
-		if err := headState.SetSlot(i); err != nil {
-			t.Fatal(err)
-		}
-		svc.headFetcher = &mock.ChainService{
-			State: headState,
-		}
-		if helpers.IsEpochEnd(i) {
-			continue
-		}
-		// Send in a loop to ensure it is delivered (busy wait for the service to subscribe to the state feed).
-		for sent := 0; sent == 0; {
-			sent = svc.stateNotifier.StateFeed().Send(event)
-		}
-	}
-	if err := svc.Stop(); err != nil {
-		t.Fatal(err)
-	}
-	exitRoutine <- true
-
-	// The context should have been canceled.
-	if svc.ctx.Err() != context.Canceled {
-		t.Error("context was not canceled")
-	}
-
-	testutil.AssertLogsContain(t, hook, "Received block processed event")
-	// Even though there was a skip slot, we should still be able to archive
-	// upon the next block event afterwards.
-	testutil.AssertLogsContain(t, hook, "Successfully archived")
-}
-
-func TestArchiverService_ComputesAndSavesParticipation(t *testing.T) {
-	hook := logTest.NewGlobal()
-	validatorCount := uint64(100)
-	headState, err := setupState(validatorCount)
-	if err != nil {
-		t.Fatal(err)
-	}
-	svc, _ := setupService(t)
-	svc.headFetcher = &mock.ChainService{
-		State: headState,
-	}
-	event := &feed.Event{
-		Type: statefeed.BlockProcessed,
-		Data: &statefeed.BlockProcessedData{
-			BlockRoot: [32]byte{1, 2, 3},
-			Verified:  true,
-		},
-	}
-	triggerStateEvent(t, svc, event)
-
-	attestedBalance := uint64(1)
-
-	currentEpoch := helpers.CurrentEpoch(headState)
-	wanted := &ethpb.ValidatorParticipation{
-		VotedEther:              attestedBalance,
-		EligibleEther:           validatorCount * params.BeaconConfig().MaxEffectiveBalance,
-		GlobalParticipationRate: float32(attestedBalance) / float32(validatorCount*params.BeaconConfig().MaxEffectiveBalance),
-	}
-
-	retrieved, err := svc.beaconDB.ArchivedValidatorParticipation(svc.ctx, currentEpoch)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	if !proto.Equal(wanted, retrieved) {
-		t.Errorf("Wanted participation for epoch %d %v, retrieved %v", currentEpoch-1, wanted, retrieved)
-	}
-	testutil.AssertLogsContain(t, hook, "Successfully archived")
-}
-
-func TestArchiverService_SavesIndicesAndBalances(t *testing.T) {
-	hook := logTest.NewGlobal()
-	validatorCount := uint64(100)
-	headState, err := setupState(validatorCount)
-	if err != nil {
-		t.Fatal(err)
-	}
-	svc, _ := setupService(t)
-	svc.headFetcher = &mock.ChainService{
-		State: headState,
-	}
-	event := &feed.Event{
-		Type: statefeed.BlockProcessed,
-		Data: &statefeed.BlockProcessedData{
-			BlockRoot: [32]byte{1, 2, 3},
-			Verified:  true,
-		},
-	}
-	triggerStateEvent(t, svc, event)
-
-	retrieved, err := svc.beaconDB.ArchivedBalances(svc.ctx, helpers.CurrentEpoch(headState))
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !reflect.DeepEqual(headState.Balances(), retrieved) {
-		t.Errorf(
-			"Wanted balances for epoch %d %v, retrieved %v",
-			helpers.CurrentEpoch(headState),
-			headState.Balances(),
-			retrieved,
-		)
-	}
-	testutil.AssertLogsContain(t, hook, "Successfully archived")
-}
-
-func TestArchiverService_SavesCommitteeInfo(t *testing.T) {
-	hook := logTest.NewGlobal()
-	validatorCount := uint64(100)
-	headState, err := setupState(validatorCount)
-	if err != nil {
-		t.Fatal(err)
-	}
-	svc, _ := setupService(t)
-	svc.headFetcher = &mock.ChainService{
-		State: headState,
-	}
-	event := &feed.Event{
-		Type: statefeed.BlockProcessed,
-		Data: &statefeed.BlockProcessedData{
-			BlockRoot: [32]byte{1, 2, 3},
-			Verified:  true,
-		},
-	}
-	triggerStateEvent(t, svc, event)
-
-	currentEpoch := helpers.CurrentEpoch(headState)
-	proposerSeed, err := helpers.Seed(headState, currentEpoch, params.BeaconConfig().DomainBeaconProposer)
-	if err != nil {
-		t.Fatal(err)
-	}
-	attesterSeed, err := helpers.Seed(headState, currentEpoch, params.BeaconConfig().DomainBeaconAttester)
-	if err != nil {
-		t.Fatal(err)
-	}
-	wanted := &pb.ArchivedCommitteeInfo{
-		ProposerSeed: proposerSeed[:],
-		AttesterSeed: attesterSeed[:],
-	}
-
-	retrieved, err := svc.beaconDB.ArchivedCommitteeInfo(svc.ctx, helpers.CurrentEpoch(headState))
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !proto.Equal(wanted, retrieved) {
-		t.Errorf(
-			"Wanted committee info for epoch %d %v, retrieved %v",
-			helpers.CurrentEpoch(headState),
-			wanted,
-			retrieved,
-		)
-	}
-	testutil.AssertLogsContain(t, hook, "Successfully archived")
-}
-
-func TestArchiverService_SavesActivatedValidatorChanges(t *testing.T) {
-	hook := logTest.NewGlobal()
-	validatorCount := uint64(100)
-	headState, err := setupState(validatorCount)
-	if err != nil {
-		t.Fatal(err)
-	}
-	svc, beaconDB := setupService(t)
-	svc.headFetcher = &mock.ChainService{
-		State: headState,
-	}
-	prevEpoch := helpers.PrevEpoch(headState)
-	delayedActEpoch := helpers.ActivationExitEpoch(prevEpoch)
-	val1, err := headState.ValidatorAtIndex(4)
-	if err != nil {
-		t.Fatal(err)
-	}
-	val1.ActivationEpoch = delayedActEpoch
-	val2, err := headState.ValidatorAtIndex(5)
-	if err != nil {
-		t.Fatal(err)
-	}
-	val2.ActivationEpoch = delayedActEpoch
-	if err := headState.UpdateValidatorAtIndex(4, val1); err != nil {
-		t.Fatal(err)
-	}
-	if err := headState.UpdateValidatorAtIndex(5, val1); err != nil {
-		t.Fatal(err)
-	}
-	event := &feed.Event{
-		Type: statefeed.BlockProcessed,
-		Data: &statefeed.BlockProcessedData{
-			BlockRoot: [32]byte{1, 2, 3},
-			Verified:  true,
-		},
-	}
-	triggerStateEvent(t, svc, event)
-
-	retrieved, err := beaconDB.ArchivedActiveValidatorChanges(svc.ctx, prevEpoch)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if retrieved == nil {
-		t.Fatal("Retrieved indices are nil")
-	}
-	if len(retrieved.Activated) != 98 {
-		t.Error("Did not get wanted active length")
-	}
-	testutil.AssertLogsContain(t, hook, "Successfully archived")
-}
-
-func TestArchiverService_SavesSlashedValidatorChanges(t *testing.T) {
-	hook := logTest.NewGlobal()
-	validatorCount := uint64(100)
-	headState, err := setupState(validatorCount)
-	if err != nil {
-		t.Fatal(err)
-	}
-	svc, beaconDB := setupService(t)
-	svc.headFetcher = &mock.ChainService{
-		State: headState,
-	}
-	prevEpoch := helpers.PrevEpoch(headState)
-	val1, err := headState.ValidatorAtIndex(95)
-	if err != nil {
-		t.Fatal(err)
-	}
-	val1.Slashed = true
-	val2, err := headState.ValidatorAtIndex(96)
-	if err != nil {
-		t.Fatal(err)
-	}
-	val2.Slashed = true
-	if err := headState.UpdateValidatorAtIndex(95, val1); err != nil {
-		t.Fatal(err)
-	}
-	if err := headState.UpdateValidatorAtIndex(96, val1); err != nil {
-		t.Fatal(err)
-	}
-	event := &feed.Event{
-		Type: statefeed.BlockProcessed,
-		Data: &statefeed.BlockProcessedData{
-			BlockRoot: [32]byte{1, 2, 3},
-			Verified:  true,
-		},
-	}
-	triggerStateEvent(t, svc, event)
-
-	retrieved, err := beaconDB.ArchivedActiveValidatorChanges(svc.ctx, prevEpoch)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if retrieved == nil {
-		t.Fatal("Retrieved indices are nil")
-	}
-	if !reflect.DeepEqual(retrieved.Slashed, []uint64{95, 96}) {
-		t.Errorf("Wanted indices 95, 96 slashed, received %v", retrieved.Slashed)
-	}
-	testutil.AssertLogsContain(t, hook, "Successfully archived")
-}
-
-func TestArchiverService_SavesExitedValidatorChanges(t *testing.T) {
-	hook := logTest.NewGlobal()
-	validatorCount := uint64(100)
-	headState, err := setupState(validatorCount)
-	if err != nil {
-		t.Fatal(err)
-	}
-	svc, beaconDB := setupService(t)
-	svc.headFetcher = &mock.ChainService{
-		State: headState,
-	}
-	prevEpoch := helpers.PrevEpoch(headState)
-	val, err := headState.ValidatorAtIndex(95)
-	if err != nil {
-		t.Fatal(err)
-	}
-	val.ExitEpoch = prevEpoch
-	val.WithdrawableEpoch = prevEpoch + params.BeaconConfig().MinValidatorWithdrawabilityDelay
-	if err := headState.UpdateValidatorAtIndex(95, val); err != nil {
-		t.Fatal(err)
-	}
-	event := &feed.Event{
-		Type: statefeed.BlockProcessed,
-		Data: &statefeed.BlockProcessedData{
-			BlockRoot: [32]byte{1, 2, 3},
-			Verified:  true,
-		},
-	}
-	triggerStateEvent(t, svc, event)
-	testutil.AssertLogsContain(t, hook, "Successfully archived")
-	retrieved, err := beaconDB.ArchivedActiveValidatorChanges(svc.ctx, prevEpoch)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if retrieved == nil {
-		t.Fatal("Retrieved indices are nil")
-	}
-	if !reflect.DeepEqual(retrieved.Exited, []uint64{95}) {
-		t.Errorf("Wanted indices 95 exited, received %v", retrieved.Exited)
-	}
-}
-
-func setupState(validatorCount uint64) (*stateTrie.BeaconState, error) {
-	validators := make([]*ethpb.Validator, validatorCount)
-	balances := make([]uint64, validatorCount)
-	for i := 0; i < len(validators); i++ {
-		validators[i] = &ethpb.Validator{
-			ExitEpoch:         params.BeaconConfig().FarFutureEpoch,
-			WithdrawableEpoch: params.BeaconConfig().FarFutureEpoch,
-			EffectiveBalance:  params.BeaconConfig().MaxEffectiveBalance,
-		}
-		balances[i] = params.BeaconConfig().MaxEffectiveBalance
-	}
-
-	atts := []*pb.PendingAttestation{{Data: &ethpb.AttestationData{Target: &ethpb.Checkpoint{}}}}
-
-	// We initialize a head state that has attestations from participated
-	// validators in a simulated fashion.
-	st := testutil.NewBeaconState()
-	if err := st.SetSlot((2 * params.BeaconConfig().SlotsPerEpoch) - 1); err != nil {
-		return nil, err
-	}
-	if err := st.SetValidators(validators); err != nil {
-		return nil, err
-	}
-	if err := st.SetBalances(balances); err != nil {
-		return nil, err
-	}
-	if err := st.SetCurrentEpochAttestations(atts); err != nil {
-		return nil, err
-	}
-	return st, nil
-}
-
-func setupService(t *testing.T) (*Service, db.Database) {
-	beaconDB, _ := dbutil.SetupDB(t)
-	ctx, cancel := context.WithCancel(context.Background())
-	validatorCount := uint64(100)
-	totalBalance := validatorCount * params.BeaconConfig().MaxEffectiveBalance
-	mockChainService := &mock.ChainService{}
-	return &Service{
-		beaconDB:      beaconDB,
-		ctx:           ctx,
-		cancel:        cancel,
-		stateNotifier: mockChainService.StateNotifier(),
-		participationFetcher: &mock.ChainService{
-			Balance: &precompute.Balance{ActivePrevEpoch: totalBalance, PrevEpochTargetAttested: 1}},
-	}, beaconDB
-}
-
-func triggerStateEvent(t *testing.T, svc *Service, event *feed.Event) {
-	exitRoutine := make(chan bool)
-	go func() {
-		svc.run(svc.ctx)
-		<-exitRoutine
-	}()
-
-	// Send in a loop to ensure it is delivered (busy wait for the service to subscribe to the state feed).
-	for sent := 0; sent == 0; {
-		sent = svc.stateNotifier.StateFeed().Send(event)
-	}
-	if err := svc.Stop(); err != nil {
-		t.Fatal(err)
-	}
-	exitRoutine <- true
-
-	// The context should have been canceled.
-	if svc.ctx.Err() != context.Canceled {
-		t.Error("context was not canceled")
-	}
-}
--- a/beacon-chain/blockchain/BUILD.bazel
+++ b/beacon-chain/blockchain/BUILD.bazel
@@ -17,13 +17,16 @@ go_library(
        "receive_attestation.go",
        "receive_block.go",
        "service.go",
+        "weak_subjectivity_checks.go",
    ],
    importpath = "github.com/prysmaticlabs/prysm/beacon-chain/blockchain",
-    visibility = ["//beacon-chain:__subpackages__"],
+    visibility = [
+        "//beacon-chain:__subpackages__",
+        "//fuzz:__pkg__",
+    ],
    deps = [
        "//beacon-chain/cache:go_default_library",
        "//beacon-chain/cache/depositcache:go_default_library",
-        "//beacon-chain/core/blocks:go_default_library",
        "//beacon-chain/core/epoch/precompute:go_default_library",
        "//beacon-chain/core/feed:go_default_library",
        "//beacon-chain/core/feed/state:go_default_library",
@@ -31,7 +34,6 @@ go_library(
        "//beacon-chain/core/state:go_default_library",
        "//beacon-chain/db:go_default_library",
        "//beacon-chain/db/filters:go_default_library",
-        "//beacon-chain/flags:go_default_library",
        "//beacon-chain/forkchoice:go_default_library",
        "//beacon-chain/forkchoice/protoarray:go_default_library",
        "//beacon-chain/operations/attestations:go_default_library",
@@ -39,21 +41,25 @@ go_library(
        "//beacon-chain/operations/voluntaryexits:go_default_library",
        "//beacon-chain/p2p:go_default_library",
        "//beacon-chain/powchain:go_default_library",
-        "//beacon-chain/state:go_default_library",
+        "//beacon-chain/state/interface:go_default_library",
+        "//beacon-chain/state/stateV0:go_default_library",
        "//beacon-chain/state/stategen:go_default_library",
-        "//beacon-chain/state/stateutil:go_default_library",
+        "//cmd/beacon-chain/flags:go_default_library",
        "//proto/beacon/p2p/v1:go_default_library",
        "//shared/attestationutil:go_default_library",
+        "//shared/bls:go_default_library",
        "//shared/bytesutil:go_default_library",
        "//shared/featureconfig:go_default_library",
+        "//shared/mputil:go_default_library",
        "//shared/params:go_default_library",
-        "//shared/roughtime:go_default_library",
        "//shared/slotutil:go_default_library",
+        "//shared/timeutils:go_default_library",
        "//shared/traceutil:go_default_library",
        "@com_github_emicklei_dot//:go_default_library",
        "@com_github_pkg_errors//:go_default_library",
        "@com_github_prometheus_client_golang//prometheus:go_default_library",
        "@com_github_prometheus_client_golang//prometheus/promauto:go_default_library",
+        "@com_github_prysmaticlabs_eth2_types//:go_default_library",
        "@com_github_prysmaticlabs_ethereumapis//eth/v1alpha1:go_default_library",
        "@com_github_sirupsen_logrus//:go_default_library",
        "@io_opencensus_go//trace:go_default_library",
@@ -72,16 +78,24 @@ go_test(
    name = "go_raceoff_test",
    size = "medium",
    srcs = [
+        "blockchain_test.go",
        "chain_info_test.go",
+        "checktags_test.go",
        "head_test.go",
-        "init_sync_process_block_test.go",
+        "info_test.go",
+        "init_test.go",
+        "metrics_test.go",
        "process_attestation_test.go",
        "process_block_test.go",
        "receive_attestation_test.go",
+        "receive_block_test.go",
        "service_test.go",
+        "weak_subjectivity_checks_test.go",
    ],
    embed = [":go_default_library"],
+    gotags = ["develop"],
    deps = [
+        "//beacon-chain/blockchain/testing:go_default_library",
        "//beacon-chain/cache/depositcache:go_default_library",
        "//beacon-chain/core/blocks:go_default_library",
        "//beacon-chain/core/helpers:go_default_library",
@@ -97,12 +111,13 @@ go_test(
        "//shared/event:go_default_library",
        "//shared/params:go_default_library",
        "//shared/testutil:go_default_library",
+        "//shared/testutil/assert:go_default_library",
+        "//shared/testutil/require:go_default_library",
        "@com_github_ethereum_go_ethereum//:go_default_library",
        "@com_github_ethereum_go_ethereum//common:go_default_library",
        "@com_github_ethereum_go_ethereum//core/types:go_default_library",
        "@com_github_gogo_protobuf//proto:go_default_library",
        "@com_github_prysmaticlabs_ethereumapis//eth/v1alpha1:go_default_library",
-        "@com_github_prysmaticlabs_go_ssz//:go_default_library",
        "@com_github_sirupsen_logrus//:go_default_library",
        "@com_github_sirupsen_logrus//hooks/test:go_default_library",
        "@in_gopkg_d4l3k_messagediff_v1//:go_default_library",
@@ -114,6 +129,9 @@ go_test(
    name = "go_raceon_test",
    srcs = [
        "chain_info_norace_test.go",
+        "checktags_test.go",
+        "init_test.go",
+        "receive_block_test.go",
        "service_norace_test.go",
    ],
    embed = [":go_default_library"],
@@ -124,9 +142,11 @@ go_test(
        # See: https://github.com/etcd-io/bbolt/issues/187.
        "-d=checkptr=0",
    ],
+    gotags = ["develop"],
    race = "on",
    tags = ["race_on"],
    deps = [
+        "//beacon-chain/blockchain/testing:go_default_library",
        "//beacon-chain/cache/depositcache:go_default_library",
        "//beacon-chain/core/blocks:go_default_library",
        "//beacon-chain/core/helpers:go_default_library",
@@ -140,12 +160,13 @@ go_test(
        "//shared/event:go_default_library",
        "//shared/params:go_default_library",
        "//shared/testutil:go_default_library",
+        "//shared/testutil/assert:go_default_library",
+        "//shared/testutil/require:go_default_library",
        "@com_github_ethereum_go_ethereum//:go_default_library",
        "@com_github_ethereum_go_ethereum//common:go_default_library",
        "@com_github_ethereum_go_ethereum//core/types:go_default_library",
        "@com_github_gogo_protobuf//proto:go_default_library",
        "@com_github_prysmaticlabs_ethereumapis//eth/v1alpha1:go_default_library",
-        "@com_github_prysmaticlabs_go_ssz//:go_default_library",
        "@com_github_sirupsen_logrus//:go_default_library",
        "@com_github_sirupsen_logrus//hooks/test:go_default_library",
        "@org_golang_x_net//context:go_default_library",
--- a/beacon-chain/blockchain/blockchain_test.go
+++ b/beacon-chain/blockchain/blockchain_test.go
@@ -0,0 +1,15 @@
+package blockchain
+
+import (
+	"io/ioutil"
+	"testing"
+
+	"github.com/sirupsen/logrus"
+)
+
+func TestMain(m *testing.M) {
+	logrus.SetLevel(logrus.DebugLevel)
+	logrus.SetOutput(ioutil.Discard)
+
+	m.Run()
+}
--- a/beacon-chain/blockchain/chain_info.go
+++ b/beacon-chain/blockchain/chain_info.go
@@ -4,12 +4,12 @@ import (
 	"context"
 	"time"

+	types "github.com/prysmaticlabs/eth2-types"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/epoch/precompute"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateutil"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateV0"
 	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
@@ -28,7 +28,7 @@ type ChainInfoFetcher interface {
 // TimeFetcher retrieves the Eth2 data that's related to time.
 type TimeFetcher interface {
 	GenesisTime() time.Time
-	CurrentSlot() uint64
+	CurrentSlot() types.Slot
 }

 // GenesisFetcher retrieves the eth2 data related to its genesis.
@@ -39,15 +39,16 @@ type GenesisFetcher interface {
 // HeadFetcher defines a common interface for methods in blockchain service which
 // directly retrieves head related data.
 type HeadFetcher interface {
-	HeadSlot() uint64
+	HeadSlot() types.Slot
 	HeadRoot(ctx context.Context) ([]byte, error)
 	HeadBlock(ctx context.Context) (*ethpb.SignedBeaconBlock, error)
-	HeadState(ctx context.Context) (*state.BeaconState, error)
-	HeadValidatorsIndices(ctx context.Context, epoch uint64) ([]uint64, error)
-	HeadSeed(ctx context.Context, epoch uint64) ([32]byte, error)
+	HeadState(ctx context.Context) (iface.BeaconState, error)
+	HeadValidatorsIndices(ctx context.Context, epoch types.Epoch) ([]types.ValidatorIndex, error)
+	HeadSeed(ctx context.Context, epoch types.Epoch) ([32]byte, error)
 	HeadGenesisValidatorRoot() [32]byte
 	HeadETH1Data() *ethpb.Eth1Data
 	ProtoArrayStore() *protoarray.Store
+	ChainHeads() ([][32]byte, []types.Slot)
 }

 // ForkFetcher retrieves the current fork information of the Ethereum beacon chain.
@@ -58,6 +59,7 @@ type ForkFetcher interface {
 // CanonicalFetcher retrieves the current chain's canonical information.
 type CanonicalFetcher interface {
 	IsCanonical(ctx context.Context, blockRoot [32]byte) (bool, error)
+	VerifyBlkDescendant(ctx context.Context, blockRoot [32]byte) error
 }

 // FinalizationFetcher defines a common interface for methods in blockchain service which
@@ -68,19 +70,13 @@ type FinalizationFetcher interface {
 	PreviousJustifiedCheckpt() *ethpb.Checkpoint
 }

-// ParticipationFetcher defines a common interface for methods in blockchain service which
-// directly retrieves validator participation related data.
-type ParticipationFetcher interface {
-	Participation(epoch uint64) *precompute.Balance
-}
-
 // FinalizedCheckpt returns the latest finalized checkpoint from head state.
 func (s *Service) FinalizedCheckpt() *ethpb.Checkpoint {
 	if s.finalizedCheckpt == nil {
 		return &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
 	}

-	return state.CopyCheckpoint(s.finalizedCheckpt)
+	return stateV0.CopyCheckpoint(s.finalizedCheckpt)
 }

 // CurrentJustifiedCheckpt returns the current justified checkpoint from head state.
@@ -89,7 +85,7 @@ func (s *Service) CurrentJustifiedCheckpt() *ethpb.Checkpoint {
 		return &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
 	}

-	return state.CopyCheckpoint(s.justifiedCheckpt)
+	return stateV0.CopyCheckpoint(s.justifiedCheckpt)
 }

 // PreviousJustifiedCheckpt returns the previous justified checkpoint from head state.
@@ -98,11 +94,14 @@ func (s *Service) PreviousJustifiedCheckpt() *ethpb.Checkpoint {
 		return &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}
 	}

-	return state.CopyCheckpoint(s.prevJustifiedCheckpt)
+	return stateV0.CopyCheckpoint(s.prevJustifiedCheckpt)
 }

 // HeadSlot returns the slot of the head of the chain.
-func (s *Service) HeadSlot() uint64 {
+func (s *Service) HeadSlot() types.Slot {
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
 	if !s.hasHeadState() {
 		return 0
 	}
@@ -112,12 +111,15 @@ func (s *Service) HeadSlot() uint64 {

 // HeadRoot returns the root of the head of the chain.
 func (s *Service) HeadRoot(ctx context.Context) ([]byte, error) {
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
 	if s.headRoot() != params.BeaconConfig().ZeroHash {
 		r := s.headRoot()
 		return r[:], nil
 	}

-	b, err := s.beaconDB.HeadBlock(ctx)
+	b, err := s.cfg.BeaconDB.HeadBlock(ctx)
 	if err != nil {
 		return nil, err
 	}
@@ -125,7 +127,7 @@ func (s *Service) HeadRoot(ctx context.Context) ([]byte, error) {
 		return params.BeaconConfig().ZeroHash[:], nil
 	}

-	r, err := stateutil.BlockRoot(b.Block)
+	r, err := b.Block.HashTreeRoot()
 	if err != nil {
 		return nil, err
 	}
@@ -137,19 +139,24 @@ func (s *Service) HeadRoot(ctx context.Context) ([]byte, error) {
 // If the head is nil from service struct,
 // it will attempt to get the head block from DB.
 func (s *Service) HeadBlock(ctx context.Context) (*ethpb.SignedBeaconBlock, error) {
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
 	if s.hasHeadState() {
 		return s.headBlock(), nil
 	}

-	return s.beaconDB.HeadBlock(ctx)
+	return s.cfg.BeaconDB.HeadBlock(ctx)
 }

 // HeadState returns the head state of the chain.
 // If the head is nil from service struct,
 // it will attempt to get the head state from DB.
-func (s *Service) HeadState(ctx context.Context) (*state.BeaconState, error) {
-	ctx, span := trace.StartSpan(ctx, "blockchain.HeadState")
+func (s *Service) HeadState(ctx context.Context) (iface.BeaconState, error) {
+	ctx, span := trace.StartSpan(ctx, "blockChain.HeadState")
 	defer span.End()
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()

 	ok := s.hasHeadState()
 	span.AddAttributes(trace.BoolAttribute("cache_hit", ok))
@@ -158,19 +165,25 @@ func (s *Service) HeadState(ctx context.Context) (*state.BeaconState, error) {
 		return s.headState(ctx), nil
 	}

-	return s.beaconDB.HeadState(ctx)
+	return s.cfg.StateGen.StateByRoot(ctx, s.headRoot())
 }

 // HeadValidatorsIndices returns a list of active validator indices from the head view of a given epoch.
-func (s *Service) HeadValidatorsIndices(ctx context.Context, epoch uint64) ([]uint64, error) {
+func (s *Service) HeadValidatorsIndices(ctx context.Context, epoch types.Epoch) ([]types.ValidatorIndex, error) {
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
 	if !s.hasHeadState() {
-		return []uint64{}, nil
+		return []types.ValidatorIndex{}, nil
 	}
 	return helpers.ActiveValidatorIndices(s.headState(ctx), epoch)
 }

 // HeadSeed returns the seed from the head view of a given epoch.
-func (s *Service) HeadSeed(ctx context.Context, epoch uint64) ([32]byte, error) {
+func (s *Service) HeadSeed(ctx context.Context, epoch types.Epoch) ([32]byte, error) {
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
 	if !s.hasHeadState() {
 		return [32]byte{}, nil
 	}
@@ -180,6 +193,9 @@ func (s *Service) HeadSeed(ctx context.Context, epoch uint64) ([32]byte, error)

 // HeadGenesisValidatorRoot returns genesis validator root of the head state.
 func (s *Service) HeadGenesisValidatorRoot() [32]byte {
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
 	if !s.hasHeadState() {
 		return [32]byte{}
 	}
@@ -189,6 +205,9 @@ func (s *Service) HeadGenesisValidatorRoot() [32]byte {

 // HeadETH1Data returns the eth1data of the current head state.
 func (s *Service) HeadETH1Data() *ethpb.Eth1Data {
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
 	if !s.hasHeadState() {
 		return &ethpb.Eth1Data{}
 	}
@@ -197,7 +216,7 @@ func (s *Service) HeadETH1Data() *ethpb.Eth1Data {

 // ProtoArrayStore returns the proto array store object.
 func (s *Service) ProtoArrayStore() *protoarray.Store {
-	return s.forkChoiceStore.Store()
+	return s.cfg.ForkChoiceStore.Store()
 }

 // GenesisTime returns the genesis time of beacon chain.
@@ -208,6 +227,9 @@ func (s *Service) GenesisTime() time.Time {
 // GenesisValidatorRoot returns the genesis validator
 // root of the chain.
 func (s *Service) GenesisValidatorRoot() [32]byte {
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
 	if !s.hasHeadState() {
 		return [32]byte{}
 	}
@@ -216,6 +238,9 @@ func (s *Service) GenesisValidatorRoot() [32]byte {

 // CurrentFork retrieves the latest fork information of the beacon chain.
 func (s *Service) CurrentFork() *pb.Fork {
+	s.headLock.RLock()
+	defer s.headLock.RUnlock()
+
 	if !s.hasHeadState() {
 		return &pb.Fork{
 			PreviousVersion: params.BeaconConfig().GenesisForkVersion,
@@ -225,24 +250,35 @@ func (s *Service) CurrentFork() *pb.Fork {
 	return s.head.state.Fork()
 }

-// Participation returns the participation stats of a given epoch.
-func (s *Service) Participation(epoch uint64) *precompute.Balance {
-	s.epochParticipationLock.RLock()
-	defer s.epochParticipationLock.RUnlock()
-
-	return s.epochParticipation[epoch]
-}
-
 // IsCanonical returns true if the input block root is part of the canonical chain.
 func (s *Service) IsCanonical(ctx context.Context, blockRoot [32]byte) (bool, error) {
 	// If the block has been finalized, the block will always be part of the canonical chain.
-	if s.beaconDB.IsFinalizedBlock(ctx, blockRoot) {
+	if s.cfg.BeaconDB.IsFinalizedBlock(ctx, blockRoot) {
 		return true, nil
 	}

-	// If the block has not been finalized, the block must be recent. Check recent canonical roots
-	// mapping which uses proto array fork choice.
-	s.recentCanonicalBlocksLock.RLock()
-	defer s.recentCanonicalBlocksLock.RUnlock()
-	return s.recentCanonicalBlocks[blockRoot], nil
+	// If the block has not been finalized, check fork choice store to see if the block is canonical
+	return s.cfg.ForkChoiceStore.IsCanonical(blockRoot), nil
+}
+
+// ChainHeads returns all possible chain heads (leaves of fork choice tree).
+// Heads roots and heads slots are returned.
+func (s *Service) ChainHeads() ([][32]byte, []types.Slot) {
+	nodes := s.ProtoArrayStore().Nodes()
+
+	// Deliberate choice to not preallocate space for below.
+	// Heads cant be more than 2-3 in the worst case where pre-allocation will be 64 to begin with.
+	headsRoots := make([][32]byte, 0)
+	headsSlots := make([]types.Slot, 0)
+
+	nonExistentNode := ^uint64(0)
+	for _, node := range nodes {
+		// Possible heads have no children.
+		if node.BestDescendant() == nonExistentNode && node.BestChild() == nonExistentNode {
+			headsRoots = append(headsRoots, node.Root())
+			headsSlots = append(headsSlots, node.Slot())
+		}
+	}
+
+	return headsRoots, headsSlots
 }
--- a/beacon-chain/blockchain/chain_info_norace_test.go
+++ b/beacon-chain/blockchain/chain_info_norace_test.go
@@ -7,67 +7,54 @@ import (
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 )

 func TestHeadSlot_DataRace(t *testing.T) {
-	db, _ := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)
 	s := &Service{
-		beaconDB: db,
+		cfg: &Config{BeaconDB: beaconDB},
 	}
 	go func() {
-		if err := s.saveHead(context.Background(), [32]byte{}); err != nil {
-			t.Fatal(err)
-		}
+		require.NoError(t, s.saveHead(context.Background(), [32]byte{}))
 	}()
 	s.HeadSlot()
 }

 func TestHeadRoot_DataRace(t *testing.T) {
-	db, sc := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)
 	s := &Service{
-		beaconDB: db,
-		head:     &head{root: [32]byte{'A'}},
-		stateGen: stategen.New(db, sc),
+		cfg:  &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)},
+		head: &head{root: [32]byte{'A'}},
 	}
 	go func() {
-		if err := s.saveHead(context.Background(), [32]byte{}); err != nil {
-			t.Fatal(err)
-		}
+		require.NoError(t, s.saveHead(context.Background(), [32]byte{}))
 	}()
-	if _, err := s.HeadRoot(context.Background()); err != nil {
-		t.Fatal(err)
-	}
+	_, err := s.HeadRoot(context.Background())
+	require.NoError(t, err)
 }

 func TestHeadBlock_DataRace(t *testing.T) {
-	db, sc := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)
 	s := &Service{
-		beaconDB: db,
-		head:     &head{block: &ethpb.SignedBeaconBlock{}},
-		stateGen: stategen.New(db, sc),
+		cfg:  &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)},
+		head: &head{block: &ethpb.SignedBeaconBlock{}},
 	}
 	go func() {
-		if err := s.saveHead(context.Background(), [32]byte{}); err != nil {
-			t.Fatal(err)
-		}
+		require.NoError(t, s.saveHead(context.Background(), [32]byte{}))
 	}()
-	if _, err := s.HeadBlock(context.Background()); err != nil {
-		t.Fatal(err)
-	}
+	_, err := s.HeadBlock(context.Background())
+	require.NoError(t, err)
 }

 func TestHeadState_DataRace(t *testing.T) {
-	db, sc := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)
 	s := &Service{
-		beaconDB: db,
-		stateGen: stategen.New(db, sc),
+		cfg: &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)},
 	}
 	go func() {
-		if err := s.saveHead(context.Background(), [32]byte{}); err != nil {
-			t.Fatal(err)
-		}
+		require.NoError(t, s.saveHead(context.Background(), [32]byte{}))
 	}()
-	if _, err := s.HeadState(context.Background()); err != nil {
-		t.Fatal(err)
-	}
+	_, err := s.HeadState(context.Background())
+	require.NoError(t, err)
 }
--- a/beacon-chain/blockchain/chain_info_test.go
+++ b/beacon-chain/blockchain/chain_info_test.go
@@ -1,192 +1,171 @@
 package blockchain

 import (
-	"bytes"
 	"context"
-	"reflect"
 	"testing"
 	"time"

 	"github.com/gogo/protobuf/proto"
+	types "github.com/prysmaticlabs/eth2-types"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
+	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateV0"
 	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 )

 // Ensure Service implements chain info interface.
-var _ = ChainInfoFetcher(&Service{})
-var _ = TimeFetcher(&Service{})
-var _ = ForkFetcher(&Service{})
+var _ ChainInfoFetcher = (*Service)(nil)
+var _ TimeFetcher = (*Service)(nil)
+var _ ForkFetcher = (*Service)(nil)

 func TestFinalizedCheckpt_Nil(t *testing.T) {
-	db, sc := testDB.SetupDB(t)
-	c := setupBeaconChain(t, db, sc)
-	if !bytes.Equal(c.FinalizedCheckpt().Root, params.BeaconConfig().ZeroHash[:]) {
-		t.Error("Incorrect pre chain start value")
-	}
+	beaconDB := testDB.SetupDB(t)
+	c := setupBeaconChain(t, beaconDB)
+	assert.DeepEqual(t, params.BeaconConfig().ZeroHash[:], c.FinalizedCheckpt().Root, "Incorrect pre chain start value")
 }

 func TestHeadRoot_Nil(t *testing.T) {
-	db, sc := testDB.SetupDB(t)
-	c := setupBeaconChain(t, db, sc)
+	beaconDB := testDB.SetupDB(t)
+	c := setupBeaconChain(t, beaconDB)
 	headRoot, err := c.HeadRoot(context.Background())
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !bytes.Equal(headRoot, params.BeaconConfig().ZeroHash[:]) {
-		t.Error("Incorrect pre chain start value")
-	}
+	require.NoError(t, err)
+	assert.DeepEqual(t, params.BeaconConfig().ZeroHash[:], headRoot, "Incorrect pre chain start value")
 }

 func TestFinalizedCheckpt_CanRetrieve(t *testing.T) {
-	db, sc := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)

-	cp := &ethpb.Checkpoint{Epoch: 5, Root: []byte("foo")}
-	c := setupBeaconChain(t, db, sc)
+	cp := &ethpb.Checkpoint{Epoch: 5, Root: bytesutil.PadTo([]byte("foo"), 32)}
+	c := setupBeaconChain(t, beaconDB)
 	c.finalizedCheckpt = cp

-	if c.FinalizedCheckpt().Epoch != cp.Epoch {
-		t.Errorf("Finalized epoch at genesis should be %d, got: %d", cp.Epoch, c.FinalizedCheckpt().Epoch)
-	}
+	assert.Equal(t, cp.Epoch, c.FinalizedCheckpt().Epoch, "Unexpected finalized epoch")
 }

 func TestFinalizedCheckpt_GenesisRootOk(t *testing.T) {
-	db, sc := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)

 	genesisRoot := [32]byte{'A'}
 	cp := &ethpb.Checkpoint{Root: genesisRoot[:]}
-	c := setupBeaconChain(t, db, sc)
+	c := setupBeaconChain(t, beaconDB)
 	c.finalizedCheckpt = cp
 	c.genesisRoot = genesisRoot
-
-	if !bytes.Equal(c.FinalizedCheckpt().Root, c.genesisRoot[:]) {
-		t.Errorf("Got: %v, wanted: %v", c.FinalizedCheckpt().Root, c.genesisRoot[:])
-	}
+	assert.DeepEqual(t, c.genesisRoot[:], c.FinalizedCheckpt().Root)
 }

 func TestCurrentJustifiedCheckpt_CanRetrieve(t *testing.T) {
-	db, sc := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)

-	cp := &ethpb.Checkpoint{Epoch: 6, Root: []byte("foo")}
-	c := setupBeaconChain(t, db, sc)
+	c := setupBeaconChain(t, beaconDB)
+	assert.Equal(t, params.BeaconConfig().ZeroHash, bytesutil.ToBytes32(c.CurrentJustifiedCheckpt().Root), "Unexpected justified epoch")
+	cp := &ethpb.Checkpoint{Epoch: 6, Root: bytesutil.PadTo([]byte("foo"), 32)}
 	c.justifiedCheckpt = cp
-
-	if c.CurrentJustifiedCheckpt().Epoch != cp.Epoch {
-		t.Errorf("Current Justifiied epoch at genesis should be %d, got: %d", cp.Epoch, c.CurrentJustifiedCheckpt().Epoch)
-	}
+	assert.Equal(t, cp.Epoch, c.CurrentJustifiedCheckpt().Epoch, "Unexpected justified epoch")
 }

 func TestJustifiedCheckpt_GenesisRootOk(t *testing.T) {
-	db, sc := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)

+	c := setupBeaconChain(t, beaconDB)
 	genesisRoot := [32]byte{'B'}
 	cp := &ethpb.Checkpoint{Root: genesisRoot[:]}
-	c := setupBeaconChain(t, db, sc)
 	c.justifiedCheckpt = cp
 	c.genesisRoot = genesisRoot
-
-	if !bytes.Equal(c.CurrentJustifiedCheckpt().Root, c.genesisRoot[:]) {
-		t.Errorf("Got: %v, wanted: %v", c.CurrentJustifiedCheckpt().Root, c.genesisRoot[:])
-	}
+	assert.DeepEqual(t, c.genesisRoot[:], c.CurrentJustifiedCheckpt().Root)
 }

 func TestPreviousJustifiedCheckpt_CanRetrieve(t *testing.T) {
-	db, sc := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)

-	cp := &ethpb.Checkpoint{Epoch: 7, Root: []byte("foo")}
-	c := setupBeaconChain(t, db, sc)
+	cp := &ethpb.Checkpoint{Epoch: 7, Root: bytesutil.PadTo([]byte("foo"), 32)}
+	c := setupBeaconChain(t, beaconDB)
+	assert.Equal(t, params.BeaconConfig().ZeroHash, bytesutil.ToBytes32(c.CurrentJustifiedCheckpt().Root), "Unexpected justified epoch")
 	c.prevJustifiedCheckpt = cp
-
-	if c.PreviousJustifiedCheckpt().Epoch != cp.Epoch {
-		t.Errorf("Previous Justifiied epoch at genesis should be %d, got: %d", cp.Epoch, c.PreviousJustifiedCheckpt().Epoch)
-	}
+	assert.Equal(t, cp.Epoch, c.PreviousJustifiedCheckpt().Epoch, "Unexpected previous justified epoch")
 }

 func TestPrevJustifiedCheckpt_GenesisRootOk(t *testing.T) {
-	db, sc := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)

 	genesisRoot := [32]byte{'C'}
 	cp := &ethpb.Checkpoint{Root: genesisRoot[:]}
-	c := setupBeaconChain(t, db, sc)
+	c := setupBeaconChain(t, beaconDB)
 	c.prevJustifiedCheckpt = cp
 	c.genesisRoot = genesisRoot
-
-	if !bytes.Equal(c.PreviousJustifiedCheckpt().Root, c.genesisRoot[:]) {
-		t.Errorf("Got: %v, wanted: %v", c.PreviousJustifiedCheckpt().Root, c.genesisRoot[:])
-	}
+	assert.DeepEqual(t, c.genesisRoot[:], c.PreviousJustifiedCheckpt().Root)
 }

 func TestHeadSlot_CanRetrieve(t *testing.T) {
 	c := &Service{}
-	s, err := state.InitializeFromProto(&pb.BeaconState{})
-	if err != nil {
-		t.Fatal(err)
-	}
+	s, err := stateV0.InitializeFromProto(&pb.BeaconState{})
+	require.NoError(t, err)
 	c.head = &head{slot: 100, state: s}
-	if c.HeadSlot() != 100 {
-		t.Errorf("Wanted head slot: %d, got: %d", 100, c.HeadSlot())
-	}
+	assert.Equal(t, types.Slot(100), c.HeadSlot())
 }

 func TestHeadRoot_CanRetrieve(t *testing.T) {
 	c := &Service{}
 	c.head = &head{root: [32]byte{'A'}}
-	if [32]byte{'A'} != c.headRoot() {
-		t.Errorf("Wanted head root: %v, got: %d", []byte{'A'}, c.headRoot())
-	}
+	r, err := c.HeadRoot(context.Background())
+	require.NoError(t, err)
+	assert.Equal(t, [32]byte{'A'}, bytesutil.ToBytes32(r))
+}
+
+func TestHeadRoot_UseDB(t *testing.T) {
+	beaconDB := testDB.SetupDB(t)
+	c := &Service{cfg: &Config{BeaconDB: beaconDB}}
+	c.head = &head{root: params.BeaconConfig().ZeroHash}
+	b := testutil.NewBeaconBlock()
+	br, err := b.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveBlock(context.Background(), b))
+	require.NoError(t, beaconDB.SaveStateSummary(context.Background(), &pb.StateSummary{Root: br[:]}))
+	require.NoError(t, beaconDB.SaveHeadBlockRoot(context.Background(), br))
+	r, err := c.HeadRoot(context.Background())
+	require.NoError(t, err)
+	assert.Equal(t, br, bytesutil.ToBytes32(r))
 }

 func TestHeadBlock_CanRetrieve(t *testing.T) {
-	b := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Slot: 1}}
-	s, err := state.InitializeFromProto(&pb.BeaconState{})
-	if err != nil {
-		t.Fatal(err)
-	}
+	b := testutil.NewBeaconBlock()
+	b.Block.Slot = 1
+	s, err := stateV0.InitializeFromProto(&pb.BeaconState{})
+	require.NoError(t, err)
 	c := &Service{}
 	c.head = &head{block: b, state: s}

 	recevied, err := c.HeadBlock(context.Background())
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	if !reflect.DeepEqual(b, recevied) {
-		t.Error("incorrect head block received")
-	}
+	require.NoError(t, err)
+	assert.DeepEqual(t, b, recevied, "Incorrect head block received")
 }

 func TestHeadState_CanRetrieve(t *testing.T) {
-	s, err := state.InitializeFromProto(&pb.BeaconState{Slot: 2, GenesisValidatorsRoot: params.BeaconConfig().ZeroHash[:]})
-	if err != nil {
-		t.Fatal(err)
-	}
+	s, err := stateV0.InitializeFromProto(&pb.BeaconState{Slot: 2, GenesisValidatorsRoot: params.BeaconConfig().ZeroHash[:]})
+	require.NoError(t, err)
 	c := &Service{}
 	c.head = &head{state: s}
 	headState, err := c.HeadState(context.Background())
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !proto.Equal(s.InnerStateUnsafe(), headState.InnerStateUnsafe()) {
-		t.Error("incorrect head state received")
-	}
+	require.NoError(t, err)
+	assert.DeepEqual(t, headState.InnerStateUnsafe(), s.InnerStateUnsafe(), "Incorrect head state received")
 }

 func TestGenesisTime_CanRetrieve(t *testing.T) {
 	c := &Service{genesisTime: time.Unix(999, 0)}
 	wanted := time.Unix(999, 0)
-	if c.GenesisTime() != wanted {
-		t.Error("Did not get wanted genesis time")
-	}
+	assert.Equal(t, wanted, c.GenesisTime(), "Did not get wanted genesis time")
 }

 func TestCurrentFork_CanRetrieve(t *testing.T) {
 	f := &pb.Fork{Epoch: 999}
-	s, err := state.InitializeFromProto(&pb.BeaconState{Fork: f})
-	if err != nil {
-		t.Fatal(err)
-	}
+	s, err := stateV0.InitializeFromProto(&pb.BeaconState{Fork: f})
+	require.NoError(t, err)
 	c := &Service{}
 	c.head = &head{state: s}
 	if !proto.Equal(c.CurrentFork(), f) {
@@ -194,40 +173,126 @@ func TestCurrentFork_CanRetrieve(t *testing.T) {
 	}
 }

+func TestCurrentFork_NilHeadSTate(t *testing.T) {
+	f := &pb.Fork{
+		PreviousVersion: params.BeaconConfig().GenesisForkVersion,
+		CurrentVersion:  params.BeaconConfig().GenesisForkVersion,
+	}
+	c := &Service{}
+	if !proto.Equal(c.CurrentFork(), f) {
+		t.Error("Received incorrect fork version")
+	}
+}
+
 func TestGenesisValidatorRoot_CanRetrieve(t *testing.T) {
 	// Should not panic if head state is nil.
 	c := &Service{}
-	if c.GenesisValidatorRoot() != [32]byte{} {
-		t.Error("Did not get correct genesis validator root")
-	}
+	assert.Equal(t, [32]byte{}, c.GenesisValidatorRoot(), "Did not get correct genesis validator root")

-	s, err := state.InitializeFromProto(&pb.BeaconState{GenesisValidatorsRoot: []byte{'a'}})
-	if err != nil {
-		t.Fatal(err)
-	}
+	s, err := stateV0.InitializeFromProto(&pb.BeaconState{GenesisValidatorsRoot: []byte{'a'}})
+	require.NoError(t, err)
 	c.head = &head{state: s}
-	if c.GenesisValidatorRoot() != [32]byte{'a'} {
-		t.Error("Did not get correct genesis validator root")
-	}
+	assert.Equal(t, [32]byte{'a'}, c.GenesisValidatorRoot(), "Did not get correct genesis validator root")
 }

 func TestHeadETH1Data_Nil(t *testing.T) {
-	db, sc := testDB.SetupDB(t)
-	c := setupBeaconChain(t, db, sc)
-	if !reflect.DeepEqual(c.HeadETH1Data(), &ethpb.Eth1Data{}) {
-		t.Error("Incorrect pre chain start value")
-	}
+	beaconDB := testDB.SetupDB(t)
+	c := setupBeaconChain(t, beaconDB)
+	assert.DeepEqual(t, &ethpb.Eth1Data{}, c.HeadETH1Data(), "Incorrect pre chain start value")
 }

 func TestHeadETH1Data_CanRetrieve(t *testing.T) {
 	d := &ethpb.Eth1Data{DepositCount: 999}
-	s, err := state.InitializeFromProto(&pb.BeaconState{Eth1Data: d})
-	if err != nil {
-		t.Fatal(err)
-	}
+	s, err := stateV0.InitializeFromProto(&pb.BeaconState{Eth1Data: d})
+	require.NoError(t, err)
 	c := &Service{}
 	c.head = &head{state: s}
 	if !proto.Equal(c.HeadETH1Data(), d) {
 		t.Error("Received incorrect eth1 data")
 	}
 }
+
+func TestIsCanonical_Ok(t *testing.T) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+	c := setupBeaconChain(t, beaconDB)
+
+	blk := testutil.NewBeaconBlock()
+	blk.Block.Slot = 0
+	root, err := blk.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveBlock(ctx, blk))
+	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, root))
+	can, err := c.IsCanonical(ctx, root)
+	require.NoError(t, err)
+	assert.Equal(t, true, can)
+
+	can, err = c.IsCanonical(ctx, [32]byte{'a'})
+	require.NoError(t, err)
+	assert.Equal(t, false, can)
+}
+
+func TestService_HeadValidatorsIndices(t *testing.T) {
+	s, _ := testutil.DeterministicGenesisState(t, 10)
+	c := &Service{}
+
+	c.head = &head{}
+	indices, err := c.HeadValidatorsIndices(context.Background(), 0)
+	require.NoError(t, err)
+	require.Equal(t, 0, len(indices))
+
+	c.head = &head{state: s}
+	indices, err = c.HeadValidatorsIndices(context.Background(), 0)
+	require.NoError(t, err)
+	require.Equal(t, 10, len(indices))
+}
+
+func TestService_HeadSeed(t *testing.T) {
+	s, _ := testutil.DeterministicGenesisState(t, 1)
+	c := &Service{}
+	seed, err := helpers.Seed(s, 0, params.BeaconConfig().DomainBeaconAttester)
+	require.NoError(t, err)
+
+	c.head = &head{}
+	root, err := c.HeadSeed(context.Background(), 0)
+	require.NoError(t, err)
+	require.Equal(t, [32]byte{}, root)
+
+	c.head = &head{state: s}
+	root, err = c.HeadSeed(context.Background(), 0)
+	require.NoError(t, err)
+	require.DeepEqual(t, seed, root)
+}
+
+func TestService_HeadGenesisValidatorRoot(t *testing.T) {
+	s, _ := testutil.DeterministicGenesisState(t, 1)
+	c := &Service{}
+
+	c.head = &head{}
+	root := c.HeadGenesisValidatorRoot()
+	require.Equal(t, [32]byte{}, root)
+
+	c.head = &head{state: s}
+	root = c.HeadGenesisValidatorRoot()
+	require.DeepEqual(t, root[:], s.GenesisValidatorRoot())
+}
+
+func TestService_ProtoArrayStore(t *testing.T) {
+	c := &Service{cfg: &Config{ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}}
+	p := c.ProtoArrayStore()
+	require.Equal(t, 0, int(p.FinalizedEpoch()))
+}
+
+func TestService_ChainHeads(t *testing.T) {
+	ctx := context.Background()
+	c := &Service{cfg: &Config{ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}}
+	require.NoError(t, c.cfg.ForkChoiceStore.ProcessBlock(ctx, 100, [32]byte{'a'}, [32]byte{}, [32]byte{}, 0, 0))
+	require.NoError(t, c.cfg.ForkChoiceStore.ProcessBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, [32]byte{}, 0, 0))
+	require.NoError(t, c.cfg.ForkChoiceStore.ProcessBlock(ctx, 102, [32]byte{'c'}, [32]byte{'b'}, [32]byte{}, 0, 0))
+	require.NoError(t, c.cfg.ForkChoiceStore.ProcessBlock(ctx, 103, [32]byte{'d'}, [32]byte{}, [32]byte{}, 0, 0))
+	require.NoError(t, c.cfg.ForkChoiceStore.ProcessBlock(ctx, 104, [32]byte{'e'}, [32]byte{'b'}, [32]byte{}, 0, 0))
+
+	roots, slots := c.ChainHeads()
+	require.DeepEqual(t, [][32]byte{{'c'}, {'d'}, {'e'}}, roots)
+	require.DeepEqual(t, []types.Slot{102, 103, 104}, slots)
+}
--- a/beacon-chain/blockchain/checktags_test.go
+++ b/beacon-chain/blockchain/checktags_test.go
@@ -0,0 +1,7 @@
+// +build !develop
+
+package blockchain
+
+func init() {
+	log.Fatal("Tests in this package require extra build tag: re-run with `-tags develop`")
+}
--- a/beacon-chain/blockchain/head.go
+++ b/beacon-chain/blockchain/head.go
@@ -1,17 +1,19 @@
 package blockchain

 import (
+	"bytes"
 	"context"
 	"fmt"

 	"github.com/pkg/errors"
+	types "github.com/prysmaticlabs/eth2-types"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/feed"
 	statefeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateV0"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/sirupsen/logrus"
@@ -20,16 +22,16 @@ import (

 // This defines the current chain service's view of head.
 type head struct {
-	slot  uint64                   // current head slot.
+	slot  types.Slot               // current head slot.
 	root  [32]byte                 // current head root.
 	block *ethpb.SignedBeaconBlock // current head block.
-	state *state.BeaconState       // current head state.
+	state iface.BeaconState        // current head state.
 }

 // Determined the head from the fork choice service and saves its new data
 // (head root, head block, and head state) to the local service cache.
 func (s *Service) updateHead(ctx context.Context, balances []uint64) error {
-	ctx, span := trace.StartSpan(ctx, "blockchain.updateHead")
+	ctx, span := trace.StartSpan(ctx, "blockChain.updateHead")
 	defer span.End()

 	// To get the proper head update, a node first checks its best justified
@@ -51,12 +53,24 @@ func (s *Service) updateHead(ctx context.Context, balances []uint64) error {
 	if headStartRoot == params.BeaconConfig().ZeroHash {
 		headStartRoot = s.genesisRoot
 	}
-	headRoot, err := s.forkChoiceStore.Head(ctx, j.Epoch, headStartRoot, balances, f.Epoch)
-	if err != nil {
-		return err
+
+	// In order to process head, fork choice store requires justified info.
+	// If the fork choice store is missing justified block info, a node should
+	// re-initiate fork choice store using the latest justified info.
+	// This recovers a fatal condition and should not happen in run time.
+	if !s.cfg.ForkChoiceStore.HasNode(headStartRoot) {
+		jb, err := s.cfg.BeaconDB.Block(ctx, headStartRoot)
+		if err != nil {
+			return err
+		}
+		s.cfg.ForkChoiceStore = protoarray.New(j.Epoch, f.Epoch, bytesutil.ToBytes32(f.Root))
+		if err := s.insertBlockToForkChoiceStore(ctx, jb.Block, headStartRoot, f, j); err != nil {
+			return err
+		}
 	}

-	if err := s.updateRecentCanonicalBlocks(ctx, headRoot); err != nil {
+	headRoot, err := s.cfg.ForkChoiceStore.Head(ctx, j.Epoch, headStartRoot, balances, f.Epoch)
+	if err != nil {
 		return err
 	}

@@ -67,22 +81,26 @@ func (s *Service) updateHead(ctx context.Context, balances []uint64) error {
 // This saves head info to the local service cache, it also saves the
 // new head root to the DB.
 func (s *Service) saveHead(ctx context.Context, headRoot [32]byte) error {
-	ctx, span := trace.StartSpan(ctx, "blockchain.saveHead")
+	ctx, span := trace.StartSpan(ctx, "blockChain.saveHead")
 	defer span.End()

 	// Do nothing if head hasn't changed.
-	if headRoot == s.headRoot() {
+	r, err := s.HeadRoot(ctx)
+	if err != nil {
+		return err
+	}
+	if headRoot == bytesutil.ToBytes32(r) {
 		return nil
 	}

 	// If the head state is not available, just return nil.
 	// There's nothing to cache
-	if !s.stateGen.StateSummaryExists(ctx, headRoot) {
+	if !s.cfg.BeaconDB.HasStateSummary(ctx, headRoot) {
 		return nil
 	}

 	// Get the new head block from DB.
-	newHeadBlock, err := s.beaconDB.Block(ctx, headRoot)
+	newHeadBlock, err := s.cfg.BeaconDB.Block(ctx, headRoot)
 	if err != nil {
 		return err
 	}
@@ -91,7 +109,7 @@ func (s *Service) saveHead(ctx context.Context, headRoot [32]byte) error {
 	}

 	// Get the new head state from cached state or DB.
-	newHeadState, err := s.stateGen.StateByRoot(ctx, headRoot)
+	newHeadState, err := s.cfg.StateGen.StateByRoot(ctx, headRoot)
 	if err != nil {
 		return errors.Wrap(err, "could not retrieve head state in DB")
 	}
@@ -100,16 +118,17 @@ func (s *Service) saveHead(ctx context.Context, headRoot [32]byte) error {
 	}

 	// A chain re-org occurred, so we fire an event notifying the rest of the services.
-	if bytesutil.ToBytes32(newHeadBlock.Block.ParentRoot) != s.headRoot() {
+	headSlot := s.HeadSlot()
+	if bytesutil.ToBytes32(newHeadBlock.Block.ParentRoot) != bytesutil.ToBytes32(r) {
 		log.WithFields(logrus.Fields{
 			"newSlot": fmt.Sprintf("%d", newHeadBlock.Block.Slot),
-			"oldSlot": fmt.Sprintf("%d", s.headSlot()),
+			"oldSlot": fmt.Sprintf("%d", headSlot),
 		}).Debug("Chain reorg occurred")
-		s.stateNotifier.StateFeed().Send(&feed.Event{
+		s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
 			Type: statefeed.Reorg,
 			Data: &statefeed.ReorgData{
 				NewSlot: newHeadBlock.Block.Slot,
-				OldSlot: s.headSlot(),
+				OldSlot: headSlot,
 			},
 		})

@@ -120,7 +139,7 @@ func (s *Service) saveHead(ctx context.Context, headRoot [32]byte) error {
 	s.setHead(headRoot, newHeadBlock, newHeadState)

 	// Save the new head root to DB.
-	if err := s.beaconDB.SaveHeadBlockRoot(ctx, headRoot); err != nil {
+	if err := s.cfg.BeaconDB.SaveHeadBlockRoot(ctx, headRoot); err != nil {
 		return errors.Wrap(err, "could not save head root in DB")
 	}

@@ -130,26 +149,24 @@ func (s *Service) saveHead(ctx context.Context, headRoot [32]byte) error {
 // This gets called to update canonical root mapping. It does not save head block
 // root in DB. With the inception of initial-sync-cache-state flag, it uses finalized
 // check point as anchors to resume sync therefore head is no longer needed to be saved on per slot basis.
-func (s *Service) saveHeadNoDB(ctx context.Context, b *ethpb.SignedBeaconBlock, r [32]byte) error {
-	if b == nil || b.Block == nil {
-		return errors.New("cannot save nil head block")
+func (s *Service) saveHeadNoDB(ctx context.Context, b *ethpb.SignedBeaconBlock, r [32]byte, hs iface.BeaconState) error {
+	if err := helpers.VerifyNilBeaconBlock(b); err != nil {
+		return err
 	}
-
-	headState, err := s.stateGen.StateByRootInitialSync(ctx, r)
+	cachedHeadRoot, err := s.HeadRoot(ctx)
 	if err != nil {
-		return errors.Wrap(err, "could not retrieve head state in DB")
+		return errors.Wrap(err, "could not get head root from cache")
 	}
-	if headState == nil {
-		return errors.New("nil head state")
+	if bytes.Equal(r[:], cachedHeadRoot) {
+		return nil
 	}

-	s.setHeadInitialSync(r, stateTrie.CopySignedBeaconBlock(b), headState)
-
+	s.setHeadInitialSync(r, stateV0.CopySignedBeaconBlock(b), hs)
 	return nil
 }

 // This sets head view object which is used to track the head slot, root, block and state.
-func (s *Service) setHead(root [32]byte, block *ethpb.SignedBeaconBlock, state *state.BeaconState) {
+func (s *Service) setHead(root [32]byte, block *ethpb.SignedBeaconBlock, state iface.BeaconState) {
 	s.headLock.Lock()
 	defer s.headLock.Unlock()

@@ -157,7 +174,7 @@ func (s *Service) setHead(root [32]byte, block *ethpb.SignedBeaconBlock, state *
 	s.head = &head{
 		slot:  block.Block.Slot,
 		root:  root,
-		block: stateTrie.CopySignedBeaconBlock(block),
+		block: stateV0.CopySignedBeaconBlock(block),
 		state: state.Copy(),
 	}
 }
@@ -165,7 +182,7 @@ func (s *Service) setHead(root [32]byte, block *ethpb.SignedBeaconBlock, state *
 // This sets head view object which is used to track the head slot, root, block and state. The method
 // assumes that state being passed into the method will not be modified by any other alternate
 // caller which holds the state's reference.
-func (s *Service) setHeadInitialSync(root [32]byte, block *ethpb.SignedBeaconBlock, state *state.BeaconState) {
+func (s *Service) setHeadInitialSync(root [32]byte, block *ethpb.SignedBeaconBlock, state iface.BeaconState) {
 	s.headLock.Lock()
 	defer s.headLock.Unlock()

@@ -173,118 +190,94 @@ func (s *Service) setHeadInitialSync(root [32]byte, block *ethpb.SignedBeaconBlo
 	s.head = &head{
 		slot:  block.Block.Slot,
 		root:  root,
-		block: stateTrie.CopySignedBeaconBlock(block),
+		block: stateV0.CopySignedBeaconBlock(block),
 		state: state,
 	}
 }

 // This returns the head slot.
-func (s *Service) headSlot() uint64 {
-	s.headLock.RLock()
-	defer s.headLock.RUnlock()
-
+// This is a lock free version.
+func (s *Service) headSlot() types.Slot {
 	return s.head.slot
 }

 // This returns the head root.
 // It does a full copy on head root for immutability.
+// This is a lock free version.
 func (s *Service) headRoot() [32]byte {
 	if s.head == nil {
 		return params.BeaconConfig().ZeroHash
 	}

-	s.headLock.RLock()
-	defer s.headLock.RUnlock()
-
 	return s.head.root
 }

 // This returns the head block.
 // It does a full copy on head block for immutability.
+// This is a lock free version.
 func (s *Service) headBlock() *ethpb.SignedBeaconBlock {
-	s.headLock.RLock()
-	defer s.headLock.RUnlock()
-
-	return stateTrie.CopySignedBeaconBlock(s.head.block)
+	return stateV0.CopySignedBeaconBlock(s.head.block)
 }

 // This returns the head state.
 // It does a full copy on head state for immutability.
-func (s *Service) headState(ctx context.Context) *stateTrie.BeaconState {
-	ctx, span := trace.StartSpan(ctx, "blockchain.headState")
+// This is a lock free version.
+func (s *Service) headState(ctx context.Context) iface.BeaconState {
+	ctx, span := trace.StartSpan(ctx, "blockChain.headState")
 	defer span.End()

-	s.headLock.RLock()
-	defer s.headLock.RUnlock()
-
 	return s.head.state.Copy()
 }

 // This returns the genesis validator root of the head state.
+// This is a lock free version.
 func (s *Service) headGenesisValidatorRoot() [32]byte {
-	s.headLock.RLock()
-	defer s.headLock.RUnlock()
-
 	return bytesutil.ToBytes32(s.head.state.GenesisValidatorRoot())
 }

 // Returns true if head state exists.
+// This is the lock free version.
 func (s *Service) hasHeadState() bool {
-	s.headLock.RLock()
-	defer s.headLock.RUnlock()
-
 	return s.head != nil && s.head.state != nil
 }

-// This updates recent canonical block mapping. It uses input head root and retrieves
-// all the canonical block roots that are ancestor of the input head block root.
-func (s *Service) updateRecentCanonicalBlocks(ctx context.Context, headRoot [32]byte) error {
-	ctx, span := trace.StartSpan(ctx, "blockchain.updateRecentCanonicalBlocks")
-	defer span.End()
-
-	s.recentCanonicalBlocksLock.Lock()
-	defer s.recentCanonicalBlocksLock.Unlock()
-
-	s.recentCanonicalBlocks = make(map[[32]byte]bool)
-	s.recentCanonicalBlocks[headRoot] = true
-	nodes := s.forkChoiceStore.Nodes()
-	node := s.forkChoiceStore.Node(headRoot)
-	if node == nil {
-		return nil
-	}
-
-	for node.Parent != protoarray.NonExistentNode {
-		if ctx.Err() != nil {
-			return ctx.Err()
-		}
-		node = nodes[node.Parent]
-		s.recentCanonicalBlocks[node.Root] = true
-	}
-
-	return nil
-}
-
 // This caches justified state balances to be used for fork choice.
 func (s *Service) cacheJustifiedStateBalances(ctx context.Context, justifiedRoot [32]byte) error {
-	if err := s.beaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
+	if err := s.cfg.BeaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
 		return err
 	}

 	s.clearInitSyncBlocks()
-	justifiedState, err := s.stateGen.StateByRoot(ctx, justifiedRoot)
-	if err != nil {
-		return err
+
+	var justifiedState iface.BeaconState
+	var err error
+	if justifiedRoot == s.genesisRoot {
+		justifiedState, err = s.cfg.BeaconDB.GenesisState(ctx)
+		if err != nil {
+			return err
+		}
+	} else {
+		justifiedState, err = s.cfg.StateGen.StateByRoot(ctx, justifiedRoot)
+		if err != nil {
+			return err
+		}
+	}
+	if justifiedState == nil {
+		return errors.New("justified state can't be nil")
 	}

 	epoch := helpers.CurrentEpoch(justifiedState)
-	validators := justifiedState.Validators()
-	justifiedBalances := make([]uint64, len(validators))
-	for i, validator := range validators {
-		if helpers.IsActiveValidator(validator, epoch) {
-			justifiedBalances[i] = validator.EffectiveBalance
+
+	justifiedBalances := make([]uint64, justifiedState.NumValidators())
+	if err := justifiedState.ReadFromEveryValidator(func(idx int, val iface.ReadOnlyValidator) error {
+		if helpers.IsActiveValidatorUsingTrie(val, epoch) {
+			justifiedBalances[idx] = val.EffectiveBalance()
 		} else {
-			justifiedBalances[i] = 0
+			justifiedBalances[idx] = 0
 		}
+		return nil
+	}); err != nil {
+		return err
 	}

 	s.justifiedBalancesLock.Lock()
--- a/beacon-chain/blockchain/head_test.go
+++ b/beacon-chain/blockchain/head_test.go
@@ -3,220 +3,122 @@ package blockchain
 import (
 	"bytes"
 	"context"
-	"reflect"
 	"testing"

+	types "github.com/prysmaticlabs/eth2-types"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateutil"
 	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
 	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 	logTest "github.com/sirupsen/logrus/hooks/test"
 )

 func TestSaveHead_Same(t *testing.T) {
-	db, sc := testDB.SetupDB(t)
-	service := setupBeaconChain(t, db, sc)
+	beaconDB := testDB.SetupDB(t)
+	service := setupBeaconChain(t, beaconDB)

 	r := [32]byte{'A'}
 	service.head = &head{slot: 0, root: r}

-	if err := service.saveHead(context.Background(), r); err != nil {
-		t.Fatal(err)
-	}
-
-	if service.headSlot() != 0 {
-		t.Error("Head did not stay the same")
-	}
-
-	if service.headRoot() != r {
-		t.Error("Head did not stay the same")
-	}
+	require.NoError(t, service.saveHead(context.Background(), r))
+	assert.Equal(t, types.Slot(0), service.headSlot(), "Head did not stay the same")
+	assert.Equal(t, r, service.headRoot(), "Head did not stay the same")
 }

 func TestSaveHead_Different(t *testing.T) {
 	ctx := context.Background()
-	db, sc := testDB.SetupDB(t)
-	service := setupBeaconChain(t, db, sc)
+	beaconDB := testDB.SetupDB(t)
+	service := setupBeaconChain(t, beaconDB)

 	oldRoot := [32]byte{'A'}
 	service.head = &head{slot: 0, root: oldRoot}

-	newHeadBlock := &ethpb.BeaconBlock{Slot: 1}
-	newHeadSignedBlock := &ethpb.SignedBeaconBlock{Block: newHeadBlock}
+	newHeadSignedBlock := testutil.NewBeaconBlock()
+	newHeadSignedBlock.Block.Slot = 1
+	newHeadBlock := newHeadSignedBlock.Block

-	if err := service.beaconDB.SaveBlock(context.Background(), newHeadSignedBlock); err != nil {
-		t.Fatal(err)
-	}
-	newRoot, err := stateutil.BlockRoot(newHeadBlock)
-	if err != nil {
-		t.Fatal(err)
-	}
-	headState := testutil.NewBeaconState()
-	if err := headState.SetSlot(1); err != nil {
-		t.Fatal(err)
-	}
-	if err := service.beaconDB.SaveStateSummary(context.Background(), &pb.StateSummary{Slot: 1, Root: newRoot[:]}); err != nil {
-		t.Fatal(err)
-	}
-	if err := service.beaconDB.SaveState(context.Background(), headState, newRoot); err != nil {
-		t.Fatal(err)
-	}
-	if err := service.saveHead(context.Background(), newRoot); err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(context.Background(), newHeadSignedBlock))
+	newRoot, err := newHeadBlock.HashTreeRoot()
+	require.NoError(t, err)
+	headState, err := testutil.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, headState.SetSlot(1))
+	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(context.Background(), &pb.StateSummary{Slot: 1, Root: newRoot[:]}))
+	require.NoError(t, service.cfg.BeaconDB.SaveState(context.Background(), headState, newRoot))
+	require.NoError(t, service.saveHead(context.Background(), newRoot))

-	if service.HeadSlot() != 1 {
-		t.Error("Head did not change")
-	}
+	assert.Equal(t, types.Slot(1), service.HeadSlot(), "Head did not change")

 	cachedRoot, err := service.HeadRoot(context.Background())
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !bytes.Equal(cachedRoot, newRoot[:]) {
-		t.Error("Head did not change")
-	}
-	if !reflect.DeepEqual(service.headBlock(), newHeadSignedBlock) {
-		t.Error("Head did not change")
-	}
-	if !reflect.DeepEqual(service.headState(ctx).CloneInnerState(), headState.CloneInnerState()) {
-		t.Error("Head did not change")
-	}
+	require.NoError(t, err)
+	assert.DeepEqual(t, cachedRoot, newRoot[:], "Head did not change")
+	assert.DeepEqual(t, newHeadSignedBlock, service.headBlock(), "Head did not change")
+	assert.DeepSSZEqual(t, headState.CloneInnerState(), service.headState(ctx).CloneInnerState(), "Head did not change")
 }

 func TestSaveHead_Different_Reorg(t *testing.T) {
 	ctx := context.Background()
 	hook := logTest.NewGlobal()
-	db, sc := testDB.SetupDB(t)
-	service := setupBeaconChain(t, db, sc)
+	beaconDB := testDB.SetupDB(t)
+	service := setupBeaconChain(t, beaconDB)

 	oldRoot := [32]byte{'A'}
 	service.head = &head{slot: 0, root: oldRoot}

 	reorgChainParent := [32]byte{'B'}
-	newHeadBlock := &ethpb.BeaconBlock{
-		Slot:       1,
-		ParentRoot: reorgChainParent[:],
-	}
-	newHeadSignedBlock := &ethpb.SignedBeaconBlock{Block: newHeadBlock}
+	newHeadSignedBlock := testutil.NewBeaconBlock()
+	newHeadSignedBlock.Block.Slot = 1
+	newHeadSignedBlock.Block.ParentRoot = reorgChainParent[:]
+	newHeadBlock := newHeadSignedBlock.Block

-	if err := service.beaconDB.SaveBlock(context.Background(), newHeadSignedBlock); err != nil {
-		t.Fatal(err)
-	}
-	newRoot, err := stateutil.BlockRoot(newHeadBlock)
-	if err != nil {
-		t.Fatal(err)
-	}
-	headState := testutil.NewBeaconState()
-	if err := headState.SetSlot(1); err != nil {
-		t.Fatal(err)
-	}
-	if err := service.beaconDB.SaveStateSummary(context.Background(), &pb.StateSummary{Slot: 1, Root: newRoot[:]}); err != nil {
-		t.Fatal(err)
-	}
-	if err := service.beaconDB.SaveState(context.Background(), headState, newRoot); err != nil {
-		t.Fatal(err)
-	}
-	if err := service.saveHead(context.Background(), newRoot); err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(context.Background(), newHeadSignedBlock))
+	newRoot, err := newHeadBlock.HashTreeRoot()
+	require.NoError(t, err)
+	headState, err := testutil.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, headState.SetSlot(1))
+	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(context.Background(), &pb.StateSummary{Slot: 1, Root: newRoot[:]}))
+	require.NoError(t, service.cfg.BeaconDB.SaveState(context.Background(), headState, newRoot))
+	require.NoError(t, service.saveHead(context.Background(), newRoot))

-	if service.HeadSlot() != 1 {
-		t.Error("Head did not change")
-	}
+	assert.Equal(t, types.Slot(1), service.HeadSlot(), "Head did not change")

 	cachedRoot, err := service.HeadRoot(context.Background())
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 	if !bytes.Equal(cachedRoot, newRoot[:]) {
 		t.Error("Head did not change")
 	}
-	if !reflect.DeepEqual(service.headBlock(), newHeadSignedBlock) {
-		t.Error("Head did not change")
-	}
-	if !reflect.DeepEqual(service.headState(ctx).CloneInnerState(), headState.CloneInnerState()) {
-		t.Error("Head did not change")
-	}
-	testutil.AssertLogsContain(t, hook, "Chain reorg occurred")
-}
-
-func TestUpdateRecentCanonicalBlocks_CanUpdateWithoutParent(t *testing.T) {
-	db, sc := testDB.SetupDB(t)
-	service := setupBeaconChain(t, db, sc)
-
-	r := [32]byte{'a'}
-	if err := service.updateRecentCanonicalBlocks(context.Background(), r); err != nil {
-		t.Fatal(err)
-	}
-	canonical, err := service.IsCanonical(context.Background(), r)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !canonical {
-		t.Error("Block should be canonical")
-	}
-}
-
-func TestUpdateRecentCanonicalBlocks_CanUpdateWithParent(t *testing.T) {
-	db, sc := testDB.SetupDB(t)
-	service := setupBeaconChain(t, db, sc)
-	oldHead := [32]byte{'a'}
-	if err := service.forkChoiceStore.ProcessBlock(context.Background(), 1, oldHead, [32]byte{'g'}, [32]byte{}, 0, 0); err != nil {
-		t.Fatal(err)
-	}
-	currentHead := [32]byte{'b'}
-	if err := service.forkChoiceStore.ProcessBlock(context.Background(), 3, currentHead, oldHead, [32]byte{}, 0, 0); err != nil {
-		t.Fatal(err)
-	}
-	forkedRoot := [32]byte{'c'}
-	if err := service.forkChoiceStore.ProcessBlock(context.Background(), 2, forkedRoot, oldHead, [32]byte{}, 0, 0); err != nil {
-		t.Fatal(err)
-	}
-
-	if err := service.updateRecentCanonicalBlocks(context.Background(), currentHead); err != nil {
-		t.Fatal(err)
-	}
-	canonical, err := service.IsCanonical(context.Background(), currentHead)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !canonical {
-		t.Error("Block should be canonical")
-	}
-	canonical, err = service.IsCanonical(context.Background(), oldHead)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !canonical {
-		t.Error("Block should be canonical")
-	}
-	canonical, err = service.IsCanonical(context.Background(), forkedRoot)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if canonical {
-		t.Error("Block should not be canonical")
-	}
+	assert.DeepEqual(t, newHeadSignedBlock, service.headBlock(), "Head did not change")
+	assert.DeepSSZEqual(t, headState.CloneInnerState(), service.headState(ctx).CloneInnerState(), "Head did not change")
+	require.LogsContain(t, hook, "Chain reorg occurred")
 }

 func TestCacheJustifiedStateBalances_CanCache(t *testing.T) {
-	db, sc := testDB.SetupDB(t)
-	service := setupBeaconChain(t, db, sc)
+	beaconDB := testDB.SetupDB(t)
+	service := setupBeaconChain(t, beaconDB)

 	state, _ := testutil.DeterministicGenesisState(t, 100)
 	r := [32]byte{'a'}
-	if err := service.beaconDB.SaveStateSummary(context.Background(), &pb.StateSummary{Root: r[:]}); err != nil {
-		t.Fatal(err)
-	}
-	if err := service.beaconDB.SaveState(context.Background(), state, r); err != nil {
-		t.Fatal(err)
-	}
-	if err := service.cacheJustifiedStateBalances(context.Background(), r); err != nil {
-		t.Fatal(err)
-	}
-	if !reflect.DeepEqual(state.Balances(), service.getJustifiedBalances()) {
-		t.Fatal("Incorrect justified balances")
-	}
+	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(context.Background(), &pb.StateSummary{Root: r[:]}))
+	require.NoError(t, service.cfg.BeaconDB.SaveState(context.Background(), state, r))
+	require.NoError(t, service.cacheJustifiedStateBalances(context.Background(), r))
+	require.DeepEqual(t, service.getJustifiedBalances(), state.Balances(), "Incorrect justified balances")
+}
+
+func TestUpdateHead_MissingJustifiedRoot(t *testing.T) {
+	beaconDB := testDB.SetupDB(t)
+	service := setupBeaconChain(t, beaconDB)
+
+	b := testutil.NewBeaconBlock()
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(context.Background(), b))
+	r, err := b.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	service.justifiedCheckpt = &ethpb.Checkpoint{Root: r[:]}
+	service.finalizedCheckpt = &ethpb.Checkpoint{}
+	service.bestJustifiedCheckpt = &ethpb.Checkpoint{}
+
+	require.NoError(t, service.updateHead(context.Background(), []uint64{}))
 }
--- a/beacon-chain/blockchain/info.go
+++ b/beacon-chain/blockchain/info.go
@@ -6,6 +6,7 @@ import (
 	"net/http"

 	"github.com/emicklei/dot"
+	"github.com/prysmaticlabs/prysm/shared/params"
 )

 const template = `<html>
@@ -33,37 +34,43 @@ const template = `<html>

 // TreeHandler is a handler to serve /tree page in metrics.
 func (s *Service) TreeHandler(w http.ResponseWriter, r *http.Request) {
-	if s.headState(r.Context()) == nil {
+	headState, err := s.HeadState(r.Context())
+	if err != nil {
+		log.WithError(err).Error("Could not get head state")
+		return
+	}
+	if headState == nil {
 		if _, err := w.Write([]byte("Unavailable during initial syncing")); err != nil {
 			log.WithError(err).Error("Failed to render p2p info page")
 		}
 	}

-	nodes := s.forkChoiceStore.Nodes()
+	nodes := s.cfg.ForkChoiceStore.Nodes()

 	graph := dot.NewGraph(dot.Directed)
 	graph.Attr("rankdir", "RL")
 	graph.Attr("labeljust", "l")

 	dotNodes := make([]*dot.Node, len(nodes))
-	avgBalance := uint64(averageBalance(s.headState(r.Context()).Balances()))
+	avgBalance := uint64(averageBalance(headState.Balances()))

 	for i := len(nodes) - 1; i >= 0; i-- {
 		// Construct label for each node.
-		slot := fmt.Sprintf("%d", nodes[i].Slot)
-		weight := fmt.Sprintf("%d", nodes[i].Weight/1e9) // Convert unit Gwei to unit ETH.
-		votes := fmt.Sprintf("%d", nodes[i].Weight/1e9/avgBalance)
+		slot := fmt.Sprintf("%d", nodes[i].Slot())
+		weight := fmt.Sprintf("%d", nodes[i].Weight()/1e9) // Convert unit Gwei to unit ETH.
+		votes := fmt.Sprintf("%d", nodes[i].Weight()/1e9/avgBalance)
 		index := fmt.Sprintf("%d", i)
-		g := nodes[i].Graffiti[:]
+		g := nodes[i].Graffiti()
 		graffiti := hex.EncodeToString(g[:8])
 		label := "slot: " + slot + "\n votes: " + votes + "\n weight: " + weight + "\n graffiti: " + graffiti
 		var dotN dot.Node
-		if nodes[i].Parent != ^uint64(0) {
+		if nodes[i].Parent() != ^uint64(0) {
 			dotN = graph.Node(index).Box().Attr("label", label)
 		}

-		if nodes[i].Slot == s.headSlot() &&
-			nodes[i].BestDescendant == ^uint64(0) {
+		if nodes[i].Slot() == s.HeadSlot() &&
+			nodes[i].BestDescendant() == ^uint64(0) &&
+			nodes[i].Parent() != ^uint64(0) {
 			dotN = dotN.Attr("color", "green")
 		}

@@ -71,8 +78,8 @@ func (s *Service) TreeHandler(w http.ResponseWriter, r *http.Request) {
 	}

 	for i := len(nodes) - 1; i >= 0; i-- {
-		if nodes[i].Parent != ^uint64(0) && nodes[i].Parent < uint64(len(dotNodes)) {
-			graph.Edge(*dotNodes[i], *dotNodes[nodes[i].Parent])
+		if nodes[i].Parent() != ^uint64(0) && nodes[i].Parent() < uint64(len(dotNodes)) {
+			graph.Edge(*dotNodes[i], *dotNodes[nodes[i].Parent()])
 		}
 	}

@@ -82,3 +89,11 @@ func (s *Service) TreeHandler(w http.ResponseWriter, r *http.Request) {
 		log.WithError(err).Error("Failed to render p2p info page")
 	}
 }
+
+func averageBalance(balances []uint64) float64 {
+	total := uint64(0)
+	for i := 0; i < len(balances); i++ {
+		total += balances[i]
+	}
+	return float64(total) / float64(len(balances)) / float64(params.BeaconConfig().GweiPerEth)
+}
--- a/beacon-chain/blockchain/info_test.go
+++ b/beacon-chain/blockchain/info_test.go
@@ -0,0 +1,48 @@
+package blockchain
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
+	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+)
+
+func TestService_TreeHandler(t *testing.T) {
+	req, err := http.NewRequest("GET", "/tree", nil)
+	require.NoError(t, err)
+
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+	headState, err := testutil.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, headState.SetBalances([]uint64{params.BeaconConfig().GweiPerEth}))
+	cfg := &Config{
+		BeaconDB: beaconDB,
+		ForkChoiceStore: protoarray.New(
+			0, // justifiedEpoch
+			0, // finalizedEpoch
+			[32]byte{'a'},
+		),
+		StateGen: stategen.New(beaconDB),
+	}
+	s, err := NewService(ctx, cfg)
+	require.NoError(t, err)
+	require.NoError(t, s.cfg.ForkChoiceStore.ProcessBlock(ctx, 0, [32]byte{'a'}, [32]byte{'g'}, [32]byte{'c'}, 0, 0))
+	require.NoError(t, s.cfg.ForkChoiceStore.ProcessBlock(ctx, 1, [32]byte{'b'}, [32]byte{'a'}, [32]byte{'c'}, 0, 0))
+	s.setHead([32]byte{'a'}, testutil.NewBeaconBlock(), headState)
+
+	rr := httptest.NewRecorder()
+	handler := http.HandlerFunc(s.TreeHandler)
+
+	handler.ServeHTTP(rr, req)
+
+	assert.Equal(t, http.StatusOK, rr.Code)
+}
--- a/beacon-chain/blockchain/init_sync_process_block.go
+++ b/beacon-chain/blockchain/init_sync_process_block.go
@@ -1,64 +1,9 @@
 package blockchain

 import (
-	"context"
-
-	"github.com/pkg/errors"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
 )

-func (s *Service) generateState(ctx context.Context, startRoot [32]byte, endRoot [32]byte) (*stateTrie.BeaconState, error) {
-	preState, err := s.beaconDB.State(ctx, startRoot)
-	if err != nil {
-		return nil, err
-	}
-	if preState == nil {
-		if !s.stateGen.HasState(ctx, startRoot) {
-			if err := s.beaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
-				return nil, errors.Wrap(err, "could not save initial sync blocks")
-			}
-			s.clearInitSyncBlocks()
-		}
-		preState, err = s.stateGen.StateByRoot(ctx, startRoot)
-		if err != nil {
-			return nil, err
-		}
-		if preState == nil {
-			return nil, errors.New("finalized state does not exist in db")
-		}
-	}
-
-	if err := s.beaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
-		return nil, err
-	}
-	var endBlock *ethpb.SignedBeaconBlock
-	if s.hasInitSyncBlock(endRoot) {
-		endBlock = s.getInitSyncBlock(endRoot)
-		s.clearInitSyncBlocks()
-	} else {
-		endBlock, err = s.beaconDB.Block(ctx, endRoot)
-		if err != nil {
-			return nil, err
-		}
-	}
-
-	if endBlock == nil {
-		return nil, errors.New("provided block root does not have block saved in the db")
-	}
-	log.Warnf("Generating missing state of slot %d and root %#x", endBlock.Block.Slot, endRoot)
-
-	blocks, err := s.stateGen.LoadBlocks(ctx, preState.Slot()+1, endBlock.Block.Slot, endRoot)
-	if err != nil {
-		return nil, errors.Wrap(err, "could not load the required blocks")
-	}
-	postState, err := s.stateGen.ReplayBlocks(ctx, preState, blocks, endBlock.Block.Slot)
-	if err != nil {
-		return nil, errors.Wrap(err, "could not replay the blocks to generate the resultant state")
-	}
-	return postState, nil
-}
-
 // This saves a beacon block to the initial sync blocks cache.
 func (s *Service) saveInitSyncBlock(r [32]byte, b *ethpb.SignedBeaconBlock) {
 	s.initSyncBlocksLock.Lock()
--- a/beacon-chain/blockchain/init_sync_process_block_test.go
+++ b/beacon-chain/blockchain/init_sync_process_block_test.go
@@ -1,97 +0,0 @@
-package blockchain
-
-import (
-	"context"
-	"testing"
-
-	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
-	"github.com/prysmaticlabs/go-ssz"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/state"
-	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateutil"
-	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
-	"github.com/prysmaticlabs/prysm/shared/params"
-	"github.com/prysmaticlabs/prysm/shared/testutil"
-	"gopkg.in/d4l3k/messagediff.v1"
-)
-
-func TestGenerateState_CorrectlyGenerated(t *testing.T) {
-	db, sc := testDB.SetupDB(t)
-	cfg := &Config{BeaconDB: db, StateGen: stategen.New(db, sc)}
-	service, err := NewService(context.Background(), cfg)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	beaconState, privs := testutil.DeterministicGenesisState(t, 32)
-	genesisBlock := testutil.NewBeaconBlock()
-	bodyRoot, err := stateutil.BlockRoot(genesisBlock.Block)
-	if err != nil {
-		t.Fatal(err)
-	}
-	err = beaconState.SetLatestBlockHeader(&ethpb.BeaconBlockHeader{
-		Slot:       genesisBlock.Block.Slot,
-		ParentRoot: genesisBlock.Block.ParentRoot,
-		StateRoot:  params.BeaconConfig().ZeroHash[:],
-		BodyRoot:   bodyRoot[:],
-	})
-	if err != nil {
-		t.Fatal(err)
-	}
-	if err := beaconState.SetSlashings(make([]uint64, params.BeaconConfig().EpochsPerSlashingsVector)); err != nil {
-		t.Fatal(err)
-	}
-	cp := beaconState.CurrentJustifiedCheckpoint()
-	mockRoot := [32]byte{}
-	copy(mockRoot[:], "hello-world")
-	cp.Root = mockRoot[:]
-	if err := beaconState.SetCurrentJustifiedCheckpoint(cp); err != nil {
-		t.Fatal(err)
-	}
-	if err := beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}); err != nil {
-		t.Fatal(err)
-	}
-	err = db.SaveBlock(context.Background(), genesisBlock)
-	if err != nil {
-		t.Fatal(err)
-	}
-	genRoot, err := stateutil.BlockRoot(genesisBlock.Block)
-	if err != nil {
-		t.Fatal(err)
-	}
-	err = db.SaveState(context.Background(), beaconState, genRoot)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	lastBlock := &ethpb.SignedBeaconBlock{}
-	for i := uint64(1); i < 10; i++ {
-		block, err := testutil.GenerateFullBlock(beaconState, privs, testutil.DefaultBlockGenConfig(), i)
-		if err != nil {
-			t.Fatal(err)
-		}
-		beaconState, err = state.ExecuteStateTransition(context.Background(), beaconState, block)
-		if err != nil {
-			t.Fatal(err)
-		}
-		err = db.SaveBlock(context.Background(), block)
-		if err != nil {
-			t.Fatal(err)
-		}
-		lastBlock = block
-	}
-	root, err := stateutil.BlockRoot(lastBlock.Block)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	newState, err := service.generateState(context.Background(), genRoot, root)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !ssz.DeepEqual(newState.InnerStateUnsafe(), beaconState.InnerStateUnsafe()) {
-		diff, _ := messagediff.PrettyDiff(newState.InnerStateUnsafe(), beaconState.InnerStateUnsafe())
-		t.Errorf("Generated state is different from what is expected: %s", diff)
-	}
-}
--- a/beacon-chain/blockchain/init_test.go
+++ b/beacon-chain/blockchain/init_test.go
@@ -0,0 +1,12 @@
+package blockchain
+
+import (
+	"github.com/prysmaticlabs/prysm/shared/params"
+)
+
+func init() {
+	// Override network name so that hardcoded genesis files are not loaded.
+	cfg := params.BeaconConfig()
+	cfg.ConfigName = "test"
+	params.OverrideBeaconConfig(cfg)
+}
--- a/beacon-chain/blockchain/log.go
+++ b/beacon-chain/blockchain/log.go
@@ -3,11 +3,12 @@ package blockchain
 import (
 	"encoding/hex"
 	"fmt"
+	"time"

 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/timeutils"
 	"github.com/sirupsen/logrus"
 )

@@ -15,48 +16,42 @@ var log = logrus.WithField("prefix", "blockchain")

 // logs state transition related data every slot.
 func logStateTransitionData(b *ethpb.BeaconBlock) {
-	log.WithFields(logrus.Fields{
-		"attestations":      len(b.Body.Attestations),
-		"deposits":          len(b.Body.Deposits),
-		"attesterSlashings": len(b.Body.AttesterSlashings),
-		"proposerSlashings": len(b.Body.ProposerSlashings),
-		"voluntaryExits":    len(b.Body.VoluntaryExits),
-	}).Info("Finished applying state transition")
+	log := log.WithField("slot", b.Slot)
+	if len(b.Body.Attestations) > 0 {
+		log = log.WithField("attestations", len(b.Body.Attestations))
+	}
+	if len(b.Body.Deposits) > 0 {
+		log = log.WithField("deposits", len(b.Body.Deposits))
+	}
+	if len(b.Body.AttesterSlashings) > 0 {
+		log = log.WithField("attesterSlashings", len(b.Body.AttesterSlashings))
+	}
+	if len(b.Body.ProposerSlashings) > 0 {
+		log = log.WithField("proposerSlashings", len(b.Body.ProposerSlashings))
+	}
+	if len(b.Body.VoluntaryExits) > 0 {
+		log = log.WithField("voluntaryExits", len(b.Body.VoluntaryExits))
+	}
+	log.Info("Finished applying state transition")
 }

-func logBlockSyncStatus(block *ethpb.BeaconBlock, blockRoot [32]byte, finalized *ethpb.Checkpoint) {
+func logBlockSyncStatus(block *ethpb.BeaconBlock, blockRoot [32]byte, finalized *ethpb.Checkpoint, receivedTime time.Time, genesisTime uint64) error {
+	startTime, err := helpers.SlotToTime(genesisTime, block.Slot)
+	if err != nil {
+		return err
+	}
 	log.WithFields(logrus.Fields{
 		"slot":           block.Slot,
+		"slotInEpoch":    block.Slot % params.BeaconConfig().SlotsPerEpoch,
 		"block":          fmt.Sprintf("0x%s...", hex.EncodeToString(blockRoot[:])[:8]),
 		"epoch":          helpers.SlotToEpoch(block.Slot),
 		"finalizedEpoch": finalized.Epoch,
-		"finalizedRoot":  fmt.Sprintf("0x%s...", hex.EncodeToString(finalized.Root[:])[:8]),
+		"finalizedRoot":  fmt.Sprintf("0x%s...", hex.EncodeToString(finalized.Root)[:8]),
 	}).Info("Synced new block")
-}
-
-func logEpochData(beaconState *stateTrie.BeaconState) {
 	log.WithFields(logrus.Fields{
-		"epoch":                  helpers.CurrentEpoch(beaconState),
-		"finalizedEpoch":         beaconState.FinalizedCheckpointEpoch(),
-		"justifiedEpoch":         beaconState.CurrentJustifiedCheckpoint().Epoch,
-		"previousJustifiedEpoch": beaconState.PreviousJustifiedCheckpoint().Epoch,
-	}).Info("Starting next epoch")
-	activeVals, err := helpers.ActiveValidatorIndices(beaconState, helpers.CurrentEpoch(beaconState))
-	if err != nil {
-		log.WithError(err).Error("Could not get active validator indices")
-		return
-	}
-	log.WithFields(logrus.Fields{
-		"totalValidators":  len(beaconState.Validators()),
-		"activeValidators": len(activeVals),
-		"averageBalance":   fmt.Sprintf("%.5f ETH", averageBalance(beaconState.Balances())),
-	}).Info("Validator registry information")
-}
-
-func averageBalance(balances []uint64) float64 {
-	total := uint64(0)
-	for i := 0; i < len(balances); i++ {
-		total += balances[i]
-	}
-	return float64(total) / float64(len(balances)) / float64(params.BeaconConfig().GweiPerEth)
+		"slot":                      block.Slot,
+		"sinceSlotStartTime":        timeutils.Now().Sub(startTime),
+		"chainServiceProcessedTime": timeutils.Now().Sub(receivedTime),
+	}).Debug("Sync new block times")
+	return nil
 }
--- a/beacon-chain/blockchain/log_test.go
+++ b/beacon-chain/blockchain/log_test.go
@@ -0,0 +1,63 @@
+package blockchain
+
+import (
+	"testing"
+
+	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+	logTest "github.com/sirupsen/logrus/hooks/test"
+)
+
+func Test_logStateTransitionData(t *testing.T) {
+	tests := []struct {
+		name string
+		b    *ethpb.BeaconBlock
+		want string
+	}{
+		{name: "empty block body",
+			b:    &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{}},
+			want: "\"Finished applying state transition\" prefix=blockchain slot=0",
+		},
+		{name: "has attestation",
+			b:    &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{Attestations: []*ethpb.Attestation{{}}}},
+			want: "\"Finished applying state transition\" attestations=1 prefix=blockchain slot=0",
+		},
+		{name: "has deposit",
+			b: &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{
+				Attestations: []*ethpb.Attestation{{}},
+				Deposits:     []*ethpb.Deposit{{}}}},
+			want: "\"Finished applying state transition\" attestations=1 deposits=1 prefix=blockchain slot=0",
+		},
+		{name: "has attester slashing",
+			b: &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{
+				AttesterSlashings: []*ethpb.AttesterSlashing{{}}}},
+			want: "\"Finished applying state transition\" attesterSlashings=1 prefix=blockchain slot=0",
+		},
+		{name: "has proposer slashing",
+			b: &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{
+				ProposerSlashings: []*ethpb.ProposerSlashing{{}}}},
+			want: "\"Finished applying state transition\" prefix=blockchain proposerSlashings=1 slot=0",
+		},
+		{name: "has exit",
+			b: &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{
+				VoluntaryExits: []*ethpb.SignedVoluntaryExit{{}}}},
+			want: "\"Finished applying state transition\" prefix=blockchain slot=0 voluntaryExits=1",
+		},
+		{name: "has everything",
+			b: &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{
+				Attestations:      []*ethpb.Attestation{{}},
+				Deposits:          []*ethpb.Deposit{{}},
+				AttesterSlashings: []*ethpb.AttesterSlashing{{}},
+				ProposerSlashings: []*ethpb.ProposerSlashing{{}},
+				VoluntaryExits:    []*ethpb.SignedVoluntaryExit{{}}}},
+			want: "\"Finished applying state transition\" attestations=1 attesterSlashings=1 deposits=1 prefix=blockchain proposerSlashings=1 slot=0 voluntaryExits=1",
+		},
+	}
+	for _, tt := range tests {
+		hook := logTest.NewGlobal()
+		t.Run(tt.name, func(t *testing.T) {
+			logStateTransitionData(tt.b)
+			require.LogsContain(t, hook, tt.want)
+		})
+	}
+}
--- a/beacon-chain/blockchain/metrics.go
+++ b/beacon-chain/blockchain/metrics.go
@@ -1,17 +1,16 @@
 package blockchain

 import (
-	"time"
+	"context"

 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
+	types "github.com/prysmaticlabs/eth2-types"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/epoch/precompute"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
-	"github.com/prysmaticlabs/prysm/shared/roughtime"
 )

 var (
@@ -76,25 +75,30 @@ var (
 		Name: "current_eth1_data_deposit_count",
 		Help: "The current eth1 deposit count in the last processed state eth1data field.",
 	})
-	totalEligibleBalances = promauto.NewGauge(prometheus.GaugeOpts{
-		Name: "total_eligible_balances",
-		Help: "The total amount of ether, in gwei, that is eligible for voting of previous epoch",
+	stateTrieReferences = promauto.NewGaugeVec(prometheus.GaugeOpts{
+		Name: "field_references",
+		Help: "The number of states a particular field is shared with.",
+	}, []string{"state"})
+	prevEpochActiveBalances = promauto.NewGauge(prometheus.GaugeOpts{
+		Name: "beacon_prev_epoch_active_gwei",
+		Help: "The total amount of ether, in gwei, that was active for voting of previous epoch",
 	})
-	totalVotedTargetBalances = promauto.NewGauge(prometheus.GaugeOpts{
-		Name: "total_voted_target_balances",
+	prevEpochSourceBalances = promauto.NewGauge(prometheus.GaugeOpts{
+		Name: "beacon_prev_epoch_source_gwei",
+		Help: "The total amount of ether, in gwei, that has been used in voting attestation source of previous epoch",
+	})
+	prevEpochTargetBalances = promauto.NewGauge(prometheus.GaugeOpts{
+		Name: "beacon_prev_epoch_target_gwei",
 		Help: "The total amount of ether, in gwei, that has been used in voting attestation target of previous epoch",
 	})
+	prevEpochHeadBalances = promauto.NewGauge(prometheus.GaugeOpts{
+		Name: "beacon_prev_epoch_head_gwei",
+		Help: "The total amount of ether, in gwei, that has been used in voting attestation head of previous epoch",
+	})
 	reorgCount = promauto.NewCounter(prometheus.CounterOpts{
 		Name: "beacon_reorg_total",
 		Help: "Count the number of times beacon chain has a reorg",
 	})
-	sentBlockPropagationHistogram = promauto.NewHistogram(
-		prometheus.HistogramOpts{
-			Name:    "block_sent_latency_milliseconds",
-			Help:    "Captures blocks broadcast time. Blocks sent in milliseconds distribution",
-			Buckets: []float64{1000, 2000, 3000, 4000, 5000, 6000},
-		},
-	)
 	attestationInclusionDelay = promauto.NewHistogram(
 		prometheus.HistogramOpts{
 			Name:    "attestation_inclusion_delay_slots",
@@ -105,7 +109,7 @@ var (
 )

 // reportSlotMetrics reports slot related metrics.
-func reportSlotMetrics(stateSlot uint64, headSlot uint64, clockSlot uint64, finalizedCheckpoint *ethpb.Checkpoint) {
+func reportSlotMetrics(stateSlot, headSlot, clockSlot types.Slot, finalizedCheckpoint *ethpb.Checkpoint) {
 	clockTimeSlot.Set(float64(clockSlot))
 	beaconSlot.Set(float64(stateSlot))
 	beaconHeadSlot.Set(float64(headSlot))
@@ -116,8 +120,8 @@ func reportSlotMetrics(stateSlot uint64, headSlot uint64, clockSlot uint64, fina
 }

 // reportEpochMetrics reports epoch related metrics.
-func reportEpochMetrics(state *stateTrie.BeaconState) {
-	currentEpoch := state.Slot() / params.BeaconConfig().SlotsPerEpoch
+func reportEpochMetrics(ctx context.Context, postState, headState iface.BeaconState) error {
+	currentEpoch := types.Epoch(postState.Slot() / params.BeaconConfig().SlotsPerEpoch)

 	// Validator instances
 	pendingInstances := 0
@@ -135,8 +139,8 @@ func reportEpochMetrics(state *stateTrie.BeaconState) {
 	slashingBalance := uint64(0)
 	slashingEffectiveBalance := uint64(0)

-	for i, validator := range state.Validators() {
-		bal, err := state.BalanceAtIndex(uint64(i))
+	for i, validator := range postState.Validators() {
+		bal, err := postState.BalanceAtIndex(types.ValidatorIndex(i))
 		if err != nil {
 			log.Errorf("Could not load validator balance: %v", err)
 			continue
@@ -170,6 +174,10 @@ func reportEpochMetrics(state *stateTrie.BeaconState) {
 		activeBalance += bal
 		activeEffectiveBalance += validator.EffectiveBalance
 	}
+	activeInstances += exitingInstances + slashingInstances
+	activeBalance += exitingBalance + slashingBalance
+	activeEffectiveBalance += exitingEffectiveBalance + slashingEffectiveBalance
+
 	validatorsCount.WithLabelValues("Pending").Set(float64(pendingInstances))
 	validatorsCount.WithLabelValues("Active").Set(float64(activeInstances))
 	validatorsCount.WithLabelValues("Exiting").Set(float64(exitingInstances))
@@ -185,33 +193,36 @@ func reportEpochMetrics(state *stateTrie.BeaconState) {
 	validatorsEffectiveBalance.WithLabelValues("Slashing").Set(float64(slashingEffectiveBalance))

 	// Last justified slot
-	beaconCurrentJustifiedEpoch.Set(float64(state.CurrentJustifiedCheckpoint().Epoch))
-	beaconCurrentJustifiedRoot.Set(float64(bytesutil.ToLowInt64(state.CurrentJustifiedCheckpoint().Root)))
+	beaconCurrentJustifiedEpoch.Set(float64(postState.CurrentJustifiedCheckpoint().Epoch))
+	beaconCurrentJustifiedRoot.Set(float64(bytesutil.ToLowInt64(postState.CurrentJustifiedCheckpoint().Root)))

 	// Last previous justified slot
-	beaconPrevJustifiedEpoch.Set(float64(state.PreviousJustifiedCheckpoint().Epoch))
-	beaconPrevJustifiedRoot.Set(float64(bytesutil.ToLowInt64(state.PreviousJustifiedCheckpoint().Root)))
+	beaconPrevJustifiedEpoch.Set(float64(postState.PreviousJustifiedCheckpoint().Epoch))
+	beaconPrevJustifiedRoot.Set(float64(bytesutil.ToLowInt64(postState.PreviousJustifiedCheckpoint().Root)))

 	// Last finalized slot
-	beaconFinalizedEpoch.Set(float64(state.FinalizedCheckpointEpoch()))
-	beaconFinalizedRoot.Set(float64(bytesutil.ToLowInt64(state.FinalizedCheckpoint().Root)))
+	beaconFinalizedEpoch.Set(float64(postState.FinalizedCheckpointEpoch()))
+	beaconFinalizedRoot.Set(float64(bytesutil.ToLowInt64(postState.FinalizedCheckpoint().Root)))
+	currentEth1DataDepositCount.Set(float64(postState.Eth1Data().DepositCount))

-	currentEth1DataDepositCount.Set(float64(state.Eth1Data().DepositCount))
-
-	if precompute.Balances != nil {
-		totalEligibleBalances.Set(float64(precompute.Balances.ActivePrevEpoch))
-		totalVotedTargetBalances.Set(float64(precompute.Balances.PrevEpochTargetAttested))
-	}
-}
-
-// This captures metrics for block sent time by subtracts slot start time.
-func captureSentTimeMetric(genesisTime uint64, currentSlot uint64) error {
-	startTime, err := helpers.SlotToTime(genesisTime, currentSlot)
+	// Validator participation should be viewed on the canonical chain.
+	v, b, err := precompute.New(ctx, headState)
 	if err != nil {
 		return err
 	}
-	diffMs := roughtime.Now().Sub(startTime) / time.Millisecond
-	sentBlockPropagationHistogram.Observe(float64(diffMs))
+	_, b, err = precompute.ProcessAttestations(ctx, headState, v, b)
+	if err != nil {
+		return err
+	}
+	prevEpochActiveBalances.Set(float64(b.ActivePrevEpoch))
+	prevEpochSourceBalances.Set(float64(b.PrevEpochAttested))
+	prevEpochTargetBalances.Set(float64(b.PrevEpochTargetAttested))
+	prevEpochHeadBalances.Set(float64(b.PrevEpochHeadAttested))
+
+	refMap := postState.FieldReferencesCount()
+	for name, val := range refMap {
+		stateTrieReferences.WithLabelValues(name).Set(float64(val))
+	}

 	return nil
 }
--- a/beacon-chain/blockchain/metrics_test.go
+++ b/beacon-chain/blockchain/metrics_test.go
@@ -0,0 +1,42 @@
+package blockchain
+
+import (
+	"context"
+	"testing"
+
+	eth "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
+	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+)
+
+func TestReportEpochMetrics_BadHeadState(t *testing.T) {
+	s, err := testutil.NewBeaconState()
+	require.NoError(t, err)
+	h, err := testutil.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, h.SetValidators(nil))
+	err = reportEpochMetrics(context.Background(), s, h)
+	require.ErrorContains(t, "failed to initialize precompute: nil validators in state", err)
+}
+
+func TestReportEpochMetrics_BadAttestation(t *testing.T) {
+	s, err := testutil.NewBeaconState()
+	require.NoError(t, err)
+	h, err := testutil.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, h.AppendCurrentEpochAttestations(&pb.PendingAttestation{InclusionDelay: 0}))
+	err = reportEpochMetrics(context.Background(), s, h)
+	require.ErrorContains(t, "attestation with inclusion delay of 0", err)
+}
+
+func TestReportEpochMetrics_SlashedValidatorOutOfBound(t *testing.T) {
+	h, _ := testutil.DeterministicGenesisState(t, 1)
+	v, err := h.ValidatorAtIndex(0)
+	require.NoError(t, err)
+	v.Slashed = true
+	require.NoError(t, h.UpdateValidatorAtIndex(0, v))
+	require.NoError(t, h.AppendCurrentEpochAttestations(&pb.PendingAttestation{InclusionDelay: 1, Data: testutil.HydrateAttestationData(&eth.AttestationData{})}))
+	err = reportEpochMetrics(context.Background(), h, h)
+	require.ErrorContains(t, "slot 0 out of bounds", err)
+}
--- a/beacon-chain/blockchain/process_attestation.go
+++ b/beacon-chain/blockchain/process_attestation.go
@@ -2,145 +2,102 @@ package blockchain

 import (
 	"context"
-	"fmt"

 	"github.com/pkg/errors"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	"github.com/prysmaticlabs/prysm/beacon-chain/flags"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateV0"
+	"github.com/prysmaticlabs/prysm/shared/attestationutil"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
-	"github.com/prysmaticlabs/prysm/shared/roughtime"
+	"github.com/prysmaticlabs/prysm/shared/timeutils"
 	"go.opencensus.io/trace"
 )

-// ErrTargetRootNotInDB returns when the target block root of an attestation cannot be found in the
-// beacon database.
-var ErrTargetRootNotInDB = errors.New("target root does not exist in db")
-
 // onAttestation is called whenever an attestation is received, verifies the attestation is valid and saves
 // it to the DB. As a stateless function, this does not hold nor delay attestation based on the spec descriptions.
-// The delay is handled by the caller in `processAttestation`.
+// The delay is handled by the caller in `processAttestations`.
 //
 // Spec pseudocode definition:
-//   def on_attestation(store: Service, attestation: Attestation) -> None:
+//   def on_attestation(store: Store, attestation: Attestation) -> None:
 //    """
 //    Run ``on_attestation`` upon receiving a new ``attestation`` from either within a block or directly on the wire.
 //
 //    An ``attestation`` that is asserted as invalid may be valid at a later time,
 //    consider scheduling it for later processing in such case.
 //    """
-//    target = attestation.data.target
+//    validate_on_attestation(store, attestation)
+//    store_target_checkpoint_state(store, attestation.data.target)
 //
-//    # Attestations must be from the current or previous epoch
-//    current_epoch = compute_epoch_at_slot(get_current_slot(store))
-//    # Use GENESIS_EPOCH for previous when genesis to avoid underflow
-//    previous_epoch = current_epoch - 1 if current_epoch > GENESIS_EPOCH else GENESIS_EPOCH
-//    # If attestation target is from a future epoch, delay consideration until the epoch arrives
-//    assert target.epoch in [current_epoch, previous_epoch]
-//    assert target.epoch == compute_epoch_at_slot(attestation.data.slot)
-//
-//    # Attestations target be for a known block. If target block is unknown, delay consideration until the block is found
-//    assert target.root in store.blocks
-//
-//    # Attestations must be for a known block. If block is unknown, delay consideration until the block is found
-//    assert attestation.data.beacon_block_root in store.blocks
-//    # Attestations must not be for blocks in the future. If not, the attestation should not be considered
-//    assert store.blocks[attestation.data.beacon_block_root].slot <= attestation.data.slot
-//
-//    # Service target checkpoint state if not yet seen
-//    if target not in store.checkpoint_states:
-//        process_slots(base_state, compute_start_slot_at_epoch(target.epoch))
-//        store.checkpoint_states[target] = base_state
-//    target_state = store.checkpoint_states[target]
-//
-//    # Attestations can only affect the fork choice of subsequent slots.
-//    # Delay consideration in the fork choice until their slot is in the past.
-//    assert store.time >= (attestation.data.slot + 1) * SECONDS_PER_SLOT
-//
-//    # Get state at the `target` to validate attestation and calculate the committees
+//    # Get state at the `target` to fully validate attestation
+//    target_state = store.checkpoint_states[attestation.data.target]
 //    indexed_attestation = get_indexed_attestation(target_state, attestation)
 //    assert is_valid_indexed_attestation(target_state, indexed_attestation)
 //
-//    # Update latest messages
-//    for i in indexed_attestation.attesting_indices:
-//        if i not in store.latest_messages or target.epoch > store.latest_messages[i].epoch:
-//            store.latest_messages[i] = LatestMessage(epoch=target.epoch, root=attestation.data.beacon_block_root)
-// TODO(#6072): This code path is highly untested. Requires comprehensive tests and simpler refactoring.
-func (s *Service) onAttestation(ctx context.Context, a *ethpb.Attestation) ([]uint64, error) {
-	ctx, span := trace.StartSpan(ctx, "blockchain.onAttestation")
+//    # Update latest messages for attesting indices
+//    update_latest_messages(store, indexed_attestation.attesting_indices, attestation)
+func (s *Service) onAttestation(ctx context.Context, a *ethpb.Attestation) error {
+	ctx, span := trace.StartSpan(ctx, "blockChain.onAttestation")
 	defer span.End()

-	if a == nil {
-		return nil, errors.New("nil attestation")
+	if err := helpers.ValidateNilAttestation(a); err != nil {
+		return err
 	}
-	if a.Data == nil {
-		return nil, errors.New("nil attestation.Data field")
-	}
-	if a.Data.Target == nil {
-		return nil, errors.New("nil attestation.Data.Target field")
+	if err := helpers.ValidateSlotTargetEpoch(a.Data); err != nil {
+		return err
 	}
+	tgt := stateV0.CopyCheckpoint(a.Data.Target)

-	tgt := stateTrie.CopyCheckpoint(a.Data.Target)
-
-	if helpers.SlotToEpoch(a.Data.Slot) != a.Data.Target.Epoch {
-		return nil, fmt.Errorf("data slot is not in the same epoch as target %d != %d", helpers.SlotToEpoch(a.Data.Slot), a.Data.Target.Epoch)
-	}
-
-	// Verify beacon node has seen the target block before.
-	if !s.hasBlock(ctx, bytesutil.ToBytes32(tgt.Root)) {
-		return nil, ErrTargetRootNotInDB
-	}
+	// Note that target root check is ignored here because it was performed in sync's validation pipeline:
+	// validate_aggregate_proof.go and validate_beacon_attestation.go
+	// If missing target root were to fail in this method, it would have just failed in `getAttPreState`.

 	// Retrieve attestation's data beacon block pre state. Advance pre state to latest epoch if necessary and
 	// save it to the cache.
 	baseState, err := s.getAttPreState(ctx, tgt)
 	if err != nil {
-		return nil, err
+		return err
 	}

 	genesisTime := baseState.GenesisTime()

 	// Verify attestation target is from current epoch or previous epoch.
-	if err := s.verifyAttTargetEpoch(ctx, genesisTime, uint64(roughtime.Now().Unix()), tgt); err != nil {
-		return nil, err
+	if err := s.verifyAttTargetEpoch(ctx, genesisTime, uint64(timeutils.Now().Unix()), tgt); err != nil {
+		return err
 	}

 	// Verify attestation beacon block is known and not from the future.
 	if err := s.verifyBeaconBlock(ctx, a.Data); err != nil {
-		return nil, errors.Wrap(err, "could not verify attestation beacon block")
+		return errors.Wrap(err, "could not verify attestation beacon block")
 	}

-	// Verify LMG GHOST and FFG votes are consistent with each other.
-	if err := s.verifyLMDFFGConsistent(ctx, a.Data.Target.Epoch, a.Data.Target.Root, a.Data.BeaconBlockRoot); err != nil {
-		return nil, errors.Wrap(err, "could not verify attestation beacon block")
-	}
+	// Note that LMG GHOST and FFG consistency check is ignored because it was performed in sync's validation pipeline:
+	// validate_aggregate_proof.go and validate_beacon_attestation.go

 	// Verify attestations can only affect the fork choice of subsequent slots.
 	if err := helpers.VerifySlotTime(genesisTime, a.Data.Slot+1, params.BeaconNetworkConfig().MaximumGossipClockDisparity); err != nil {
-		return nil, err
+		return err
 	}

-	// Use the target state to validate attestation and calculate the committees.
-	indexedAtt, err := s.verifyAttestation(ctx, baseState, a)
+	// Use the target state to verify attesting indices are valid.
+	committee, err := helpers.BeaconCommitteeFromState(baseState, a.Data.Slot, a.Data.CommitteeIndex)
 	if err != nil {
-		return nil, err
+		return err
+	}
+	indexedAtt, err := attestationutil.ConvertToIndexed(ctx, a, committee)
+	if err != nil {
+		return err
+	}
+	if err := attestationutil.IsValidAttestationIndices(ctx, indexedAtt); err != nil {
+		return err
 	}

-	// Only save attestation in DB for archival node.
-	if flags.Get().EnableArchive {
-		if err := s.beaconDB.SaveAttestation(ctx, a); err != nil {
-			return nil, err
-		}
-	}
-
-	if indexedAtt.AttestingIndices == nil {
-		return nil, errors.New("nil attesting indices")
-	}
+	// Note that signature verification is ignored here because it was performed in sync's validation pipeline:
+	// validate_aggregate_proof.go and validate_beacon_attestation.go
+	// We assume trusted attestation in this function has verified signature.

 	// Update forkchoice store with the new attestation for updating weight.
-	s.forkChoiceStore.ProcessAttestation(ctx, indexedAtt.AttestingIndices, bytesutil.ToBytes32(a.Data.BeaconBlockRoot), a.Data.Target.Epoch)
+	s.cfg.ForkChoiceStore.ProcessAttestation(ctx, indexedAtt.AttestingIndices, bytesutil.ToBytes32(a.Data.BeaconBlockRoot), a.Data.Target.Epoch)

-	return indexedAtt.AttestingIndices, nil
+	return nil
 }
--- a/beacon-chain/blockchain/process_attestation_helpers.go
+++ b/beacon-chain/blockchain/process_attestation_helpers.go
@@ -1,27 +1,31 @@
 package blockchain

 import (
-	"bytes"
 	"context"
 	"fmt"
+	"strconv"

 	"github.com/pkg/errors"
+	types "github.com/prysmaticlabs/eth2-types"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
-	"github.com/prysmaticlabs/prysm/beacon-chain/cache"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/state"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/shared/attestationutil"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/featureconfig"
+	"github.com/prysmaticlabs/prysm/shared/mputil"
 	"github.com/prysmaticlabs/prysm/shared/params"
 )

 // getAttPreState retrieves the att pre state by either from the cache or the DB.
-func (s *Service) getAttPreState(ctx context.Context, c *ethpb.Checkpoint) (*stateTrie.BeaconState, error) {
-	s.checkpointStateLock.Lock()
-	defer s.checkpointStateLock.Unlock()
-	cachedState, err := s.checkpointState.StateByCheckpoint(c)
+func (s *Service) getAttPreState(ctx context.Context, c *ethpb.Checkpoint) (iface.BeaconState, error) {
+	// Use a multilock to allow scoped holding of a mutex by a checkpoint root + epoch
+	// allowing us to behave smarter in terms of how this function is used concurrently.
+	epochKey := strconv.FormatUint(uint64(c.Epoch), 10 /* base 10 */)
+	lock := mputil.NewMultilock(string(c.Root) + epochKey)
+	lock.Lock()
+	defer lock.Unlock()
+	cachedState, err := s.checkpointStateCache.StateByCheckpoint(c)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not get cached checkpoint state")
 	}
@@ -29,42 +33,53 @@ func (s *Service) getAttPreState(ctx context.Context, c *ethpb.Checkpoint) (*sta
 		return cachedState, nil
 	}

-	if !s.stateGen.HasState(ctx, bytesutil.ToBytes32(c.Root)) {
-		if err := s.beaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
-			return nil, errors.Wrap(err, "could not save initial sync blocks")
-		}
-		s.clearInitSyncBlocks()
-	}
-
-	baseState, err := s.stateGen.StateByRoot(ctx, bytesutil.ToBytes32(c.Root))
+	baseState, err := s.cfg.StateGen.StateByRoot(ctx, bytesutil.ToBytes32(c.Root))
 	if err != nil {
-		return nil, errors.Wrapf(err, "could not get pre state for slot %d", helpers.StartSlot(c.Epoch))
+		return nil, errors.Wrapf(err, "could not get pre state for epoch %d", c.Epoch)
 	}

-	if helpers.StartSlot(c.Epoch) > baseState.Slot() {
-		baseState = baseState.Copy()
-		baseState, err = state.ProcessSlots(ctx, baseState, helpers.StartSlot(c.Epoch))
-		if err != nil {
-			return nil, errors.Wrapf(err, "could not process slots up to %d", helpers.StartSlot(c.Epoch))
+	epochStartSlot, err := helpers.StartSlot(c.Epoch)
+	if err != nil {
+		return nil, err
+	}
+	if epochStartSlot > baseState.Slot() {
+		if featureconfig.Get().EnableNextSlotStateCache {
+			baseState, err = state.ProcessSlotsUsingNextSlotCache(ctx, baseState, c.Root, epochStartSlot)
+			if err != nil {
+				return nil, errors.Wrapf(err, "could not process slots up to epoch %d", c.Epoch)
+			}
+		} else {
+			baseState, err = state.ProcessSlots(ctx, baseState, epochStartSlot)
+			if err != nil {
+				return nil, errors.Wrapf(err, "could not process slots up to epoch %d", c.Epoch)
+			}
+		}
+		if err := s.checkpointStateCache.AddCheckpointState(c, baseState); err != nil {
+			return nil, errors.Wrap(err, "could not saved checkpoint state to cache")
+		}
+		return baseState, nil
+	}
+
+	// To avoid sharing the same state across checkpoint state cache and hot state cache,
+	// we don't add the state to check point cache.
+	has, err := s.cfg.StateGen.HasStateInCache(ctx, bytesutil.ToBytes32(c.Root))
+	if err != nil {
+		return nil, err
+	}
+	if !has {
+		if err := s.checkpointStateCache.AddCheckpointState(c, baseState); err != nil {
+			return nil, errors.Wrap(err, "could not saved checkpoint state to cache")
 		}
 	}
-
-	if err := s.checkpointState.AddCheckpointState(&cache.CheckpointState{
-		Checkpoint: c,
-		State:      baseState,
-	}); err != nil {
-		return nil, errors.Wrap(err, "could not saved checkpoint state to cache")
-	}
-
 	return baseState, nil

 }

 // verifyAttTargetEpoch validates attestation is from the current or previous epoch.
-func (s *Service) verifyAttTargetEpoch(ctx context.Context, genesisTime uint64, nowTime uint64, c *ethpb.Checkpoint) error {
-	currentSlot := (nowTime - genesisTime) / params.BeaconConfig().SecondsPerSlot
+func (s *Service) verifyAttTargetEpoch(_ context.Context, genesisTime, nowTime uint64, c *ethpb.Checkpoint) error {
+	currentSlot := types.Slot((nowTime - genesisTime) / params.BeaconConfig().SecondsPerSlot)
 	currentEpoch := helpers.SlotToEpoch(currentSlot)
-	var prevEpoch uint64
+	var prevEpoch types.Epoch
 	// Prevents previous epoch under flow
 	if currentEpoch > 1 {
 		prevEpoch = currentEpoch - 1
@@ -77,42 +92,21 @@ func (s *Service) verifyAttTargetEpoch(ctx context.Context, genesisTime uint64,

 // verifyBeaconBlock verifies beacon head block is known and not from the future.
 func (s *Service) verifyBeaconBlock(ctx context.Context, data *ethpb.AttestationData) error {
-	b, err := s.beaconDB.Block(ctx, bytesutil.ToBytes32(data.BeaconBlockRoot))
+	r := bytesutil.ToBytes32(data.BeaconBlockRoot)
+	b, err := s.cfg.BeaconDB.Block(ctx, r)
 	if err != nil {
 		return err
 	}
-	if b == nil || b.Block == nil {
-		return fmt.Errorf("beacon block %#x does not exist", bytesutil.Trunc(data.BeaconBlockRoot))
+	// If the block does not exist in db, check again if block exists in initial sync block cache.
+	// This could happen as the node first syncs to head.
+	if b == nil && s.hasInitSyncBlock(r) {
+		b = s.getInitSyncBlock(r)
+	}
+	if err := helpers.VerifyNilBeaconBlock(b); err != nil {
+		return err
 	}
 	if b.Block.Slot > data.Slot {
 		return fmt.Errorf("could not process attestation for future block, block.Slot=%d > attestation.Data.Slot=%d", b.Block.Slot, data.Slot)
 	}
 	return nil
 }
-
-// verifyLMDFFGConsistent verifies LMD GHOST and FFG votes are consistent with each other.
-func (s *Service) verifyLMDFFGConsistent(ctx context.Context, ffgEpoch uint64, ffgRoot []byte, lmdRoot []byte) error {
-	ffgSlot := helpers.StartSlot(ffgEpoch)
-	r, err := s.ancestor(ctx, lmdRoot, ffgSlot)
-	if err != nil {
-		return err
-	}
-	if !bytes.Equal(ffgRoot, r) {
-		return errors.New("FFG and LMD votes are not consistent")
-	}
-
-	return nil
-}
-
-// verifyAttestation validates input attestation is valid.
-func (s *Service) verifyAttestation(ctx context.Context, baseState *stateTrie.BeaconState, a *ethpb.Attestation) (*ethpb.IndexedAttestation, error) {
-	committee, err := helpers.BeaconCommitteeFromState(baseState, a.Data.Slot, a.Data.CommitteeIndex)
-	if err != nil {
-		return nil, err
-	}
-	indexedAtt := attestationutil.ConvertToIndexed(ctx, a, committee)
-	if err := blocks.VerifyIndexedAttestation(ctx, baseState, indexedAtt); err != nil {
-		return nil, errors.Wrap(err, "could not verify indexed attestation")
-	}
-	return indexedAtt, nil
-}
--- a/beacon-chain/blockchain/process_attestation_test.go
+++ b/beacon-chain/blockchain/process_attestation_test.go
@@ -2,199 +2,180 @@ package blockchain

 import (
 	"context"
-	"strings"
 	"testing"

-	"github.com/gogo/protobuf/proto"
+	types "github.com/prysmaticlabs/eth2-types"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/state"
 	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
 	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateutil"
 	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+	"github.com/prysmaticlabs/prysm/shared/timeutils"
 )

-func TestStore_OnAttestation(t *testing.T) {
+func TestStore_OnAttestation_ErrorConditions(t *testing.T) {
 	ctx := context.Background()
-	db, sc := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)

 	cfg := &Config{
-		BeaconDB:        db,
+		BeaconDB:        beaconDB,
 		ForkChoiceStore: protoarray.New(0, 0, [32]byte{}),
-		StateGen:        stategen.New(db, sc),
+		StateGen:        stategen.New(beaconDB),
 	}
 	service, err := NewService(ctx, cfg)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)

-	_, err = blockTree1(db, []byte{'g'})
-	if err != nil {
-		t.Fatal(err)
-	}
+	_, err = blockTree1(t, beaconDB, []byte{'g'})
+	require.NoError(t, err)

-	BlkWithOutState := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Slot: 0}}
-	if err := db.SaveBlock(ctx, BlkWithOutState); err != nil {
-		t.Fatal(err)
-	}
-	BlkWithOutStateRoot, err := stateutil.BlockRoot(BlkWithOutState.Block)
-	if err != nil {
-		t.Fatal(err)
-	}
+	BlkWithOutState := testutil.NewBeaconBlock()
+	BlkWithOutState.Block.Slot = 0
+	require.NoError(t, beaconDB.SaveBlock(ctx, BlkWithOutState))
+	BlkWithOutStateRoot, err := BlkWithOutState.Block.HashTreeRoot()
+	require.NoError(t, err)

-	BlkWithStateBadAtt := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Slot: 1}}
-	if err := db.SaveBlock(ctx, BlkWithStateBadAtt); err != nil {
-		t.Fatal(err)
-	}
-	BlkWithStateBadAttRoot, err := stateutil.BlockRoot(BlkWithStateBadAtt.Block)
-	if err != nil {
-		t.Fatal(err)
-	}
+	BlkWithStateBadAtt := testutil.NewBeaconBlock()
+	BlkWithStateBadAtt.Block.Slot = 1
+	require.NoError(t, beaconDB.SaveBlock(ctx, BlkWithStateBadAtt))
+	BlkWithStateBadAttRoot, err := BlkWithStateBadAtt.Block.HashTreeRoot()
+	require.NoError(t, err)

-	s := testutil.NewBeaconState()
-	if err := s.SetSlot(100 * params.BeaconConfig().SlotsPerEpoch); err != nil {
-		t.Fatal(err)
-	}
-	if err := service.beaconDB.SaveState(ctx, s, BlkWithStateBadAttRoot); err != nil {
-		t.Fatal(err)
-	}
+	s, err := testutil.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, s.SetSlot(100*params.BeaconConfig().SlotsPerEpoch))
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, s, BlkWithStateBadAttRoot))

-	BlkWithValidState := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Slot: 2}}
-	if err := db.SaveBlock(ctx, BlkWithValidState); err != nil {
-		t.Fatal(err)
-	}
+	BlkWithValidState := testutil.NewBeaconBlock()
+	BlkWithValidState.Block.Slot = 2
+	require.NoError(t, beaconDB.SaveBlock(ctx, BlkWithValidState))

-	BlkWithValidStateRoot, err := stateutil.BlockRoot(BlkWithValidState.Block)
-	if err != nil {
-		t.Fatal(err)
-	}
-	s = testutil.NewBeaconState()
-	if err := s.SetFork(&pb.Fork{
+	BlkWithValidStateRoot, err := BlkWithValidState.Block.HashTreeRoot()
+	require.NoError(t, err)
+	s, err = testutil.NewBeaconState()
+	require.NoError(t, err)
+	err = s.SetFork(&pb.Fork{
 		Epoch:           0,
 		CurrentVersion:  params.BeaconConfig().GenesisForkVersion,
 		PreviousVersion: params.BeaconConfig().GenesisForkVersion,
-	}); err != nil {
-		t.Fatal(err)
-	}
-	if err := service.beaconDB.SaveState(ctx, s, BlkWithValidStateRoot); err != nil {
-		t.Fatal(err)
-	}
+	})
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, s, BlkWithValidStateRoot))

 	tests := []struct {
-		name          string
-		a             *ethpb.Attestation
-		s             *pb.BeaconState
-		wantErr       bool
-		wantErrString string
+		name      string
+		a         *ethpb.Attestation
+		wantedErr string
 	}{
 		{
-			name:          "attestation's data slot not aligned with target vote",
-			a:             &ethpb.Attestation{Data: &ethpb.AttestationData{Slot: params.BeaconConfig().SlotsPerEpoch, Target: &ethpb.Checkpoint{}}},
-			s:             &pb.BeaconState{},
-			wantErr:       true,
-			wantErrString: "data slot is not in the same epoch as target 1 != 0",
+			name:      "attestation's data slot not aligned with target vote",
+			a:         testutil.HydrateAttestation(&ethpb.Attestation{Data: &ethpb.AttestationData{Slot: params.BeaconConfig().SlotsPerEpoch, Target: &ethpb.Checkpoint{Root: make([]byte, 32)}}}),
+			wantedErr: "slot 32 does not match target epoch 0",
 		},
 		{
-			name:          "attestation's target root not in db",
-			a:             &ethpb.Attestation{Data: &ethpb.AttestationData{Target: &ethpb.Checkpoint{Root: []byte{'A'}}}},
-			s:             &pb.BeaconState{},
-			wantErr:       true,
-			wantErrString: "target root does not exist in db",
-		},
-		{
-			name:          "no pre state for attestations's target block",
-			a:             &ethpb.Attestation{Data: &ethpb.AttestationData{Target: &ethpb.Checkpoint{Root: BlkWithOutStateRoot[:]}}},
-			s:             &pb.BeaconState{},
-			wantErr:       true,
-			wantErrString: "could not get pre state for slot 0",
+			name:      "no pre state for attestations's target block",
+			a:         testutil.HydrateAttestation(&ethpb.Attestation{Data: &ethpb.AttestationData{Target: &ethpb.Checkpoint{Root: BlkWithOutStateRoot[:]}}}),
+			wantedErr: "could not get pre state for epoch 0",
 		},
 		{
 			name: "process attestation doesn't match current epoch",
-			a: &ethpb.Attestation{Data: &ethpb.AttestationData{Slot: 100 * params.BeaconConfig().SlotsPerEpoch, Target: &ethpb.Checkpoint{Epoch: 100,
-				Root: BlkWithStateBadAttRoot[:]}}},
-			s:             &pb.BeaconState{Slot: 100 * params.BeaconConfig().SlotsPerEpoch},
-			wantErr:       true,
-			wantErrString: "does not match current epoch",
+			a: testutil.HydrateAttestation(&ethpb.Attestation{Data: &ethpb.AttestationData{Slot: 100 * params.BeaconConfig().SlotsPerEpoch, Target: &ethpb.Checkpoint{Epoch: 100,
+				Root: BlkWithStateBadAttRoot[:]}}}),
+			wantedErr: "target epoch 100 does not match current epoch",
 		},
 		{
-			name:          "process nil field (a.Target) in attestation",
-			a:             nil,
-			s:             &pb.BeaconState{},
-			wantErr:       true,
-			wantErrString: "nil attestation",
+			name:      "process nil attestation",
+			a:         nil,
+			wantedErr: "attestation can't be nil",
 		},
 		{
-			name:          "process nil field (a.Data) in attestation",
-			a:             &ethpb.Attestation{},
-			s:             &pb.BeaconState{},
-			wantErr:       true,
-			wantErrString: "nil attestation.Data field",
+			name:      "process nil field (a.Data) in attestation",
+			a:         &ethpb.Attestation{},
+			wantedErr: "attestation's data can't be nil",
 		},
 		{
-			name:          "process nil field (a.Target) in attestation",
-			a:             &ethpb.Attestation{Data: &ethpb.AttestationData{}},
-			s:             &pb.BeaconState{},
-			wantErr:       true,
-			wantErrString: "nil attestation.Data.Target field",
+			name: "process nil field (a.Target) in attestation",
+			a: &ethpb.Attestation{
+				Data: &ethpb.AttestationData{
+					BeaconBlockRoot: make([]byte, 32),
+					Target:          nil,
+					Source:          &ethpb.Checkpoint{Root: make([]byte, 32)},
+				},
+				AggregationBits: make([]byte, 1),
+				Signature:       make([]byte, 96),
+			},
+			wantedErr: "attestation's target can't be nil",
 		},
 	}

 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			_, err := service.onAttestation(ctx, tt.a)
-			if tt.wantErr {
-				if err == nil || !strings.Contains(err.Error(), tt.wantErrString) {
-					t.Errorf("Store.onAttestation() error = %v, wantErr = %v", err, tt.wantErrString)
-				}
+			err := service.onAttestation(ctx, tt.a)
+			if tt.wantedErr != "" {
+				assert.ErrorContains(t, tt.wantedErr, err)
 			} else {
-				t.Error(err)
+				assert.NoError(t, err)
 			}
 		})
 	}
 }

-func TestStore_SaveCheckpointState(t *testing.T) {
+func TestStore_OnAttestation_Ok(t *testing.T) {
 	ctx := context.Background()
-	db, sc := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)

 	cfg := &Config{
-		BeaconDB: db,
-		StateGen: stategen.New(db, sc),
+		BeaconDB:        beaconDB,
+		ForkChoiceStore: protoarray.New(0, 0, [32]byte{}),
+		StateGen:        stategen.New(beaconDB),
 	}
 	service, err := NewService(ctx, cfg)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
+	genesisState, pks := testutil.DeterministicGenesisState(t, 64)
+	require.NoError(t, genesisState.SetGenesisTime(uint64(timeutils.Now().Unix())-params.BeaconConfig().SecondsPerSlot))
+	require.NoError(t, service.saveGenesisData(ctx, genesisState))
+	att, err := testutil.GenerateAttestations(genesisState, pks, 1, 0, false)
+	require.NoError(t, err)
+	tRoot := bytesutil.ToBytes32(att[0].Data.Target.Root)
+	copied := genesisState.Copy()
+	copied, err = state.ProcessSlots(ctx, copied, 1)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, copied, tRoot))
+	require.NoError(t, service.cfg.ForkChoiceStore.ProcessBlock(ctx, 0, tRoot, tRoot, tRoot, 1, 1))
+	require.NoError(t, service.onAttestation(ctx, att[0]))
+}

-	s, err := stateTrie.InitializeFromProto(&pb.BeaconState{
-		Fork: &pb.Fork{
-			Epoch:           0,
-			CurrentVersion:  params.BeaconConfig().GenesisForkVersion,
-			PreviousVersion: params.BeaconConfig().GenesisForkVersion,
-		},
-		RandaoMixes:         make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
-		StateRoots:          make([][]byte, params.BeaconConfig().SlotsPerHistoricalRoot),
-		BlockRoots:          make([][]byte, params.BeaconConfig().SlotsPerHistoricalRoot),
-		LatestBlockHeader:   &ethpb.BeaconBlockHeader{},
-		JustificationBits:   []byte{0},
-		Slashings:           make([]uint64, params.BeaconConfig().EpochsPerSlashingsVector),
-		FinalizedCheckpoint: &ethpb.Checkpoint{Root: bytesutil.PadTo([]byte{'A'}, 32)},
-		Validators:          []*ethpb.Validator{{PublicKey: bytesutil.PadTo([]byte("foo"), 48)}},
-		Balances:            []uint64{0},
-	})
-	if err != nil {
-		t.Fatal(err)
+func TestStore_SaveCheckpointState(t *testing.T) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+
+	cfg := &Config{
+		BeaconDB: beaconDB,
+		StateGen: stategen.New(beaconDB),
 	}
+	service, err := NewService(ctx, cfg)
+	require.NoError(t, err)
+
+	s, err := testutil.NewBeaconState()
+	require.NoError(t, err)
+	err = s.SetFinalizedCheckpoint(&ethpb.Checkpoint{Root: bytesutil.PadTo([]byte{'A'}, 32)})
+	require.NoError(t, err)
+	val := &ethpb.Validator{
+		PublicKey:             bytesutil.PadTo([]byte("foo"), 48),
+		WithdrawalCredentials: bytesutil.PadTo([]byte("bar"), 32),
+	}
+	err = s.SetValidators([]*ethpb.Validator{val})
+	require.NoError(t, err)
+	err = s.SetBalances([]uint64{0})
+	require.NoError(t, err)
 	r := [32]byte{'g'}
-	if err := service.beaconDB.SaveState(ctx, s, r); err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, s, r))

 	service.justifiedCheckpt = &ethpb.Checkpoint{Root: r[:]}
 	service.bestJustifiedCheckpt = &ethpb.Checkpoint{Root: r[:]}
@@ -203,332 +184,249 @@ func TestStore_SaveCheckpointState(t *testing.T) {

 	r = bytesutil.ToBytes32([]byte{'A'})
 	cp1 := &ethpb.Checkpoint{Epoch: 1, Root: bytesutil.PadTo([]byte{'A'}, 32)}
-	if err := service.beaconDB.SaveState(ctx, s, bytesutil.ToBytes32([]byte{'A'})); err != nil {
-		t.Fatal(err)
-	}
-	if err := service.beaconDB.SaveStateSummary(ctx, &pb.StateSummary{Root: bytesutil.PadTo([]byte{'A'}, 32)}); err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, s, bytesutil.ToBytes32([]byte{'A'})))
+	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(ctx, &pb.StateSummary{Root: bytesutil.PadTo([]byte{'A'}, 32)}))
+
 	s1, err := service.getAttPreState(ctx, cp1)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if s1.Slot() != 1*params.BeaconConfig().SlotsPerEpoch {
-		t.Errorf("Wanted state slot: %d, got: %d", 1*params.BeaconConfig().SlotsPerEpoch, s1.Slot())
-	}
+	require.NoError(t, err)
+	assert.Equal(t, 1*params.BeaconConfig().SlotsPerEpoch, s1.Slot(), "Unexpected state slot")

 	cp2 := &ethpb.Checkpoint{Epoch: 2, Root: bytesutil.PadTo([]byte{'B'}, 32)}
-	if err := service.beaconDB.SaveState(ctx, s, bytesutil.ToBytes32([]byte{'B'})); err != nil {
-		t.Fatal(err)
-	}
-	if err := service.beaconDB.SaveStateSummary(ctx, &pb.StateSummary{Root: bytesutil.PadTo([]byte{'B'}, 32)}); err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, s, bytesutil.ToBytes32([]byte{'B'})))
+	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(ctx, &pb.StateSummary{Root: bytesutil.PadTo([]byte{'B'}, 32)}))
 	s2, err := service.getAttPreState(ctx, cp2)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if s2.Slot() != 2*params.BeaconConfig().SlotsPerEpoch {
-		t.Errorf("Wanted state slot: %d, got: %d", 2*params.BeaconConfig().SlotsPerEpoch, s2.Slot())
-	}
+	require.NoError(t, err)
+	assert.Equal(t, 2*params.BeaconConfig().SlotsPerEpoch, s2.Slot(), "Unexpected state slot")

 	s1, err = service.getAttPreState(ctx, cp1)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if s1.Slot() != 1*params.BeaconConfig().SlotsPerEpoch {
-		t.Errorf("Wanted state slot: %d, got: %d", 1*params.BeaconConfig().SlotsPerEpoch, s1.Slot())
-	}
+	require.NoError(t, err)
+	assert.Equal(t, 1*params.BeaconConfig().SlotsPerEpoch, s1.Slot(), "Unexpected state slot")

-	s1, err = service.checkpointState.StateByCheckpoint(cp1)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if s1.Slot() != 1*params.BeaconConfig().SlotsPerEpoch {
-		t.Errorf("Wanted state slot: %d, got: %d", 1*params.BeaconConfig().SlotsPerEpoch, s1.Slot())
-	}
+	s1, err = service.checkpointStateCache.StateByCheckpoint(cp1)
+	require.NoError(t, err)
+	assert.Equal(t, 1*params.BeaconConfig().SlotsPerEpoch, s1.Slot(), "Unexpected state slot")

-	s2, err = service.checkpointState.StateByCheckpoint(cp2)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if s2.Slot() != 2*params.BeaconConfig().SlotsPerEpoch {
-		t.Errorf("Wanted state slot: %d, got: %d", 2*params.BeaconConfig().SlotsPerEpoch, s2.Slot())
-	}
+	s2, err = service.checkpointStateCache.StateByCheckpoint(cp2)
+	require.NoError(t, err)
+	assert.Equal(t, 2*params.BeaconConfig().SlotsPerEpoch, s2.Slot(), "Unexpected state slot")

-	if err := s.SetSlot(params.BeaconConfig().SlotsPerEpoch + 1); err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, s.SetSlot(params.BeaconConfig().SlotsPerEpoch+1))
 	service.justifiedCheckpt = &ethpb.Checkpoint{Root: r[:]}
 	service.bestJustifiedCheckpt = &ethpb.Checkpoint{Root: r[:]}
 	service.finalizedCheckpt = &ethpb.Checkpoint{Root: r[:]}
 	service.prevFinalizedCheckpt = &ethpb.Checkpoint{Root: r[:]}
 	cp3 := &ethpb.Checkpoint{Epoch: 1, Root: bytesutil.PadTo([]byte{'C'}, 32)}
-	if err := service.beaconDB.SaveState(ctx, s, bytesutil.ToBytes32([]byte{'C'})); err != nil {
-		t.Fatal(err)
-	}
-	if err := service.beaconDB.SaveStateSummary(ctx, &pb.StateSummary{Root: bytesutil.PadTo([]byte{'C'}, 32)}); err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, s, bytesutil.ToBytes32([]byte{'C'})))
+	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(ctx, &pb.StateSummary{Root: bytesutil.PadTo([]byte{'C'}, 32)}))
 	s3, err := service.getAttPreState(ctx, cp3)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if s3.Slot() != s.Slot() {
-		t.Errorf("Wanted state slot: %d, got: %d", s.Slot(), s3.Slot())
-	}
+	require.NoError(t, err)
+	assert.Equal(t, s.Slot(), s3.Slot(), "Unexpected state slot")
 }

 func TestStore_UpdateCheckpointState(t *testing.T) {
 	ctx := context.Background()
-	db, sc := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)

 	cfg := &Config{
-		BeaconDB: db,
-		StateGen: stategen.New(db, sc),
+		BeaconDB: beaconDB,
+		StateGen: stategen.New(beaconDB),
 	}
 	service, err := NewService(ctx, cfg)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)

-	epoch := uint64(1)
+	epoch := types.Epoch(1)
 	baseState, _ := testutil.DeterministicGenesisState(t, 1)
-	if err := baseState.SetSlot(epoch * params.BeaconConfig().SlotsPerEpoch); err != nil {
-		t.Fatal(err)
-	}
-	checkpoint := &ethpb.Checkpoint{Epoch: epoch}
-	if err := service.beaconDB.SaveState(ctx, baseState, bytesutil.ToBytes32(checkpoint.Root)); err != nil {
-		t.Fatal(err)
-	}
+	checkpoint := &ethpb.Checkpoint{Epoch: epoch, Root: bytesutil.PadTo([]byte("hi"), 32)}
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, baseState, bytesutil.ToBytes32(checkpoint.Root)))
 	returned, err := service.getAttPreState(ctx, checkpoint)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if baseState.Slot() != returned.Slot() {
-		t.Error("Incorrectly returned base state")
-	}
+	require.NoError(t, err)
+	assert.Equal(t, params.BeaconConfig().SlotsPerEpoch.Mul(uint64(checkpoint.Epoch)), returned.Slot(), "Incorrectly returned base state")

-	cached, err := service.checkpointState.StateByCheckpoint(checkpoint)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if cached == nil {
-		t.Error("State should have been cached")
-	}
+	cached, err := service.checkpointStateCache.StateByCheckpoint(checkpoint)
+	require.NoError(t, err)
+	assert.Equal(t, returned.Slot(), cached.Slot(), "State should have been cached")

-	epoch = uint64(2)
-	newCheckpoint := &ethpb.Checkpoint{Epoch: epoch}
-	if err := service.beaconDB.SaveState(ctx, baseState, bytesutil.ToBytes32(newCheckpoint.Root)); err != nil {
-		t.Fatal(err)
-	}
+	epoch = 2
+	newCheckpoint := &ethpb.Checkpoint{Epoch: epoch, Root: bytesutil.PadTo([]byte("bye"), 32)}
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, baseState, bytesutil.ToBytes32(newCheckpoint.Root)))
 	returned, err = service.getAttPreState(ctx, newCheckpoint)
-	if err != nil {
-		t.Fatal(err)
-	}
-	baseState, err = state.ProcessSlots(ctx, baseState, helpers.StartSlot(newCheckpoint.Epoch))
-	if err != nil {
-		t.Fatal(err)
-	}
-	if baseState.Slot() != returned.Slot() {
-		t.Error("Incorrectly returned base state")
-	}
+	require.NoError(t, err)
+	s, err := helpers.StartSlot(newCheckpoint.Epoch)
+	require.NoError(t, err)
+	baseState, err = state.ProcessSlots(ctx, baseState, s)
+	require.NoError(t, err)
+	assert.Equal(t, returned.Slot(), baseState.Slot(), "Incorrectly returned base state")

-	cached, err = service.checkpointState.StateByCheckpoint(newCheckpoint)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !proto.Equal(returned.InnerStateUnsafe(), cached.InnerStateUnsafe()) {
-		t.Error("Incorrectly cached base state")
-	}
+	cached, err = service.checkpointStateCache.StateByCheckpoint(newCheckpoint)
+	require.NoError(t, err)
+	require.DeepSSZEqual(t, returned.InnerStateUnsafe(), cached.InnerStateUnsafe())
 }

 func TestAttEpoch_MatchPrevEpoch(t *testing.T) {
 	ctx := context.Background()
-	db, _ := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)

-	cfg := &Config{BeaconDB: db}
+	cfg := &Config{BeaconDB: beaconDB}
 	service, err := NewService(ctx, cfg)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)

-	if err := service.verifyAttTargetEpoch(
-		ctx,
-		0,
-		params.BeaconConfig().SlotsPerEpoch*params.BeaconConfig().SecondsPerSlot,
-		&ethpb.Checkpoint{}); err != nil {
-		t.Error(err)
-	}
+	nowTime := uint64(params.BeaconConfig().SlotsPerEpoch) * params.BeaconConfig().SecondsPerSlot
+	require.NoError(t, service.verifyAttTargetEpoch(ctx, 0, nowTime, &ethpb.Checkpoint{Root: make([]byte, 32)}))
 }

 func TestAttEpoch_MatchCurrentEpoch(t *testing.T) {
 	ctx := context.Background()
-	db, _ := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)

-	cfg := &Config{BeaconDB: db}
+	cfg := &Config{BeaconDB: beaconDB}
 	service, err := NewService(ctx, cfg)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)

-	if err := service.verifyAttTargetEpoch(
-		ctx,
-		0,
-		params.BeaconConfig().SlotsPerEpoch*params.BeaconConfig().SecondsPerSlot,
-		&ethpb.Checkpoint{Epoch: 1}); err != nil {
-		t.Error(err)
-	}
+	nowTime := uint64(params.BeaconConfig().SlotsPerEpoch) * params.BeaconConfig().SecondsPerSlot
+	require.NoError(t, service.verifyAttTargetEpoch(ctx, 0, nowTime, &ethpb.Checkpoint{Epoch: 1}))
 }

 func TestAttEpoch_NotMatch(t *testing.T) {
 	ctx := context.Background()
-	db, _ := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)

-	cfg := &Config{BeaconDB: db}
+	cfg := &Config{BeaconDB: beaconDB}
 	service, err := NewService(ctx, cfg)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)

-	if err := service.verifyAttTargetEpoch(
-		ctx,
-		0,
-		2*params.BeaconConfig().SlotsPerEpoch*params.BeaconConfig().SecondsPerSlot,
-		&ethpb.Checkpoint{}); !strings.Contains(err.Error(),
-		"target epoch 0 does not match current epoch 2 or prev epoch 1") {
-		t.Error("Did not receive wanted error")
-	}
+	nowTime := 2 * uint64(params.BeaconConfig().SlotsPerEpoch) * params.BeaconConfig().SecondsPerSlot
+	err = service.verifyAttTargetEpoch(ctx, 0, nowTime, &ethpb.Checkpoint{Root: make([]byte, 32)})
+	assert.ErrorContains(t, "target epoch 0 does not match current epoch 2 or prev epoch 1", err)
 }

 func TestVerifyBeaconBlock_NoBlock(t *testing.T) {
 	ctx := context.Background()
-	db, _ := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)

-	cfg := &Config{BeaconDB: db}
+	cfg := &Config{BeaconDB: beaconDB}
 	service, err := NewService(ctx, cfg)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)

-	d := &ethpb.AttestationData{}
-	if err := service.verifyBeaconBlock(ctx, d); !strings.Contains(err.Error(), "beacon block  does not exist") {
-		t.Error("Did not receive the wanted error")
-	}
+	d := testutil.HydrateAttestationData(&ethpb.AttestationData{})
+	assert.ErrorContains(t, "signed beacon block can't be nil", service.verifyBeaconBlock(ctx, d))
 }

 func TestVerifyBeaconBlock_futureBlock(t *testing.T) {
 	ctx := context.Background()
-	db, _ := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)

-	cfg := &Config{BeaconDB: db}
+	cfg := &Config{BeaconDB: beaconDB}
 	service, err := NewService(ctx, cfg)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)

-	b := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Slot: 2}}
-	if err := service.beaconDB.SaveBlock(ctx, b); err != nil {
-		t.Fatal(err)
-	}
-	r, err := stateutil.BlockRoot(b.Block)
-	if err != nil {
-		t.Fatal(err)
-	}
+	b := testutil.NewBeaconBlock()
+	b.Block.Slot = 2
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, b))
+	r, err := b.Block.HashTreeRoot()
+	require.NoError(t, err)
 	d := &ethpb.AttestationData{Slot: 1, BeaconBlockRoot: r[:]}

-	err = service.verifyBeaconBlock(ctx, d)
-	if err == nil || !strings.Contains(err.Error(), "could not process attestation for future block") {
-		t.Error("Did not receive the wanted error")
-	}
+	assert.ErrorContains(t, "could not process attestation for future block", service.verifyBeaconBlock(ctx, d))
 }

 func TestVerifyBeaconBlock_OK(t *testing.T) {
 	ctx := context.Background()
-	db, _ := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)

-	cfg := &Config{BeaconDB: db}
+	cfg := &Config{BeaconDB: beaconDB}
 	service, err := NewService(ctx, cfg)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)

-	b := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Slot: 2}}
-	if err := service.beaconDB.SaveBlock(ctx, b); err != nil {
-		t.Fatal(err)
-	}
-	r, err := stateutil.BlockRoot(b.Block)
-	if err != nil {
-		t.Fatal(err)
-	}
+	b := testutil.NewBeaconBlock()
+	b.Block.Slot = 2
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, b))
+	r, err := b.Block.HashTreeRoot()
+	require.NoError(t, err)
 	d := &ethpb.AttestationData{Slot: 2, BeaconBlockRoot: r[:]}

-	if err := service.verifyBeaconBlock(ctx, d); err != nil {
-		t.Error("Did not receive the wanted error")
-	}
+	assert.NoError(t, service.verifyBeaconBlock(ctx, d), "Did not receive the wanted error")
 }

-func TestVerifyLMDFFGConsistent_NotOK(t *testing.T) {
+func TestVerifyFinalizedConsistency_InconsistentRoot(t *testing.T) {
 	ctx := context.Background()
-	db, _ := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)

-	cfg := &Config{BeaconDB: db}
+	cfg := &Config{BeaconDB: beaconDB, ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}
 	service, err := NewService(ctx, cfg)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)

-	b32 := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Slot: 32}}
-	if err := service.beaconDB.SaveBlock(ctx, b32); err != nil {
-		t.Fatal(err)
-	}
-	r32, err := stateutil.BlockRoot(b32.Block)
-	if err != nil {
-		t.Fatal(err)
-	}
-	b33 := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Slot: 33, ParentRoot: r32[:]}}
-	if err := service.beaconDB.SaveBlock(ctx, b33); err != nil {
-		t.Fatal(err)
-	}
-	r33, err := stateutil.BlockRoot(b33.Block)
-	if err != nil {
-		t.Fatal(err)
-	}
+	b32 := testutil.NewBeaconBlock()
+	b32.Block.Slot = 32
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, b32))
+	r32, err := b32.Block.HashTreeRoot()
+	require.NoError(t, err)

-	wanted := "FFG and LMD votes are not consistent"
-	if err := service.verifyLMDFFGConsistent(context.Background(), 1, []byte{'a'}, r33[:]); err.Error() != wanted {
-		t.Error("Did not get wanted error")
-	}
+	service.finalizedCheckpt = &ethpb.Checkpoint{Epoch: 1}
+
+	b33 := testutil.NewBeaconBlock()
+	b33.Block.Slot = 33
+	b33.Block.ParentRoot = r32[:]
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, b33))
+	r33, err := b33.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	err = service.VerifyFinalizedConsistency(context.Background(), r33[:])
+	require.ErrorContains(t, "Root and finalized store are not consistent", err)
 }

-func TestVerifyLMDFFGConsistent_OK(t *testing.T) {
+func TestVerifyFinalizedConsistency_OK(t *testing.T) {
 	ctx := context.Background()
-	db, _ := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)

-	cfg := &Config{BeaconDB: db}
+	cfg := &Config{BeaconDB: beaconDB, ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}
 	service, err := NewService(ctx, cfg)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)

-	b32 := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Slot: 32}}
-	if err := service.beaconDB.SaveBlock(ctx, b32); err != nil {
-		t.Fatal(err)
-	}
-	r32, err := stateutil.BlockRoot(b32.Block)
-	if err != nil {
-		t.Fatal(err)
-	}
-	b33 := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Slot: 33, ParentRoot: r32[:]}}
-	if err := service.beaconDB.SaveBlock(ctx, b33); err != nil {
-		t.Fatal(err)
-	}
-	r33, err := stateutil.BlockRoot(b33.Block)
-	if err != nil {
-		t.Fatal(err)
-	}
+	b32 := testutil.NewBeaconBlock()
+	b32.Block.Slot = 32
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, b32))
+	r32, err := b32.Block.HashTreeRoot()
+	require.NoError(t, err)

-	if err := service.verifyLMDFFGConsistent(context.Background(), 1, r32[:], r33[:]); err != nil {
-		t.Errorf("Could not verify LMD and FFG votes to be consistent: %v", err)
-	}
+	service.finalizedCheckpt = &ethpb.Checkpoint{Epoch: 1, Root: r32[:]}
+
+	b33 := testutil.NewBeaconBlock()
+	b33.Block.Slot = 33
+	b33.Block.ParentRoot = r32[:]
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, b33))
+	r33, err := b33.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	err = service.VerifyFinalizedConsistency(context.Background(), r33[:])
+	require.NoError(t, err)
+}
+
+func TestVerifyFinalizedConsistency_IsCanonical(t *testing.T) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+
+	cfg := &Config{BeaconDB: beaconDB, ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}
+	service, err := NewService(ctx, cfg)
+	require.NoError(t, err)
+
+	b32 := testutil.NewBeaconBlock()
+	b32.Block.Slot = 32
+	r32, err := b32.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	service.finalizedCheckpt = &ethpb.Checkpoint{Epoch: 1, Root: r32[:]}
+
+	b33 := testutil.NewBeaconBlock()
+	b33.Block.Slot = 33
+	b33.Block.ParentRoot = r32[:]
+	r33, err := b33.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	require.NoError(t, service.cfg.ForkChoiceStore.ProcessBlock(ctx, b32.Block.Slot, r32, [32]byte{}, [32]byte{}, 0, 0))
+	require.NoError(t, service.cfg.ForkChoiceStore.ProcessBlock(ctx, b33.Block.Slot, r33, r32, [32]byte{}, 0, 0))
+
+	_, err = service.cfg.ForkChoiceStore.Head(ctx, 0, r32, []uint64{}, 0)
+	require.NoError(t, err)
+	err = service.VerifyFinalizedConsistency(context.Background(), r33[:])
+	require.NoError(t, err)
 }
--- a/beacon-chain/blockchain/process_block.go
+++ b/beacon-chain/blockchain/process_block.go
@@ -2,267 +2,338 @@ package blockchain

 import (
 	"context"
-	"encoding/hex"
 	"fmt"
+	"time"

 	"github.com/pkg/errors"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/feed"
+	statefeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/state"
-	"github.com/prysmaticlabs/prysm/beacon-chain/flags"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
+	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
 	"github.com/prysmaticlabs/prysm/shared/attestationutil"
+	"github.com/prysmaticlabs/prysm/shared/bls"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/featureconfig"
 	"github.com/prysmaticlabs/prysm/shared/params"
-	"github.com/sirupsen/logrus"
 	"go.opencensus.io/trace"
 )

+// A custom slot deadline for processing state slots in our cache.
+const slotDeadline = 5 * time.Second
+
+// A custom deadline for deposit trie insertion.
+const depositDeadline = 20 * time.Second
+
 // This defines size of the upper bound for initial sync block cache.
-var initialSyncBlockCacheSize = 2 * params.BeaconConfig().SlotsPerEpoch
+var initialSyncBlockCacheSize = uint64(2 * params.BeaconConfig().SlotsPerEpoch)

 // onBlock is called when a gossip block is received. It runs regular state transition on the block.
 // The block's signing root should be computed before calling this method to avoid redundant
 // computation in this method and methods it calls into.
 //
 // Spec pseudocode definition:
-//   def on_block(store: Store, block: BeaconBlock) -> None:
-//    # Make a copy of the state to avoid mutability issues
+//   def on_block(store: Store, signed_block: SignedBeaconBlock) -> None:
+//    block = signed_block.message
+//    # Parent block must be known
 //    assert block.parent_root in store.block_states
-//    pre_state = store.block_states[block.parent_root].copy()
+//    # Make a copy of the state to avoid mutability issues
+//    pre_state = copy(store.block_states[block.parent_root])
 //    # Blocks cannot be in the future. If they are, their consideration must be delayed until the are in the past.
-//    assert store.time >= pre_state.genesis_time + block.slot * SECONDS_PER_SLOT
-//    # Add new block to the store
-//    store.blocks[signing_root(block)] = block
-//    # Check block is a descendant of the finalized block
-//    assert (
-//        get_ancestor(store, signing_root(block), store.blocks[store.finalized_checkpoint.root].slot) ==
-//        store.finalized_checkpoint.root
-//    )
-//    # Check that block is later than the finalized epoch slot
-//    assert block.slot > compute_start_slot_at_epoch(store.finalized_checkpoint.epoch)
+//    assert get_current_slot(store) >= block.slot
+//
+//    # Check that block is later than the finalized epoch slot (optimization to reduce calls to get_ancestor)
+//    finalized_slot = compute_start_slot_at_epoch(store.finalized_checkpoint.epoch)
+//    assert block.slot > finalized_slot
+//    # Check block is a descendant of the finalized block at the checkpoint finalized slot
+//    assert get_ancestor(store, block.parent_root, finalized_slot) == store.finalized_checkpoint.root
+//
 //    # Check the block is valid and compute the post-state
-//    state = state_transition(pre_state, block)
+//    state = pre_state.copy()
+//    state_transition(state, signed_block, True)
+//    # Add new block to the store
+//    store.blocks[hash_tree_root(block)] = block
 //    # Add new state for this block to the store
-//    store.block_states[signing_root(block)] = state
+//    store.block_states[hash_tree_root(block)] = state
 //
 //    # Update justified checkpoint
 //    if state.current_justified_checkpoint.epoch > store.justified_checkpoint.epoch:
 //        if state.current_justified_checkpoint.epoch > store.best_justified_checkpoint.epoch:
 //            store.best_justified_checkpoint = state.current_justified_checkpoint
+//        if should_update_justified_checkpoint(store, state.current_justified_checkpoint):
+//            store.justified_checkpoint = state.current_justified_checkpoint
 //
 //    # Update finalized checkpoint
 //    if state.finalized_checkpoint.epoch > store.finalized_checkpoint.epoch:
 //        store.finalized_checkpoint = state.finalized_checkpoint
-func (s *Service) onBlock(ctx context.Context, signed *ethpb.SignedBeaconBlock, blockRoot [32]byte) (*stateTrie.BeaconState, error) {
-	ctx, span := trace.StartSpan(ctx, "blockchain.onBlock")
-	defer span.End()
-
-	if signed == nil || signed.Block == nil {
-		return nil, errors.New("nil block")
-	}
-
-	b := signed.Block
-
-	// Retrieve incoming block's pre state.
-	preState, err := s.getBlockPreState(ctx, b)
-	if err != nil {
-		return nil, err
-	}
-
-	log.WithFields(logrus.Fields{
-		"slot": b.Slot,
-		"root": fmt.Sprintf("0x%s...", hex.EncodeToString(blockRoot[:])[:8]),
-	}).Debug("Executing state transition on block")
-
-	postState, err := state.ExecuteStateTransition(ctx, preState, signed)
-	if err != nil {
-		return nil, errors.Wrap(err, "could not execute state transition")
-	}
-
-	if err := s.beaconDB.SaveBlock(ctx, signed); err != nil {
-		return nil, errors.Wrapf(err, "could not save block from slot %d", b.Slot)
-	}
-
-	if err := s.insertBlockToForkChoiceStore(ctx, b, blockRoot, postState); err != nil {
-		return nil, errors.Wrapf(err, "could not insert block %d to fork choice store", b.Slot)
-	}
-
-	if err := s.stateGen.SaveState(ctx, blockRoot, postState); err != nil {
-		return nil, errors.Wrap(err, "could not save state")
-	}
-
-	// Update justified check point.
-	if postState.CurrentJustifiedCheckpoint().Epoch > s.justifiedCheckpt.Epoch {
-		if err := s.updateJustified(ctx, postState); err != nil {
-			return nil, err
-		}
-	}
-
-	// Update finalized check point. Prune the block cache and helper caches on every new finalized epoch.
-	if postState.FinalizedCheckpointEpoch() > s.finalizedCheckpt.Epoch {
-		if err := s.beaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
-			return nil, err
-		}
-		s.clearInitSyncBlocks()
-
-		if err := s.beaconDB.SaveFinalizedCheckpoint(ctx, postState.FinalizedCheckpoint()); err != nil {
-			return nil, errors.Wrap(err, "could not save finalized checkpoint")
-		}
-
-		fRoot := bytesutil.ToBytes32(postState.FinalizedCheckpoint().Root)
-
-		// Prune proto array fork choice nodes, all nodes before finalized check point will
-		// be pruned.
-		if err := s.forkChoiceStore.Prune(ctx, fRoot); err != nil {
-			return nil, errors.Wrap(err, "could not prune proto array fork choice nodes")
-		}
-
-		s.prevFinalizedCheckpt = s.finalizedCheckpt
-		s.finalizedCheckpt = postState.FinalizedCheckpoint()
-
-		if err := s.finalizedImpliesNewJustified(ctx, postState); err != nil {
-			return nil, errors.Wrap(err, "could not save new justified")
-		}
-
-		fBlock, err := s.beaconDB.Block(ctx, fRoot)
-		if err != nil {
-			return nil, errors.Wrap(err, "could not get finalized block to migrate")
-		}
-		if err := s.stateGen.MigrateToCold(ctx, fBlock.Block.Slot, fRoot); err != nil {
-			return nil, errors.Wrap(err, "could not migrate to cold")
-		}
-	}
-
-	// Epoch boundary bookkeeping such as logging epoch summaries.
-	if postState.Slot() >= s.nextEpochBoundarySlot {
-		logEpochData(postState)
-		reportEpochMetrics(postState)
-
-		// Update committees cache at epoch boundary slot.
-		if err := helpers.UpdateCommitteeCache(postState, helpers.CurrentEpoch(postState)); err != nil {
-			return nil, err
-		}
-		if err := helpers.UpdateProposerIndicesInCache(postState, helpers.CurrentEpoch(postState)); err != nil {
-			return nil, err
-		}
-
-		s.nextEpochBoundarySlot = helpers.StartSlot(helpers.NextEpoch(postState))
-	}
-
-	// Delete the processed block attestations from attestation pool.
-	if err := s.deletePoolAtts(b.Body.Attestations); err != nil {
-		return nil, err
-	}
-
-	// Delete the processed block attester slashings from slashings pool.
-	for i := 0; i < len(b.Body.AttesterSlashings); i++ {
-		s.slashingPool.MarkIncludedAttesterSlashing(b.Body.AttesterSlashings[i])
-	}
-
-	defer reportAttestationInclusion(b)
-
-	return postState, nil
-}
-
-// onBlockInitialSyncStateTransition is called when an initial sync block is received.
-// It runs state transition on the block and without any BLS verification. The excluded BLS verification
-// includes attestation's aggregated signature. It also does not save attestations.
-// The block's signing root should be computed before calling this method to avoid redundant
-// computation in this method and methods it calls into.
-func (s *Service) onBlockInitialSyncStateTransition(ctx context.Context, signed *ethpb.SignedBeaconBlock, blockRoot [32]byte) error {
-	ctx, span := trace.StartSpan(ctx, "blockchain.onBlock")
+//
+//        # Potentially update justified if different from store
+//        if store.justified_checkpoint != state.current_justified_checkpoint:
+//            # Update justified if new justified is later than store justified
+//            if state.current_justified_checkpoint.epoch > store.justified_checkpoint.epoch:
+//                store.justified_checkpoint = state.current_justified_checkpoint
+//                return
+//
+//            # Update justified if store justified is not in chain with finalized checkpoint
+//            finalized_slot = compute_start_slot_at_epoch(store.finalized_checkpoint.epoch)
+//            ancestor_at_finalized_slot = get_ancestor(store, store.justified_checkpoint.root, finalized_slot)
+//            if ancestor_at_finalized_slot != store.finalized_checkpoint.root:
+//                store.justified_checkpoint = state.current_justified_checkpoint
+func (s *Service) onBlock(ctx context.Context, signed *ethpb.SignedBeaconBlock, blockRoot [32]byte) error {
+	ctx, span := trace.StartSpan(ctx, "blockChain.onBlock")
 	defer span.End()

 	if signed == nil || signed.Block == nil {
 		return errors.New("nil block")
 	}
-
 	b := signed.Block

-	// Retrieve incoming block's pre state.
-	preState, err := s.verifyBlkPreState(ctx, b)
+	preState, err := s.getBlockPreState(ctx, b)
 	if err != nil {
 		return err
 	}
-	// To invalidate cache for parent root because pre state will get mutated.
-	s.stateGen.DeleteHotStateInCache(bytesutil.ToBytes32(b.ParentRoot))

-	// Exit early if the pre state slot is higher than incoming block's slot.
-	if preState.Slot() >= signed.Block.Slot {
-		return nil
-	}
-
-	var postState *stateTrie.BeaconState
-	if featureconfig.Get().InitSyncNoVerify {
-		postState, err = state.ExecuteStateTransitionNoVerifyAttSigs(ctx, preState, signed)
-	} else {
-		postState, err = state.ExecuteStateTransition(ctx, preState, signed)
-	}
+	set, postState, err := state.ExecuteStateTransitionNoVerifyAnySig(ctx, preState, signed)
 	if err != nil {
 		return errors.Wrap(err, "could not execute state transition")
 	}
+	valid, err := set.Verify()
+	if err != nil {
+		return errors.Wrap(err, "could not batch verify signature")
+	}
+	if !valid {
+		return errors.New("signature in block failed to verify")
+	}
+
+	if err := s.savePostStateInfo(ctx, blockRoot, signed, postState, false /* reg sync */); err != nil {
+		return err
+	}
+
+	// Updating next slot state cache can happen in the background. It shouldn't block rest of the process.
+	if featureconfig.Get().EnableNextSlotStateCache {
+		go func() {
+			// Use a custom deadline here, since this method runs asynchronously.
+			// We ignore the parent method's context and instead create a new one
+			// with a custom deadline, therefore using the background context instead.
+			slotCtx, cancel := context.WithTimeout(context.Background(), slotDeadline)
+			defer cancel()
+			if err := state.UpdateNextSlotCache(slotCtx, blockRoot[:], postState); err != nil {
+				log.WithError(err).Debug("could not update next slot state cache")
+			}
+		}()
+	}
+
+	// Update justified check point.
+	if postState.CurrentJustifiedCheckpoint().Epoch > s.justifiedCheckpt.Epoch {
+		if err := s.updateJustified(ctx, postState); err != nil {
+			return err
+		}
+	}
+
+	newFinalized := postState.FinalizedCheckpointEpoch() > s.finalizedCheckpt.Epoch
+	if featureconfig.Get().UpdateHeadTimely {
+		if newFinalized {
+			if err := s.finalizedImpliesNewJustified(ctx, postState); err != nil {
+				return errors.Wrap(err, "could not save new justified")
+			}
+			s.prevFinalizedCheckpt = s.finalizedCheckpt
+			s.finalizedCheckpt = postState.FinalizedCheckpoint()
+		}
+
+		if err := s.updateHead(ctx, s.getJustifiedBalances()); err != nil {
+			log.WithError(err).Warn("Could not update head")
+		}
+
+		// Send notification of the processed block to the state feed.
+		s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
+			Type: statefeed.BlockProcessed,
+			Data: &statefeed.BlockProcessedData{
+				Slot:        signed.Block.Slot,
+				BlockRoot:   blockRoot,
+				SignedBlock: signed,
+				Verified:    true,
+			},
+		})
+	}
+
+	// Update finalized check point.
+	if newFinalized {
+		if err := s.updateFinalized(ctx, postState.FinalizedCheckpoint()); err != nil {
+			return err
+		}
+		fRoot := bytesutil.ToBytes32(postState.FinalizedCheckpoint().Root)
+		if err := s.cfg.ForkChoiceStore.Prune(ctx, fRoot); err != nil {
+			return errors.Wrap(err, "could not prune proto array fork choice nodes")
+		}
+		if !featureconfig.Get().UpdateHeadTimely {
+			if err := s.finalizedImpliesNewJustified(ctx, postState); err != nil {
+				return errors.Wrap(err, "could not save new justified")
+			}
+		}
+		go func() {
+			// Use a custom deadline here, since this method runs asynchronously.
+			// We ignore the parent method's context and instead create a new one
+			// with a custom deadline, therefore using the background context instead.
+			depCtx, cancel := context.WithTimeout(context.Background(), depositDeadline)
+			defer cancel()
+			if err := s.insertFinalizedDeposits(depCtx, fRoot); err != nil {
+				log.WithError(err).Error("Could not insert finalized deposits.")
+			}
+		}()
+	}
+
+	defer reportAttestationInclusion(b)
+
+	return s.handleEpochBoundary(ctx, postState)
+}
+
+func (s *Service) onBlockBatch(ctx context.Context, blks []*ethpb.SignedBeaconBlock,
+	blockRoots [][32]byte) ([]*ethpb.Checkpoint, []*ethpb.Checkpoint, error) {
+	ctx, span := trace.StartSpan(ctx, "blockChain.onBlockBatch")
+	defer span.End()
+
+	if len(blks) == 0 || len(blockRoots) == 0 {
+		return nil, nil, errors.New("no blocks provided")
+	}
+	if blks[0] == nil || blks[0].Block == nil {
+		return nil, nil, errors.New("nil block")
+	}
+	b := blks[0].Block
+
+	// Retrieve incoming block's pre state.
+	if err := s.verifyBlkPreState(ctx, b); err != nil {
+		return nil, nil, err
+	}
+	preState, err := s.cfg.StateGen.StateByRootInitialSync(ctx, bytesutil.ToBytes32(b.ParentRoot))
+	if err != nil {
+		return nil, nil, err
+	}
+	if preState == nil {
+		return nil, nil, fmt.Errorf("nil pre state for slot %d", b.Slot)
+	}
+
+	jCheckpoints := make([]*ethpb.Checkpoint, len(blks))
+	fCheckpoints := make([]*ethpb.Checkpoint, len(blks))
+	sigSet := &bls.SignatureSet{
+		Signatures: [][]byte{},
+		PublicKeys: []bls.PublicKey{},
+		Messages:   [][32]byte{},
+	}
+	var set *bls.SignatureSet
+	boundaries := make(map[[32]byte]iface.BeaconState)
+	for i, b := range blks {
+		set, preState, err = state.ExecuteStateTransitionNoVerifyAnySig(ctx, preState, b)
+		if err != nil {
+			return nil, nil, err
+		}
+		// Save potential boundary states.
+		if helpers.IsEpochStart(preState.Slot()) {
+			boundaries[blockRoots[i]] = preState.Copy()
+			if err := s.handleEpochBoundary(ctx, preState); err != nil {
+				return nil, nil, errors.Wrap(err, "could not handle epoch boundary state")
+			}
+		}
+		jCheckpoints[i] = preState.CurrentJustifiedCheckpoint()
+		fCheckpoints[i] = preState.FinalizedCheckpoint()
+		sigSet.Join(set)
+	}
+	verify, err := sigSet.Verify()
+	if err != nil {
+		return nil, nil, err
+	}
+	if !verify {
+		return nil, nil, errors.New("batch block signature verification failed")
+	}
+	for r, st := range boundaries {
+		if err := s.cfg.StateGen.SaveState(ctx, r, st); err != nil {
+			return nil, nil, err
+		}
+	}
+	// Also saves the last post state which to be used as pre state for the next batch.
+	lastB := blks[len(blks)-1]
+	lastBR := blockRoots[len(blockRoots)-1]
+	if err := s.cfg.StateGen.SaveState(ctx, lastBR, preState); err != nil {
+		return nil, nil, err
+	}
+	if err := s.saveHeadNoDB(ctx, lastB, lastBR, preState); err != nil {
+		return nil, nil, err
+	}
+	return fCheckpoints, jCheckpoints, nil
+}
+
+// handles a block after the block's batch has been verified, where we can save blocks
+// their state summaries and split them off to relative hot/cold storage.
+func (s *Service) handleBlockAfterBatchVerify(ctx context.Context, signed *ethpb.SignedBeaconBlock,
+	blockRoot [32]byte, fCheckpoint, jCheckpoint *ethpb.Checkpoint) error {
+	b := signed.Block

 	s.saveInitSyncBlock(blockRoot, signed)
-
-	if err := s.insertBlockToForkChoiceStore(ctx, b, blockRoot, postState); err != nil {
-		return errors.Wrapf(err, "could not insert block %d to fork choice store", b.Slot)
+	if err := s.insertBlockToForkChoiceStore(ctx, b, blockRoot, fCheckpoint, jCheckpoint); err != nil {
+		return err
 	}
-
-	if err := s.stateGen.SaveState(ctx, blockRoot, postState); err != nil {
-		return errors.Wrap(err, "could not save state")
-	}
-
-	if flags.Get().EnableArchive {
-		atts := signed.Block.Body.Attestations
-		if err := s.beaconDB.SaveAttestations(ctx, atts); err != nil {
-			return errors.Wrapf(err, "could not save block attestations from slot %d", b.Slot)
-		}
+	if err := s.cfg.BeaconDB.SaveStateSummary(ctx, &pb.StateSummary{
+		Slot: signed.Block.Slot,
+		Root: blockRoot[:],
+	}); err != nil {
+		return err
 	}

 	// Rate limit how many blocks (2 epochs worth of blocks) a node keeps in the memory.
 	if uint64(len(s.getInitSyncBlocks())) > initialSyncBlockCacheSize {
-		if err := s.beaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
+		if err := s.cfg.BeaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
 			return err
 		}
 		s.clearInitSyncBlocks()
 	}

+	if jCheckpoint.Epoch > s.justifiedCheckpt.Epoch {
+		if err := s.updateJustifiedInitSync(ctx, jCheckpoint); err != nil {
+			return err
+		}
+	}
+
 	// Update finalized check point. Prune the block cache and helper caches on every new finalized epoch.
-	if postState.FinalizedCheckpointEpoch() > s.finalizedCheckpt.Epoch {
-		if err := s.beaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
+	if fCheckpoint.Epoch > s.finalizedCheckpt.Epoch {
+		if err := s.updateFinalized(ctx, fCheckpoint); err != nil {
 			return err
 		}
-		s.clearInitSyncBlocks()
-
-		if err := s.beaconDB.SaveFinalizedCheckpoint(ctx, postState.FinalizedCheckpoint()); err != nil {
-			return errors.Wrap(err, "could not save finalized checkpoint")
-		}
-
-		s.prevFinalizedCheckpt = s.finalizedCheckpt
-		s.finalizedCheckpt = postState.FinalizedCheckpoint()
-
-		fRoot := bytesutil.ToBytes32(postState.FinalizedCheckpoint().Root)
-		fBlock, err := s.beaconDB.Block(ctx, fRoot)
-		if err != nil {
-			return errors.Wrap(err, "could not get finalized block to migrate")
-		}
-		if err := s.stateGen.MigrateToCold(ctx, fBlock.Block.Slot, fRoot); err != nil {
-			return errors.Wrap(err, "could not migrate to cold")
-		}
 	}
+	return nil
+}

-	// Epoch boundary bookkeeping such as logging epoch summaries.
-	if postState.Slot() >= s.nextEpochBoundarySlot {
-		reportEpochMetrics(postState)
-		s.nextEpochBoundarySlot = helpers.StartSlot(helpers.NextEpoch(postState))
+// Epoch boundary bookkeeping such as logging epoch summaries.
+func (s *Service) handleEpochBoundary(ctx context.Context, postState iface.BeaconState) error {
+	if postState.Slot()+1 == s.nextEpochBoundarySlot {
+		// Update caches for the next epoch at epoch boundary slot - 1.
+		if err := helpers.UpdateCommitteeCache(postState, helpers.NextEpoch(postState)); err != nil {
+			return err
+		}
+		copied := postState.Copy()
+		copied, err := state.ProcessSlots(ctx, copied, copied.Slot()+1)
+		if err != nil {
+			return err
+		}
+		if err := helpers.UpdateProposerIndicesInCache(copied); err != nil {
+			return err
+		}
+	} else if postState.Slot() >= s.nextEpochBoundarySlot {
+		if err := reportEpochMetrics(ctx, postState, s.head.state); err != nil {
+			return err
+		}
+		var err error
+		s.nextEpochBoundarySlot, err = helpers.StartSlot(helpers.NextEpoch(postState))
+		if err != nil {
+			return err
+		}

-		// Update committees cache at epoch boundary slot.
+		// Update caches at epoch boundary slot.
+		// The following updates have short cut to return nil cheaply if fulfilled during boundary slot - 1.
 		if err := helpers.UpdateCommitteeCache(postState, helpers.CurrentEpoch(postState)); err != nil {
 			return err
 		}
-		if err := helpers.UpdateProposerIndicesInCache(postState, helpers.CurrentEpoch(postState)); err != nil {
+		if err := helpers.UpdateProposerIndicesInCache(postState); err != nil {
 			return err
 		}
 	}
@@ -272,28 +343,58 @@ func (s *Service) onBlockInitialSyncStateTransition(ctx context.Context, signed

 // This feeds in the block and block's attestations to fork choice store. It's allows fork choice store
 // to gain information on the most current chain.
-func (s *Service) insertBlockToForkChoiceStore(ctx context.Context, blk *ethpb.BeaconBlock, root [32]byte, state *stateTrie.BeaconState) error {
-	if err := s.fillInForkChoiceMissingBlocks(ctx, blk, state); err != nil {
+func (s *Service) insertBlockAndAttestationsToForkChoiceStore(ctx context.Context, blk *ethpb.BeaconBlock, root [32]byte,
+	st iface.BeaconState) error {
+	fCheckpoint := st.FinalizedCheckpoint()
+	jCheckpoint := st.CurrentJustifiedCheckpoint()
+	if err := s.insertBlockToForkChoiceStore(ctx, blk, root, fCheckpoint, jCheckpoint); err != nil {
 		return err
 	}
-
-	// Feed in block to fork choice store.
-	if err := s.forkChoiceStore.ProcessBlock(ctx,
-		blk.Slot, root, bytesutil.ToBytes32(blk.ParentRoot), bytesutil.ToBytes32(blk.Body.Graffiti),
-		state.CurrentJustifiedCheckpoint().Epoch,
-		state.FinalizedCheckpointEpoch()); err != nil {
-		return errors.Wrap(err, "could not process block for proto array fork choice")
-	}
-
 	// Feed in block's attestations to fork choice store.
 	for _, a := range blk.Body.Attestations {
-		committee, err := helpers.BeaconCommitteeFromState(state, a.Data.Slot, a.Data.CommitteeIndex)
+		committee, err := helpers.BeaconCommitteeFromState(st, a.Data.Slot, a.Data.CommitteeIndex)
 		if err != nil {
 			return err
 		}
-		indices := attestationutil.AttestingIndices(a.AggregationBits, committee)
-		s.forkChoiceStore.ProcessAttestation(ctx, indices, bytesutil.ToBytes32(a.Data.BeaconBlockRoot), a.Data.Target.Epoch)
+		indices, err := attestationutil.AttestingIndices(a.AggregationBits, committee)
+		if err != nil {
+			return err
+		}
+		s.cfg.ForkChoiceStore.ProcessAttestation(ctx, indices, bytesutil.ToBytes32(a.Data.BeaconBlockRoot), a.Data.Target.Epoch)
+	}
+	return nil
+}
+
+func (s *Service) insertBlockToForkChoiceStore(ctx context.Context, blk *ethpb.BeaconBlock,
+	root [32]byte, fCheckpoint, jCheckpoint *ethpb.Checkpoint) error {
+	if err := s.fillInForkChoiceMissingBlocks(ctx, blk, fCheckpoint, jCheckpoint); err != nil {
+		return err
+	}
+	// Feed in block to fork choice store.
+	if err := s.cfg.ForkChoiceStore.ProcessBlock(ctx,
+		blk.Slot, root, bytesutil.ToBytes32(blk.ParentRoot), bytesutil.ToBytes32(blk.Body.Graffiti),
+		jCheckpoint.Epoch,
+		fCheckpoint.Epoch); err != nil {
+		return errors.Wrap(err, "could not process block for proto array fork choice")
+	}
+	return nil
+}
+
+// This saves post state info to DB or cache. This also saves post state info to fork choice store.
+// Post state info consists of processed block and state. Do not call this method unless the block and state are verified.
+func (s *Service) savePostStateInfo(ctx context.Context, r [32]byte, b *ethpb.SignedBeaconBlock, st iface.BeaconState, initSync bool) error {
+	ctx, span := trace.StartSpan(ctx, "blockChain.savePostStateInfo")
+	defer span.End()
+	if initSync {
+		s.saveInitSyncBlock(r, b)
+	} else if err := s.cfg.BeaconDB.SaveBlock(ctx, b); err != nil {
+		return errors.Wrapf(err, "could not save block from slot %d", b.Block.Slot)
+	}
+	if err := s.cfg.StateGen.SaveState(ctx, r, st); err != nil {
+		return errors.Wrap(err, "could not save state")
+	}
+	if err := s.insertBlockAndAttestationsToForkChoiceStore(ctx, b.Block, r, st); err != nil {
+		return errors.Wrapf(err, "could not insert block %d to fork choice store", b.Block.Slot)
 	}
-
 	return nil
 }
--- a/beacon-chain/blockchain/process_block_helpers.go
+++ b/beacon-chain/blockchain/process_block_helpers.go
@@ -6,42 +6,36 @@ import (
 	"fmt"

 	"github.com/pkg/errors"
+	types "github.com/prysmaticlabs/eth2-types"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateutil"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
 	"github.com/prysmaticlabs/prysm/shared/attestationutil"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/featureconfig"
 	"github.com/prysmaticlabs/prysm/shared/params"
-	"github.com/prysmaticlabs/prysm/shared/roughtime"
 	"github.com/prysmaticlabs/prysm/shared/traceutil"
 	"go.opencensus.io/trace"
 )

 // CurrentSlot returns the current slot based on time.
-func (s *Service) CurrentSlot() uint64 {
-	now := roughtime.Now().Unix()
-	genesis := s.genesisTime.Unix()
-	if now < genesis {
-		return 0
-	}
-	return uint64(now-genesis) / params.BeaconConfig().SecondsPerSlot
+func (s *Service) CurrentSlot() types.Slot {
+	return helpers.CurrentSlot(uint64(s.genesisTime.Unix()))
 }

 // getBlockPreState returns the pre state of an incoming block. It uses the parent root of the block
 // to retrieve the state in DB. It verifies the pre state's validity and the incoming block
 // is in the correct time window.
-func (s *Service) getBlockPreState(ctx context.Context, b *ethpb.BeaconBlock) (*stateTrie.BeaconState, error) {
-	ctx, span := trace.StartSpan(ctx, "forkchoice.getBlockPreState")
+func (s *Service) getBlockPreState(ctx context.Context, b *ethpb.BeaconBlock) (iface.BeaconState, error) {
+	ctx, span := trace.StartSpan(ctx, "blockChain.getBlockPreState")
 	defer span.End()

 	// Verify incoming block has a valid pre state.
-	preState, err := s.verifyBlkPreState(ctx, b)
-	if err != nil {
+	if err := s.verifyBlkPreState(ctx, b); err != nil {
 		return nil, err
 	}

-	preState, err = s.stateGen.StateByRoot(ctx, bytesutil.ToBytes32(b.ParentRoot))
+	preState, err := s.cfg.StateGen.StateByRoot(ctx, bytesutil.ToBytes32(b.ParentRoot))
 	if err != nil {
 		return nil, errors.Wrapf(err, "could not get pre state for slot %d", b.Slot)
 	}
@@ -54,11 +48,6 @@ func (s *Service) getBlockPreState(ctx context.Context, b *ethpb.BeaconBlock) (*
 		return nil, err
 	}

-	// Verify block is a descendent of a finalized block.
-	if err := s.verifyBlkDescendant(ctx, bytesutil.ToBytes32(b.ParentRoot), b.Slot); err != nil {
-		return nil, err
-	}
-
 	// Verify block is later than the finalized epoch slot.
 	if err := s.verifyBlkFinalizedSlot(b); err != nil {
 		return nil, err
@@ -68,57 +57,61 @@ func (s *Service) getBlockPreState(ctx context.Context, b *ethpb.BeaconBlock) (*
 }

 // verifyBlkPreState validates input block has a valid pre-state.
-func (s *Service) verifyBlkPreState(ctx context.Context, b *ethpb.BeaconBlock) (*stateTrie.BeaconState, error) {
-	ctx, span := trace.StartSpan(ctx, "chainService.verifyBlkPreState")
+func (s *Service) verifyBlkPreState(ctx context.Context, b *ethpb.BeaconBlock) error {
+	ctx, span := trace.StartSpan(ctx, "blockChain.verifyBlkPreState")
 	defer span.End()

 	parentRoot := bytesutil.ToBytes32(b.ParentRoot)
 	// Loosen the check to HasBlock because state summary gets saved in batches
 	// during initial syncing. There's no risk given a state summary object is just a
 	// a subset of the block object.
-	if !s.stateGen.StateSummaryExists(ctx, parentRoot) && !s.beaconDB.HasBlock(ctx, parentRoot) {
-		return nil, errors.New("could not reconstruct parent state")
+	if !s.cfg.BeaconDB.HasStateSummary(ctx, parentRoot) && !s.cfg.BeaconDB.HasBlock(ctx, parentRoot) {
+		return errors.New("could not reconstruct parent state")
 	}
-	if !s.stateGen.HasState(ctx, parentRoot) {
-		if err := s.beaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
-			return nil, errors.Wrap(err, "could not save initial sync blocks")
+
+	if err := s.VerifyBlkDescendant(ctx, bytesutil.ToBytes32(b.ParentRoot)); err != nil {
+		return err
+	}
+
+	has, err := s.cfg.StateGen.HasState(ctx, parentRoot)
+	if err != nil {
+		return err
+	}
+	if !has {
+		if err := s.cfg.BeaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
+			return errors.Wrap(err, "could not save initial sync blocks")
 		}
 		s.clearInitSyncBlocks()
 	}
-	preState, err := s.stateGen.StateByRootInitialSync(ctx, parentRoot)
-	if err != nil {
-		return nil, errors.Wrapf(err, "could not get pre state for slot %d", b.Slot)
-	}
-	if preState == nil {
-		return nil, errors.Wrapf(err, "nil pre state for slot %d", b.Slot)
-	}
-
-	return preState, nil // No copy needed from newly hydrated state gen object.
+	return nil
 }

-// verifyBlkDescendant validates input block root is a descendant of the
+// VerifyBlkDescendant validates input block root is a descendant of the
 // current finalized block root.
-func (s *Service) verifyBlkDescendant(ctx context.Context, root [32]byte, slot uint64) error {
-	ctx, span := trace.StartSpan(ctx, "forkchoice.verifyBlkDescendant")
+func (s *Service) VerifyBlkDescendant(ctx context.Context, root [32]byte) error {
+	ctx, span := trace.StartSpan(ctx, "blockChain.VerifyBlkDescendant")
 	defer span.End()
-
-	finalizedBlkSigned, err := s.beaconDB.Block(ctx, bytesutil.ToBytes32(s.finalizedCheckpt.Root))
-	if err != nil || finalizedBlkSigned == nil || finalizedBlkSigned.Block == nil {
-		return errors.Wrap(err, "could not get finalized block")
+	fRoot := s.ensureRootNotZeros(bytesutil.ToBytes32(s.finalizedCheckpt.Root))
+	finalizedBlkSigned, err := s.cfg.BeaconDB.Block(ctx, fRoot)
+	if err != nil {
+		return err
+	}
+	if finalizedBlkSigned == nil || finalizedBlkSigned.Block == nil {
+		return errors.New("nil finalized block")
 	}
 	finalizedBlk := finalizedBlkSigned.Block
-
 	bFinalizedRoot, err := s.ancestor(ctx, root[:], finalizedBlk.Slot)
 	if err != nil {
 		return errors.Wrap(err, "could not get finalized block root")
 	}
 	if bFinalizedRoot == nil {
-		return fmt.Errorf("no finalized block known for block from slot %d", slot)
+		return fmt.Errorf("no finalized block known for block %#x", bytesutil.Trunc(root[:]))
 	}

-	if !bytes.Equal(bFinalizedRoot, s.finalizedCheckpt.Root) {
-		err := fmt.Errorf("block from slot %d is not a descendent of the current finalized block slot %d, %#x != %#x",
-			slot, finalizedBlk.Slot, bytesutil.Trunc(bFinalizedRoot), bytesutil.Trunc(s.finalizedCheckpt.Root))
+	if !bytes.Equal(bFinalizedRoot, fRoot[:]) {
+		err := fmt.Errorf("block %#x is not a descendent of the current finalized block slot %d, %#x != %#x",
+			bytesutil.Trunc(root[:]), finalizedBlk.Slot, bytesutil.Trunc(bFinalizedRoot),
+			bytesutil.Trunc(fRoot[:]))
 		traceutil.AnnotateError(span, err)
 		return err
 	}
@@ -128,7 +121,10 @@ func (s *Service) verifyBlkDescendant(ctx context.Context, root [32]byte, slot u
 // verifyBlkFinalizedSlot validates input block is not less than or equal
 // to current finalized slot.
 func (s *Service) verifyBlkFinalizedSlot(b *ethpb.BeaconBlock) error {
-	finalizedSlot := helpers.StartSlot(s.finalizedCheckpt.Epoch)
+	finalizedSlot, err := helpers.StartSlot(s.finalizedCheckpt.Epoch)
+	if err != nil {
+		return err
+	}
 	if finalizedSlot >= b.Slot {
 		return fmt.Errorf("block is equal or earlier than finalized block, slot %d < slot %d", b.Slot, finalizedSlot)
 	}
@@ -149,7 +145,7 @@ func (s *Service) shouldUpdateCurrentJustified(ctx context.Context, newJustified
 	if s.hasInitSyncBlock(justifiedRoot) {
 		newJustifiedBlockSigned = s.getInitSyncBlock(justifiedRoot)
 	} else {
-		newJustifiedBlockSigned, err = s.beaconDB.Block(ctx, justifiedRoot)
+		newJustifiedBlockSigned, err = s.cfg.BeaconDB.Block(ctx, justifiedRoot)
 		if err != nil {
 			return false, err
 		}
@@ -159,7 +155,11 @@ func (s *Service) shouldUpdateCurrentJustified(ctx context.Context, newJustified
 	}

 	newJustifiedBlock := newJustifiedBlockSigned.Block
-	if newJustifiedBlock.Slot <= helpers.StartSlot(s.justifiedCheckpt.Epoch) {
+	jSlot, err := helpers.StartSlot(s.justifiedCheckpt.Epoch)
+	if err != nil {
+		return false, err
+	}
+	if newJustifiedBlock.Slot <= jSlot {
 		return false, nil
 	}
 	var justifiedBlockSigned *ethpb.SignedBeaconBlock
@@ -167,7 +167,7 @@ func (s *Service) shouldUpdateCurrentJustified(ctx context.Context, newJustified
 	if s.hasInitSyncBlock(cachedJustifiedRoot) {
 		justifiedBlockSigned = s.getInitSyncBlock(cachedJustifiedRoot)
 	} else {
-		justifiedBlockSigned, err = s.beaconDB.Block(ctx, cachedJustifiedRoot)
+		justifiedBlockSigned, err = s.cfg.BeaconDB.Block(ctx, cachedJustifiedRoot)
 		if err != nil {
 			return false, err
 		}
@@ -187,7 +187,7 @@ func (s *Service) shouldUpdateCurrentJustified(ctx context.Context, newJustified
 	return true, nil
 }

-func (s *Service) updateJustified(ctx context.Context, state *stateTrie.BeaconState) error {
+func (s *Service) updateJustified(ctx context.Context, state iface.ReadOnlyBeaconState) error {
 	cpt := state.CurrentJustifiedCheckpoint()
 	if cpt.Epoch > s.bestJustifiedCheckpt.Epoch {
 		s.bestJustifiedCheckpt = cpt
@@ -205,7 +205,44 @@ func (s *Service) updateJustified(ctx context.Context, state *stateTrie.BeaconSt
 		}
 	}

-	return s.beaconDB.SaveJustifiedCheckpoint(ctx, cpt)
+	return s.cfg.BeaconDB.SaveJustifiedCheckpoint(ctx, cpt)
+}
+
+// This caches input checkpoint as justified for the service struct. It rotates current justified to previous justified,
+// caches justified checkpoint balances for fork choice and save justified checkpoint in DB.
+// This method does not have defense against fork choice bouncing attack, which is why it's only recommend to be used during initial syncing.
+func (s *Service) updateJustifiedInitSync(ctx context.Context, cp *ethpb.Checkpoint) error {
+	s.prevJustifiedCheckpt = s.justifiedCheckpt
+	s.justifiedCheckpt = cp
+	if err := s.cacheJustifiedStateBalances(ctx, bytesutil.ToBytes32(s.justifiedCheckpt.Root)); err != nil {
+		return err
+	}
+
+	return s.cfg.BeaconDB.SaveJustifiedCheckpoint(ctx, cp)
+}
+
+func (s *Service) updateFinalized(ctx context.Context, cp *ethpb.Checkpoint) error {
+	// Blocks need to be saved so that we can retrieve finalized block from
+	// DB when migrating states.
+	if err := s.cfg.BeaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
+		return err
+	}
+	s.clearInitSyncBlocks()
+
+	if err := s.cfg.BeaconDB.SaveFinalizedCheckpoint(ctx, cp); err != nil {
+		return err
+	}
+	if !featureconfig.Get().UpdateHeadTimely {
+		s.prevFinalizedCheckpt = s.finalizedCheckpt
+		s.finalizedCheckpt = cp
+	}
+
+	fRoot := bytesutil.ToBytes32(cp.Root)
+	if err := s.cfg.StateGen.MigrateToCold(ctx, fRoot); err != nil {
+		return errors.Wrap(err, "could not migrate to cold")
+	}
+
+	return nil
 }

 // ancestor returns the block root of an ancestry block from the input block root.
@@ -220,8 +257,40 @@ func (s *Service) updateJustified(ctx context.Context, state *stateTrie.BeaconSt
 //    else:
 //        # root is older than queried slot, thus a skip slot. Return most recent root prior to slot
 //        return root
-func (s *Service) ancestor(ctx context.Context, root []byte, slot uint64) ([]byte, error) {
-	ctx, span := trace.StartSpan(ctx, "forkchoice.ancestor")
+func (s *Service) ancestor(ctx context.Context, root []byte, slot types.Slot) ([]byte, error) {
+	ctx, span := trace.StartSpan(ctx, "blockChain.ancestor")
+	defer span.End()
+
+	r := bytesutil.ToBytes32(root)
+	// Get ancestor root from fork choice store instead of recursively looking up blocks in DB.
+	// This is most optimal outcome.
+	ar, err := s.ancestorByForkChoiceStore(ctx, r, slot)
+	if err != nil {
+		// Try getting ancestor root from DB when failed to retrieve from fork choice store.
+		// This is the second line of defense for retrieving ancestor root.
+		ar, err = s.ancestorByDB(ctx, r, slot)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return ar, nil
+}
+
+// This retrieves an ancestor root using fork choice store. The look up is looping through the a flat array structure.
+func (s *Service) ancestorByForkChoiceStore(ctx context.Context, r [32]byte, slot types.Slot) ([]byte, error) {
+	ctx, span := trace.StartSpan(ctx, "blockChain.ancestorByForkChoiceStore")
+	defer span.End()
+
+	if !s.cfg.ForkChoiceStore.HasParent(r) {
+		return nil, errors.New("could not find root in fork choice store")
+	}
+	return s.cfg.ForkChoiceStore.AncestorRoot(ctx, r, slot)
+}
+
+// This retrieves an ancestor root using DB. The look up is recursively looking up DB. Slower than `ancestorByForkChoiceStore`.
+func (s *Service) ancestorByDB(ctx context.Context, r [32]byte, slot types.Slot) ([]byte, error) {
+	ctx, span := trace.StartSpan(ctx, "blockChain.ancestorByDB")
 	defer span.End()

 	// Stop recursive ancestry lookup if context is cancelled.
@@ -229,25 +298,24 @@ func (s *Service) ancestor(ctx context.Context, root []byte, slot uint64) ([]byt
 		return nil, ctx.Err()
 	}

-	signed, err := s.beaconDB.Block(ctx, bytesutil.ToBytes32(root))
+	signed, err := s.cfg.BeaconDB.Block(ctx, r)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not get ancestor block")
 	}

-	if s.hasInitSyncBlock(bytesutil.ToBytes32(root)) {
-		signed = s.getInitSyncBlock(bytesutil.ToBytes32(root))
+	if s.hasInitSyncBlock(r) {
+		signed = s.getInitSyncBlock(r)
 	}

 	if signed == nil || signed.Block == nil {
 		return nil, errors.New("nil block")
 	}
 	b := signed.Block
-
 	if b.Slot == slot || b.Slot < slot {
-		return root, nil
+		return r[:], nil
 	}

-	return s.ancestor(ctx, b.ParentRoot, slot)
+	return s.ancestorByDB(ctx, bytesutil.ToBytes32(b.ParentRoot), slot)
 }

 // This updates justified check point in store, if the new justified is later than stored justified or
@@ -265,19 +333,19 @@ func (s *Service) ancestor(ctx context.Context, root []byte, slot uint64) ([]byt
 //            ancestor_at_finalized_slot = get_ancestor(store, store.justified_checkpoint.root, finalized_slot)
 //            if ancestor_at_finalized_slot != store.finalized_checkpoint.root:
 //                store.justified_checkpoint = state.current_justified_checkpoint
-func (s *Service) finalizedImpliesNewJustified(ctx context.Context, state *stateTrie.BeaconState) error {
+func (s *Service) finalizedImpliesNewJustified(ctx context.Context, state iface.BeaconState) error {
 	// Update justified if it's different than the one cached in the store.
 	if !attestationutil.CheckPointIsEqual(s.justifiedCheckpt, state.CurrentJustifiedCheckpoint()) {
 		if state.CurrentJustifiedCheckpoint().Epoch > s.justifiedCheckpt.Epoch {
 			s.justifiedCheckpt = state.CurrentJustifiedCheckpoint()
-			if err := s.cacheJustifiedStateBalances(ctx, bytesutil.ToBytes32(s.justifiedCheckpt.Root)); err != nil {
-				return err
-			}
-			return nil
+			return s.cacheJustifiedStateBalances(ctx, bytesutil.ToBytes32(s.justifiedCheckpt.Root))
 		}

 		// Update justified if store justified is not in chain with finalized check point.
-		finalizedSlot := helpers.StartSlot(s.finalizedCheckpt.Epoch)
+		finalizedSlot, err := helpers.StartSlot(s.finalizedCheckpt.Epoch)
+		if err != nil {
+			return err
+		}
 		justifiedRoot := s.ensureRootNotZeros(bytesutil.ToBytes32(s.justifiedCheckpt.Root))
 		anc, err := s.ancestor(ctx, justifiedRoot[:], finalizedSlot)
 		if err != nil {
@@ -295,39 +363,43 @@ func (s *Service) finalizedImpliesNewJustified(ctx context.Context, state *state

 // This retrieves missing blocks from DB (ie. the blocks that couldn't be received over sync) and inserts them to fork choice store.
 // This is useful for block tree visualizer and additional vote accounting.
-func (s *Service) fillInForkChoiceMissingBlocks(ctx context.Context, blk *ethpb.BeaconBlock, state *stateTrie.BeaconState) error {
+func (s *Service) fillInForkChoiceMissingBlocks(ctx context.Context, blk *ethpb.BeaconBlock,
+	fCheckpoint, jCheckpoint *ethpb.Checkpoint) error {
 	pendingNodes := make([]*ethpb.BeaconBlock, 0)
+	pendingRoots := make([][32]byte, 0)

 	parentRoot := bytesutil.ToBytes32(blk.ParentRoot)
 	slot := blk.Slot
 	// Fork choice only matters from last finalized slot.
-	higherThanFinalized := slot > helpers.StartSlot(s.finalizedCheckpt.Epoch)
+	fSlot, err := helpers.StartSlot(s.finalizedCheckpt.Epoch)
+	if err != nil {
+		return err
+	}
+	higherThanFinalized := slot > fSlot
 	// As long as parent node is not in fork choice store, and parent node is in DB.
-	for !s.forkChoiceStore.HasNode(parentRoot) && s.beaconDB.HasBlock(ctx, parentRoot) && higherThanFinalized {
-		b, err := s.beaconDB.Block(ctx, parentRoot)
+	for !s.cfg.ForkChoiceStore.HasNode(parentRoot) && s.cfg.BeaconDB.HasBlock(ctx, parentRoot) && higherThanFinalized {
+		b, err := s.cfg.BeaconDB.Block(ctx, parentRoot)
 		if err != nil {
 			return err
 		}

 		pendingNodes = append(pendingNodes, b.Block)
+		copiedRoot := parentRoot
+		pendingRoots = append(pendingRoots, copiedRoot)
 		parentRoot = bytesutil.ToBytes32(b.Block.ParentRoot)
 		slot = b.Block.Slot
-		higherThanFinalized = slot > helpers.StartSlot(s.finalizedCheckpt.Epoch)
+		higherThanFinalized = slot > fSlot
 	}

 	// Insert parent nodes to fork choice store in reverse order.
 	// Lower slots should be at the end of the list.
 	for i := len(pendingNodes) - 1; i >= 0; i-- {
 		b := pendingNodes[i]
-		r, err := stateutil.BlockRoot(b)
-		if err != nil {
-			return err
-		}
-
-		if err := s.forkChoiceStore.ProcessBlock(ctx,
+		r := pendingRoots[i]
+		if err := s.cfg.ForkChoiceStore.ProcessBlock(ctx,
 			b.Slot, r, bytesutil.ToBytes32(b.ParentRoot), bytesutil.ToBytes32(b.Body.Graffiti),
-			state.CurrentJustifiedCheckpoint().Epoch,
-			state.FinalizedCheckpointEpoch()); err != nil {
+			jCheckpoint.Epoch,
+			fCheckpoint.Epoch); err != nil {
 			return errors.Wrap(err, "could not process block for proto array fork choice")
 		}
 	}
@@ -335,15 +407,37 @@ func (s *Service) fillInForkChoiceMissingBlocks(ctx context.Context, blk *ethpb.
 	return nil
 }

+// inserts finalized deposits into our finalized deposit trie.
+func (s *Service) insertFinalizedDeposits(ctx context.Context, fRoot [32]byte) error {
+	ctx, span := trace.StartSpan(ctx, "blockChain.insertFinalizedDeposits")
+	defer span.End()
+
+	// Update deposit cache.
+	finalizedState, err := s.cfg.StateGen.StateByRoot(ctx, fRoot)
+	if err != nil {
+		return errors.Wrap(err, "could not fetch finalized state")
+	}
+	// We update the cache up to the last deposit index in the finalized block's state.
+	// We can be confident that these deposits will be included in some block
+	// because the Eth1 follow distance makes such long-range reorgs extremely unlikely.
+	eth1DepositIndex := int64(finalizedState.Eth1Data().DepositCount - 1)
+	s.cfg.DepositCache.InsertFinalizedDeposits(ctx, eth1DepositIndex)
+	// Deposit proofs are only used during state transition and can be safely removed to save space.
+	if err = s.cfg.DepositCache.PruneProofs(ctx, eth1DepositIndex); err != nil {
+		return errors.Wrap(err, "could not prune deposit proofs")
+	}
+	return nil
+}
+
 // The deletes input attestations from the attestation pool, so proposers don't include them in a block for the future.
 func (s *Service) deletePoolAtts(atts []*ethpb.Attestation) error {
 	for _, att := range atts {
 		if helpers.IsAggregated(att) {
-			if err := s.attPool.DeleteAggregatedAttestation(att); err != nil {
+			if err := s.cfg.AttPool.DeleteAggregatedAttestation(att); err != nil {
 				return err
 			}
 		} else {
-			if err := s.attPool.DeleteUnaggregatedAttestation(att); err != nil {
+			if err := s.cfg.AttPool.DeleteUnaggregatedAttestation(att); err != nil {
 				return err
 			}
 		}
--- a/beacon-chain/blockchain/process_block_test.go
+++ b/beacon-chain/blockchain/process_block_test.go
--- a/beacon-chain/blockchain/receive_attestation.go
+++ b/beacon-chain/blockchain/receive_attestation.go
@@ -1,19 +1,18 @@
 package blockchain

 import (
+	"bytes"
 	"context"
 	"fmt"
+	"time"

 	"github.com/pkg/errors"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/feed"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
-	"github.com/prysmaticlabs/prysm/shared/featureconfig"
 	"github.com/prysmaticlabs/prysm/shared/params"
-	"github.com/prysmaticlabs/prysm/shared/roughtime"
 	"github.com/prysmaticlabs/prysm/shared/slotutil"
 	"github.com/sirupsen/logrus"
 	"go.opencensus.io/trace"
@@ -22,8 +21,9 @@ import (
 // AttestationReceiver interface defines the methods of chain service receive and processing new attestations.
 type AttestationReceiver interface {
 	ReceiveAttestationNoPubsub(ctx context.Context, att *ethpb.Attestation) error
-	IsValidAttestation(ctx context.Context, att *ethpb.Attestation) bool
-	AttestationPreState(ctx context.Context, att *ethpb.Attestation) (*state.BeaconState, error)
+	AttestationPreState(ctx context.Context, att *ethpb.Attestation) (iface.BeaconState, error)
+	VerifyLmdFfgConsistency(ctx context.Context, att *ethpb.Attestation) error
+	VerifyFinalizedConsistency(ctx context.Context, root []byte) error
 }

 // ReceiveAttestationNoPubsub is a function that defines the operations that are performed on
@@ -35,115 +35,137 @@ func (s *Service) ReceiveAttestationNoPubsub(ctx context.Context, att *ethpb.Att
 	ctx, span := trace.StartSpan(ctx, "beacon-chain.blockchain.ReceiveAttestationNoPubsub")
 	defer span.End()

-	_, err := s.onAttestation(ctx, att)
-	if err != nil {
+	if err := s.onAttestation(ctx, att); err != nil {
 		return errors.Wrap(err, "could not process attestation")
 	}

-	if !featureconfig.Get().DisableUpdateHeadPerAttestation {
-		// This updates fork choice head, if a new head could not be updated due to
-		// long range or intermediate forking. It simply logs a warning and returns nil
-		// as that's more appropriate than returning errors.
-		if err := s.updateHead(ctx, s.getJustifiedBalances()); err != nil {
-			log.Warnf("Resolving fork due to new attestation: %v", err)
-			return nil
-		}
-	}
-
 	return nil
 }

-// IsValidAttestation returns true if the attestation can be verified against its pre-state.
-func (s *Service) IsValidAttestation(ctx context.Context, att *ethpb.Attestation) bool {
-	baseState, err := s.AttestationPreState(ctx, att)
-	if err != nil {
-		log.WithError(err).Error("Failed to get attestation pre state")
-		return false
-	}
-
-	if err := blocks.VerifyAttestation(ctx, baseState, att); err != nil {
-		log.WithError(err).Error("Failed to validate attestation")
-		return false
-	}
-
-	return true
-}
-
 // AttestationPreState returns the pre state of attestation.
-func (s *Service) AttestationPreState(ctx context.Context, att *ethpb.Attestation) (*state.BeaconState, error) {
+func (s *Service) AttestationPreState(ctx context.Context, att *ethpb.Attestation) (iface.BeaconState, error) {
+	ss, err := helpers.StartSlot(att.Data.Target.Epoch)
+	if err != nil {
+		return nil, err
+	}
+	if err := helpers.ValidateSlotClock(ss, uint64(s.genesisTime.Unix())); err != nil {
+		return nil, err
+	}
 	return s.getAttPreState(ctx, att.Data.Target)
 }

-// This processes attestations from the attestation pool to account for validator votes and fork choice.
-func (s *Service) processAttestation(subscribedToStateEvents chan struct{}) {
+// VerifyLmdFfgConsistency verifies that attestation's LMD and FFG votes are consistency to each other.
+func (s *Service) VerifyLmdFfgConsistency(ctx context.Context, a *ethpb.Attestation) error {
+	targetSlot, err := helpers.StartSlot(a.Data.Target.Epoch)
+	if err != nil {
+		return err
+	}
+	r, err := s.ancestor(ctx, a.Data.BeaconBlockRoot, targetSlot)
+	if err != nil {
+		return err
+	}
+	if !bytes.Equal(a.Data.Target.Root, r) {
+		return errors.New("FFG and LMD votes are not consistent")
+	}
+	return nil
+}
+
+// VerifyFinalizedConsistency verifies input root is consistent with finalized store.
+// When the input root is not be consistent with finalized store then we know it is not
+// on the finalized check point that leads to current canonical chain and should be rejected accordingly.
+func (s *Service) VerifyFinalizedConsistency(ctx context.Context, root []byte) error {
+	// A canonical root implies the root to has an ancestor that aligns with finalized check point.
+	// In this case, we could exit early to save on additional computation.
+	if s.cfg.ForkChoiceStore.IsCanonical(bytesutil.ToBytes32(root)) {
+		return nil
+	}
+
+	f := s.FinalizedCheckpt()
+	ss, err := helpers.StartSlot(f.Epoch)
+	if err != nil {
+		return err
+	}
+	r, err := s.ancestor(ctx, root, ss)
+	if err != nil {
+		return err
+	}
+	if !bytes.Equal(f.Root, r) {
+		return errors.New("Root and finalized store are not consistent")
+	}
+
+	return nil
+}
+
+// This routine processes fork choice attestations from the pool to account for validator votes and fork choice.
+func (s *Service) processAttestationsRoutine(subscribedToStateEvents chan<- struct{}) {
 	// Wait for state to be initialized.
 	stateChannel := make(chan *feed.Event, 1)
-	stateSub := s.stateNotifier.StateFeed().Subscribe(stateChannel)
+	stateSub := s.cfg.StateNotifier.StateFeed().Subscribe(stateChannel)
 	subscribedToStateEvents <- struct{}{}
 	<-stateChannel
 	stateSub.Unsubscribe()

-	st := slotutil.GetSlotTicker(s.genesisTime, params.BeaconConfig().SecondsPerSlot)
+	if s.genesisTime.IsZero() {
+		log.Warn("ProcessAttestations routine waiting for genesis time")
+		for s.genesisTime.IsZero() {
+			time.Sleep(1 * time.Second)
+		}
+		log.Warn("Genesis time received, now available to process attestations")
+	}
+
+	st := slotutil.NewSlotTicker(s.genesisTime, params.BeaconConfig().SecondsPerSlot)
 	for {
 		select {
 		case <-s.ctx.Done():
 			return
 		case <-st.C():
-			ctx := context.Background()
-			atts := s.attPool.ForkchoiceAttestations()
-			for _, a := range atts {
-				// Based on the spec, don't process the attestation until the subsequent slot.
-				// This delays consideration in the fork choice until their slot is in the past.
-				// https://github.com/ethereum/eth2.0-specs/blob/dev/specs/phase0/fork-choice.md#validate_on_attestation
-				nextSlot := a.Data.Slot + 1
-				if err := helpers.VerifySlotTime(uint64(s.genesisTime.Unix()), nextSlot, params.BeaconNetworkConfig().MaximumGossipClockDisparity); err != nil {
-					continue
-				}
-
-				hasState := s.stateGen.StateSummaryExists(ctx, bytesutil.ToBytes32(a.Data.BeaconBlockRoot))
-				hasBlock := s.hasBlock(ctx, bytesutil.ToBytes32(a.Data.BeaconBlockRoot))
-				if !(hasState && hasBlock) {
-					continue
-				}
-
-				if err := s.attPool.DeleteForkchoiceAttestation(a); err != nil {
-					log.WithError(err).Error("Could not delete fork choice attestation in pool")
-				}
-
-				if !s.verifyCheckpointEpoch(a.Data.Target) {
-					continue
-				}
-
-				if err := s.ReceiveAttestationNoPubsub(ctx, a); err != nil {
-					log.WithFields(logrus.Fields{
-						"slot":             a.Data.Slot,
-						"committeeIndex":   a.Data.CommitteeIndex,
-						"beaconBlockRoot":  fmt.Sprintf("%#x", bytesutil.Trunc(a.Data.BeaconBlockRoot)),
-						"targetRoot":       fmt.Sprintf("%#x", bytesutil.Trunc(a.Data.Target.Root)),
-						"aggregationCount": a.AggregationBits.Count(),
-					}).WithError(err).Warn("Could not receive attestation in chain service")
-				}
+			// Continue when there's no fork choice attestation, there's nothing to process and update head.
+			// This covers the condition when the node is still initial syncing to the head of the chain.
+			if s.cfg.AttPool.ForkchoiceAttestationCount() == 0 {
+				continue
+			}
+			s.processAttestations(s.ctx)
+			if err := s.updateHead(s.ctx, s.getJustifiedBalances()); err != nil {
+				log.Warnf("Resolving fork due to new attestation: %v", err)
 			}
 		}
 	}
 }

-// This verifies the epoch of input checkpoint is within current epoch and previous epoch
-// with respect to current time. Returns true if it's within, false if it's not.
-func (s *Service) verifyCheckpointEpoch(c *ethpb.Checkpoint) bool {
-	now := uint64(roughtime.Now().Unix())
-	genesisTime := uint64(s.genesisTime.Unix())
-	currentSlot := (now - genesisTime) / params.BeaconConfig().SecondsPerSlot
-	currentEpoch := helpers.SlotToEpoch(currentSlot)
+// This processes fork choice attestations from the pool to account for validator votes and fork choice.
+func (s *Service) processAttestations(ctx context.Context) {
+	atts := s.cfg.AttPool.ForkchoiceAttestations()
+	for _, a := range atts {
+		// Based on the spec, don't process the attestation until the subsequent slot.
+		// This delays consideration in the fork choice until their slot is in the past.
+		// https://github.com/ethereum/eth2.0-specs/blob/dev/specs/phase0/fork-choice.md#validate_on_attestation
+		nextSlot := a.Data.Slot + 1
+		if err := helpers.VerifySlotTime(uint64(s.genesisTime.Unix()), nextSlot, params.BeaconNetworkConfig().MaximumGossipClockDisparity); err != nil {
+			continue
+		}

-	var prevEpoch uint64
-	if currentEpoch > 1 {
-		prevEpoch = currentEpoch - 1
+		hasState := s.cfg.BeaconDB.HasStateSummary(ctx, bytesutil.ToBytes32(a.Data.BeaconBlockRoot))
+		hasBlock := s.hasBlock(ctx, bytesutil.ToBytes32(a.Data.BeaconBlockRoot))
+		if !(hasState && hasBlock) {
+			continue
+		}
+
+		if err := s.cfg.AttPool.DeleteForkchoiceAttestation(a); err != nil {
+			log.WithError(err).Error("Could not delete fork choice attestation in pool")
+		}
+
+		if !helpers.VerifyCheckpointEpoch(a.Data.Target, s.genesisTime) {
+			continue
+		}
+
+		if err := s.ReceiveAttestationNoPubsub(ctx, a); err != nil {
+			log.WithFields(logrus.Fields{
+				"slot":             a.Data.Slot,
+				"committeeIndex":   a.Data.CommitteeIndex,
+				"beaconBlockRoot":  fmt.Sprintf("%#x", bytesutil.Trunc(a.Data.BeaconBlockRoot)),
+				"targetRoot":       fmt.Sprintf("%#x", bytesutil.Trunc(a.Data.Target.Root)),
+				"aggregationCount": a.AggregationBits.Count(),
+			}).WithError(err).Warn("Could not process attestation for fork choice")
+		}
 	}
-
-	if c.Epoch != prevEpoch && c.Epoch != currentEpoch {
-		return false
-	}
-
-	return true
 }
--- a/beacon-chain/blockchain/receive_attestation_test.go
+++ b/beacon-chain/blockchain/receive_attestation_test.go
@@ -1,26 +1,121 @@
 package blockchain

 import (
+	"context"
 	"testing"
 	"time"

+	types "github.com/prysmaticlabs/eth2-types"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/state"
 	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
+	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
+	"github.com/prysmaticlabs/prysm/beacon-chain/operations/attestations"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+	"github.com/prysmaticlabs/prysm/shared/timeutils"
+	logTest "github.com/sirupsen/logrus/hooks/test"
 )

-func TestVerifyCheckpointEpoch_Ok(t *testing.T) {
+func TestAttestationCheckPtState_FarFutureSlot(t *testing.T) {
 	helpers.ClearCache()
-	db, sc := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)

-	chainService := setupBeaconChain(t, db, sc)
+	chainService := setupBeaconChain(t, beaconDB)
 	chainService.genesisTime = time.Now()

-	if !chainService.verifyCheckpointEpoch(&ethpb.Checkpoint{}) {
-		t.Error("Wanted true, got false")
-	}
-
-	if chainService.verifyCheckpointEpoch(&ethpb.Checkpoint{Epoch: 1}) {
-		t.Error("Wanted false, got true")
-	}
+	e := types.Epoch(helpers.MaxSlotBuffer/uint64(params.BeaconConfig().SlotsPerEpoch) + 1)
+	_, err := chainService.AttestationPreState(context.Background(), &ethpb.Attestation{Data: &ethpb.AttestationData{Target: &ethpb.Checkpoint{Epoch: e}}})
+	require.ErrorContains(t, "exceeds max allowed value relative to the local clock", err)
+}
+
+func TestVerifyLMDFFGConsistent_NotOK(t *testing.T) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+
+	cfg := &Config{BeaconDB: beaconDB, ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}
+	service, err := NewService(ctx, cfg)
+	require.NoError(t, err)
+
+	b32 := testutil.NewBeaconBlock()
+	b32.Block.Slot = 32
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, b32))
+	r32, err := b32.Block.HashTreeRoot()
+	require.NoError(t, err)
+	b33 := testutil.NewBeaconBlock()
+	b33.Block.Slot = 33
+	b33.Block.ParentRoot = r32[:]
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, b33))
+	r33, err := b33.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	wanted := "FFG and LMD votes are not consistent"
+	a := testutil.NewAttestation()
+	a.Data.Target.Epoch = 1
+	a.Data.Target.Root = []byte{'a'}
+	a.Data.BeaconBlockRoot = r33[:]
+	require.ErrorContains(t, wanted, service.VerifyLmdFfgConsistency(context.Background(), a))
+}
+
+func TestVerifyLMDFFGConsistent_OK(t *testing.T) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+
+	cfg := &Config{BeaconDB: beaconDB, ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}
+	service, err := NewService(ctx, cfg)
+	require.NoError(t, err)
+
+	b32 := testutil.NewBeaconBlock()
+	b32.Block.Slot = 32
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, b32))
+	r32, err := b32.Block.HashTreeRoot()
+	require.NoError(t, err)
+	b33 := testutil.NewBeaconBlock()
+	b33.Block.Slot = 33
+	b33.Block.ParentRoot = r32[:]
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, b33))
+	r33, err := b33.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	a := testutil.NewAttestation()
+	a.Data.Target.Epoch = 1
+	a.Data.Target.Root = r32[:]
+	a.Data.BeaconBlockRoot = r33[:]
+	err = service.VerifyLmdFfgConsistency(context.Background(), a)
+	require.NoError(t, err, "Could not verify LMD and FFG votes to be consistent")
+}
+
+func TestProcessAttestations_Ok(t *testing.T) {
+	hook := logTest.NewGlobal()
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+
+	cfg := &Config{
+		BeaconDB:        beaconDB,
+		ForkChoiceStore: protoarray.New(0, 0, [32]byte{}),
+		StateGen:        stategen.New(beaconDB),
+		AttPool:         attestations.NewPool(),
+	}
+	service, err := NewService(ctx, cfg)
+	service.genesisTime = timeutils.Now().Add(-1 * time.Duration(params.BeaconConfig().SecondsPerSlot) * time.Second)
+	require.NoError(t, err)
+	genesisState, pks := testutil.DeterministicGenesisState(t, 64)
+	require.NoError(t, genesisState.SetGenesisTime(uint64(timeutils.Now().Unix())-params.BeaconConfig().SecondsPerSlot))
+	require.NoError(t, service.saveGenesisData(ctx, genesisState))
+	atts, err := testutil.GenerateAttestations(genesisState, pks, 1, 0, false)
+	require.NoError(t, err)
+	tRoot := bytesutil.ToBytes32(atts[0].Data.Target.Root)
+	copied := genesisState.Copy()
+	copied, err = state.ProcessSlots(ctx, copied, 1)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, copied, tRoot))
+	require.NoError(t, service.cfg.ForkChoiceStore.ProcessBlock(ctx, 0, tRoot, tRoot, tRoot, 1, 1))
+	require.NoError(t, service.cfg.AttPool.SaveForkchoiceAttestations(atts))
+	service.processAttestations(ctx)
+	require.Equal(t, 0, len(service.cfg.AttPool.ForkchoiceAttestations()))
+	require.LogsDoNotContain(t, hook, "Could not process attestation for fork choice")
 }
--- a/beacon-chain/blockchain/receive_block.go
+++ b/beacon-chain/blockchain/receive_block.go
@@ -1,174 +1,131 @@
 package blockchain

 import (
-	"bytes"
 	"context"
-	"encoding/hex"

 	"github.com/pkg/errors"
+	types "github.com/prysmaticlabs/eth2-types"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/epoch/precompute"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/feed"
 	statefeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateV0"
 	"github.com/prysmaticlabs/prysm/shared/featureconfig"
+	"github.com/prysmaticlabs/prysm/shared/timeutils"
 	"github.com/prysmaticlabs/prysm/shared/traceutil"
-	"github.com/sirupsen/logrus"
 	"go.opencensus.io/trace"
 )

+// This defines how many epochs since finality the run time will begin to save hot state on to the DB.
+var epochsSinceFinalitySaveHotStateDB = types.Epoch(100)
+
 // BlockReceiver interface defines the methods of chain service receive and processing new blocks.
 type BlockReceiver interface {
 	ReceiveBlock(ctx context.Context, block *ethpb.SignedBeaconBlock, blockRoot [32]byte) error
-	ReceiveBlockNoPubsub(ctx context.Context, block *ethpb.SignedBeaconBlock, blockRoot [32]byte) error
-	ReceiveBlockInitialSync(ctx context.Context, block *ethpb.SignedBeaconBlock, blockRoot [32]byte) error
+	ReceiveBlockBatch(ctx context.Context, blocks []*ethpb.SignedBeaconBlock, blkRoots [][32]byte) error
 	HasInitSyncBlock(root [32]byte) bool
 }

-// ReceiveBlock is a function that defines the operations that are performed on
-// blocks that is received from rpc service. The operations consists of:
-//   1. Gossip block to other peers
-//   2. Validate block, apply state transition and update check points
-//   3. Apply fork choice to the processed block
-//   4. Save latest head info
-func (s *Service) ReceiveBlock(ctx context.Context, block *ethpb.SignedBeaconBlock, blockRoot [32]byte) error {
-	ctx, span := trace.StartSpan(ctx, "beacon-chain.blockchain.ReceiveBlock")
-	defer span.End()
-
-	// Broadcast the new block to the network.
-	if err := s.p2p.Broadcast(ctx, block); err != nil {
-		return errors.Wrap(err, "could not broadcast block")
-	}
-	log.WithFields(logrus.Fields{
-		"blockRoot": hex.EncodeToString(blockRoot[:]),
-	}).Debug("Broadcasting block")
-
-	if err := captureSentTimeMetric(uint64(s.genesisTime.Unix()), block.Block.Slot); err != nil {
-		// If a node fails to capture metric, this shouldn't cause the block processing to fail.
-		log.Warnf("Could not capture block sent time metric: %v", err)
-	}
-
-	if err := s.ReceiveBlockNoPubsub(ctx, block, blockRoot); err != nil {
-		return err
-	}
-
-	return nil
-}
-
-// ReceiveBlockNoPubsub is a function that defines the the operations (minus pubsub)
+// ReceiveBlock is a function that defines the the operations (minus pubsub)
 // that are performed on blocks that is received from regular sync service. The operations consists of:
 //   1. Validate block, apply state transition and update check points
 //   2. Apply fork choice to the processed block
 //   3. Save latest head info
-func (s *Service) ReceiveBlockNoPubsub(ctx context.Context, block *ethpb.SignedBeaconBlock, blockRoot [32]byte) error {
-	ctx, span := trace.StartSpan(ctx, "beacon-chain.blockchain.ReceiveBlockNoPubsub")
+func (s *Service) ReceiveBlock(ctx context.Context, block *ethpb.SignedBeaconBlock, blockRoot [32]byte) error {
+	ctx, span := trace.StartSpan(ctx, "blockChain.ReceiveBlock")
 	defer span.End()
-	blockCopy := stateTrie.CopySignedBeaconBlock(block)
+	receivedTime := timeutils.Now()
+	blockCopy := stateV0.CopySignedBeaconBlock(block)

 	// Apply state transition on the new block.
-	_, err := s.onBlock(ctx, blockCopy, blockRoot)
-	if err != nil {
+	if err := s.onBlock(ctx, blockCopy, blockRoot); err != nil {
 		err := errors.Wrap(err, "could not process block")
 		traceutil.AnnotateError(span, err)
 		return err
 	}

-	// Add attestations from the block to the pool for fork choice.
-	if err := s.attPool.SaveBlockAttestations(blockCopy.Block.Body.Attestations); err != nil {
-		log.Errorf("Could not save attestation for fork choice: %v", err)
-		return nil
-	}
-	for _, exit := range block.Block.Body.VoluntaryExits {
-		s.exitPool.MarkIncluded(exit)
-	}
-
-	s.epochParticipationLock.Lock()
-	defer s.epochParticipationLock.Unlock()
-	s.epochParticipation[helpers.SlotToEpoch(blockCopy.Block.Slot)] = precompute.Balances
-
-	if featureconfig.Get().DisableForkChoice && block.Block.Slot > s.headSlot() {
-		if err := s.saveHead(ctx, blockRoot); err != nil {
-			return errors.Wrap(err, "could not save head")
-		}
-	} else {
+	// Update and save head block after fork choice.
+	if !featureconfig.Get().UpdateHeadTimely {
 		if err := s.updateHead(ctx, s.getJustifiedBalances()); err != nil {
-			return errors.Wrap(err, "could not save head")
+			log.WithError(err).Warn("Could not update head")
 		}
+		// Send notification of the processed block to the state feed.
+		s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
+			Type: statefeed.BlockProcessed,
+			Data: &statefeed.BlockProcessedData{
+				Slot:        blockCopy.Block.Slot,
+				BlockRoot:   blockRoot,
+				SignedBlock: blockCopy,
+				Verified:    true,
+			},
+		})
 	}

-	// Send notification of the processed block to the state feed.
-	s.stateNotifier.StateFeed().Send(&feed.Event{
-		Type: statefeed.BlockProcessed,
-		Data: &statefeed.BlockProcessedData{
-			Slot:      blockCopy.Block.Slot,
-			BlockRoot: blockRoot,
-			Verified:  true,
-		},
-	})
+	// Handle post block operations such as attestations and exits.
+	if err := s.handlePostBlockOperations(blockCopy.Block); err != nil {
+		return err
+	}
+
+	// Have we been finalizing? Should we start saving hot states to db?
+	if err := s.checkSaveHotStateDB(ctx); err != nil {
+		return err
+	}

 	// Reports on block and fork choice metrics.
-	reportSlotMetrics(blockCopy.Block.Slot, s.headSlot(), s.CurrentSlot(), s.finalizedCheckpt)
+	reportSlotMetrics(blockCopy.Block.Slot, s.HeadSlot(), s.CurrentSlot(), s.finalizedCheckpt)

 	// Log block sync status.
-	logBlockSyncStatus(blockCopy.Block, blockRoot, s.finalizedCheckpt)
-
+	if err := logBlockSyncStatus(blockCopy.Block, blockRoot, s.finalizedCheckpt, receivedTime, uint64(s.genesisTime.Unix())); err != nil {
+		return err
+	}
 	// Log state transition data.
 	logStateTransitionData(blockCopy.Block)

 	return nil
 }

-// ReceiveBlockInitialSync processes the input block for the purpose of initial syncing.
-// This method should only be used on blocks during initial syncing phase.
-func (s *Service) ReceiveBlockInitialSync(ctx context.Context, block *ethpb.SignedBeaconBlock, blockRoot [32]byte) error {
-	ctx, span := trace.StartSpan(ctx, "beacon-chain.blockchain.ReceiveBlockNoVerify")
+// ReceiveBlockBatch processes the whole block batch at once, assuming the block batch is linear ,transitioning
+// the state, performing batch verification of all collected signatures and then performing the appropriate
+// actions for a block post-transition.
+func (s *Service) ReceiveBlockBatch(ctx context.Context, blocks []*ethpb.SignedBeaconBlock, blkRoots [][32]byte) error {
+	ctx, span := trace.StartSpan(ctx, "blockChain.ReceiveBlockBatch")
 	defer span.End()
-	blockCopy := stateTrie.CopySignedBeaconBlock(block)

 	// Apply state transition on the incoming newly received blockCopy without verifying its BLS contents.
-	if err := s.onBlockInitialSyncStateTransition(ctx, blockCopy, blockRoot); err != nil {
-		err := errors.Wrap(err, "could not process block")
+	fCheckpoints, jCheckpoints, err := s.onBlockBatch(ctx, blocks, blkRoots)
+	if err != nil {
+		err := errors.Wrap(err, "could not process block in batch")
 		traceutil.AnnotateError(span, err)
 		return err
 	}

-	cachedHeadRoot, err := s.HeadRoot(ctx)
-	if err != nil {
-		return errors.Wrap(err, "could not get head root from cache")
-	}
-
-	if !bytes.Equal(blockRoot[:], cachedHeadRoot) {
-		if err := s.saveHeadNoDB(ctx, blockCopy, blockRoot); err != nil {
-			err := errors.Wrap(err, "could not save head")
+	for i, b := range blocks {
+		blockCopy := stateV0.CopySignedBeaconBlock(b)
+		if err = s.handleBlockAfterBatchVerify(ctx, blockCopy, blkRoots[i], fCheckpoints[i], jCheckpoints[i]); err != nil {
 			traceutil.AnnotateError(span, err)
 			return err
 		}
+		// Send notification of the processed block to the state feed.
+		s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
+			Type: statefeed.BlockProcessed,
+			Data: &statefeed.BlockProcessedData{
+				Slot:        blockCopy.Block.Slot,
+				BlockRoot:   blkRoots[i],
+				SignedBlock: blockCopy,
+				Verified:    true,
+			},
+		})
+
+		// Reports on blockCopy and fork choice metrics.
+		reportSlotMetrics(blockCopy.Block.Slot, s.HeadSlot(), s.CurrentSlot(), s.finalizedCheckpt)
 	}

-	// Send notification of the processed block to the state feed.
-	s.stateNotifier.StateFeed().Send(&feed.Event{
-		Type: statefeed.BlockProcessed,
-		Data: &statefeed.BlockProcessedData{
-			Slot:      blockCopy.Block.Slot,
-			BlockRoot: blockRoot,
-			Verified:  false,
-		},
-	})
-
-	// Reports on blockCopy and fork choice metrics.
-	reportSlotMetrics(blockCopy.Block.Slot, s.headSlot(), s.CurrentSlot(), s.finalizedCheckpt)
-
-	// Log state transition data.
-	log.WithFields(logrus.Fields{
-		"slot":         blockCopy.Block.Slot,
-		"attestations": len(blockCopy.Block.Body.Attestations),
-		"deposits":     len(blockCopy.Block.Body.Deposits),
-	}).Debug("Finished applying state transition")
-
-	s.epochParticipationLock.Lock()
-	defer s.epochParticipationLock.Unlock()
-	s.epochParticipation[helpers.SlotToEpoch(blockCopy.Block.Slot)] = precompute.Balances
+	if err := s.VerifyWeakSubjectivityRoot(s.ctx); err != nil {
+		// log.Fatalf will prevent defer from being called
+		span.End()
+		// Exit run time if the node failed to verify weak subjectivity checkpoint.
+		log.Fatalf("Could not verify weak subjectivity checkpoint: %v", err)
+	}

 	return nil
 }
@@ -177,3 +134,44 @@ func (s *Service) ReceiveBlockInitialSync(ctx context.Context, block *ethpb.Sign
 func (s *Service) HasInitSyncBlock(root [32]byte) bool {
 	return s.hasInitSyncBlock(root)
 }
+
+func (s *Service) handlePostBlockOperations(b *ethpb.BeaconBlock) error {
+	// Delete the processed block attestations from attestation pool.
+	if err := s.deletePoolAtts(b.Body.Attestations); err != nil {
+		return err
+	}
+
+	// Add block attestations to the fork choice pool to compute head.
+	if err := s.cfg.AttPool.SaveBlockAttestations(b.Body.Attestations); err != nil {
+		log.Errorf("Could not save block attestations for fork choice: %v", err)
+		return nil
+	}
+	// Mark block exits as seen so we don't include same ones in future blocks.
+	for _, e := range b.Body.VoluntaryExits {
+		s.cfg.ExitPool.MarkIncluded(e)
+	}
+
+	//  Mark attester slashings as seen so we don't include same ones in future blocks.
+	for _, as := range b.Body.AttesterSlashings {
+		s.cfg.SlashingPool.MarkIncludedAttesterSlashing(as)
+	}
+	return nil
+}
+
+// This checks whether it's time to start saving hot state to DB.
+// It's time when there's `epochsSinceFinalitySaveHotStateDB` epochs of non-finality.
+func (s *Service) checkSaveHotStateDB(ctx context.Context) error {
+	currentEpoch := helpers.SlotToEpoch(s.CurrentSlot())
+	// Prevent `sinceFinality` going underflow.
+	var sinceFinality types.Epoch
+	if currentEpoch > s.finalizedCheckpt.Epoch {
+		sinceFinality = currentEpoch - s.finalizedCheckpt.Epoch
+	}
+
+	if sinceFinality >= epochsSinceFinalitySaveHotStateDB {
+		s.cfg.StateGen.EnableSaveHotStateToDB(ctx)
+		return nil
+	}
+
+	return s.cfg.StateGen.DisableSaveHotStateToDB(ctx)
+}
--- a/beacon-chain/blockchain/receive_block_test.go
+++ b/beacon-chain/blockchain/receive_block_test.go
@@ -0,0 +1,333 @@
+package blockchain
+
+import (
+	"context"
+	"sync"
+	"testing"
+	"time"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
+	blockchainTesting "github.com/prysmaticlabs/prysm/beacon-chain/blockchain/testing"
+	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
+	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
+	"github.com/prysmaticlabs/prysm/beacon-chain/operations/attestations"
+	"github.com/prysmaticlabs/prysm/beacon-chain/operations/voluntaryexits"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+	logTest "github.com/sirupsen/logrus/hooks/test"
+)
+
+func TestService_ReceiveBlock(t *testing.T) {
+	ctx := context.Background()
+
+	genesis, keys := testutil.DeterministicGenesisState(t, 64)
+	genFullBlock := func(t *testing.T, conf *testutil.BlockGenConfig, slot types.Slot) *ethpb.SignedBeaconBlock {
+		blk, err := testutil.GenerateFullBlock(genesis, keys, conf, slot)
+		assert.NoError(t, err)
+		return blk
+	}
+	bc := params.BeaconConfig()
+	bc.ShardCommitteePeriod = 0 // Required for voluntary exits test in reasonable time.
+	params.OverrideBeaconConfig(bc)
+
+	type args struct {
+		block *ethpb.SignedBeaconBlock
+	}
+	tests := []struct {
+		name      string
+		args      args
+		wantedErr string
+		check     func(*testing.T, *Service)
+	}{
+		{
+			name: "applies block with state transition",
+			args: args{
+				block: genFullBlock(t, testutil.DefaultBlockGenConfig(), 2 /*slot*/),
+			},
+			check: func(t *testing.T, s *Service) {
+				if hs := s.head.state.Slot(); hs != 2 {
+					t.Errorf("Unexpected state slot. Got %d but wanted %d", hs, 2)
+				}
+				if bs := s.head.block.Block.Slot; bs != 2 {
+					t.Errorf("Unexpected head block slot. Got %d but wanted %d", bs, 2)
+				}
+			},
+		},
+		{
+			name: "saves attestations to pool",
+			args: args{
+				block: genFullBlock(t,
+					&testutil.BlockGenConfig{
+						NumProposerSlashings: 0,
+						NumAttesterSlashings: 0,
+						NumAttestations:      2,
+						NumDeposits:          0,
+						NumVoluntaryExits:    0,
+					},
+					1, /*slot*/
+				),
+			},
+			check: func(t *testing.T, s *Service) {
+				if baCount := len(s.cfg.AttPool.BlockAttestations()); baCount != 2 {
+					t.Errorf("Did not get the correct number of block attestations saved to the pool. "+
+						"Got %d but wanted %d", baCount, 2)
+				}
+			},
+		},
+		{
+			name: "updates exit pool",
+			args: args{
+				block: genFullBlock(t, &testutil.BlockGenConfig{
+					NumProposerSlashings: 0,
+					NumAttesterSlashings: 0,
+					NumAttestations:      0,
+					NumDeposits:          0,
+					NumVoluntaryExits:    3,
+				},
+					1, /*slot*/
+				),
+			},
+			check: func(t *testing.T, s *Service) {
+				pending := s.cfg.ExitPool.PendingExits(genesis, 1, true /* no limit */)
+				if len(pending) != 0 {
+					t.Errorf(
+						"Did not mark the correct number of exits. Got %d pending but wanted %d",
+						len(pending),
+						0,
+					)
+				}
+			},
+		},
+		{
+			name: "notifies block processed on state feed",
+			args: args{
+				block: genFullBlock(t, testutil.DefaultBlockGenConfig(), 1 /*slot*/),
+			},
+			check: func(t *testing.T, s *Service) {
+				if recvd := len(s.cfg.StateNotifier.(*blockchainTesting.MockStateNotifier).ReceivedEvents()); recvd < 1 {
+					t.Errorf("Received %d state notifications, expected at least 1", recvd)
+				}
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			beaconDB := testDB.SetupDB(t)
+			genesisBlockRoot := bytesutil.ToBytes32(nil)
+			require.NoError(t, beaconDB.SaveState(ctx, genesis, genesisBlockRoot))
+
+			cfg := &Config{
+				BeaconDB: beaconDB,
+				ForkChoiceStore: protoarray.New(
+					0, // justifiedEpoch
+					0, // finalizedEpoch
+					genesisBlockRoot,
+				),
+				AttPool:       attestations.NewPool(),
+				ExitPool:      voluntaryexits.NewPool(),
+				StateNotifier: &blockchainTesting.MockStateNotifier{RecordEvents: true},
+				StateGen:      stategen.New(beaconDB),
+			}
+			s, err := NewService(ctx, cfg)
+			require.NoError(t, err)
+			require.NoError(t, s.saveGenesisData(ctx, genesis))
+			gBlk, err := s.cfg.BeaconDB.GenesisBlock(ctx)
+			require.NoError(t, err)
+			gRoot, err := gBlk.Block.HashTreeRoot()
+			require.NoError(t, err)
+			s.finalizedCheckpt = &ethpb.Checkpoint{Root: gRoot[:]}
+			root, err := tt.args.block.Block.HashTreeRoot()
+			require.NoError(t, err)
+			err = s.ReceiveBlock(ctx, tt.args.block, root)
+			if tt.wantedErr != "" {
+				assert.ErrorContains(t, tt.wantedErr, err)
+			} else {
+				assert.NoError(t, err)
+				tt.check(t, s)
+			}
+		})
+	}
+}
+
+func TestService_ReceiveBlockUpdateHead(t *testing.T) {
+	ctx := context.Background()
+	genesis, keys := testutil.DeterministicGenesisState(t, 64)
+	b, err := testutil.GenerateFullBlock(genesis, keys, testutil.DefaultBlockGenConfig(), 1)
+	assert.NoError(t, err)
+	beaconDB := testDB.SetupDB(t)
+	genesisBlockRoot := bytesutil.ToBytes32(nil)
+	require.NoError(t, beaconDB.SaveState(ctx, genesis, genesisBlockRoot))
+	cfg := &Config{
+		BeaconDB: beaconDB,
+		ForkChoiceStore: protoarray.New(
+			0, // justifiedEpoch
+			0, // finalizedEpoch
+			genesisBlockRoot,
+		),
+		AttPool:       attestations.NewPool(),
+		ExitPool:      voluntaryexits.NewPool(),
+		StateNotifier: &blockchainTesting.MockStateNotifier{RecordEvents: true},
+		StateGen:      stategen.New(beaconDB),
+	}
+	s, err := NewService(ctx, cfg)
+	require.NoError(t, err)
+	require.NoError(t, s.saveGenesisData(ctx, genesis))
+	gBlk, err := s.cfg.BeaconDB.GenesisBlock(ctx)
+	require.NoError(t, err)
+	gRoot, err := gBlk.Block.HashTreeRoot()
+	require.NoError(t, err)
+	s.finalizedCheckpt = &ethpb.Checkpoint{Root: gRoot[:]}
+	root, err := b.Block.HashTreeRoot()
+	require.NoError(t, err)
+	wg := sync.WaitGroup{}
+	wg.Add(1)
+	go func() {
+		require.NoError(t, s.ReceiveBlock(ctx, b, root))
+		wg.Done()
+	}()
+	wg.Wait()
+	if recvd := len(s.cfg.StateNotifier.(*blockchainTesting.MockStateNotifier).ReceivedEvents()); recvd < 1 {
+		t.Errorf("Received %d state notifications, expected at least 1", recvd)
+	}
+	// Verify fork choice has processed the block. (Genesis block and the new block)
+	assert.Equal(t, 2, len(s.cfg.ForkChoiceStore.Nodes()))
+}
+
+func TestService_ReceiveBlockBatch(t *testing.T) {
+	ctx := context.Background()
+
+	genesis, keys := testutil.DeterministicGenesisState(t, 64)
+	genFullBlock := func(t *testing.T, conf *testutil.BlockGenConfig, slot types.Slot) *ethpb.SignedBeaconBlock {
+		blk, err := testutil.GenerateFullBlock(genesis, keys, conf, slot)
+		assert.NoError(t, err)
+		return blk
+	}
+
+	type args struct {
+		block *ethpb.SignedBeaconBlock
+	}
+	tests := []struct {
+		name      string
+		args      args
+		wantedErr string
+		check     func(*testing.T, *Service)
+	}{
+		{
+			name: "applies block with state transition",
+			args: args{
+				block: genFullBlock(t, testutil.DefaultBlockGenConfig(), 2 /*slot*/),
+			},
+			check: func(t *testing.T, s *Service) {
+				assert.Equal(t, types.Slot(2), s.head.state.Slot(), "Incorrect head state slot")
+				assert.Equal(t, types.Slot(2), s.head.block.Block.Slot, "Incorrect head block slot")
+			},
+		},
+		{
+			name: "notifies block processed on state feed",
+			args: args{
+				block: genFullBlock(t, testutil.DefaultBlockGenConfig(), 1 /*slot*/),
+			},
+			check: func(t *testing.T, s *Service) {
+				if recvd := len(s.cfg.StateNotifier.(*blockchainTesting.MockStateNotifier).ReceivedEvents()); recvd < 1 {
+					t.Errorf("Received %d state notifications, expected at least 1", recvd)
+				}
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			beaconDB := testDB.SetupDB(t)
+			genesisBlockRoot, err := genesis.HashTreeRoot(ctx)
+			require.NoError(t, err)
+			cfg := &Config{
+				BeaconDB: beaconDB,
+				ForkChoiceStore: protoarray.New(
+					0, // justifiedEpoch
+					0, // finalizedEpoch
+					genesisBlockRoot,
+				),
+				StateNotifier: &blockchainTesting.MockStateNotifier{RecordEvents: true},
+				StateGen:      stategen.New(beaconDB),
+			}
+			s, err := NewService(ctx, cfg)
+			require.NoError(t, err)
+			err = s.saveGenesisData(ctx, genesis)
+			require.NoError(t, err)
+			gBlk, err := s.cfg.BeaconDB.GenesisBlock(ctx)
+			require.NoError(t, err)
+
+			gRoot, err := gBlk.Block.HashTreeRoot()
+			require.NoError(t, err)
+			s.finalizedCheckpt = &ethpb.Checkpoint{Root: gRoot[:]}
+			root, err := tt.args.block.Block.HashTreeRoot()
+			require.NoError(t, err)
+			blks := []*ethpb.SignedBeaconBlock{tt.args.block}
+			roots := [][32]byte{root}
+			err = s.ReceiveBlockBatch(ctx, blks, roots)
+			if tt.wantedErr != "" {
+				assert.ErrorContains(t, tt.wantedErr, err)
+			} else {
+				assert.NoError(t, err)
+				tt.check(t, s)
+			}
+		})
+	}
+}
+
+func TestService_HasInitSyncBlock(t *testing.T) {
+	s, err := NewService(context.Background(), &Config{StateNotifier: &blockchainTesting.MockStateNotifier{}})
+	require.NoError(t, err)
+	r := [32]byte{'a'}
+	if s.HasInitSyncBlock(r) {
+		t.Error("Should not have block")
+	}
+	s.saveInitSyncBlock(r, testutil.NewBeaconBlock())
+	if !s.HasInitSyncBlock(r) {
+		t.Error("Should have block")
+	}
+}
+
+func TestCheckSaveHotStateDB_Enabling(t *testing.T) {
+	beaconDB := testDB.SetupDB(t)
+	hook := logTest.NewGlobal()
+	s, err := NewService(context.Background(), &Config{StateGen: stategen.New(beaconDB)})
+	require.NoError(t, err)
+	st := params.BeaconConfig().SlotsPerEpoch.Mul(uint64(epochsSinceFinalitySaveHotStateDB))
+	s.genesisTime = time.Now().Add(time.Duration(-1*int64(st)*int64(params.BeaconConfig().SecondsPerSlot)) * time.Second)
+	s.finalizedCheckpt = &ethpb.Checkpoint{}
+
+	require.NoError(t, s.checkSaveHotStateDB(context.Background()))
+	assert.LogsContain(t, hook, "Entering mode to save hot states in DB")
+}
+
+func TestCheckSaveHotStateDB_Disabling(t *testing.T) {
+	beaconDB := testDB.SetupDB(t)
+	hook := logTest.NewGlobal()
+	s, err := NewService(context.Background(), &Config{StateGen: stategen.New(beaconDB)})
+	require.NoError(t, err)
+	s.finalizedCheckpt = &ethpb.Checkpoint{}
+	require.NoError(t, s.checkSaveHotStateDB(context.Background()))
+	s.genesisTime = time.Now()
+
+	require.NoError(t, s.checkSaveHotStateDB(context.Background()))
+	assert.LogsContain(t, hook, "Exiting mode to save hot states in DB")
+}
+
+func TestCheckSaveHotStateDB_Overflow(t *testing.T) {
+	beaconDB := testDB.SetupDB(t)
+	hook := logTest.NewGlobal()
+	s, err := NewService(context.Background(), &Config{StateGen: stategen.New(beaconDB)})
+	require.NoError(t, err)
+	s.finalizedCheckpt = &ethpb.Checkpoint{Epoch: 10000000}
+	s.genesisTime = time.Now()
+
+	require.NoError(t, s.checkSaveHotStateDB(context.Background()))
+	assert.LogsDoNotContain(t, hook, "Entering mode to save hot states in DB")
+}
--- a/beacon-chain/blockchain/service.go
+++ b/beacon-chain/blockchain/service.go
@@ -11,18 +11,15 @@ import (
 	"time"

 	"github.com/pkg/errors"
+	types "github.com/prysmaticlabs/eth2-types"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/cache"
 	"github.com/prysmaticlabs/prysm/beacon-chain/cache/depositcache"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/epoch/precompute"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/feed"
 	statefeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/db"
-	"github.com/prysmaticlabs/prysm/beacon-chain/db/filters"
-	"github.com/prysmaticlabs/prysm/beacon-chain/flags"
 	f "github.com/prysmaticlabs/prysm/beacon-chain/forkchoice"
 	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
 	"github.com/prysmaticlabs/prysm/beacon-chain/operations/attestations"
@@ -30,75 +27,62 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/operations/voluntaryexits"
 	"github.com/prysmaticlabs/prysm/beacon-chain/p2p"
 	"github.com/prysmaticlabs/prysm/beacon-chain/powchain"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateV0"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateutil"
-	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
+	"github.com/prysmaticlabs/prysm/cmd/beacon-chain/flags"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
-	"github.com/prysmaticlabs/prysm/shared/featureconfig"
 	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/prysmaticlabs/prysm/shared/slotutil"
+	"github.com/sirupsen/logrus"
 	"go.opencensus.io/trace"
 )

+// headSyncMinEpochsAfterCheckpoint defines how many epochs should elapse after known finalization
+// checkpoint for head sync to be triggered.
+const headSyncMinEpochsAfterCheckpoint = 128
+
 // Service represents a service that handles the internal
 // logic of managing the full PoS beacon chain.
 type Service struct {
-	ctx                       context.Context
-	cancel                    context.CancelFunc
-	beaconDB                  db.HeadAccessDatabase
-	depositCache              *depositcache.DepositCache
-	chainStartFetcher         powchain.ChainStartFetcher
-	attPool                   attestations.Pool
-	slashingPool              *slashings.Pool
-	exitPool                  *voluntaryexits.Pool
-	genesisTime               time.Time
-	p2p                       p2p.Broadcaster
-	maxRoutines               int64
-	head                      *head
-	headLock                  sync.RWMutex
-	stateNotifier             statefeed.Notifier
-	genesisRoot               [32]byte
-	epochParticipation        map[uint64]*precompute.Balance
-	epochParticipationLock    sync.RWMutex
-	forkChoiceStore           f.ForkChoicer
-	justifiedCheckpt          *ethpb.Checkpoint
-	prevJustifiedCheckpt      *ethpb.Checkpoint
-	bestJustifiedCheckpt      *ethpb.Checkpoint
-	finalizedCheckpt          *ethpb.Checkpoint
-	prevFinalizedCheckpt      *ethpb.Checkpoint
-	nextEpochBoundarySlot     uint64
-	voteLock                  sync.RWMutex
-	initSyncState             map[[32]byte]*stateTrie.BeaconState
-	boundaryRoots             [][32]byte
-	initSyncStateLock         sync.RWMutex
-	checkpointState           *cache.CheckpointStateCache
-	checkpointStateLock       sync.Mutex
-	stateGen                  *stategen.State
-	opsService                *attestations.Service
-	initSyncBlocks            map[[32]byte]*ethpb.SignedBeaconBlock
-	initSyncBlocksLock        sync.RWMutex
-	recentCanonicalBlocks     map[[32]byte]bool
-	recentCanonicalBlocksLock sync.RWMutex
-	justifiedBalances         []uint64
-	justifiedBalancesLock     sync.RWMutex
+	cfg                   *Config
+	ctx                   context.Context
+	cancel                context.CancelFunc
+	genesisTime           time.Time
+	head                  *head
+	headLock              sync.RWMutex
+	genesisRoot           [32]byte
+	justifiedCheckpt      *ethpb.Checkpoint
+	prevJustifiedCheckpt  *ethpb.Checkpoint
+	bestJustifiedCheckpt  *ethpb.Checkpoint
+	finalizedCheckpt      *ethpb.Checkpoint
+	prevFinalizedCheckpt  *ethpb.Checkpoint
+	nextEpochBoundarySlot types.Slot
+	boundaryRoots         [][32]byte
+	checkpointStateCache  *cache.CheckpointStateCache
+	initSyncBlocks        map[[32]byte]*ethpb.SignedBeaconBlock
+	initSyncBlocksLock    sync.RWMutex
+	justifiedBalances     []uint64
+	justifiedBalancesLock sync.RWMutex
+	wsVerified            bool
 }

 // Config options for the service.
 type Config struct {
-	BeaconBlockBuf    int
-	ChainStartFetcher powchain.ChainStartFetcher
-	BeaconDB          db.HeadAccessDatabase
-	DepositCache      *depositcache.DepositCache
-	AttPool           attestations.Pool
-	ExitPool          *voluntaryexits.Pool
-	SlashingPool      *slashings.Pool
-	P2p               p2p.Broadcaster
-	MaxRoutines       int64
-	StateNotifier     statefeed.Notifier
-	ForkChoiceStore   f.ForkChoicer
-	OpsService        *attestations.Service
-	StateGen          *stategen.State
+	BeaconBlockBuf          int
+	ChainStartFetcher       powchain.ChainStartFetcher
+	BeaconDB                db.HeadAccessDatabase
+	DepositCache            *depositcache.DepositCache
+	AttPool                 attestations.Pool
+	ExitPool                voluntaryexits.PoolManager
+	SlashingPool            slashings.PoolManager
+	P2p                     p2p.Broadcaster
+	MaxRoutines             int
+	StateNotifier           statefeed.Notifier
+	ForkChoiceStore         f.ForkChoicer
+	OpsService              *attestations.Service
+	StateGen                *stategen.State
+	WeakSubjectivityCheckpt *ethpb.Checkpoint
 }

 // NewService instantiates a new block service instance that will
@@ -106,51 +90,45 @@ type Config struct {
 func NewService(ctx context.Context, cfg *Config) (*Service, error) {
 	ctx, cancel := context.WithCancel(ctx)
 	return &Service{
-		ctx:                   ctx,
-		cancel:                cancel,
-		beaconDB:              cfg.BeaconDB,
-		depositCache:          cfg.DepositCache,
-		chainStartFetcher:     cfg.ChainStartFetcher,
-		attPool:               cfg.AttPool,
-		exitPool:              cfg.ExitPool,
-		slashingPool:          cfg.SlashingPool,
-		p2p:                   cfg.P2p,
-		maxRoutines:           cfg.MaxRoutines,
-		stateNotifier:         cfg.StateNotifier,
-		epochParticipation:    make(map[uint64]*precompute.Balance),
-		forkChoiceStore:       cfg.ForkChoiceStore,
-		initSyncState:         make(map[[32]byte]*stateTrie.BeaconState),
-		boundaryRoots:         [][32]byte{},
-		checkpointState:       cache.NewCheckpointStateCache(),
-		opsService:            cfg.OpsService,
-		stateGen:              cfg.StateGen,
-		initSyncBlocks:        make(map[[32]byte]*ethpb.SignedBeaconBlock),
-		recentCanonicalBlocks: make(map[[32]byte]bool),
-		justifiedBalances:     make([]uint64, 0),
+		cfg:                  cfg,
+		ctx:                  ctx,
+		cancel:               cancel,
+		boundaryRoots:        [][32]byte{},
+		checkpointStateCache: cache.NewCheckpointStateCache(),
+		initSyncBlocks:       make(map[[32]byte]*ethpb.SignedBeaconBlock),
+		justifiedBalances:    make([]uint64, 0),
 	}, nil
 }

 // Start a blockchain service's main event loop.
 func (s *Service) Start() {
-	ctx := context.TODO()
-	beaconState, err := s.beaconDB.HeadState(ctx)
-	if err != nil {
-		log.Fatalf("Could not fetch beacon state: %v", err)
-	}
-
 	// For running initial sync with state cache, in an event of restart, we use
 	// last finalized check point as start point to sync instead of head
 	// state. This is because we no longer save state every slot during sync.
-	cp, err := s.beaconDB.FinalizedCheckpoint(ctx)
+	cp, err := s.cfg.BeaconDB.FinalizedCheckpoint(s.ctx)
 	if err != nil {
 		log.Fatalf("Could not fetch finalized cp: %v", err)
 	}

-	if beaconState == nil {
-		beaconState, err = s.stateGen.StateByRoot(ctx, bytesutil.ToBytes32(cp.Root))
+	r := bytesutil.ToBytes32(cp.Root)
+	// Before the first finalized epoch, in the current epoch,
+	// the finalized root is defined as zero hashes instead of genesis root hash.
+	// We want to use genesis root to retrieve for state.
+	if r == params.BeaconConfig().ZeroHash {
+		genesisBlock, err := s.cfg.BeaconDB.GenesisBlock(s.ctx)
 		if err != nil {
-			log.Fatalf("Could not fetch beacon state by root: %v", err)
+			log.Fatalf("Could not fetch finalized cp: %v", err)
 		}
+		if genesisBlock != nil {
+			r, err = genesisBlock.Block.HashTreeRoot()
+			if err != nil {
+				log.Fatalf("Could not tree hash genesis block: %v", err)
+			}
+		}
+	}
+	beaconState, err := s.cfg.StateGen.StateByRoot(s.ctx, r)
+	if err != nil {
+		log.Fatalf("Could not fetch beacon state by root: %v", err)
 	}

 	// Make sure that attestation processor is subscribed and ready for state initializing event.
@@ -160,35 +138,63 @@ func (s *Service) Start() {
 	if beaconState != nil {
 		log.Info("Blockchain data already exists in DB, initializing...")
 		s.genesisTime = time.Unix(int64(beaconState.GenesisTime()), 0)
-		s.opsService.SetGenesisTime(beaconState.GenesisTime())
-		if err := s.initializeChainInfo(ctx); err != nil {
+		s.cfg.OpsService.SetGenesisTime(beaconState.GenesisTime())
+		if err := s.initializeChainInfo(s.ctx); err != nil {
 			log.Fatalf("Could not set up chain info: %v", err)
 		}

 		// We start a counter to genesis, if needed.
-		go slotutil.CountdownToGenesis(ctx, s.genesisTime, uint64(beaconState.NumValidators()))
+		gState, err := s.cfg.BeaconDB.GenesisState(s.ctx)
+		if err != nil {
+			log.Fatalf("Could not retrieve genesis state: %v", err)
+		}
+		gRoot, err := gState.HashTreeRoot(s.ctx)
+		if err != nil {
+			log.Fatalf("Could not hash tree root genesis state: %v", err)
+		}
+		go slotutil.CountdownToGenesis(s.ctx, s.genesisTime, uint64(gState.NumValidators()), gRoot)

-		justifiedCheckpoint, err := s.beaconDB.JustifiedCheckpoint(ctx)
+		justifiedCheckpoint, err := s.cfg.BeaconDB.JustifiedCheckpoint(s.ctx)
 		if err != nil {
 			log.Fatalf("Could not get justified checkpoint: %v", err)
 		}
-		finalizedCheckpoint, err := s.beaconDB.FinalizedCheckpoint(ctx)
+		finalizedCheckpoint, err := s.cfg.BeaconDB.FinalizedCheckpoint(s.ctx)
 		if err != nil {
 			log.Fatalf("Could not get finalized checkpoint: %v", err)
 		}

 		// Resume fork choice.
-		s.justifiedCheckpt = stateTrie.CopyCheckpoint(justifiedCheckpoint)
-		if err := s.cacheJustifiedStateBalances(ctx, bytesutil.ToBytes32(s.justifiedCheckpt.Root)); err != nil {
+		s.justifiedCheckpt = stateV0.CopyCheckpoint(justifiedCheckpoint)
+		if err := s.cacheJustifiedStateBalances(s.ctx, s.ensureRootNotZeros(bytesutil.ToBytes32(s.justifiedCheckpt.Root))); err != nil {
 			log.Fatalf("Could not cache justified state balances: %v", err)
 		}
-		s.prevJustifiedCheckpt = stateTrie.CopyCheckpoint(justifiedCheckpoint)
-		s.bestJustifiedCheckpt = stateTrie.CopyCheckpoint(justifiedCheckpoint)
-		s.finalizedCheckpt = stateTrie.CopyCheckpoint(finalizedCheckpoint)
-		s.prevFinalizedCheckpt = stateTrie.CopyCheckpoint(finalizedCheckpoint)
+		s.prevJustifiedCheckpt = stateV0.CopyCheckpoint(justifiedCheckpoint)
+		s.bestJustifiedCheckpt = stateV0.CopyCheckpoint(justifiedCheckpoint)
+		s.finalizedCheckpt = stateV0.CopyCheckpoint(finalizedCheckpoint)
+		s.prevFinalizedCheckpt = stateV0.CopyCheckpoint(finalizedCheckpoint)
 		s.resumeForkChoice(justifiedCheckpoint, finalizedCheckpoint)

-		s.stateNotifier.StateFeed().Send(&feed.Event{
+		ss, err := helpers.StartSlot(s.finalizedCheckpt.Epoch)
+		if err != nil {
+			log.Fatalf("Could not get start slot of finalized epoch: %v", err)
+		}
+		h := s.headBlock().Block
+		if h.Slot > ss {
+			log.WithFields(logrus.Fields{
+				"startSlot": ss,
+				"endSlot":   h.Slot,
+			}).Info("Loading blocks to fork choice store, this may take a while.")
+			if err := s.fillInForkChoiceMissingBlocks(s.ctx, h, s.finalizedCheckpt, s.justifiedCheckpt); err != nil {
+				log.Fatalf("Could not fill in fork choice store missing blocks: %v", err)
+			}
+		}
+
+		if err := s.VerifyWeakSubjectivityRoot(s.ctx); err != nil {
+			// Exit run time if the node failed to verify weak subjectivity checkpoint.
+			log.Fatalf("Could not verify weak subjectivity checkpoint: %v", err)
+		}
+
+		s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
 			Type: statefeed.Initialized,
 			Data: &statefeed.InitializedData{
 				StartTime:             s.genesisTime,
@@ -197,13 +203,13 @@ func (s *Service) Start() {
 		})
 	} else {
 		log.Info("Waiting to reach the validator deposit threshold to start the beacon chain...")
-		if s.chainStartFetcher == nil {
+		if s.cfg.ChainStartFetcher == nil {
 			log.Fatal("Not configured web3Service for POW chain")
 			return // return need for TestStartUninitializedChainWithoutConfigPOWChain.
 		}
 		go func() {
 			stateChannel := make(chan *feed.Event, 1)
-			stateSub := s.stateNotifier.StateFeed().Subscribe(stateChannel)
+			stateSub := s.cfg.StateNotifier.StateFeed().Subscribe(stateChannel)
 			defer stateSub.Unsubscribe()
 			<-attestationProcessorSubscribed
 			for {
@@ -216,7 +222,7 @@ func (s *Service) Start() {
 							return
 						}
 						log.WithField("starttime", data.StartTime).Debug("Received chain start event")
-						s.processChainStartTime(ctx, data.StartTime)
+						s.processChainStartTime(s.ctx, data.StartTime)
 						return
 					}
 				case <-s.ctx.Done():
@@ -230,23 +236,27 @@ func (s *Service) Start() {
 		}()
 	}

-	go s.processAttestation(attestationProcessorSubscribed)
+	go s.processAttestationsRoutine(attestationProcessorSubscribed)
 }

 // processChainStartTime initializes a series of deposits from the ChainStart deposits in the eth1
 // deposit contract, initializes the beacon chain's state, and kicks off the beacon chain.
 func (s *Service) processChainStartTime(ctx context.Context, genesisTime time.Time) {
-	preGenesisState := s.chainStartFetcher.PreGenesisState()
-	initializedState, err := s.initializeBeaconChain(ctx, genesisTime, preGenesisState, s.chainStartFetcher.ChainStartEth1Data())
+	preGenesisState := s.cfg.ChainStartFetcher.PreGenesisState()
+	initializedState, err := s.initializeBeaconChain(ctx, genesisTime, preGenesisState, s.cfg.ChainStartFetcher.ChainStartEth1Data())
 	if err != nil {
 		log.Fatalf("Could not initialize beacon chain: %v", err)
 	}
 	// We start a counter to genesis, if needed.
-	go slotutil.CountdownToGenesis(ctx, genesisTime, uint64(initializedState.NumValidators()))
+	gRoot, err := initializedState.HashTreeRoot(s.ctx)
+	if err != nil {
+		log.Fatalf("Could not hash tree root genesis state: %v", err)
+	}
+	go slotutil.CountdownToGenesis(ctx, genesisTime, uint64(initializedState.NumValidators()), gRoot)

 	// We send out a state initialized event to the rest of the services
 	// running in the beacon node.
-	s.stateNotifier.StateFeed().Send(&feed.Event{
+	s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
 		Type: statefeed.Initialized,
 		Data: &statefeed.InitializedData{
 			StartTime:             genesisTime,
@@ -261,9 +271,9 @@ func (s *Service) processChainStartTime(ctx context.Context, genesisTime time.Ti
 func (s *Service) initializeBeaconChain(
 	ctx context.Context,
 	genesisTime time.Time,
-	preGenesisState *stateTrie.BeaconState,
-	eth1data *ethpb.Eth1Data) (*stateTrie.BeaconState, error) {
-	_, span := trace.StartSpan(context.Background(), "beacon-chain.Service.initializeBeaconChain")
+	preGenesisState iface.BeaconState,
+	eth1data *ethpb.Eth1Data) (iface.BeaconState, error) {
+	ctx, span := trace.StartSpan(ctx, "beacon-chain.Service.initializeBeaconChain")
 	defer span.End()
 	s.genesisTime = genesisTime
 	unixTime := uint64(genesisTime.Unix())
@@ -280,17 +290,17 @@ func (s *Service) initializeBeaconChain(
 	log.Info("Initialized beacon chain genesis state")

 	// Clear out all pre-genesis data now that the state is initialized.
-	s.chainStartFetcher.ClearPreGenesisData()
+	s.cfg.ChainStartFetcher.ClearPreGenesisData()

 	// Update committee shuffled indices for genesis epoch.
 	if err := helpers.UpdateCommitteeCache(genesisState, 0 /* genesis epoch */); err != nil {
 		return nil, err
 	}
-	if err := helpers.UpdateProposerIndicesInCache(genesisState, 0 /* genesis epoch */); err != nil {
+	if err := helpers.UpdateProposerIndicesInCache(genesisState); err != nil {
 		return nil, err
 	}

-	s.opsService.SetGenesisTime(genesisState.GenesisTime())
+	s.cfg.OpsService.SetGenesisTime(genesisState.GenesisTime())

 	return genesisState, nil
 }
@@ -298,70 +308,59 @@ func (s *Service) initializeBeaconChain(
 // Stop the blockchain service's main event loop and associated goroutines.
 func (s *Service) Stop() error {
 	defer s.cancel()
-	return nil
+
+	if s.cfg.StateGen != nil && s.head != nil && s.head.state != nil {
+		if err := s.cfg.StateGen.ForceCheckpoint(s.ctx, s.head.state.FinalizedCheckpoint().Root); err != nil {
+			return err
+		}
+	}
+
+	// Save initial sync cached blocks to the DB before stop.
+	return s.cfg.BeaconDB.SaveBlocks(s.ctx, s.getInitSyncBlocks())
 }

 // Status always returns nil unless there is an error condition that causes
 // this service to be unhealthy.
 func (s *Service) Status() error {
-	if int64(runtime.NumGoroutine()) > s.maxRoutines {
+	if s.genesisRoot == params.BeaconConfig().ZeroHash {
+		return errors.New("genesis state has not been created")
+	}
+	if runtime.NumGoroutine() > s.cfg.MaxRoutines {
 		return fmt.Errorf("too many goroutines %d", runtime.NumGoroutine())
 	}
 	return nil
 }

-// ClearCachedStates removes all stored caches states. This is done after the node
-// is synced.
-func (s *Service) ClearCachedStates() {
-	s.initSyncState = map[[32]byte]*stateTrie.BeaconState{}
-}
-
 // This gets called when beacon chain is first initialized to save genesis data (state, block, and more) in db.
-func (s *Service) saveGenesisData(ctx context.Context, genesisState *stateTrie.BeaconState) error {
-	stateRoot, err := genesisState.HashTreeRoot(ctx)
-	if err != nil {
-		return err
+func (s *Service) saveGenesisData(ctx context.Context, genesisState iface.BeaconState) error {
+	if err := s.cfg.BeaconDB.SaveGenesisData(ctx, genesisState); err != nil {
+		return errors.Wrap(err, "could not save genesis data")
 	}
-	genesisBlk := blocks.NewGenesisBlock(stateRoot[:])
-	genesisBlkRoot, err := stateutil.BlockRoot(genesisBlk.Block)
+	genesisBlk, err := s.cfg.BeaconDB.GenesisBlock(ctx)
+	if err != nil || genesisBlk == nil {
+		return fmt.Errorf("could not load genesis block: %v", err)
+	}
+	genesisBlkRoot, err := genesisBlk.Block.HashTreeRoot()
 	if err != nil {
 		return errors.Wrap(err, "could not get genesis block root")
 	}
+
 	s.genesisRoot = genesisBlkRoot
-
-	if err := s.beaconDB.SaveBlock(ctx, genesisBlk); err != nil {
-		return errors.Wrap(err, "could not save genesis block")
-	}
-	if err := s.stateGen.SaveState(ctx, genesisBlkRoot, genesisState); err != nil {
-		return errors.Wrap(err, "could not save genesis state")
-	}
-	if err := s.beaconDB.SaveStateSummary(ctx, &pb.StateSummary{
-		Slot: 0,
-		Root: genesisBlkRoot[:],
-	}); err != nil {
-		return err
-	}
-
-	if err := s.beaconDB.SaveHeadBlockRoot(ctx, genesisBlkRoot); err != nil {
-		return errors.Wrap(err, "could not save head block root")
-	}
-	if err := s.beaconDB.SaveGenesisBlockRoot(ctx, genesisBlkRoot); err != nil {
-		return errors.Wrap(err, "could not save genesis block root")
-	}
+	s.cfg.StateGen.SaveFinalizedState(0 /*slot*/, genesisBlkRoot, genesisState)

 	// Finalized checkpoint at genesis is a zero hash.
 	genesisCheckpoint := genesisState.FinalizedCheckpoint()

-	s.justifiedCheckpt = stateTrie.CopyCheckpoint(genesisCheckpoint)
+	s.justifiedCheckpt = stateV0.CopyCheckpoint(genesisCheckpoint)
 	if err := s.cacheJustifiedStateBalances(ctx, genesisBlkRoot); err != nil {
 		return err
 	}
-	s.prevJustifiedCheckpt = stateTrie.CopyCheckpoint(genesisCheckpoint)
-	s.bestJustifiedCheckpt = stateTrie.CopyCheckpoint(genesisCheckpoint)
-	s.finalizedCheckpt = stateTrie.CopyCheckpoint(genesisCheckpoint)
-	s.prevFinalizedCheckpt = stateTrie.CopyCheckpoint(genesisCheckpoint)
+	s.prevJustifiedCheckpt = stateV0.CopyCheckpoint(genesisCheckpoint)
+	s.bestJustifiedCheckpt = stateV0.CopyCheckpoint(genesisCheckpoint)
+	s.finalizedCheckpt = stateV0.CopyCheckpoint(genesisCheckpoint)
+	s.prevFinalizedCheckpt = stateV0.CopyCheckpoint(genesisCheckpoint)

-	if err := s.forkChoiceStore.ProcessBlock(ctx,
+	if err := s.cfg.ForkChoiceStore.ProcessBlock(ctx,
 		genesisBlk.Block.Slot,
 		genesisBlkRoot,
 		params.BeaconConfig().ZeroHash,
@@ -372,43 +371,25 @@ func (s *Service) saveGenesisData(ctx context.Context, genesisState *stateTrie.B
 	}

 	s.setHead(genesisBlkRoot, genesisBlk, genesisState)
-
 	return nil
 }

 // This gets called to initialize chain info variables using the finalized checkpoint stored in DB
 func (s *Service) initializeChainInfo(ctx context.Context) error {
-	genesisBlock, err := s.beaconDB.GenesisBlock(ctx)
+	genesisBlock, err := s.cfg.BeaconDB.GenesisBlock(ctx)
 	if err != nil {
 		return errors.Wrap(err, "could not get genesis block from db")
 	}
 	if genesisBlock == nil {
 		return errors.New("no genesis block in db")
 	}
-	genesisBlkRoot, err := stateutil.BlockRoot(genesisBlock.Block)
+	genesisBlkRoot, err := genesisBlock.Block.HashTreeRoot()
 	if err != nil {
 		return errors.Wrap(err, "could not get signing root of genesis block")
 	}
 	s.genesisRoot = genesisBlkRoot

-	if flags.Get().UnsafeSync {
-		headBlock, err := s.beaconDB.HeadBlock(ctx)
-		if err != nil {
-			return errors.Wrap(err, "could not retrieve head block")
-		}
-		headRoot, err := stateutil.BlockRoot(headBlock.Block)
-		if err != nil {
-			return errors.Wrap(err, "could not hash head block")
-		}
-		headState, err := s.beaconDB.HeadState(ctx)
-		if err != nil {
-			return errors.Wrap(err, "could not retrieve head state")
-		}
-		s.setHead(headRoot, headBlock, headState)
-		return nil
-	}
-
-	finalized, err := s.beaconDB.FinalizedCheckpoint(ctx)
+	finalized, err := s.cfg.BeaconDB.FinalizedCheckpoint(ctx)
 	if err != nil {
 		return errors.Wrap(err, "could not get finalized checkpoint from db")
 	}
@@ -417,40 +398,55 @@ func (s *Service) initializeChainInfo(ctx context.Context) error {
 		// would be the genesis state and block.
 		return errors.New("no finalized epoch in the database")
 	}
-	finalizedRoot := bytesutil.ToBytes32(finalized.Root)
-	var finalizedState *stateTrie.BeaconState
+	finalizedRoot := s.ensureRootNotZeros(bytesutil.ToBytes32(finalized.Root))
+	var finalizedState iface.BeaconState

-	finalizedState, err = s.stateGen.Resume(ctx)
+	finalizedState, err = s.cfg.StateGen.Resume(ctx)
 	if err != nil {
 		return errors.Wrap(err, "could not get finalized state from db")
 	}
-	if !featureconfig.Get().SkipRegenHistoricalStates {
-		// Since historical states were skipped, the node should start from last finalized check point.
-		finalizedRoot = s.beaconDB.LastArchivedIndexRoot(ctx)
-		if finalizedRoot == params.BeaconConfig().ZeroHash {
-			finalizedRoot = bytesutil.ToBytes32(finalized.Root)
+
+	if flags.Get().HeadSync {
+		headBlock, err := s.cfg.BeaconDB.HeadBlock(ctx)
+		if err != nil {
+			return errors.Wrap(err, "could not retrieve head block")
+		}
+		headEpoch := helpers.SlotToEpoch(headBlock.Block.Slot)
+		var epochsSinceFinality types.Epoch
+		if headEpoch > finalized.Epoch {
+			epochsSinceFinality = headEpoch - finalized.Epoch
+		}
+		// Head sync when node is far enough beyond known finalized epoch,
+		// this becomes really useful during long period of non-finality.
+		if epochsSinceFinality >= headSyncMinEpochsAfterCheckpoint {
+			headRoot, err := headBlock.Block.HashTreeRoot()
+			if err != nil {
+				return errors.Wrap(err, "could not hash head block")
+			}
+			finalizedState, err := s.cfg.StateGen.Resume(ctx)
+			if err != nil {
+				return errors.Wrap(err, "could not get finalized state from db")
+			}
+			log.Infof("Regenerating state from the last checkpoint at slot %d to current head slot of %d."+
+				"This process may take a while, please wait.", finalizedState.Slot(), headBlock.Block.Slot)
+			headState, err := s.cfg.StateGen.StateByRoot(ctx, headRoot)
+			if err != nil {
+				return errors.Wrap(err, "could not retrieve head state")
+			}
+			s.setHead(headRoot, headBlock, headState)
+			return nil
+		} else {
+			log.Warnf("Finalized checkpoint at slot %d is too close to the current head slot, "+
+				"resetting head from the checkpoint ('--%s' flag is ignored).",
+				finalizedState.Slot(), flags.HeadSync.Name)
 		}
 	}

-	finalizedBlock, err := s.beaconDB.Block(ctx, finalizedRoot)
+	finalizedBlock, err := s.cfg.BeaconDB.Block(ctx, finalizedRoot)
 	if err != nil {
 		return errors.Wrap(err, "could not get finalized block from db")
 	}

-	// To skip the regeneration of historical state, the node has to generate the parent of the last finalized state.
-	// We don't need to do this for genesis.
-	atGenesis := s.CurrentSlot() == 0
-	if featureconfig.Get().SkipRegenHistoricalStates && !atGenesis {
-		parentRoot := bytesutil.ToBytes32(finalizedBlock.Block.ParentRoot)
-		parentState, err := s.generateState(ctx, finalizedRoot, parentRoot)
-		if err != nil {
-			return err
-		}
-		if s.beaconDB.SaveState(ctx, parentState, parentRoot) != nil {
-			return err
-		}
-	}
-
 	if finalizedState == nil || finalizedBlock == nil {
 		return errors.New("finalized state and block can't be nil")
 	}
@@ -459,34 +455,11 @@ func (s *Service) initializeChainInfo(ctx context.Context) error {
 	return nil
 }

-// This is called when a client starts from a non-genesis slot. It deletes the states in DB
-// from slot 1 (avoid genesis state) to `slot`.
-func (s *Service) pruneGarbageState(ctx context.Context, slot uint64) error {
-	if featureconfig.Get().DontPruneStateStartUp {
-		return nil
-	}
-
-	filter := filters.NewFilter().SetStartSlot(1).SetEndSlot(slot)
-	roots, err := s.beaconDB.BlockRoots(ctx, filter)
-	if err != nil {
-		return err
-	}
-	if err := s.beaconDB.DeleteStates(ctx, roots); err != nil {
-		return err
-	}
-
-	if err := s.beaconDB.SaveLastArchivedIndex(ctx, 0); err != nil {
-		return err
-	}
-
-	return nil
-}
-
 // This is called when a client starts from non-genesis slot. This passes last justified and finalized
 // information to fork choice service to initializes fork choice store.
-func (s *Service) resumeForkChoice(justifiedCheckpoint *ethpb.Checkpoint, finalizedCheckpoint *ethpb.Checkpoint) {
+func (s *Service) resumeForkChoice(justifiedCheckpoint, finalizedCheckpoint *ethpb.Checkpoint) {
 	store := protoarray.New(justifiedCheckpoint.Epoch, finalizedCheckpoint.Epoch, bytesutil.ToBytes32(finalizedCheckpoint.Root))
-	s.forkChoiceStore = store
+	s.cfg.ForkChoiceStore = store
 }

 // This returns true if block has been processed before. Two ways to verify the block has been processed:
@@ -494,9 +467,9 @@ func (s *Service) resumeForkChoice(justifiedCheckpoint *ethpb.Checkpoint, finali
 // 2.) Check DB.
 // Checking 1.) is ten times faster than checking 2.)
 func (s *Service) hasBlock(ctx context.Context, root [32]byte) bool {
-	if s.forkChoiceStore.HasNode(root) {
+	if s.cfg.ForkChoiceStore.HasNode(root) {
 		return true
 	}

-	return s.beaconDB.HasBlock(ctx, root)
+	return s.cfg.BeaconDB.HasBlock(ctx, root)
 }
--- a/beacon-chain/blockchain/service_norace_test.go
+++ b/beacon-chain/blockchain/service_norace_test.go
@@ -6,6 +6,7 @@ import (
 	"testing"

 	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 	"github.com/sirupsen/logrus"
 )

@@ -15,16 +16,12 @@ func init() {
 }

 func TestChainService_SaveHead_DataRace(t *testing.T) {
-	db, _ := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)
 	s := &Service{
-		beaconDB: db,
+		cfg: &Config{BeaconDB: beaconDB},
 	}
 	go func() {
-		if err := s.saveHead(context.Background(), [32]byte{}); err != nil {
-			t.Fatal(err)
-		}
+		require.NoError(t, s.saveHead(context.Background(), [32]byte{}))
 	}()
-	if err := s.saveHead(context.Background(), [32]byte{}); err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, s.saveHead(context.Background(), [32]byte{}))
 }
--- a/beacon-chain/blockchain/service_test.go
+++ b/beacon-chain/blockchain/service_test.go
@@ -3,7 +3,6 @@ package blockchain
 import (
 	"bytes"
 	"context"
-	"io/ioutil"
 	"reflect"
 	"testing"
 	"time"
@@ -11,8 +10,6 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/gogo/protobuf/proto"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
-	"github.com/prysmaticlabs/go-ssz"
-	"github.com/prysmaticlabs/prysm/beacon-chain/cache"
 	"github.com/prysmaticlabs/prysm/beacon-chain/cache/depositcache"
 	b "github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/feed"
@@ -20,30 +17,25 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/db"
-	"github.com/prysmaticlabs/prysm/beacon-chain/db/filters"
 	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
 	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
 	"github.com/prysmaticlabs/prysm/beacon-chain/operations/attestations"
 	"github.com/prysmaticlabs/prysm/beacon-chain/p2p"
 	"github.com/prysmaticlabs/prysm/beacon-chain/powchain"
-	beaconstate "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateV0"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateutil"
+	"github.com/prysmaticlabs/prysm/cmd/beacon-chain/flags"
 	protodb "github.com/prysmaticlabs/prysm/proto/beacon/db"
 	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/event"
 	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/prysmaticlabs/prysm/shared/testutil"
-	"github.com/sirupsen/logrus"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 	logTest "github.com/sirupsen/logrus/hooks/test"
 )

-func init() {
-	logrus.SetLevel(logrus.DebugLevel)
-	logrus.SetOutput(ioutil.Discard)
-}
-
 type mockBeaconNode struct {
 	stateFeed *event.Feed
 }
@@ -70,16 +62,18 @@ func (mb *mockBroadcaster) BroadcastAttestation(_ context.Context, _ uint64, _ *
 	return nil
 }

-var _ = p2p.Broadcaster(&mockBroadcaster{})
+var _ p2p.Broadcaster = (*mockBroadcaster)(nil)

-func setupBeaconChain(t *testing.T, beaconDB db.Database, sc *cache.StateSummaryCache) *Service {
+func setupBeaconChain(t *testing.T, beaconDB db.Database) *Service {
 	endpoint := "http://127.0.0.1"
 	ctx := context.Background()
 	var web3Service *powchain.Service
 	var err error
 	bState, _ := testutil.DeterministicGenesisState(t, 10)
+	pbState, err := stateV0.ProtobufBeaconState(bState.InnerStateUnsafe())
+	require.NoError(t, err)
 	err = beaconDB.SavePowchainData(ctx, &protodb.ETH1ChainData{
-		BeaconState: bState.InnerStateUnsafe(),
+		BeaconState: pbState,
 		Trie:        &protodb.SparseMerkleTrie{},
 		CurrentEth1Data: &protodb.LatestETH1Data{
 			BlockHash: make([]byte, 32),
@@ -93,435 +87,431 @@ func setupBeaconChain(t *testing.T, beaconDB db.Database, sc *cache.StateSummary
 		},
 		DepositContainers: []*protodb.DepositContainer{},
 	})
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 	web3Service, err = powchain.NewService(ctx, &powchain.Web3ServiceConfig{
 		BeaconDB:        beaconDB,
-		HTTPEndPoint:    endpoint,
+		HttpEndpoints:   []string{endpoint},
 		DepositContract: common.Address{},
 	})
-	if err != nil {
-		t.Fatalf("unable to set up web3 service: %v", err)
-	}
+	require.NoError(t, err, "Unable to set up web3 service")

 	opsService, err := attestations.NewService(ctx, &attestations.Config{Pool: attestations.NewPool()})
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
+
+	depositCache, err := depositcache.New()
+	require.NoError(t, err)
+
 	cfg := &Config{
 		BeaconBlockBuf:    0,
 		BeaconDB:          beaconDB,
-		DepositCache:      depositcache.NewDepositCache(),
+		DepositCache:      depositCache,
 		ChainStartFetcher: web3Service,
 		P2p:               &mockBroadcaster{},
 		StateNotifier:     &mockBeaconNode{},
 		AttPool:           attestations.NewPool(),
-		StateGen:          stategen.New(beaconDB, sc),
+		StateGen:          stategen.New(beaconDB),
 		ForkChoiceStore:   protoarray.New(0, 0, params.BeaconConfig().ZeroHash),
 		OpsService:        opsService,
 	}

+	// Safe a state in stategen to purposes of testing a service stop / shutdown.
+	require.NoError(t, cfg.StateGen.SaveState(ctx, bytesutil.ToBytes32(bState.FinalizedCheckpoint().Root), bState))
+
 	chainService, err := NewService(ctx, cfg)
-	if err != nil {
-		t.Fatalf("unable to setup chain service: %v", err)
-	}
+	require.NoError(t, err, "Unable to setup chain service")
 	chainService.genesisTime = time.Unix(1, 0) // non-zero time

 	return chainService
 }

-func TestChainStartStop_Uninitialized(t *testing.T) {
-	hook := logTest.NewGlobal()
-	db, sc := testDB.SetupDB(t)
-	chainService := setupBeaconChain(t, db, sc)
-
-	// Listen for state events.
-	stateSubChannel := make(chan *feed.Event, 1)
-	stateSub := chainService.stateNotifier.StateFeed().Subscribe(stateSubChannel)
-
-	// Test the chain start state notifier.
-	genesisTime := time.Unix(1, 0)
-	chainService.Start()
-	event := &feed.Event{
-		Type: statefeed.ChainStarted,
-		Data: &statefeed.ChainStartedData{
-			StartTime: genesisTime,
-		},
-	}
-	// Send in a loop to ensure it is delivered (busy wait for the service to subscribe to the state feed).
-	for sent := 1; sent == 1; {
-		sent = chainService.stateNotifier.StateFeed().Send(event)
-		if sent == 1 {
-			// Flush our local subscriber.
-			<-stateSubChannel
-		}
-	}
-
-	// Now wait for notification the state is ready.
-	for stateInitialized := false; stateInitialized == false; {
-		recv := <-stateSubChannel
-		if recv.Type == statefeed.Initialized {
-			stateInitialized = true
-		}
-	}
-	stateSub.Unsubscribe()
-
-	beaconState, err := db.HeadState(context.Background())
-	if err != nil {
-		t.Fatal(err)
-	}
-	if beaconState == nil || beaconState.Slot() != 0 {
-		t.Error("Expected canonical state feed to send a state with genesis block")
-	}
-	if err := chainService.Stop(); err != nil {
-		t.Fatalf("Unable to stop chain service: %v", err)
-	}
-	// The context should have been canceled.
-	if chainService.ctx.Err() != context.Canceled {
-		t.Error("Context was not canceled")
-	}
-	testutil.AssertLogsContain(t, hook, "Waiting")
-	testutil.AssertLogsContain(t, hook, "Initialized beacon chain genesis state")
-}
-
 func TestChainStartStop_Initialized(t *testing.T) {
 	hook := logTest.NewGlobal()
 	ctx := context.Background()
-	db, sc := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)

-	chainService := setupBeaconChain(t, db, sc)
+	chainService := setupBeaconChain(t, beaconDB)

 	genesisBlk := testutil.NewBeaconBlock()
-	blkRoot, err := stateutil.BlockRoot(genesisBlk.Block)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if err := db.SaveBlock(ctx, genesisBlk); err != nil {
-		t.Fatal(err)
-	}
-	s := testutil.NewBeaconState()
-	if err := s.SetSlot(1); err != nil {
-		t.Fatal(err)
-	}
-	if err := db.SaveState(ctx, s, blkRoot); err != nil {
-		t.Fatal(err)
-	}
-	if err := db.SaveHeadBlockRoot(ctx, blkRoot); err != nil {
-		t.Fatal(err)
-	}
-	if err := db.SaveGenesisBlockRoot(ctx, blkRoot); err != nil {
-		t.Fatal(err)
-	}
-	if err := db.SaveJustifiedCheckpoint(ctx, &ethpb.Checkpoint{Root: blkRoot[:]}); err != nil {
-		t.Fatal(err)
-	}
+	blkRoot, err := genesisBlk.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveBlock(ctx, genesisBlk))
+	s, err := testutil.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, s.SetSlot(1))
+	require.NoError(t, beaconDB.SaveState(ctx, s, blkRoot))
+	require.NoError(t, beaconDB.SaveHeadBlockRoot(ctx, blkRoot))
+	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, blkRoot))
+	require.NoError(t, beaconDB.SaveJustifiedCheckpoint(ctx, &ethpb.Checkpoint{Root: blkRoot[:]}))
+	require.NoError(t, beaconDB.SaveFinalizedCheckpoint(ctx, &ethpb.Checkpoint{Root: blkRoot[:]}))

 	// Test the start function.
 	chainService.Start()

-	if err := chainService.Stop(); err != nil {
-		t.Fatalf("unable to stop chain service: %v", err)
-	}
+	require.NoError(t, chainService.Stop(), "Unable to stop chain service")

 	// The context should have been canceled.
-	if chainService.ctx.Err() != context.Canceled {
-		t.Error("context was not canceled")
-	}
-	testutil.AssertLogsContain(t, hook, "data already exists")
+	assert.Equal(t, context.Canceled, chainService.ctx.Err(), "Context was not canceled")
+	require.LogsContain(t, hook, "data already exists")
+}
+
+func TestChainStartStop_GenesisZeroHashes(t *testing.T) {
+	hook := logTest.NewGlobal()
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+
+	chainService := setupBeaconChain(t, beaconDB)
+
+	genesisBlk := testutil.NewBeaconBlock()
+	blkRoot, err := genesisBlk.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveBlock(ctx, genesisBlk))
+	s, err := testutil.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveState(ctx, s, blkRoot))
+	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, blkRoot))
+	require.NoError(t, beaconDB.SaveJustifiedCheckpoint(ctx, &ethpb.Checkpoint{Root: params.BeaconConfig().ZeroHash[:]}))
+
+	// Test the start function.
+	chainService.Start()
+
+	require.NoError(t, chainService.Stop(), "Unable to stop chain service")
+
+	// The context should have been canceled.
+	assert.Equal(t, context.Canceled, chainService.ctx.Err(), "Context was not canceled")
+	require.LogsContain(t, hook, "data already exists")
 }

 func TestChainService_InitializeBeaconChain(t *testing.T) {
 	helpers.ClearCache()
-	db, sc := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)
 	ctx := context.Background()

-	bc := setupBeaconChain(t, db, sc)
+	bc := setupBeaconChain(t, beaconDB)
 	var err error

 	// Set up 10 deposits pre chain start for validators to register
 	count := uint64(10)
 	deposits, _, err := testutil.DeterministicDepositsAndKeys(count)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 	trie, _, err := testutil.DepositTrieFromDeposits(deposits)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 	hashTreeRoot := trie.HashTreeRoot()
 	genState, err := state.EmptyGenesisState()
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 	err = genState.SetEth1Data(&ethpb.Eth1Data{
 		DepositRoot:  hashTreeRoot[:],
 		DepositCount: uint64(len(deposits)),
+		BlockHash:    make([]byte, 32),
 	})
-	for _, deposit := range deposits {
-		genState, err = b.ProcessPreGenesisDeposit(ctx, genState, deposit)
-		if err != nil {
-			t.Fatal(err)
-		}
-	}
+	require.NoError(t, err)
+	genState, err = b.ProcessPreGenesisDeposits(ctx, genState, deposits)
+	require.NoError(t, err)

-	if _, err := bc.initializeBeaconChain(ctx, time.Unix(0, 0), genState, &ethpb.Eth1Data{
-		DepositRoot: hashTreeRoot[:],
-	}); err != nil {
-		t.Fatal(err)
-	}
+	_, err = bc.initializeBeaconChain(ctx, time.Unix(0, 0), genState, &ethpb.Eth1Data{DepositRoot: hashTreeRoot[:], BlockHash: make([]byte, 32)})
+	require.NoError(t, err)

-	if _, err := bc.HeadState(ctx); err != nil {
-		t.Error(err)
-	}
+	_, err = bc.HeadState(ctx)
+	assert.NoError(t, err)
 	headBlk, err := bc.HeadBlock(ctx)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 	if headBlk == nil {
 		t.Error("Head state can't be nil after initialize beacon chain")
 	}
-	if bc.headRoot() == params.BeaconConfig().ZeroHash {
+	r, err := bc.HeadRoot(ctx)
+	require.NoError(t, err)
+	if bytesutil.ToBytes32(r) == params.BeaconConfig().ZeroHash {
 		t.Error("Canonical root for slot 0 can't be zeros after initialize beacon chain")
 	}
 }

+func TestChainService_CorrectGenesisRoots(t *testing.T) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+
+	chainService := setupBeaconChain(t, beaconDB)
+
+	genesisBlk := testutil.NewBeaconBlock()
+	blkRoot, err := genesisBlk.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveBlock(ctx, genesisBlk))
+	s, err := testutil.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, s.SetSlot(0))
+	require.NoError(t, beaconDB.SaveState(ctx, s, blkRoot))
+	require.NoError(t, beaconDB.SaveHeadBlockRoot(ctx, blkRoot))
+	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, blkRoot))
+	require.NoError(t, beaconDB.SaveFinalizedCheckpoint(ctx, &ethpb.Checkpoint{Root: blkRoot[:]}))
+
+	// Test the start function.
+	chainService.Start()
+
+	require.DeepEqual(t, blkRoot[:], chainService.finalizedCheckpt.Root, "Finalize Checkpoint root is incorrect")
+	require.DeepEqual(t, params.BeaconConfig().ZeroHash[:], chainService.justifiedCheckpt.Root, "Justified Checkpoint root is incorrect")
+
+	require.NoError(t, chainService.Stop(), "Unable to stop chain service")
+
+}
+
 func TestChainService_InitializeChainInfo(t *testing.T) {
-	db, sc := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)
 	ctx := context.Background()

 	genesis := testutil.NewBeaconBlock()
-	genesisRoot, err := stateutil.BlockRoot(genesis.Block)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if err := db.SaveGenesisBlockRoot(ctx, genesisRoot); err != nil {
-		t.Fatal(err)
-	}
-	if err := db.SaveBlock(ctx, genesis); err != nil {
-		t.Fatal(err)
-	}
+	genesisRoot, err := genesis.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, genesisRoot))
+	require.NoError(t, beaconDB.SaveBlock(ctx, genesis))

 	finalizedSlot := params.BeaconConfig().SlotsPerEpoch*2 + 1
 	headBlock := testutil.NewBeaconBlock()
 	headBlock.Block.Slot = finalizedSlot
 	headBlock.Block.ParentRoot = bytesutil.PadTo(genesisRoot[:], 32)
-	headState := testutil.NewBeaconState()
-	if err := headState.SetSlot(finalizedSlot); err != nil {
-		t.Fatal(err)
-	}
-	if err := headState.SetGenesisValidatorRoot(params.BeaconConfig().ZeroHash[:]); err != nil {
-		t.Fatal(err)
-	}
-	headRoot, err := stateutil.BlockRoot(headBlock.Block)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if err := db.SaveState(ctx, headState, headRoot); err != nil {
-		t.Fatal(err)
-	}
-	if err := db.SaveState(ctx, headState, genesisRoot); err != nil {
-		t.Fatal(err)
-	}
-	if err := db.SaveBlock(ctx, headBlock); err != nil {
-		t.Fatal(err)
-	}
-	if err := db.SaveFinalizedCheckpoint(ctx, &ethpb.Checkpoint{
-		Epoch: helpers.SlotToEpoch(finalizedSlot),
-		Root:  headRoot[:],
-	}); err != nil {
-		t.Fatal(err)
-	}
-	c := &Service{beaconDB: db, stateGen: stategen.New(db, sc)}
-	if err := c.initializeChainInfo(ctx); err != nil {
-		t.Fatal(err)
-	}
+	headState, err := testutil.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, headState.SetSlot(finalizedSlot))
+	require.NoError(t, headState.SetGenesisValidatorRoot(params.BeaconConfig().ZeroHash[:]))
+	headRoot, err := headBlock.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveState(ctx, headState, headRoot))
+	require.NoError(t, beaconDB.SaveState(ctx, headState, genesisRoot))
+	require.NoError(t, beaconDB.SaveBlock(ctx, headBlock))
+	require.NoError(t, beaconDB.SaveFinalizedCheckpoint(ctx, &ethpb.Checkpoint{Epoch: helpers.SlotToEpoch(finalizedSlot), Root: headRoot[:]}))
+	c := &Service{cfg: &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)}}
+	require.NoError(t, c.initializeChainInfo(ctx))
 	headBlk, err := c.HeadBlock(ctx)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !reflect.DeepEqual(headBlk, headBlock) {
-		t.Error("head block incorrect")
-	}
+	require.NoError(t, err)
+	assert.DeepEqual(t, headBlock, headBlk, "Head block incorrect")
 	s, err := c.HeadState(ctx)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !reflect.DeepEqual(s.InnerStateUnsafe(), headState.InnerStateUnsafe()) {
-		t.Error("head state incorrect")
-	}
-	if headBlock.Block.Slot != c.HeadSlot() {
-		t.Error("head slot incorrect")
-	}
+	require.NoError(t, err)
+	assert.DeepSSZEqual(t, headState.InnerStateUnsafe(), s.InnerStateUnsafe(), "Head state incorrect")
+	assert.Equal(t, c.HeadSlot(), headBlock.Block.Slot, "Head slot incorrect")
 	r, err := c.HeadRoot(context.Background())
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 	if !bytes.Equal(headRoot[:], r) {
 		t.Error("head slot incorrect")
 	}
-	if c.genesisRoot != genesisRoot {
-		t.Error("genesis block root incorrect")
-	}
+	assert.Equal(t, genesisRoot, c.genesisRoot, "Genesis block root incorrect")
+}
+
+func TestChainService_InitializeChainInfo_SetHeadAtGenesis(t *testing.T) {
+	beaconDB := testDB.SetupDB(t)
+	ctx := context.Background()
+
+	genesis := testutil.NewBeaconBlock()
+	genesisRoot, err := genesis.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, genesisRoot))
+	require.NoError(t, beaconDB.SaveBlock(ctx, genesis))
+
+	finalizedSlot := params.BeaconConfig().SlotsPerEpoch*2 + 1
+	headBlock := testutil.NewBeaconBlock()
+	headBlock.Block.Slot = finalizedSlot
+	headBlock.Block.ParentRoot = bytesutil.PadTo(genesisRoot[:], 32)
+	headState, err := testutil.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, headState.SetSlot(finalizedSlot))
+	require.NoError(t, headState.SetGenesisValidatorRoot(params.BeaconConfig().ZeroHash[:]))
+	headRoot, err := headBlock.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveState(ctx, headState, headRoot))
+	require.NoError(t, beaconDB.SaveState(ctx, headState, genesisRoot))
+	require.NoError(t, beaconDB.SaveBlock(ctx, headBlock))
+	c := &Service{cfg: &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)}}
+	require.NoError(t, c.initializeChainInfo(ctx))
+	s, err := c.HeadState(ctx)
+	require.NoError(t, err)
+	assert.DeepSSZEqual(t, headState.InnerStateUnsafe(), s.InnerStateUnsafe(), "Head state incorrect")
+	assert.Equal(t, genesisRoot, c.genesisRoot, "Genesis block root incorrect")
+	assert.DeepEqual(t, genesis, c.head.block)
+}
+
+func TestChainService_InitializeChainInfo_HeadSync(t *testing.T) {
+	resetFlags := flags.Get()
+	flags.Init(&flags.GlobalFlags{
+		HeadSync: true,
+	})
+	defer func() {
+		flags.Init(resetFlags)
+	}()
+
+	hook := logTest.NewGlobal()
+	finalizedSlot := params.BeaconConfig().SlotsPerEpoch*2 + 1
+	beaconDB := testDB.SetupDB(t)
+	ctx := context.Background()
+
+	genesisBlock := testutil.NewBeaconBlock()
+	genesisRoot, err := genesisBlock.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, genesisRoot))
+	require.NoError(t, beaconDB.SaveBlock(ctx, genesisBlock))
+
+	finalizedBlock := testutil.NewBeaconBlock()
+	finalizedBlock.Block.Slot = finalizedSlot
+	finalizedBlock.Block.ParentRoot = genesisRoot[:]
+	finalizedRoot, err := finalizedBlock.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveBlock(ctx, finalizedBlock))
+
+	// Set head slot close to the finalization point, no head sync is triggered.
+	headBlock := testutil.NewBeaconBlock()
+	headBlock.Block.Slot = finalizedSlot + params.BeaconConfig().SlotsPerEpoch*5
+	headBlock.Block.ParentRoot = finalizedRoot[:]
+	headRoot, err := headBlock.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveBlock(ctx, headBlock))
+
+	headState, err := testutil.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, headState.SetSlot(headBlock.Block.Slot))
+	require.NoError(t, headState.SetGenesisValidatorRoot(params.BeaconConfig().ZeroHash[:]))
+	require.NoError(t, beaconDB.SaveState(ctx, headState, genesisRoot))
+	require.NoError(t, beaconDB.SaveState(ctx, headState, finalizedRoot))
+	require.NoError(t, beaconDB.SaveState(ctx, headState, headRoot))
+	require.NoError(t, beaconDB.SaveHeadBlockRoot(ctx, headRoot))
+	require.NoError(t, beaconDB.SaveFinalizedCheckpoint(ctx, &ethpb.Checkpoint{
+		Epoch: helpers.SlotToEpoch(finalizedBlock.Block.Slot),
+		Root:  finalizedRoot[:],
+	}))
+
+	c := &Service{cfg: &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)}}
+
+	require.NoError(t, c.initializeChainInfo(ctx))
+	s, err := c.HeadState(ctx)
+	require.NoError(t, err)
+	assert.DeepSSZEqual(t, headState.InnerStateUnsafe(), s.InnerStateUnsafe(), "Head state incorrect")
+	assert.Equal(t, genesisRoot, c.genesisRoot, "Genesis block root incorrect")
+	// Since head sync is not triggered, chain is initialized to the last finalization checkpoint.
+	assert.DeepEqual(t, finalizedBlock, c.head.block)
+	assert.LogsContain(t, hook, "resetting head from the checkpoint ('--head-sync' flag is ignored)")
+	assert.LogsDoNotContain(t, hook, "Regenerating state from the last checkpoint at slot")
+
+	// Set head slot far beyond the finalization point, head sync should be triggered.
+	headBlock = testutil.NewBeaconBlock()
+	headBlock.Block.Slot = finalizedSlot + params.BeaconConfig().SlotsPerEpoch*headSyncMinEpochsAfterCheckpoint
+	headBlock.Block.ParentRoot = finalizedRoot[:]
+	headRoot, err = headBlock.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveBlock(ctx, headBlock))
+	require.NoError(t, beaconDB.SaveState(ctx, headState, headRoot))
+	require.NoError(t, beaconDB.SaveHeadBlockRoot(ctx, headRoot))
+
+	hook.Reset()
+	require.NoError(t, c.initializeChainInfo(ctx))
+	s, err = c.HeadState(ctx)
+	require.NoError(t, err)
+	assert.DeepSSZEqual(t, headState.InnerStateUnsafe(), s.InnerStateUnsafe(), "Head state incorrect")
+	assert.Equal(t, genesisRoot, c.genesisRoot, "Genesis block root incorrect")
+	// Head slot is far beyond the latest finalized checkpoint, head sync is triggered.
+	assert.DeepEqual(t, headBlock, c.head.block)
+	assert.LogsContain(t, hook, "Regenerating state from the last checkpoint at slot 225")
+	assert.LogsDoNotContain(t, hook, "resetting head from the checkpoint ('--head-sync' flag is ignored)")
 }

 func TestChainService_SaveHeadNoDB(t *testing.T) {
-	db, sc := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)
 	ctx := context.Background()
 	s := &Service{
-		beaconDB: db,
-		stateGen: stategen.New(db, sc),
-	}
-	b := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Slot: 1}}
-	r, err := ssz.HashTreeRoot(b)
-	if err != nil {
-		t.Fatal(err)
-	}
-	newState := testutil.NewBeaconState()
-	if err := s.stateGen.SaveState(ctx, r, newState); err != nil {
-		t.Fatal(err)
+		cfg: &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)},
 	}
+	blk := testutil.NewBeaconBlock()
+	blk.Block.Slot = 1
+	r, err := blk.HashTreeRoot()
+	require.NoError(t, err)
+	newState, err := testutil.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, s.cfg.StateGen.SaveState(ctx, r, newState))
+	require.NoError(t, s.saveHeadNoDB(ctx, blk, r, newState))

-	if err := s.saveHeadNoDB(ctx, b, r); err != nil {
-		t.Fatal(err)
-	}
-
-	newB, err := s.beaconDB.HeadBlock(ctx)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if reflect.DeepEqual(newB, b) {
+	newB, err := s.cfg.BeaconDB.HeadBlock(ctx)
+	require.NoError(t, err)
+	if reflect.DeepEqual(newB, blk) {
 		t.Error("head block should not be equal")
 	}
 }

-func TestChainService_PruneOldStates(t *testing.T) {
-	db, _ := testDB.SetupDB(t)
-	ctx := context.Background()
-	s := &Service{
-		beaconDB: db,
-	}
-
-	for i := 0; i < 100; i++ {
-		block := &ethpb.BeaconBlock{Slot: uint64(i)}
-		if err := s.beaconDB.SaveBlock(ctx, &ethpb.SignedBeaconBlock{Block: block}); err != nil {
-			t.Fatal(err)
-		}
-		r, err := stateutil.BlockRoot(block)
-		if err != nil {
-			t.Fatal(err)
-		}
-		newState := testutil.NewBeaconState()
-		if err := newState.SetSlot(uint64(i)); err != nil {
-			t.Fatal(err)
-		}
-		if err := s.beaconDB.SaveState(ctx, newState, r); err != nil {
-			t.Fatal(err)
-		}
-	}
-
-	// Delete half of the states.
-	if err := s.pruneGarbageState(ctx, 50); err != nil {
-		t.Fatal(err)
-	}
-
-	filter := filters.NewFilter().SetStartSlot(1).SetEndSlot(100)
-	roots, err := s.beaconDB.BlockRoots(ctx, filter)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	for i := 1; i < 50; i++ {
-		s, err := s.beaconDB.State(ctx, roots[i])
-		if err != nil {
-			t.Fatal(err)
-		}
-		if s != nil {
-			t.Errorf("wanted nil for slot %d", i)
-		}
-	}
-}
-
 func TestHasBlock_ForkChoiceAndDB(t *testing.T) {
 	ctx := context.Background()
-	db, _ := testDB.SetupDB(t)
+	beaconDB := testDB.SetupDB(t)
 	s := &Service{
-		forkChoiceStore:  protoarray.New(0, 0, [32]byte{}),
-		finalizedCheckpt: &ethpb.Checkpoint{},
-		beaconDB:         db,
-	}
-	block := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{}}}
-	r, err := stateutil.BlockRoot(block.Block)
-	if err != nil {
-		t.Fatal(err)
-	}
-	bs := &pb.BeaconState{FinalizedCheckpoint: &ethpb.Checkpoint{}, CurrentJustifiedCheckpoint: &ethpb.Checkpoint{}}
-	state, err := beaconstate.InitializeFromProto(bs)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if err := s.insertBlockToForkChoiceStore(ctx, block.Block, r, state); err != nil {
-		t.Fatal(err)
+		cfg:              &Config{ForkChoiceStore: protoarray.New(0, 0, [32]byte{}), BeaconDB: beaconDB},
+		finalizedCheckpt: &ethpb.Checkpoint{Root: make([]byte, 32)},
 	}
+	block := testutil.NewBeaconBlock()
+	r, err := block.Block.HashTreeRoot()
+	require.NoError(t, err)
+	beaconState, err := testutil.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, s.insertBlockAndAttestationsToForkChoiceStore(ctx, block.Block, r, beaconState))

-	if s.hasBlock(ctx, [32]byte{}) {
-		t.Error("Should not have block")
-	}
+	assert.Equal(t, false, s.hasBlock(ctx, [32]byte{}), "Should not have block")
+	assert.Equal(t, true, s.hasBlock(ctx, r), "Should have block")
+}

-	if !s.hasBlock(ctx, r) {
-		t.Error("Should have block")
+func TestServiceStop_SaveCachedBlocks(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	beaconDB := testDB.SetupDB(t)
+	s := &Service{
+		cfg:            &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)},
+		ctx:            ctx,
+		cancel:         cancel,
+		initSyncBlocks: make(map[[32]byte]*ethpb.SignedBeaconBlock),
 	}
+	b := testutil.NewBeaconBlock()
+	r, err := b.Block.HashTreeRoot()
+	require.NoError(t, err)
+	s.saveInitSyncBlock(r, b)
+	require.NoError(t, s.Stop())
+	require.Equal(t, true, s.cfg.BeaconDB.HasBlock(ctx, r))
+}
+
+func TestProcessChainStartTime_ReceivedFeed(t *testing.T) {
+	beaconDB := testDB.SetupDB(t)
+	service := setupBeaconChain(t, beaconDB)
+	stateChannel := make(chan *feed.Event, 1)
+	stateSub := service.cfg.StateNotifier.StateFeed().Subscribe(stateChannel)
+	defer stateSub.Unsubscribe()
+	service.processChainStartTime(context.Background(), time.Now())
+
+	stateEvent := <-stateChannel
+	require.Equal(t, int(stateEvent.Type), statefeed.Initialized)
+	_, ok := stateEvent.Data.(*statefeed.InitializedData)
+	require.Equal(t, true, ok)
 }

 func BenchmarkHasBlockDB(b *testing.B) {
-	db, _ := testDB.SetupDB(b)
+	beaconDB := testDB.SetupDB(b)
 	ctx := context.Background()
 	s := &Service{
-		beaconDB: db,
-	}
-	block := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{}}
-	if err := s.beaconDB.SaveBlock(ctx, block); err != nil {
-		b.Fatal(err)
-	}
-	r, err := stateutil.BlockRoot(block.Block)
-	if err != nil {
-		b.Fatal(err)
+		cfg: &Config{BeaconDB: beaconDB},
 	}
+	block := testutil.NewBeaconBlock()
+	require.NoError(b, s.cfg.BeaconDB.SaveBlock(ctx, block))
+	r, err := block.Block.HashTreeRoot()
+	require.NoError(b, err)

 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		if !s.beaconDB.HasBlock(ctx, r) {
-			b.Fatal("Block is not in DB")
-		}
+		require.Equal(b, true, s.cfg.BeaconDB.HasBlock(ctx, r), "Block is not in DB")
 	}
 }

 func BenchmarkHasBlockForkChoiceStore(b *testing.B) {
 	ctx := context.Background()
-	db, _ := testDB.SetupDB(b)
+	beaconDB := testDB.SetupDB(b)
 	s := &Service{
-		forkChoiceStore:  protoarray.New(0, 0, [32]byte{}),
-		finalizedCheckpt: &ethpb.Checkpoint{},
-		beaconDB:         db,
+		cfg:              &Config{ForkChoiceStore: protoarray.New(0, 0, [32]byte{}), BeaconDB: beaconDB},
+		finalizedCheckpt: &ethpb.Checkpoint{Root: make([]byte, 32)},
 	}
 	block := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{}}}
-	r, err := stateutil.BlockRoot(block.Block)
-	if err != nil {
-		b.Fatal(err)
-	}
-	bs := &pb.BeaconState{FinalizedCheckpoint: &ethpb.Checkpoint{}, CurrentJustifiedCheckpoint: &ethpb.Checkpoint{}}
-	state, err := beaconstate.InitializeFromProto(bs)
-	if err != nil {
-		b.Fatal(err)
-	}
-	if err := s.insertBlockToForkChoiceStore(ctx, block.Block, r, state); err != nil {
-		b.Fatal(err)
-	}
+	r, err := block.Block.HashTreeRoot()
+	require.NoError(b, err)
+	bs := &pb.BeaconState{FinalizedCheckpoint: &ethpb.Checkpoint{Root: make([]byte, 32)}, CurrentJustifiedCheckpoint: &ethpb.Checkpoint{Root: make([]byte, 32)}}
+	beaconState, err := stateV0.InitializeFromProto(bs)
+	require.NoError(b, err)
+	require.NoError(b, s.insertBlockAndAttestationsToForkChoiceStore(ctx, block.Block, r, beaconState))

 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		if !s.forkChoiceStore.HasNode(r) {
-			b.Fatal("Block is not in fork choice store")
-		}
+		require.Equal(b, true, s.cfg.ForkChoiceStore.HasNode(r), "Block is not in fork choice store")
 	}
 }
--- a/beacon-chain/blockchain/testing/BUILD.bazel
+++ b/beacon-chain/blockchain/testing/BUILD.bazel
@@ -11,18 +11,21 @@ go_library(
    ],
    deps = [
        "//beacon-chain/core/epoch/precompute:go_default_library",
+        "//beacon-chain/core/feed:go_default_library",
        "//beacon-chain/core/feed/block:go_default_library",
        "//beacon-chain/core/feed/operation:go_default_library",
        "//beacon-chain/core/feed/state:go_default_library",
        "//beacon-chain/core/helpers:go_default_library",
        "//beacon-chain/db:go_default_library",
        "//beacon-chain/forkchoice/protoarray:go_default_library",
-        "//beacon-chain/state:go_default_library",
-        "//beacon-chain/state/stateutil:go_default_library",
+        "//beacon-chain/state/interface:go_default_library",
+        "//beacon-chain/state/stateV0:go_default_library",
        "//proto/beacon/p2p/v1:go_default_library",
+        "//shared/bytesutil:go_default_library",
        "//shared/event:go_default_library",
        "//shared/params:go_default_library",
        "@com_github_pkg_errors//:go_default_library",
+        "@com_github_prysmaticlabs_eth2_types//:go_default_library",
        "@com_github_prysmaticlabs_ethereumapis//eth/v1alpha1:go_default_library",
        "@com_github_sirupsen_logrus//:go_default_library",
    ],
--- a/beacon-chain/blockchain/testing/mock.go
+++ b/beacon-chain/blockchain/testing/mock.go
@@ -5,20 +5,24 @@ package testing
 import (
 	"bytes"
 	"context"
+	"sync"
 	"time"

 	"github.com/pkg/errors"
+	types "github.com/prysmaticlabs/eth2-types"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/epoch/precompute"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/feed"
 	blockfeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/block"
 	opfeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/operation"
 	statefeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/beacon-chain/db"
 	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateutil"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateV0"
 	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/event"
 	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/sirupsen/logrus"
@@ -26,7 +30,7 @@ import (

 // ChainService defines the mock interface for testing
 type ChainService struct {
-	State                       *stateTrie.BeaconState
+	State                       iface.BeaconState
 	Root                        []byte
 	Block                       *ethpb.SignedBeaconBlock
 	FinalizedCheckPoint         *ethpb.Checkpoint
@@ -36,6 +40,7 @@ type ChainService struct {
 	Balance                     *precompute.Balance
 	Genesis                     time.Time
 	ValidatorsRoot              [32]byte
+	CanonicalRoots              map[[32]byte]bool
 	Fork                        *pb.Fork
 	ETH1Data                    *ethpb.Eth1Data
 	DB                          db.Database
@@ -44,22 +49,24 @@ type ChainService struct {
 	opNotifier                  opfeed.Notifier
 	ValidAttestation            bool
 	ForkChoiceStore             *protoarray.Store
+	VerifyBlkDescendantErr      error
+	Slot                        *types.Slot // Pointer because 0 is a useful value, so checking against it can be incorrect.
 }

 // StateNotifier mocks the same method in the chain service.
-func (ms *ChainService) StateNotifier() statefeed.Notifier {
-	if ms.stateNotifier == nil {
-		ms.stateNotifier = &MockStateNotifier{}
+func (s *ChainService) StateNotifier() statefeed.Notifier {
+	if s.stateNotifier == nil {
+		s.stateNotifier = &MockStateNotifier{}
 	}
-	return ms.stateNotifier
+	return s.stateNotifier
 }

 // BlockNotifier mocks the same method in the chain service.
-func (ms *ChainService) BlockNotifier() blockfeed.Notifier {
-	if ms.blockNotifier == nil {
-		ms.blockNotifier = &MockBlockNotifier{}
+func (s *ChainService) BlockNotifier() blockfeed.Notifier {
+	if s.blockNotifier == nil {
+		s.blockNotifier = &MockBlockNotifier{}
 	}
-	return ms.blockNotifier
+	return s.blockNotifier
 }

 // MockBlockNotifier mocks the block notifier.
@@ -68,32 +75,64 @@ type MockBlockNotifier struct {
 }

 // BlockFeed returns a block feed.
-func (msn *MockBlockNotifier) BlockFeed() *event.Feed {
-	if msn.feed == nil {
-		msn.feed = new(event.Feed)
+func (mbn *MockBlockNotifier) BlockFeed() *event.Feed {
+	if mbn.feed == nil {
+		mbn.feed = new(event.Feed)
 	}
-	return msn.feed
+	return mbn.feed
 }

 // MockStateNotifier mocks the state notifier.
 type MockStateNotifier struct {
-	feed *event.Feed
+	feed     *event.Feed
+	feedLock sync.Mutex
+
+	recv     []*feed.Event
+	recvLock sync.Mutex
+	recvCh   chan *feed.Event
+
+	RecordEvents bool
+}
+
+// ReceivedEvents returns the events received by the state feed in this mock.
+func (msn *MockStateNotifier) ReceivedEvents() []*feed.Event {
+	msn.recvLock.Lock()
+	defer msn.recvLock.Unlock()
+	return msn.recv
 }

 // StateFeed returns a state feed.
 func (msn *MockStateNotifier) StateFeed() *event.Feed {
-	if msn.feed == nil {
+	msn.feedLock.Lock()
+	defer msn.feedLock.Unlock()
+
+	if msn.feed == nil && msn.recvCh == nil {
 		msn.feed = new(event.Feed)
+		if msn.RecordEvents {
+			msn.recvCh = make(chan *feed.Event)
+			sub := msn.feed.Subscribe(msn.recvCh)
+
+			go func() {
+				select {
+				case evt := <-msn.recvCh:
+					msn.recvLock.Lock()
+					msn.recv = append(msn.recv, evt)
+					msn.recvLock.Unlock()
+				case <-sub.Err():
+					sub.Unsubscribe()
+				}
+			}()
+		}
 	}
 	return msn.feed
 }

 // OperationNotifier mocks the same method in the chain service.
-func (ms *ChainService) OperationNotifier() opfeed.Notifier {
-	if ms.opNotifier == nil {
-		ms.opNotifier = &MockOperationNotifier{}
+func (s *ChainService) OperationNotifier() opfeed.Notifier {
+	if s.opNotifier == nil {
+		s.opNotifier = &MockOperationNotifier{}
 	}
-	return ms.opNotifier
+	return s.opNotifier
 }

 // MockOperationNotifier mocks the operation notifier.
@@ -109,187 +148,247 @@ func (mon *MockOperationNotifier) OperationFeed() *event.Feed {
 	return mon.feed
 }

-// ReceiveBlock mocks ReceiveBlock method in chain service.
-func (ms *ChainService) ReceiveBlock(ctx context.Context, block *ethpb.SignedBeaconBlock, blockRoot [32]byte) error {
-	return nil
-}
-
 // ReceiveBlockInitialSync mocks ReceiveBlockInitialSync method in chain service.
-func (ms *ChainService) ReceiveBlockInitialSync(ctx context.Context, block *ethpb.SignedBeaconBlock, blockRoot [32]byte) error {
-	if ms.State == nil {
-		ms.State = &stateTrie.BeaconState{}
+func (s *ChainService) ReceiveBlockInitialSync(ctx context.Context, block *ethpb.SignedBeaconBlock, _ [32]byte) error {
+	if s.State == nil {
+		s.State = &stateV0.BeaconState{}
 	}
-	if !bytes.Equal(ms.Root, block.Block.ParentRoot) {
-		return errors.Errorf("wanted %#x but got %#x", ms.Root, block.Block.ParentRoot)
+	if !bytes.Equal(s.Root, block.Block.ParentRoot) {
+		return errors.Errorf("wanted %#x but got %#x", s.Root, block.Block.ParentRoot)
 	}
-	if err := ms.State.SetSlot(block.Block.Slot); err != nil {
+	if err := s.State.SetSlot(block.Block.Slot); err != nil {
 		return err
 	}
-	ms.BlocksReceived = append(ms.BlocksReceived, block)
-	signingRoot, err := stateutil.BlockRoot(block.Block)
+	s.BlocksReceived = append(s.BlocksReceived, block)
+	signingRoot, err := block.Block.HashTreeRoot()
 	if err != nil {
 		return err
 	}
-	if ms.DB != nil {
-		if err := ms.DB.SaveBlock(ctx, block); err != nil {
+	if s.DB != nil {
+		if err := s.DB.SaveBlock(ctx, block); err != nil {
 			return err
 		}
 		logrus.Infof("Saved block with root: %#x at slot %d", signingRoot, block.Block.Slot)
 	}
-	ms.Root = signingRoot[:]
-	ms.Block = block
+	s.Root = signingRoot[:]
+	s.Block = block
 	return nil
 }

-// ReceiveBlockNoPubsub mocks ReceiveBlockNoPubsub method in chain service.
-func (ms *ChainService) ReceiveBlockNoPubsub(ctx context.Context, block *ethpb.SignedBeaconBlock, blockRoot [32]byte) error {
-	if ms.State == nil {
-		ms.State = &stateTrie.BeaconState{}
+// ReceiveBlockBatch processes blocks in batches from initial-sync.
+func (s *ChainService) ReceiveBlockBatch(ctx context.Context, blks []*ethpb.SignedBeaconBlock, _ [][32]byte) error {
+	if s.State == nil {
+		s.State = &stateV0.BeaconState{}
 	}
-	if !bytes.Equal(ms.Root, block.Block.ParentRoot) {
-		return errors.Errorf("wanted %#x but got %#x", ms.Root, block.Block.ParentRoot)
+	for _, block := range blks {
+		if !bytes.Equal(s.Root, block.Block.ParentRoot) {
+			return errors.Errorf("wanted %#x but got %#x", s.Root, block.Block.ParentRoot)
+		}
+		if err := s.State.SetSlot(block.Block.Slot); err != nil {
+			return err
+		}
+		s.BlocksReceived = append(s.BlocksReceived, block)
+		signingRoot, err := block.Block.HashTreeRoot()
+		if err != nil {
+			return err
+		}
+		if s.DB != nil {
+			if err := s.DB.SaveBlock(ctx, block); err != nil {
+				return err
+			}
+			logrus.Infof("Saved block with root: %#x at slot %d", signingRoot, block.Block.Slot)
+		}
+		s.Root = signingRoot[:]
+		s.Block = block
 	}
-	if err := ms.State.SetSlot(block.Block.Slot); err != nil {
+	return nil
+}
+
+// ReceiveBlock mocks ReceiveBlock method in chain service.
+func (s *ChainService) ReceiveBlock(ctx context.Context, block *ethpb.SignedBeaconBlock, _ [32]byte) error {
+	if s.State == nil {
+		s.State = &stateV0.BeaconState{}
+	}
+	if !bytes.Equal(s.Root, block.Block.ParentRoot) {
+		return errors.Errorf("wanted %#x but got %#x", s.Root, block.Block.ParentRoot)
+	}
+	if err := s.State.SetSlot(block.Block.Slot); err != nil {
 		return err
 	}
-	ms.BlocksReceived = append(ms.BlocksReceived, block)
-	signingRoot, err := stateutil.BlockRoot(block.Block)
+	s.BlocksReceived = append(s.BlocksReceived, block)
+	signingRoot, err := block.Block.HashTreeRoot()
 	if err != nil {
 		return err
 	}
-	if ms.DB != nil {
-		if err := ms.DB.SaveBlock(ctx, block); err != nil {
+	if s.DB != nil {
+		if err := s.DB.SaveBlock(ctx, block); err != nil {
 			return err
 		}
 		logrus.Infof("Saved block with root: %#x at slot %d", signingRoot, block.Block.Slot)
 	}
-	ms.Root = signingRoot[:]
-	ms.Block = block
+	s.Root = signingRoot[:]
+	s.Block = block
 	return nil
 }

 // HeadSlot mocks HeadSlot method in chain service.
-func (ms *ChainService) HeadSlot() uint64 {
-	if ms.State == nil {
+func (s *ChainService) HeadSlot() types.Slot {
+	if s.State == nil {
 		return 0
 	}
-	return ms.State.Slot()
+	return s.State.Slot()
 }

 // HeadRoot mocks HeadRoot method in chain service.
-func (ms *ChainService) HeadRoot(ctx context.Context) ([]byte, error) {
-	return ms.Root, nil
-
+func (s *ChainService) HeadRoot(_ context.Context) ([]byte, error) {
+	if len(s.Root) > 0 {
+		return s.Root, nil
+	}
+	return make([]byte, 32), nil
 }

 // HeadBlock mocks HeadBlock method in chain service.
-func (ms *ChainService) HeadBlock(context.Context) (*ethpb.SignedBeaconBlock, error) {
-	return ms.Block, nil
+func (s *ChainService) HeadBlock(context.Context) (*ethpb.SignedBeaconBlock, error) {
+	return s.Block, nil
 }

 // HeadState mocks HeadState method in chain service.
-func (ms *ChainService) HeadState(context.Context) (*stateTrie.BeaconState, error) {
-	return ms.State, nil
+func (s *ChainService) HeadState(context.Context) (iface.BeaconState, error) {
+	return s.State, nil
 }

 // CurrentFork mocks HeadState method in chain service.
-func (ms *ChainService) CurrentFork() *pb.Fork {
-	return ms.Fork
+func (s *ChainService) CurrentFork() *pb.Fork {
+	return s.Fork
 }

 // FinalizedCheckpt mocks FinalizedCheckpt method in chain service.
-func (ms *ChainService) FinalizedCheckpt() *ethpb.Checkpoint {
-	return ms.FinalizedCheckPoint
+func (s *ChainService) FinalizedCheckpt() *ethpb.Checkpoint {
+	return s.FinalizedCheckPoint
 }

 // CurrentJustifiedCheckpt mocks CurrentJustifiedCheckpt method in chain service.
-func (ms *ChainService) CurrentJustifiedCheckpt() *ethpb.Checkpoint {
-	return ms.CurrentJustifiedCheckPoint
+func (s *ChainService) CurrentJustifiedCheckpt() *ethpb.Checkpoint {
+	return s.CurrentJustifiedCheckPoint
 }

 // PreviousJustifiedCheckpt mocks PreviousJustifiedCheckpt method in chain service.
-func (ms *ChainService) PreviousJustifiedCheckpt() *ethpb.Checkpoint {
-	return ms.PreviousJustifiedCheckPoint
+func (s *ChainService) PreviousJustifiedCheckpt() *ethpb.Checkpoint {
+	return s.PreviousJustifiedCheckPoint
 }

 // ReceiveAttestation mocks ReceiveAttestation method in chain service.
-func (ms *ChainService) ReceiveAttestation(context.Context, *ethpb.Attestation) error {
+func (s *ChainService) ReceiveAttestation(_ context.Context, _ *ethpb.Attestation) error {
 	return nil
 }

 // ReceiveAttestationNoPubsub mocks ReceiveAttestationNoPubsub method in chain service.
-func (ms *ChainService) ReceiveAttestationNoPubsub(context.Context, *ethpb.Attestation) error {
+func (s *ChainService) ReceiveAttestationNoPubsub(context.Context, *ethpb.Attestation) error {
 	return nil
 }

 // AttestationPreState mocks AttestationPreState method in chain service.
-func (ms *ChainService) AttestationPreState(ctx context.Context, att *ethpb.Attestation) (*stateTrie.BeaconState, error) {
-	return ms.State, nil
+func (s *ChainService) AttestationPreState(_ context.Context, _ *ethpb.Attestation) (iface.BeaconState, error) {
+	return s.State, nil
 }

 // HeadValidatorsIndices mocks the same method in the chain service.
-func (ms *ChainService) HeadValidatorsIndices(ctx context.Context, epoch uint64) ([]uint64, error) {
-	if ms.State == nil {
-		return []uint64{}, nil
+func (s *ChainService) HeadValidatorsIndices(_ context.Context, epoch types.Epoch) ([]types.ValidatorIndex, error) {
+	if s.State == nil {
+		return []types.ValidatorIndex{}, nil
 	}
-	return helpers.ActiveValidatorIndices(ms.State, epoch)
+	return helpers.ActiveValidatorIndices(s.State, epoch)
 }

 // HeadSeed mocks the same method in the chain service.
-func (ms *ChainService) HeadSeed(ctx context.Context, epoch uint64) ([32]byte, error) {
-	return helpers.Seed(ms.State, epoch, params.BeaconConfig().DomainBeaconAttester)
+func (s *ChainService) HeadSeed(_ context.Context, epoch types.Epoch) ([32]byte, error) {
+	return helpers.Seed(s.State, epoch, params.BeaconConfig().DomainBeaconAttester)
 }

 // HeadETH1Data provides the current ETH1Data of the head state.
-func (ms *ChainService) HeadETH1Data() *ethpb.Eth1Data {
-	return ms.ETH1Data
+func (s *ChainService) HeadETH1Data() *ethpb.Eth1Data {
+	return s.ETH1Data
 }

 // ProtoArrayStore mocks the same method in the chain service.
-func (ms *ChainService) ProtoArrayStore() *protoarray.Store {
-	return ms.ForkChoiceStore
+func (s *ChainService) ProtoArrayStore() *protoarray.Store {
+	return s.ForkChoiceStore
 }

 // GenesisTime mocks the same method in the chain service.
-func (ms *ChainService) GenesisTime() time.Time {
-	return ms.Genesis
+func (s *ChainService) GenesisTime() time.Time {
+	return s.Genesis
 }

 // GenesisValidatorRoot mocks the same method in the chain service.
-func (ms *ChainService) GenesisValidatorRoot() [32]byte {
-	return ms.ValidatorsRoot
+func (s *ChainService) GenesisValidatorRoot() [32]byte {
+	return s.ValidatorsRoot
 }

 // CurrentSlot mocks the same method in the chain service.
-func (ms *ChainService) CurrentSlot() uint64 {
-	return uint64(time.Now().Unix()-ms.Genesis.Unix()) / params.BeaconConfig().SecondsPerSlot
+func (s *ChainService) CurrentSlot() types.Slot {
+	if s.Slot != nil {
+		return *s.Slot
+	}
+	return types.Slot(uint64(time.Now().Unix()-s.Genesis.Unix()) / params.BeaconConfig().SecondsPerSlot)
 }

 // Participation mocks the same method in the chain service.
-func (ms *ChainService) Participation(epoch uint64) *precompute.Balance {
-	return ms.Balance
+func (s *ChainService) Participation(_ uint64) *precompute.Balance {
+	return s.Balance
 }

 // IsValidAttestation always returns true.
-func (ms *ChainService) IsValidAttestation(ctx context.Context, att *ethpb.Attestation) bool {
-	return ms.ValidAttestation
+func (s *ChainService) IsValidAttestation(_ context.Context, _ *ethpb.Attestation) bool {
+	return s.ValidAttestation
 }

 // IsCanonical returns and determines whether a block with the provided root is part of
 // the canonical chain.
-func (ms *ChainService) IsCanonical(ctx context.Context, blockRoot [32]byte) (bool, error) {
+func (s *ChainService) IsCanonical(_ context.Context, r [32]byte) (bool, error) {
+	if s.CanonicalRoots != nil {
+		_, ok := s.CanonicalRoots[r]
+		return ok, nil
+	}
 	return true, nil
 }

-// ClearCachedStates does nothing.
-func (ms *ChainService) ClearCachedStates() {}
-
 // HasInitSyncBlock mocks the same method in the chain service.
-func (ms *ChainService) HasInitSyncBlock(root [32]byte) bool {
+func (s *ChainService) HasInitSyncBlock(_ [32]byte) bool {
 	return false
 }

 // HeadGenesisValidatorRoot mocks HeadGenesisValidatorRoot method in chain service.
-func (ms *ChainService) HeadGenesisValidatorRoot() [32]byte {
+func (s *ChainService) HeadGenesisValidatorRoot() [32]byte {
 	return [32]byte{}
 }
+
+// VerifyBlkDescendant mocks VerifyBlkDescendant and always returns nil.
+func (s *ChainService) VerifyBlkDescendant(_ context.Context, _ [32]byte) error {
+	return s.VerifyBlkDescendantErr
+}
+
+// VerifyLmdFfgConsistency mocks VerifyLmdFfgConsistency and always returns nil.
+func (s *ChainService) VerifyLmdFfgConsistency(_ context.Context, a *ethpb.Attestation) error {
+	if !bytes.Equal(a.Data.BeaconBlockRoot, a.Data.Target.Root) {
+		return errors.New("LMD and FFG miss matched")
+	}
+	return nil
+}
+
+// VerifyFinalizedConsistency mocks VerifyFinalizedConsistency and always returns nil.
+func (s *ChainService) VerifyFinalizedConsistency(_ context.Context, r []byte) error {
+	if !bytes.Equal(r, s.FinalizedCheckPoint.Root) {
+		return errors.New("Root and finalized store are not consistent")
+	}
+	return nil
+}
+
+// ChainHeads mocks ChainHeads and always return nil.
+func (s *ChainService) ChainHeads() ([][32]byte, []types.Slot) {
+	return [][32]byte{
+			bytesutil.ToBytes32(bytesutil.PadTo([]byte("foo"), 32)),
+			bytesutil.ToBytes32(bytesutil.PadTo([]byte("bar"), 32)),
+		},
+		[]types.Slot{0, 1}
+}
--- a/beacon-chain/blockchain/weak_subjectivity_checks.go
+++ b/beacon-chain/blockchain/weak_subjectivity_checks.go
@@ -0,0 +1,60 @@
+package blockchain
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	"github.com/prysmaticlabs/prysm/beacon-chain/db/filters"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+)
+
+// VerifyWeakSubjectivityRoot verifies the weak subjectivity root in the service struct.
+// Reference design: https://github.com/ethereum/eth2.0-specs/blob/master/specs/phase0/weak-subjectivity.md#weak-subjectivity-sync-procedure
+func (s *Service) VerifyWeakSubjectivityRoot(ctx context.Context) error {
+	// TODO(7342): Remove the following to fully use weak subjectivity in production.
+	if s.cfg.WeakSubjectivityCheckpt == nil || len(s.cfg.WeakSubjectivityCheckpt.Root) == 0 || s.cfg.WeakSubjectivityCheckpt.Epoch == 0 {
+		return nil
+	}
+
+	// Do nothing if the weak subjectivity has previously been verified,
+	// or weak subjectivity epoch is higher than last finalized epoch.
+	if s.wsVerified {
+		return nil
+	}
+	if s.cfg.WeakSubjectivityCheckpt.Epoch > s.finalizedCheckpt.Epoch {
+		return nil
+	}
+
+	r := bytesutil.ToBytes32(s.cfg.WeakSubjectivityCheckpt.Root)
+	log.Infof("Performing weak subjectivity check for root %#x in epoch %d", r, s.cfg.WeakSubjectivityCheckpt.Epoch)
+	// Save initial sync cached blocks to DB.
+	if err := s.cfg.BeaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
+		return err
+	}
+	// A node should have the weak subjectivity block in the DB.
+	if !s.cfg.BeaconDB.HasBlock(ctx, r) {
+		return fmt.Errorf("node does not have root in DB: %#x", r)
+	}
+
+	startSlot, err := helpers.StartSlot(s.cfg.WeakSubjectivityCheckpt.Epoch)
+	if err != nil {
+		return err
+	}
+	// A node should have the weak subjectivity block corresponds to the correct epoch in the DB.
+	filter := filters.NewFilter().SetStartSlot(startSlot).SetEndSlot(startSlot + params.BeaconConfig().SlotsPerEpoch)
+	roots, err := s.cfg.BeaconDB.BlockRoots(ctx, filter)
+	if err != nil {
+		return err
+	}
+	for _, root := range roots {
+		if r == root {
+			log.Info("Weak subjectivity check has passed")
+			s.wsVerified = true
+			return nil
+		}
+	}
+
+	return fmt.Errorf("node does not have root in db corresponding to epoch: %#x %d", r, s.cfg.WeakSubjectivityCheckpt.Epoch)
+}
--- a/beacon-chain/blockchain/weak_subjectivity_checks_test.go
+++ b/beacon-chain/blockchain/weak_subjectivity_checks_test.go
@@ -0,0 +1,81 @@
+package blockchain
+
+import (
+	"context"
+	"testing"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
+	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+)
+
+func TestService_VerifyWeakSubjectivityRoot(t *testing.T) {
+	beaconDB := testDB.SetupDB(t)
+
+	b := testutil.NewBeaconBlock()
+	b.Block.Slot = 32
+	require.NoError(t, beaconDB.SaveBlock(context.Background(), b))
+	r, err := b.Block.HashTreeRoot()
+	require.NoError(t, err)
+	tests := []struct {
+		wsVerified     bool
+		wantErr        bool
+		checkpt        *ethpb.Checkpoint
+		finalizedEpoch types.Epoch
+		errString      string
+		name           string
+	}{
+		{
+			name:    "nil root and epoch",
+			wantErr: false,
+		},
+		{
+			name:           "already verified",
+			checkpt:        &ethpb.Checkpoint{Epoch: 2},
+			finalizedEpoch: 2,
+			wsVerified:     true,
+			wantErr:        false,
+		},
+		{
+			name:           "not yet to verify, ws epoch higher than finalized epoch",
+			checkpt:        &ethpb.Checkpoint{Epoch: 2},
+			finalizedEpoch: 1,
+			wantErr:        false,
+		},
+		{
+			name:           "can't find the block in DB",
+			checkpt:        &ethpb.Checkpoint{Root: bytesutil.PadTo([]byte{'a'}, 32), Epoch: 1},
+			finalizedEpoch: 3,
+			wantErr:        true,
+			errString:      "node does not have root in DB",
+		},
+		{
+			name:           "can't find the block corresponds to ws epoch in DB",
+			checkpt:        &ethpb.Checkpoint{Root: r[:], Epoch: 2}, // Root belongs in epoch 1.
+			finalizedEpoch: 3,
+			wantErr:        true,
+			errString:      "node does not have root in db corresponding to epoch",
+		},
+		{
+			name:           "can verify and pass",
+			checkpt:        &ethpb.Checkpoint{Root: r[:], Epoch: 1},
+			finalizedEpoch: 3,
+			wantErr:        false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			s := &Service{
+				cfg:              &Config{BeaconDB: beaconDB, WeakSubjectivityCheckpt: tt.checkpt},
+				wsVerified:       tt.wsVerified,
+				finalizedCheckpt: &ethpb.Checkpoint{Epoch: tt.finalizedEpoch},
+			}
+			if err := s.VerifyWeakSubjectivityRoot(context.Background()); (err != nil) != tt.wantErr {
+				require.ErrorContains(t, tt.errString, err)
+			}
+		})
+	}
+}
--- a/beacon-chain/cache/BUILD.bazel
+++ b/beacon-chain/cache/BUILD.bazel
@@ -1,19 +1,29 @@
 load("@prysm//tools/go:def.bzl", "go_library")
 load("@io_bazel_rules_go//go:def.bzl", "go_test")

+# gazelle:exclude committee_disabled.go
+# gazelle:exclude proposer_indices_disabled.go
 go_library(
    name = "go_default_library",
    srcs = [
        "attestation_data.go",
        "checkpoint_state.go",
-        "committee.go",
+        "committees.go",
        "common.go",
        "doc.go",
-        "hot_state_cache.go",
+        "proposer_indices_type.go",
        "skip_slot_cache.go",
-        "state_summary.go",
        "subnet_ids.go",
-    ],
+    ] + select({
+        "//fuzz:fuzzing_enabled": [
+            "committee_disabled.go",
+            "proposer_indices_disabled.go",
+        ],
+        "//conditions:default": [
+            "committee.go",
+            "proposer_indices.go",
+        ],
+    }),
    importpath = "github.com/prysmaticlabs/prysm/beacon-chain/cache",
    visibility = [
        "//beacon-chain:__subpackages__",
@@ -21,9 +31,8 @@ go_library(
        "//tools:__subpackages__",
    ],
    deps = [
-        "//beacon-chain/state:go_default_library",
-        "//proto/beacon/p2p/v1:go_default_library",
-        "//shared/featureconfig:go_default_library",
+        "//beacon-chain/state/interface:go_default_library",
+        "//beacon-chain/state/stateV0:go_default_library",
        "//shared/hashutil:go_default_library",
        "//shared/params:go_default_library",
        "//shared/sliceutil:go_default_library",
@@ -31,6 +40,7 @@ go_library(
        "@com_github_patrickmn_go_cache//:go_default_library",
        "@com_github_prometheus_client_golang//prometheus:go_default_library",
        "@com_github_prometheus_client_golang//prometheus/promauto:go_default_library",
+        "@com_github_prysmaticlabs_eth2_types//:go_default_library",
        "@com_github_prysmaticlabs_ethereumapis//eth/v1alpha1:go_default_library",
        "@io_k8s_client_go//tools/cache:go_default_library",
        "@io_opencensus_go//trace:go_default_library",
@@ -42,24 +52,26 @@ go_test(
    size = "small",
    srcs = [
        "attestation_data_test.go",
+        "cache_test.go",
        "checkpoint_state_test.go",
        "committee_fuzz_test.go",
        "committee_test.go",
-        "feature_flag_test.go",
-        "hot_state_cache_test.go",
+        "proposer_indices_test.go",
        "skip_slot_cache_test.go",
        "subnet_ids_test.go",
    ],
    embed = [":go_default_library"],
    deps = [
-        "//beacon-chain/state:go_default_library",
+        "//beacon-chain/state/interface:go_default_library",
+        "//beacon-chain/state/stateV0:go_default_library",
        "//proto/beacon/p2p/v1:go_default_library",
        "//shared/bytesutil:go_default_library",
-        "//shared/featureconfig:go_default_library",
-        "//shared/hashutil:go_default_library",
        "//shared/params:go_default_library",
+        "//shared/testutil/assert:go_default_library",
+        "//shared/testutil/require:go_default_library",
        "@com_github_gogo_protobuf//proto:go_default_library",
        "@com_github_google_gofuzz//:go_default_library",
+        "@com_github_prysmaticlabs_eth2_types//:go_default_library",
        "@com_github_prysmaticlabs_ethereumapis//eth/v1alpha1:go_default_library",
    ],
 )
--- a/beacon-chain/cache/attestation_data.go
+++ b/beacon-chain/cache/attestation_data.go
@@ -11,8 +11,7 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/shared/featureconfig"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateV0"
 	"k8s.io/client-go/tools/cache"
 )

@@ -99,10 +98,7 @@ func (c *AttestationCache) Get(ctx context.Context, req *ethpb.AttestationDataRe

 	if exists && item != nil && item.(*attestationReqResWrapper).res != nil {
 		attestationCacheHit.Inc()
-		if featureconfig.Get().ReduceAttesterStateCopy {
-			return state.CopyAttestationData(item.(*attestationReqResWrapper).res), nil
-		}
-		return item.(*attestationReqResWrapper).res, nil
+		return stateV0.CopyAttestationData(item.(*attestationReqResWrapper).res), nil
 	}
 	attestationCacheMiss.Inc()
 	return nil, nil
@@ -138,7 +134,7 @@ func (c *AttestationCache) MarkNotInProgress(req *ethpb.AttestationDataRequest)
 }

 // Put the response in the cache.
-func (c *AttestationCache) Put(ctx context.Context, req *ethpb.AttestationDataRequest, res *ethpb.AttestationData) error {
+func (c *AttestationCache) Put(_ context.Context, req *ethpb.AttestationDataRequest, res *ethpb.AttestationData) error {
 	data := &attestationReqResWrapper{
 		req,
 		res,
@@ -167,10 +163,7 @@ func wrapperToKey(i interface{}) (string, error) {
 }

 func reqToKey(req *ethpb.AttestationDataRequest) (string, error) {
-	if featureconfig.Get().ReduceAttesterStateCopy {
-		return fmt.Sprintf("%d", req.Slot), nil
-	}
-	return fmt.Sprintf("%d-%d", req.CommitteeIndex, req.Slot), nil
+	return fmt.Sprintf("%d", req.Slot), nil
 }

 type attestationReqResWrapper struct {
--- a/beacon-chain/cache/attestation_data_test.go
+++ b/beacon-chain/cache/attestation_data_test.go
@@ -7,6 +7,7 @@ import (
 	"github.com/gogo/protobuf/proto"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/cache"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
 )

 func TestAttestationCache_RoundTrip(t *testing.T) {
@@ -19,34 +20,20 @@ func TestAttestationCache_RoundTrip(t *testing.T) {
 	}

 	response, err := c.Get(ctx, req)
-	if err != nil {
-		t.Error(err)
-	}
+	assert.NoError(t, err)
+	assert.Equal(t, (*ethpb.AttestationData)(nil), response)

-	if response != nil {
-		t.Errorf("Empty cache returned an object: %v", response)
-	}
-
-	if err := c.MarkInProgress(req); err != nil {
-		t.Error(err)
-	}
+	assert.NoError(t, c.MarkInProgress(req))

 	res := &ethpb.AttestationData{
-		Target: &ethpb.Checkpoint{Epoch: 5},
+		Target: &ethpb.Checkpoint{Epoch: 5, Root: make([]byte, 32)},
 	}

-	if err = c.Put(ctx, req, res); err != nil {
-		t.Error(err)
-	}
-
-	if err := c.MarkNotInProgress(req); err != nil {
-		t.Error(err)
-	}
+	assert.NoError(t, c.Put(ctx, req, res))
+	assert.NoError(t, c.MarkNotInProgress(req))

 	response, err = c.Get(ctx, req)
-	if err != nil {
-		t.Error(err)
-	}
+	assert.NoError(t, err)

 	if !proto.Equal(response, res) {
 		t.Error("Expected equal protos to return from cache")
--- a/beacon-chain/cache/cache_test.go
+++ b/beacon-chain/cache/cache_test.go
@@ -0,0 +1,9 @@
+package cache
+
+import (
+	"testing"
+)
+
+func TestMain(m *testing.M) {
+	m.Run()
+}
--- a/beacon-chain/cache/checkpoint_state.go
+++ b/beacon-chain/cache/checkpoint_state.go
@@ -1,30 +1,25 @@
 package cache

 import (
-	"errors"
 	"sync"

+	lru "github.com/hashicorp/golang-lru"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
 	"github.com/prysmaticlabs/prysm/shared/hashutil"
-	"k8s.io/client-go/tools/cache"
 )

 var (
-	// ErrNotCheckpointState will be returned when a cache object is not a pointer to
-	// a CheckpointState struct.
-	ErrNotCheckpointState = errors.New("object is not a state by check point struct")
-
 	// maxCheckpointStateSize defines the max number of entries check point to state cache can contain.
 	// Choosing 10 to account for multiple forks, this allows 5 forks per epoch boundary with 2 epochs
 	// window to accept attestation based on latest spec.
-	maxCheckpointStateSize = uint64(10)
+	maxCheckpointStateSize = 10

 	// Metrics.
 	checkpointStateMiss = promauto.NewCounter(prometheus.CounterOpts{
-		Name: "check_point_statecache_miss",
+		Name: "check_point_state_cache_miss",
 		Help: "The number of check point state requests that aren't present in the cache.",
 	})
 	checkpointStateHit = promauto.NewCounter(prometheus.CounterOpts{
@@ -33,42 +28,26 @@ var (
 	})
 )

-// CheckpointState defines the active validator indices per epoch.
-type CheckpointState struct {
-	Checkpoint *ethpb.Checkpoint
-	State      *stateTrie.BeaconState
-}
-
 // CheckpointStateCache is a struct with 1 queue for looking up state by checkpoint.
 type CheckpointStateCache struct {
-	cache *cache.FIFO
+	cache *lru.Cache
 	lock  sync.RWMutex
 }

-// checkpointState takes the checkpoint as the key of the resulting state.
-func checkpointState(obj interface{}) (string, error) {
-	info, ok := obj.(*CheckpointState)
-	if !ok {
-		return "", ErrNotCheckpointState
-	}
-
-	h, err := hashutil.HashProto(info.Checkpoint)
-	if err != nil {
-		return "", err
-	}
-	return string(h[:]), nil
-}
-
 // NewCheckpointStateCache creates a new checkpoint state cache for storing/accessing processed state.
 func NewCheckpointStateCache() *CheckpointStateCache {
+	cache, err := lru.New(maxCheckpointStateSize)
+	if err != nil {
+		panic(err)
+	}
 	return &CheckpointStateCache{
-		cache: cache.NewFIFO(checkpointState),
+		cache: cache,
 	}
 }

 // StateByCheckpoint fetches state by checkpoint. Returns true with a
 // reference to the CheckpointState info, if exists. Otherwise returns false, nil.
-func (c *CheckpointStateCache) StateByCheckpoint(cp *ethpb.Checkpoint) (*stateTrie.BeaconState, error) {
+func (c *CheckpointStateCache) StateByCheckpoint(cp *ethpb.Checkpoint) (iface.BeaconState, error) {
 	c.lock.RLock()
 	defer c.lock.RUnlock()
 	h, err := hashutil.HashProto(cp)
@@ -76,44 +55,27 @@ func (c *CheckpointStateCache) StateByCheckpoint(cp *ethpb.Checkpoint) (*stateTr
 		return nil, err
 	}

-	obj, exists, err := c.cache.GetByKey(string(h[:]))
-	if err != nil {
-		return nil, err
-	}
+	item, exists := c.cache.Get(h)

-	if exists {
+	if exists && item != nil {
 		checkpointStateHit.Inc()
-	} else {
-		checkpointStateMiss.Inc()
-		return nil, nil
+		// Copy here is unnecessary since the return will only be used to verify attestation signature.
+		return item.(iface.BeaconState), nil
 	}

-	info, ok := obj.(*CheckpointState)
-	if !ok {
-		return nil, ErrNotCheckpointState
-	}
-
-	// Copy here is unnecessary since the return will only be used to verify attestation signature.
-	return info.State, nil
+	checkpointStateMiss.Inc()
+	return nil, nil
 }

 // AddCheckpointState adds CheckpointState object to the cache. This method also trims the least
 // recently added CheckpointState object if the cache size has ready the max cache size limit.
-func (c *CheckpointStateCache) AddCheckpointState(cp *CheckpointState) error {
+func (c *CheckpointStateCache) AddCheckpointState(cp *ethpb.Checkpoint, s iface.ReadOnlyBeaconState) error {
 	c.lock.Lock()
 	defer c.lock.Unlock()
-	if err := c.cache.AddIfNotPresent(&CheckpointState{
-		Checkpoint: stateTrie.CopyCheckpoint(cp.Checkpoint),
-		State:      cp.State.Copy(),
-	}); err != nil {
+	h, err := hashutil.HashProto(cp)
+	if err != nil {
 		return err
 	}
-
-	trim(c.cache, maxCheckpointStateSize)
+	c.cache.Add(h, s)
 	return nil
 }
-
-// CheckpointStateKeys returns the keys of the state in cache.
-func (c *CheckpointStateCache) CheckpointStateKeys() []string {
-	return c.cache.ListKeys()
-}
--- a/beacon-chain/cache/checkpoint_state_test.go
+++ b/beacon-chain/cache/checkpoint_state_test.go
@@ -1,141 +1,74 @@
 package cache

 import (
-	"reflect"
 	"testing"

 	"github.com/gogo/protobuf/proto"
+	types "github.com/prysmaticlabs/eth2-types"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateV0"
 	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
-	"github.com/prysmaticlabs/prysm/shared/hashutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 )

-func TestCheckpointStateCacheKeyFn_OK(t *testing.T) {
-	cp := &ethpb.Checkpoint{Epoch: 1, Root: bytesutil.PadTo([]byte{'A'}, 32)}
-	st, err := stateTrie.InitializeFromProto(&pb.BeaconState{
-		Slot: 64,
-	})
-	if err != nil {
-		t.Fatal(err)
-	}
-	info := &CheckpointState{
-		Checkpoint: cp,
-		State:      st,
-	}
-	key, err := checkpointState(info)
-	if err != nil {
-		t.Fatal(err)
-	}
-	wantedKey, err := hashutil.HashProto(cp)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if key != string(wantedKey[:]) {
-		t.Errorf("Incorrect hash key: %s, expected %s", key, string(wantedKey[:]))
-	}
-}
-
-func TestCheckpointStateCacheKeyFn_InvalidObj(t *testing.T) {
-	_, err := checkpointState("bad")
-	if err != ErrNotCheckpointState {
-		t.Errorf("Expected error %v, got %v", ErrNotCheckpointState, err)
-	}
-}
-
 func TestCheckpointStateCache_StateByCheckpoint(t *testing.T) {
 	cache := NewCheckpointStateCache()

 	cp1 := &ethpb.Checkpoint{Epoch: 1, Root: bytesutil.PadTo([]byte{'A'}, 32)}
-	st, err := stateTrie.InitializeFromProto(&pb.BeaconState{
+	st, err := stateV0.InitializeFromProto(&pb.BeaconState{
 		GenesisValidatorsRoot: params.BeaconConfig().ZeroHash[:],
 		Slot:                  64,
 	})
-	if err != nil {
-		t.Fatal(err)
-	}
-	info1 := &CheckpointState{
-		Checkpoint: cp1,
-		State:      st,
-	}
-	state, err := cache.StateByCheckpoint(cp1)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if state != nil {
-		t.Error("Expected state not to exist in empty cache")
-	}
+	require.NoError(t, err)
+
+	state, err := cache.StateByCheckpoint(cp1)
+	require.NoError(t, err)
+	assert.Equal(t, iface.BeaconState(nil), state, "Expected state not to exist in empty cache")
+
+	require.NoError(t, cache.AddCheckpointState(cp1, st))

-	if err := cache.AddCheckpointState(info1); err != nil {
-		t.Fatal(err)
-	}
 	state, err = cache.StateByCheckpoint(cp1)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !proto.Equal(state.InnerStateUnsafe(), info1.State.InnerStateUnsafe()) {
+	require.NoError(t, err)
+
+	pbState1, err := stateV0.ProtobufBeaconState(state.InnerStateUnsafe())
+	require.NoError(t, err)
+	pbState2, err := stateV0.ProtobufBeaconState(st.InnerStateUnsafe())
+	require.NoError(t, err)
+	if !proto.Equal(pbState1, pbState2) {
 		t.Error("incorrectly cached state")
 	}

 	cp2 := &ethpb.Checkpoint{Epoch: 2, Root: bytesutil.PadTo([]byte{'B'}, 32)}
-	st2, err := stateTrie.InitializeFromProto(&pb.BeaconState{
+	st2, err := stateV0.InitializeFromProto(&pb.BeaconState{
 		Slot: 128,
 	})
-	if err != nil {
-		t.Fatal(err)
-	}
-	info2 := &CheckpointState{
-		Checkpoint: cp2,
-		State:      st2,
-	}
-	if err := cache.AddCheckpointState(info2); err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
+	require.NoError(t, cache.AddCheckpointState(cp2, st2))
+
 	state, err = cache.StateByCheckpoint(cp2)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !reflect.DeepEqual(state.CloneInnerState(), info2.State.CloneInnerState()) {
-		t.Error("incorrectly cached state")
-	}
+	require.NoError(t, err)
+	assert.DeepEqual(t, st2.CloneInnerState(), state.CloneInnerState(), "incorrectly cached state")

 	state, err = cache.StateByCheckpoint(cp1)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !reflect.DeepEqual(state.CloneInnerState(), info1.State.CloneInnerState()) {
-		t.Error("incorrectly cached state")
-	}
+	require.NoError(t, err)
+	assert.DeepEqual(t, st.CloneInnerState(), state.CloneInnerState(), "incorrectly cached state")
 }

 func TestCheckpointStateCache_MaxSize(t *testing.T) {
 	c := NewCheckpointStateCache()
-	st, err := stateTrie.InitializeFromProto(&pb.BeaconState{
+	st, err := stateV0.InitializeFromProto(&pb.BeaconState{
 		Slot: 0,
 	})
-	if err != nil {
-		t.Fatal(err)
-	}
-	for i := uint64(0); i < maxCheckpointStateSize+100; i++ {
-		if err := st.SetSlot(i); err != nil {
-			t.Fatal(err)
-		}
-		info := &CheckpointState{
-			Checkpoint: &ethpb.Checkpoint{Epoch: i},
-			State:      st,
-		}
-		if err := c.AddCheckpointState(info); err != nil {
-			t.Fatal(err)
-		}
+	require.NoError(t, err)
+
+	for i := uint64(0); i < uint64(maxCheckpointStateSize+100); i++ {
+		require.NoError(t, st.SetSlot(types.Slot(i)))
+		require.NoError(t, c.AddCheckpointState(&ethpb.Checkpoint{Epoch: types.Epoch(i), Root: make([]byte, 32)}, st))
 	}

-	if uint64(len(c.cache.ListKeys())) != maxCheckpointStateSize {
-		t.Errorf(
-			"Expected hash cache key size to be %d, got %d",
-			maxCheckpointStateSize,
-			len(c.cache.ListKeys()),
-		)
-	}
+	assert.Equal(t, maxCheckpointStateSize, len(c.cache.Keys()))
 }
--- a/beacon-chain/cache/committee.go
+++ b/beacon-chain/cache/committee.go
@@ -1,3 +1,5 @@
+// +build !libfuzzer
+
 package cache

 import (
@@ -6,20 +8,16 @@ import (

 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
+	types "github.com/prysmaticlabs/eth2-types"
 	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/prysmaticlabs/prysm/shared/sliceutil"
 	"k8s.io/client-go/tools/cache"
 )

 var (
-	// ErrNotCommittee will be returned when a cache object is not a pointer to
-	// a Committee struct.
-	ErrNotCommittee = errors.New("object is not a committee struct")
-
 	// maxCommitteesCacheSize defines the max number of shuffled committees on per randao basis can cache.
-	// Due to reorgs, it's good to keep the old cache around for quickly switch over. 10 is a generous
-	// cache size as it considers 3 concurrent branches over 3 epochs.
-	maxCommitteesCacheSize = uint64(10)
+	// Due to reorgs and long finality, it's good to keep the old cache around for quickly switch over.
+	maxCommitteesCacheSize = uint64(32)

 	// CommitteeCacheMiss tracks the number of committee requests that aren't present in the cache.
 	CommitteeCacheMiss = promauto.NewCounter(prometheus.CounterOpts{
@@ -33,15 +31,6 @@ var (
 	})
 )

-// Committees defines the shuffled committees seed.
-type Committees struct {
-	CommitteeCount  uint64
-	Seed            [32]byte
-	ShuffledIndices []uint64
-	SortedIndices   []uint64
-	ProposerIndices []uint64
-}
-
 // CommitteeCache is a struct with 1 queue for looking up shuffled indices list by seed.
 type CommitteeCache struct {
 	CommitteeCache *cache.FIFO
@@ -67,7 +56,7 @@ func NewCommitteesCache() *CommitteeCache {

 // Committee fetches the shuffled indices by slot and committee index. Every list of indices
 // represent one committee. Returns true if the list exists with slot and committee index. Otherwise returns false, nil.
-func (c *CommitteeCache) Committee(slot uint64, seed [32]byte, index uint64) ([]uint64, error) {
+func (c *CommitteeCache) Committee(slot types.Slot, seed [32]byte, index types.CommitteeIndex) ([]types.ValidatorIndex, error) {
 	c.lock.RLock()
 	defer c.lock.RUnlock()

@@ -89,11 +78,11 @@ func (c *CommitteeCache) Committee(slot uint64, seed [32]byte, index uint64) ([]
 	}

 	committeeCountPerSlot := uint64(1)
-	if item.CommitteeCount/params.BeaconConfig().SlotsPerEpoch > 1 {
-		committeeCountPerSlot = item.CommitteeCount / params.BeaconConfig().SlotsPerEpoch
+	if item.CommitteeCount/uint64(params.BeaconConfig().SlotsPerEpoch) > 1 {
+		committeeCountPerSlot = item.CommitteeCount / uint64(params.BeaconConfig().SlotsPerEpoch)
 	}

-	indexOffSet := index + (slot%params.BeaconConfig().SlotsPerEpoch)*committeeCountPerSlot
+	indexOffSet := uint64(index) + uint64(slot.ModSlot(params.BeaconConfig().SlotsPerEpoch).Mul(committeeCountPerSlot))
 	start, end := startEndIndices(item, indexOffSet)

 	if end > uint64(len(item.ShuffledIndices)) || end < start {
@@ -116,37 +105,8 @@ func (c *CommitteeCache) AddCommitteeShuffledList(committees *Committees) error
 	return nil
 }

-// AddProposerIndicesList updates the committee shuffled list with proposer indices.
-func (c *CommitteeCache) AddProposerIndicesList(seed [32]byte, indices []uint64) error {
-	c.lock.Lock()
-	defer c.lock.Unlock()
-
-	obj, exists, err := c.CommitteeCache.GetByKey(key(seed))
-	if err != nil {
-		return err
-	}
-	if !exists {
-		committees := &Committees{ProposerIndices: indices}
-		if err := c.CommitteeCache.Add(committees); err != nil {
-			return err
-		}
-	} else {
-		committees, ok := obj.(*Committees)
-		if !ok {
-			return ErrNotCommittee
-		}
-		committees.ProposerIndices = indices
-		if err := c.CommitteeCache.Add(committees); err != nil {
-			return err
-		}
-	}
-
-	trim(c.CommitteeCache, maxCommitteesCacheSize)
-	return nil
-}
-
 // ActiveIndices returns the active indices of a given seed stored in cache.
-func (c *CommitteeCache) ActiveIndices(seed [32]byte) ([]uint64, error) {
+func (c *CommitteeCache) ActiveIndices(seed [32]byte) ([]types.ValidatorIndex, error) {
 	c.lock.RLock()
 	defer c.lock.RUnlock()
 	obj, exists, err := c.CommitteeCache.GetByKey(key(seed))
@@ -193,28 +153,10 @@ func (c *CommitteeCache) ActiveIndicesCount(seed [32]byte) (int, error) {
 	return len(item.SortedIndices), nil
 }

-// ProposerIndices returns the proposer indices of a given seed.
-func (c *CommitteeCache) ProposerIndices(seed [32]byte) ([]uint64, error) {
-	c.lock.RLock()
-	defer c.lock.RUnlock()
-	obj, exists, err := c.CommitteeCache.GetByKey(key(seed))
-	if err != nil {
-		return nil, err
-	}
-
-	if exists {
-		CommitteeCacheHit.Inc()
-	} else {
-		CommitteeCacheMiss.Inc()
-		return nil, nil
-	}
-
-	item, ok := obj.(*Committees)
-	if !ok {
-		return nil, ErrNotCommittee
-	}
-
-	return item.ProposerIndices, nil
+// HasEntry returns true if the committee cache has a value.
+func (c *CommitteeCache) HasEntry(seed string) bool {
+	_, ok, err := c.CommitteeCache.GetByKey(seed)
+	return err == nil && ok
 }

 func startEndIndices(c *Committees, index uint64) (uint64, uint64) {
--- a/beacon-chain/cache/committee_disabled.go
+++ b/beacon-chain/cache/committee_disabled.go
@@ -0,0 +1,52 @@
+// +build libfuzzer
+
+// This file is used in fuzzer builds to bypass global committee caches.
+package cache
+
+import types "github.com/prysmaticlabs/eth2-types"
+
+// FakeCommitteeCache is a struct with 1 queue for looking up shuffled indices list by seed.
+type FakeCommitteeCache struct {
+}
+
+// NewCommitteesCache creates a new committee cache for storing/accessing shuffled indices of a committee.
+func NewCommitteesCache() *FakeCommitteeCache {
+	return &FakeCommitteeCache{}
+}
+
+// Committee fetches the shuffled indices by slot and committee index. Every list of indices
+// represent one committee. Returns true if the list exists with slot and committee index. Otherwise returns false, nil.
+func (c *FakeCommitteeCache) Committee(slot types.Slot, seed [32]byte, index types.CommitteeIndex) ([]types.ValidatorIndex, error) {
+	return nil, nil
+}
+
+// AddCommitteeShuffledList adds Committee shuffled list object to the cache. T
+// his method also trims the least recently list if the cache size has ready the max cache size limit.
+func (c *FakeCommitteeCache) AddCommitteeShuffledList(committees *Committees) error {
+	return nil
+}
+
+// AddProposerIndicesList updates the committee shuffled list with proposer indices.
+func (c *FakeCommitteeCache) AddProposerIndicesList(seed [32]byte, indices []types.ValidatorIndex) error {
+	return nil
+}
+
+// ActiveIndices returns the active indices of a given seed stored in cache.
+func (c *FakeCommitteeCache) ActiveIndices(seed [32]byte) ([]types.ValidatorIndex, error) {
+	return nil, nil
+}
+
+// ActiveIndicesCount returns the active indices count of a given seed stored in cache.
+func (c *FakeCommitteeCache) ActiveIndicesCount(seed [32]byte) (int, error) {
+	return 0, nil
+}
+
+// ProposerIndices returns the proposer indices of a given seed.
+func (c *FakeCommitteeCache) ProposerIndices(seed [32]byte) ([]types.ValidatorIndex, error) {
+	return nil, nil
+}
+
+// HasEntry returns true if the committee cache has a value.
+func (c *FakeCommitteeCache) HasEntry(string) bool {
+	return false
+}
--- a/beacon-chain/cache/committee_fuzz_test.go
+++ b/beacon-chain/cache/committee_fuzz_test.go
@@ -1,10 +1,11 @@
 package cache

 import (
-	"reflect"
 	"testing"

 	fuzz "github.com/google/gofuzz"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 )

 func TestCommitteeKeyFuzz_OK(t *testing.T) {
@@ -14,12 +15,8 @@ func TestCommitteeKeyFuzz_OK(t *testing.T) {
 	for i := 0; i < 100000; i++ {
 		fuzzer.Fuzz(c)
 		k, err := committeeKeyFn(c)
-		if err != nil {
-			t.Fatal(err)
-		}
-		if k != key(c.Seed) {
-			t.Errorf("Incorrect hash k: %s, expected %s", k, key(c.Seed))
-		}
+		require.NoError(t, err)
+		assert.Equal(t, key(c.Seed), k)
 	}
 }

@@ -30,17 +27,12 @@ func TestCommitteeCache_FuzzCommitteesByEpoch(t *testing.T) {

 	for i := 0; i < 100000; i++ {
 		fuzzer.Fuzz(c)
-		if err := cache.AddCommitteeShuffledList(c); err != nil {
-			t.Fatal(err)
-		}
-		if _, err := cache.Committee(0, c.Seed, 0); err != nil {
-			t.Fatal(err)
-		}
+		require.NoError(t, cache.AddCommitteeShuffledList(c))
+		_, err := cache.Committee(0, c.Seed, 0)
+		require.NoError(t, err)
 	}

-	if uint64(len(cache.CommitteeCache.ListKeys())) != maxCommitteesCacheSize {
-		t.Error("Incorrect key size")
-	}
+	assert.Equal(t, maxCommitteesCacheSize, uint64(len(cache.CommitteeCache.ListKeys())), "Incorrect key size")
 }

 func TestCommitteeCache_FuzzActiveIndices(t *testing.T) {
@@ -50,19 +42,12 @@ func TestCommitteeCache_FuzzActiveIndices(t *testing.T) {

 	for i := 0; i < 100000; i++ {
 		fuzzer.Fuzz(c)
-		if err := cache.AddCommitteeShuffledList(c); err != nil {
-			t.Fatal(err)
-		}
+		require.NoError(t, cache.AddCommitteeShuffledList(c))
+
 		indices, err := cache.ActiveIndices(c.Seed)
-		if err != nil {
-			t.Fatal(err)
-		}
-		if !reflect.DeepEqual(indices, c.SortedIndices) {
-			t.Error("Saved indices not the same")
-		}
+		require.NoError(t, err)
+		assert.DeepEqual(t, c.SortedIndices, indices)
 	}

-	if uint64(len(cache.CommitteeCache.ListKeys())) != maxCommitteesCacheSize {
-		t.Error("Incorrect key size")
-	}
+	assert.Equal(t, maxCommitteesCacheSize, uint64(len(cache.CommitteeCache.ListKeys())), "Incorrect key size")
 }
--- a/beacon-chain/cache/committee_test.go
+++ b/beacon-chain/cache/committee_test.go
@@ -2,201 +2,116 @@ package cache

 import (
 	"math"
-	"reflect"
 	"sort"
 	"strconv"
 	"testing"

+	types "github.com/prysmaticlabs/eth2-types"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 )

 func TestCommitteeKeyFn_OK(t *testing.T) {
 	item := &Committees{
 		CommitteeCount:  1,
 		Seed:            [32]byte{'A'},
-		ShuffledIndices: []uint64{1, 2, 3, 4, 5},
+		ShuffledIndices: []types.ValidatorIndex{1, 2, 3, 4, 5},
 	}

 	k, err := committeeKeyFn(item)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if k != key(item.Seed) {
-		t.Errorf("Incorrect hash k: %s, expected %s", k, key(item.Seed))
-	}
+	require.NoError(t, err)
+	assert.Equal(t, key(item.Seed), k)
 }

 func TestCommitteeKeyFn_InvalidObj(t *testing.T) {
 	_, err := committeeKeyFn("bad")
-	if err != ErrNotCommittee {
-		t.Errorf("Expected error %v, got %v", ErrNotCommittee, err)
-	}
+	assert.Equal(t, ErrNotCommittee, err)
 }

 func TestCommitteeCache_CommitteesByEpoch(t *testing.T) {
 	cache := NewCommitteesCache()

 	item := &Committees{
-		ShuffledIndices: []uint64{1, 2, 3, 4, 5, 6},
+		ShuffledIndices: []types.ValidatorIndex{1, 2, 3, 4, 5, 6},
 		Seed:            [32]byte{'A'},
 		CommitteeCount:  3,
 	}

 	slot := params.BeaconConfig().SlotsPerEpoch
-	committeeIndex := uint64(1)
+	committeeIndex := types.CommitteeIndex(1)
 	indices, err := cache.Committee(slot, item.Seed, committeeIndex)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 	if indices != nil {
 		t.Error("Expected committee not to exist in empty cache")
 	}
+	require.NoError(t, cache.AddCommitteeShuffledList(item))

-	if err := cache.AddCommitteeShuffledList(item); err != nil {
-		t.Fatal(err)
-	}
-	wantedIndex := uint64(0)
+	wantedIndex := types.CommitteeIndex(0)
 	indices, err = cache.Committee(slot, item.Seed, wantedIndex)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)

-	start, end := startEndIndices(item, wantedIndex)
-	if !reflect.DeepEqual(indices, item.ShuffledIndices[start:end]) {
-		t.Errorf(
-			"Expected fetched active indices to be %v, got %v",
-			indices,
-			item.ShuffledIndices[start:end],
-		)
-	}
+	start, end := startEndIndices(item, uint64(wantedIndex))
+	assert.DeepEqual(t, item.ShuffledIndices[start:end], indices)
 }

 func TestCommitteeCache_ActiveIndices(t *testing.T) {
 	cache := NewCommitteesCache()

-	item := &Committees{Seed: [32]byte{'A'}, SortedIndices: []uint64{1, 2, 3, 4, 5, 6}}
+	item := &Committees{Seed: [32]byte{'A'}, SortedIndices: []types.ValidatorIndex{1, 2, 3, 4, 5, 6}}
 	indices, err := cache.ActiveIndices(item.Seed)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 	if indices != nil {
-		t.Error("Expected committee count not to exist in empty cache")
+		t.Error("Expected committee not to exist in empty cache")
 	}

-	if err := cache.AddCommitteeShuffledList(item); err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, cache.AddCommitteeShuffledList(item))

 	indices, err = cache.ActiveIndices(item.Seed)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !reflect.DeepEqual(indices, item.SortedIndices) {
-		t.Error("Did not receive correct active indices from cache")
-	}
+	require.NoError(t, err)
+	assert.DeepEqual(t, item.SortedIndices, indices)
 }

 func TestCommitteeCache_ActiveCount(t *testing.T) {
 	cache := NewCommitteesCache()

-	item := &Committees{Seed: [32]byte{'A'}, SortedIndices: []uint64{1, 2, 3, 4, 5, 6}}
+	item := &Committees{Seed: [32]byte{'A'}, SortedIndices: []types.ValidatorIndex{1, 2, 3, 4, 5, 6}}
 	count, err := cache.ActiveIndicesCount(item.Seed)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if count != 0 {
-		t.Error("Expected active count not to exist in empty cache")
-	}
+	require.NoError(t, err)
+	assert.Equal(t, 0, count, "Expected active count not to exist in empty cache")

-	if err := cache.AddCommitteeShuffledList(item); err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, cache.AddCommitteeShuffledList(item))

 	count, err = cache.ActiveIndicesCount(item.Seed)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if count != len(item.SortedIndices) {
-		t.Error("Did not receive correct active acount from cache")
-	}
-}
-
-func TestCommitteeCache_AddProposerIndicesList(t *testing.T) {
-	cache := NewCommitteesCache()
-
-	seed := [32]byte{'A'}
-	indices := []uint64{1, 2, 3, 4, 5}
-	indices, err := cache.ProposerIndices(seed)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if indices != nil {
-		t.Error("Expected committee count not to exist in empty cache")
-	}
-	if err := cache.AddProposerIndicesList(seed, indices); err != nil {
-		t.Fatal(err)
-	}
-	received, err := cache.ProposerIndices(seed)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !reflect.DeepEqual(indices, received) {
-		t.Error("Did not receive correct proposer indices from cache")
-	}
-
-	item := &Committees{Seed: [32]byte{'B'}, SortedIndices: []uint64{1, 2, 3, 4, 5, 6}}
-	if err := cache.AddCommitteeShuffledList(item); err != nil {
-		t.Fatal(err)
-	}
-	indices, err = cache.ProposerIndices(item.Seed)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if indices != nil {
-		t.Error("Expected committee count not to exist in empty cache")
-	}
-	if err := cache.AddProposerIndicesList(item.Seed, indices); err != nil {
-		t.Fatal(err)
-	}
-	received, err = cache.ProposerIndices(item.Seed)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !reflect.DeepEqual(indices, received) {
-		t.Error("Did not receive correct proposer indices from cache")
-	}
-
+	require.NoError(t, err)
+	assert.Equal(t, len(item.SortedIndices), count)
 }

 func TestCommitteeCache_CanRotate(t *testing.T) {
 	cache := NewCommitteesCache()

 	// Should rotate out all the epochs except 190 through 199.
-	for i := 100; i < 200; i++ {
+	start := 100
+	end := 200
+	for i := start; i < end; i++ {
 		s := []byte(strconv.Itoa(i))
 		item := &Committees{Seed: bytesutil.ToBytes32(s)}
-		if err := cache.AddCommitteeShuffledList(item); err != nil {
-			t.Fatal(err)
-		}
+		require.NoError(t, cache.AddCommitteeShuffledList(item))
 	}

 	k := cache.CommitteeCache.ListKeys()
-	if uint64(len(k)) != maxCommitteesCacheSize {
-		t.Errorf("wanted: %d, got: %d", maxCommitteesCacheSize, len(k))
-	}
+	assert.Equal(t, maxCommitteesCacheSize, uint64(len(k)))

 	sort.Slice(k, func(i, j int) bool {
 		return k[i] < k[j]
 	})
-	s := bytesutil.ToBytes32([]byte(strconv.Itoa(190)))
-	if k[0] != key(s) {
-		t.Error("incorrect key received for slot 190")
-	}
+	wanted := end - int(maxCommitteesCacheSize)
+	s := bytesutil.ToBytes32([]byte(strconv.Itoa(wanted)))
+	assert.Equal(t, key(s), k[0], "incorrect key received for slot 190")
+
 	s = bytesutil.ToBytes32([]byte(strconv.Itoa(199)))
-	if k[len(k)-1] != key(s) {
-		t.Error("incorrect key received for slot 199")
-	}
+	assert.Equal(t, key(s), k[len(k)-1], "incorrect key received for slot 199")
 }

 func TestCommitteeCacheOutOfRange(t *testing.T) {
@@ -205,15 +120,11 @@ func TestCommitteeCacheOutOfRange(t *testing.T) {
 	err := cache.CommitteeCache.Add(&Committees{
 		CommitteeCount:  1,
 		Seed:            seed,
-		ShuffledIndices: []uint64{0},
-		SortedIndices:   []uint64{},
-		ProposerIndices: []uint64{},
+		ShuffledIndices: []types.ValidatorIndex{0},
+		SortedIndices:   []types.ValidatorIndex{},
 	})
-	if err != nil {
-		t.Error(err)
-	}
+	require.NoError(t, err)
+
 	_, err = cache.Committee(0, seed, math.MaxUint64) // Overflow!
-	if err == nil {
-		t.Fatal("Did not fail as expected")
-	}
+	require.NotNil(t, err, "Did not fail as expected")
 }
--- a/beacon-chain/cache/committees.go
+++ b/beacon-chain/cache/committees.go
@@ -0,0 +1,19 @@
+package cache
+
+import (
+	"errors"
+
+	types "github.com/prysmaticlabs/eth2-types"
+)
+
+// ErrNotCommittee will be returned when a cache object is not a pointer to
+// a Committee struct.
+var ErrNotCommittee = errors.New("object is not a committee struct")
+
+// Committees defines the shuffled committees seed.
+type Committees struct {
+	CommitteeCount  uint64
+	Seed            [32]byte
+	ShuffledIndices []types.ValidatorIndex
+	SortedIndices   []types.ValidatorIndex
+}
--- a/beacon-chain/cache/common.go
+++ b/beacon-chain/cache/common.go
@@ -8,7 +8,7 @@ import (
 var (
 	// maxCacheSize is 4x of the epoch length for additional cache padding.
 	// Requests should be only accessing committees within defined epoch length.
-	maxCacheSize = 4 * params.BeaconConfig().SlotsPerEpoch
+	maxCacheSize = uint64(4 * params.BeaconConfig().SlotsPerEpoch)
 )

 // trim the FIFO queue to the maxSize.
@@ -24,6 +24,6 @@ func trim(queue *cache.FIFO, maxSize uint64) {
 }

 // popProcessNoopFunc is a no-op function that never returns an error.
-func popProcessNoopFunc(obj interface{}) error {
+func popProcessNoopFunc(_ interface{}) error {
 	return nil
 }
--- a/beacon-chain/cache/depositcache/BUILD.bazel
+++ b/beacon-chain/cache/depositcache/BUILD.bazel
@@ -5,6 +5,7 @@ go_library(
    name = "go_default_library",
    srcs = [
        "deposits_cache.go",
+        "log.go",
        "pending_deposits.go",
    ],
    importpath = "github.com/prysmaticlabs/prysm/beacon-chain/cache/depositcache",
@@ -13,6 +14,8 @@ go_library(
        "//proto/beacon/db:go_default_library",
        "//shared/bytesutil:go_default_library",
        "//shared/hashutil:go_default_library",
+        "//shared/params:go_default_library",
+        "//shared/trieutil:go_default_library",
        "@com_github_prometheus_client_golang//prometheus:go_default_library",
        "@com_github_prometheus_client_golang//prometheus/promauto:go_default_library",
        "@com_github_prysmaticlabs_ethereumapis//eth/v1alpha1:go_default_library",
@@ -24,13 +27,17 @@ go_library(
 go_test(
    name = "go_default_test",
    srcs = [
-        "deposits_test.go",
+        "deposits_cache_test.go",
        "pending_deposits_test.go",
    ],
    embed = [":go_default_library"],
    deps = [
        "//proto/beacon/db:go_default_library",
        "//shared/bytesutil:go_default_library",
+        "//shared/params:go_default_library",
+        "//shared/testutil/assert:go_default_library",
+        "//shared/testutil/require:go_default_library",
+        "//shared/trieutil:go_default_library",
        "@com_github_gogo_protobuf//proto:go_default_library",
        "@com_github_prysmaticlabs_ethereumapis//eth/v1alpha1:go_default_library",
        "@com_github_sirupsen_logrus//hooks/test:go_default_library",
--- a/beacon-chain/cache/depositcache/deposits_cache.go
+++ b/beacon-chain/cache/depositcache/deposits_cache.go
@@ -17,7 +17,9 @@ import (
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	dbpb "github.com/prysmaticlabs/prysm/proto/beacon/db"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
-	log "github.com/sirupsen/logrus"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/trieutil"
+	"github.com/sirupsen/logrus"
 	"go.opencensus.io/trace"
 )

@@ -30,30 +32,44 @@ var (

 // DepositFetcher defines a struct which can retrieve deposit information from a store.
 type DepositFetcher interface {
-	AllDeposits(ctx context.Context, beforeBlk *big.Int) []*ethpb.Deposit
+	AllDeposits(ctx context.Context, untilBlk *big.Int) []*ethpb.Deposit
 	DepositByPubkey(ctx context.Context, pubKey []byte) (*ethpb.Deposit, *big.Int)
 	DepositsNumberAndRootAtHeight(ctx context.Context, blockHeight *big.Int) (uint64, [32]byte)
+	FinalizedDeposits(ctx context.Context) *FinalizedDeposits
+	NonFinalizedDeposits(ctx context.Context, untilBlk *big.Int) []*ethpb.Deposit
+}
+
+// FinalizedDeposits stores the trie of deposits that have been included
+// in the beacon state up to the latest finalized checkpoint.
+type FinalizedDeposits struct {
+	Deposits        *trieutil.SparseMerkleTrie
+	MerkleTrieIndex int64
 }

 // DepositCache stores all in-memory deposit objects. This
 // stores all the deposit related data that is required by the beacon-node.
 type DepositCache struct {
 	// Beacon chain deposits in memory.
-	pendingDeposits    []*dbpb.DepositContainer
-	deposits           []*dbpb.DepositContainer
-	depositsLock       sync.RWMutex
-	chainStartDeposits []*ethpb.Deposit
-	chainStartPubkeys  map[string]bool
+	pendingDeposits   []*dbpb.DepositContainer
+	deposits          []*dbpb.DepositContainer
+	finalizedDeposits *FinalizedDeposits
+	depositsLock      sync.RWMutex
 }

-// NewDepositCache instantiates a new deposit cache
-func NewDepositCache() *DepositCache {
-	return &DepositCache{
-		pendingDeposits:    []*dbpb.DepositContainer{},
-		deposits:           []*dbpb.DepositContainer{},
-		chainStartPubkeys:  make(map[string]bool),
-		chainStartDeposits: make([]*ethpb.Deposit, 0),
+// New instantiates a new deposit cache
+func New() (*DepositCache, error) {
+	finalizedDepositsTrie, err := trieutil.NewTrie(params.BeaconConfig().DepositContractTreeDepth)
+	if err != nil {
+		return nil, err
 	}
+
+	// finalizedDeposits.MerkleTrieIndex is initialized to -1 because it represents the index of the last trie item.
+	// Inserting the first item into the trie will set the value of the index to 0.
+	return &DepositCache{
+		pendingDeposits:   []*dbpb.DepositContainer{},
+		deposits:          []*dbpb.DepositContainer{},
+		finalizedDeposits: &FinalizedDeposits{Deposits: finalizedDepositsTrie, MerkleTrieIndex: -1},
+	}, nil
 }

 // InsertDeposit into the database. If deposit or block number are nil
@@ -62,7 +78,7 @@ func (dc *DepositCache) InsertDeposit(ctx context.Context, d *ethpb.Deposit, blo
 	ctx, span := trace.StartSpan(ctx, "DepositsCache.InsertDeposit")
 	defer span.End()
 	if d == nil {
-		log.WithFields(log.Fields{
+		log.WithFields(logrus.Fields{
 			"block":        blockNum,
 			"deposit":      d,
 			"index":        index,
@@ -74,7 +90,9 @@ func (dc *DepositCache) InsertDeposit(ctx context.Context, d *ethpb.Deposit, blo
 	defer dc.depositsLock.Unlock()
 	// Keep the slice sorted on insertion in order to avoid costly sorting on retrieval.
 	heightIdx := sort.Search(len(dc.deposits), func(i int) bool { return dc.deposits[i].Index >= index })
-	newDeposits := append([]*dbpb.DepositContainer{{Deposit: d, Eth1BlockHeight: blockNum, DepositRoot: depositRoot[:], Index: index}}, dc.deposits[heightIdx:]...)
+	newDeposits := append(
+		[]*dbpb.DepositContainer{{Deposit: d, Eth1BlockHeight: blockNum, DepositRoot: depositRoot[:], Index: index}},
+		dc.deposits[heightIdx:]...)
 	dc.deposits = append(dc.deposits[:heightIdx], newDeposits...)
 	historicalDepositsCount.Inc()
 }
@@ -91,9 +109,40 @@ func (dc *DepositCache) InsertDepositContainers(ctx context.Context, ctrs []*dbp
 	historicalDepositsCount.Add(float64(len(ctrs)))
 }

-// AllDepositContainers returns a list of deposits all historical deposit containers until the given block number.
+// InsertFinalizedDeposits inserts deposits up to eth1DepositIndex (inclusive) into the finalized deposits cache.
+func (dc *DepositCache) InsertFinalizedDeposits(ctx context.Context, eth1DepositIndex int64) {
+	ctx, span := trace.StartSpan(ctx, "DepositsCache.InsertFinalizedDeposits")
+	defer span.End()
+	dc.depositsLock.Lock()
+	defer dc.depositsLock.Unlock()
+
+	depositTrie := dc.finalizedDeposits.Deposits
+	insertIndex := int(dc.finalizedDeposits.MerkleTrieIndex + 1)
+	for _, d := range dc.deposits {
+		if d.Index <= dc.finalizedDeposits.MerkleTrieIndex {
+			continue
+		}
+		if d.Index > eth1DepositIndex {
+			break
+		}
+		depHash, err := d.Deposit.Data.HashTreeRoot()
+		if err != nil {
+			log.WithError(err).Error("Could not hash deposit data. Finalized deposit cache not updated.")
+			return
+		}
+		depositTrie.Insert(depHash[:], insertIndex)
+		insertIndex++
+	}
+
+	dc.finalizedDeposits = &FinalizedDeposits{
+		Deposits:        depositTrie,
+		MerkleTrieIndex: eth1DepositIndex,
+	}
+}
+
+// AllDepositContainers returns all historical deposit containers.
 func (dc *DepositCache) AllDepositContainers(ctx context.Context) []*dbpb.DepositContainer {
-	ctx, span := trace.StartSpan(ctx, "BeaconDB.AllDepositContainers")
+	ctx, span := trace.StartSpan(ctx, "DepositsCache.AllDepositContainers")
 	defer span.End()
 	dc.depositsLock.RLock()
 	defer dc.depositsLock.RUnlock()
@@ -101,27 +150,9 @@ func (dc *DepositCache) AllDepositContainers(ctx context.Context) []*dbpb.Deposi
 	return dc.deposits
 }

-// MarkPubkeyForChainstart sets the pubkey deposit status to true.
-func (dc *DepositCache) MarkPubkeyForChainstart(ctx context.Context, pubkey string) {
-	ctx, span := trace.StartSpan(ctx, "DepositsCache.MarkPubkeyForChainstart")
-	defer span.End()
-	dc.chainStartPubkeys[pubkey] = true
-}
-
-// PubkeyInChainstart returns bool for whether the pubkey passed in has deposited.
-func (dc *DepositCache) PubkeyInChainstart(ctx context.Context, pubkey string) bool {
-	ctx, span := trace.StartSpan(ctx, "DepositsCache.PubkeyInChainstart")
-	defer span.End()
-	if dc.chainStartPubkeys != nil {
-		return dc.chainStartPubkeys[pubkey]
-	}
-	dc.chainStartPubkeys = make(map[string]bool)
-	return false
-}
-
-// AllDeposits returns a list of deposits all historical deposits until the given block number
+// AllDeposits returns a list of historical deposits until the given block number
 // (inclusive). If no block is specified then this method returns all historical deposits.
-func (dc *DepositCache) AllDeposits(ctx context.Context, beforeBlk *big.Int) []*ethpb.Deposit {
+func (dc *DepositCache) AllDeposits(ctx context.Context, untilBlk *big.Int) []*ethpb.Deposit {
 	ctx, span := trace.StartSpan(ctx, "DepositsCache.AllDeposits")
 	defer span.End()
 	dc.depositsLock.RLock()
@@ -129,7 +160,7 @@ func (dc *DepositCache) AllDeposits(ctx context.Context, beforeBlk *big.Int) []*

 	var deposits []*ethpb.Deposit
 	for _, ctnr := range dc.deposits {
-		if beforeBlk == nil || beforeBlk.Uint64() >= ctnr.Eth1BlockHeight {
+		if untilBlk == nil || untilBlk.Uint64() >= ctnr.Eth1BlockHeight {
 			deposits = append(deposits, ctnr.Deposit)
 		}
 	}
@@ -171,3 +202,64 @@ func (dc *DepositCache) DepositByPubkey(ctx context.Context, pubKey []byte) (*et
 	}
 	return deposit, blockNum
 }
+
+// FinalizedDeposits returns the finalized deposits trie.
+func (dc *DepositCache) FinalizedDeposits(ctx context.Context) *FinalizedDeposits {
+	ctx, span := trace.StartSpan(ctx, "DepositsCache.FinalizedDeposits")
+	defer span.End()
+	dc.depositsLock.RLock()
+	defer dc.depositsLock.RUnlock()
+
+	return &FinalizedDeposits{
+		Deposits:        dc.finalizedDeposits.Deposits.Copy(),
+		MerkleTrieIndex: dc.finalizedDeposits.MerkleTrieIndex,
+	}
+}
+
+// NonFinalizedDeposits returns the list of non-finalized deposits until the given block number (inclusive).
+// If no block is specified then this method returns all non-finalized deposits.
+func (dc *DepositCache) NonFinalizedDeposits(ctx context.Context, untilBlk *big.Int) []*ethpb.Deposit {
+	ctx, span := trace.StartSpan(ctx, "DepositsCache.NonFinalizedDeposits")
+	defer span.End()
+	dc.depositsLock.RLock()
+	defer dc.depositsLock.RUnlock()
+
+	if dc.finalizedDeposits == nil {
+		return dc.AllDeposits(ctx, untilBlk)
+	}
+
+	lastFinalizedDepositIndex := dc.finalizedDeposits.MerkleTrieIndex
+	var deposits []*ethpb.Deposit
+	for _, d := range dc.deposits {
+		if (d.Index > lastFinalizedDepositIndex) && (untilBlk == nil || untilBlk.Uint64() >= d.Eth1BlockHeight) {
+			deposits = append(deposits, d.Deposit)
+		}
+	}
+
+	return deposits
+}
+
+// PruneProofs removes proofs from all deposits whose index is equal or less than untilDepositIndex.
+func (dc *DepositCache) PruneProofs(ctx context.Context, untilDepositIndex int64) error {
+	ctx, span := trace.StartSpan(ctx, "DepositsCache.PruneProofs")
+	defer span.End()
+	dc.depositsLock.Lock()
+	defer dc.depositsLock.Unlock()
+
+	if untilDepositIndex >= int64(len(dc.deposits)) {
+		untilDepositIndex = int64(len(dc.deposits) - 1)
+	}
+
+	for i := untilDepositIndex; i >= 0; i-- {
+		if ctx.Err() != nil {
+			return ctx.Err()
+		}
+		// Finding a nil proof means that all proofs up to this deposit have been already pruned.
+		if dc.deposits[i].Deposit.Proof == nil {
+			break
+		}
+		dc.deposits[i].Deposit.Proof = nil
+	}
+
+	return nil
+}
--- a/beacon-chain/cache/depositcache/deposits_cache_test.go
+++ b/beacon-chain/cache/depositcache/deposits_cache_test.go
@@ -0,0 +1,752 @@
+package depositcache
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"math/big"
+	"testing"
+
+	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
+	dbpb "github.com/prysmaticlabs/prysm/proto/beacon/db"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+	"github.com/prysmaticlabs/prysm/shared/trieutil"
+	logTest "github.com/sirupsen/logrus/hooks/test"
+)
+
+const nilDepositErr = "Ignoring nil deposit insertion"
+
+var _ DepositFetcher = (*DepositCache)(nil)
+
+func TestInsertDeposit_LogsOnNilDepositInsertion(t *testing.T) {
+	hook := logTest.NewGlobal()
+	dc, err := New()
+	require.NoError(t, err)
+
+	dc.InsertDeposit(context.Background(), nil, 1, 0, [32]byte{})
+
+	require.Equal(t, 0, len(dc.deposits), "Number of deposits changed")
+	assert.Equal(t, nilDepositErr, hook.LastEntry().Message)
+}
+
+func TestInsertDeposit_MaintainsSortedOrderByIndex(t *testing.T) {
+	dc, err := New()
+	require.NoError(t, err)
+
+	insertions := []struct {
+		blkNum  uint64
+		deposit *ethpb.Deposit
+		index   int64
+	}{
+		{
+			blkNum:  0,
+			deposit: &ethpb.Deposit{},
+			index:   0,
+		},
+		{
+			blkNum:  0,
+			deposit: &ethpb.Deposit{},
+			index:   3,
+		},
+		{
+			blkNum:  0,
+			deposit: &ethpb.Deposit{},
+			index:   1,
+		},
+		{
+			blkNum:  0,
+			deposit: &ethpb.Deposit{},
+			index:   4,
+		},
+	}
+
+	for _, ins := range insertions {
+		dc.InsertDeposit(context.Background(), ins.deposit, ins.blkNum, ins.index, [32]byte{})
+	}
+
+	expectedIndices := []int64{0, 1, 3, 4}
+	for i, ei := range expectedIndices {
+		assert.Equal(t, ei, dc.deposits[i].Index,
+			fmt.Sprintf("dc.deposits[%d].Index = %d, wanted %d", i, dc.deposits[i].Index, ei))
+	}
+}
+
+func TestAllDeposits_ReturnsAllDeposits(t *testing.T) {
+	dc, err := New()
+	require.NoError(t, err)
+
+	deposits := []*dbpb.DepositContainer{
+		{
+			Eth1BlockHeight: 10,
+			Deposit:         &ethpb.Deposit{},
+		},
+		{
+			Eth1BlockHeight: 10,
+			Deposit:         &ethpb.Deposit{},
+		},
+		{
+			Eth1BlockHeight: 10,
+			Deposit:         &ethpb.Deposit{},
+		},
+		{
+			Eth1BlockHeight: 11,
+			Deposit:         &ethpb.Deposit{},
+		},
+		{
+			Eth1BlockHeight: 11,
+			Deposit:         &ethpb.Deposit{},
+		},
+		{
+			Eth1BlockHeight: 12,
+			Deposit:         &ethpb.Deposit{},
+		},
+		{
+			Eth1BlockHeight: 12,
+			Deposit:         &ethpb.Deposit{},
+		},
+	}
+	dc.deposits = deposits
+
+	d := dc.AllDeposits(context.Background(), nil)
+	assert.Equal(t, len(deposits), len(d))
+}
+
+func TestAllDeposits_FiltersDepositUpToAndIncludingBlockNumber(t *testing.T) {
+	dc, err := New()
+	require.NoError(t, err)
+
+	deposits := []*dbpb.DepositContainer{
+		{
+			Eth1BlockHeight: 10,
+			Deposit:         &ethpb.Deposit{},
+		},
+		{
+			Eth1BlockHeight: 10,
+			Deposit:         &ethpb.Deposit{},
+		},
+		{
+			Eth1BlockHeight: 10,
+			Deposit:         &ethpb.Deposit{},
+		},
+		{
+			Eth1BlockHeight: 11,
+			Deposit:         &ethpb.Deposit{},
+		},
+		{
+			Eth1BlockHeight: 11,
+			Deposit:         &ethpb.Deposit{},
+		},
+		{
+			Eth1BlockHeight: 12,
+			Deposit:         &ethpb.Deposit{},
+		},
+		{
+			Eth1BlockHeight: 12,
+			Deposit:         &ethpb.Deposit{},
+		},
+	}
+	dc.deposits = deposits
+
+	d := dc.AllDeposits(context.Background(), big.NewInt(11))
+	assert.Equal(t, 5, len(d))
+}
+
+func TestDepositsNumberAndRootAtHeight_ReturnsAppropriateCountAndRoot(t *testing.T) {
+	dc, err := New()
+	require.NoError(t, err)
+
+	dc.deposits = []*dbpb.DepositContainer{
+		{
+			Eth1BlockHeight: 10,
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             make([]byte, 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+		},
+		{
+			Eth1BlockHeight: 10,
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             make([]byte, 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+		},
+		{
+			Eth1BlockHeight: 10,
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             make([]byte, 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+		},
+		{
+			Eth1BlockHeight: 10,
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             make([]byte, 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+		},
+		{
+			Eth1BlockHeight: 11,
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             make([]byte, 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+			DepositRoot: bytesutil.PadTo([]byte("root"), 32),
+		},
+		{
+			Eth1BlockHeight: 12,
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             make([]byte, 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+		},
+		{
+			Eth1BlockHeight: 12,
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             make([]byte, 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+		},
+	}
+
+	n, root := dc.DepositsNumberAndRootAtHeight(context.Background(), big.NewInt(11))
+	assert.Equal(t, 5, int(n))
+	assert.Equal(t, bytesutil.ToBytes32([]byte("root")), root)
+}
+
+func TestDepositsNumberAndRootAtHeight_ReturnsEmptyTrieIfBlockHeightLessThanOldestDeposit(t *testing.T) {
+	dc, err := New()
+	require.NoError(t, err)
+
+	dc.deposits = []*dbpb.DepositContainer{
+		{
+			Eth1BlockHeight: 10,
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             make([]byte, 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+			DepositRoot: bytesutil.PadTo([]byte("root"), 32),
+		},
+		{
+			Eth1BlockHeight: 11,
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             make([]byte, 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+			DepositRoot: bytesutil.PadTo([]byte("root"), 32),
+		},
+	}
+
+	n, root := dc.DepositsNumberAndRootAtHeight(context.Background(), big.NewInt(2))
+	assert.Equal(t, 0, int(n))
+	assert.Equal(t, [32]byte{}, root)
+}
+
+func TestDepositByPubkey_ReturnsFirstMatchingDeposit(t *testing.T) {
+	dc, err := New()
+	require.NoError(t, err)
+
+	dc.deposits = []*dbpb.DepositContainer{
+		{
+			Eth1BlockHeight: 9,
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             bytesutil.PadTo([]byte("pk0"), 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+		},
+		{
+			Eth1BlockHeight: 10,
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             bytesutil.PadTo([]byte("pk1"), 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+		},
+		{
+			Eth1BlockHeight: 11,
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             bytesutil.PadTo([]byte("pk1"), 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+		},
+		{
+			Eth1BlockHeight: 12,
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             bytesutil.PadTo([]byte("pk2"), 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+		},
+	}
+
+	pk1 := bytesutil.PadTo([]byte("pk1"), 48)
+	dep, blkNum := dc.DepositByPubkey(context.Background(), pk1)
+
+	if dep == nil || !bytes.Equal(dep.Data.PublicKey, pk1) {
+		t.Error("Returned wrong deposit")
+	}
+	assert.Equal(t, 0, blkNum.Cmp(big.NewInt(10)),
+		fmt.Sprintf("Returned wrong block number %v", blkNum))
+}
+
+func TestFinalizedDeposits_DepositsCachedCorrectly(t *testing.T) {
+	dc, err := New()
+	require.NoError(t, err)
+
+	finalizedDeposits := []*dbpb.DepositContainer{
+		{
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             bytesutil.PadTo([]byte{0}, 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+			Index: 0,
+		},
+		{
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             bytesutil.PadTo([]byte{1}, 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+			Index: 1,
+		},
+		{
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             bytesutil.PadTo([]byte{2}, 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+			Index: 2,
+		},
+	}
+	dc.deposits = append(finalizedDeposits, &dbpb.DepositContainer{
+		Deposit: &ethpb.Deposit{
+			Data: &ethpb.Deposit_Data{
+				PublicKey:             bytesutil.PadTo([]byte{3}, 48),
+				WithdrawalCredentials: make([]byte, 32),
+				Signature:             make([]byte, 96),
+			},
+		},
+		Index: 3,
+	})
+
+	dc.InsertFinalizedDeposits(context.Background(), 2)
+
+	cachedDeposits := dc.FinalizedDeposits(context.Background())
+	require.NotNil(t, cachedDeposits, "Deposits not cached")
+	assert.Equal(t, int64(2), cachedDeposits.MerkleTrieIndex)
+
+	var deps [][]byte
+	for _, d := range finalizedDeposits {
+		hash, err := d.Deposit.Data.HashTreeRoot()
+		require.NoError(t, err, "Could not hash deposit data")
+		deps = append(deps, hash[:])
+	}
+	trie, err := trieutil.GenerateTrieFromItems(deps, params.BeaconConfig().DepositContractTreeDepth)
+	require.NoError(t, err, "Could not generate deposit trie")
+	assert.Equal(t, trie.HashTreeRoot(), cachedDeposits.Deposits.HashTreeRoot())
+}
+
+func TestFinalizedDeposits_UtilizesPreviouslyCachedDeposits(t *testing.T) {
+	dc, err := New()
+	require.NoError(t, err)
+
+	oldFinalizedDeposits := []*dbpb.DepositContainer{
+		{
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             bytesutil.PadTo([]byte{0}, 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+			Index: 0,
+		},
+		{
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             bytesutil.PadTo([]byte{1}, 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+			Index: 1,
+		},
+	}
+	newFinalizedDeposit := dbpb.DepositContainer{
+		Deposit: &ethpb.Deposit{
+			Data: &ethpb.Deposit_Data{
+				PublicKey:             bytesutil.PadTo([]byte{2}, 48),
+				WithdrawalCredentials: make([]byte, 32),
+				Signature:             make([]byte, 96),
+			},
+		},
+		Index: 2,
+	}
+	dc.deposits = oldFinalizedDeposits
+	dc.InsertFinalizedDeposits(context.Background(), 1)
+	// Artificially exclude old deposits so that they can only be retrieved from previously finalized deposits.
+	dc.deposits = []*dbpb.DepositContainer{&newFinalizedDeposit}
+
+	dc.InsertFinalizedDeposits(context.Background(), 2)
+
+	cachedDeposits := dc.FinalizedDeposits(context.Background())
+	require.NotNil(t, cachedDeposits, "Deposits not cached")
+	assert.Equal(t, int64(2), cachedDeposits.MerkleTrieIndex)
+
+	var deps [][]byte
+	for _, d := range append(oldFinalizedDeposits, &newFinalizedDeposit) {
+		hash, err := d.Deposit.Data.HashTreeRoot()
+		require.NoError(t, err, "Could not hash deposit data")
+		deps = append(deps, hash[:])
+	}
+	trie, err := trieutil.GenerateTrieFromItems(deps, params.BeaconConfig().DepositContractTreeDepth)
+	require.NoError(t, err, "Could not generate deposit trie")
+	assert.Equal(t, trie.HashTreeRoot(), cachedDeposits.Deposits.HashTreeRoot())
+}
+
+func TestFinalizedDeposits_InitializedCorrectly(t *testing.T) {
+	dc, err := New()
+	require.NoError(t, err)
+
+	finalizedDeposits := dc.finalizedDeposits
+	assert.NotNil(t, finalizedDeposits)
+	assert.NotNil(t, finalizedDeposits.Deposits)
+	assert.Equal(t, int64(-1), finalizedDeposits.MerkleTrieIndex)
+}
+
+func TestNonFinalizedDeposits_ReturnsAllNonFinalizedDeposits(t *testing.T) {
+	dc, err := New()
+	require.NoError(t, err)
+
+	finalizedDeposits := []*dbpb.DepositContainer{
+		{
+			Eth1BlockHeight: 10,
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             bytesutil.PadTo([]byte{0}, 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+			Index: 0,
+		},
+		{
+			Eth1BlockHeight: 10,
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             bytesutil.PadTo([]byte{1}, 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+			Index: 1,
+		},
+	}
+	dc.deposits = append(finalizedDeposits,
+		&dbpb.DepositContainer{
+			Eth1BlockHeight: 10,
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             bytesutil.PadTo([]byte{2}, 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+			Index: 2,
+		},
+		&dbpb.DepositContainer{
+			Eth1BlockHeight: 11,
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             bytesutil.PadTo([]byte{3}, 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+			Index: 3,
+		})
+	dc.InsertFinalizedDeposits(context.Background(), 1)
+
+	deps := dc.NonFinalizedDeposits(context.Background(), nil)
+	assert.Equal(t, 2, len(deps))
+}
+
+func TestNonFinalizedDeposits_ReturnsNonFinalizedDepositsUpToBlockNumber(t *testing.T) {
+	dc, err := New()
+	require.NoError(t, err)
+
+	finalizedDeposits := []*dbpb.DepositContainer{
+		{
+			Eth1BlockHeight: 10,
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             bytesutil.PadTo([]byte{0}, 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+			Index: 0,
+		},
+		{
+			Eth1BlockHeight: 10,
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             bytesutil.PadTo([]byte{1}, 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+			Index: 1,
+		},
+	}
+	dc.deposits = append(finalizedDeposits,
+		&dbpb.DepositContainer{
+			Eth1BlockHeight: 10,
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             bytesutil.PadTo([]byte{2}, 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+			Index: 2,
+		},
+		&dbpb.DepositContainer{
+			Eth1BlockHeight: 11,
+			Deposit: &ethpb.Deposit{
+				Data: &ethpb.Deposit_Data{
+					PublicKey:             bytesutil.PadTo([]byte{3}, 48),
+					WithdrawalCredentials: make([]byte, 32),
+					Signature:             make([]byte, 96),
+				},
+			},
+			Index: 3,
+		})
+	dc.InsertFinalizedDeposits(context.Background(), 1)
+
+	deps := dc.NonFinalizedDeposits(context.Background(), big.NewInt(10))
+	assert.Equal(t, 1, len(deps))
+}
+
+func TestPruneProofs_Ok(t *testing.T) {
+	dc, err := New()
+	require.NoError(t, err)
+
+	deposits := []struct {
+		blkNum  uint64
+		deposit *ethpb.Deposit
+		index   int64
+	}{
+		{
+			blkNum:  0,
+			deposit: &ethpb.Deposit{Proof: makeDepositProof()},
+			index:   0,
+		},
+		{
+			blkNum:  0,
+			deposit: &ethpb.Deposit{Proof: makeDepositProof()},
+			index:   1,
+		},
+		{
+			blkNum:  0,
+			deposit: &ethpb.Deposit{Proof: makeDepositProof()},
+			index:   2,
+		},
+		{
+			blkNum:  0,
+			deposit: &ethpb.Deposit{Proof: makeDepositProof()},
+			index:   3,
+		},
+	}
+
+	for _, ins := range deposits {
+		dc.InsertDeposit(context.Background(), ins.deposit, ins.blkNum, ins.index, [32]byte{})
+	}
+
+	require.NoError(t, dc.PruneProofs(context.Background(), 1))
+
+	assert.DeepEqual(t, [][]byte(nil), dc.deposits[0].Deposit.Proof)
+	assert.DeepEqual(t, [][]byte(nil), dc.deposits[1].Deposit.Proof)
+	assert.NotNil(t, dc.deposits[2].Deposit.Proof)
+	assert.NotNil(t, dc.deposits[3].Deposit.Proof)
+}
+
+func TestPruneProofs_SomeAlreadyPruned(t *testing.T) {
+	dc, err := New()
+	require.NoError(t, err)
+
+	deposits := []struct {
+		blkNum  uint64
+		deposit *ethpb.Deposit
+		index   int64
+	}{
+		{
+			blkNum:  0,
+			deposit: &ethpb.Deposit{Proof: nil},
+			index:   0,
+		},
+		{
+			blkNum:  0,
+			deposit: &ethpb.Deposit{Proof: nil},
+			index:   1,
+		},
+		{
+			blkNum:  0,
+			deposit: &ethpb.Deposit{Proof: makeDepositProof()},
+			index:   2,
+		},
+		{
+			blkNum:  0,
+			deposit: &ethpb.Deposit{Proof: makeDepositProof()},
+			index:   3,
+		},
+	}
+
+	for _, ins := range deposits {
+		dc.InsertDeposit(context.Background(), ins.deposit, ins.blkNum, ins.index, [32]byte{})
+	}
+
+	require.NoError(t, dc.PruneProofs(context.Background(), 2))
+
+	assert.DeepEqual(t, [][]byte(nil), dc.deposits[2].Deposit.Proof)
+}
+
+func TestPruneProofs_PruneAllWhenDepositIndexTooBig(t *testing.T) {
+	dc, err := New()
+	require.NoError(t, err)
+
+	deposits := []struct {
+		blkNum  uint64
+		deposit *ethpb.Deposit
+		index   int64
+	}{
+		{
+			blkNum:  0,
+			deposit: &ethpb.Deposit{Proof: makeDepositProof()},
+			index:   0,
+		},
+		{
+			blkNum:  0,
+			deposit: &ethpb.Deposit{Proof: makeDepositProof()},
+			index:   1,
+		},
+		{
+			blkNum:  0,
+			deposit: &ethpb.Deposit{Proof: makeDepositProof()},
+			index:   2,
+		},
+		{
+			blkNum:  0,
+			deposit: &ethpb.Deposit{Proof: makeDepositProof()},
+			index:   3,
+		},
+	}
+
+	for _, ins := range deposits {
+		dc.InsertDeposit(context.Background(), ins.deposit, ins.blkNum, ins.index, [32]byte{})
+	}
+
+	require.NoError(t, dc.PruneProofs(context.Background(), 99))
+
+	assert.DeepEqual(t, [][]byte(nil), dc.deposits[0].Deposit.Proof)
+	assert.DeepEqual(t, [][]byte(nil), dc.deposits[1].Deposit.Proof)
+	assert.DeepEqual(t, [][]byte(nil), dc.deposits[2].Deposit.Proof)
+	assert.DeepEqual(t, [][]byte(nil), dc.deposits[3].Deposit.Proof)
+}
+
+func TestPruneProofs_CorrectlyHandleLastIndex(t *testing.T) {
+	dc, err := New()
+	require.NoError(t, err)
+
+	deposits := []struct {
+		blkNum  uint64
+		deposit *ethpb.Deposit
+		index   int64
+	}{
+		{
+			blkNum:  0,
+			deposit: &ethpb.Deposit{Proof: makeDepositProof()},
+			index:   0,
+		},
+		{
+			blkNum:  0,
+			deposit: &ethpb.Deposit{Proof: makeDepositProof()},
+			index:   1,
+		},
+		{
+			blkNum:  0,
+			deposit: &ethpb.Deposit{Proof: makeDepositProof()},
+			index:   2,
+		},
+		{
+			blkNum:  0,
+			deposit: &ethpb.Deposit{Proof: makeDepositProof()},
+			index:   3,
+		},
+	}
+
+	for _, ins := range deposits {
+		dc.InsertDeposit(context.Background(), ins.deposit, ins.blkNum, ins.index, [32]byte{})
+	}
+
+	require.NoError(t, dc.PruneProofs(context.Background(), 4))
+
+	assert.DeepEqual(t, [][]byte(nil), dc.deposits[0].Deposit.Proof)
+	assert.DeepEqual(t, [][]byte(nil), dc.deposits[1].Deposit.Proof)
+	assert.DeepEqual(t, [][]byte(nil), dc.deposits[2].Deposit.Proof)
+	assert.DeepEqual(t, [][]byte(nil), dc.deposits[3].Deposit.Proof)
+}
+
+func makeDepositProof() [][]byte {
+	proof := make([][]byte, int(params.BeaconConfig().DepositContractTreeDepth)+1)
+	for i := range proof {
+		proof[i] = make([]byte, 32)
+	}
+	return proof
+}
--- a/beacon-chain/cache/depositcache/deposits_test.go
+++ b/beacon-chain/cache/depositcache/deposits_test.go
@@ -1,275 +0,0 @@
-package depositcache
-
-import (
-	"bytes"
-	"context"
-	"math/big"
-	"testing"
-
-	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
-	dbpb "github.com/prysmaticlabs/prysm/proto/beacon/db"
-	"github.com/prysmaticlabs/prysm/shared/bytesutil"
-	logTest "github.com/sirupsen/logrus/hooks/test"
-)
-
-const nilDepositErr = "Ignoring nil deposit insertion"
-
-var _ = DepositFetcher(&DepositCache{})
-
-func TestBeaconDB_InsertDeposit_LogsOnNilDepositInsertion(t *testing.T) {
-	hook := logTest.NewGlobal()
-	dc := DepositCache{}
-
-	dc.InsertDeposit(context.Background(), nil, 1, 0, [32]byte{})
-
-	if len(dc.deposits) != 0 {
-		t.Fatal("Number of deposits changed")
-	}
-	if hook.LastEntry().Message != nilDepositErr {
-		t.Errorf("Did not log correct message, wanted \"Ignoring nil deposit insertion\", got \"%s\"", hook.LastEntry().Message)
-	}
-}
-
-func TestBeaconDB_InsertDeposit_MaintainsSortedOrderByIndex(t *testing.T) {
-	dc := DepositCache{}
-
-	insertions := []struct {
-		blkNum  uint64
-		deposit *ethpb.Deposit
-		index   int64
-	}{
-		{
-			blkNum:  0,
-			deposit: &ethpb.Deposit{},
-			index:   0,
-		},
-		{
-			blkNum:  0,
-			deposit: &ethpb.Deposit{},
-			index:   3,
-		},
-		{
-			blkNum:  0,
-			deposit: &ethpb.Deposit{},
-			index:   1,
-		},
-		{
-			blkNum:  0,
-			deposit: &ethpb.Deposit{},
-			index:   4,
-		},
-	}
-
-	for _, ins := range insertions {
-		dc.InsertDeposit(context.Background(), ins.deposit, ins.blkNum, ins.index, [32]byte{})
-	}
-
-	expectedIndices := []int64{0, 1, 3, 4}
-	for i, ei := range expectedIndices {
-		if dc.deposits[i].Index != ei {
-			t.Errorf("dc.deposits[%d].Index = %d, wanted %d", i, dc.deposits[i].Index, ei)
-		}
-	}
-}
-
-func TestBeaconDB_AllDeposits_ReturnsAllDeposits(t *testing.T) {
-	dc := DepositCache{}
-
-	deposits := []*dbpb.DepositContainer{
-		{
-			Eth1BlockHeight: 10,
-			Deposit:         &ethpb.Deposit{},
-		},
-		{
-			Eth1BlockHeight: 10,
-			Deposit:         &ethpb.Deposit{},
-		},
-		{
-			Eth1BlockHeight: 10,
-			Deposit:         &ethpb.Deposit{},
-		},
-		{
-			Eth1BlockHeight: 11,
-			Deposit:         &ethpb.Deposit{},
-		},
-		{
-			Eth1BlockHeight: 11,
-			Deposit:         &ethpb.Deposit{},
-		},
-		{
-			Eth1BlockHeight: 12,
-			Deposit:         &ethpb.Deposit{},
-		},
-		{
-			Eth1BlockHeight: 12,
-			Deposit:         &ethpb.Deposit{},
-		},
-	}
-	dc.deposits = deposits
-
-	d := dc.AllDeposits(context.Background(), nil)
-	if len(d) != len(deposits) {
-		t.Errorf("Return the wrong number of deposits (%d) wanted %d", len(d), len(deposits))
-	}
-}
-
-func TestBeaconDB_AllDeposits_FiltersDepositUpToAndIncludingBlockNumber(t *testing.T) {
-	dc := DepositCache{}
-
-	deposits := []*dbpb.DepositContainer{
-		{
-			Eth1BlockHeight: 10,
-			Deposit:         &ethpb.Deposit{},
-		},
-		{
-			Eth1BlockHeight: 10,
-			Deposit:         &ethpb.Deposit{},
-		},
-		{
-			Eth1BlockHeight: 10,
-			Deposit:         &ethpb.Deposit{},
-		},
-		{
-			Eth1BlockHeight: 11,
-			Deposit:         &ethpb.Deposit{},
-		},
-		{
-			Eth1BlockHeight: 11,
-			Deposit:         &ethpb.Deposit{},
-		},
-		{
-			Eth1BlockHeight: 12,
-			Deposit:         &ethpb.Deposit{},
-		},
-		{
-			Eth1BlockHeight: 12,
-			Deposit:         &ethpb.Deposit{},
-		},
-	}
-	dc.deposits = deposits
-
-	d := dc.AllDeposits(context.Background(), big.NewInt(11))
-	expected := 5
-	if len(d) != expected {
-		t.Errorf("Return the wrong number of deposits (%d) wanted %d", len(d), expected)
-	}
-}
-
-func TestBeaconDB_DepositsNumberAndRootAtHeight_ReturnsAppropriateCountAndRoot(t *testing.T) {
-	dc := DepositCache{}
-
-	dc.deposits = []*dbpb.DepositContainer{
-		{
-			Eth1BlockHeight: 10,
-			Deposit:         &ethpb.Deposit{},
-		},
-		{
-			Eth1BlockHeight: 10,
-			Deposit:         &ethpb.Deposit{},
-		},
-		{
-			Eth1BlockHeight: 10,
-			Deposit:         &ethpb.Deposit{},
-		},
-		{
-			Eth1BlockHeight: 10,
-			Deposit:         &ethpb.Deposit{},
-		},
-		{
-			Eth1BlockHeight: 11,
-			Deposit:         &ethpb.Deposit{},
-			DepositRoot:     []byte("root"),
-		},
-		{
-			Eth1BlockHeight: 12,
-			Deposit:         &ethpb.Deposit{},
-		},
-		{
-			Eth1BlockHeight: 12,
-			Deposit:         &ethpb.Deposit{},
-		},
-	}
-
-	n, root := dc.DepositsNumberAndRootAtHeight(context.Background(), big.NewInt(11))
-	if n != 5 {
-		t.Errorf("Returned unexpected deposits number %d wanted %d", n, 5)
-	}
-
-	if root != bytesutil.ToBytes32([]byte("root")) {
-		t.Errorf("Returned unexpected root: %v", root)
-	}
-}
-
-func TestBeaconDB_DepositsNumberAndRootAtHeight_ReturnsEmptyTrieIfBlockHeightLessThanOldestDeposit(t *testing.T) {
-	dc := DepositCache{}
-
-	dc.deposits = []*dbpb.DepositContainer{
-		{
-			Eth1BlockHeight: 10,
-			Deposit:         &ethpb.Deposit{},
-			DepositRoot:     []byte("root"),
-		},
-		{
-			Eth1BlockHeight: 11,
-			Deposit:         &ethpb.Deposit{},
-			DepositRoot:     []byte("root"),
-		},
-	}
-
-	n, root := dc.DepositsNumberAndRootAtHeight(context.Background(), big.NewInt(2))
-	if n != 0 {
-		t.Errorf("Returned unexpected deposits number %d wanted %d", n, 0)
-	}
-
-	if root != [32]byte{} {
-		t.Errorf("Returned unexpected root: %v", root)
-	}
-}
-
-func TestBeaconDB_DepositByPubkey_ReturnsFirstMatchingDeposit(t *testing.T) {
-	dc := DepositCache{}
-
-	dc.deposits = []*dbpb.DepositContainer{
-		{
-			Eth1BlockHeight: 9,
-			Deposit: &ethpb.Deposit{
-				Data: &ethpb.Deposit_Data{
-					PublicKey: []byte("pk0"),
-				},
-			},
-		},
-		{
-			Eth1BlockHeight: 10,
-			Deposit: &ethpb.Deposit{
-				Data: &ethpb.Deposit_Data{
-					PublicKey: []byte("pk1"),
-				},
-			},
-		},
-		{
-			Eth1BlockHeight: 11,
-			Deposit: &ethpb.Deposit{
-				Data: &ethpb.Deposit_Data{
-					PublicKey: []byte("pk1"),
-				},
-			},
-		},
-		{
-			Eth1BlockHeight: 12,
-			Deposit: &ethpb.Deposit{
-				Data: &ethpb.Deposit_Data{
-					PublicKey: []byte("pk2"),
-				},
-			},
-		},
-	}
-
-	dep, blkNum := dc.DepositByPubkey(context.Background(), []byte("pk1"))
-
-	if !bytes.Equal(dep.Data.PublicKey, []byte("pk1")) {
-		t.Error("Returned wrong deposit")
-	}
-	if blkNum.Cmp(big.NewInt(10)) != 0 {
-		t.Errorf("Returned wrong block number %v", blkNum)
-	}
-}
--- a/beacon-chain/cache/depositcache/log.go
+++ b/beacon-chain/cache/depositcache/log.go
@@ -0,0 +1,5 @@
+package depositcache
+
+import "github.com/sirupsen/logrus"
+
+var log = logrus.WithField("prefix", "depositcache")
--- a/beacon-chain/cache/depositcache/pending_deposits.go
+++ b/beacon-chain/cache/depositcache/pending_deposits.go
@@ -10,7 +10,7 @@ import (
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	dbpb "github.com/prysmaticlabs/prysm/proto/beacon/db"
 	"github.com/prysmaticlabs/prysm/shared/hashutil"
-	log "github.com/sirupsen/logrus"
+	"github.com/sirupsen/logrus"
 	"go.opencensus.io/trace"
 )

@@ -24,7 +24,7 @@ var (
 // PendingDepositsFetcher specifically outlines a struct that can retrieve deposits
 // which have not yet been included in the chain.
 type PendingDepositsFetcher interface {
-	PendingContainers(ctx context.Context, beforeBlk *big.Int) []*dbpb.DepositContainer
+	PendingContainers(ctx context.Context, untilBlk *big.Int) []*dbpb.DepositContainer
 }

 // InsertPendingDeposit into the database. If deposit or block number are nil
@@ -33,7 +33,7 @@ func (dc *DepositCache) InsertPendingDeposit(ctx context.Context, d *ethpb.Depos
 	ctx, span := trace.StartSpan(ctx, "DepositsCache.InsertPendingDeposit")
 	defer span.End()
 	if d == nil {
-		log.WithFields(log.Fields{
+		log.WithFields(logrus.Fields{
 			"block":   blockNum,
 			"deposit": d,
 		}).Debug("Ignoring nil deposit insertion")
@@ -50,36 +50,23 @@ func (dc *DepositCache) InsertPendingDeposit(ctx context.Context, d *ethpb.Depos
 // PendingDeposits returns a list of deposits until the given block number
 // (inclusive). If no block is specified then this method returns all pending
 // deposits.
-func (dc *DepositCache) PendingDeposits(ctx context.Context, beforeBlk *big.Int) []*ethpb.Deposit {
+func (dc *DepositCache) PendingDeposits(ctx context.Context, untilBlk *big.Int) []*ethpb.Deposit {
 	ctx, span := trace.StartSpan(ctx, "DepositsCache.PendingDeposits")
 	defer span.End()
-	dc.depositsLock.RLock()
-	defer dc.depositsLock.RUnlock()

-	var depositCntrs []*dbpb.DepositContainer
-	for _, ctnr := range dc.pendingDeposits {
-		if beforeBlk == nil || beforeBlk.Uint64() >= ctnr.Eth1BlockHeight {
-			depositCntrs = append(depositCntrs, ctnr)
-		}
-	}
-	// Sort the deposits by Merkle index.
-	sort.SliceStable(depositCntrs, func(i, j int) bool {
-		return depositCntrs[i].Index < depositCntrs[j].Index
-	})
+	depositCntrs := dc.PendingContainers(ctx, untilBlk)

 	var deposits []*ethpb.Deposit
 	for _, dep := range depositCntrs {
 		deposits = append(deposits, dep.Deposit)
 	}

-	span.AddAttributes(trace.Int64Attribute("count", int64(len(deposits))))
-
 	return deposits
 }

 // PendingContainers returns a list of deposit containers until the given block number
 // (inclusive).
-func (dc *DepositCache) PendingContainers(ctx context.Context, beforeBlk *big.Int) []*dbpb.DepositContainer {
+func (dc *DepositCache) PendingContainers(ctx context.Context, untilBlk *big.Int) []*dbpb.DepositContainer {
 	ctx, span := trace.StartSpan(ctx, "DepositsCache.PendingDeposits")
 	defer span.End()
 	dc.depositsLock.RLock()
@@ -87,7 +74,7 @@ func (dc *DepositCache) PendingContainers(ctx context.Context, beforeBlk *big.In

 	var depositCntrs []*dbpb.DepositContainer
 	for _, ctnr := range dc.pendingDeposits {
-		if beforeBlk == nil || beforeBlk.Uint64() >= ctnr.Eth1BlockHeight {
+		if untilBlk == nil || untilBlk.Uint64() >= ctnr.Eth1BlockHeight {
 			depositCntrs = append(depositCntrs, ctnr)
 		}
 	}
@@ -141,7 +128,7 @@ func (dc *DepositCache) RemovePendingDeposit(ctx context.Context, d *ethpb.Depos
 }

 // PrunePendingDeposits removes any deposit which is older than the given deposit merkle tree index.
-func (dc *DepositCache) PrunePendingDeposits(ctx context.Context, merkleTreeIndex int) {
+func (dc *DepositCache) PrunePendingDeposits(ctx context.Context, merkleTreeIndex int64) {
 	ctx, span := trace.StartSpan(ctx, "DepositsCache.PrunePendingDeposits")
 	defer span.End()

@@ -155,7 +142,7 @@ func (dc *DepositCache) PrunePendingDeposits(ctx context.Context, merkleTreeInde

 	var cleanDeposits []*dbpb.DepositContainer
 	for _, dp := range dc.pendingDeposits {
-		if dp.Index >= int64(merkleTreeIndex) {
+		if dp.Index >= merkleTreeIndex {
 			cleanDeposits = append(cleanDeposits, dp)
 		}
 	}
--- a/beacon-chain/cache/depositcache/pending_deposits_test.go
+++ b/beacon-chain/cache/depositcache/pending_deposits_test.go
@@ -3,43 +3,45 @@ package depositcache
 import (
 	"context"
 	"math/big"
-	"reflect"
 	"testing"

 	"github.com/gogo/protobuf/proto"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	dbpb "github.com/prysmaticlabs/prysm/proto/beacon/db"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
 )

-var _ = PendingDepositsFetcher(&DepositCache{})
+var _ PendingDepositsFetcher = (*DepositCache)(nil)

 func TestInsertPendingDeposit_OK(t *testing.T) {
 	dc := DepositCache{}
 	dc.InsertPendingDeposit(context.Background(), &ethpb.Deposit{}, 111, 100, [32]byte{})

-	if len(dc.pendingDeposits) != 1 {
-		t.Error("Deposit not inserted")
-	}
+	assert.Equal(t, 1, len(dc.pendingDeposits), "Deposit not inserted")
 }

 func TestInsertPendingDeposit_ignoresNilDeposit(t *testing.T) {
 	dc := DepositCache{}
 	dc.InsertPendingDeposit(context.Background(), nil /*deposit*/, 0 /*blockNum*/, 0, [32]byte{})

-	if len(dc.pendingDeposits) > 0 {
-		t.Error("Unexpected deposit insertion")
-	}
+	assert.Equal(t, 0, len(dc.pendingDeposits))
 }

 func TestRemovePendingDeposit_OK(t *testing.T) {
 	db := DepositCache{}
-	proof1 := make([][]byte, 33)
+	proof1 := makeDepositProof()
 	proof1[0] = bytesutil.PadTo([]byte{'A'}, 32)
-	proof2 := make([][]byte, 33)
+	proof2 := makeDepositProof()
 	proof2[0] = bytesutil.PadTo([]byte{'A'}, 32)
-	depToRemove := &ethpb.Deposit{Proof: proof1}
-	otherDep := &ethpb.Deposit{Proof: proof2}
+	data := &ethpb.Deposit_Data{
+		PublicKey:             make([]byte, 48),
+		WithdrawalCredentials: make([]byte, 32),
+		Amount:                0,
+		Signature:             make([]byte, 96),
+	}
+	depToRemove := &ethpb.Deposit{Proof: proof1, Data: data}
+	otherDep := &ethpb.Deposit{Proof: proof2, Data: data}
 	db.pendingDeposits = []*dbpb.DepositContainer{
 		{Deposit: depToRemove, Index: 1},
 		{Deposit: otherDep, Index: 5},
@@ -55,21 +57,23 @@ func TestRemovePendingDeposit_IgnoresNilDeposit(t *testing.T) {
 	dc := DepositCache{}
 	dc.pendingDeposits = []*dbpb.DepositContainer{{Deposit: &ethpb.Deposit{}}}
 	dc.RemovePendingDeposit(context.Background(), nil /*deposit*/)
-	if len(dc.pendingDeposits) != 1 {
-		t.Errorf("Deposit unexpectedly removed")
-	}
+	assert.Equal(t, 1, len(dc.pendingDeposits), "Deposit unexpectedly removed")
 }

 func TestPendingDeposit_RoundTrip(t *testing.T) {
 	dc := DepositCache{}
-	proof := make([][]byte, 33)
+	proof := makeDepositProof()
 	proof[0] = bytesutil.PadTo([]byte{'A'}, 32)
-	dep := &ethpb.Deposit{Proof: proof}
+	data := &ethpb.Deposit_Data{
+		PublicKey:             make([]byte, 48),
+		WithdrawalCredentials: make([]byte, 32),
+		Amount:                0,
+		Signature:             make([]byte, 96),
+	}
+	dep := &ethpb.Deposit{Proof: proof, Data: data}
 	dc.InsertPendingDeposit(context.Background(), dep, 111, 100, [32]byte{})
 	dc.RemovePendingDeposit(context.Background(), dep)
-	if len(dc.pendingDeposits) != 0 {
-		t.Error("Failed to insert & delete a pending deposit")
-	}
+	assert.Equal(t, 0, len(dc.pendingDeposits), "Failed to insert & delete a pending deposit")
 }

 func TestPendingDeposits_OK(t *testing.T) {
@@ -86,15 +90,10 @@ func TestPendingDeposits_OK(t *testing.T) {
 		{Proof: [][]byte{[]byte("A")}},
 		{Proof: [][]byte{[]byte("B")}},
 	}
-
-	if !reflect.DeepEqual(deposits, expected) {
-		t.Errorf("Unexpected deposits. got=%+v want=%+v", deposits, expected)
-	}
+	assert.DeepEqual(t, expected, deposits)

 	all := dc.PendingDeposits(context.Background(), nil)
-	if len(all) != len(dc.pendingDeposits) {
-		t.Error("PendingDeposits(ctx, nil) did not return all deposits")
-	}
+	assert.Equal(t, len(dc.pendingDeposits), len(all), "PendingDeposits(ctx, nil) did not return all deposits")
 }

 func TestPrunePendingDeposits_ZeroMerkleIndex(t *testing.T) {
@@ -118,9 +117,7 @@ func TestPrunePendingDeposits_ZeroMerkleIndex(t *testing.T) {
 		{Eth1BlockHeight: 10, Index: 10},
 		{Eth1BlockHeight: 12, Index: 12},
 	}
-	if !reflect.DeepEqual(dc.pendingDeposits, expected) {
-		t.Errorf("Unexpected deposits. got=%+v want=%+v", dc.pendingDeposits, expected)
-	}
+	assert.DeepEqual(t, expected, dc.pendingDeposits)
 }

 func TestPrunePendingDeposits_OK(t *testing.T) {
@@ -143,9 +140,7 @@ func TestPrunePendingDeposits_OK(t *testing.T) {
 		{Eth1BlockHeight: 12, Index: 12},
 	}

-	if !reflect.DeepEqual(dc.pendingDeposits, expected) {
-		t.Errorf("Unexpected deposits. got=%+v want=%+v", dc.pendingDeposits, expected)
-	}
+	assert.DeepEqual(t, expected, dc.pendingDeposits)

 	dc.pendingDeposits = []*dbpb.DepositContainer{
 		{Eth1BlockHeight: 2, Index: 2},
@@ -162,8 +157,5 @@ func TestPrunePendingDeposits_OK(t *testing.T) {
 		{Eth1BlockHeight: 12, Index: 12},
 	}

-	if !reflect.DeepEqual(dc.pendingDeposits, expected) {
-		t.Errorf("Unexpected deposits. got=%+v want=%+v", dc.pendingDeposits, expected)
-	}
-
+	assert.DeepEqual(t, expected, dc.pendingDeposits)
 }
--- a/beacon-chain/cache/feature_flag_test.go
+++ b/beacon-chain/cache/feature_flag_test.go
@@ -1,14 +0,0 @@
-package cache
-
-import (
-	"os"
-	"testing"
-
-	"github.com/prysmaticlabs/prysm/shared/featureconfig"
-)
-
-func TestMain(m *testing.M) {
-	resetCfg := featureconfig.InitWithReset(&featureconfig.Flags{EnableEth1DataVoteCache: true})
-	defer resetCfg()
-	os.Exit(m.Run())
-}
--- a/beacon-chain/cache/hot_state_cache_test.go
+++ b/beacon-chain/cache/hot_state_cache_test.go
@@ -1,46 +0,0 @@
-package cache_test
-
-import (
-	"reflect"
-	"testing"
-
-	"github.com/prysmaticlabs/prysm/beacon-chain/cache"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
-	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
-)
-
-func TestHotStateCache_RoundTrip(t *testing.T) {
-	c := cache.NewHotStateCache()
-	root := [32]byte{'A'}
-	state := c.Get(root)
-	if state != nil {
-		t.Errorf("Empty cache returned an object: %v", state)
-	}
-	if c.Has(root) {
-		t.Error("Empty cache has an object")
-	}
-
-	state, err := stateTrie.InitializeFromProto(&pb.BeaconState{
-		Slot: 10,
-	})
-	if err != nil {
-		t.Fatal(err)
-	}
-	c.Put(root, state)
-
-	if !c.Has(root) {
-		t.Error("Empty cache does not have an object")
-	}
-	res := c.Get(root)
-	if state == nil {
-		t.Errorf("Empty cache returned an object: %v", state)
-	}
-	if !reflect.DeepEqual(state.CloneInnerState(), res.CloneInnerState()) {
-		t.Error("Expected equal protos to return from cache")
-	}
-
-	c.Delete(root)
-	if c.Has(root) {
-		t.Error("Cache not suppose to have the object")
-	}
-}
--- a/beacon-chain/cache/proposer_indices.go
+++ b/beacon-chain/cache/proposer_indices.go
@@ -0,0 +1,100 @@
+// +build !libfuzzer
+
+package cache
+
+import (
+	"sync"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+	types "github.com/prysmaticlabs/eth2-types"
+	"k8s.io/client-go/tools/cache"
+)
+
+var (
+	// maxProposerIndicesCacheSize defines the max number of proposer indices on per block root basis can cache.
+	// Due to reorgs and long finality, it's good to keep the old cache around for quickly switch over.
+	maxProposerIndicesCacheSize = uint64(8)
+
+	// ProposerIndicesCacheMiss tracks the number of proposerIndices requests that aren't present in the cache.
+	ProposerIndicesCacheMiss = promauto.NewCounter(prometheus.CounterOpts{
+		Name: "proposer_indices_cache_miss",
+		Help: "The number of proposer indices requests that aren't present in the cache.",
+	})
+	// ProposerIndicesCacheHit tracks the number of proposerIndices requests that are in the cache.
+	ProposerIndicesCacheHit = promauto.NewCounter(prometheus.CounterOpts{
+		Name: "proposer_indices_cache_hit",
+		Help: "The number of proposer indices requests that are present in the cache.",
+	})
+)
+
+// ProposerIndicesCache is a struct with 1 queue for looking up proposer indices by root.
+type ProposerIndicesCache struct {
+	ProposerIndicesCache *cache.FIFO
+	lock                 sync.RWMutex
+}
+
+// proposerIndicesKeyFn takes the block root as the key to retrieve proposer indices in a given epoch.
+func proposerIndicesKeyFn(obj interface{}) (string, error) {
+	info, ok := obj.(*ProposerIndices)
+	if !ok {
+		return "", ErrNotProposerIndices
+	}
+
+	return key(info.BlockRoot), nil
+}
+
+// NewProposerIndicesCache creates a new proposer indices cache for storing/accessing proposer index assignments of an epoch.
+func NewProposerIndicesCache() *ProposerIndicesCache {
+	return &ProposerIndicesCache{
+		ProposerIndicesCache: cache.NewFIFO(proposerIndicesKeyFn),
+	}
+}
+
+// AddProposerIndices adds ProposerIndices object to the cache.
+// This method also trims the least recently list if the cache size has ready the max cache size limit.
+func (c *ProposerIndicesCache) AddProposerIndices(p *ProposerIndices) error {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+
+	if err := c.ProposerIndicesCache.AddIfNotPresent(p); err != nil {
+		return err
+	}
+	trim(c.ProposerIndicesCache, maxProposerIndicesCacheSize)
+	return nil
+}
+
+// HasProposerIndices returns the proposer indices of a block root seed.
+func (c *ProposerIndicesCache) HasProposerIndices(r [32]byte) (bool, error) {
+	c.lock.RLock()
+	defer c.lock.RUnlock()
+	_, exists, err := c.ProposerIndicesCache.GetByKey(key(r))
+	if err != nil {
+		return false, err
+	}
+	return exists, nil
+}
+
+// ProposerIndices returns the proposer indices of a block root seed.
+func (c *ProposerIndicesCache) ProposerIndices(r [32]byte) ([]types.ValidatorIndex, error) {
+	c.lock.RLock()
+	defer c.lock.RUnlock()
+	obj, exists, err := c.ProposerIndicesCache.GetByKey(key(r))
+	if err != nil {
+		return nil, err
+	}
+
+	if exists {
+		ProposerIndicesCacheHit.Inc()
+	} else {
+		ProposerIndicesCacheMiss.Inc()
+		return nil, nil
+	}
+
+	item, ok := obj.(*ProposerIndices)
+	if !ok {
+		return nil, ErrNotProposerIndices
+	}
+
+	return item.ProposerIndices, nil
+}
--- a/beacon-chain/cache/proposer_indices_disabled.go
+++ b/beacon-chain/cache/proposer_indices_disabled.go
@@ -0,0 +1,31 @@
+// +build libfuzzer
+
+// This file is used in fuzzer builds to bypass proposer indices caches.
+package cache
+
+import types "github.com/prysmaticlabs/eth2-types"
+
+// FakeProposerIndicesCache is a struct with 1 queue for looking up proposer indices by root.
+type FakeProposerIndicesCache struct {
+}
+
+// NewProposerIndicesCache creates a new proposer indices cache for storing/accessing proposer index assignments of an epoch.
+func NewProposerIndicesCache() *FakeProposerIndicesCache {
+	return &FakeProposerIndicesCache{}
+}
+
+// AddProposerIndices adds ProposerIndices object to the cache.
+// This method also trims the least recently list if the cache size has ready the max cache size limit.
+func (c *FakeProposerIndicesCache) AddProposerIndices(p *ProposerIndices) error {
+	return nil
+}
+
+// ProposerIndices returns the proposer indices of a block root seed.
+func (c *FakeProposerIndicesCache) ProposerIndices(r [32]byte) ([]types.ValidatorIndex, error) {
+	return nil, nil
+}
+
+// HasProposerIndices returns the proposer indices of a block root seed.
+func (c *FakeProposerIndicesCache) HasProposerIndices(r [32]byte) (bool, error) {
+	return false, nil
+}
--- a/beacon-chain/cache/proposer_indices_test.go
+++ b/beacon-chain/cache/proposer_indices_test.go
@@ -0,0 +1,74 @@
+package cache
+
+import (
+	"strconv"
+	"testing"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+)
+
+func TestProposerKeyFn_OK(t *testing.T) {
+	item := &ProposerIndices{
+		BlockRoot:       [32]byte{'A'},
+		ProposerIndices: []types.ValidatorIndex{1, 2, 3, 4, 5},
+	}
+
+	k, err := proposerIndicesKeyFn(item)
+	require.NoError(t, err)
+	assert.Equal(t, key(item.BlockRoot), k)
+}
+
+func TestProposerKeyFn_InvalidObj(t *testing.T) {
+	_, err := proposerIndicesKeyFn("bad")
+	assert.Equal(t, ErrNotProposerIndices, err)
+}
+
+func TestProposerCache_AddProposerIndicesList(t *testing.T) {
+	cache := NewProposerIndicesCache()
+	bRoot := [32]byte{'A'}
+	indices, err := cache.ProposerIndices(bRoot)
+	require.NoError(t, err)
+	if indices != nil {
+		t.Error("Expected committee count not to exist in empty cache")
+	}
+	has, err := cache.HasProposerIndices(bRoot)
+	require.NoError(t, err)
+	assert.Equal(t, false, has)
+	require.NoError(t, cache.AddProposerIndices(&ProposerIndices{
+		ProposerIndices: indices,
+		BlockRoot:       bRoot,
+	}))
+
+	received, err := cache.ProposerIndices(bRoot)
+	require.NoError(t, err)
+	assert.DeepEqual(t, received, indices)
+	has, err = cache.HasProposerIndices(bRoot)
+	require.NoError(t, err)
+	assert.Equal(t, true, has)
+
+	item := &ProposerIndices{BlockRoot: [32]byte{'B'}, ProposerIndices: []types.ValidatorIndex{1, 2, 3, 4, 5, 6}}
+	require.NoError(t, cache.AddProposerIndices(item))
+
+	received, err = cache.ProposerIndices(item.BlockRoot)
+	require.NoError(t, err)
+	assert.DeepEqual(t, item.ProposerIndices, received)
+	has, err = cache.HasProposerIndices(bRoot)
+	require.NoError(t, err)
+	assert.Equal(t, true, has)
+
+}
+
+func TestProposerCache_CanRotate(t *testing.T) {
+	cache := NewProposerIndicesCache()
+	for i := 0; i < int(maxProposerIndicesCacheSize)+1; i++ {
+		s := []byte(strconv.Itoa(i))
+		item := &ProposerIndices{BlockRoot: bytesutil.ToBytes32(s)}
+		require.NoError(t, cache.AddProposerIndices(item))
+	}
+
+	k := cache.ProposerIndicesCache.ListKeys()
+	assert.Equal(t, maxProposerIndicesCacheSize, uint64(len(k)))
+}
--- a/beacon-chain/cache/proposer_indices_type.go
+++ b/beacon-chain/cache/proposer_indices_type.go
@@ -0,0 +1,17 @@
+package cache
+
+import (
+	"errors"
+
+	types "github.com/prysmaticlabs/eth2-types"
+)
+
+// ErrNotProposerIndices will be returned when a cache object is not a pointer to
+// a ProposerIndices struct.
+var ErrNotProposerIndices = errors.New("object is not a proposer indices struct")
+
+// ProposerIndices defines the cached struct for proposer indices.
+type ProposerIndices struct {
+	BlockRoot       [32]byte
+	ProposerIndices []types.ValidatorIndex
+}
--- a/beacon-chain/cache/skip_slot_cache.go
+++ b/beacon-chain/cache/skip_slot_cache.go
@@ -9,7 +9,7 @@ import (
 	lru "github.com/hashicorp/golang-lru"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
 	"go.opencensus.io/trace"
 )

@@ -30,7 +30,7 @@ type SkipSlotCache struct {
 	cache      *lru.Cache
 	lock       sync.RWMutex
 	disabled   bool // Allow for programmatic toggling of the cache, useful during initial sync.
-	inProgress map[uint64]bool
+	inProgress map[[32]byte]bool
 }

 // NewSkipSlotCache initializes the map and underlying cache.
@@ -41,7 +41,7 @@ func NewSkipSlotCache() *SkipSlotCache {
 	}
 	return &SkipSlotCache{
 		cache:      cache,
-		inProgress: make(map[uint64]bool),
+		inProgress: make(map[[32]byte]bool),
 	}
 }

@@ -57,7 +57,7 @@ func (c *SkipSlotCache) Disable() {

 // Get waits for any in progress calculation to complete before returning a
 // cached response, if any.
-func (c *SkipSlotCache) Get(ctx context.Context, slot uint64) (*stateTrie.BeaconState, error) {
+func (c *SkipSlotCache) Get(ctx context.Context, r [32]byte) (iface.BeaconState, error) {
 	ctx, span := trace.StartSpan(ctx, "skipSlotCache.Get")
 	defer span.End()
 	if c.disabled {
@@ -77,7 +77,7 @@ func (c *SkipSlotCache) Get(ctx context.Context, slot uint64) (*stateTrie.Beacon
 		}

 		c.lock.RLock()
-		if !c.inProgress[slot] {
+		if !c.inProgress[r] {
 			c.lock.RUnlock()
 			break
 		}
@@ -92,12 +92,12 @@ func (c *SkipSlotCache) Get(ctx context.Context, slot uint64) (*stateTrie.Beacon
 	}
 	span.AddAttributes(trace.BoolAttribute("inProgress", inProgress))

-	item, exists := c.cache.Get(slot)
+	item, exists := c.cache.Get(r)

 	if exists && item != nil {
 		skipSlotCacheHit.Inc()
 		span.AddAttributes(trace.BoolAttribute("hit", true))
-		return item.(*stateTrie.BeaconState).Copy(), nil
+		return item.(iface.BeaconState).Copy(), nil
 	}
 	skipSlotCacheMiss.Inc()
 	span.AddAttributes(trace.BoolAttribute("hit", false))
@@ -106,7 +106,7 @@ func (c *SkipSlotCache) Get(ctx context.Context, slot uint64) (*stateTrie.Beacon

 // MarkInProgress a request so that any other similar requests will block on
 // Get until MarkNotInProgress is called.
-func (c *SkipSlotCache) MarkInProgress(slot uint64) error {
+func (c *SkipSlotCache) MarkInProgress(r [32]byte) error {
 	if c.disabled {
 		return nil
 	}
@@ -114,16 +114,16 @@ func (c *SkipSlotCache) MarkInProgress(slot uint64) error {
 	c.lock.Lock()
 	defer c.lock.Unlock()

-	if c.inProgress[slot] {
+	if c.inProgress[r] {
 		return ErrAlreadyInProgress
 	}
-	c.inProgress[slot] = true
+	c.inProgress[r] = true
 	return nil
 }

 // MarkNotInProgress will release the lock on a given request. This should be
 // called after put.
-func (c *SkipSlotCache) MarkNotInProgress(slot uint64) error {
+func (c *SkipSlotCache) MarkNotInProgress(r [32]byte) error {
 	if c.disabled {
 		return nil
 	}
@@ -131,18 +131,18 @@ func (c *SkipSlotCache) MarkNotInProgress(slot uint64) error {
 	c.lock.Lock()
 	defer c.lock.Unlock()

-	delete(c.inProgress, slot)
+	delete(c.inProgress, r)
 	return nil
 }

 // Put the response in the cache.
-func (c *SkipSlotCache) Put(ctx context.Context, slot uint64, state *stateTrie.BeaconState) error {
+func (c *SkipSlotCache) Put(_ context.Context, r [32]byte, state iface.BeaconState) error {
 	if c.disabled {
 		return nil
 	}

 	// Copy state so cached value is not mutated.
-	c.cache.Add(slot, state.Copy())
+	c.cache.Add(r, state.Copy())

 	return nil
 }
--- a/beacon-chain/cache/skip_slot_cache_test.go
+++ b/beacon-chain/cache/skip_slot_cache_test.go
@@ -2,52 +2,36 @@ package cache_test

 import (
 	"context"
-	"reflect"
 	"testing"

 	"github.com/prysmaticlabs/prysm/beacon-chain/cache"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateV0"
 	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 )

 func TestSkipSlotCache_RoundTrip(t *testing.T) {
 	ctx := context.Background()
 	c := cache.NewSkipSlotCache()

-	state, err := c.Get(ctx, 5)
-	if err != nil {
-		t.Error(err)
-	}
+	r := [32]byte{'a'}
+	state, err := c.Get(ctx, r)
+	require.NoError(t, err)
+	assert.Equal(t, iface.BeaconState(nil), state, "Empty cache returned an object")

-	if state != nil {
-		t.Errorf("Empty cache returned an object: %v", state)
-	}
+	require.NoError(t, c.MarkInProgress(r))

-	if err := c.MarkInProgress(5); err != nil {
-		t.Error(err)
-	}
-
-	state, err = stateTrie.InitializeFromProto(&pb.BeaconState{
+	state, err = stateV0.InitializeFromProto(&pb.BeaconState{
 		Slot: 10,
 	})
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)

-	if err = c.Put(ctx, 5, state); err != nil {
-		t.Error(err)
-	}
+	require.NoError(t, c.Put(ctx, r, state))
+	require.NoError(t, c.MarkNotInProgress(r))

-	if err := c.MarkNotInProgress(5); err != nil {
-		t.Error(err)
-	}
-
-	res, err := c.Get(ctx, 5)
-	if err != nil {
-		t.Error(err)
-	}
-
-	if !reflect.DeepEqual(state.CloneInnerState(), res.CloneInnerState()) {
-		t.Error("Expected equal protos to return from cache")
-	}
+	res, err := c.Get(ctx, r)
+	require.NoError(t, err)
+	assert.DeepEqual(t, res.CloneInnerState(), state.CloneInnerState(), "Expected equal protos to return from cache")
 }
--- a/beacon-chain/cache/state_summary.go
+++ b/beacon-chain/cache/state_summary.go
@@ -1,65 +0,0 @@
-package cache
-
-import (
-	"sync"
-
-	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
-)
-
-// StateSummaryCache caches state summary object.
-type StateSummaryCache struct {
-	initSyncStateSummaries     map[[32]byte]*pb.StateSummary
-	initSyncStateSummariesLock sync.RWMutex
-}
-
-// NewStateSummaryCache creates a new state summary cache.
-func NewStateSummaryCache() *StateSummaryCache {
-	return &StateSummaryCache{
-		initSyncStateSummaries: make(map[[32]byte]*pb.StateSummary),
-	}
-}
-
-// Put saves a state summary to the initial sync state summaries cache.
-func (s *StateSummaryCache) Put(r [32]byte, b *pb.StateSummary) {
-	s.initSyncStateSummariesLock.Lock()
-	defer s.initSyncStateSummariesLock.Unlock()
-	s.initSyncStateSummaries[r] = b
-}
-
-// Has checks if a state summary exists in the initial sync state summaries cache using the root
-// of the block.
-func (s *StateSummaryCache) Has(r [32]byte) bool {
-	s.initSyncStateSummariesLock.RLock()
-	defer s.initSyncStateSummariesLock.RUnlock()
-	_, ok := s.initSyncStateSummaries[r]
-	return ok
-}
-
-// Get retrieves a state summary from the initial sync state summaries cache using the root of
-// the block.
-func (s *StateSummaryCache) Get(r [32]byte) *pb.StateSummary {
-	s.initSyncStateSummariesLock.RLock()
-	defer s.initSyncStateSummariesLock.RUnlock()
-	b := s.initSyncStateSummaries[r]
-	return b
-}
-
-// GetAll retrieves all the beacon state summaries from the initial sync state summaries cache, the returned
-// state summaries are unordered.
-func (s *StateSummaryCache) GetAll() []*pb.StateSummary {
-	s.initSyncStateSummariesLock.RLock()
-	defer s.initSyncStateSummariesLock.RUnlock()
-
-	blks := make([]*pb.StateSummary, 0, len(s.initSyncStateSummaries))
-	for _, b := range s.initSyncStateSummaries {
-		blks = append(blks, b)
-	}
-	return blks
-}
-
-// Clear clears out the initial sync state summaries cache.
-func (s *StateSummaryCache) Clear() {
-	s.initSyncStateSummariesLock.Lock()
-	defer s.initSyncStateSummariesLock.Unlock()
-	s.initSyncStateSummaries = make(map[[32]byte]*pb.StateSummary)
-}
--- a/beacon-chain/cache/subnet_ids.go
+++ b/beacon-chain/cache/subnet_ids.go
@@ -6,6 +6,7 @@ import (

 	lru "github.com/hashicorp/golang-lru"
 	"github.com/patrickmn/go-cache"
+	types "github.com/prysmaticlabs/eth2-types"
 	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/prysmaticlabs/prysm/shared/sliceutil"
 )
@@ -25,40 +26,40 @@ var SubnetIDs = newSubnetIDs()
 func newSubnetIDs() *subnetIDs {
 	// Given a node can calculate committee assignments of current epoch and next epoch.
 	// Max size is set to 2 epoch length.
-	cacheSize := params.BeaconConfig().MaxCommitteesPerSlot * params.BeaconConfig().SlotsPerEpoch * 2
-	attesterCache, err := lru.New(int(cacheSize))
+	cacheSize := int(params.BeaconConfig().SlotsPerEpoch.Mul(params.BeaconConfig().MaxCommitteesPerSlot * 2))
+	attesterCache, err := lru.New(cacheSize)
 	if err != nil {
 		panic(err)
 	}
-	aggregatorCache, err := lru.New(int(cacheSize))
+	aggregatorCache, err := lru.New(cacheSize)
 	if err != nil {
 		panic(err)
 	}
-	epochDuration := time.Duration(params.BeaconConfig().SlotsPerEpoch * params.BeaconConfig().SecondsPerSlot)
-	subLength := epochDuration * time.Duration(params.BeaconNetworkConfig().EpochsPerRandomSubnetSubscription)
+	epochDuration := time.Duration(params.BeaconConfig().SlotsPerEpoch.Mul(params.BeaconConfig().SecondsPerSlot))
+	subLength := epochDuration * time.Duration(params.BeaconConfig().EpochsPerRandomSubnetSubscription)
 	persistentCache := cache.New(subLength*time.Second, epochDuration*time.Second)
 	return &subnetIDs{attester: attesterCache, aggregator: aggregatorCache, persistentSubnets: persistentCache}
 }

 // AddAttesterSubnetID adds the subnet index for subscribing subnet for the attester of a given slot.
-func (c *subnetIDs) AddAttesterSubnetID(slot uint64, subnetID uint64) {
-	c.attesterLock.Lock()
-	defer c.attesterLock.Unlock()
+func (s *subnetIDs) AddAttesterSubnetID(slot types.Slot, subnetID uint64) {
+	s.attesterLock.Lock()
+	defer s.attesterLock.Unlock()

 	ids := []uint64{subnetID}
-	val, exists := c.attester.Get(slot)
+	val, exists := s.attester.Get(slot)
 	if exists {
 		ids = sliceutil.UnionUint64(append(val.([]uint64), ids...))
 	}
-	c.attester.Add(slot, ids)
+	s.attester.Add(slot, ids)
 }

 // GetAttesterSubnetIDs gets the subnet IDs for subscribed subnets for attesters of the slot.
-func (c *subnetIDs) GetAttesterSubnetIDs(slot uint64) []uint64 {
-	c.attesterLock.RLock()
-	defer c.attesterLock.RUnlock()
+func (s *subnetIDs) GetAttesterSubnetIDs(slot types.Slot) []uint64 {
+	s.attesterLock.RLock()
+	defer s.attesterLock.RUnlock()

-	val, exists := c.attester.Get(slot)
+	val, exists := s.attester.Get(slot)
 	if !exists {
 		return nil
 	}
@@ -69,24 +70,24 @@ func (c *subnetIDs) GetAttesterSubnetIDs(slot uint64) []uint64 {
 }

 // AddAggregatorSubnetID adds the subnet ID for subscribing subnet for the aggregator of a given slot.
-func (c *subnetIDs) AddAggregatorSubnetID(slot uint64, subnetID uint64) {
-	c.aggregatorLock.Lock()
-	defer c.aggregatorLock.Unlock()
+func (s *subnetIDs) AddAggregatorSubnetID(slot types.Slot, subnetID uint64) {
+	s.aggregatorLock.Lock()
+	defer s.aggregatorLock.Unlock()

 	ids := []uint64{subnetID}
-	val, exists := c.aggregator.Get(slot)
+	val, exists := s.aggregator.Get(slot)
 	if exists {
 		ids = sliceutil.UnionUint64(append(val.([]uint64), ids...))
 	}
-	c.aggregator.Add(slot, ids)
+	s.aggregator.Add(slot, ids)
 }

 // GetAggregatorSubnetIDs gets the subnet IDs for subscribing subnet for aggregator of the slot.
-func (c *subnetIDs) GetAggregatorSubnetIDs(slot uint64) []uint64 {
-	c.aggregatorLock.RLock()
-	defer c.aggregatorLock.RUnlock()
+func (s *subnetIDs) GetAggregatorSubnetIDs(slot types.Slot) []uint64 {
+	s.aggregatorLock.RLock()
+	defer s.aggregatorLock.RUnlock()

-	val, exists := c.aggregator.Get(slot)
+	val, exists := s.aggregator.Get(slot)
 	if !exists {
 		return []uint64{}
 	}
@@ -95,11 +96,11 @@ func (c *subnetIDs) GetAggregatorSubnetIDs(slot uint64) []uint64 {

 // GetPersistentSubnets retrieves the persistent subnet and expiration time of that validator's
 // subscription.
-func (c *subnetIDs) GetPersistentSubnets(pubkey []byte) ([]uint64, bool, time.Time) {
-	c.subnetsLock.RLock()
-	defer c.subnetsLock.RUnlock()
+func (s *subnetIDs) GetPersistentSubnets(pubkey []byte) ([]uint64, bool, time.Time) {
+	s.subnetsLock.RLock()
+	defer s.subnetsLock.RUnlock()

-	id, duration, ok := c.persistentSubnets.GetWithExpiration(string(pubkey))
+	id, duration, ok := s.persistentSubnets.GetWithExpiration(string(pubkey))
 	if !ok {
 		return []uint64{}, ok, time.Time{}
 	}
@@ -108,12 +109,12 @@ func (c *subnetIDs) GetPersistentSubnets(pubkey []byte) ([]uint64, bool, time.Ti

 // GetAllSubnets retrieves all the non-expired subscribed subnets of all the validators
 // in the cache.
-func (c *subnetIDs) GetAllSubnets() []uint64 {
-	c.subnetsLock.RLock()
-	defer c.subnetsLock.RUnlock()
+func (s *subnetIDs) GetAllSubnets() []uint64 {
+	s.subnetsLock.RLock()
+	defer s.subnetsLock.RUnlock()

-	itemsMap := c.persistentSubnets.Items()
-	committees := []uint64{}
+	itemsMap := s.persistentSubnets.Items()
+	var committees []uint64

 	for _, v := range itemsMap {
 		if v.Expired() {
@@ -126,9 +127,28 @@ func (c *subnetIDs) GetAllSubnets() []uint64 {

 // AddPersistentCommittee adds the relevant committee for that particular validator along with its
 // expiration period.
-func (c *subnetIDs) AddPersistentCommittee(pubkey []byte, comIndex []uint64, duration time.Duration) {
-	c.subnetsLock.Lock()
-	defer c.subnetsLock.Unlock()
+func (s *subnetIDs) AddPersistentCommittee(pubkey []byte, comIndex []uint64, duration time.Duration) {
+	s.subnetsLock.Lock()
+	defer s.subnetsLock.Unlock()

-	c.persistentSubnets.Set(string(pubkey), comIndex, duration)
+	s.persistentSubnets.Set(string(pubkey), comIndex, duration)
+}
+
+// EmptyAllCaches empties out all the related caches and flushes any stored
+// entries on them. This should only ever be used for testing, in normal
+// production, handling of the relevant subnets for each role is done
+// separately.
+func (s *subnetIDs) EmptyAllCaches() {
+	// Clear the caches.
+	s.attesterLock.Lock()
+	s.attester.Purge()
+	s.attesterLock.Unlock()
+
+	s.aggregatorLock.Lock()
+	s.aggregator.Purge()
+	s.aggregatorLock.Unlock()
+
+	s.subnetsLock.Lock()
+	s.persistentSubnets.Flush()
+	s.subnetsLock.Unlock()
 }
--- a/beacon-chain/cache/subnet_ids_test.go
+++ b/beacon-chain/cache/subnet_ids_test.go
@@ -1,67 +1,52 @@
 package cache

 import (
-	"reflect"
 	"testing"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 )

 func TestSubnetIDsCache_RoundTrip(t *testing.T) {
 	c := newSubnetIDs()
-	slot := uint64(100)
+	slot := types.Slot(100)
 	committeeIDs := c.GetAggregatorSubnetIDs(slot)
-	if len(committeeIDs) != 0 {
-		t.Errorf("Empty cache returned an object: %v", committeeIDs)
-	}
+	assert.Equal(t, 0, len(committeeIDs), "Empty cache returned an object")

 	c.AddAggregatorSubnetID(slot, 1)
 	res := c.GetAggregatorSubnetIDs(slot)
-	if !reflect.DeepEqual(res, []uint64{1}) {
-		t.Error("Expected equal value to return from cache")
-	}
+	assert.DeepEqual(t, []uint64{1}, res)

 	c.AddAggregatorSubnetID(slot, 2)
 	res = c.GetAggregatorSubnetIDs(slot)
-	if !reflect.DeepEqual(res, []uint64{1, 2}) {
-		t.Error("Expected equal value to return from cache")
-	}
+	assert.DeepEqual(t, []uint64{1, 2}, res)

 	c.AddAggregatorSubnetID(slot, 3)
 	res = c.GetAggregatorSubnetIDs(slot)
-	if !reflect.DeepEqual(res, []uint64{1, 2, 3}) {
-		t.Error("Expected equal value to return from cache")
-	}
+	assert.DeepEqual(t, []uint64{1, 2, 3}, res)

 	committeeIDs = c.GetAttesterSubnetIDs(slot)
-	if len(committeeIDs) != 0 {
-		t.Errorf("Empty cache returned an object: %v", committeeIDs)
-	}
+	assert.Equal(t, 0, len(committeeIDs), "Empty cache returned an object")

 	c.AddAttesterSubnetID(slot, 11)
 	res = c.GetAttesterSubnetIDs(slot)
-	if !reflect.DeepEqual(res, []uint64{11}) {
-		t.Error("Expected equal value to return from cache")
-	}
+	assert.DeepEqual(t, []uint64{11}, res)

 	c.AddAttesterSubnetID(slot, 22)
 	res = c.GetAttesterSubnetIDs(slot)
-	if !reflect.DeepEqual(res, []uint64{11, 22}) {
-		t.Error("Expected equal value to return from cache")
-	}
+	assert.DeepEqual(t, []uint64{11, 22}, res)

 	c.AddAttesterSubnetID(slot, 33)
 	res = c.GetAttesterSubnetIDs(slot)
-	if !reflect.DeepEqual(res, []uint64{11, 22, 33}) {
-		t.Error("Expected equal value to return from cache")
-	}
+	assert.DeepEqual(t, []uint64{11, 22, 33}, res)
 }

 func TestSubnetIDsCache_PersistentCommitteeRoundtrip(t *testing.T) {
-	pubkeySet := [][48]byte{}
 	c := newSubnetIDs()

 	for i := 0; i < 20; i++ {
 		pubkey := [48]byte{byte(i)}
-		pubkeySet = append(pubkeySet, pubkey)
 		c.AddPersistentCommittee(pubkey[:], []uint64{uint64(i)}, 0)
 	}

@@ -73,12 +58,8 @@ func TestSubnetIDsCache_PersistentCommitteeRoundtrip(t *testing.T) {
 			t.Errorf("Couldn't find entry in cache for pubkey %#x", pubkey)
 			continue
 		}
-		if idxs[0] != i {
-			t.Fatalf("Wanted index of %d but got %d", i, idxs[0])
-		}
+		require.Equal(t, i, idxs[0])
 	}
 	coms := c.GetAllSubnets()
-	if len(coms) != 20 {
-		t.Errorf("Number of committees is not %d but is %d", 20, len(coms))
-	}
+	assert.Equal(t, 20, len(coms))
 }
--- a/beacon-chain/core/blocks/BUILD.bazel
+++ b/beacon-chain/core/blocks/BUILD.bazel
@@ -4,33 +4,45 @@ load("@io_bazel_rules_go//go:def.bzl", "go_test")
 go_library(
    name = "go_default_library",
    srcs = [
-        "block.go",
-        "block_operations.go",
+        "attestation.go",
+        "attester_slashing.go",
+        "deposit.go",
+        "eth1_data.go",
+        "exit.go",
+        "genesis.go",
+        "header.go",
+        "log.go",
+        "proposer_slashing.go",
+        "randao.go",
+        "signature.go",
    ],
    importpath = "github.com/prysmaticlabs/prysm/beacon-chain/core/blocks",
    visibility = [
        "//beacon-chain:__subpackages__",
        "//fuzz:__pkg__",
        "//shared/testutil:__pkg__",
+        "//validator/accounts:__pkg__",
    ],
    deps = [
        "//beacon-chain/core/helpers:go_default_library",
        "//beacon-chain/core/validators:go_default_library",
-        "//beacon-chain/state:go_default_library",
-        "//beacon-chain/state/stateutil:go_default_library",
+        "//beacon-chain/state/interface:go_default_library",
+        "//beacon-chain/state/stateV0:go_default_library",
        "//proto/beacon/p2p/v1:go_default_library",
        "//shared/attestationutil:go_default_library",
        "//shared/bls:go_default_library",
        "//shared/bytesutil:go_default_library",
+        "//shared/depositutil:go_default_library",
        "//shared/hashutil:go_default_library",
        "//shared/mathutil:go_default_library",
        "//shared/params:go_default_library",
+        "//shared/slashutil:go_default_library",
        "//shared/sliceutil:go_default_library",
        "//shared/trieutil:go_default_library",
        "@com_github_gogo_protobuf//proto:go_default_library",
        "@com_github_pkg_errors//:go_default_library",
+        "@com_github_prysmaticlabs_eth2_types//:go_default_library",
        "@com_github_prysmaticlabs_ethereumapis//eth/v1alpha1:go_default_library",
-        "@com_github_prysmaticlabs_go_ssz//:go_default_library",
        "@com_github_sirupsen_logrus//:go_default_library",
        "@io_opencensus_go//trace:go_default_library",
    ],
@@ -40,17 +52,29 @@ go_test(
    name = "go_default_test",
    size = "medium",
    srcs = [
+        "attestation_regression_test.go",
+        "attestation_test.go",
+        "attester_slashing_test.go",
        "block_operations_fuzz_test.go",
-        "block_operations_test.go",
        "block_regression_test.go",
-        "block_test.go",
+        "deposit_test.go",
        "eth1_data_test.go",
+        "exit_test.go",
+        "genesis_test.go",
+        "header_test.go",
+        "proposer_slashing_regression_test.go",
+        "proposer_slashing_test.go",
+        "randao_test.go",
    ],
+    data = glob(["testdata/**"]),
    embed = [":go_default_library"],
+    shard_count = 2,
    deps = [
        "//beacon-chain/core/helpers:go_default_library",
-        "//beacon-chain/state:go_default_library",
-        "//beacon-chain/state/stateutil:go_default_library",
+        "//beacon-chain/core/validators:go_default_library",
+        "//beacon-chain/p2p/types:go_default_library",
+        "//beacon-chain/state/interface:go_default_library",
+        "//beacon-chain/state/stateV0:go_default_library",
        "//proto/beacon/p2p/v1:go_default_library",
        "//shared/aggregation:go_default_library",
        "//shared/aggregation/attestations:go_default_library",
@@ -59,13 +83,14 @@ go_test(
        "//shared/bytesutil:go_default_library",
        "//shared/params:go_default_library",
        "//shared/testutil:go_default_library",
+        "//shared/testutil/assert:go_default_library",
+        "//shared/testutil/require:go_default_library",
        "//shared/trieutil:go_default_library",
        "@com_github_gogo_protobuf//proto:go_default_library",
        "@com_github_google_gofuzz//:go_default_library",
+        "@com_github_prysmaticlabs_eth2_types//:go_default_library",
        "@com_github_prysmaticlabs_ethereumapis//eth/v1alpha1:go_default_library",
        "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
-        "@com_github_prysmaticlabs_go_ssz//:go_default_library",
        "@com_github_sirupsen_logrus//:go_default_library",
-        "@in_gopkg_d4l3k_messagediff_v1//:go_default_library",
    ],
 )
--- a/beacon-chain/core/blocks/attestation.go
+++ b/beacon-chain/core/blocks/attestation.go
@@ -0,0 +1,287 @@
+package blocks
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/pkg/errors"
+	types "github.com/prysmaticlabs/eth2-types"
+	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
+	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
+	"github.com/prysmaticlabs/prysm/shared/attestationutil"
+	"github.com/prysmaticlabs/prysm/shared/bls"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"go.opencensus.io/trace"
+)
+
+// ProcessAttestations applies processing operations to a block's inner attestation
+// records.
+func ProcessAttestations(
+	ctx context.Context,
+	beaconState iface.BeaconState,
+	b *ethpb.SignedBeaconBlock,
+) (iface.BeaconState, error) {
+	if err := helpers.VerifyNilBeaconBlock(b); err != nil {
+		return nil, err
+	}
+
+	var err error
+	for idx, attestation := range b.Block.Body.Attestations {
+		beaconState, err = ProcessAttestation(ctx, beaconState, attestation)
+		if err != nil {
+			return nil, errors.Wrapf(err, "could not verify attestation at index %d in block", idx)
+		}
+	}
+	return beaconState, nil
+}
+
+// ProcessAttestation verifies an input attestation can pass through processing using the given beacon state.
+//
+// Spec pseudocode definition:
+//  def process_attestation(state: BeaconState, attestation: Attestation) -> None:
+//    data = attestation.data
+//    assert data.target.epoch in (get_previous_epoch(state), get_current_epoch(state))
+//    assert data.target.epoch == compute_epoch_at_slot(data.slot)
+//    assert data.slot + MIN_ATTESTATION_INCLUSION_DELAY <= state.slot <= data.slot + SLOTS_PER_EPOCH
+//    assert data.index < get_committee_count_per_slot(state, data.target.epoch)
+//
+//    committee = get_beacon_committee(state, data.slot, data.index)
+//    assert len(attestation.aggregation_bits) == len(committee)
+//
+//    pending_attestation = PendingAttestation(
+//        data=data,
+//        aggregation_bits=attestation.aggregation_bits,
+//        inclusion_delay=state.slot - data.slot,
+//        proposer_index=get_beacon_proposer_index(state),
+//    )
+//
+//    if data.target.epoch == get_current_epoch(state):
+//        assert data.source == state.current_justified_checkpoint
+//        state.current_epoch_attestations.append(pending_attestation)
+//    else:
+//        assert data.source == state.previous_justified_checkpoint
+//        state.previous_epoch_attestations.append(pending_attestation)
+//
+//    # Verify signature
+//    assert is_valid_indexed_attestation(state, get_indexed_attestation(state, attestation))
+func ProcessAttestation(
+	ctx context.Context,
+	beaconState iface.BeaconState,
+	att *ethpb.Attestation,
+) (iface.BeaconState, error) {
+	beaconState, err := ProcessAttestationNoVerifySignature(ctx, beaconState, att)
+	if err != nil {
+		return nil, err
+	}
+	return beaconState, VerifyAttestationSignature(ctx, beaconState, att)
+}
+
+// ProcessAttestationsNoVerifySignature applies processing operations to a block's inner attestation
+// records. The only difference would be that the attestation signature would not be verified.
+func ProcessAttestationsNoVerifySignature(
+	ctx context.Context,
+	beaconState iface.BeaconState,
+	b *ethpb.SignedBeaconBlock,
+) (iface.BeaconState, error) {
+	if err := helpers.VerifyNilBeaconBlock(b); err != nil {
+		return nil, err
+	}
+	body := b.Block.Body
+	var err error
+	for idx, attestation := range body.Attestations {
+		beaconState, err = ProcessAttestationNoVerifySignature(ctx, beaconState, attestation)
+		if err != nil {
+			return nil, errors.Wrapf(err, "could not verify attestation at index %d in block", idx)
+		}
+	}
+	return beaconState, nil
+}
+
+// VerifyAttestationNoVerifySignature verifies the attestation without verifying the attestation signature. This is
+// used before processing attestation with the beacon state.
+func VerifyAttestationNoVerifySignature(
+	ctx context.Context,
+	beaconState iface.ReadOnlyBeaconState,
+	att *ethpb.Attestation,
+) error {
+	ctx, span := trace.StartSpan(ctx, "core.VerifyAttestationNoVerifySignature")
+	defer span.End()
+
+	if err := helpers.ValidateNilAttestation(att); err != nil {
+		return err
+	}
+	currEpoch := helpers.CurrentEpoch(beaconState)
+	prevEpoch := helpers.PrevEpoch(beaconState)
+	data := att.Data
+	if data.Target.Epoch != prevEpoch && data.Target.Epoch != currEpoch {
+		return fmt.Errorf(
+			"expected target epoch (%d) to be the previous epoch (%d) or the current epoch (%d)",
+			data.Target.Epoch,
+			prevEpoch,
+			currEpoch,
+		)
+	}
+
+	if data.Target.Epoch == currEpoch {
+		if !beaconState.MatchCurrentJustifiedCheckpoint(data.Source) {
+			return errors.New("source check point not equal to current justified checkpoint")
+		}
+	} else {
+		if !beaconState.MatchPreviousJustifiedCheckpoint(data.Source) {
+			return errors.New("source check point not equal to previous justified checkpoint")
+		}
+	}
+
+	if err := helpers.ValidateSlotTargetEpoch(att.Data); err != nil {
+		return err
+	}
+
+	s := att.Data.Slot
+	minInclusionCheck := s+params.BeaconConfig().MinAttestationInclusionDelay <= beaconState.Slot()
+	epochInclusionCheck := beaconState.Slot() <= s+params.BeaconConfig().SlotsPerEpoch
+	if !minInclusionCheck {
+		return fmt.Errorf(
+			"attestation slot %d + inclusion delay %d > state slot %d",
+			s,
+			params.BeaconConfig().MinAttestationInclusionDelay,
+			beaconState.Slot(),
+		)
+	}
+	if !epochInclusionCheck {
+		return fmt.Errorf(
+			"state slot %d > attestation slot %d + SLOTS_PER_EPOCH %d",
+			beaconState.Slot(),
+			s,
+			params.BeaconConfig().SlotsPerEpoch,
+		)
+	}
+	activeValidatorCount, err := helpers.ActiveValidatorCount(beaconState, att.Data.Target.Epoch)
+	if err != nil {
+		return err
+	}
+	c := helpers.SlotCommitteeCount(activeValidatorCount)
+	if uint64(att.Data.CommitteeIndex) >= c {
+		return fmt.Errorf("committee index %d >= committee count %d", att.Data.CommitteeIndex, c)
+	}
+
+	if err := helpers.VerifyAttestationBitfieldLengths(beaconState, att); err != nil {
+		return errors.Wrap(err, "could not verify attestation bitfields")
+	}
+
+	// Verify attesting indices are correct.
+	committee, err := helpers.BeaconCommitteeFromState(beaconState, att.Data.Slot, att.Data.CommitteeIndex)
+	if err != nil {
+		return err
+	}
+	indexedAtt, err := attestationutil.ConvertToIndexed(ctx, att, committee)
+	if err != nil {
+		return err
+	}
+
+	return attestationutil.IsValidAttestationIndices(ctx, indexedAtt)
+}
+
+// ProcessAttestationNoVerifySignature processes the attestation without verifying the attestation signature. This
+// method is used to validate attestations whose signatures have already been verified.
+func ProcessAttestationNoVerifySignature(
+	ctx context.Context,
+	beaconState iface.BeaconState,
+	att *ethpb.Attestation,
+) (iface.BeaconState, error) {
+	ctx, span := trace.StartSpan(ctx, "core.ProcessAttestationNoVerifySignature")
+	defer span.End()
+
+	if err := VerifyAttestationNoVerifySignature(ctx, beaconState, att); err != nil {
+		return nil, err
+	}
+
+	currEpoch := helpers.CurrentEpoch(beaconState)
+	data := att.Data
+	s := att.Data.Slot
+	proposerIndex, err := helpers.BeaconProposerIndex(beaconState)
+	if err != nil {
+		return nil, err
+	}
+	pendingAtt := &pb.PendingAttestation{
+		Data:            data,
+		AggregationBits: att.AggregationBits,
+		InclusionDelay:  beaconState.Slot() - s,
+		ProposerIndex:   proposerIndex,
+	}
+
+	if data.Target.Epoch == currEpoch {
+		if err := beaconState.AppendCurrentEpochAttestations(pendingAtt); err != nil {
+			return nil, err
+		}
+	} else {
+		if err := beaconState.AppendPreviousEpochAttestations(pendingAtt); err != nil {
+			return nil, err
+		}
+	}
+
+	return beaconState, nil
+}
+
+// VerifyAttestationSignature converts and attestation into an indexed attestation and verifies
+// the signature in that attestation.
+func VerifyAttestationSignature(ctx context.Context, beaconState iface.ReadOnlyBeaconState, att *ethpb.Attestation) error {
+	if err := helpers.ValidateNilAttestation(att); err != nil {
+		return err
+	}
+	committee, err := helpers.BeaconCommitteeFromState(beaconState, att.Data.Slot, att.Data.CommitteeIndex)
+	if err != nil {
+		return err
+	}
+	indexedAtt, err := attestationutil.ConvertToIndexed(ctx, att, committee)
+	if err != nil {
+		return err
+	}
+	return VerifyIndexedAttestation(ctx, beaconState, indexedAtt)
+}
+
+// VerifyIndexedAttestation determines the validity of an indexed attestation.
+//
+// Spec pseudocode definition:
+//  def is_valid_indexed_attestation(state: BeaconState, indexed_attestation: IndexedAttestation) -> bool:
+//    """
+//    Check if ``indexed_attestation`` is not empty, has sorted and unique indices and has a valid aggregate signature.
+//    """
+//    # Verify indices are sorted and unique
+//    indices = indexed_attestation.attesting_indices
+//    if len(indices) == 0 or not indices == sorted(set(indices)):
+//        return False
+//    # Verify aggregate signature
+//    pubkeys = [state.validators[i].pubkey for i in indices]
+//    domain = get_domain(state, DOMAIN_BEACON_ATTESTER, indexed_attestation.data.target.epoch)
+//    signing_root = compute_signing_root(indexed_attestation.data, domain)
+//    return bls.FastAggregateVerify(pubkeys, signing_root, indexed_attestation.signature)
+func VerifyIndexedAttestation(ctx context.Context, beaconState iface.ReadOnlyBeaconState, indexedAtt *ethpb.IndexedAttestation) error {
+	ctx, span := trace.StartSpan(ctx, "core.VerifyIndexedAttestation")
+	defer span.End()
+
+	if err := attestationutil.IsValidAttestationIndices(ctx, indexedAtt); err != nil {
+		return err
+	}
+	domain, err := helpers.Domain(
+		beaconState.Fork(),
+		indexedAtt.Data.Target.Epoch,
+		params.BeaconConfig().DomainBeaconAttester,
+		beaconState.GenesisValidatorRoot(),
+	)
+	if err != nil {
+		return err
+	}
+	indices := indexedAtt.AttestingIndices
+	var pubkeys []bls.PublicKey
+	for i := 0; i < len(indices); i++ {
+		pubkeyAtIdx := beaconState.PubkeyAtIndex(types.ValidatorIndex(indices[i]))
+		pk, err := bls.PublicKeyFromBytes(pubkeyAtIdx[:])
+		if err != nil {
+			return errors.Wrap(err, "could not deserialize validator public key")
+		}
+		pubkeys = append(pubkeys, pk)
+	}
+	return attestationutil.VerifyIndexedAttestationSig(ctx, indexedAtt, pubkeys, domain)
+}
--- a/beacon-chain/core/blocks/attestation_regression_test.go
+++ b/beacon-chain/core/blocks/attestation_regression_test.go
@@ -0,0 +1,80 @@
+package blocks_test
+
+import (
+	"context"
+	"io/ioutil"
+	"testing"
+
+	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
+	"github.com/prysmaticlabs/go-bitfield"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateV0"
+	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+)
+
+// Beaconfuzz discovered an off by one issue where an attestation could be produced which would pass
+// validation when att.Data.CommitteeIndex is 1 and the committee count per slot is also 1. The only
+// valid att.Data.Committee index would be 0, so this is an off by one error.
+// See: https://github.com/sigp/beacon-fuzz/issues/78
+func TestProcessAttestationNoVerifySignature_BeaconFuzzIssue78(t *testing.T) {
+	attData, err := ioutil.ReadFile("testdata/beaconfuzz_78_attestation.ssz")
+	if err != nil {
+		t.Fatal(err)
+	}
+	att := &ethpb.Attestation{}
+	if err := att.UnmarshalSSZ(attData); err != nil {
+		t.Fatal(err)
+	}
+	stateData, err := ioutil.ReadFile("testdata/beaconfuzz_78_beacon.ssz")
+	if err != nil {
+		t.Fatal(err)
+	}
+	spb := &pb.BeaconState{}
+	if err := spb.UnmarshalSSZ(stateData); err != nil {
+		t.Fatal(err)
+	}
+	st, err := stateV0.InitializeFromProtoUnsafe(spb)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	ctx := context.Background()
+	_, err = blocks.ProcessAttestationNoVerifySignature(ctx, st, att)
+	require.ErrorContains(t, "committee index 1 >= committee count 1", err)
+}
+
+// Regression introduced in https://github.com/prysmaticlabs/prysm/pull/8566.
+func TestVerifyAttestationNoVerifySignature_IncorrectSourceEpoch(t *testing.T) {
+	// Attestation with an empty signature
+
+	beaconState, _ := testutil.DeterministicGenesisState(t, 100)
+
+	aggBits := bitfield.NewBitlist(3)
+	aggBits.SetBitAt(1, true)
+	var mockRoot [32]byte
+	copy(mockRoot[:], "hello-world")
+	att := &ethpb.Attestation{
+		Data: &ethpb.AttestationData{
+			Source: &ethpb.Checkpoint{Epoch: 99, Root: mockRoot[:]},
+			Target: &ethpb.Checkpoint{Epoch: 0, Root: make([]byte, 32)},
+		},
+		AggregationBits: aggBits,
+	}
+
+	zeroSig := [96]byte{}
+	att.Signature = zeroSig[:]
+
+	err := beaconState.SetSlot(beaconState.Slot() + params.BeaconConfig().MinAttestationInclusionDelay)
+	require.NoError(t, err)
+	ckp := beaconState.CurrentJustifiedCheckpoint()
+	copy(ckp.Root, "hello-world")
+	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(ckp))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
+
+	err = blocks.VerifyAttestationNoVerifySignature(context.TODO(), beaconState, att)
+	assert.NotEqual(t, nil, err)
+}
--- a/beacon-chain/core/blocks/attestation_test.go
+++ b/beacon-chain/core/blocks/attestation_test.go
@@ -0,0 +1,785 @@
+package blocks_test
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
+	"github.com/prysmaticlabs/go-bitfield"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateV0"
+	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
+	"github.com/prysmaticlabs/prysm/shared/aggregation"
+	attaggregation "github.com/prysmaticlabs/prysm/shared/aggregation/attestations"
+	"github.com/prysmaticlabs/prysm/shared/attestationutil"
+	"github.com/prysmaticlabs/prysm/shared/bls"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+)
+
+func TestProcessAttestations_InclusionDelayFailure(t *testing.T) {
+	attestations := []*ethpb.Attestation{
+		testutil.HydrateAttestation(&ethpb.Attestation{
+			Data: &ethpb.AttestationData{
+				Target: &ethpb.Checkpoint{Epoch: 0, Root: make([]byte, 32)},
+				Slot:   5,
+			},
+		}),
+	}
+	b := testutil.NewBeaconBlock()
+	b.Block = &ethpb.BeaconBlock{
+		Body: &ethpb.BeaconBlockBody{
+			Attestations: attestations,
+		},
+	}
+	beaconState, _ := testutil.DeterministicGenesisState(t, 100)
+
+	want := fmt.Sprintf(
+		"attestation slot %d + inclusion delay %d > state slot %d",
+		attestations[0].Data.Slot,
+		params.BeaconConfig().MinAttestationInclusionDelay,
+		beaconState.Slot(),
+	)
+	_, err := blocks.ProcessAttestations(context.Background(), beaconState, b)
+	assert.ErrorContains(t, want, err)
+}
+
+func TestProcessAttestations_NeitherCurrentNorPrevEpoch(t *testing.T) {
+	att := testutil.HydrateAttestation(&ethpb.Attestation{
+		Data: &ethpb.AttestationData{
+			Source: &ethpb.Checkpoint{Epoch: 0, Root: []byte("hello-world")},
+			Target: &ethpb.Checkpoint{Epoch: 0}}})
+
+	b := testutil.NewBeaconBlock()
+	b.Block = &ethpb.BeaconBlock{
+		Body: &ethpb.BeaconBlockBody{
+			Attestations: []*ethpb.Attestation{att},
+		},
+	}
+	beaconState, _ := testutil.DeterministicGenesisState(t, 100)
+	err := beaconState.SetSlot(beaconState.Slot() + params.BeaconConfig().SlotsPerEpoch*4 + params.BeaconConfig().MinAttestationInclusionDelay)
+	require.NoError(t, err)
+	pfc := beaconState.PreviousJustifiedCheckpoint()
+	pfc.Root = []byte("hello-world")
+	require.NoError(t, beaconState.SetPreviousJustifiedCheckpoint(pfc))
+	require.NoError(t, beaconState.AppendPreviousEpochAttestations(&pb.PendingAttestation{}))
+
+	want := fmt.Sprintf(
+		"expected target epoch (%d) to be the previous epoch (%d) or the current epoch (%d)",
+		att.Data.Target.Epoch,
+		helpers.PrevEpoch(beaconState),
+		helpers.CurrentEpoch(beaconState),
+	)
+	_, err = blocks.ProcessAttestations(context.Background(), beaconState, b)
+	assert.ErrorContains(t, want, err)
+}
+
+func TestProcessAttestations_CurrentEpochFFGDataMismatches(t *testing.T) {
+	attestations := []*ethpb.Attestation{
+		{
+			Data: &ethpb.AttestationData{
+				Target: &ethpb.Checkpoint{Epoch: 0, Root: make([]byte, 32)},
+				Source: &ethpb.Checkpoint{Epoch: 1, Root: make([]byte, 32)},
+			},
+			AggregationBits: bitfield.Bitlist{0x09},
+		},
+	}
+	b := testutil.NewBeaconBlock()
+	b.Block = &ethpb.BeaconBlock{
+		Body: &ethpb.BeaconBlockBody{
+			Attestations: attestations,
+		},
+	}
+	beaconState, _ := testutil.DeterministicGenesisState(t, 100)
+	require.NoError(t, beaconState.SetSlot(beaconState.Slot()+params.BeaconConfig().MinAttestationInclusionDelay))
+	cfc := beaconState.CurrentJustifiedCheckpoint()
+	cfc.Root = []byte("hello-world")
+	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cfc))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
+
+	want := "source check point not equal to current justified checkpoint"
+	_, err := blocks.ProcessAttestations(context.Background(), beaconState, b)
+	assert.ErrorContains(t, want, err)
+	b.Block.Body.Attestations[0].Data.Source.Epoch = helpers.CurrentEpoch(beaconState)
+	b.Block.Body.Attestations[0].Data.Source.Root = []byte{}
+	_, err = blocks.ProcessAttestations(context.Background(), beaconState, b)
+	assert.ErrorContains(t, want, err)
+}
+
+func TestProcessAttestations_PrevEpochFFGDataMismatches(t *testing.T) {
+	beaconState, _ := testutil.DeterministicGenesisState(t, 100)
+
+	aggBits := bitfield.NewBitlist(3)
+	aggBits.SetBitAt(0, true)
+	attestations := []*ethpb.Attestation{
+		{
+			Data: &ethpb.AttestationData{
+				Source: &ethpb.Checkpoint{Epoch: 1, Root: make([]byte, 32)},
+				Target: &ethpb.Checkpoint{Epoch: 1, Root: make([]byte, 32)},
+				Slot:   params.BeaconConfig().SlotsPerEpoch,
+			},
+			AggregationBits: aggBits,
+		},
+	}
+	b := testutil.NewBeaconBlock()
+	b.Block = &ethpb.BeaconBlock{
+		Body: &ethpb.BeaconBlockBody{
+			Attestations: attestations,
+		},
+	}
+
+	err := beaconState.SetSlot(beaconState.Slot() + 2*params.BeaconConfig().SlotsPerEpoch)
+	require.NoError(t, err)
+	pfc := beaconState.PreviousJustifiedCheckpoint()
+	pfc.Root = []byte("hello-world")
+	require.NoError(t, beaconState.SetPreviousJustifiedCheckpoint(pfc))
+	require.NoError(t, beaconState.AppendPreviousEpochAttestations(&pb.PendingAttestation{}))
+
+	want := "source check point not equal to previous justified checkpoint"
+	_, err = blocks.ProcessAttestations(context.Background(), beaconState, b)
+	assert.ErrorContains(t, want, err)
+	b.Block.Body.Attestations[0].Data.Source.Epoch = helpers.PrevEpoch(beaconState)
+	b.Block.Body.Attestations[0].Data.Target.Epoch = helpers.PrevEpoch(beaconState)
+	b.Block.Body.Attestations[0].Data.Source.Root = []byte{}
+	_, err = blocks.ProcessAttestations(context.Background(), beaconState, b)
+	assert.ErrorContains(t, want, err)
+}
+
+func TestProcessAttestations_InvalidAggregationBitsLength(t *testing.T) {
+	beaconState, _ := testutil.DeterministicGenesisState(t, 100)
+
+	aggBits := bitfield.NewBitlist(4)
+	att := &ethpb.Attestation{
+		Data: &ethpb.AttestationData{
+			Source: &ethpb.Checkpoint{Epoch: 0, Root: []byte("hello-world")},
+			Target: &ethpb.Checkpoint{Epoch: 0}},
+		AggregationBits: aggBits,
+	}
+
+	b := testutil.NewBeaconBlock()
+	b.Block = &ethpb.BeaconBlock{
+		Body: &ethpb.BeaconBlockBody{
+			Attestations: []*ethpb.Attestation{att},
+		},
+	}
+
+	err := beaconState.SetSlot(beaconState.Slot() + params.BeaconConfig().MinAttestationInclusionDelay)
+	require.NoError(t, err)
+
+	cfc := beaconState.CurrentJustifiedCheckpoint()
+	cfc.Root = []byte("hello-world")
+	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cfc))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
+
+	expected := "failed to verify aggregation bitfield: wanted participants bitfield length 3, got: 4"
+	_, err = blocks.ProcessAttestations(context.Background(), beaconState, b)
+	assert.ErrorContains(t, expected, err)
+}
+
+func TestProcessAttestations_OK(t *testing.T) {
+	beaconState, privKeys := testutil.DeterministicGenesisState(t, 100)
+
+	aggBits := bitfield.NewBitlist(3)
+	aggBits.SetBitAt(0, true)
+	var mockRoot [32]byte
+	copy(mockRoot[:], "hello-world")
+	att := testutil.HydrateAttestation(&ethpb.Attestation{
+		Data: &ethpb.AttestationData{
+			Source: &ethpb.Checkpoint{Root: mockRoot[:]},
+			Target: &ethpb.Checkpoint{Root: mockRoot[:]},
+		},
+		AggregationBits: aggBits,
+	})
+
+	cfc := beaconState.CurrentJustifiedCheckpoint()
+	cfc.Root = mockRoot[:]
+	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cfc))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
+
+	committee, err := helpers.BeaconCommitteeFromState(beaconState, att.Data.Slot, att.Data.CommitteeIndex)
+	require.NoError(t, err)
+	attestingIndices, err := attestationutil.AttestingIndices(att.AggregationBits, committee)
+	require.NoError(t, err)
+	sigs := make([]bls.Signature, len(attestingIndices))
+	for i, indice := range attestingIndices {
+		sb, err := helpers.ComputeDomainAndSign(beaconState, 0, att.Data, params.BeaconConfig().DomainBeaconAttester, privKeys[indice])
+		require.NoError(t, err)
+		sig, err := bls.SignatureFromBytes(sb)
+		require.NoError(t, err)
+		sigs[i] = sig
+	}
+	att.Signature = bls.AggregateSignatures(sigs).Marshal()
+
+	block := testutil.NewBeaconBlock()
+	block.Block.Body.Attestations = []*ethpb.Attestation{att}
+
+	err = beaconState.SetSlot(beaconState.Slot() + params.BeaconConfig().MinAttestationInclusionDelay)
+	require.NoError(t, err)
+	_, err = blocks.ProcessAttestations(context.Background(), beaconState, block)
+	assert.NoError(t, err)
+}
+
+func TestProcessAggregatedAttestation_OverlappingBits(t *testing.T) {
+	beaconState, privKeys := testutil.DeterministicGenesisState(t, 100)
+	data := testutil.HydrateAttestationData(&ethpb.AttestationData{
+		Source: &ethpb.Checkpoint{Epoch: 0, Root: bytesutil.PadTo([]byte("hello-world"), 32)},
+		Target: &ethpb.Checkpoint{Epoch: 0, Root: bytesutil.PadTo([]byte("hello-world"), 32)},
+	})
+	aggBits1 := bitfield.NewBitlist(3)
+	aggBits1.SetBitAt(0, true)
+	aggBits1.SetBitAt(1, true)
+	att1 := &ethpb.Attestation{
+		Data:            data,
+		AggregationBits: aggBits1,
+	}
+
+	cfc := beaconState.CurrentJustifiedCheckpoint()
+	cfc.Root = bytesutil.PadTo([]byte("hello-world"), 32)
+	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cfc))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
+
+	committee, err := helpers.BeaconCommitteeFromState(beaconState, att1.Data.Slot, att1.Data.CommitteeIndex)
+	require.NoError(t, err)
+	attestingIndices1, err := attestationutil.AttestingIndices(att1.AggregationBits, committee)
+	require.NoError(t, err)
+	sigs := make([]bls.Signature, len(attestingIndices1))
+	for i, indice := range attestingIndices1 {
+		sb, err := helpers.ComputeDomainAndSign(beaconState, 0, att1.Data, params.BeaconConfig().DomainBeaconAttester, privKeys[indice])
+		require.NoError(t, err)
+		sig, err := bls.SignatureFromBytes(sb)
+		require.NoError(t, err)
+		sigs[i] = sig
+	}
+	att1.Signature = bls.AggregateSignatures(sigs).Marshal()
+
+	aggBits2 := bitfield.NewBitlist(3)
+	aggBits2.SetBitAt(1, true)
+	aggBits2.SetBitAt(2, true)
+	att2 := &ethpb.Attestation{
+		Data:            data,
+		AggregationBits: aggBits2,
+	}
+
+	committee, err = helpers.BeaconCommitteeFromState(beaconState, att2.Data.Slot, att2.Data.CommitteeIndex)
+	require.NoError(t, err)
+	attestingIndices2, err := attestationutil.AttestingIndices(att2.AggregationBits, committee)
+	require.NoError(t, err)
+	sigs = make([]bls.Signature, len(attestingIndices2))
+	for i, indice := range attestingIndices2 {
+		sb, err := helpers.ComputeDomainAndSign(beaconState, 0, att2.Data, params.BeaconConfig().DomainBeaconAttester, privKeys[indice])
+		require.NoError(t, err)
+		sig, err := bls.SignatureFromBytes(sb)
+		require.NoError(t, err)
+		sigs[i] = sig
+	}
+	att2.Signature = bls.AggregateSignatures(sigs).Marshal()
+
+	_, err = attaggregation.AggregatePair(att1, att2)
+	assert.ErrorContains(t, aggregation.ErrBitsOverlap.Error(), err)
+}
+
+func TestProcessAggregatedAttestation_NoOverlappingBits(t *testing.T) {
+	beaconState, privKeys := testutil.DeterministicGenesisState(t, 300)
+
+	var mockRoot [32]byte
+	copy(mockRoot[:], "hello-world")
+	data := testutil.HydrateAttestationData(&ethpb.AttestationData{
+		Source: &ethpb.Checkpoint{Epoch: 0, Root: mockRoot[:]},
+		Target: &ethpb.Checkpoint{Epoch: 0, Root: mockRoot[:]},
+	})
+	aggBits1 := bitfield.NewBitlist(9)
+	aggBits1.SetBitAt(0, true)
+	aggBits1.SetBitAt(1, true)
+	att1 := &ethpb.Attestation{
+		Data:            data,
+		AggregationBits: aggBits1,
+		Signature:       make([]byte, 32),
+	}
+
+	cfc := beaconState.CurrentJustifiedCheckpoint()
+	cfc.Root = mockRoot[:]
+	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cfc))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
+
+	committee, err := helpers.BeaconCommitteeFromState(beaconState, att1.Data.Slot, att1.Data.CommitteeIndex)
+	require.NoError(t, err)
+	attestingIndices1, err := attestationutil.AttestingIndices(att1.AggregationBits, committee)
+	require.NoError(t, err)
+	sigs := make([]bls.Signature, len(attestingIndices1))
+	for i, indice := range attestingIndices1 {
+		sb, err := helpers.ComputeDomainAndSign(beaconState, 0, data, params.BeaconConfig().DomainBeaconAttester, privKeys[indice])
+		require.NoError(t, err)
+		sig, err := bls.SignatureFromBytes(sb)
+		require.NoError(t, err)
+		sigs[i] = sig
+	}
+	att1.Signature = bls.AggregateSignatures(sigs).Marshal()
+
+	aggBits2 := bitfield.NewBitlist(9)
+	aggBits2.SetBitAt(2, true)
+	aggBits2.SetBitAt(3, true)
+	att2 := &ethpb.Attestation{
+		Data:            data,
+		AggregationBits: aggBits2,
+		Signature:       make([]byte, 32),
+	}
+
+	committee, err = helpers.BeaconCommitteeFromState(beaconState, att2.Data.Slot, att2.Data.CommitteeIndex)
+	require.NoError(t, err)
+	attestingIndices2, err := attestationutil.AttestingIndices(att2.AggregationBits, committee)
+	require.NoError(t, err)
+	sigs = make([]bls.Signature, len(attestingIndices2))
+	for i, indice := range attestingIndices2 {
+		sb, err := helpers.ComputeDomainAndSign(beaconState, 0, att2.Data, params.BeaconConfig().DomainBeaconAttester, privKeys[indice])
+		require.NoError(t, err)
+		sig, err := bls.SignatureFromBytes(sb)
+		require.NoError(t, err)
+		sigs[i] = sig
+	}
+	att2.Signature = bls.AggregateSignatures(sigs).Marshal()
+
+	aggregatedAtt, err := attaggregation.AggregatePair(att1, att2)
+	require.NoError(t, err)
+	block := testutil.NewBeaconBlock()
+	block.Block.Body.Attestations = []*ethpb.Attestation{aggregatedAtt}
+
+	err = beaconState.SetSlot(beaconState.Slot() + params.BeaconConfig().MinAttestationInclusionDelay)
+	require.NoError(t, err)
+
+	_, err = blocks.ProcessAttestations(context.Background(), beaconState, block)
+	assert.NoError(t, err)
+}
+
+func TestVerifyAttestationNoVerifySignature_IncorrectSlotTargetEpoch(t *testing.T) {
+	beaconState, _ := testutil.DeterministicGenesisState(t, 1)
+
+	att := testutil.HydrateAttestation(&ethpb.Attestation{
+		Data: &ethpb.AttestationData{
+			Slot:   params.BeaconConfig().SlotsPerEpoch,
+			Target: &ethpb.Checkpoint{Root: make([]byte, 32)},
+		},
+	})
+	wanted := "slot 32 does not match target epoch 0"
+	err := blocks.VerifyAttestationNoVerifySignature(context.TODO(), beaconState, att)
+	assert.ErrorContains(t, wanted, err)
+}
+
+func TestProcessAttestationsNoVerify_OK(t *testing.T) {
+	// Attestation with an empty signature
+
+	beaconState, _ := testutil.DeterministicGenesisState(t, 100)
+
+	aggBits := bitfield.NewBitlist(3)
+	aggBits.SetBitAt(1, true)
+	var mockRoot [32]byte
+	copy(mockRoot[:], "hello-world")
+	att := &ethpb.Attestation{
+		Data: &ethpb.AttestationData{
+			Source: &ethpb.Checkpoint{Epoch: 0, Root: mockRoot[:]},
+			Target: &ethpb.Checkpoint{Epoch: 0, Root: make([]byte, 32)},
+		},
+		AggregationBits: aggBits,
+	}
+
+	zeroSig := [96]byte{}
+	att.Signature = zeroSig[:]
+
+	err := beaconState.SetSlot(beaconState.Slot() + params.BeaconConfig().MinAttestationInclusionDelay)
+	require.NoError(t, err)
+	ckp := beaconState.CurrentJustifiedCheckpoint()
+	copy(ckp.Root, "hello-world")
+	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(ckp))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
+
+	_, err = blocks.ProcessAttestationNoVerifySignature(context.TODO(), beaconState, att)
+	assert.NoError(t, err)
+}
+
+func TestVerifyAttestationNoVerifySignature_OK(t *testing.T) {
+	// Attestation with an empty signature
+
+	beaconState, _ := testutil.DeterministicGenesisState(t, 100)
+
+	aggBits := bitfield.NewBitlist(3)
+	aggBits.SetBitAt(1, true)
+	var mockRoot [32]byte
+	copy(mockRoot[:], "hello-world")
+	att := &ethpb.Attestation{
+		Data: &ethpb.AttestationData{
+			Source: &ethpb.Checkpoint{Epoch: 0, Root: mockRoot[:]},
+			Target: &ethpb.Checkpoint{Epoch: 0, Root: make([]byte, 32)},
+		},
+		AggregationBits: aggBits,
+	}
+
+	zeroSig := [96]byte{}
+	att.Signature = zeroSig[:]
+
+	err := beaconState.SetSlot(beaconState.Slot() + params.BeaconConfig().MinAttestationInclusionDelay)
+	require.NoError(t, err)
+	ckp := beaconState.CurrentJustifiedCheckpoint()
+	copy(ckp.Root, "hello-world")
+	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(ckp))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
+
+	err = blocks.VerifyAttestationNoVerifySignature(context.TODO(), beaconState, att)
+	assert.NoError(t, err)
+}
+
+func TestVerifyAttestationNoVerifySignature_BadAttIdx(t *testing.T) {
+	beaconState, _ := testutil.DeterministicGenesisState(t, 100)
+	aggBits := bitfield.NewBitlist(3)
+	aggBits.SetBitAt(1, true)
+	var mockRoot [32]byte
+	copy(mockRoot[:], "hello-world")
+	att := &ethpb.Attestation{
+		Data: &ethpb.AttestationData{
+			CommitteeIndex: 100,
+			Source:         &ethpb.Checkpoint{Epoch: 0, Root: mockRoot[:]},
+			Target:         &ethpb.Checkpoint{Epoch: 0, Root: make([]byte, 32)},
+		},
+		AggregationBits: aggBits,
+	}
+	zeroSig := [96]byte{}
+	att.Signature = zeroSig[:]
+	require.NoError(t, beaconState.SetSlot(beaconState.Slot()+params.BeaconConfig().MinAttestationInclusionDelay))
+	ckp := beaconState.CurrentJustifiedCheckpoint()
+	copy(ckp.Root, "hello-world")
+	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(ckp))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
+	err := blocks.VerifyAttestationNoVerifySignature(context.TODO(), beaconState, att)
+	require.ErrorContains(t, "committee index 100 >= committee count 1", err)
+}
+
+func TestConvertToIndexed_OK(t *testing.T) {
+	helpers.ClearCache()
+	validators := make([]*ethpb.Validator, 2*params.BeaconConfig().SlotsPerEpoch)
+	for i := 0; i < len(validators); i++ {
+		validators[i] = &ethpb.Validator{
+			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
+		}
+	}
+
+	state, err := stateV0.InitializeFromProto(&pb.BeaconState{
+		Slot:        5,
+		Validators:  validators,
+		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
+	})
+	require.NoError(t, err)
+	tests := []struct {
+		aggregationBitfield    bitfield.Bitlist
+		wantedAttestingIndices []uint64
+	}{
+		{
+			aggregationBitfield:    bitfield.Bitlist{0x07},
+			wantedAttestingIndices: []uint64{43, 47},
+		},
+		{
+			aggregationBitfield:    bitfield.Bitlist{0x05},
+			wantedAttestingIndices: []uint64{47},
+		},
+		{
+			aggregationBitfield:    bitfield.Bitlist{0x04},
+			wantedAttestingIndices: []uint64{},
+		},
+	}
+
+	var sig [96]byte
+	copy(sig[:], "signed")
+	attestation := testutil.HydrateAttestation(&ethpb.Attestation{
+		Signature: sig[:],
+	})
+	for _, tt := range tests {
+		attestation.AggregationBits = tt.aggregationBitfield
+		wanted := &ethpb.IndexedAttestation{
+			AttestingIndices: tt.wantedAttestingIndices,
+			Data:             attestation.Data,
+			Signature:        attestation.Signature,
+		}
+
+		committee, err := helpers.BeaconCommitteeFromState(state, attestation.Data.Slot, attestation.Data.CommitteeIndex)
+		require.NoError(t, err)
+		ia, err := attestationutil.ConvertToIndexed(context.Background(), attestation, committee)
+		require.NoError(t, err)
+		assert.DeepEqual(t, wanted, ia, "Convert attestation to indexed attestation didn't result as wanted")
+	}
+}
+
+func TestVerifyIndexedAttestation_OK(t *testing.T) {
+	numOfValidators := uint64(params.BeaconConfig().SlotsPerEpoch.Mul(4))
+	validators := make([]*ethpb.Validator, numOfValidators)
+	_, keys, err := testutil.DeterministicDepositsAndKeys(numOfValidators)
+	require.NoError(t, err)
+	for i := 0; i < len(validators); i++ {
+		validators[i] = &ethpb.Validator{
+			ExitEpoch:             params.BeaconConfig().FarFutureEpoch,
+			PublicKey:             keys[i].PublicKey().Marshal(),
+			WithdrawalCredentials: make([]byte, 32),
+		}
+	}
+
+	state, err := stateV0.InitializeFromProto(&pb.BeaconState{
+		Slot:       5,
+		Validators: validators,
+		Fork: &pb.Fork{
+			Epoch:           0,
+			CurrentVersion:  params.BeaconConfig().GenesisForkVersion,
+			PreviousVersion: params.BeaconConfig().GenesisForkVersion,
+		},
+		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
+	})
+	require.NoError(t, err)
+	tests := []struct {
+		attestation *ethpb.IndexedAttestation
+	}{
+		{attestation: &ethpb.IndexedAttestation{
+			Data: testutil.HydrateAttestationData(&ethpb.AttestationData{
+				Target: &ethpb.Checkpoint{
+					Epoch: 2,
+				},
+				Source: &ethpb.Checkpoint{},
+			}),
+			AttestingIndices: []uint64{1},
+			Signature:        make([]byte, 96),
+		}},
+		{attestation: &ethpb.IndexedAttestation{
+			Data: testutil.HydrateAttestationData(&ethpb.AttestationData{
+				Target: &ethpb.Checkpoint{
+					Epoch: 1,
+				},
+			}),
+			AttestingIndices: []uint64{47, 99, 101},
+			Signature:        make([]byte, 96),
+		}},
+		{attestation: &ethpb.IndexedAttestation{
+			Data: testutil.HydrateAttestationData(&ethpb.AttestationData{
+				Target: &ethpb.Checkpoint{
+					Epoch: 4,
+				},
+			}),
+			AttestingIndices: []uint64{21, 72},
+			Signature:        make([]byte, 96),
+		}},
+		{attestation: &ethpb.IndexedAttestation{
+			Data: testutil.HydrateAttestationData(&ethpb.AttestationData{
+				Target: &ethpb.Checkpoint{
+					Epoch: 7,
+				},
+			}),
+			AttestingIndices: []uint64{100, 121, 122},
+			Signature:        make([]byte, 96),
+		}},
+	}
+
+	for _, tt := range tests {
+		var sig []bls.Signature
+		for _, idx := range tt.attestation.AttestingIndices {
+			sb, err := helpers.ComputeDomainAndSign(state, tt.attestation.Data.Target.Epoch, tt.attestation.Data, params.BeaconConfig().DomainBeaconAttester, keys[idx])
+			require.NoError(t, err)
+			validatorSig, err := bls.SignatureFromBytes(sb)
+			require.NoError(t, err)
+			sig = append(sig, validatorSig)
+		}
+		aggSig := bls.AggregateSignatures(sig)
+		marshalledSig := aggSig.Marshal()
+
+		tt.attestation.Signature = marshalledSig
+
+		err = blocks.VerifyIndexedAttestation(context.Background(), state, tt.attestation)
+		assert.NoError(t, err, "Failed to verify indexed attestation")
+	}
+}
+
+func TestValidateIndexedAttestation_AboveMaxLength(t *testing.T) {
+	indexedAtt1 := &ethpb.IndexedAttestation{
+		AttestingIndices: make([]uint64, params.BeaconConfig().MaxValidatorsPerCommittee+5),
+	}
+
+	for i := uint64(0); i < params.BeaconConfig().MaxValidatorsPerCommittee+5; i++ {
+		indexedAtt1.AttestingIndices[i] = i
+		indexedAtt1.Data = &ethpb.AttestationData{
+			Target: &ethpb.Checkpoint{
+				Epoch: types.Epoch(i),
+			},
+		}
+	}
+
+	want := "validator indices count exceeds MAX_VALIDATORS_PER_COMMITTEE"
+	err := blocks.VerifyIndexedAttestation(context.Background(), &stateV0.BeaconState{}, indexedAtt1)
+	assert.ErrorContains(t, want, err)
+}
+
+func TestValidateIndexedAttestation_BadAttestationsSignatureSet(t *testing.T) {
+	beaconState, keys := testutil.DeterministicGenesisState(t, 128)
+
+	sig := keys[0].Sign([]byte{'t', 'e', 's', 't'})
+	list := bitfield.Bitlist{0b11111}
+	var atts []*ethpb.Attestation
+	for i := uint64(0); i < 1000; i++ {
+		atts = append(atts, &ethpb.Attestation{
+			Data: &ethpb.AttestationData{
+				CommitteeIndex: 1,
+				Slot:           1,
+			},
+			Signature:       sig.Marshal(),
+			AggregationBits: list,
+		})
+	}
+
+	want := "nil or missing indexed attestation data"
+	_, err := blocks.AttestationSignatureSet(context.Background(), beaconState, atts)
+	assert.ErrorContains(t, want, err)
+
+	atts = []*ethpb.Attestation{}
+	list = bitfield.Bitlist{0b10000}
+	for i := uint64(0); i < 1000; i++ {
+		atts = append(atts, &ethpb.Attestation{
+			Data: &ethpb.AttestationData{
+				CommitteeIndex: 1,
+				Slot:           1,
+				Target: &ethpb.Checkpoint{
+					Root: []byte{},
+				},
+			},
+			Signature:       sig.Marshal(),
+			AggregationBits: list,
+		})
+	}
+
+	want = "expected non-empty attesting indices"
+	_, err = blocks.AttestationSignatureSet(context.Background(), beaconState, atts)
+	assert.ErrorContains(t, want, err)
+}
+
+func TestVerifyAttestations_HandlesPlannedFork(t *testing.T) {
+	// In this test, att1 is from the prior fork and att2 is from the new fork.
+	numOfValidators := uint64(params.BeaconConfig().SlotsPerEpoch.Mul(4))
+	validators := make([]*ethpb.Validator, numOfValidators)
+	_, keys, err := testutil.DeterministicDepositsAndKeys(numOfValidators)
+	require.NoError(t, err)
+	for i := 0; i < len(validators); i++ {
+		validators[i] = &ethpb.Validator{
+			ExitEpoch:             params.BeaconConfig().FarFutureEpoch,
+			PublicKey:             keys[i].PublicKey().Marshal(),
+			WithdrawalCredentials: make([]byte, 32),
+		}
+	}
+
+	st, err := testutil.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, st.SetSlot(35))
+	require.NoError(t, st.SetValidators(validators))
+	require.NoError(t, st.SetFork(&pb.Fork{
+		Epoch:           1,
+		CurrentVersion:  []byte{0, 1, 2, 3},
+		PreviousVersion: params.BeaconConfig().GenesisForkVersion,
+	}))
+
+	comm1, err := helpers.BeaconCommitteeFromState(st, 1 /*slot*/, 0 /*committeeIndex*/)
+	require.NoError(t, err)
+	att1 := testutil.HydrateAttestation(&ethpb.Attestation{
+		AggregationBits: bitfield.NewBitlist(uint64(len(comm1))),
+		Data: &ethpb.AttestationData{
+			Slot: 1,
+		},
+	})
+	prevDomain, err := helpers.Domain(st.Fork(), st.Fork().Epoch-1, params.BeaconConfig().DomainBeaconAttester, st.GenesisValidatorRoot())
+	require.NoError(t, err)
+	root, err := helpers.ComputeSigningRoot(att1.Data, prevDomain)
+	require.NoError(t, err)
+	var sigs []bls.Signature
+	for i, u := range comm1 {
+		att1.AggregationBits.SetBitAt(uint64(i), true)
+		sigs = append(sigs, keys[u].Sign(root[:]))
+	}
+	att1.Signature = bls.AggregateSignatures(sigs).Marshal()
+
+	comm2, err := helpers.BeaconCommitteeFromState(st, 1*params.BeaconConfig().SlotsPerEpoch+1 /*slot*/, 1 /*committeeIndex*/)
+	require.NoError(t, err)
+	att2 := testutil.HydrateAttestation(&ethpb.Attestation{
+		AggregationBits: bitfield.NewBitlist(uint64(len(comm2))),
+		Data: &ethpb.AttestationData{
+			Slot:           1*params.BeaconConfig().SlotsPerEpoch + 1,
+			CommitteeIndex: 1,
+		},
+	})
+	currDomain, err := helpers.Domain(st.Fork(), st.Fork().Epoch, params.BeaconConfig().DomainBeaconAttester, st.GenesisValidatorRoot())
+	require.NoError(t, err)
+	root, err = helpers.ComputeSigningRoot(att2.Data, currDomain)
+	require.NoError(t, err)
+	sigs = nil
+	for i, u := range comm2 {
+		att2.AggregationBits.SetBitAt(uint64(i), true)
+		sigs = append(sigs, keys[u].Sign(root[:]))
+	}
+	att2.Signature = bls.AggregateSignatures(sigs).Marshal()
+}
+
+func TestRetrieveAttestationSignatureSet_VerifiesMultipleAttestations(t *testing.T) {
+	ctx := context.Background()
+	numOfValidators := uint64(params.BeaconConfig().SlotsPerEpoch.Mul(4))
+	validators := make([]*ethpb.Validator, numOfValidators)
+	_, keys, err := testutil.DeterministicDepositsAndKeys(numOfValidators)
+	require.NoError(t, err)
+	for i := 0; i < len(validators); i++ {
+		validators[i] = &ethpb.Validator{
+			ExitEpoch:             params.BeaconConfig().FarFutureEpoch,
+			PublicKey:             keys[i].PublicKey().Marshal(),
+			WithdrawalCredentials: make([]byte, 32),
+		}
+	}
+
+	st, err := testutil.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, st.SetSlot(5))
+	require.NoError(t, st.SetValidators(validators))
+
+	comm1, err := helpers.BeaconCommitteeFromState(st, 1 /*slot*/, 0 /*committeeIndex*/)
+	require.NoError(t, err)
+	att1 := testutil.HydrateAttestation(&ethpb.Attestation{
+		AggregationBits: bitfield.NewBitlist(uint64(len(comm1))),
+		Data: &ethpb.AttestationData{
+			Slot: 1,
+		},
+	})
+	domain, err := helpers.Domain(st.Fork(), st.Fork().Epoch, params.BeaconConfig().DomainBeaconAttester, st.GenesisValidatorRoot())
+	require.NoError(t, err)
+	root, err := helpers.ComputeSigningRoot(att1.Data, domain)
+	require.NoError(t, err)
+	var sigs []bls.Signature
+	for i, u := range comm1 {
+		att1.AggregationBits.SetBitAt(uint64(i), true)
+		sigs = append(sigs, keys[u].Sign(root[:]))
+	}
+	att1.Signature = bls.AggregateSignatures(sigs).Marshal()
+
+	comm2, err := helpers.BeaconCommitteeFromState(st, 1 /*slot*/, 1 /*committeeIndex*/)
+	require.NoError(t, err)
+	att2 := testutil.HydrateAttestation(&ethpb.Attestation{
+		AggregationBits: bitfield.NewBitlist(uint64(len(comm2))),
+		Data: &ethpb.AttestationData{
+			Slot:           1,
+			CommitteeIndex: 1,
+		},
+	})
+	root, err = helpers.ComputeSigningRoot(att2.Data, domain)
+	require.NoError(t, err)
+	sigs = nil
+	for i, u := range comm2 {
+		att2.AggregationBits.SetBitAt(uint64(i), true)
+		sigs = append(sigs, keys[u].Sign(root[:]))
+	}
+	att2.Signature = bls.AggregateSignatures(sigs).Marshal()
+
+	set, err := blocks.AttestationSignatureSet(ctx, st, []*ethpb.Attestation{att1, att2})
+	require.NoError(t, err)
+	verified, err := set.Verify()
+	require.NoError(t, err)
+	assert.Equal(t, true, verified, "Multiple signatures were unable to be verified.")
+}
--- a/beacon-chain/core/blocks/attester_slashing.go
+++ b/beacon-chain/core/blocks/attester_slashing.go
@@ -0,0 +1,134 @@
+package blocks
+
+import (
+	"context"
+	"sort"
+
+	"github.com/pkg/errors"
+	types "github.com/prysmaticlabs/eth2-types"
+	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
+	"github.com/prysmaticlabs/prysm/shared/attestationutil"
+	"github.com/prysmaticlabs/prysm/shared/slashutil"
+	"github.com/prysmaticlabs/prysm/shared/sliceutil"
+)
+
+// ProcessAttesterSlashings is one of the operations performed
+// on each processed beacon block to slash attesters based on
+// Casper FFG slashing conditions if any slashable events occurred.
+//
+// Spec pseudocode definition:
+//   def process_attester_slashing(state: BeaconState, attester_slashing: AttesterSlashing) -> None:
+//    attestation_1 = attester_slashing.attestation_1
+//    attestation_2 = attester_slashing.attestation_2
+//    assert is_slashable_attestation_data(attestation_1.data, attestation_2.data)
+//    assert is_valid_indexed_attestation(state, attestation_1)
+//    assert is_valid_indexed_attestation(state, attestation_2)
+//
+//    slashed_any = False
+//    indices = set(attestation_1.attesting_indices).intersection(attestation_2.attesting_indices)
+//    for index in sorted(indices):
+//        if is_slashable_validator(state.validators[index], get_current_epoch(state)):
+//            slash_validator(state, index)
+//            slashed_any = True
+//    assert slashed_any
+func ProcessAttesterSlashings(
+	ctx context.Context,
+	beaconState iface.BeaconState,
+	slashings []*ethpb.AttesterSlashing,
+	slashFunc slashValidatorFunc,
+) (iface.BeaconState, error) {
+	for idx, slashing := range slashings {
+		if err := VerifyAttesterSlashing(ctx, beaconState, slashing); err != nil {
+			return nil, errors.Wrapf(err, "could not verify attester slashing %d", idx)
+		}
+		slashableIndices := slashableAttesterIndices(slashing)
+		sort.SliceStable(slashableIndices, func(i, j int) bool {
+			return slashableIndices[i] < slashableIndices[j]
+		})
+		currentEpoch := helpers.SlotToEpoch(beaconState.Slot())
+		var err error
+		var slashedAny bool
+		var val iface.ReadOnlyValidator
+		for _, validatorIndex := range slashableIndices {
+			val, err = beaconState.ValidatorAtIndexReadOnly(types.ValidatorIndex(validatorIndex))
+			if err != nil {
+				return nil, err
+			}
+			if helpers.IsSlashableValidator(val.ActivationEpoch(), val.WithdrawableEpoch(), val.Slashed(), currentEpoch) {
+				beaconState, err = slashFunc(beaconState, types.ValidatorIndex(validatorIndex))
+				if err != nil {
+					return nil, errors.Wrapf(err, "could not slash validator index %d",
+						validatorIndex)
+				}
+				slashedAny = true
+			}
+		}
+		if !slashedAny {
+			return nil, errors.New("unable to slash any validator despite confirmed attester slashing")
+		}
+	}
+	return beaconState, nil
+}
+
+// VerifyAttesterSlashing validates the attestation data in both attestations in the slashing object.
+func VerifyAttesterSlashing(ctx context.Context, beaconState iface.ReadOnlyBeaconState, slashing *ethpb.AttesterSlashing) error {
+	if slashing == nil {
+		return errors.New("nil slashing")
+	}
+	if slashing.Attestation_1 == nil || slashing.Attestation_2 == nil {
+		return errors.New("nil attestation")
+	}
+	if slashing.Attestation_1.Data == nil || slashing.Attestation_2.Data == nil {
+		return errors.New("nil attestation data")
+	}
+	att1 := slashing.Attestation_1
+	att2 := slashing.Attestation_2
+	data1 := att1.Data
+	data2 := att2.Data
+	if !IsSlashableAttestationData(data1, data2) {
+		return errors.New("attestations are not slashable")
+	}
+	if err := VerifyIndexedAttestation(ctx, beaconState, att1); err != nil {
+		return errors.Wrap(err, "could not validate indexed attestation")
+	}
+	if err := VerifyIndexedAttestation(ctx, beaconState, att2); err != nil {
+		return errors.Wrap(err, "could not validate indexed attestation")
+	}
+	return nil
+}
+
+// IsSlashableAttestationData verifies a slashing against the Casper Proof of Stake FFG rules.
+//
+// Spec pseudocode definition:
+//   def is_slashable_attestation_data(data_1: AttestationData, data_2: AttestationData) -> bool:
+//    """
+//    Check if ``data_1`` and ``data_2`` are slashable according to Casper FFG rules.
+//    """
+//    return (
+//        # Double vote
+//        (data_1 != data_2 and data_1.target.epoch == data_2.target.epoch) or
+//        # Surround vote
+//        (data_1.source.epoch < data_2.source.epoch and data_2.target.epoch < data_1.target.epoch)
+//    )
+func IsSlashableAttestationData(data1, data2 *ethpb.AttestationData) bool {
+	if data1 == nil || data2 == nil || data1.Target == nil || data2.Target == nil || data1.Source == nil || data2.Source == nil {
+		return false
+	}
+	isDoubleVote := !attestationutil.AttDataIsEqual(data1, data2) && data1.Target.Epoch == data2.Target.Epoch
+	att1 := &ethpb.IndexedAttestation{Data: data1}
+	att2 := &ethpb.IndexedAttestation{Data: data2}
+	// Check if att1 is surrounding att2.
+	isSurroundVote := slashutil.IsSurround(att1, att2)
+	return isDoubleVote || isSurroundVote
+}
+
+func slashableAttesterIndices(slashing *ethpb.AttesterSlashing) []uint64 {
+	if slashing == nil || slashing.Attestation_1 == nil || slashing.Attestation_2 == nil {
+		return nil
+	}
+	indices1 := slashing.Attestation_1.AttestingIndices
+	indices2 := slashing.Attestation_2.AttestingIndices
+	return sliceutil.IntersectionUint64(indices1, indices2)
+}
--- a/beacon-chain/core/blocks/attester_slashing_test.go
+++ b/beacon-chain/core/blocks/attester_slashing_test.go
@@ -0,0 +1,164 @@
+package blocks_test
+
+import (
+	"context"
+	"testing"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	v "github.com/prysmaticlabs/prysm/beacon-chain/core/validators"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateV0"
+	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
+	"github.com/prysmaticlabs/prysm/shared/bls"
+	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+)
+
+func TestSlashableAttestationData_CanSlash(t *testing.T) {
+	att1 := testutil.HydrateAttestationData(&ethpb.AttestationData{
+		Target: &ethpb.Checkpoint{Epoch: 1, Root: make([]byte, 32)},
+		Source: &ethpb.Checkpoint{Root: bytesutil.PadTo([]byte{'A'}, 32)},
+	})
+	att2 := testutil.HydrateAttestationData(&ethpb.AttestationData{
+		Target: &ethpb.Checkpoint{Epoch: 1, Root: make([]byte, 32)},
+		Source: &ethpb.Checkpoint{Root: bytesutil.PadTo([]byte{'B'}, 32)},
+	})
+	assert.Equal(t, true, blocks.IsSlashableAttestationData(att1, att2), "Atts should have been slashable")
+	att1.Target.Epoch = 4
+	att1.Source.Epoch = 2
+	att2.Source.Epoch = 3
+	assert.Equal(t, true, blocks.IsSlashableAttestationData(att1, att2), "Atts should have been slashable")
+}
+
+func TestProcessAttesterSlashings_DataNotSlashable(t *testing.T) {
+	slashings := []*ethpb.AttesterSlashing{{
+		Attestation_1: testutil.HydrateIndexedAttestation(&ethpb.IndexedAttestation{}),
+		Attestation_2: testutil.HydrateIndexedAttestation(&ethpb.IndexedAttestation{
+			Data: &ethpb.AttestationData{
+				Source: &ethpb.Checkpoint{Epoch: 1},
+				Target: &ethpb.Checkpoint{Epoch: 1}},
+		})}}
+
+	var registry []*ethpb.Validator
+	currentSlot := types.Slot(0)
+
+	beaconState, err := stateV0.InitializeFromProto(&pb.BeaconState{
+		Validators: registry,
+		Slot:       currentSlot,
+	})
+	require.NoError(t, err)
+	b := testutil.NewBeaconBlock()
+	b.Block = &ethpb.BeaconBlock{
+		Body: &ethpb.BeaconBlockBody{
+			AttesterSlashings: slashings,
+		},
+	}
+	_, err = blocks.ProcessAttesterSlashings(context.Background(), beaconState, b.Block.Body.AttesterSlashings, v.SlashValidator)
+	assert.ErrorContains(t, "attestations are not slashable", err)
+}
+
+func TestProcessAttesterSlashings_IndexedAttestationFailedToVerify(t *testing.T) {
+	var registry []*ethpb.Validator
+	currentSlot := types.Slot(0)
+
+	beaconState, err := stateV0.InitializeFromProto(&pb.BeaconState{
+		Validators: registry,
+		Slot:       currentSlot,
+	})
+	require.NoError(t, err)
+
+	slashings := []*ethpb.AttesterSlashing{
+		{
+			Attestation_1: testutil.HydrateIndexedAttestation(&ethpb.IndexedAttestation{
+				Data: &ethpb.AttestationData{
+					Source: &ethpb.Checkpoint{Epoch: 1},
+				},
+				AttestingIndices: make([]uint64, params.BeaconConfig().MaxValidatorsPerCommittee+1),
+			}),
+			Attestation_2: testutil.HydrateIndexedAttestation(&ethpb.IndexedAttestation{
+				AttestingIndices: make([]uint64, params.BeaconConfig().MaxValidatorsPerCommittee+1),
+			}),
+		},
+	}
+
+	b := testutil.NewBeaconBlock()
+	b.Block = &ethpb.BeaconBlock{
+		Body: &ethpb.BeaconBlockBody{
+			AttesterSlashings: slashings,
+		},
+	}
+
+	_, err = blocks.ProcessAttesterSlashings(context.Background(), beaconState, b.Block.Body.AttesterSlashings, v.SlashValidator)
+	assert.ErrorContains(t, "validator indices count exceeds MAX_VALIDATORS_PER_COMMITTEE", err)
+}
+
+func TestProcessAttesterSlashings_AppliesCorrectStatus(t *testing.T) {
+	beaconState, privKeys := testutil.DeterministicGenesisState(t, 100)
+	for _, vv := range beaconState.Validators() {
+		vv.WithdrawableEpoch = types.Epoch(params.BeaconConfig().SlotsPerEpoch)
+	}
+
+	att1 := testutil.HydrateIndexedAttestation(&ethpb.IndexedAttestation{
+		Data: &ethpb.AttestationData{
+			Source: &ethpb.Checkpoint{Epoch: 1},
+		},
+		AttestingIndices: []uint64{0, 1},
+	})
+	domain, err := helpers.Domain(beaconState.Fork(), 0, params.BeaconConfig().DomainBeaconAttester, beaconState.GenesisValidatorRoot())
+	require.NoError(t, err)
+	signingRoot, err := helpers.ComputeSigningRoot(att1.Data, domain)
+	assert.NoError(t, err, "Could not get signing root of beacon block header")
+	sig0 := privKeys[0].Sign(signingRoot[:])
+	sig1 := privKeys[1].Sign(signingRoot[:])
+	aggregateSig := bls.AggregateSignatures([]bls.Signature{sig0, sig1})
+	att1.Signature = aggregateSig.Marshal()
+
+	att2 := testutil.HydrateIndexedAttestation(&ethpb.IndexedAttestation{
+		AttestingIndices: []uint64{0, 1},
+	})
+	signingRoot, err = helpers.ComputeSigningRoot(att2.Data, domain)
+	assert.NoError(t, err, "Could not get signing root of beacon block header")
+	sig0 = privKeys[0].Sign(signingRoot[:])
+	sig1 = privKeys[1].Sign(signingRoot[:])
+	aggregateSig = bls.AggregateSignatures([]bls.Signature{sig0, sig1})
+	att2.Signature = aggregateSig.Marshal()
+
+	slashings := []*ethpb.AttesterSlashing{
+		{
+			Attestation_1: att1,
+			Attestation_2: att2,
+		},
+	}
+
+	currentSlot := 2 * params.BeaconConfig().SlotsPerEpoch
+	require.NoError(t, beaconState.SetSlot(currentSlot))
+
+	b := testutil.NewBeaconBlock()
+	b.Block = &ethpb.BeaconBlock{
+		Body: &ethpb.BeaconBlockBody{
+			AttesterSlashings: slashings,
+		},
+	}
+
+	newState, err := blocks.ProcessAttesterSlashings(context.Background(), beaconState, b.Block.Body.AttesterSlashings, v.SlashValidator)
+	require.NoError(t, err)
+	newRegistry := newState.Validators()
+
+	// Given the intersection of slashable indices is [1], only validator
+	// at index 1 should be slashed and exited. We confirm this below.
+	if newRegistry[1].ExitEpoch != beaconState.Validators()[1].ExitEpoch {
+		t.Errorf(
+			`
+			Expected validator at index 1's exit epoch to match
+			%d, received %d instead
+			`,
+			beaconState.Validators()[1].ExitEpoch,
+			newRegistry[1].ExitEpoch,
+		)
+	}
+}
--- a/beacon-chain/core/blocks/block_operations.go
+++ b/beacon-chain/core/blocks/block_operations.go
--- a/beacon-chain/core/blocks/block_operations_fuzz_test.go
+++ b/beacon-chain/core/blocks/block_operations_fuzz_test.go
@@ -5,55 +5,56 @@ import (
 	"testing"

 	fuzz "github.com/google/gofuzz"
+	types "github.com/prysmaticlabs/eth2-types"
 	eth "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	v "github.com/prysmaticlabs/prysm/beacon-chain/core/validators"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateV0"
 	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
 	"github.com/prysmaticlabs/prysm/shared/params"
-
-	//"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
-	beaconstate "github.com/prysmaticlabs/prysm/beacon-chain/state"
-	ethereum_beacon_p2p_v1 "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 )

 func TestFuzzProcessAttestationNoVerify_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
 	ctx := context.Background()
-	state := &ethereum_beacon_p2p_v1.BeaconState{}
+	state := &pb.BeaconState{}
 	att := &eth.Attestation{}

 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(att)
-		s, err := beaconstate.InitializeFromProtoUnsafe(state)
-		_, err = ProcessAttestationNoVerify(ctx, s, att)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
+		require.NoError(t, err)
+		_, err = ProcessAttestationNoVerifySignature(ctx, s, att)
 		_ = err
 	}
 }

 func TestFuzzProcessBlockHeader_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	state := &ethereum_beacon_p2p_v1.BeaconState{}
+	state := &pb.BeaconState{}
 	block := &eth.SignedBeaconBlock{}

 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(block)

-		s, err := beaconstate.InitializeFromProtoUnsafe(state)
-		_, err = ProcessBlockHeader(s, block)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
+		require.NoError(t, err)
+		_, err = ProcessBlockHeader(context.Background(), s, block)
 		_ = err
 	}
 }

 func TestFuzzverifyDepositDataSigningRoot_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	ba := []byte{}
+	var ba []byte
 	pubkey := [48]byte{}
 	sig := [96]byte{}
 	domain := [4]byte{}
-	p := []byte{}
-	s := []byte{}
-	d := []byte{}
+	var p []byte
+	var s []byte
+	var d []byte
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(&ba)
 		fuzzer.Fuzz(&pubkey)
@@ -63,6 +64,7 @@ func TestFuzzverifyDepositDataSigningRoot_10000(t *testing.T) {
 		fuzzer.Fuzz(&s)
 		fuzzer.Fuzz(&d)
 		err := verifySignature(ba, pubkey[:], sig[:], domain[:])
+		_ = err
 		err = verifySignature(ba, p, s, d)
 		_ = err
 	}
@@ -70,14 +72,14 @@ func TestFuzzverifyDepositDataSigningRoot_10000(t *testing.T) {

 func TestFuzzProcessEth1DataInBlock_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	block := &eth.BeaconBlock{}
-	state := &stateTrie.BeaconState{}
+	e := &eth.Eth1Data{}
+	state := &stateV0.BeaconState{}
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
-		fuzzer.Fuzz(block)
-		s, err := ProcessEth1DataInBlock(state, block)
+		fuzzer.Fuzz(e)
+		s, err := ProcessEth1DataInBlock(context.Background(), state, e)
 		if err != nil && s != nil {
-			t.Fatalf("state should be nil on err. found: %v on error: %v for state: %v and block: %v", s, err, state, block)
+			t.Fatalf("state should be nil on err. found: %v on error: %v for state: %v and eth1data: %v", s, err, state, e)
 		}
 	}
 }
@@ -98,13 +100,14 @@ func TestFuzzareEth1DataEqual_10000(t *testing.T) {
 func TestFuzzEth1DataHasEnoughSupport_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
 	eth1data := &eth.Eth1Data{}
-	stateVotes := []*eth.Eth1Data{}
+	var stateVotes []*eth.Eth1Data
 	for i := 0; i < 100000; i++ {
 		fuzzer.Fuzz(eth1data)
 		fuzzer.Fuzz(&stateVotes)
-		s, err := beaconstate.InitializeFromProto(&ethereum_beacon_p2p_v1.BeaconState{
+		s, err := stateV0.InitializeFromProto(&pb.BeaconState{
 			Eth1DataVotes: stateVotes,
 		})
+		require.NoError(t, err)
 		_, err = Eth1DataHasEnoughSupport(s, eth1data)
 		_ = err
 	}
@@ -113,44 +116,47 @@ func TestFuzzEth1DataHasEnoughSupport_10000(t *testing.T) {

 func TestFuzzProcessBlockHeaderNoVerify_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	state := &ethereum_beacon_p2p_v1.BeaconState{}
+	state := &pb.BeaconState{}
 	block := &eth.BeaconBlock{}

 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(block)
-		s, err := beaconstate.InitializeFromProtoUnsafe(state)
-		_, err = ProcessBlockHeaderNoVerify(s, block)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
+		require.NoError(t, err)
+		_, err = ProcessBlockHeaderNoVerify(s, block.Slot, block.ProposerIndex, block.ParentRoot, []byte{})
 		_ = err
 	}
 }

 func TestFuzzProcessRandao_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	state := &ethereum_beacon_p2p_v1.BeaconState{}
-	blockBody := &eth.BeaconBlockBody{}
+	state := &pb.BeaconState{}
+	b := &eth.SignedBeaconBlock{}

 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
-		fuzzer.Fuzz(blockBody)
-		s, err := beaconstate.InitializeFromProtoUnsafe(state)
-		r, err := ProcessRandao(s, blockBody)
+		fuzzer.Fuzz(b)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
+		require.NoError(t, err)
+		r, err := ProcessRandao(context.Background(), s, b)
 		if err != nil && r != nil {
-			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and block: %v", r, err, state, blockBody)
+			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and block: %v", r, err, state, b)
 		}
 	}
 }

 func TestFuzzProcessRandaoNoVerify_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	state := &ethereum_beacon_p2p_v1.BeaconState{}
+	state := &pb.BeaconState{}
 	blockBody := &eth.BeaconBlockBody{}

 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(blockBody)
-		s, err := beaconstate.InitializeFromProtoUnsafe(state)
-		r, err := ProcessRandaoNoVerify(s, blockBody)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
+		require.NoError(t, err)
+		r, err := ProcessRandaoNoVerify(s, blockBody.RandaoReveal)
 		if err != nil && r != nil {
 			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and block: %v", r, err, state, blockBody)
 		}
@@ -159,28 +165,30 @@ func TestFuzzProcessRandaoNoVerify_10000(t *testing.T) {

 func TestFuzzProcessProposerSlashings_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	state := &ethereum_beacon_p2p_v1.BeaconState{}
-	blockBody := &eth.BeaconBlockBody{}
+	state := &pb.BeaconState{}
+	p := &eth.ProposerSlashing{}
 	ctx := context.Background()
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
-		fuzzer.Fuzz(blockBody)
-		s, err := beaconstate.InitializeFromProtoUnsafe(state)
-		r, err := ProcessProposerSlashings(ctx, s, blockBody)
+		fuzzer.Fuzz(p)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
+		require.NoError(t, err)
+		r, err := ProcessProposerSlashings(ctx, s, []*eth.ProposerSlashing{p}, v.SlashValidator)
 		if err != nil && r != nil {
-			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and block: %v", r, err, state, blockBody)
+			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and slashing: %v", r, err, state, p)
 		}
 	}
 }

 func TestFuzzVerifyProposerSlashing_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	state := &ethereum_beacon_p2p_v1.BeaconState{}
+	state := &pb.BeaconState{}
 	proposerSlashing := &eth.ProposerSlashing{}
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(proposerSlashing)
-		s, err := beaconstate.InitializeFromProtoUnsafe(state)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
+		require.NoError(t, err)
 		err = VerifyProposerSlashing(s, proposerSlashing)
 		_ = err
 	}
@@ -188,29 +196,31 @@ func TestFuzzVerifyProposerSlashing_10000(t *testing.T) {

 func TestFuzzProcessAttesterSlashings_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	state := &ethereum_beacon_p2p_v1.BeaconState{}
-	blockBody := &eth.BeaconBlockBody{}
+	state := &pb.BeaconState{}
+	a := &eth.AttesterSlashing{}
 	ctx := context.Background()
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
-		fuzzer.Fuzz(blockBody)
-		s, err := beaconstate.InitializeFromProtoUnsafe(state)
-		r, err := ProcessAttesterSlashings(ctx, s, blockBody)
+		fuzzer.Fuzz(a)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
+		require.NoError(t, err)
+		r, err := ProcessAttesterSlashings(ctx, s, []*eth.AttesterSlashing{a}, v.SlashValidator)
 		if err != nil && r != nil {
-			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and block: %v", r, err, state, blockBody)
+			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and slashing: %v", r, err, state, a)
 		}
 	}
 }

 func TestFuzzVerifyAttesterSlashing_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	state := &ethereum_beacon_p2p_v1.BeaconState{}
+	state := &pb.BeaconState{}
 	attesterSlashing := &eth.AttesterSlashing{}
 	ctx := context.Background()
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(attesterSlashing)
-		s, err := beaconstate.InitializeFromProtoUnsafe(state)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
+		require.NoError(t, err)
 		err = VerifyAttesterSlashing(ctx, s, attesterSlashing)
 		_ = err
 	}
@@ -240,45 +250,48 @@ func TestFuzzslashableAttesterIndices_10000(t *testing.T) {

 func TestFuzzProcessAttestations_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	state := &ethereum_beacon_p2p_v1.BeaconState{}
-	blockBody := &eth.BeaconBlockBody{}
+	state := &pb.BeaconState{}
+	b := &eth.SignedBeaconBlock{}
 	ctx := context.Background()
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
-		fuzzer.Fuzz(blockBody)
-		s, err := beaconstate.InitializeFromProtoUnsafe(state)
-		r, err := ProcessAttestations(ctx, s, blockBody)
+		fuzzer.Fuzz(b)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
+		require.NoError(t, err)
+		r, err := ProcessAttestations(ctx, s, b)
 		if err != nil && r != nil {
-			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and block: %v", r, err, state, blockBody)
+			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and block: %v", r, err, state, b)
 		}
 	}
 }

 func TestFuzzProcessAttestationsNoVerify_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	state := &ethereum_beacon_p2p_v1.BeaconState{}
-	blockBody := &eth.BeaconBlockBody{}
+	state := &pb.BeaconState{}
+	b := &eth.SignedBeaconBlock{}
 	ctx := context.Background()
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
-		fuzzer.Fuzz(blockBody)
-		s, err := beaconstate.InitializeFromProtoUnsafe(state)
-		r, err := ProcessAttestationsNoVerify(ctx, s, blockBody)
+		fuzzer.Fuzz(b)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
+		require.NoError(t, err)
+		r, err := ProcessAttestationsNoVerifySignature(ctx, s, b)
 		if err != nil && r != nil {
-			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and block: %v", r, err, state, blockBody)
+			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and block: %v", r, err, state, b)
 		}
 	}
 }

 func TestFuzzProcessAttestation_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	state := &ethereum_beacon_p2p_v1.BeaconState{}
+	state := &pb.BeaconState{}
 	attestation := &eth.Attestation{}
 	ctx := context.Background()
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(attestation)
-		s, err := beaconstate.InitializeFromProtoUnsafe(state)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
+		require.NoError(t, err)
 		r, err := ProcessAttestation(ctx, s, attestation)
 		if err != nil && r != nil {
 			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and block: %v", r, err, state, attestation)
@@ -288,13 +301,14 @@ func TestFuzzProcessAttestation_10000(t *testing.T) {

 func TestFuzzVerifyIndexedAttestationn_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	state := &ethereum_beacon_p2p_v1.BeaconState{}
+	state := &pb.BeaconState{}
 	idxAttestation := &eth.IndexedAttestation{}
 	ctx := context.Background()
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(idxAttestation)
-		s, err := beaconstate.InitializeFromProtoUnsafe(state)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
+		require.NoError(t, err)
 		err = VerifyIndexedAttestation(ctx, s, idxAttestation)
 		_ = err
 	}
@@ -302,45 +316,50 @@ func TestFuzzVerifyIndexedAttestationn_10000(t *testing.T) {

 func TestFuzzVerifyAttestation_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	state := &ethereum_beacon_p2p_v1.BeaconState{}
+	state := &pb.BeaconState{}
 	attestation := &eth.Attestation{}
 	ctx := context.Background()
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(attestation)
-		s, err := beaconstate.InitializeFromProtoUnsafe(state)
-		err = VerifyAttestation(ctx, s, attestation)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
+		require.NoError(t, err)
+		err = VerifyAttestationSignature(ctx, s, attestation)
 		_ = err
 	}
 }

 func TestFuzzProcessDeposits_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	state := &ethereum_beacon_p2p_v1.BeaconState{}
-	blockBody := &eth.BeaconBlockBody{}
+	state := &pb.BeaconState{}
+	deposits := make([]*eth.Deposit, 100)
 	ctx := context.Background()
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
-		fuzzer.Fuzz(blockBody)
-		s, err := beaconstate.InitializeFromProtoUnsafe(state)
-		r, err := ProcessDeposits(ctx, s, blockBody)
+		for i := range deposits {
+			fuzzer.Fuzz(deposits[i])
+		}
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
+		require.NoError(t, err)
+		r, err := ProcessDeposits(ctx, s, deposits)
 		if err != nil && r != nil {
-			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and block: %v", r, err, state, blockBody)
+			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and block: %v", r, err, state, deposits)
 		}
 	}
 }

 func TestFuzzProcessPreGenesisDeposit_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	state := &ethereum_beacon_p2p_v1.BeaconState{}
+	state := &pb.BeaconState{}
 	deposit := &eth.Deposit{}
 	ctx := context.Background()

 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(deposit)
-		s, err := beaconstate.InitializeFromProtoUnsafe(state)
-		r, err := ProcessPreGenesisDeposit(ctx, s, deposit)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
+		require.NoError(t, err)
+		r, err := ProcessPreGenesisDeposits(ctx, s, []*eth.Deposit{deposit})
 		if err != nil && r != nil {
 			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and block: %v", r, err, state, deposit)
 		}
@@ -349,14 +368,15 @@ func TestFuzzProcessPreGenesisDeposit_10000(t *testing.T) {

 func TestFuzzProcessDeposit_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	state := &ethereum_beacon_p2p_v1.BeaconState{}
+	state := &pb.BeaconState{}
 	deposit := &eth.Deposit{}

 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(deposit)
-		s, err := beaconstate.InitializeFromProtoUnsafe(state)
-		r, err := ProcessDeposit(s, deposit)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
+		require.NoError(t, err)
+		r, err := ProcessDeposit(s, deposit, true)
 		if err != nil && r != nil {
 			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and block: %v", r, err, state, deposit)
 		}
@@ -365,12 +385,13 @@ func TestFuzzProcessDeposit_10000(t *testing.T) {

 func TestFuzzverifyDeposit_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	state := &ethereum_beacon_p2p_v1.BeaconState{}
+	state := &pb.BeaconState{}
 	deposit := &eth.Deposit{}
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(deposit)
-		s, err := beaconstate.InitializeFromProtoUnsafe(state)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
+		require.NoError(t, err)
 		err = verifyDeposit(s, deposit)
 		_ = err
 	}
@@ -378,31 +399,33 @@ func TestFuzzverifyDeposit_10000(t *testing.T) {

 func TestFuzzProcessVoluntaryExits_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	state := &ethereum_beacon_p2p_v1.BeaconState{}
-	blockBody := &eth.BeaconBlockBody{}
+	state := &pb.BeaconState{}
+	e := &eth.SignedVoluntaryExit{}
 	ctx := context.Background()
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
-		fuzzer.Fuzz(blockBody)
-		s, err := beaconstate.InitializeFromProtoUnsafe(state)
-		r, err := ProcessVoluntaryExits(ctx, s, blockBody)
+		fuzzer.Fuzz(e)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
+		require.NoError(t, err)
+		r, err := ProcessVoluntaryExits(ctx, s, []*eth.SignedVoluntaryExit{e})
 		if err != nil && r != nil {
-			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and block: %v", r, err, state, blockBody)
+			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and exit: %v", r, err, state, e)
 		}
 	}
 }

 func TestFuzzProcessVoluntaryExitsNoVerify_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	state := &ethereum_beacon_p2p_v1.BeaconState{}
-	blockBody := &eth.BeaconBlockBody{}
+	state := &pb.BeaconState{}
+	e := &eth.SignedVoluntaryExit{}
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
-		fuzzer.Fuzz(blockBody)
-		s, err := beaconstate.InitializeFromProtoUnsafe(state)
-		r, err := ProcessVoluntaryExitsNoVerify(s, blockBody)
+		fuzzer.Fuzz(e)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
+		require.NoError(t, err)
+		r, err := ProcessVoluntaryExits(context.Background(), s, []*eth.SignedVoluntaryExit{e})
 		if err != nil && r != nil {
-			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and block: %v", r, err, state, blockBody)
+			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and block: %v", r, err, state, e)
 		}
 	}
 }
@@ -410,16 +433,16 @@ func TestFuzzProcessVoluntaryExitsNoVerify_10000(t *testing.T) {
 func TestFuzzVerifyExit_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
 	ve := &eth.SignedVoluntaryExit{}
-	val := &beaconstate.ReadOnlyValidator{}
+	val := stateV0.ReadOnlyValidator{}
 	fork := &pb.Fork{}
-	var slot uint64
+	var slot types.Slot

 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(ve)
-		fuzzer.Fuzz(val)
+		fuzzer.Fuzz(&val)
 		fuzzer.Fuzz(fork)
 		fuzzer.Fuzz(&slot)
-		err := VerifyExit(val, slot, fork, ve, params.BeaconConfig().ZeroHash[:])
+		err := VerifyExitAndSignature(val, slot, fork, ve, params.BeaconConfig().ZeroHash[:])
 		_ = err
 	}
 }
--- a/beacon-chain/core/blocks/block_operations_test.go
+++ b/beacon-chain/core/blocks/block_operations_test.go
--- a/beacon-chain/core/blocks/block_regression_test.go
+++ b/beacon-chain/core/blocks/block_regression_test.go
@@ -4,19 +4,23 @@ import (
 	"context"
 	"testing"

+	types "github.com/prysmaticlabs/eth2-types"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	v "github.com/prysmaticlabs/prysm/beacon-chain/core/validators"
 	"github.com/prysmaticlabs/prysm/shared/bls"
 	"github.com/prysmaticlabs/prysm/shared/params"
 	"github.com/prysmaticlabs/prysm/shared/testutil"
+	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
+	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 )

 func TestProcessAttesterSlashings_RegressionSlashableIndices(t *testing.T) {
 	testutil.ResetCache()
 	beaconState, privKeys := testutil.DeterministicGenesisState(t, 5500)
 	for _, vv := range beaconState.Validators() {
-		vv.WithdrawableEpoch = 1 * params.BeaconConfig().SlotsPerEpoch
+		vv.WithdrawableEpoch = types.Epoch(params.BeaconConfig().SlotsPerEpoch)
 	}
 	// This set of indices is very similar to the one from our sapphire testnet
 	// when close to 100 validators were incorrectly slashed. The set is from 0 -5500,
@@ -36,47 +40,39 @@ func TestProcessAttesterSlashings_RegressionSlashableIndices(t *testing.T) {

 	root1 := [32]byte{'d', 'o', 'u', 'b', 'l', 'e', '1'}
 	att1 := &ethpb.IndexedAttestation{
-		Data: &ethpb.AttestationData{
-			Source: &ethpb.Checkpoint{Epoch: 0},
-			Target: &ethpb.Checkpoint{Epoch: 0, Root: root1[:]},
-		},
+		Data:             testutil.HydrateAttestationData(&ethpb.AttestationData{Target: &ethpb.Checkpoint{Epoch: 0, Root: root1[:]}}),
 		AttestingIndices: setA,
+		Signature:        make([]byte, 96),
 	}
 	domain, err := helpers.Domain(beaconState.Fork(), 0, params.BeaconConfig().DomainBeaconAttester, beaconState.GenesisValidatorRoot())
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 	signingRoot, err := helpers.ComputeSigningRoot(att1.Data, domain)
-	if err != nil {
-		t.Errorf("Could not get signing root of beacon block header: %v", err)
-	}
-	aggSigs := []bls.Signature{}
+	require.NoError(t, err, "Could not get signing root of beacon block header")
+	var aggSigs []bls.Signature
 	for _, index := range setA {
 		sig := privKeys[index].Sign(signingRoot[:])
 		aggSigs = append(aggSigs, sig)
 	}
 	aggregateSig := bls.AggregateSignatures(aggSigs)
-	att1.Signature = aggregateSig.Marshal()[:]
+	att1.Signature = aggregateSig.Marshal()

 	root2 := [32]byte{'d', 'o', 'u', 'b', 'l', 'e', '2'}
 	att2 := &ethpb.IndexedAttestation{
-		Data: &ethpb.AttestationData{
-			Source: &ethpb.Checkpoint{Epoch: 0},
-			Target: &ethpb.Checkpoint{Epoch: 0, Root: root2[:]},
-		},
+		Data: testutil.HydrateAttestationData(&ethpb.AttestationData{
+			Target: &ethpb.Checkpoint{Root: root2[:]},
+		}),
 		AttestingIndices: setB,
+		Signature:        make([]byte, 96),
 	}
 	signingRoot, err = helpers.ComputeSigningRoot(att2.Data, domain)
-	if err != nil {
-		t.Errorf("Could not get signing root of beacon block header: %v", err)
-	}
+	assert.NoError(t, err, "Could not get signing root of beacon block header")
 	aggSigs = []bls.Signature{}
 	for _, index := range setB {
 		sig := privKeys[index].Sign(signingRoot[:])
 		aggSigs = append(aggSigs, sig)
 	}
 	aggregateSig = bls.AggregateSignatures(aggSigs)
-	att2.Signature = aggregateSig.Marshal()[:]
+	att2.Signature = aggregateSig.Marshal()

 	slashings := []*ethpb.AttesterSlashing{
 		{
@@ -86,20 +82,17 @@ func TestProcessAttesterSlashings_RegressionSlashableIndices(t *testing.T) {
 	}

 	currentSlot := 2 * params.BeaconConfig().SlotsPerEpoch
-	if err := beaconState.SetSlot(currentSlot); err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, beaconState.SetSlot(currentSlot))

-	block := &ethpb.BeaconBlock{
+	b := testutil.NewBeaconBlock()
+	b.Block = &ethpb.BeaconBlock{
 		Body: &ethpb.BeaconBlockBody{
 			AttesterSlashings: slashings,
 		},
 	}

-	newState, err := blocks.ProcessAttesterSlashings(context.Background(), beaconState, block.Body)
-	if err != nil {
-		t.Fatal(err)
-	}
+	newState, err := blocks.ProcessAttesterSlashings(context.Background(), beaconState, b.Block.Body.AttesterSlashings, v.SlashValidator)
+	require.NoError(t, err)
 	newRegistry := newState.Validators()
 	if !newRegistry[expectedSlashedVal].Slashed {
 		t.Errorf("Validator with index %d was not slashed despite performing a double vote", expectedSlashedVal)
--- a/beacon-chain/core/blocks/block_test.go
+++ b/beacon-chain/core/blocks/block_test.go
@@ -1,21 +0,0 @@
-package blocks_test
-
-import (
-	"bytes"
-	"testing"
-
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
-)
-
-func TestGenesisBlock_InitializedCorrectly(t *testing.T) {
-	stateHash := []byte{0}
-	b1 := blocks.NewGenesisBlock(stateHash)
-
-	if b1.Block.ParentRoot == nil {
-		t.Error("genesis block missing ParentHash field")
-	}
-
-	if !bytes.Equal(b1.Block.StateRoot, stateHash) {
-		t.Error("genesis block StateRootHash32 isn't initialized correctly")
-	}
-}
--- a/Show More
+++ b/Show More
@@ -1 +1 @@
 .2.0
 .7.0