Update deps.bzl after updating grpc-gateway dependency (#8933 )

Update grpc-gateway dependency (#8929 )
Fix Panic When Accessing State Frequently (#8928 )
2026-01-10 05:47:59 -05:00 · 2021-05-24 16:18:26 +00:00 · 2021-05-24 09:27:50 -05:00 · 2021-05-24 06:52:33 +00:00 · 2021-05-23 21:55:42 -07:00 · 2021-05-23 09:36:46 +02:00
1021 changed files with 39227 additions and 43413 deletions
--- a/.bazelrc
+++ b/.bazelrc
@@ -39,16 +39,15 @@ build --define kafka_enabled=false
 test --define kafka_enabled=false
 run --define kafka_enabled=false

-# Enable blst by default, we use a config so that our fuzzer stops complaining.
-build --config=blst_enabled
-test --config=blst_enabled
-run --config=blst_enabled
+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_enabled --define blst_enabled=true
-build:blst_enabled --define gotags=blst_enabled
+build:blst_disabled --define blst_disabled=true
+build:blst_disabled --define gotags=blst_disabled

 # Release flags
 build:release --compilation_mode=opt
@@ -84,7 +83,7 @@ build:fuzz --linkopt -Wl,--no-as-needed
 build:fuzz --define=gc_goopts=-d=libfuzzer,checkptr
 build:fuzz --run_under=//tools:fuzz_wrapper
 build:fuzz --compilation_mode=opt
-build:fuzz --define=blst_enabled=false
+build:fuzz --define=blst_disabled=true

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

--- a/.buildkite-bazelrc
+++ b/.buildkite-bazelrc
@@ -2,7 +2,7 @@
 # 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_timeout=3600
+#build:remote-cache --remote_timeout=3600
 #build:remote-cache --spawn_strategy=standalone
 #build:remote-cache --strategy=Javac=standalone
 #build:remote-cache --strategy=Closure=standalone
@@ -11,6 +11,13 @@ build:remote-cache --remote_timeout=3600
 # Prysm specific remote-cache properties.
 #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
--- a/.codecov.yml
+++ b/.codecov.yml
@@ -30,4 +30,4 @@ comment:

 ignore:
  - "**/*.pb.go"
-  - "**/*_mock.go"
+  - "**/testing/**/*"
--- a/.deepsource.toml
+++ b/.deepsource.toml
@@ -1,6 +1,10 @@
 version = 1

-exclude_patterns = ["tools/analyzers/**"]
+exclude_patterns = [
+  "tools/analyzers/**",
+  "validator/keymanager/remote/keymanager_test.go",
+  "validator/web/site_data.go"
+]

 [[analyzers]]
 name = "go"
--- a/.github/workflows/go.yml
+++ b/.github/workflows/go.yml
@@ -44,7 +44,7 @@ jobs:

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

 # Tests run via Bazel for now...
 #      - name: Test
--- a/BUILD.bazel
+++ b/BUILD.bazel
@@ -23,7 +23,16 @@ gazelle(
 # Protobuf compiler (non-gRPC)
 alias(
    name = "proto_compiler",
-    actual = "@io_bazel_rules_go//proto:gogofast_proto",
+    actual = "@io_bazel_rules_go//proto:go_proto",
+    visibility = [
+        "//proto:__subpackages__",
+    ],
+)
+
+# Cast protobuf compiler (non-gRPC)
+alias(
+    name = "cast_proto_compiler",
+    actual = "@com_github_prysmaticlabs_protoc_gen_go_cast//:go_cast",
    visibility = [
        "//proto:__subpackages__",
    ],
@@ -32,21 +41,21 @@ alias(
 # Protobuf compiler (gRPC)
 alias(
    name = "grpc_proto_compiler",
-    actual = "@io_bazel_rules_go//proto:gogofast_grpc",
+    actual = "@io_bazel_rules_go//proto:go_grpc",
    visibility = ["//visibility:public"],
 )

-# Protobuf gRPC compiler without gogoproto. Required for gRPC gateway.
+# Cast protobuf compiler (gRPC)
 alias(
-    name = "grpc_nogogo_proto_compiler",
-    actual = "@io_bazel_rules_go//proto:go_grpc",
+    name = "cast_grpc_proto_compiler",
+    actual = "@com_github_prysmaticlabs_protoc_gen_go_cast//:go_cast_grpc",
    visibility = ["//visibility:public"],
 )

 # Protobuf gRPC gateway compiler
 alias(
    name = "grpc_gateway_proto_compiler",
-    actual = "@com_github_grpc_ecosystem_grpc_gateway//protoc-gen-grpc-gateway:go_gen_grpc_gateway",
+    actual = "@com_github_grpc_ecosystem_grpc_gateway_v2//protoc-gen-grpc-gateway:go_gen_grpc_gateway",
    visibility = ["//visibility:public"],
 )

@@ -111,6 +120,7 @@ nogo(
        "//tools/analyzers/shadowpredecl:go_tool_library",
        "//tools/analyzers/nop:go_tool_library",
        "//tools/analyzers/slicedirect:go_tool_library",
+        "//tools/analyzers/interfacechecker:go_tool_library",
        "//tools/analyzers/ineffassign:go_tool_library",
        "//tools/analyzers/properpermissions:go_tool_library",
    ] + select({
--- a/48
+++ b/48
@@ -15,9 +15,9 @@ http_archive(

 http_archive(
    name = "com_grail_bazel_toolchain",
-    sha256 = "b924b102adc0c3368d38a19bd971cb4fa75362a27bc363d0084b90ca6877d3f0",
-    strip_prefix = "bazel-toolchain-0.5.7",
-    urls = ["https://github.com/grailbio/bazel-toolchain/archive/0.5.7.tar.gz"],
+    sha256 = "040b9d00b8a03e8a28e38159ad0f2d0e0de625d93f453a9f226971a8c47e757b",
+    strip_prefix = "bazel-toolchain-5f82830f9d6a1941c3eb29683c1864ccf2862454",
+    urls = ["https://github.com/grailbio/bazel-toolchain/archive/5f82830f9d6a1941c3eb29683c1864ccf2862454.tar.gz"],
 )

 load("@com_grail_bazel_toolchain//toolchain:deps.bzl", "bazel_toolchain_dependencies")
@@ -60,10 +60,10 @@ bazel_skylib_workspace()

 http_archive(
    name = "bazel_gazelle",
-    sha256 = "222e49f034ca7a1d1231422cdb67066b885819885c356673cb1f72f748a3c9d4",
+    sha256 = "62ca106be173579c0a167deb23358fdfe71ffa1e4cfdddf5582af26520f1c66f",
    urls = [
-        "https://mirror.bazel.build/github.com/bazelbuild/bazel-gazelle/releases/download/v0.22.3/bazel-gazelle-v0.22.3.tar.gz",
-        "https://github.com/bazelbuild/bazel-gazelle/releases/download/v0.22.3/bazel-gazelle-v0.22.3.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 = "1286175a94c0b1335efe1d75d22ea06e89742557d3fac2a0366f242a6eac6f5a",
-    strip_prefix = "rules_docker-ba4310833230294fa69b7d6ea1787ac684631a7d",
-    urls = ["https://github.com/bazelbuild/rules_docker/archive/ba4310833230294fa69b7d6ea1787ac684631a7d.tar.gz"],
+    sha256 = "59d5b42ac315e7eadffa944e86e90c2990110a1c8075f1cd145f487e999d22b3",
+    strip_prefix = "rules_docker-0.17.0",
+    urls = ["https://github.com/bazelbuild/rules_docker/releases/download/v0.17.0/rules_docker-v0.17.0.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 = "52d0a57ea12139d727883c2fef03597970b89f2cc2a05722c42d1d7d41ec065b",
+    sha256 = "7c10271940c6bce577d51a075ae77728964db285dac0a46614a7934dc34303e6",
    urls = [
-        "https://mirror.bazel.build/github.com/bazelbuild/rules_go/releases/download/v0.24.13/rules_go-v0.24.13.tar.gz",
-        "https://github.com/bazelbuild/rules_go/releases/download/v0.24.13/rules_go-v0.24.13.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",
    ],
 )

@@ -156,7 +156,7 @@ load("@io_bazel_rules_go//go:deps.bzl", "go_register_toolchains", "go_rules_depe
 go_rules_dependencies()

 go_register_toolchains(
-    go_version = "1.16",
+    go_version = "1.16.4",
    nogo = "@//:nogo",
 )

@@ -231,14 +231,14 @@ http_archive(
 filegroup(
    name = "test_data",
    srcs = glob([
-        "**/*.ssz",
+        "**/*.ssz_snappy",
        "**/*.yaml",
    ]),
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "ef5396e4b13995da9776eeb5ae346a2de90970c28da3c4f0dcaa4ab9f0ad1f93",
-    url = "https://github.com/ethereum/eth2.0-spec-tests/releases/download/v1.0.0/general.tar.gz",
+    sha256 = "deacc076365c727d653ac064894ecf0d1b0a675d86704dc8de271259f6a7314b",
+    url = "https://github.com/ethereum/eth2.0-spec-tests/releases/download/v1.1.0-alpha.3/general.tar.gz",
 )

 http_archive(
@@ -247,14 +247,14 @@ http_archive(
 filegroup(
    name = "test_data",
    srcs = glob([
-        "**/*.ssz",
+        "**/*.ssz_snappy",
        "**/*.yaml",
    ]),
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "170551b441e7d54b73248372ad9ce8cb6c148810b5f1364637117a63f4f1c085",
-    url = "https://github.com/ethereum/eth2.0-spec-tests/releases/download/v1.0.0/minimal.tar.gz",
+    sha256 = "6e9886af3d2f024e563249d70388129e28e3e92f742f289238ed9b7ec7a7f930",
+    url = "https://github.com/ethereum/eth2.0-spec-tests/releases/download/v1.1.0-alpha.3/minimal.tar.gz",
 )

 http_archive(
@@ -263,14 +263,14 @@ http_archive(
 filegroup(
    name = "test_data",
    srcs = glob([
-        "**/*.ssz",
+        "**/*.ssz_snappy",
        "**/*.yaml",
    ]),
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "b541a9979b4703fa5ee5d2182b0b5313c38efc54ae7eaec2eef793230a52ec83",
-    url = "https://github.com/ethereum/eth2.0-spec-tests/releases/download/v1.0.0/mainnet.tar.gz",
+    sha256 = "a7b3d0ffc02a567250f424d69b2474fdc9477cd56eada60af7474560b46a8527",
+    url = "https://github.com/ethereum/eth2.0-spec-tests/releases/download/v1.1.0-alpha.3/mainnet.tar.gz",
 )

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

 git_repository(
    name = "com_google_protobuf",
-    commit = "fde7cf7358ec7cd69e8db9be4f1fa6a5c431386a",  # v3.13.0
+    commit = "436bd7880e458532901c58f4d9d1ea23fa7edd52",
    remote = "https://github.com/protocolbuffers/protobuf",
-    shallow_since = "1597443653 -0700",
+    shallow_since = "1617835118 -0700",
 )

 load("@com_google_protobuf//:protobuf_deps.bzl", "protobuf_deps")
--- 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/blockchain/BUILD.bazel
+++ b/beacon-chain/blockchain/BUILD.bazel
@@ -27,7 +27,6 @@ go_library(
    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",
@@ -42,8 +41,8 @@ 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",
        "//cmd/beacon-chain/flags:go_default_library",
        "//proto/beacon/p2p/v1:go_default_library",
@@ -84,6 +83,7 @@ go_test(
        "checktags_test.go",
        "head_test.go",
        "info_test.go",
+        "init_test.go",
        "metrics_test.go",
        "process_attestation_test.go",
        "process_block_test.go",
@@ -116,11 +116,11 @@ go_test(
        "@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_sirupsen_logrus//:go_default_library",
        "@com_github_sirupsen_logrus//hooks/test:go_default_library",
        "@in_gopkg_d4l3k_messagediff_v1//:go_default_library",
+        "@org_golang_google_protobuf//proto:go_default_library",
        "@org_golang_x_net//context:go_default_library",
    ],
 )
@@ -130,6 +130,7 @@ go_test(
    srcs = [
        "chain_info_norace_test.go",
        "checktags_test.go",
+        "init_test.go",
        "receive_block_test.go",
        "service_norace_test.go",
    ],
@@ -164,10 +165,10 @@ go_test(
        "@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_sirupsen_logrus//:go_default_library",
        "@com_github_sirupsen_logrus//hooks/test:go_default_library",
+        "@org_golang_google_protobuf//proto:go_default_library",
        "@org_golang_x_net//context:go_default_library",
    ],
 )
--- a/beacon-chain/blockchain/chain_info.go
+++ b/beacon-chain/blockchain/chain_info.go
@@ -8,7 +8,8 @@ import (
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
-	"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/params"
@@ -41,12 +42,13 @@ type HeadFetcher interface {
 	HeadSlot() types.Slot
 	HeadRoot(ctx context.Context) ([]byte, error)
 	HeadBlock(ctx context.Context) (*ethpb.SignedBeaconBlock, error)
-	HeadState(ctx context.Context) (*state.BeaconState, 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.
@@ -74,7 +76,7 @@ func (s *Service) FinalizedCheckpt() *ethpb.Checkpoint {
 		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.
@@ -83,7 +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.
@@ -92,7 +94,7 @@ 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.
@@ -117,7 +119,7 @@ func (s *Service) HeadRoot(ctx context.Context) ([]byte, error) {
 		return r[:], nil
 	}

-	b, err := s.beaconDB.HeadBlock(ctx)
+	b, err := s.cfg.BeaconDB.HeadBlock(ctx)
 	if err != nil {
 		return nil, err
 	}
@@ -144,13 +146,13 @@ func (s *Service) HeadBlock(ctx context.Context) (*ethpb.SignedBeaconBlock, erro
 		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) {
+func (s *Service) HeadState(ctx context.Context) (iface.BeaconState, error) {
 	ctx, span := trace.StartSpan(ctx, "blockChain.HeadState")
 	defer span.End()
 	s.headLock.RLock()
@@ -163,7 +165,7 @@ func (s *Service) HeadState(ctx context.Context) (*state.BeaconState, error) {
 		return s.headState(ctx), nil
 	}

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

 // HeadValidatorsIndices returns a list of active validator indices from the head view of a given epoch.
@@ -214,7 +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.
@@ -251,10 +253,32 @@ func (s *Service) CurrentFork() *pb.Fork {
 // 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, check fork choice store to see if the block is canonical
-	return s.forkChoiceStore.IsCanonical(blockRoot), nil
+	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
@@ -13,7 +13,7 @@ import (
 func TestHeadSlot_DataRace(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
 	s := &Service{
-		beaconDB: beaconDB,
+		cfg: &Config{BeaconDB: beaconDB},
 	}
 	go func() {
 		require.NoError(t, s.saveHead(context.Background(), [32]byte{}))
@@ -24,9 +24,8 @@ func TestHeadSlot_DataRace(t *testing.T) {
 func TestHeadRoot_DataRace(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
 	s := &Service{
-		beaconDB: beaconDB,
-		head:     &head{root: [32]byte{'A'}},
-		stateGen: stategen.New(beaconDB),
+		cfg:  &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)},
+		head: &head{root: [32]byte{'A'}},
 	}
 	go func() {
 		require.NoError(t, s.saveHead(context.Background(), [32]byte{}))
@@ -38,9 +37,8 @@ func TestHeadRoot_DataRace(t *testing.T) {
 func TestHeadBlock_DataRace(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
 	s := &Service{
-		beaconDB: beaconDB,
-		head:     &head{block: &ethpb.SignedBeaconBlock{}},
-		stateGen: stategen.New(beaconDB),
+		cfg:  &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)},
+		head: &head{block: &ethpb.SignedBeaconBlock{}},
 	}
 	go func() {
 		require.NoError(t, s.saveHead(context.Background(), [32]byte{}))
@@ -52,8 +50,7 @@ func TestHeadBlock_DataRace(t *testing.T) {
 func TestHeadState_DataRace(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
 	s := &Service{
-		beaconDB: beaconDB,
-		stateGen: stategen.New(beaconDB),
+		cfg: &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)},
 	}
 	go func() {
 		require.NoError(t, s.saveHead(context.Background(), [32]byte{}))
--- a/beacon-chain/blockchain/chain_info_test.go
+++ b/beacon-chain/blockchain/chain_info_test.go
@@ -5,19 +5,19 @@ import (
 	"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/forkchoice/protoarray"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state"
+	"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"
+	"google.golang.org/protobuf/proto"
 )

 // Ensure Service implements chain info interface.
@@ -104,7 +104,7 @@ func TestPrevJustifiedCheckpt_GenesisRootOk(t *testing.T) {

 func TestHeadSlot_CanRetrieve(t *testing.T) {
 	c := &Service{}
-	s, err := state.InitializeFromProto(&pb.BeaconState{})
+	s, err := stateV0.InitializeFromProto(&pb.BeaconState{})
 	require.NoError(t, err)
 	c.head = &head{slot: 100, state: s}
 	assert.Equal(t, types.Slot(100), c.HeadSlot())
@@ -120,7 +120,7 @@ func TestHeadRoot_CanRetrieve(t *testing.T) {

 func TestHeadRoot_UseDB(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
-	c := &Service{beaconDB: beaconDB}
+	c := &Service{cfg: &Config{BeaconDB: beaconDB}}
 	c.head = &head{root: params.BeaconConfig().ZeroHash}
 	b := testutil.NewBeaconBlock()
 	br, err := b.Block.HashTreeRoot()
@@ -136,7 +136,7 @@ func TestHeadRoot_UseDB(t *testing.T) {
 func TestHeadBlock_CanRetrieve(t *testing.T) {
 	b := testutil.NewBeaconBlock()
 	b.Block.Slot = 1
-	s, err := state.InitializeFromProto(&pb.BeaconState{})
+	s, err := stateV0.InitializeFromProto(&pb.BeaconState{})
 	require.NoError(t, err)
 	c := &Service{}
 	c.head = &head{block: b, state: s}
@@ -147,7 +147,7 @@ func TestHeadBlock_CanRetrieve(t *testing.T) {
 }

 func TestHeadState_CanRetrieve(t *testing.T) {
-	s, err := state.InitializeFromProto(&pb.BeaconState{Slot: 2, GenesisValidatorsRoot: params.BeaconConfig().ZeroHash[:]})
+	s, err := stateV0.InitializeFromProto(&pb.BeaconState{Slot: 2, GenesisValidatorsRoot: params.BeaconConfig().ZeroHash[:]})
 	require.NoError(t, err)
 	c := &Service{}
 	c.head = &head{state: s}
@@ -164,7 +164,7 @@ func TestGenesisTime_CanRetrieve(t *testing.T) {

 func TestCurrentFork_CanRetrieve(t *testing.T) {
 	f := &pb.Fork{Epoch: 999}
-	s, err := state.InitializeFromProto(&pb.BeaconState{Fork: f})
+	s, err := stateV0.InitializeFromProto(&pb.BeaconState{Fork: f})
 	require.NoError(t, err)
 	c := &Service{}
 	c.head = &head{state: s}
@@ -189,7 +189,7 @@ func TestGenesisValidatorRoot_CanRetrieve(t *testing.T) {
 	c := &Service{}
 	assert.Equal(t, [32]byte{}, c.GenesisValidatorRoot(), "Did not get correct genesis validator root")

-	s, err := state.InitializeFromProto(&pb.BeaconState{GenesisValidatorsRoot: []byte{'a'}})
+	s, err := stateV0.InitializeFromProto(&pb.BeaconState{GenesisValidatorsRoot: []byte{'a'}})
 	require.NoError(t, err)
 	c.head = &head{state: s}
 	assert.Equal(t, [32]byte{'a'}, c.GenesisValidatorRoot(), "Did not get correct genesis validator root")
@@ -203,7 +203,7 @@ func TestHeadETH1Data_Nil(t *testing.T) {

 func TestHeadETH1Data_CanRetrieve(t *testing.T) {
 	d := &ethpb.Eth1Data{DepositCount: 999}
-	s, err := state.InitializeFromProto(&pb.BeaconState{Eth1Data: d})
+	s, err := stateV0.InitializeFromProto(&pb.BeaconState{Eth1Data: d})
 	require.NoError(t, err)
 	c := &Service{}
 	c.head = &head{state: s}
@@ -278,7 +278,21 @@ func TestService_HeadGenesisValidatorRoot(t *testing.T) {
 }

 func TestService_ProtoArrayStore(t *testing.T) {
-	c := &Service{forkChoiceStore: protoarray.New(0, 0, [32]byte{})}
+	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/head.go
+++ b/beacon-chain/blockchain/head.go
@@ -12,8 +12,8 @@ import (
 	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"
-	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"
@@ -25,7 +25,7 @@ type head struct {
 	slot  types.Slot               // current head slot.
 	root  [32]byte                 // current head root.
 	block *ethpb.SignedBeaconBlock // current head block.
-	state *stateTrie.BeaconState   // current head state.
+	state iface.BeaconState        // current head state.
 }

 // Determined the head from the fork choice service and saves its new data
@@ -58,18 +58,18 @@ func (s *Service) updateHead(ctx context.Context, balances []uint64) error {
 	// 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.forkChoiceStore.HasNode(headStartRoot) {
-		jb, err := s.beaconDB.Block(ctx, headStartRoot)
+	if !s.cfg.ForkChoiceStore.HasNode(headStartRoot) {
+		jb, err := s.cfg.BeaconDB.Block(ctx, headStartRoot)
 		if err != nil {
 			return err
 		}
-		s.forkChoiceStore = protoarray.New(j.Epoch, f.Epoch, bytesutil.ToBytes32(f.Root))
+		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
 		}
 	}

-	headRoot, err := s.forkChoiceStore.Head(ctx, j.Epoch, headStartRoot, balances, f.Epoch)
+	headRoot, err := s.cfg.ForkChoiceStore.Head(ctx, j.Epoch, headStartRoot, balances, f.Epoch)
 	if err != nil {
 		return err
 	}
@@ -95,12 +95,12 @@ func (s *Service) saveHead(ctx context.Context, headRoot [32]byte) error {

 	// If the head state is not available, just return nil.
 	// There's nothing to cache
-	if !s.beaconDB.HasStateSummary(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
 	}
@@ -109,11 +109,11 @@ 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")
 	}
-	if newHeadState == nil {
+	if newHeadState == nil || newHeadState.IsNil() {
 		return errors.New("cannot save nil head state")
 	}

@@ -124,7 +124,7 @@ func (s *Service) saveHead(ctx context.Context, headRoot [32]byte) error {
 			"newSlot": fmt.Sprintf("%d", newHeadBlock.Block.Slot),
 			"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,
@@ -139,7 +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")
 	}

@@ -149,7 +149,7 @@ 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, hs *stateTrie.BeaconState) error {
+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
 	}
@@ -161,12 +161,12 @@ func (s *Service) saveHeadNoDB(ctx context.Context, b *ethpb.SignedBeaconBlock,
 		return nil
 	}

-	s.setHeadInitialSync(r, stateTrie.CopySignedBeaconBlock(b), hs)
+	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 *stateTrie.BeaconState) {
+func (s *Service) setHead(root [32]byte, block *ethpb.SignedBeaconBlock, state iface.BeaconState) {
 	s.headLock.Lock()
 	defer s.headLock.Unlock()

@@ -174,7 +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(),
 	}
 }
@@ -182,7 +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 *stateTrie.BeaconState) {
+func (s *Service) setHeadInitialSync(root [32]byte, block *ethpb.SignedBeaconBlock, state iface.BeaconState) {
 	s.headLock.Lock()
 	defer s.headLock.Unlock()

@@ -190,7 +190,7 @@ 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,
 	}
 }
@@ -216,13 +216,13 @@ func (s *Service) headRoot() [32]byte {
 // It does a full copy on head block for immutability.
 // This is a lock free version.
 func (s *Service) headBlock() *ethpb.SignedBeaconBlock {
-	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.
 // This is a lock free version.
-func (s *Service) headState(ctx context.Context) *stateTrie.BeaconState {
+func (s *Service) headState(ctx context.Context) iface.BeaconState {
 	ctx, span := trace.StartSpan(ctx, "blockChain.headState")
 	defer span.End()

@@ -243,26 +243,26 @@ func (s *Service) hasHeadState() bool {

 // 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()

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

--- a/beacon-chain/blockchain/head_test.go
+++ b/beacon-chain/blockchain/head_test.go
@@ -39,14 +39,14 @@ func TestSaveHead_Different(t *testing.T) {
 	newHeadSignedBlock.Block.Slot = 1
 	newHeadBlock := newHeadSignedBlock.Block

-	require.NoError(t, service.beaconDB.SaveBlock(context.Background(), newHeadSignedBlock))
+	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.beaconDB.SaveStateSummary(context.Background(), &pb.StateSummary{Slot: 1, Root: newRoot[:]}))
-	require.NoError(t, service.beaconDB.SaveState(context.Background(), headState, newRoot))
+	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))

 	assert.Equal(t, types.Slot(1), service.HeadSlot(), "Head did not change")
@@ -73,14 +73,14 @@ func TestSaveHead_Different_Reorg(t *testing.T) {
 	newHeadSignedBlock.Block.ParentRoot = reorgChainParent[:]
 	newHeadBlock := newHeadSignedBlock.Block

-	require.NoError(t, service.beaconDB.SaveBlock(context.Background(), newHeadSignedBlock))
+	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.beaconDB.SaveStateSummary(context.Background(), &pb.StateSummary{Slot: 1, Root: newRoot[:]}))
-	require.NoError(t, service.beaconDB.SaveState(context.Background(), headState, newRoot))
+	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))

 	assert.Equal(t, types.Slot(1), service.HeadSlot(), "Head did not change")
@@ -101,8 +101,8 @@ func TestCacheJustifiedStateBalances_CanCache(t *testing.T) {

 	state, _ := testutil.DeterministicGenesisState(t, 100)
 	r := [32]byte{'a'}
-	require.NoError(t, service.beaconDB.SaveStateSummary(context.Background(), &pb.StateSummary{Root: r[:]}))
-	require.NoError(t, service.beaconDB.SaveState(context.Background(), state, r))
+	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")
 }
@@ -112,7 +112,7 @@ func TestUpdateHead_MissingJustifiedRoot(t *testing.T) {
 	service := setupBeaconChain(t, beaconDB)

 	b := testutil.NewBeaconBlock()
-	require.NoError(t, service.beaconDB.SaveBlock(context.Background(), b))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(context.Background(), b))
 	r, err := b.Block.HashTreeRoot()
 	require.NoError(t, err)

--- a/beacon-chain/blockchain/info.go
+++ b/beacon-chain/blockchain/info.go
@@ -39,13 +39,13 @@ func (s *Service) TreeHandler(w http.ResponseWriter, r *http.Request) {
 		log.WithError(err).Error("Could not get head state")
 		return
 	}
-	if headState == nil {
+	if headState == nil || headState.IsNil() {
 		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")
--- a/beacon-chain/blockchain/info_test.go
+++ b/beacon-chain/blockchain/info_test.go
@@ -35,8 +35,8 @@ func TestService_TreeHandler(t *testing.T) {
 	}
 	s, err := NewService(ctx, cfg)
 	require.NoError(t, err)
-	require.NoError(t, s.forkChoiceStore.ProcessBlock(ctx, 0, [32]byte{'a'}, [32]byte{'g'}, [32]byte{'c'}, 0, 0))
-	require.NoError(t, s.forkChoiceStore.ProcessBlock(ctx, 1, [32]byte{'b'}, [32]byte{'a'}, [32]byte{'c'}, 0, 0))
+	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()
--- 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/metrics.go
+++ b/beacon-chain/blockchain/metrics.go
@@ -8,7 +8,7 @@ import (
 	types "github.com/prysmaticlabs/eth2-types"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/epoch/precompute"
-	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"
 )
@@ -120,7 +120,7 @@ func reportSlotMetrics(stateSlot, headSlot, clockSlot types.Slot, finalizedCheck
 }

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

 	// Validator instances
--- a/beacon-chain/blockchain/metrics_test.go
+++ b/beacon-chain/blockchain/metrics_test.go
@@ -25,7 +25,7 @@ func TestReportEpochMetrics_BadAttestation(t *testing.T) {
 	require.NoError(t, err)
 	h, err := testutil.NewBeaconState()
 	require.NoError(t, err)
-	require.NoError(t, h.SetCurrentEpochAttestations([]*pb.PendingAttestation{{InclusionDelay: 0}}))
+	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)
 }
@@ -36,7 +36,7 @@ func TestReportEpochMetrics_SlashedValidatorOutOfBound(t *testing.T) {
 	require.NoError(t, err)
 	v.Slashed = true
 	require.NoError(t, h.UpdateValidatorAtIndex(0, v))
-	require.NoError(t, h.SetCurrentEpochAttestations([]*pb.PendingAttestation{{InclusionDelay: 1, Data: testutil.HydrateAttestationData(&eth.AttestationData{})}}))
+	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
@@ -6,7 +6,7 @@ import (
 	"github.com/pkg/errors"
 	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/stateV0"
 	"github.com/prysmaticlabs/prysm/shared/attestationutil"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
@@ -46,7 +46,7 @@ func (s *Service) onAttestation(ctx context.Context, a *ethpb.Attestation) error
 	if err := helpers.ValidateSlotTargetEpoch(a.Data); err != nil {
 		return err
 	}
-	tgt := stateTrie.CopyCheckpoint(a.Data.Target)
+	tgt := stateV0.CopyCheckpoint(a.Data.Target)

 	// 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
@@ -97,7 +97,7 @@ func (s *Service) onAttestation(ctx context.Context, a *ethpb.Attestation) error
 	// 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 nil
 }
--- a/beacon-chain/blockchain/process_attestation_helpers.go
+++ b/beacon-chain/blockchain/process_attestation_helpers.go
@@ -10,7 +10,7 @@ import (
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/state"
-	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/featureconfig"
 	"github.com/prysmaticlabs/prysm/shared/mputil"
@@ -18,7 +18,7 @@ import (
 )

 // 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) {
+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 */)
@@ -29,11 +29,11 @@ func (s *Service) getAttPreState(ctx context.Context, c *ethpb.Checkpoint) (*sta
 	if err != nil {
 		return nil, errors.Wrap(err, "could not get cached checkpoint state")
 	}
-	if cachedState != nil {
+	if cachedState != nil && !cachedState.IsNil() {
 		return cachedState, nil
 	}

-	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 epoch %d", c.Epoch)
 	}
@@ -62,7 +62,7 @@ func (s *Service) getAttPreState(ctx context.Context, c *ethpb.Checkpoint) (*sta

 	// 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.stateGen.HasStateInCache(ctx, bytesutil.ToBytes32(c.Root))
+	has, err := s.cfg.StateGen.HasStateInCache(ctx, bytesutil.ToBytes32(c.Root))
 	if err != nil {
 		return nil, err
 	}
@@ -93,7 +93,7 @@ func (s *Service) verifyAttTargetEpoch(_ context.Context, genesisTime, nowTime u
 // verifyBeaconBlock verifies beacon head block is known and not from the future.
 func (s *Service) verifyBeaconBlock(ctx context.Context, data *ethpb.AttestationData) error {
 	r := bytesutil.ToBytes32(data.BeaconBlockRoot)
-	b, err := s.beaconDB.Block(ctx, r)
+	b, err := s.cfg.BeaconDB.Block(ctx, r)
 	if err != nil {
 		return err
 	}
--- a/beacon-chain/blockchain/process_attestation_test.go
+++ b/beacon-chain/blockchain/process_attestation_test.go
@@ -50,7 +50,7 @@ func TestStore_OnAttestation_ErrorConditions(t *testing.T) {
 	s, err := testutil.NewBeaconState()
 	require.NoError(t, err)
 	require.NoError(t, s.SetSlot(100*params.BeaconConfig().SlotsPerEpoch))
-	require.NoError(t, service.beaconDB.SaveState(ctx, s, BlkWithStateBadAttRoot))
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, s, BlkWithStateBadAttRoot))

 	BlkWithValidState := testutil.NewBeaconBlock()
 	BlkWithValidState.Block.Slot = 2
@@ -66,7 +66,7 @@ func TestStore_OnAttestation_ErrorConditions(t *testing.T) {
 		PreviousVersion: params.BeaconConfig().GenesisForkVersion,
 	})
 	require.NoError(t, err)
-	require.NoError(t, service.beaconDB.SaveState(ctx, s, BlkWithValidStateRoot))
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, s, BlkWithValidStateRoot))

 	tests := []struct {
 		name      string
@@ -146,8 +146,8 @@ func TestStore_OnAttestation_Ok(t *testing.T) {
 	copied := genesisState.Copy()
 	copied, err = state.ProcessSlots(ctx, copied, 1)
 	require.NoError(t, err)
-	require.NoError(t, service.beaconDB.SaveState(ctx, copied, tRoot))
-	require.NoError(t, service.forkChoiceStore.ProcessBlock(ctx, 0, tRoot, tRoot, tRoot, 1, 1))
+	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]))
 }

@@ -175,7 +175,7 @@ func TestStore_SaveCheckpointState(t *testing.T) {
 	err = s.SetBalances([]uint64{0})
 	require.NoError(t, err)
 	r := [32]byte{'g'}
-	require.NoError(t, service.beaconDB.SaveState(ctx, s, r))
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, s, r))

 	service.justifiedCheckpt = &ethpb.Checkpoint{Root: r[:]}
 	service.bestJustifiedCheckpt = &ethpb.Checkpoint{Root: r[:]}
@@ -184,16 +184,16 @@ func TestStore_SaveCheckpointState(t *testing.T) {

 	r = bytesutil.ToBytes32([]byte{'A'})
 	cp1 := &ethpb.Checkpoint{Epoch: 1, Root: bytesutil.PadTo([]byte{'A'}, 32)}
-	require.NoError(t, service.beaconDB.SaveState(ctx, s, bytesutil.ToBytes32([]byte{'A'})))
-	require.NoError(t, service.beaconDB.SaveStateSummary(ctx, &pb.StateSummary{Root: bytesutil.PadTo([]byte{'A'}, 32)}))
+	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)
 	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)}
-	require.NoError(t, service.beaconDB.SaveState(ctx, s, bytesutil.ToBytes32([]byte{'B'})))
-	require.NoError(t, service.beaconDB.SaveStateSummary(ctx, &pb.StateSummary{Root: bytesutil.PadTo([]byte{'B'}, 32)}))
+	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)
 	require.NoError(t, err)
 	assert.Equal(t, 2*params.BeaconConfig().SlotsPerEpoch, s2.Slot(), "Unexpected state slot")
@@ -216,8 +216,8 @@ func TestStore_SaveCheckpointState(t *testing.T) {
 	service.finalizedCheckpt = &ethpb.Checkpoint{Root: r[:]}
 	service.prevFinalizedCheckpt = &ethpb.Checkpoint{Root: r[:]}
 	cp3 := &ethpb.Checkpoint{Epoch: 1, Root: bytesutil.PadTo([]byte{'C'}, 32)}
-	require.NoError(t, service.beaconDB.SaveState(ctx, s, bytesutil.ToBytes32([]byte{'C'})))
-	require.NoError(t, service.beaconDB.SaveStateSummary(ctx, &pb.StateSummary{Root: bytesutil.PadTo([]byte{'C'}, 32)}))
+	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)
 	require.NoError(t, err)
 	assert.Equal(t, s.Slot(), s3.Slot(), "Unexpected state slot")
@@ -237,7 +237,7 @@ func TestStore_UpdateCheckpointState(t *testing.T) {
 	epoch := types.Epoch(1)
 	baseState, _ := testutil.DeterministicGenesisState(t, 1)
 	checkpoint := &ethpb.Checkpoint{Epoch: epoch, Root: bytesutil.PadTo([]byte("hi"), 32)}
-	require.NoError(t, service.beaconDB.SaveState(ctx, baseState, bytesutil.ToBytes32(checkpoint.Root)))
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, baseState, bytesutil.ToBytes32(checkpoint.Root)))
 	returned, err := service.getAttPreState(ctx, checkpoint)
 	require.NoError(t, err)
 	assert.Equal(t, params.BeaconConfig().SlotsPerEpoch.Mul(uint64(checkpoint.Epoch)), returned.Slot(), "Incorrectly returned base state")
@@ -248,7 +248,7 @@ func TestStore_UpdateCheckpointState(t *testing.T) {

 	epoch = 2
 	newCheckpoint := &ethpb.Checkpoint{Epoch: epoch, Root: bytesutil.PadTo([]byte("bye"), 32)}
-	require.NoError(t, service.beaconDB.SaveState(ctx, baseState, bytesutil.ToBytes32(newCheckpoint.Root)))
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, baseState, bytesutil.ToBytes32(newCheckpoint.Root)))
 	returned, err = service.getAttPreState(ctx, newCheckpoint)
 	require.NoError(t, err)
 	s, err := helpers.StartSlot(newCheckpoint.Epoch)
@@ -321,7 +321,7 @@ func TestVerifyBeaconBlock_futureBlock(t *testing.T) {

 	b := testutil.NewBeaconBlock()
 	b.Block.Slot = 2
-	require.NoError(t, service.beaconDB.SaveBlock(ctx, b))
+	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[:]}
@@ -339,7 +339,7 @@ func TestVerifyBeaconBlock_OK(t *testing.T) {

 	b := testutil.NewBeaconBlock()
 	b.Block.Slot = 2
-	require.NoError(t, service.beaconDB.SaveBlock(ctx, b))
+	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[:]}
@@ -357,7 +357,7 @@ func TestVerifyFinalizedConsistency_InconsistentRoot(t *testing.T) {

 	b32 := testutil.NewBeaconBlock()
 	b32.Block.Slot = 32
-	require.NoError(t, service.beaconDB.SaveBlock(ctx, b32))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, b32))
 	r32, err := b32.Block.HashTreeRoot()
 	require.NoError(t, err)

@@ -366,7 +366,7 @@ func TestVerifyFinalizedConsistency_InconsistentRoot(t *testing.T) {
 	b33 := testutil.NewBeaconBlock()
 	b33.Block.Slot = 33
 	b33.Block.ParentRoot = r32[:]
-	require.NoError(t, service.beaconDB.SaveBlock(ctx, b33))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, b33))
 	r33, err := b33.Block.HashTreeRoot()
 	require.NoError(t, err)

@@ -384,7 +384,7 @@ func TestVerifyFinalizedConsistency_OK(t *testing.T) {

 	b32 := testutil.NewBeaconBlock()
 	b32.Block.Slot = 32
-	require.NoError(t, service.beaconDB.SaveBlock(ctx, b32))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, b32))
 	r32, err := b32.Block.HashTreeRoot()
 	require.NoError(t, err)

@@ -393,7 +393,7 @@ func TestVerifyFinalizedConsistency_OK(t *testing.T) {
 	b33 := testutil.NewBeaconBlock()
 	b33.Block.Slot = 33
 	b33.Block.ParentRoot = r32[:]
-	require.NoError(t, service.beaconDB.SaveBlock(ctx, b33))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, b33))
 	r33, err := b33.Block.HashTreeRoot()
 	require.NoError(t, err)

@@ -422,10 +422,10 @@ func TestVerifyFinalizedConsistency_IsCanonical(t *testing.T) {
 	r33, err := b33.Block.HashTreeRoot()
 	require.NoError(t, err)

-	require.NoError(t, service.forkChoiceStore.ProcessBlock(ctx, b32.Block.Slot, r32, [32]byte{}, [32]byte{}, 0, 0))
-	require.NoError(t, service.forkChoiceStore.ProcessBlock(ctx, b33.Block.Slot, r33, r32, [32]byte{}, 0, 0))
+	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.forkChoiceStore.Head(ctx, 0, r32, []uint64{}, 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
@@ -11,7 +11,7 @@ import (
 	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"
-	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"
@@ -51,7 +51,8 @@ var initialSyncBlockCacheSize = uint64(2 * params.BeaconConfig().SlotsPerEpoch)
 //    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, signed_block, True)
+//    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
@@ -94,16 +95,9 @@ func (s *Service) onBlock(ctx context.Context, signed *ethpb.SignedBeaconBlock,
 		return err
 	}

-	set, postState, err := state.ExecuteStateTransitionNoVerifyAnySig(ctx, preState, signed)
+	postState, err := state.ExecuteStateTransition(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")
+		return err
 	}

 	if err := s.savePostStateInfo(ctx, blockRoot, signed, postState, false /* reg sync */); err != nil {
@@ -146,7 +140,7 @@ func (s *Service) onBlock(ctx context.Context, signed *ethpb.SignedBeaconBlock,
 		}

 		// Send notification of the processed block to the state feed.
-		s.stateNotifier.StateFeed().Send(&feed.Event{
+		s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
 			Type: statefeed.BlockProcessed,
 			Data: &statefeed.BlockProcessedData{
 				Slot:        signed.Block.Slot,
@@ -163,7 +157,7 @@ func (s *Service) onBlock(ctx context.Context, signed *ethpb.SignedBeaconBlock,
 			return err
 		}
 		fRoot := bytesutil.ToBytes32(postState.FinalizedCheckpoint().Root)
-		if err := s.forkChoiceStore.Prune(ctx, fRoot); err != nil {
+		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 {
@@ -205,11 +199,11 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []*ethpb.SignedBeaconBl
 	if err := s.verifyBlkPreState(ctx, b); err != nil {
 		return nil, nil, err
 	}
-	preState, err := s.stateGen.StateByRootInitialSync(ctx, bytesutil.ToBytes32(b.ParentRoot))
+	preState, err := s.cfg.StateGen.StateByRootInitialSync(ctx, bytesutil.ToBytes32(b.ParentRoot))
 	if err != nil {
 		return nil, nil, err
 	}
-	if preState == nil {
+	if preState == nil || preState.IsNil() {
 		return nil, nil, fmt.Errorf("nil pre state for slot %d", b.Slot)
 	}

@@ -221,7 +215,7 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []*ethpb.SignedBeaconBl
 		Messages:   [][32]byte{},
 	}
 	var set *bls.SignatureSet
-	boundaries := make(map[[32]byte]*stateTrie.BeaconState)
+	boundaries := make(map[[32]byte]iface.BeaconState)
 	for i, b := range blks {
 		set, preState, err = state.ExecuteStateTransitionNoVerifyAnySig(ctx, preState, b)
 		if err != nil {
@@ -246,14 +240,14 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []*ethpb.SignedBeaconBl
 		return nil, nil, errors.New("batch block signature verification failed")
 	}
 	for r, st := range boundaries {
-		if err := s.stateGen.SaveState(ctx, r, st); err != nil {
+		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.stateGen.SaveState(ctx, lastBR, preState); err != nil {
+	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 {
@@ -272,7 +266,7 @@ func (s *Service) handleBlockAfterBatchVerify(ctx context.Context, signed *ethpb
 	if err := s.insertBlockToForkChoiceStore(ctx, b, blockRoot, fCheckpoint, jCheckpoint); err != nil {
 		return err
 	}
-	if err := s.beaconDB.SaveStateSummary(ctx, &pb.StateSummary{
+	if err := s.cfg.BeaconDB.SaveStateSummary(ctx, &pb.StateSummary{
 		Slot: signed.Block.Slot,
 		Root: blockRoot[:],
 	}); err != nil {
@@ -281,7 +275,7 @@ func (s *Service) handleBlockAfterBatchVerify(ctx context.Context, signed *ethpb

 	// 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()
@@ -303,7 +297,7 @@ func (s *Service) handleBlockAfterBatchVerify(ctx context.Context, signed *ethpb
 }

 // Epoch boundary bookkeeping such as logging epoch summaries.
-func (s *Service) handleEpochBoundary(ctx context.Context, postState *stateTrie.BeaconState) error {
+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 {
@@ -343,7 +337,7 @@ func (s *Service) handleEpochBoundary(ctx context.Context, postState *stateTrie.
 // 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) insertBlockAndAttestationsToForkChoiceStore(ctx context.Context, blk *ethpb.BeaconBlock, root [32]byte,
-	st *stateTrie.BeaconState) error {
+	st iface.BeaconState) error {
 	fCheckpoint := st.FinalizedCheckpoint()
 	jCheckpoint := st.CurrentJustifiedCheckpoint()
 	if err := s.insertBlockToForkChoiceStore(ctx, blk, root, fCheckpoint, jCheckpoint); err != nil {
@@ -359,7 +353,7 @@ func (s *Service) insertBlockAndAttestationsToForkChoiceStore(ctx context.Contex
 		if err != nil {
 			return err
 		}
-		s.forkChoiceStore.ProcessAttestation(ctx, indices, bytesutil.ToBytes32(a.Data.BeaconBlockRoot), a.Data.Target.Epoch)
+		s.cfg.ForkChoiceStore.ProcessAttestation(ctx, indices, bytesutil.ToBytes32(a.Data.BeaconBlockRoot), a.Data.Target.Epoch)
 	}
 	return nil
 }
@@ -370,7 +364,7 @@ func (s *Service) insertBlockToForkChoiceStore(ctx context.Context, blk *ethpb.B
 		return err
 	}
 	// Feed in block to fork choice store.
-	if err := s.forkChoiceStore.ProcessBlock(ctx,
+	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 {
@@ -381,15 +375,15 @@ func (s *Service) insertBlockToForkChoiceStore(ctx context.Context, blk *ethpb.B

 // 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 *stateTrie.BeaconState, initSync bool) error {
+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.beaconDB.SaveBlock(ctx, b); err != nil {
+	} 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.stateGen.SaveState(ctx, r, st); err != nil {
+	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 {
--- a/beacon-chain/blockchain/process_block_helpers.go
+++ b/beacon-chain/blockchain/process_block_helpers.go
@@ -9,7 +9,7 @@ import (
 	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"
+	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"
@@ -26,7 +26,7 @@ func (s *Service) CurrentSlot() types.Slot {
 // 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) {
+func (s *Service) getBlockPreState(ctx context.Context, b *ethpb.BeaconBlock) (iface.BeaconState, error) {
 	ctx, span := trace.StartSpan(ctx, "blockChain.getBlockPreState")
 	defer span.End()

@@ -35,11 +35,11 @@ func (s *Service) getBlockPreState(ctx context.Context, b *ethpb.BeaconBlock) (*
 		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)
 	}
-	if preState == nil {
+	if preState == nil || preState.IsNil() {
 		return nil, errors.Wrapf(err, "nil pre state for slot %d", b.Slot)
 	}

@@ -65,7 +65,7 @@ func (s *Service) verifyBlkPreState(ctx context.Context, b *ethpb.BeaconBlock) e
 	// 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.beaconDB.HasStateSummary(ctx, parentRoot) && !s.beaconDB.HasBlock(ctx, parentRoot) {
+	if !s.cfg.BeaconDB.HasStateSummary(ctx, parentRoot) && !s.cfg.BeaconDB.HasBlock(ctx, parentRoot) {
 		return errors.New("could not reconstruct parent state")
 	}

@@ -73,12 +73,12 @@ func (s *Service) verifyBlkPreState(ctx context.Context, b *ethpb.BeaconBlock) e
 		return err
 	}

-	has, err := s.stateGen.HasState(ctx, parentRoot)
+	has, err := s.cfg.StateGen.HasState(ctx, parentRoot)
 	if err != nil {
 		return err
 	}
 	if !has {
-		if err := s.beaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
+		if err := s.cfg.BeaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
 			return errors.Wrap(err, "could not save initial sync blocks")
 		}
 		s.clearInitSyncBlocks()
@@ -92,7 +92,7 @@ func (s *Service) VerifyBlkDescendant(ctx context.Context, root [32]byte) error
 	ctx, span := trace.StartSpan(ctx, "blockChain.VerifyBlkDescendant")
 	defer span.End()
 	fRoot := s.ensureRootNotZeros(bytesutil.ToBytes32(s.finalizedCheckpt.Root))
-	finalizedBlkSigned, err := s.beaconDB.Block(ctx, fRoot)
+	finalizedBlkSigned, err := s.cfg.BeaconDB.Block(ctx, fRoot)
 	if err != nil {
 		return err
 	}
@@ -145,7 +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
 		}
@@ -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 +205,7 @@ 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,
@@ -218,18 +218,18 @@ func (s *Service) updateJustifiedInitSync(ctx context.Context, cp *ethpb.Checkpo
 		return err
 	}

-	return s.beaconDB.SaveJustifiedCheckpoint(ctx, cp)
+	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.beaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
+	if err := s.cfg.BeaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
 		return err
 	}
 	s.clearInitSyncBlocks()

-	if err := s.beaconDB.SaveFinalizedCheckpoint(ctx, cp); err != nil {
+	if err := s.cfg.BeaconDB.SaveFinalizedCheckpoint(ctx, cp); err != nil {
 		return err
 	}
 	if !featureconfig.Get().UpdateHeadTimely {
@@ -238,7 +238,7 @@ func (s *Service) updateFinalized(ctx context.Context, cp *ethpb.Checkpoint) err
 	}

 	fRoot := bytesutil.ToBytes32(cp.Root)
-	if err := s.stateGen.MigrateToCold(ctx, fRoot); err != nil {
+	if err := s.cfg.StateGen.MigrateToCold(ctx, fRoot); err != nil {
 		return errors.Wrap(err, "could not migrate to cold")
 	}

@@ -282,10 +282,10 @@ func (s *Service) ancestorByForkChoiceStore(ctx context.Context, r [32]byte, slo
 	ctx, span := trace.StartSpan(ctx, "blockChain.ancestorByForkChoiceStore")
 	defer span.End()

-	if !s.forkChoiceStore.HasParent(r) {
+	if !s.cfg.ForkChoiceStore.HasParent(r) {
 		return nil, errors.New("could not find root in fork choice store")
 	}
-	return s.forkChoiceStore.AncestorRoot(ctx, r, slot)
+	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`.
@@ -298,7 +298,7 @@ func (s *Service) ancestorByDB(ctx context.Context, r [32]byte, slot types.Slot)
 		return nil, ctx.Err()
 	}

-	signed, err := s.beaconDB.Block(ctx, r)
+	signed, err := s.cfg.BeaconDB.Block(ctx, r)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not get ancestor block")
 	}
@@ -333,7 +333,7 @@ func (s *Service) ancestorByDB(ctx context.Context, r [32]byte, slot types.Slot)
 //            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 {
@@ -377,8 +377,8 @@ func (s *Service) fillInForkChoiceMissingBlocks(ctx context.Context, blk *ethpb.
 	}
 	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
 		}
@@ -396,7 +396,7 @@ func (s *Service) fillInForkChoiceMissingBlocks(ctx context.Context, blk *ethpb.
 	for i := len(pendingNodes) - 1; i >= 0; i-- {
 		b := pendingNodes[i]
 		r := pendingRoots[i]
-		if err := s.forkChoiceStore.ProcessBlock(ctx,
+		if err := s.cfg.ForkChoiceStore.ProcessBlock(ctx,
 			b.Slot, r, bytesutil.ToBytes32(b.ParentRoot), bytesutil.ToBytes32(b.Body.Graffiti),
 			jCheckpoint.Epoch,
 			fCheckpoint.Epoch); err != nil {
@@ -413,7 +413,7 @@ func (s *Service) insertFinalizedDeposits(ctx context.Context, fRoot [32]byte) e
 	defer span.End()

 	// Update deposit cache.
-	finalizedState, err := s.stateGen.StateByRoot(ctx, fRoot)
+	finalizedState, err := s.cfg.StateGen.StateByRoot(ctx, fRoot)
 	if err != nil {
 		return errors.Wrap(err, "could not fetch finalized state")
 	}
@@ -421,9 +421,9 @@ func (s *Service) insertFinalizedDeposits(ctx context.Context, fRoot [32]byte) e
 	// 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.depositCache.InsertFinalizedDeposits(ctx, eth1DepositIndex)
+	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.depositCache.PruneProofs(ctx, eth1DepositIndex); err != nil {
+	if err = s.cfg.DepositCache.PruneProofs(ctx, eth1DepositIndex); err != nil {
 		return errors.Wrap(err, "could not prune deposit proofs")
 	}
 	return nil
@@ -433,11 +433,11 @@ func (s *Service) insertFinalizedDeposits(ctx context.Context, fRoot [32]byte) e
 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
@@ -17,7 +17,8 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/db"
 	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"
+	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"
 	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
 	"github.com/prysmaticlabs/prysm/shared/attestationutil"
@@ -47,7 +48,7 @@ func TestStore_OnBlock(t *testing.T) {
 	require.NoError(t, err)
 	st, err := testutil.NewBeaconState()
 	require.NoError(t, err)
-	require.NoError(t, service.beaconDB.SaveState(ctx, st.Copy(), validGenesisRoot))
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, st.Copy(), validGenesisRoot))
 	roots, err := blockTree1(t, beaconDB, validGenesisRoot[:])
 	require.NoError(t, err)
 	random := testutil.NewBeaconBlock()
@@ -56,16 +57,16 @@ func TestStore_OnBlock(t *testing.T) {
 	assert.NoError(t, beaconDB.SaveBlock(ctx, random))
 	randomParentRoot, err := random.Block.HashTreeRoot()
 	assert.NoError(t, err)
-	require.NoError(t, service.beaconDB.SaveStateSummary(ctx, &pb.StateSummary{Slot: st.Slot(), Root: randomParentRoot[:]}))
-	require.NoError(t, service.beaconDB.SaveState(ctx, st.Copy(), randomParentRoot))
+	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(ctx, &pb.StateSummary{Slot: st.Slot(), Root: randomParentRoot[:]}))
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, st.Copy(), randomParentRoot))
 	randomParentRoot2 := roots[1]
-	require.NoError(t, service.beaconDB.SaveStateSummary(ctx, &pb.StateSummary{Slot: st.Slot(), Root: randomParentRoot2}))
-	require.NoError(t, service.beaconDB.SaveState(ctx, st.Copy(), bytesutil.ToBytes32(randomParentRoot2)))
+	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(ctx, &pb.StateSummary{Slot: st.Slot(), Root: randomParentRoot2}))
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, st.Copy(), bytesutil.ToBytes32(randomParentRoot2)))

 	tests := []struct {
 		name          string
 		blk           *ethpb.SignedBeaconBlock
-		s             *stateTrie.BeaconState
+		s             iface.BeaconState
 		time          uint64
 		wantErrString string
 	}{
@@ -144,7 +145,7 @@ func TestStore_OnBlockBatch(t *testing.T) {
 	service.finalizedCheckpt = &ethpb.Checkpoint{
 		Root: gRoot[:],
 	}
-	service.forkChoiceStore = protoarray.New(0, 0, [32]byte{})
+	service.cfg.ForkChoiceStore = protoarray.New(0, 0, [32]byte{})
 	service.saveInitSyncBlock(gRoot, genesis)

 	st, keys := testutil.DeterministicGenesisState(t, 64)
@@ -153,7 +154,7 @@ func TestStore_OnBlockBatch(t *testing.T) {

 	var blks []*ethpb.SignedBeaconBlock
 	var blkRoots [][32]byte
-	var firstState *stateTrie.BeaconState
+	var firstState iface.BeaconState
 	for i := 1; i < 10; i++ {
 		b, err := testutil.GenerateFullBlock(bState, keys, testutil.DefaultBlockGenConfig(), types.Slot(i))
 		require.NoError(t, err)
@@ -171,7 +172,7 @@ func TestStore_OnBlockBatch(t *testing.T) {

 	blks[0].Block.ParentRoot = gRoot[:]
 	require.NoError(t, beaconDB.SaveBlock(context.Background(), blks[0]))
-	require.NoError(t, service.stateGen.SaveState(ctx, blkRoots[0], firstState))
+	require.NoError(t, service.cfg.StateGen.SaveState(ctx, blkRoots[0], firstState))
 	_, _, err = service.onBlockBatch(ctx, blks[1:], blkRoots[1:])
 	require.NoError(t, err)
 }
@@ -199,8 +200,8 @@ func TestRemoveStateSinceLastFinalized_EmptyStartSlot(t *testing.T) {
 	newJustifiedBlk.Block.ParentRoot = bytesutil.PadTo(lastJustifiedRoot[:], 32)
 	newJustifiedRoot, err := newJustifiedBlk.Block.HashTreeRoot()
 	require.NoError(t, err)
-	require.NoError(t, service.beaconDB.SaveBlock(ctx, newJustifiedBlk))
-	require.NoError(t, service.beaconDB.SaveBlock(ctx, lastJustifiedBlk))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, newJustifiedBlk))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, lastJustifiedBlk))

 	diff := params.BeaconConfig().SlotsPerEpoch.Sub(1).Mul(params.BeaconConfig().SecondsPerSlot)
 	service.genesisTime = time.Unix(time.Now().Unix()-int64(diff), 0)
@@ -227,8 +228,8 @@ func TestShouldUpdateJustified_ReturnFalse(t *testing.T) {
 	newJustifiedBlk.Block.ParentRoot = bytesutil.PadTo(lastJustifiedRoot[:], 32)
 	newJustifiedRoot, err := newJustifiedBlk.Block.HashTreeRoot()
 	require.NoError(t, err)
-	require.NoError(t, service.beaconDB.SaveBlock(ctx, newJustifiedBlk))
-	require.NoError(t, service.beaconDB.SaveBlock(ctx, lastJustifiedBlk))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, newJustifiedBlk))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, lastJustifiedBlk))

 	diff := params.BeaconConfig().SlotsPerEpoch.Sub(1).Mul(params.BeaconConfig().SecondsPerSlot)
 	service.genesisTime = time.Unix(time.Now().Unix()-int64(diff), 0)
@@ -250,7 +251,7 @@ func TestCachedPreState_CanGetFromStateSummary(t *testing.T) {
 	service, err := NewService(ctx, cfg)
 	require.NoError(t, err)

-	s, err := stateTrie.InitializeFromProto(&pb.BeaconState{Slot: 1, GenesisValidatorsRoot: params.BeaconConfig().ZeroHash[:]})
+	s, err := stateV0.InitializeFromProto(&pb.BeaconState{Slot: 1, GenesisValidatorsRoot: params.BeaconConfig().ZeroHash[:]})
 	require.NoError(t, err)

 	genesisStateRoot := [32]byte{}
@@ -261,14 +262,14 @@ func TestCachedPreState_CanGetFromStateSummary(t *testing.T) {
 	service.finalizedCheckpt = &ethpb.Checkpoint{
 		Root: gRoot[:],
 	}
-	service.forkChoiceStore = protoarray.New(0, 0, [32]byte{})
+	service.cfg.ForkChoiceStore = protoarray.New(0, 0, [32]byte{})
 	service.saveInitSyncBlock(gRoot, genesis)

 	b := testutil.NewBeaconBlock()
 	b.Block.Slot = 1
 	b.Block.ParentRoot = gRoot[:]
-	require.NoError(t, service.beaconDB.SaveStateSummary(ctx, &pb.StateSummary{Slot: 1, Root: gRoot[:]}))
-	require.NoError(t, service.stateGen.SaveState(ctx, gRoot, s))
+	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(ctx, &pb.StateSummary{Slot: 1, Root: gRoot[:]}))
+	require.NoError(t, service.cfg.StateGen.SaveState(ctx, gRoot, s))
 	require.NoError(t, service.verifyBlkPreState(ctx, b.Block))
 }

@@ -291,7 +292,7 @@ func TestCachedPreState_CanGetFromDB(t *testing.T) {
 	service.finalizedCheckpt = &ethpb.Checkpoint{
 		Root: gRoot[:],
 	}
-	service.forkChoiceStore = protoarray.New(0, 0, [32]byte{})
+	service.cfg.ForkChoiceStore = protoarray.New(0, 0, [32]byte{})
 	service.saveInitSyncBlock(gRoot, genesis)

 	b := testutil.NewBeaconBlock()
@@ -302,10 +303,10 @@ func TestCachedPreState_CanGetFromDB(t *testing.T) {
 	assert.ErrorContains(t, wanted, err)

 	b.Block.ParentRoot = gRoot[:]
-	s, err := stateTrie.InitializeFromProto(&pb.BeaconState{Slot: 1})
+	s, err := stateV0.InitializeFromProto(&pb.BeaconState{Slot: 1})
 	require.NoError(t, err)
-	require.NoError(t, service.beaconDB.SaveStateSummary(ctx, &pb.StateSummary{Slot: 1, Root: gRoot[:]}))
-	require.NoError(t, service.stateGen.SaveState(ctx, gRoot, s))
+	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(ctx, &pb.StateSummary{Slot: 1, Root: gRoot[:]}))
+	require.NoError(t, service.cfg.StateGen.SaveState(ctx, gRoot, s))
 	require.NoError(t, service.verifyBlkPreState(ctx, b.Block))
 }

@@ -349,7 +350,7 @@ func TestFillForkChoiceMissingBlocks_CanSave(t *testing.T) {
 	cfg := &Config{BeaconDB: beaconDB}
 	service, err := NewService(ctx, cfg)
 	require.NoError(t, err)
-	service.forkChoiceStore = protoarray.New(0, 0, [32]byte{'A'})
+	service.cfg.ForkChoiceStore = protoarray.New(0, 0, [32]byte{'A'})
 	service.finalizedCheckpt = &ethpb.Checkpoint{Root: make([]byte, 32)}

 	genesisStateRoot := [32]byte{}
@@ -360,7 +361,7 @@ func TestFillForkChoiceMissingBlocks_CanSave(t *testing.T) {
 	st, err := testutil.NewBeaconState()
 	require.NoError(t, err)

-	require.NoError(t, service.beaconDB.SaveState(ctx, st.Copy(), validGenesisRoot))
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, st.Copy(), validGenesisRoot))
 	roots, err := blockTree1(t, beaconDB, validGenesisRoot[:])
 	require.NoError(t, err)

@@ -374,10 +375,10 @@ func TestFillForkChoiceMissingBlocks_CanSave(t *testing.T) {
 	require.NoError(t, err)

 	// 5 nodes from the block tree 1. B0 - B3 - B4 - B6 - B8
-	assert.Equal(t, 5, len(service.forkChoiceStore.Nodes()), "Miss match nodes")
-	assert.Equal(t, true, service.forkChoiceStore.HasNode(bytesutil.ToBytes32(roots[4])), "Didn't save node")
-	assert.Equal(t, true, service.forkChoiceStore.HasNode(bytesutil.ToBytes32(roots[6])), "Didn't save node")
-	assert.Equal(t, true, service.forkChoiceStore.HasNode(bytesutil.ToBytes32(roots[8])), "Didn't save node")
+	assert.Equal(t, 5, len(service.cfg.ForkChoiceStore.Nodes()), "Miss match nodes")
+	assert.Equal(t, true, service.cfg.ForkChoiceStore.HasNode(bytesutil.ToBytes32(roots[4])), "Didn't save node")
+	assert.Equal(t, true, service.cfg.ForkChoiceStore.HasNode(bytesutil.ToBytes32(roots[6])), "Didn't save node")
+	assert.Equal(t, true, service.cfg.ForkChoiceStore.HasNode(bytesutil.ToBytes32(roots[8])), "Didn't save node")
 }

 func TestFillForkChoiceMissingBlocks_RootsMatch(t *testing.T) {
@@ -387,7 +388,7 @@ func TestFillForkChoiceMissingBlocks_RootsMatch(t *testing.T) {
 	cfg := &Config{BeaconDB: beaconDB}
 	service, err := NewService(ctx, cfg)
 	require.NoError(t, err)
-	service.forkChoiceStore = protoarray.New(0, 0, [32]byte{'A'})
+	service.cfg.ForkChoiceStore = protoarray.New(0, 0, [32]byte{'A'})
 	service.finalizedCheckpt = &ethpb.Checkpoint{Root: make([]byte, 32)}

 	genesisStateRoot := [32]byte{}
@@ -398,7 +399,7 @@ func TestFillForkChoiceMissingBlocks_RootsMatch(t *testing.T) {
 	st, err := testutil.NewBeaconState()
 	require.NoError(t, err)

-	require.NoError(t, service.beaconDB.SaveState(ctx, st.Copy(), validGenesisRoot))
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, st.Copy(), validGenesisRoot))
 	roots, err := blockTree1(t, beaconDB, validGenesisRoot[:])
 	require.NoError(t, err)

@@ -412,12 +413,12 @@ func TestFillForkChoiceMissingBlocks_RootsMatch(t *testing.T) {
 	require.NoError(t, err)

 	// 5 nodes from the block tree 1. B0 - B3 - B4 - B6 - B8
-	assert.Equal(t, 5, len(service.forkChoiceStore.Nodes()), "Miss match nodes")
+	assert.Equal(t, 5, len(service.cfg.ForkChoiceStore.Nodes()), "Miss match nodes")
 	// Ensure all roots and their respective blocks exist.
 	wantedRoots := [][]byte{roots[0], roots[3], roots[4], roots[6], roots[8]}
 	for i, rt := range wantedRoots {
-		assert.Equal(t, true, service.forkChoiceStore.HasNode(bytesutil.ToBytes32(rt)), fmt.Sprintf("Didn't save node: %d", i))
-		assert.Equal(t, true, service.beaconDB.HasBlock(context.Background(), bytesutil.ToBytes32(rt)))
+		assert.Equal(t, true, service.cfg.ForkChoiceStore.HasNode(bytesutil.ToBytes32(rt)), fmt.Sprintf("Didn't save node: %d", i))
+		assert.Equal(t, true, service.cfg.BeaconDB.HasBlock(context.Background(), bytesutil.ToBytes32(rt)))
 	}
 }

@@ -428,7 +429,7 @@ func TestFillForkChoiceMissingBlocks_FilterFinalized(t *testing.T) {
 	cfg := &Config{BeaconDB: beaconDB}
 	service, err := NewService(ctx, cfg)
 	require.NoError(t, err)
-	service.forkChoiceStore = protoarray.New(0, 0, [32]byte{'A'})
+	service.cfg.ForkChoiceStore = protoarray.New(0, 0, [32]byte{'A'})
 	// Set finalized epoch to 1.
 	service.finalizedCheckpt = &ethpb.Checkpoint{Epoch: 1}

@@ -440,24 +441,24 @@ func TestFillForkChoiceMissingBlocks_FilterFinalized(t *testing.T) {
 	st, err := testutil.NewBeaconState()
 	require.NoError(t, err)

-	require.NoError(t, service.beaconDB.SaveState(ctx, st.Copy(), validGenesisRoot))
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, st.Copy(), validGenesisRoot))

 	// Define a tree branch, slot 63 <- 64 <- 65
 	b63 := testutil.NewBeaconBlock()
 	b63.Block.Slot = 63
-	require.NoError(t, service.beaconDB.SaveBlock(ctx, b63))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, b63))
 	r63, err := b63.Block.HashTreeRoot()
 	require.NoError(t, err)
 	b64 := testutil.NewBeaconBlock()
 	b64.Block.Slot = 64
 	b64.Block.ParentRoot = r63[:]
-	require.NoError(t, service.beaconDB.SaveBlock(ctx, b64))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, b64))
 	r64, err := b64.Block.HashTreeRoot()
 	require.NoError(t, err)
 	b65 := testutil.NewBeaconBlock()
 	b65.Block.Slot = 65
 	b65.Block.ParentRoot = r64[:]
-	require.NoError(t, service.beaconDB.SaveBlock(ctx, b65))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, b65))

 	beaconState, _ := testutil.DeterministicGenesisState(t, 32)
 	err = service.fillInForkChoiceMissingBlocks(
@@ -465,10 +466,10 @@ func TestFillForkChoiceMissingBlocks_FilterFinalized(t *testing.T) {
 	require.NoError(t, err)

 	// There should be 2 nodes, block 65 and block 64.
-	assert.Equal(t, 2, len(service.forkChoiceStore.Nodes()), "Miss match nodes")
+	assert.Equal(t, 2, len(service.cfg.ForkChoiceStore.Nodes()), "Miss match nodes")

 	// Block with slot 63 should be in fork choice because it's less than finalized epoch 1.
-	assert.Equal(t, true, service.forkChoiceStore.HasNode(r63), "Didn't save node")
+	assert.Equal(t, true, service.cfg.ForkChoiceStore.HasNode(r63), "Didn't save node")
 }

 // blockTree1 constructs the following tree:
@@ -648,7 +649,7 @@ func TestAncestor_CanUseForkchoice(t *testing.T) {
 		beaconBlock.Block.ParentRoot = bytesutil.PadTo(b.Block.ParentRoot, 32)
 		r, err := b.Block.HashTreeRoot()
 		require.NoError(t, err)
-		require.NoError(t, service.forkChoiceStore.ProcessBlock(context.Background(), b.Block.Slot, r, bytesutil.ToBytes32(b.Block.ParentRoot), [32]byte{}, 0, 0)) // Saves blocks to fork choice store.
+		require.NoError(t, service.cfg.ForkChoiceStore.ProcessBlock(context.Background(), b.Block.Slot, r, bytesutil.ToBytes32(b.Block.ParentRoot), [32]byte{}, 0, 0)) // Saves blocks to fork choice store.
 	}

 	r, err := service.ancestor(context.Background(), r200[:], 150)
@@ -688,7 +689,7 @@ func TestAncestor_CanUseDB(t *testing.T) {
 		require.NoError(t, beaconDB.SaveBlock(context.Background(), beaconBlock)) // Saves blocks to DB.
 	}

-	require.NoError(t, service.forkChoiceStore.ProcessBlock(context.Background(), 200, r200, r200, [32]byte{}, 0, 0))
+	require.NoError(t, service.cfg.ForkChoiceStore.ProcessBlock(context.Background(), 200, r200, r200, [32]byte{}, 0, 0))

 	r, err := service.ancestor(context.Background(), r200[:], 150)
 	require.NoError(t, err)
@@ -757,10 +758,10 @@ func TestFinalizedImpliesNewJustified(t *testing.T) {
 		service, err := NewService(ctx, &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB), ForkChoiceStore: protoarray.New(0, 0, [32]byte{})})
 		require.NoError(t, err)
 		service.justifiedCheckpt = test.args.cachedCheckPoint
-		require.NoError(t, service.beaconDB.SaveStateSummary(ctx, &pb.StateSummary{Root: bytesutil.PadTo(test.want.Root, 32)}))
+		require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(ctx, &pb.StateSummary{Root: bytesutil.PadTo(test.want.Root, 32)}))
 		genesisState, err := testutil.NewBeaconState()
 		require.NoError(t, err)
-		require.NoError(t, service.beaconDB.SaveState(ctx, genesisState, bytesutil.ToBytes32(test.want.Root)))
+		require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, genesisState, bytesutil.ToBytes32(test.want.Root)))

 		if test.args.diffFinalizedCheckPoint {
 			b1 := testutil.NewBeaconBlock()
@@ -777,7 +778,7 @@ func TestFinalizedImpliesNewJustified(t *testing.T) {
 				beaconBlock := testutil.NewBeaconBlock()
 				beaconBlock.Block.Slot = b.Block.Slot
 				beaconBlock.Block.ParentRoot = bytesutil.PadTo(b.Block.ParentRoot, 32)
-				require.NoError(t, service.beaconDB.SaveBlock(context.Background(), beaconBlock))
+				require.NoError(t, service.cfg.BeaconDB.SaveBlock(context.Background(), beaconBlock))
 			}
 			service.finalizedCheckpt = &ethpb.Checkpoint{Root: []byte{'c'}, Epoch: 1}
 			service.justifiedCheckpt.Root = r100[:]
@@ -870,11 +871,11 @@ func TestUpdateJustifiedInitSync(t *testing.T) {
 	gBlk := testutil.NewBeaconBlock()
 	gRoot, err := gBlk.Block.HashTreeRoot()
 	require.NoError(t, err)
-	require.NoError(t, service.beaconDB.SaveBlock(ctx, gBlk))
-	require.NoError(t, service.beaconDB.SaveGenesisBlockRoot(ctx, gRoot))
-	require.NoError(t, service.beaconDB.SaveStateSummary(ctx, &pb.StateSummary{Root: gRoot[:]}))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, gBlk))
+	require.NoError(t, service.cfg.BeaconDB.SaveGenesisBlockRoot(ctx, gRoot))
+	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(ctx, &pb.StateSummary{Root: gRoot[:]}))
 	beaconState, _ := testutil.DeterministicGenesisState(t, 32)
-	require.NoError(t, service.beaconDB.SaveState(ctx, beaconState, gRoot))
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, beaconState, gRoot))
 	service.genesisRoot = gRoot
 	currentCp := &ethpb.Checkpoint{Epoch: 1}
 	service.justifiedCheckpt = currentCp
@@ -884,7 +885,7 @@ func TestUpdateJustifiedInitSync(t *testing.T) {

 	assert.DeepSSZEqual(t, currentCp, service.prevJustifiedCheckpt, "Incorrect previous justified checkpoint")
 	assert.DeepSSZEqual(t, newCp, service.CurrentJustifiedCheckpt(), "Incorrect current justified checkpoint in cache")
-	cp, err := service.beaconDB.JustifiedCheckpoint(ctx)
+	cp, err := service.cfg.BeaconDB.JustifiedCheckpoint(ctx)
 	require.NoError(t, err)
 	assert.DeepSSZEqual(t, newCp, cp, "Incorrect current justified checkpoint in db")
 }
@@ -898,7 +899,8 @@ func TestHandleEpochBoundary_BadMetrics(t *testing.T) {
 	s, err := testutil.NewBeaconState()
 	require.NoError(t, err)
 	require.NoError(t, s.SetSlot(1))
-	service.head = &head{}
+	service.head = &head{state: (*stateV0.BeaconState)(nil)}
+
 	require.ErrorContains(t, "failed to initialize precompute: nil inner state", service.handleEpochBoundary(ctx, s))
 }

@@ -931,7 +933,7 @@ func TestOnBlock_CanFinalize(t *testing.T) {

 	gs, keys := testutil.DeterministicGenesisState(t, 32)
 	require.NoError(t, service.saveGenesisData(ctx, gs))
-	gBlk, err := service.beaconDB.GenesisBlock(ctx)
+	gBlk, err := service.cfg.BeaconDB.GenesisBlock(ctx)
 	require.NoError(t, err)
 	gRoot, err := gBlk.Block.HashTreeRoot()
 	require.NoError(t, err)
@@ -944,7 +946,7 @@ func TestOnBlock_CanFinalize(t *testing.T) {
 		r, err := blk.Block.HashTreeRoot()
 		require.NoError(t, err)
 		require.NoError(t, service.onBlock(ctx, blk, r))
-		testState, err = service.stateGen.StateByRoot(ctx, r)
+		testState, err = service.cfg.StateGen.StateByRoot(ctx, r)
 		require.NoError(t, err)
 	}
 	require.Equal(t, types.Epoch(3), service.CurrentJustifiedCheckpt().Epoch)
@@ -967,23 +969,23 @@ func TestInsertFinalizedDeposits(t *testing.T) {

 	gs, _ := testutil.DeterministicGenesisState(t, 32)
 	require.NoError(t, service.saveGenesisData(ctx, gs))
-	gBlk, err := service.beaconDB.GenesisBlock(ctx)
+	gBlk, err := service.cfg.BeaconDB.GenesisBlock(ctx)
 	require.NoError(t, err)
 	gRoot, err := gBlk.Block.HashTreeRoot()
 	require.NoError(t, err)
 	service.finalizedCheckpt = &ethpb.Checkpoint{Root: gRoot[:]}
 	gs = gs.Copy()
 	assert.NoError(t, gs.SetEth1Data(&ethpb.Eth1Data{DepositCount: 10}))
-	assert.NoError(t, service.stateGen.SaveState(ctx, [32]byte{'m', 'o', 'c', 'k'}, gs))
+	assert.NoError(t, service.cfg.StateGen.SaveState(ctx, [32]byte{'m', 'o', 'c', 'k'}, gs))
 	zeroSig := [96]byte{}
 	for i := uint64(0); i < uint64(4*params.BeaconConfig().SlotsPerEpoch); i++ {
 		root := []byte(strconv.Itoa(int(i)))
-		depositCache.InsertDeposit(ctx, &ethpb.Deposit{Data: &ethpb.Deposit_Data{
+		assert.NoError(t, depositCache.InsertDeposit(ctx, &ethpb.Deposit{Data: &ethpb.Deposit_Data{
 			PublicKey:             bytesutil.FromBytes48([48]byte{}),
 			WithdrawalCredentials: params.BeaconConfig().ZeroHash[:],
 			Amount:                0,
 			Signature:             zeroSig[:],
-		}, Proof: [][]byte{root}}, 100+i, int64(i), bytesutil.ToBytes32(root))
+		}, Proof: [][]byte{root}}, 100+i, int64(i), bytesutil.ToBytes32(root)))
 	}
 	assert.NoError(t, service.insertFinalizedDeposits(ctx, [32]byte{'m', 'o', 'c', 'k'}))
 	fDeposits := depositCache.FinalizedDeposits(ctx)
--- a/beacon-chain/blockchain/receive_attestation.go
+++ b/beacon-chain/blockchain/receive_attestation.go
@@ -10,7 +10,7 @@ import (
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"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/params"
 	"github.com/prysmaticlabs/prysm/shared/slotutil"
@@ -21,7 +21,7 @@ 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
-	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
 }
@@ -43,7 +43,7 @@ func (s *Service) ReceiveAttestationNoPubsub(ctx context.Context, att *ethpb.Att
 }

 // 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
@@ -76,7 +76,7 @@ func (s *Service) VerifyLmdFfgConsistency(ctx context.Context, a *ethpb.Attestat
 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.forkChoiceStore.IsCanonical(bytesutil.ToBytes32(root)) {
+	if s.cfg.ForkChoiceStore.IsCanonical(bytesutil.ToBytes32(root)) {
 		return nil
 	}

@@ -100,7 +100,7 @@ func (s *Service) VerifyFinalizedConsistency(ctx context.Context, root []byte) e
 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()
@@ -121,7 +121,7 @@ func (s *Service) processAttestationsRoutine(subscribedToStateEvents chan<- stru
 		case <-st.C():
 			// 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.attPool.ForkchoiceAttestationCount() == 0 {
+			if s.cfg.AttPool.ForkchoiceAttestationCount() == 0 {
 				continue
 			}
 			s.processAttestations(s.ctx)
@@ -134,7 +134,7 @@ func (s *Service) processAttestationsRoutine(subscribedToStateEvents chan<- stru

 // 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.attPool.ForkchoiceAttestations()
+	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.
@@ -144,13 +144,13 @@ func (s *Service) processAttestations(ctx context.Context) {
 			continue
 		}

-		hasState := s.beaconDB.HasStateSummary(ctx, bytesutil.ToBytes32(a.Data.BeaconBlockRoot))
+		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.attPool.DeleteForkchoiceAttestation(a); err != nil {
+		if err := s.cfg.AttPool.DeleteForkchoiceAttestation(a); err != nil {
 			log.WithError(err).Error("Could not delete fork choice attestation in pool")
 		}

--- a/beacon-chain/blockchain/receive_attestation_test.go
+++ b/beacon-chain/blockchain/receive_attestation_test.go
@@ -43,13 +43,13 @@ func TestVerifyLMDFFGConsistent_NotOK(t *testing.T) {

 	b32 := testutil.NewBeaconBlock()
 	b32.Block.Slot = 32
-	require.NoError(t, service.beaconDB.SaveBlock(ctx, b32))
+	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.beaconDB.SaveBlock(ctx, b33))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, b33))
 	r33, err := b33.Block.HashTreeRoot()
 	require.NoError(t, err)

@@ -71,13 +71,13 @@ func TestVerifyLMDFFGConsistent_OK(t *testing.T) {

 	b32 := testutil.NewBeaconBlock()
 	b32.Block.Slot = 32
-	require.NoError(t, service.beaconDB.SaveBlock(ctx, b32))
+	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.beaconDB.SaveBlock(ctx, b33))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, b33))
 	r33, err := b33.Block.HashTreeRoot()
 	require.NoError(t, err)

@@ -112,10 +112,10 @@ func TestProcessAttestations_Ok(t *testing.T) {
 	copied := genesisState.Copy()
 	copied, err = state.ProcessSlots(ctx, copied, 1)
 	require.NoError(t, err)
-	require.NoError(t, service.beaconDB.SaveState(ctx, copied, tRoot))
-	require.NoError(t, service.forkChoiceStore.ProcessBlock(ctx, 0, tRoot, tRoot, tRoot, 1, 1))
-	require.NoError(t, service.attPool.SaveForkchoiceAttestations(atts))
+	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.attPool.ForkchoiceAttestations()))
+	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
@@ -9,7 +9,7 @@ import (
 	"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"
@@ -35,7 +35,7 @@ func (s *Service) ReceiveBlock(ctx context.Context, block *ethpb.SignedBeaconBlo
 	ctx, span := trace.StartSpan(ctx, "blockChain.ReceiveBlock")
 	defer span.End()
 	receivedTime := timeutils.Now()
-	blockCopy := stateTrie.CopySignedBeaconBlock(block)
+	blockCopy := stateV0.CopySignedBeaconBlock(block)

 	// Apply state transition on the new block.
 	if err := s.onBlock(ctx, blockCopy, blockRoot); err != nil {
@@ -50,7 +50,7 @@ func (s *Service) ReceiveBlock(ctx context.Context, block *ethpb.SignedBeaconBlo
 			log.WithError(err).Warn("Could not update head")
 		}
 		// Send notification of the processed block to the state feed.
-		s.stateNotifier.StateFeed().Send(&feed.Event{
+		s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
 			Type: statefeed.BlockProcessed,
 			Data: &statefeed.BlockProcessedData{
 				Slot:        blockCopy.Block.Slot,
@@ -100,13 +100,13 @@ func (s *Service) ReceiveBlockBatch(ctx context.Context, blocks []*ethpb.SignedB
 	}

 	for i, b := range blocks {
-		blockCopy := stateTrie.CopySignedBeaconBlock(b)
+		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.stateNotifier.StateFeed().Send(&feed.Event{
+		s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
 			Type: statefeed.BlockProcessed,
 			Data: &statefeed.BlockProcessedData{
 				Slot:        blockCopy.Block.Slot,
@@ -142,18 +142,18 @@ func (s *Service) handlePostBlockOperations(b *ethpb.BeaconBlock) error {
 	}

 	// Add block attestations to the fork choice pool to compute head.
-	if err := s.attPool.SaveBlockAttestations(b.Body.Attestations); err != nil {
+	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.exitPool.MarkIncluded(e)
+		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.slashingPool.MarkIncludedAttesterSlashing(as)
+		s.cfg.SlashingPool.MarkIncludedAttesterSlashing(as)
 	}
 	return nil
 }
@@ -169,9 +169,9 @@ func (s *Service) checkSaveHotStateDB(ctx context.Context) error {
 	}

 	if sinceFinality >= epochsSinceFinalitySaveHotStateDB {
-		s.stateGen.EnableSaveHotStateToDB(ctx)
+		s.cfg.StateGen.EnableSaveHotStateToDB(ctx)
 		return nil
 	}

-	return s.stateGen.DisableSaveHotStateToDB(ctx)
+	return s.cfg.StateGen.DisableSaveHotStateToDB(ctx)
 }
--- a/beacon-chain/blockchain/receive_block_test.go
+++ b/beacon-chain/blockchain/receive_block_test.go
@@ -73,7 +73,7 @@ func TestService_ReceiveBlock(t *testing.T) {
 				),
 			},
 			check: func(t *testing.T, s *Service) {
-				if baCount := len(s.attPool.BlockAttestations()); baCount != 2 {
+				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)
 				}
@@ -93,7 +93,7 @@ func TestService_ReceiveBlock(t *testing.T) {
 				),
 			},
 			check: func(t *testing.T, s *Service) {
-				pending := s.exitPool.PendingExits(genesis, 1, true /* no limit */)
+				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",
@@ -109,7 +109,7 @@ func TestService_ReceiveBlock(t *testing.T) {
 				block: genFullBlock(t, testutil.DefaultBlockGenConfig(), 1 /*slot*/),
 			},
 			check: func(t *testing.T, s *Service) {
-				if recvd := len(s.stateNotifier.(*blockchainTesting.MockStateNotifier).ReceivedEvents()); recvd < 1 {
+				if recvd := len(s.cfg.StateNotifier.(*blockchainTesting.MockStateNotifier).ReceivedEvents()); recvd < 1 {
 					t.Errorf("Received %d state notifications, expected at least 1", recvd)
 				}
 			},
@@ -137,7 +137,7 @@ func TestService_ReceiveBlock(t *testing.T) {
 			s, err := NewService(ctx, cfg)
 			require.NoError(t, err)
 			require.NoError(t, s.saveGenesisData(ctx, genesis))
-			gBlk, err := s.beaconDB.GenesisBlock(ctx)
+			gBlk, err := s.cfg.BeaconDB.GenesisBlock(ctx)
 			require.NoError(t, err)
 			gRoot, err := gBlk.Block.HashTreeRoot()
 			require.NoError(t, err)
@@ -178,7 +178,7 @@ func TestService_ReceiveBlockUpdateHead(t *testing.T) {
 	s, err := NewService(ctx, cfg)
 	require.NoError(t, err)
 	require.NoError(t, s.saveGenesisData(ctx, genesis))
-	gBlk, err := s.beaconDB.GenesisBlock(ctx)
+	gBlk, err := s.cfg.BeaconDB.GenesisBlock(ctx)
 	require.NoError(t, err)
 	gRoot, err := gBlk.Block.HashTreeRoot()
 	require.NoError(t, err)
@@ -192,11 +192,11 @@ func TestService_ReceiveBlockUpdateHead(t *testing.T) {
 		wg.Done()
 	}()
 	wg.Wait()
-	if recvd := len(s.stateNotifier.(*blockchainTesting.MockStateNotifier).ReceivedEvents()); recvd < 1 {
+	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.forkChoiceStore.Nodes()))
+	assert.Equal(t, 2, len(s.cfg.ForkChoiceStore.Nodes()))
 }

 func TestService_ReceiveBlockBatch(t *testing.T) {
@@ -234,7 +234,7 @@ func TestService_ReceiveBlockBatch(t *testing.T) {
 				block: genFullBlock(t, testutil.DefaultBlockGenConfig(), 1 /*slot*/),
 			},
 			check: func(t *testing.T, s *Service) {
-				if recvd := len(s.stateNotifier.(*blockchainTesting.MockStateNotifier).ReceivedEvents()); recvd < 1 {
+				if recvd := len(s.cfg.StateNotifier.(*blockchainTesting.MockStateNotifier).ReceivedEvents()); recvd < 1 {
 					t.Errorf("Received %d state notifications, expected at least 1", recvd)
 				}
 			},
@@ -260,7 +260,7 @@ func TestService_ReceiveBlockBatch(t *testing.T) {
 			require.NoError(t, err)
 			err = s.saveGenesisData(ctx, genesis)
 			require.NoError(t, err)
-			gBlk, err := s.beaconDB.GenesisBlock(ctx)
+			gBlk, err := s.cfg.BeaconDB.GenesisBlock(ctx)
 			require.NoError(t, err)

 			gRoot, err := gBlk.Block.HashTreeRoot()
--- a/beacon-chain/blockchain/service.go
+++ b/beacon-chain/blockchain/service.go
@@ -15,7 +15,6 @@ import (
 	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/feed"
 	statefeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
@@ -28,10 +27,10 @@ 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/cmd/beacon-chain/flags"
-	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/slotutil"
@@ -46,22 +45,13 @@ const headSyncMinEpochsAfterCheckpoint = 128
 // Service represents a service that handles the internal
 // logic of managing the full PoS beacon chain.
 type Service struct {
+	cfg                   *Config
 	ctx                   context.Context
 	cancel                context.CancelFunc
-	beaconDB              db.HeadAccessDatabase
-	depositCache          *depositcache.DepositCache
-	chainStartFetcher     powchain.ChainStartFetcher
-	attPool               attestations.Pool
-	slashingPool          slashings.PoolManager
-	exitPool              voluntaryexits.PoolManager
 	genesisTime           time.Time
-	p2p                   p2p.Broadcaster
-	maxRoutines           int
 	head                  *head
 	headLock              sync.RWMutex
-	stateNotifier         statefeed.Notifier
 	genesisRoot           [32]byte
-	forkChoiceStore       f.ForkChoicer
 	justifiedCheckpt      *ethpb.Checkpoint
 	prevJustifiedCheckpt  *ethpb.Checkpoint
 	bestJustifiedCheckpt  *ethpb.Checkpoint
@@ -70,34 +60,29 @@ type Service struct {
 	nextEpochBoundarySlot types.Slot
 	boundaryRoots         [][32]byte
 	checkpointStateCache  *cache.CheckpointStateCache
-	stateGen              *stategen.State
-	opsService            *attestations.Service
 	initSyncBlocks        map[[32]byte]*ethpb.SignedBeaconBlock
 	initSyncBlocksLock    sync.RWMutex
 	justifiedBalances     []uint64
 	justifiedBalancesLock sync.RWMutex
-	wsEpoch               types.Epoch
-	wsRoot                []byte
 	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.PoolManager
-	SlashingPool      slashings.PoolManager
-	P2p               p2p.Broadcaster
-	MaxRoutines       int
-	StateNotifier     statefeed.Notifier
-	ForkChoiceStore   f.ForkChoicer
-	OpsService        *attestations.Service
-	StateGen          *stategen.State
-	WspBlockRoot      []byte
-	WspEpoch          types.Epoch
+	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
@@ -105,26 +90,13 @@ type Config struct {
 func NewService(ctx context.Context, cfg *Config) (*Service, error) {
 	ctx, cancel := context.WithCancel(ctx)
 	return &Service{
+		cfg:                  cfg,
 		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,
-		forkChoiceStore:      cfg.ForkChoiceStore,
 		boundaryRoots:        [][32]byte{},
 		checkpointStateCache: cache.NewCheckpointStateCache(),
-		opsService:           cfg.OpsService,
-		stateGen:             cfg.StateGen,
 		initSyncBlocks:       make(map[[32]byte]*ethpb.SignedBeaconBlock),
 		justifiedBalances:    make([]uint64, 0),
-		wsEpoch:              cfg.WspEpoch,
-		wsRoot:               cfg.WspBlockRoot,
 	}, nil
 }

@@ -133,7 +105,7 @@ func (s *Service) Start() {
 	// 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(s.ctx)
+	cp, err := s.cfg.BeaconDB.FinalizedCheckpoint(s.ctx)
 	if err != nil {
 		log.Fatalf("Could not fetch finalized cp: %v", err)
 	}
@@ -143,7 +115,7 @@ func (s *Service) Start() {
 	// 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.beaconDB.GenesisBlock(s.ctx)
+		genesisBlock, err := s.cfg.BeaconDB.GenesisBlock(s.ctx)
 		if err != nil {
 			log.Fatalf("Could not fetch finalized cp: %v", err)
 		}
@@ -154,7 +126,7 @@ func (s *Service) Start() {
 			}
 		}
 	}
-	beaconState, err := s.stateGen.StateByRoot(s.ctx, r)
+	beaconState, err := s.cfg.StateGen.StateByRoot(s.ctx, r)
 	if err != nil {
 		log.Fatalf("Could not fetch beacon state by root: %v", err)
 	}
@@ -163,16 +135,16 @@ func (s *Service) Start() {
 	attestationProcessorSubscribed := make(chan struct{}, 1)

 	// If the chain has already been initialized, simply start the block processing routine.
-	if beaconState != nil {
+	if beaconState != nil && !beaconState.IsNil() {
 		log.Info("Blockchain data already exists in DB, initializing...")
 		s.genesisTime = time.Unix(int64(beaconState.GenesisTime()), 0)
-		s.opsService.SetGenesisTime(beaconState.GenesisTime())
+		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.
-		gState, err := s.beaconDB.GenesisState(s.ctx)
+		gState, err := s.cfg.BeaconDB.GenesisState(s.ctx)
 		if err != nil {
 			log.Fatalf("Could not retrieve genesis state: %v", err)
 		}
@@ -182,24 +154,24 @@ func (s *Service) Start() {
 		}
 		go slotutil.CountdownToGenesis(s.ctx, s.genesisTime, uint64(gState.NumValidators()), gRoot)

-		justifiedCheckpoint, err := s.beaconDB.JustifiedCheckpoint(s.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(s.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)
+		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)

 		ss, err := helpers.StartSlot(s.finalizedCheckpt.Epoch)
@@ -222,7 +194,7 @@ func (s *Service) Start() {
 			log.Fatalf("Could not verify weak subjectivity checkpoint: %v", err)
 		}

-		s.stateNotifier.StateFeed().Send(&feed.Event{
+		s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
 			Type: statefeed.Initialized,
 			Data: &statefeed.InitializedData{
 				StartTime:             s.genesisTime,
@@ -231,13 +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 {
@@ -270,8 +242,8 @@ func (s *Service) Start() {
 // 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)
 	}
@@ -284,7 +256,7 @@ func (s *Service) processChainStartTime(ctx context.Context, genesisTime time.Ti

 	// 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,
@@ -299,8 +271,8 @@ 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) {
+	preGenesisState iface.BeaconState,
+	eth1data *ethpb.Eth1Data) (iface.BeaconState, error) {
 	ctx, span := trace.StartSpan(ctx, "beacon-chain.Service.initializeBeaconChain")
 	defer span.End()
 	s.genesisTime = genesisTime
@@ -318,7 +290,7 @@ 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 {
@@ -328,7 +300,7 @@ func (s *Service) initializeBeaconChain(
 		return nil, err
 	}

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

 	return genesisState, nil
 }
@@ -337,14 +309,14 @@ func (s *Service) initializeBeaconChain(
 func (s *Service) Stop() error {
 	defer s.cancel()

-	if s.stateGen != nil && s.head != nil && s.head.state != nil {
-		if err := s.stateGen.ForceCheckpoint(s.ctx, s.head.state.FinalizedCheckpoint().Root); err != 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.beaconDB.SaveBlocks(s.ctx, s.getInitSyncBlocks())
+	return s.cfg.BeaconDB.SaveBlocks(s.ctx, s.getInitSyncBlocks())
 }

 // Status always returns nil unless there is an error condition that causes
@@ -353,60 +325,42 @@ func (s *Service) Status() error {
 	if s.genesisRoot == params.BeaconConfig().ZeroHash {
 		return errors.New("genesis state has not been created")
 	}
-	if runtime.NumGoroutine() > s.maxRoutines {
+	if runtime.NumGoroutine() > s.cfg.MaxRoutines {
 		return fmt.Errorf("too many goroutines %d", runtime.NumGoroutine())
 	}
 	return nil
 }

 // 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, err := s.cfg.BeaconDB.GenesisBlock(ctx)
+	if err != nil || genesisBlk == nil {
+		return fmt.Errorf("could not load genesis block: %v", err)
 	}
-	genesisBlk := blocks.NewGenesisBlock(stateRoot[:])
 	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.beaconDB.SaveState(ctx, genesisState, genesisBlkRoot); 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
-	}
-
-	s.stateGen.SaveFinalizedState(0, genesisBlkRoot, genesisState)
-
-	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,
@@ -417,13 +371,12 @@ 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")
 	}
@@ -436,7 +389,7 @@ func (s *Service) initializeChainInfo(ctx context.Context) error {
 	}
 	s.genesisRoot = genesisBlkRoot

-	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")
 	}
@@ -446,15 +399,15 @@ func (s *Service) initializeChainInfo(ctx context.Context) error {
 		return errors.New("no finalized epoch in the database")
 	}
 	finalizedRoot := s.ensureRootNotZeros(bytesutil.ToBytes32(finalized.Root))
-	var finalizedState *stateTrie.BeaconState
+	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 flags.Get().HeadSync {
-		headBlock, err := s.beaconDB.HeadBlock(ctx)
+		headBlock, err := s.cfg.BeaconDB.HeadBlock(ctx)
 		if err != nil {
 			return errors.Wrap(err, "could not retrieve head block")
 		}
@@ -470,13 +423,13 @@ func (s *Service) initializeChainInfo(ctx context.Context) error {
 			if err != nil {
 				return errors.Wrap(err, "could not hash head block")
 			}
-			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")
 			}
 			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.stateGen.StateByRoot(ctx, headRoot)
+			headState, err := s.cfg.StateGen.StateByRoot(ctx, headRoot)
 			if err != nil {
 				return errors.Wrap(err, "could not retrieve head state")
 			}
@@ -489,7 +442,7 @@ func (s *Service) initializeChainInfo(ctx context.Context) error {
 		}
 	}

-	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")
 	}
@@ -506,7 +459,7 @@ func (s *Service) initializeChainInfo(ctx context.Context) error {
 // information to fork choice service to initializes fork choice store.
 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:
@@ -514,9 +467,9 @@ func (s *Service) resumeForkChoice(justifiedCheckpoint, finalizedCheckpoint *eth
 // 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
@@ -18,7 +18,7 @@ func init() {
 func TestChainService_SaveHead_DataRace(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
 	s := &Service{
-		beaconDB: beaconDB,
+		cfg: &Config{BeaconDB: beaconDB},
 	}
 	go func() {
 		require.NoError(t, s.saveHead(context.Background(), [32]byte{}))
--- a/beacon-chain/blockchain/service_test.go
+++ b/beacon-chain/blockchain/service_test.go
@@ -8,7 +8,6 @@ import (
 	"time"

 	"github.com/ethereum/go-ethereum/common"
-	"github.com/gogo/protobuf/proto"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/cache/depositcache"
 	b "github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
@@ -22,7 +21,7 @@ import (
 	"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/cmd/beacon-chain/flags"
 	protodb "github.com/prysmaticlabs/prysm/proto/beacon/db"
@@ -34,6 +33,7 @@ import (
 	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
 	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 	logTest "github.com/sirupsen/logrus/hooks/test"
+	"google.golang.org/protobuf/proto"
 )

 type mockBeaconNode struct {
@@ -70,8 +70,10 @@ func setupBeaconChain(t *testing.T, beaconDB db.Database) *Service {
 	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),
@@ -88,7 +90,7 @@ func setupBeaconChain(t *testing.T, beaconDB db.Database) *Service {
 	require.NoError(t, err)
 	web3Service, err = powchain.NewService(ctx, &powchain.Web3ServiceConfig{
 		BeaconDB:        beaconDB,
-		HTTPEndpoints:   []string{endpoint},
+		HttpEndpoints:   []string{endpoint},
 		DepositContract: common.Address{},
 	})
 	require.NoError(t, err, "Unable to set up web3 service")
@@ -274,7 +276,7 @@ func TestChainService_InitializeChainInfo(t *testing.T) {
 	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{beaconDB: beaconDB, stateGen: stategen.New(beaconDB)}
+	c := &Service{cfg: &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)}}
 	require.NoError(t, c.initializeChainInfo(ctx))
 	headBlk, err := c.HeadBlock(ctx)
 	require.NoError(t, err)
@@ -314,7 +316,7 @@ func TestChainService_InitializeChainInfo_SetHeadAtGenesis(t *testing.T) {
 	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{beaconDB: beaconDB, stateGen: stategen.New(beaconDB)}
+	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)
@@ -371,7 +373,7 @@ func TestChainService_InitializeChainInfo_HeadSync(t *testing.T) {
 		Root:  finalizedRoot[:],
 	}))

-	c := &Service{beaconDB: beaconDB, stateGen: stategen.New(beaconDB)}
+	c := &Service{cfg: &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)}}

 	require.NoError(t, c.initializeChainInfo(ctx))
 	s, err := c.HeadState(ctx)
@@ -409,8 +411,7 @@ func TestChainService_SaveHeadNoDB(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
 	ctx := context.Background()
 	s := &Service{
-		beaconDB: beaconDB,
-		stateGen: stategen.New(beaconDB),
+		cfg: &Config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)},
 	}
 	blk := testutil.NewBeaconBlock()
 	blk.Block.Slot = 1
@@ -418,10 +419,10 @@ func TestChainService_SaveHeadNoDB(t *testing.T) {
 	require.NoError(t, err)
 	newState, err := testutil.NewBeaconState()
 	require.NoError(t, err)
-	require.NoError(t, s.stateGen.SaveState(ctx, r, newState))
+	require.NoError(t, s.cfg.StateGen.SaveState(ctx, r, newState))
 	require.NoError(t, s.saveHeadNoDB(ctx, blk, r, newState))

-	newB, err := s.beaconDB.HeadBlock(ctx)
+	newB, err := s.cfg.BeaconDB.HeadBlock(ctx)
 	require.NoError(t, err)
 	if reflect.DeepEqual(newB, blk) {
 		t.Error("head block should not be equal")
@@ -432,9 +433,8 @@ func TestHasBlock_ForkChoiceAndDB(t *testing.T) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(t)
 	s := &Service{
-		forkChoiceStore:  protoarray.New(0, 0, [32]byte{}),
+		cfg:              &Config{ForkChoiceStore: protoarray.New(0, 0, [32]byte{}), BeaconDB: beaconDB},
 		finalizedCheckpt: &ethpb.Checkpoint{Root: make([]byte, 32)},
-		beaconDB:         beaconDB,
 	}
 	block := testutil.NewBeaconBlock()
 	r, err := block.Block.HashTreeRoot()
@@ -451,25 +451,24 @@ 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,
-		beaconDB:       beaconDB,
 		initSyncBlocks: make(map[[32]byte]*ethpb.SignedBeaconBlock),
-		stateGen:       stategen.New(beaconDB),
 	}
 	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.beaconDB.HasBlock(ctx, r))
+	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.stateNotifier.StateFeed().Subscribe(stateChannel)
+	stateSub := service.cfg.StateNotifier.StateFeed().Subscribe(stateChannel)
 	defer stateSub.Unsubscribe()
 	service.processChainStartTime(context.Background(), time.Now())

@@ -483,16 +482,16 @@ func BenchmarkHasBlockDB(b *testing.B) {
 	beaconDB := testDB.SetupDB(b)
 	ctx := context.Background()
 	s := &Service{
-		beaconDB: beaconDB,
+		cfg: &Config{BeaconDB: beaconDB},
 	}
 	block := testutil.NewBeaconBlock()
-	require.NoError(b, s.beaconDB.SaveBlock(ctx, block))
+	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++ {
-		require.Equal(b, true, s.beaconDB.HasBlock(ctx, r), "Block is not in DB")
+		require.Equal(b, true, s.cfg.BeaconDB.HasBlock(ctx, r), "Block is not in DB")
 	}
 }

@@ -500,20 +499,19 @@ func BenchmarkHasBlockForkChoiceStore(b *testing.B) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(b)
 	s := &Service{
-		forkChoiceStore:  protoarray.New(0, 0, [32]byte{}),
+		cfg:              &Config{ForkChoiceStore: protoarray.New(0, 0, [32]byte{}), BeaconDB: beaconDB},
 		finalizedCheckpt: &ethpb.Checkpoint{Root: make([]byte, 32)},
-		beaconDB:         beaconDB,
 	}
 	block := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{}}}
 	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 := beaconstate.InitializeFromProto(bs)
+	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++ {
-		require.Equal(b, true, s.forkChoiceStore.HasNode(r), "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
@@ -18,8 +18,10 @@ go_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/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",
--- a/beacon-chain/blockchain/testing/mock.go
+++ b/beacon-chain/blockchain/testing/mock.go
@@ -19,8 +19,10 @@ import (
 	"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"
+	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"
@@ -28,7 +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
@@ -149,7 +151,7 @@ func (mon *MockOperationNotifier) OperationFeed() *event.Feed {
 // ReceiveBlockInitialSync mocks ReceiveBlockInitialSync method in chain service.
 func (s *ChainService) ReceiveBlockInitialSync(ctx context.Context, block *ethpb.SignedBeaconBlock, _ [32]byte) error {
 	if s.State == nil {
-		s.State = &stateTrie.BeaconState{}
+		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)
@@ -176,7 +178,7 @@ func (s *ChainService) ReceiveBlockInitialSync(ctx context.Context, block *ethpb
 // 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 = &stateTrie.BeaconState{}
+		s.State = &stateV0.BeaconState{}
 	}
 	for _, block := range blks {
 		if !bytes.Equal(s.Root, block.Block.ParentRoot) {
@@ -205,7 +207,7 @@ func (s *ChainService) ReceiveBlockBatch(ctx context.Context, blks []*ethpb.Sign
 // 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 = &stateTrie.BeaconState{}
+		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)
@@ -251,7 +253,7 @@ func (s *ChainService) HeadBlock(context.Context) (*ethpb.SignedBeaconBlock, err
 }

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

@@ -286,7 +288,7 @@ func (s *ChainService) ReceiveAttestationNoPubsub(context.Context, *ethpb.Attest
 }

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

@@ -381,3 +383,12 @@ func (s *ChainService) VerifyFinalizedConsistency(_ context.Context, r []byte) e
 	}
 	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
@@ -14,7 +14,7 @@ import (
 // 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 len(s.wsRoot) == 0 || s.wsEpoch == 0 {
+	if s.cfg.WeakSubjectivityCheckpt == nil || len(s.cfg.WeakSubjectivityCheckpt.Root) == 0 || s.cfg.WeakSubjectivityCheckpt.Epoch == 0 {
 		return nil
 	}

@@ -23,28 +23,28 @@ func (s *Service) VerifyWeakSubjectivityRoot(ctx context.Context) error {
 	if s.wsVerified {
 		return nil
 	}
-	if s.wsEpoch > s.finalizedCheckpt.Epoch {
+	if s.cfg.WeakSubjectivityCheckpt.Epoch > s.finalizedCheckpt.Epoch {
 		return nil
 	}

-	r := bytesutil.ToBytes32(s.wsRoot)
-	log.Infof("Performing weak subjectivity check for root %#x in epoch %d", r, s.wsEpoch)
+	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.beaconDB.SaveBlocks(ctx, s.getInitSyncBlocks()); err != nil {
+	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.beaconDB.HasBlock(ctx, r) {
+	if !s.cfg.BeaconDB.HasBlock(ctx, r) {
 		return fmt.Errorf("node does not have root in DB: %#x", r)
 	}

-	startSlot, err := helpers.StartSlot(s.wsEpoch)
+	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.beaconDB.BlockRoots(ctx, filter)
+	roots, err := s.cfg.BeaconDB.BlockRoots(ctx, filter)
 	if err != nil {
 		return err
 	}
@@ -56,5 +56,5 @@ func (s *Service) VerifyWeakSubjectivityRoot(ctx context.Context) error {
 		}
 	}

-	return fmt.Errorf("node does not have root in db corresponding to epoch: %#x %d", r, s.wsEpoch)
+	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
@@ -7,6 +7,7 @@ import (
 	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"
 )
@@ -22,8 +23,7 @@ func TestService_VerifyWeakSubjectivityRoot(t *testing.T) {
 	tests := []struct {
 		wsVerified     bool
 		wantErr        bool
-		wsRoot         [32]byte
-		wsEpoch        types.Epoch
+		checkpt        *ethpb.Checkpoint
 		finalizedEpoch types.Epoch
 		errString      string
 		name           string
@@ -34,37 +34,34 @@ func TestService_VerifyWeakSubjectivityRoot(t *testing.T) {
 		},
 		{
 			name:           "already verified",
-			wsEpoch:        2,
+			checkpt:        &ethpb.Checkpoint{Epoch: 2},
 			finalizedEpoch: 2,
 			wsVerified:     true,
 			wantErr:        false,
 		},
 		{
 			name:           "not yet to verify, ws epoch higher than finalized epoch",
-			wsEpoch:        2,
+			checkpt:        &ethpb.Checkpoint{Epoch: 2},
 			finalizedEpoch: 1,
 			wantErr:        false,
 		},
 		{
 			name:           "can't find the block in DB",
-			wsEpoch:        1,
-			wsRoot:         [32]byte{'a'},
+			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",
-			wsEpoch:        2,
-			wsRoot:         r, // Root belongs in epoch 1.
+			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",
-			wsEpoch:        1,
-			wsRoot:         r,
+			checkpt:        &ethpb.Checkpoint{Root: r[:], Epoch: 1},
 			finalizedEpoch: 3,
 			wantErr:        false,
 		},
@@ -72,9 +69,7 @@ func TestService_VerifyWeakSubjectivityRoot(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			s := &Service{
-				beaconDB:         beaconDB,
-				wsRoot:           tt.wsRoot[:],
-				wsEpoch:          tt.wsEpoch,
+				cfg:              &Config{BeaconDB: beaconDB, WeakSubjectivityCheckpt: tt.checkpt},
 				wsVerified:       tt.wsVerified,
 				finalizedCheckpt: &ethpb.Checkpoint{Epoch: tt.finalizedEpoch},
 			}
--- a/beacon-chain/cache/BUILD.bazel
+++ b/beacon-chain/cache/BUILD.bazel
@@ -1,8 +1,8 @@
 load("@prysm//tools/go:def.bzl", "go_library")
 load("@io_bazel_rules_go//go:def.bzl", "go_test")

-# gazelle:ignore committee_disabled.go
-# gazelle:ignore proposer_indices_disabled.go
+# gazelle:exclude committee_disabled.go
+# gazelle:exclude proposer_indices_disabled.go
 go_library(
    name = "go_default_library",
    srcs = [
@@ -11,13 +11,13 @@ go_library(
        "committees.go",
        "common.go",
        "doc.go",
+        "proposer_indices_type.go",
        "skip_slot_cache.go",
        "subnet_ids.go",
-        "proposer_indices_type.go",
    ] + select({
        "//fuzz:fuzzing_enabled": [
            "committee_disabled.go",
-            "proposer_indices_disabled.go"
+            "proposer_indices_disabled.go",
        ],
        "//conditions:default": [
            "committee.go",
@@ -31,9 +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",
@@ -53,26 +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",
-        "cache_test.go",
+        "proposer_indices_test.go",
        "skip_slot_cache_test.go",
        "subnet_ids_test.go",
-        "proposer_indices_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/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",
+        "@org_golang_google_protobuf//proto:go_default_library",
    ],
 )
--- a/beacon-chain/cache/attestation_data.go
+++ b/beacon-chain/cache/attestation_data.go
@@ -11,7 +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/beacon-chain/state/stateV0"
 	"k8s.io/client-go/tools/cache"
 )

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

 	if exists && item != nil && item.(*attestationReqResWrapper).res != nil {
 		attestationCacheHit.Inc()
-		return state.CopyAttestationData(item.(*attestationReqResWrapper).res), nil
+		return stateV0.CopyAttestationData(item.(*attestationReqResWrapper).res), nil
 	}
 	attestationCacheMiss.Inc()
 	return nil, nil
--- a/beacon-chain/cache/attestation_data_test.go
+++ b/beacon-chain/cache/attestation_data_test.go
@@ -4,10 +4,10 @@ import (
 	"context"
 	"testing"

-	"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"
+	"google.golang.org/protobuf/proto"
 )

 func TestAttestationCache_RoundTrip(t *testing.T) {
--- a/beacon-chain/cache/checkpoint_state.go
+++ b/beacon-chain/cache/checkpoint_state.go
@@ -7,7 +7,7 @@ import (
 	"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"
 )

@@ -47,7 +47,7 @@ func NewCheckpointStateCache() *CheckpointStateCache {

 // 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)
@@ -60,7 +60,7 @@ func (c *CheckpointStateCache) StateByCheckpoint(cp *ethpb.Checkpoint) (*stateTr
 	if exists && item != nil {
 		checkpointStateHit.Inc()
 		// Copy here is unnecessary since the return will only be used to verify attestation signature.
-		return item.(*stateTrie.BeaconState), nil
+		return item.(iface.BeaconState), nil
 	}

 	checkpointStateMiss.Inc()
@@ -69,7 +69,7 @@ func (c *CheckpointStateCache) StateByCheckpoint(cp *ethpb.Checkpoint) (*stateTr

 // 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 *ethpb.Checkpoint, s *stateTrie.BeaconState) error {
+func (c *CheckpointStateCache) AddCheckpointState(cp *ethpb.Checkpoint, s iface.ReadOnlyBeaconState) error {
 	c.lock.Lock()
 	defer c.lock.Unlock()
 	h, err := hashutil.HashProto(cp)
--- a/beacon-chain/cache/checkpoint_state_test.go
+++ b/beacon-chain/cache/checkpoint_state_test.go
@@ -3,22 +3,23 @@ package cache
 import (
 	"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/params"
 	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
 	"github.com/prysmaticlabs/prysm/shared/testutil/require"
+	"google.golang.org/protobuf/proto"
 )

 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,
 	})
@@ -26,19 +27,23 @@ func TestCheckpointStateCache_StateByCheckpoint(t *testing.T) {

 	state, err := cache.StateByCheckpoint(cp1)
 	require.NoError(t, err)
-	assert.Equal(t, (*stateTrie.BeaconState)(nil), state, "Expected state not to exist in empty cache")
+	assert.Equal(t, iface.BeaconState(nil), state, "Expected state not to exist in empty cache")

 	require.NoError(t, cache.AddCheckpointState(cp1, st))

 	state, err = cache.StateByCheckpoint(cp1)
 	require.NoError(t, err)

-	if !proto.Equal(state.InnerStateUnsafe(), st.InnerStateUnsafe()) {
+	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,
 	})
 	require.NoError(t, err)
@@ -55,7 +60,7 @@ func TestCheckpointStateCache_StateByCheckpoint(t *testing.T) {

 func TestCheckpointStateCache_MaxSize(t *testing.T) {
 	c := NewCheckpointStateCache()
-	st, err := stateTrie.InitializeFromProto(&pb.BeaconState{
+	st, err := stateV0.InitializeFromProto(&pb.BeaconState{
 		Slot: 0,
 	})
 	require.NoError(t, err)
--- a/beacon-chain/cache/depositcache/BUILD.bazel
+++ b/beacon-chain/cache/depositcache/BUILD.bazel
@@ -16,6 +16,7 @@ go_library(
        "//shared/hashutil:go_default_library",
        "//shared/params:go_default_library",
        "//shared/trieutil: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_ethereumapis//eth/v1alpha1:go_default_library",
@@ -38,8 +39,8 @@ go_test(
        "//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",
+        "@org_golang_google_protobuf//proto:go_default_library",
    ],
 )
--- a/beacon-chain/cache/depositcache/deposits_cache.go
+++ b/beacon-chain/cache/depositcache/deposits_cache.go
@@ -12,6 +12,7 @@ import (
 	"sort"
 	"sync"

+	"github.com/pkg/errors"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
@@ -74,7 +75,7 @@ func New() (*DepositCache, error) {

 // InsertDeposit into the database. If deposit or block number are nil
 // then this method does nothing.
-func (dc *DepositCache) InsertDeposit(ctx context.Context, d *ethpb.Deposit, blockNum uint64, index int64, depositRoot [32]byte) {
+func (dc *DepositCache) InsertDeposit(ctx context.Context, d *ethpb.Deposit, blockNum uint64, index int64, depositRoot [32]byte) error {
 	ctx, span := trace.StartSpan(ctx, "DepositsCache.InsertDeposit")
 	defer span.End()
 	if d == nil {
@@ -84,15 +85,22 @@ func (dc *DepositCache) InsertDeposit(ctx context.Context, d *ethpb.Deposit, blo
 			"index":        index,
 			"deposit root": hex.EncodeToString(depositRoot[:]),
 		}).Warn("Ignoring nil deposit insertion")
-		return
+		return errors.New("nil deposit inserted into the cache")
 	}
 	dc.depositsLock.Lock()
 	defer dc.depositsLock.Unlock()
+
+	if int(index) != len(dc.deposits) {
+		return errors.Errorf("wanted deposit with index %d to be inserted but received %d", len(dc.deposits), index)
+	}
 	// 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()
+	return nil
 }

 // InsertDepositContainers inserts a set of deposit containers into our deposit cache.
@@ -165,7 +173,7 @@ func (dc *DepositCache) AllDeposits(ctx context.Context, untilBlk *big.Int) []*e
 	return deposits
 }

-// DepositsNumberAndRootAtHeight returns number of deposits made prior to blockheight and the
+// DepositsNumberAndRootAtHeight returns number of deposits made up to blockheight and the
 // root that corresponds to the latest deposit at that blockheight.
 func (dc *DepositCache) DepositsNumberAndRootAtHeight(ctx context.Context, blockHeight *big.Int) (uint64, [32]byte) {
 	ctx, span := trace.StartSpan(ctx, "DepositsCache.DepositsNumberAndRootAtHeight")
--- a/beacon-chain/cache/depositcache/deposits_cache_test.go
+++ b/beacon-chain/cache/depositcache/deposits_cache_test.go
@@ -26,7 +26,7 @@ func TestInsertDeposit_LogsOnNilDepositInsertion(t *testing.T) {
 	dc, err := New()
 	require.NoError(t, err)

-	dc.InsertDeposit(context.Background(), nil, 1, 0, [32]byte{})
+	assert.ErrorContains(t, "nil deposit inserted into the cache", 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)
@@ -37,37 +37,52 @@ func TestInsertDeposit_MaintainsSortedOrderByIndex(t *testing.T) {
 	require.NoError(t, err)

 	insertions := []struct {
-		blkNum  uint64
-		deposit *ethpb.Deposit
-		index   int64
+		blkNum      uint64
+		deposit     *ethpb.Deposit
+		index       int64
+		expectedErr string
 	}{
 		{
-			blkNum:  0,
-			deposit: &ethpb.Deposit{},
-			index:   0,
+			blkNum:      0,
+			deposit:     &ethpb.Deposit{},
+			index:       0,
+			expectedErr: "",
 		},
 		{
-			blkNum:  0,
-			deposit: &ethpb.Deposit{},
-			index:   3,
+			blkNum:      0,
+			deposit:     &ethpb.Deposit{},
+			index:       3,
+			expectedErr: "wanted deposit with index 1 to be inserted but received 3",
 		},
 		{
-			blkNum:  0,
-			deposit: &ethpb.Deposit{},
-			index:   1,
+			blkNum:      0,
+			deposit:     &ethpb.Deposit{},
+			index:       1,
+			expectedErr: "",
 		},
 		{
-			blkNum:  0,
-			deposit: &ethpb.Deposit{},
-			index:   4,
+			blkNum:      0,
+			deposit:     &ethpb.Deposit{},
+			index:       4,
+			expectedErr: "wanted deposit with index 2 to be inserted but received 4",
+		},
+		{
+			blkNum:      0,
+			deposit:     &ethpb.Deposit{},
+			index:       2,
+			expectedErr: "",
 		},
 	}

 	for _, ins := range insertions {
-		dc.InsertDeposit(context.Background(), ins.deposit, ins.blkNum, ins.index, [32]byte{})
+		if ins.expectedErr != "" {
+			assert.ErrorContains(t, ins.expectedErr, dc.InsertDeposit(context.Background(), ins.deposit, ins.blkNum, ins.index, [32]byte{}))
+		} else {
+			assert.NoError(t, dc.InsertDeposit(context.Background(), ins.deposit, ins.blkNum, ins.index, [32]byte{}))
+		}
 	}

-	expectedIndices := []int64{0, 1, 3, 4}
+	expectedIndices := []int64{0, 1, 2}
 	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))
@@ -154,121 +169,148 @@ func TestAllDeposits_FiltersDepositUpToAndIncludingBlockNumber(t *testing.T) {
 	assert.Equal(t, 5, len(d))
 }

-func TestDepositsNumberAndRootAtHeight_ReturnsAppropriateCountAndRoot(t *testing.T) {
-	dc, err := New()
-	require.NoError(t, err)
+func TestDepositsNumberAndRootAtHeight(t *testing.T) {
+	wantedRoot := bytesutil.PadTo([]byte("root"), 32)
+	t.Run("requesting_last_item_works", func(t *testing.T) {
+		dc, err := New()
+		require.NoError(t, err)
+		dc.deposits = []*dbpb.DepositContainer{
+			{
+				Eth1BlockHeight: 10,
+				Index:           0,
+				Deposit:         &ethpb.Deposit{},
+			},
+			{
+				Eth1BlockHeight: 10,
+				Index:           1,
+				Deposit:         &ethpb.Deposit{},
+			},
+			{
+				Eth1BlockHeight: 11,
+				Index:           2,
+				Deposit:         &ethpb.Deposit{},
+			},
+			{
+				Eth1BlockHeight: 13,
+				Index:           3,
+				Deposit:         &ethpb.Deposit{},
+				DepositRoot:     wantedRoot,
+			},
+		}
+		n, root := dc.DepositsNumberAndRootAtHeight(context.Background(), big.NewInt(13))
+		assert.Equal(t, 4, int(n))
+		require.DeepEqual(t, wantedRoot, root[:])
+	})
+	t.Run("only_one_item", func(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),
-				},
+		dc.deposits = []*dbpb.DepositContainer{
+			{
+				Eth1BlockHeight: 10,
+				Index:           0,
+				Deposit:         &ethpb.Deposit{},
+				DepositRoot:     wantedRoot,
 			},
-		},
-		{
-			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(10))
+		assert.Equal(t, 1, int(n))
+		require.DeepEqual(t, wantedRoot, root[:])
+	})
+	t.Run("none_at_height_some_below", func(t *testing.T) {
+		dc, err := New()
+		require.NoError(t, err)

-	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),
-				},
+		dc.deposits = []*dbpb.DepositContainer{
+			{
+				Eth1BlockHeight: 8,
+				Index:           0,
+				Deposit:         &ethpb.Deposit{},
 			},
-			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),
-				},
+			{
+				Eth1BlockHeight: 9,
+				Index:           1,
+				Deposit:         &ethpb.Deposit{},
+				DepositRoot:     wantedRoot,
 			},
-			DepositRoot: bytesutil.PadTo([]byte("root"), 32),
-		},
-	}
+			{
+				Eth1BlockHeight: 11,
+				Index:           2,
+				Deposit:         &ethpb.Deposit{},
+			},
+		}
+		n, root := dc.DepositsNumberAndRootAtHeight(context.Background(), big.NewInt(10))
+		assert.Equal(t, 2, int(n))
+		require.DeepEqual(t, wantedRoot, root[:])
+	})
+	t.Run("none_at_height_none_below", func(t *testing.T) {
+		dc, err := New()
+		require.NoError(t, err)

-	n, root := dc.DepositsNumberAndRootAtHeight(context.Background(), big.NewInt(2))
-	assert.Equal(t, 0, int(n))
-	assert.Equal(t, [32]byte{}, root)
+		dc.deposits = []*dbpb.DepositContainer{
+			{
+				Eth1BlockHeight: 8,
+				Index:           0,
+				Deposit:         &ethpb.Deposit{},
+				DepositRoot:     wantedRoot,
+			},
+		}
+		n, root := dc.DepositsNumberAndRootAtHeight(context.Background(), big.NewInt(7))
+		assert.Equal(t, 0, int(n))
+		require.DeepEqual(t, params.BeaconConfig().ZeroHash, root)
+	})
+	t.Run("none_at_height_one_below", func(t *testing.T) {
+		dc, err := New()
+		require.NoError(t, err)
+
+		dc.deposits = []*dbpb.DepositContainer{
+			{
+				Eth1BlockHeight: 8,
+				Index:           0,
+				Deposit:         &ethpb.Deposit{},
+				DepositRoot:     wantedRoot,
+			},
+		}
+		n, root := dc.DepositsNumberAndRootAtHeight(context.Background(), big.NewInt(10))
+		assert.Equal(t, 1, int(n))
+		require.DeepEqual(t, wantedRoot, root[:])
+	})
+	t.Run("some_greater_some_lower", func(t *testing.T) {
+		dc, err := New()
+		require.NoError(t, err)
+
+		dc.deposits = []*dbpb.DepositContainer{
+			{
+				Eth1BlockHeight: 8,
+				Index:           0,
+				Deposit:         &ethpb.Deposit{},
+			},
+			{
+				Eth1BlockHeight: 8,
+				Index:           1,
+				Deposit:         &ethpb.Deposit{},
+			},
+			{
+				Eth1BlockHeight: 9,
+				Index:           2,
+				Deposit:         &ethpb.Deposit{},
+				DepositRoot:     wantedRoot,
+			},
+			{
+				Eth1BlockHeight: 10,
+				Index:           3,
+				Deposit:         &ethpb.Deposit{},
+			},
+			{
+				Eth1BlockHeight: 10,
+				Index:           4,
+				Deposit:         &ethpb.Deposit{},
+			},
+		}
+		n, root := dc.DepositsNumberAndRootAtHeight(context.Background(), big.NewInt(9))
+		assert.Equal(t, 3, int(n))
+		require.DeepEqual(t, wantedRoot, root[:])
+	})
 }

 func TestDepositByPubkey_ReturnsFirstMatchingDeposit(t *testing.T) {
@@ -606,7 +648,7 @@ func TestPruneProofs_Ok(t *testing.T) {
 	}

 	for _, ins := range deposits {
-		dc.InsertDeposit(context.Background(), ins.deposit, ins.blkNum, ins.index, [32]byte{})
+		assert.NoError(t, dc.InsertDeposit(context.Background(), ins.deposit, ins.blkNum, ins.index, [32]byte{}))
 	}

 	require.NoError(t, dc.PruneProofs(context.Background(), 1))
@@ -649,7 +691,7 @@ func TestPruneProofs_SomeAlreadyPruned(t *testing.T) {
 	}

 	for _, ins := range deposits {
-		dc.InsertDeposit(context.Background(), ins.deposit, ins.blkNum, ins.index, [32]byte{})
+		assert.NoError(t, dc.InsertDeposit(context.Background(), ins.deposit, ins.blkNum, ins.index, [32]byte{}))
 	}

 	require.NoError(t, dc.PruneProofs(context.Background(), 2))
@@ -689,7 +731,7 @@ func TestPruneProofs_PruneAllWhenDepositIndexTooBig(t *testing.T) {
 	}

 	for _, ins := range deposits {
-		dc.InsertDeposit(context.Background(), ins.deposit, ins.blkNum, ins.index, [32]byte{})
+		assert.NoError(t, dc.InsertDeposit(context.Background(), ins.deposit, ins.blkNum, ins.index, [32]byte{}))
 	}

 	require.NoError(t, dc.PruneProofs(context.Background(), 99))
@@ -732,7 +774,7 @@ func TestPruneProofs_CorrectlyHandleLastIndex(t *testing.T) {
 	}

 	for _, ins := range deposits {
-		dc.InsertDeposit(context.Background(), ins.deposit, ins.blkNum, ins.index, [32]byte{})
+		assert.NoError(t, dc.InsertDeposit(context.Background(), ins.deposit, ins.blkNum, ins.index, [32]byte{}))
 	}

 	require.NoError(t, dc.PruneProofs(context.Background(), 4))
--- a/beacon-chain/cache/depositcache/pending_deposits_test.go
+++ b/beacon-chain/cache/depositcache/pending_deposits_test.go
@@ -5,11 +5,11 @@ import (
 	"math/big"
 	"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"
+	"google.golang.org/protobuf/proto"
 )

 var _ PendingDepositsFetcher = (*DepositCache)(nil)
@@ -90,7 +90,7 @@ func TestPendingDeposits_OK(t *testing.T) {
 		{Proof: [][]byte{[]byte("A")}},
 		{Proof: [][]byte{[]byte("B")}},
 	}
-	assert.DeepEqual(t, expected, deposits)
+	assert.DeepSSZEqual(t, expected, deposits)

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

@@ -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, r [32]byte) (*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 {
@@ -97,7 +97,7 @@ func (c *SkipSlotCache) Get(ctx context.Context, r [32]byte) (*stateTrie.BeaconS
 	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))
@@ -136,7 +136,7 @@ func (c *SkipSlotCache) MarkNotInProgress(r [32]byte) error {
 }

 // Put the response in the cache.
-func (c *SkipSlotCache) Put(_ context.Context, r [32]byte, state *stateTrie.BeaconState) error {
+func (c *SkipSlotCache) Put(_ context.Context, r [32]byte, state iface.BeaconState) error {
 	if c.disabled {
 		return nil
 	}
--- a/beacon-chain/cache/skip_slot_cache_test.go
+++ b/beacon-chain/cache/skip_slot_cache_test.go
@@ -5,7 +5,8 @@ import (
 	"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"
@@ -18,11 +19,11 @@ func TestSkipSlotCache_RoundTrip(t *testing.T) {
 	r := [32]byte{'a'}
 	state, err := c.Get(ctx, r)
 	require.NoError(t, err)
-	assert.Equal(t, (*stateTrie.BeaconState)(nil), state, "Empty cache returned an object")
+	assert.Equal(t, iface.BeaconState(nil), state, "Empty cache returned an object")

 	require.NoError(t, c.MarkInProgress(r))

-	state, err = stateTrie.InitializeFromProto(&pb.BeaconState{
+	state, err = stateV0.InitializeFromProto(&pb.BeaconState{
 		Slot: 10,
 	})
 	require.NoError(t, err)
--- a/beacon-chain/core/blocks/BUILD.bazel
+++ b/beacon-chain/core/blocks/BUILD.bazel
@@ -21,13 +21,14 @@ go_library(
        "//beacon-chain:__subpackages__",
        "//fuzz:__pkg__",
        "//shared/testutil:__pkg__",
+        "//spectest:__subpackages__",
        "//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/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",
@@ -39,12 +40,12 @@ go_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_sirupsen_logrus//:go_default_library",
        "@io_opencensus_go//trace:go_default_library",
+        "@org_golang_google_protobuf//proto:go_default_library",
    ],
 )

@@ -71,8 +72,10 @@ go_test(
    shard_count = 2,
    deps = [
        "//beacon-chain/core/helpers:go_default_library",
+        "//beacon-chain/core/validators:go_default_library",
        "//beacon-chain/p2p/types:go_default_library",
-        "//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/aggregation:go_default_library",
        "//shared/aggregation/attestations:go_default_library",
@@ -84,11 +87,11 @@ go_test(
        "//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_sirupsen_logrus//:go_default_library",
+        "@org_golang_google_protobuf//proto:go_default_library",
    ],
 )
--- a/beacon-chain/core/blocks/attestation.go
+++ b/beacon-chain/core/blocks/attestation.go
@@ -8,7 +8,7 @@ import (
 	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"
+	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"
@@ -20,9 +20,9 @@ import (
 // records.
 func ProcessAttestations(
 	ctx context.Context,
-	beaconState *stateTrie.BeaconState,
+	beaconState iface.BeaconState,
 	b *ethpb.SignedBeaconBlock,
-) (*stateTrie.BeaconState, error) {
+) (iface.BeaconState, error) {
 	if err := helpers.VerifyNilBeaconBlock(b); err != nil {
 		return nil, err
 	}
@@ -64,13 +64,13 @@ func ProcessAttestations(
 //        assert data.source == state.previous_justified_checkpoint
 //        state.previous_epoch_attestations.append(pending_attestation)
 //
-//    # Check signature
+//    # Verify signature
 //    assert is_valid_indexed_attestation(state, get_indexed_attestation(state, attestation))
 func ProcessAttestation(
 	ctx context.Context,
-	beaconState *stateTrie.BeaconState,
+	beaconState iface.BeaconState,
 	att *ethpb.Attestation,
-) (*stateTrie.BeaconState, error) {
+) (iface.BeaconState, error) {
 	beaconState, err := ProcessAttestationNoVerifySignature(ctx, beaconState, att)
 	if err != nil {
 		return nil, err
@@ -82,9 +82,9 @@ func ProcessAttestation(
 // records. The only difference would be that the attestation signature would not be verified.
 func ProcessAttestationsNoVerifySignature(
 	ctx context.Context,
-	beaconState *stateTrie.BeaconState,
+	beaconState iface.BeaconState,
 	b *ethpb.SignedBeaconBlock,
-) (*stateTrie.BeaconState, error) {
+) (iface.BeaconState, error) {
 	if err := helpers.VerifyNilBeaconBlock(b); err != nil {
 		return nil, err
 	}
@@ -103,35 +103,46 @@ func ProcessAttestationsNoVerifySignature(
 // used before processing attestation with the beacon state.
 func VerifyAttestationNoVerifySignature(
 	ctx context.Context,
-	beaconState *stateTrie.BeaconState,
+	beaconState iface.ReadOnlyBeaconState,
 	att *ethpb.Attestation,
-) (*stateTrie.BeaconState, error) {
+) error {
 	ctx, span := trace.StartSpan(ctx, "core.VerifyAttestationNoVerifySignature")
 	defer span.End()

 	if err := helpers.ValidateNilAttestation(att); err != nil {
-		return nil, err
+		return err
 	}
 	currEpoch := helpers.CurrentEpoch(beaconState)
 	prevEpoch := helpers.PrevEpoch(beaconState)
 	data := att.Data
 	if data.Target.Epoch != prevEpoch && data.Target.Epoch != currEpoch {
-		return nil, fmt.Errorf(
+		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 nil, err
+		return err
 	}

 	s := att.Data.Slot
 	minInclusionCheck := s+params.BeaconConfig().MinAttestationInclusionDelay <= beaconState.Slot()
 	epochInclusionCheck := beaconState.Slot() <= s+params.BeaconConfig().SlotsPerEpoch
 	if !minInclusionCheck {
-		return nil, fmt.Errorf(
+		return fmt.Errorf(
 			"attestation slot %d + inclusion delay %d > state slot %d",
 			s,
 			params.BeaconConfig().MinAttestationInclusionDelay,
@@ -139,7 +150,7 @@ func VerifyAttestationNoVerifySignature(
 		)
 	}
 	if !epochInclusionCheck {
-		return nil, fmt.Errorf(
+		return fmt.Errorf(
 			"state slot %d > attestation slot %d + SLOTS_PER_EPOCH %d",
 			beaconState.Slot(),
 			s,
@@ -148,41 +159,41 @@ func VerifyAttestationNoVerifySignature(
 	}
 	activeValidatorCount, err := helpers.ActiveValidatorCount(beaconState, att.Data.Target.Epoch)
 	if err != nil {
-		return nil, err
+		return err
 	}
 	c := helpers.SlotCommitteeCount(activeValidatorCount)
 	if uint64(att.Data.CommitteeIndex) >= c {
-		return nil, fmt.Errorf("committee index %d >= committee count %d", 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 nil, errors.Wrap(err, "could not verify attestation bitfields")
+		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 nil, err
+		return err
 	}
 	indexedAtt, err := attestationutil.ConvertToIndexed(ctx, att, committee)
 	if err != nil {
-		return nil, err
+		return err
 	}

-	return nil, attestationutil.IsValidAttestationIndices(ctx, indexedAtt)
+	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 *stateTrie.BeaconState,
+	beaconState iface.BeaconState,
 	att *ethpb.Attestation,
-) (*stateTrie.BeaconState, error) {
+) (iface.BeaconState, error) {
 	ctx, span := trace.StartSpan(ctx, "core.ProcessAttestationNoVerifySignature")
 	defer span.End()

-	if _, err := VerifyAttestationNoVerifySignature(ctx, beaconState, att); err != nil {
+	if err := VerifyAttestationNoVerifySignature(ctx, beaconState, att); err != nil {
 		return nil, err
 	}

@@ -201,16 +212,10 @@ func ProcessAttestationNoVerifySignature(
 	}

 	if data.Target.Epoch == currEpoch {
-		if !beaconState.MatchCurrentJustifiedCheckpoint(data.Source) {
-			return nil, errors.New("source check point not equal to current justified checkpoint")
-		}
 		if err := beaconState.AppendCurrentEpochAttestations(pendingAtt); err != nil {
 			return nil, err
 		}
 	} else {
-		if !beaconState.MatchPreviousJustifiedCheckpoint(data.Source) {
-			return nil, errors.New("source check point not equal to previous justified checkpoint")
-		}
 		if err := beaconState.AppendPreviousEpochAttestations(pendingAtt); err != nil {
 			return nil, err
 		}
@@ -221,7 +226,7 @@ func ProcessAttestationNoVerifySignature(

 // VerifyAttestationSignature converts and attestation into an indexed attestation and verifies
 // the signature in that attestation.
-func VerifyAttestationSignature(ctx context.Context, beaconState *stateTrie.BeaconState, att *ethpb.Attestation) error {
+func VerifyAttestationSignature(ctx context.Context, beaconState iface.ReadOnlyBeaconState, att *ethpb.Attestation) error {
 	if err := helpers.ValidateNilAttestation(att); err != nil {
 		return err
 	}
@@ -252,14 +257,19 @@ func VerifyAttestationSignature(ctx context.Context, beaconState *stateTrie.Beac
 //    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 *stateTrie.BeaconState, indexedAtt *ethpb.IndexedAttestation) error {
+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())
+	domain, err := helpers.Domain(
+		beaconState.Fork(),
+		indexedAtt.Data.Target.Epoch,
+		params.BeaconConfig().DomainBeaconAttester,
+		beaconState.GenesisValidatorRoot(),
+	)
 	if err != nil {
 		return err
 	}
--- a/beacon-chain/core/blocks/attestation_regression_test.go
+++ b/beacon-chain/core/blocks/attestation_regression_test.go
@@ -6,9 +6,13 @@ import (
 	"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"
+	"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"
 )

@@ -33,7 +37,7 @@ func TestProcessAttestationNoVerifySignature_BeaconFuzzIssue78(t *testing.T) {
 	if err := spb.UnmarshalSSZ(stateData); err != nil {
 		t.Fatal(err)
 	}
-	st, err := state.InitializeFromProtoUnsafe(spb)
+	st, err := stateV0.InitializeFromProtoUnsafe(spb)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -42,3 +46,35 @@ func TestProcessAttestationNoVerifySignature_BeaconFuzzIssue78(t *testing.T) {
 	_, 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
@@ -10,7 +10,7 @@ import (
 	"github.com/prysmaticlabs/go-bitfield"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	"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"
@@ -68,7 +68,7 @@ func TestProcessAttestations_NeitherCurrentNorPrevEpoch(t *testing.T) {
 	pfc := beaconState.PreviousJustifiedCheckpoint()
 	pfc.Root = []byte("hello-world")
 	require.NoError(t, beaconState.SetPreviousJustifiedCheckpoint(pfc))
-	require.NoError(t, beaconState.SetPreviousEpochAttestations([]*pb.PendingAttestation{}))
+	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)",
@@ -101,7 +101,7 @@ func TestProcessAttestations_CurrentEpochFFGDataMismatches(t *testing.T) {
 	cfc := beaconState.CurrentJustifiedCheckpoint()
 	cfc.Root = []byte("hello-world")
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cfc))
-	require.NoError(t, beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))

 	want := "source check point not equal to current justified checkpoint"
 	_, err := blocks.ProcessAttestations(context.Background(), beaconState, b)
@@ -139,7 +139,7 @@ func TestProcessAttestations_PrevEpochFFGDataMismatches(t *testing.T) {
 	pfc := beaconState.PreviousJustifiedCheckpoint()
 	pfc.Root = []byte("hello-world")
 	require.NoError(t, beaconState.SetPreviousJustifiedCheckpoint(pfc))
-	require.NoError(t, beaconState.SetPreviousEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendPreviousEpochAttestations(&pb.PendingAttestation{}))

 	want := "source check point not equal to previous justified checkpoint"
 	_, err = blocks.ProcessAttestations(context.Background(), beaconState, b)
@@ -175,7 +175,7 @@ func TestProcessAttestations_InvalidAggregationBitsLength(t *testing.T) {
 	cfc := beaconState.CurrentJustifiedCheckpoint()
 	cfc.Root = []byte("hello-world")
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cfc))
-	require.NoError(t, beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}))
+	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)
@@ -200,7 +200,7 @@ func TestProcessAttestations_OK(t *testing.T) {
 	cfc := beaconState.CurrentJustifiedCheckpoint()
 	cfc.Root = mockRoot[:]
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cfc))
-	require.NoError(t, beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))

 	committee, err := helpers.BeaconCommitteeFromState(beaconState, att.Data.Slot, att.Data.CommitteeIndex)
 	require.NoError(t, err)
@@ -242,7 +242,7 @@ func TestProcessAggregatedAttestation_OverlappingBits(t *testing.T) {
 	cfc := beaconState.CurrentJustifiedCheckpoint()
 	cfc.Root = bytesutil.PadTo([]byte("hello-world"), 32)
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cfc))
-	require.NoError(t, beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))

 	committee, err := helpers.BeaconCommitteeFromState(beaconState, att1.Data.Slot, att1.Data.CommitteeIndex)
 	require.NoError(t, err)
@@ -305,7 +305,7 @@ func TestProcessAggregatedAttestation_NoOverlappingBits(t *testing.T) {
 	cfc := beaconState.CurrentJustifiedCheckpoint()
 	cfc.Root = mockRoot[:]
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cfc))
-	require.NoError(t, beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))

 	committee, err := helpers.BeaconCommitteeFromState(beaconState, att1.Data.Slot, att1.Data.CommitteeIndex)
 	require.NoError(t, err)
@@ -366,7 +366,7 @@ func TestVerifyAttestationNoVerifySignature_IncorrectSlotTargetEpoch(t *testing.
 		},
 	})
 	wanted := "slot 32 does not match target epoch 0"
-	_, err := blocks.VerifyAttestationNoVerifySignature(context.TODO(), beaconState, att)
+	err := blocks.VerifyAttestationNoVerifySignature(context.TODO(), beaconState, att)
 	assert.ErrorContains(t, wanted, err)
 }

@@ -395,7 +395,7 @@ func TestProcessAttestationsNoVerify_OK(t *testing.T) {
 	ckp := beaconState.CurrentJustifiedCheckpoint()
 	copy(ckp.Root, "hello-world")
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(ckp))
-	require.NoError(t, beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))

 	_, err = blocks.ProcessAttestationNoVerifySignature(context.TODO(), beaconState, att)
 	assert.NoError(t, err)
@@ -426,9 +426,9 @@ func TestVerifyAttestationNoVerifySignature_OK(t *testing.T) {
 	ckp := beaconState.CurrentJustifiedCheckpoint()
 	copy(ckp.Root, "hello-world")
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(ckp))
-	require.NoError(t, beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))

-	_, err = blocks.VerifyAttestationNoVerifySignature(context.TODO(), beaconState, att)
+	err = blocks.VerifyAttestationNoVerifySignature(context.TODO(), beaconState, att)
 	assert.NoError(t, err)
 }

@@ -452,8 +452,8 @@ func TestVerifyAttestationNoVerifySignature_BadAttIdx(t *testing.T) {
 	ckp := beaconState.CurrentJustifiedCheckpoint()
 	copy(ckp.Root, "hello-world")
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(ckp))
-	require.NoError(t, beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}))
-	_, err := blocks.VerifyAttestationNoVerifySignature(context.TODO(), beaconState, att)
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
+	err := blocks.VerifyAttestationNoVerifySignature(context.TODO(), beaconState, att)
 	require.ErrorContains(t, "committee index 100 >= committee count 1", err)
 }

@@ -466,7 +466,7 @@ func TestConvertToIndexed_OK(t *testing.T) {
 		}
 	}

-	state, err := stateTrie.InitializeFromProto(&pb.BeaconState{
+	state, err := stateV0.InitializeFromProto(&pb.BeaconState{
 		Slot:        5,
 		Validators:  validators,
 		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
@@ -524,7 +524,7 @@ func TestVerifyIndexedAttestation_OK(t *testing.T) {
 		}
 	}

-	state, err := stateTrie.InitializeFromProto(&pb.BeaconState{
+	state, err := stateV0.InitializeFromProto(&pb.BeaconState{
 		Slot:       5,
 		Validators: validators,
 		Fork: &pb.Fork{
@@ -611,7 +611,7 @@ func TestValidateIndexedAttestation_AboveMaxLength(t *testing.T) {
 	}

 	want := "validator indices count exceeds MAX_VALIDATORS_PER_COMMITTEE"
-	err := blocks.VerifyIndexedAttestation(context.Background(), &stateTrie.BeaconState{}, indexedAtt1)
+	err := blocks.VerifyIndexedAttestation(context.Background(), &stateV0.BeaconState{}, indexedAtt1)
 	assert.ErrorContains(t, want, err)
 }

--- a/beacon-chain/core/blocks/attester_slashing.go
+++ b/beacon-chain/core/blocks/attester_slashing.go
@@ -8,8 +8,6 @@ import (
 	types "github.com/prysmaticlabs/eth2-types"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	v "github.com/prysmaticlabs/prysm/beacon-chain/core/validators"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
 	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
 	"github.com/prysmaticlabs/prysm/shared/attestationutil"
 	"github.com/prysmaticlabs/prysm/shared/slashutil"
@@ -37,15 +35,11 @@ import (
 //    assert slashed_any
 func ProcessAttesterSlashings(
 	ctx context.Context,
-	beaconState *stateTrie.BeaconState,
-	b *ethpb.SignedBeaconBlock,
-) (*stateTrie.BeaconState, error) {
-	if err := helpers.VerifyNilBeaconBlock(b); err != nil {
-		return nil, err
-	}
-
-	body := b.Block.Body
-	for idx, slashing := range body.AttesterSlashings {
+	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)
 		}
@@ -63,7 +57,7 @@ func ProcessAttesterSlashings(
 				return nil, err
 			}
 			if helpers.IsSlashableValidator(val.ActivationEpoch(), val.WithdrawableEpoch(), val.Slashed(), currentEpoch) {
-				beaconState, err = v.SlashValidator(beaconState, types.ValidatorIndex(validatorIndex))
+				beaconState, err = slashFunc(beaconState, types.ValidatorIndex(validatorIndex))
 				if err != nil {
 					return nil, errors.Wrapf(err, "could not slash validator index %d",
 						validatorIndex)
@@ -79,7 +73,7 @@ func ProcessAttesterSlashings(
 }

 // VerifyAttesterSlashing validates the attestation data in both attestations in the slashing object.
-func VerifyAttesterSlashing(ctx context.Context, beaconState *stateTrie.BeaconState, slashing *ethpb.AttesterSlashing) error {
+func VerifyAttesterSlashing(ctx context.Context, beaconState iface.ReadOnlyBeaconState, slashing *ethpb.AttesterSlashing) error {
 	if slashing == nil {
 		return errors.New("nil slashing")
 	}
--- a/beacon-chain/core/blocks/attester_slashing_test.go
+++ b/beacon-chain/core/blocks/attester_slashing_test.go
@@ -8,7 +8,8 @@ import (
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	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/bls"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
@@ -46,7 +47,7 @@ func TestProcessAttesterSlashings_DataNotSlashable(t *testing.T) {
 	var registry []*ethpb.Validator
 	currentSlot := types.Slot(0)

-	beaconState, err := stateTrie.InitializeFromProto(&pb.BeaconState{
+	beaconState, err := stateV0.InitializeFromProto(&pb.BeaconState{
 		Validators: registry,
 		Slot:       currentSlot,
 	})
@@ -57,7 +58,7 @@ func TestProcessAttesterSlashings_DataNotSlashable(t *testing.T) {
 			AttesterSlashings: slashings,
 		},
 	}
-	_, err = blocks.ProcessAttesterSlashings(context.Background(), beaconState, b)
+	_, err = blocks.ProcessAttesterSlashings(context.Background(), beaconState, b.Block.Body.AttesterSlashings, v.SlashValidator)
 	assert.ErrorContains(t, "attestations are not slashable", err)
 }

@@ -65,7 +66,7 @@ func TestProcessAttesterSlashings_IndexedAttestationFailedToVerify(t *testing.T)
 	var registry []*ethpb.Validator
 	currentSlot := types.Slot(0)

-	beaconState, err := stateTrie.InitializeFromProto(&pb.BeaconState{
+	beaconState, err := stateV0.InitializeFromProto(&pb.BeaconState{
 		Validators: registry,
 		Slot:       currentSlot,
 	})
@@ -92,7 +93,7 @@ func TestProcessAttesterSlashings_IndexedAttestationFailedToVerify(t *testing.T)
 		},
 	}

-	_, err = blocks.ProcessAttesterSlashings(context.Background(), beaconState, b)
+	_, err = blocks.ProcessAttesterSlashings(context.Background(), beaconState, b.Block.Body.AttesterSlashings, v.SlashValidator)
 	assert.ErrorContains(t, "validator indices count exceeds MAX_VALIDATORS_PER_COMMITTEE", err)
 }

@@ -144,7 +145,7 @@ func TestProcessAttesterSlashings_AppliesCorrectStatus(t *testing.T) {
 		},
 	}

-	newState, err := blocks.ProcessAttesterSlashings(context.Background(), beaconState, b)
+	newState, err := blocks.ProcessAttesterSlashings(context.Background(), beaconState, b.Block.Body.AttesterSlashings, v.SlashValidator)
 	require.NoError(t, err)
 	newRegistry := newState.Validators()

--- a/beacon-chain/core/blocks/block_operations_fuzz_test.go
+++ b/beacon-chain/core/blocks/block_operations_fuzz_test.go
@@ -7,7 +7,8 @@ import (
 	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/shared/testutil/require"
@@ -22,7 +23,7 @@ func TestFuzzProcessAttestationNoVerify_10000(t *testing.T) {
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(att)
-		s, err := stateTrie.InitializeFromProtoUnsafe(state)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
 		require.NoError(t, err)
 		_, err = ProcessAttestationNoVerifySignature(ctx, s, att)
 		_ = err
@@ -38,7 +39,7 @@ func TestFuzzProcessBlockHeader_10000(t *testing.T) {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(block)

-		s, err := stateTrie.InitializeFromProtoUnsafe(state)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
 		require.NoError(t, err)
 		_, err = ProcessBlockHeader(context.Background(), s, block)
 		_ = err
@@ -71,14 +72,14 @@ func TestFuzzverifyDepositDataSigningRoot_10000(t *testing.T) {

 func TestFuzzProcessEth1DataInBlock_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
-	b := &eth.SignedBeaconBlock{}
-	state := &stateTrie.BeaconState{}
+	e := &eth.Eth1Data{}
+	state := &stateV0.BeaconState{}
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
-		fuzzer.Fuzz(b)
-		s, err := ProcessEth1DataInBlock(context.Background(), state, b)
+		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, b)
+			t.Fatalf("state should be nil on err. found: %v on error: %v for state: %v and eth1data: %v", s, err, state, e)
 		}
 	}
 }
@@ -103,7 +104,7 @@ func TestFuzzEth1DataHasEnoughSupport_10000(t *testing.T) {
 	for i := 0; i < 100000; i++ {
 		fuzzer.Fuzz(eth1data)
 		fuzzer.Fuzz(&stateVotes)
-		s, err := stateTrie.InitializeFromProto(&pb.BeaconState{
+		s, err := stateV0.InitializeFromProto(&pb.BeaconState{
 			Eth1DataVotes: stateVotes,
 		})
 		require.NoError(t, err)
@@ -121,9 +122,9 @@ func TestFuzzProcessBlockHeaderNoVerify_10000(t *testing.T) {
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(block)
-		s, err := stateTrie.InitializeFromProtoUnsafe(state)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
 		require.NoError(t, err)
-		_, err = ProcessBlockHeaderNoVerify(s, block)
+		_, err = ProcessBlockHeaderNoVerify(s, block.Slot, block.ProposerIndex, block.ParentRoot, []byte{})
 		_ = err
 	}
 }
@@ -136,7 +137,7 @@ func TestFuzzProcessRandao_10000(t *testing.T) {
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(b)
-		s, err := stateTrie.InitializeFromProtoUnsafe(state)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
 		require.NoError(t, err)
 		r, err := ProcessRandao(context.Background(), s, b)
 		if err != nil && r != nil {
@@ -153,9 +154,9 @@ func TestFuzzProcessRandaoNoVerify_10000(t *testing.T) {
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(blockBody)
-		s, err := stateTrie.InitializeFromProtoUnsafe(state)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
 		require.NoError(t, err)
-		r, err := ProcessRandaoNoVerify(s, blockBody)
+		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)
 		}
@@ -165,16 +166,16 @@ func TestFuzzProcessRandaoNoVerify_10000(t *testing.T) {
 func TestFuzzProcessProposerSlashings_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
 	state := &pb.BeaconState{}
-	b := &eth.SignedBeaconBlock{}
+	p := &eth.ProposerSlashing{}
 	ctx := context.Background()
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
-		fuzzer.Fuzz(b)
-		s, err := stateTrie.InitializeFromProtoUnsafe(state)
+		fuzzer.Fuzz(p)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
 		require.NoError(t, err)
-		r, err := ProcessProposerSlashings(ctx, s, b)
+		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, b)
+			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and slashing: %v", r, err, state, p)
 		}
 	}
 }
@@ -186,7 +187,7 @@ func TestFuzzVerifyProposerSlashing_10000(t *testing.T) {
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(proposerSlashing)
-		s, err := stateTrie.InitializeFromProtoUnsafe(state)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
 		require.NoError(t, err)
 		err = VerifyProposerSlashing(s, proposerSlashing)
 		_ = err
@@ -196,16 +197,16 @@ func TestFuzzVerifyProposerSlashing_10000(t *testing.T) {
 func TestFuzzProcessAttesterSlashings_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
 	state := &pb.BeaconState{}
-	b := &eth.SignedBeaconBlock{}
+	a := &eth.AttesterSlashing{}
 	ctx := context.Background()
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
-		fuzzer.Fuzz(b)
-		s, err := stateTrie.InitializeFromProtoUnsafe(state)
+		fuzzer.Fuzz(a)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
 		require.NoError(t, err)
-		r, err := ProcessAttesterSlashings(ctx, s, b)
+		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, b)
+			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and slashing: %v", r, err, state, a)
 		}
 	}
 }
@@ -218,7 +219,7 @@ func TestFuzzVerifyAttesterSlashing_10000(t *testing.T) {
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(attesterSlashing)
-		s, err := stateTrie.InitializeFromProtoUnsafe(state)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
 		require.NoError(t, err)
 		err = VerifyAttesterSlashing(ctx, s, attesterSlashing)
 		_ = err
@@ -255,7 +256,7 @@ func TestFuzzProcessAttestations_10000(t *testing.T) {
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(b)
-		s, err := stateTrie.InitializeFromProtoUnsafe(state)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
 		require.NoError(t, err)
 		r, err := ProcessAttestations(ctx, s, b)
 		if err != nil && r != nil {
@@ -272,7 +273,7 @@ func TestFuzzProcessAttestationsNoVerify_10000(t *testing.T) {
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(b)
-		s, err := stateTrie.InitializeFromProtoUnsafe(state)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
 		require.NoError(t, err)
 		r, err := ProcessAttestationsNoVerifySignature(ctx, s, b)
 		if err != nil && r != nil {
@@ -289,7 +290,7 @@ func TestFuzzProcessAttestation_10000(t *testing.T) {
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(attestation)
-		s, err := stateTrie.InitializeFromProtoUnsafe(state)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
 		require.NoError(t, err)
 		r, err := ProcessAttestation(ctx, s, attestation)
 		if err != nil && r != nil {
@@ -306,7 +307,7 @@ func TestFuzzVerifyIndexedAttestationn_10000(t *testing.T) {
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(idxAttestation)
-		s, err := stateTrie.InitializeFromProtoUnsafe(state)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
 		require.NoError(t, err)
 		err = VerifyIndexedAttestation(ctx, s, idxAttestation)
 		_ = err
@@ -321,7 +322,7 @@ func TestFuzzVerifyAttestation_10000(t *testing.T) {
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(attestation)
-		s, err := stateTrie.InitializeFromProtoUnsafe(state)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
 		require.NoError(t, err)
 		err = VerifyAttestationSignature(ctx, s, attestation)
 		_ = err
@@ -331,16 +332,18 @@ func TestFuzzVerifyAttestation_10000(t *testing.T) {
 func TestFuzzProcessDeposits_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
 	state := &pb.BeaconState{}
-	b := &eth.SignedBeaconBlock{}
+	deposits := make([]*eth.Deposit, 100)
 	ctx := context.Background()
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
-		fuzzer.Fuzz(b)
-		s, err := stateTrie.InitializeFromProtoUnsafe(state)
+		for i := range deposits {
+			fuzzer.Fuzz(deposits[i])
+		}
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
 		require.NoError(t, err)
-		r, err := ProcessDeposits(ctx, s, b)
+		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, b)
+			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and block: %v", r, err, state, deposits)
 		}
 	}
 }
@@ -354,7 +357,7 @@ func TestFuzzProcessPreGenesisDeposit_10000(t *testing.T) {
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(deposit)
-		s, err := stateTrie.InitializeFromProtoUnsafe(state)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
 		require.NoError(t, err)
 		r, err := ProcessPreGenesisDeposits(ctx, s, []*eth.Deposit{deposit})
 		if err != nil && r != nil {
@@ -371,7 +374,7 @@ func TestFuzzProcessDeposit_10000(t *testing.T) {
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(deposit)
-		s, err := stateTrie.InitializeFromProtoUnsafe(state)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
 		require.NoError(t, err)
 		r, err := ProcessDeposit(s, deposit, true)
 		if err != nil && r != nil {
@@ -387,7 +390,7 @@ func TestFuzzverifyDeposit_10000(t *testing.T) {
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
 		fuzzer.Fuzz(deposit)
-		s, err := stateTrie.InitializeFromProtoUnsafe(state)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
 		require.NoError(t, err)
 		err = verifyDeposit(s, deposit)
 		_ = err
@@ -397,16 +400,16 @@ func TestFuzzverifyDeposit_10000(t *testing.T) {
 func TestFuzzProcessVoluntaryExits_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
 	state := &pb.BeaconState{}
-	b := &eth.SignedBeaconBlock{}
+	e := &eth.SignedVoluntaryExit{}
 	ctx := context.Background()
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
-		fuzzer.Fuzz(b)
-		s, err := stateTrie.InitializeFromProtoUnsafe(state)
+		fuzzer.Fuzz(e)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
 		require.NoError(t, err)
-		r, err := ProcessVoluntaryExits(ctx, s, b)
+		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, b)
+			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and exit: %v", r, err, state, e)
 		}
 	}
 }
@@ -414,15 +417,15 @@ func TestFuzzProcessVoluntaryExits_10000(t *testing.T) {
 func TestFuzzProcessVoluntaryExitsNoVerify_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
 	state := &pb.BeaconState{}
-	b := &eth.SignedBeaconBlock{}
+	e := &eth.SignedVoluntaryExit{}
 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(state)
-		fuzzer.Fuzz(b)
-		s, err := stateTrie.InitializeFromProtoUnsafe(state)
+		fuzzer.Fuzz(e)
+		s, err := stateV0.InitializeFromProtoUnsafe(state)
 		require.NoError(t, err)
-		r, err := ProcessVoluntaryExits(context.Background(), s, b)
+		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, b)
+			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and block: %v", r, err, state, e)
 		}
 	}
 }
@@ -430,7 +433,7 @@ func TestFuzzProcessVoluntaryExitsNoVerify_10000(t *testing.T) {
 func TestFuzzVerifyExit_10000(t *testing.T) {
 	fuzzer := fuzz.NewWithSeed(0)
 	ve := &eth.SignedVoluntaryExit{}
-	val := stateTrie.ReadOnlyValidator{}
+	val := stateV0.ReadOnlyValidator{}
 	fork := &pb.Fork{}
 	var slot types.Slot

--- a/beacon-chain/core/blocks/block_regression_test.go
+++ b/beacon-chain/core/blocks/block_regression_test.go
@@ -8,6 +8,7 @@ import (
 	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"
@@ -90,7 +91,7 @@ func TestProcessAttesterSlashings_RegressionSlashableIndices(t *testing.T) {
 		},
 	}

-	newState, err := blocks.ProcessAttesterSlashings(context.Background(), beaconState, b)
+	newState, err := blocks.ProcessAttesterSlashings(context.Background(), beaconState, b.Block.Body.AttesterSlashings, v.SlashValidator)
 	require.NoError(t, err)
 	newRegistry := newState.Validators()
 	if !newRegistry[expectedSlashedVal].Slashed {
--- a/beacon-chain/core/blocks/deposit.go
+++ b/beacon-chain/core/blocks/deposit.go
@@ -7,7 +7,7 @@ import (
 	"github.com/pkg/errors"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"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"
 	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
 	"github.com/prysmaticlabs/prysm/shared/bls"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
@@ -20,15 +20,23 @@ import (
 // ProcessPreGenesisDeposits processes a deposit for the beacon state before chainstart.
 func ProcessPreGenesisDeposits(
 	ctx context.Context,
-	beaconState *stateTrie.BeaconState,
+	beaconState iface.BeaconState,
 	deposits []*ethpb.Deposit,
-) (*stateTrie.BeaconState, error) {
+) (iface.BeaconState, error) {
 	var err error
-	beaconState, err = ProcessDeposits(ctx, beaconState, &ethpb.SignedBeaconBlock{
-		Block: &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{Deposits: deposits}}})
+	beaconState, err = ProcessDeposits(ctx, beaconState, deposits)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not process deposit")
 	}
+	beaconState, err = activateValidatorWithEffectiveBalance(beaconState, deposits)
+	if err != nil {
+		return nil, err
+	}
+	return beaconState, nil
+}
+
+// This updates validator's effective balance, and if it's above MaxEffectiveBalance, validator becomes active in genesis.
+func activateValidatorWithEffectiveBalance(beaconState iface.BeaconState, deposits []*ethpb.Deposit) (iface.BeaconState, error) {
 	for _, deposit := range deposits {
 		pubkey := deposit.Data.PublicKey
 		index, ok := beaconState.ValidatorIndexByPubkey(bytesutil.ToBytes48(pubkey))
@@ -67,33 +75,21 @@ func ProcessPreGenesisDeposits(
 //     process_deposit(state, deposit)
 func ProcessDeposits(
 	ctx context.Context,
-	beaconState *stateTrie.BeaconState,
-	b *ethpb.SignedBeaconBlock,
-) (*stateTrie.BeaconState, error) {
-	if err := helpers.VerifyNilBeaconBlock(b); err != nil {
-		return nil, err
-	}
-
-	deposits := b.Block.Body.Deposits
-	var err error
-	domain, err := helpers.ComputeDomain(params.BeaconConfig().DomainDeposit, nil, nil)
-	if err != nil {
-		return nil, err
-	}
-
+	beaconState iface.BeaconState,
+	deposits []*ethpb.Deposit,
+) (iface.BeaconState, error) {
 	// Attempt to verify all deposit signatures at once, if this fails then fall back to processing
 	// individual deposits with signature verification enabled.
-	var verifySignature bool
-	if err := verifyDepositDataWithDomain(ctx, deposits, domain); err != nil {
-		log.WithError(err).Debug("Failed to verify deposit data, verifying signatures individually")
-		verifySignature = true
+	batchVerified, err := batchVerifyDepositsSignatures(ctx, deposits)
+	if err != nil {
+		return nil, err
 	}

 	for _, deposit := range deposits {
 		if deposit == nil || deposit.Data == nil {
 			return nil, errors.New("got a nil deposit in block")
 		}
-		beaconState, err = ProcessDeposit(beaconState, deposit, verifySignature)
+		beaconState, err = ProcessDeposit(beaconState, deposit, batchVerified)
 		if err != nil {
 			return nil, errors.Wrapf(err, "could not process deposit from %#x", bytesutil.Trunc(deposit.Data.PublicKey))
 		}
@@ -101,6 +97,21 @@ func ProcessDeposits(
 	return beaconState, nil
 }

+func batchVerifyDepositsSignatures(ctx context.Context, deposits []*ethpb.Deposit) (bool, error) {
+	var err error
+	domain, err := helpers.ComputeDomain(params.BeaconConfig().DomainDeposit, nil, nil)
+	if err != nil {
+		return false, err
+	}
+
+	verified := false
+	if err := verifyDepositDataWithDomain(ctx, deposits, domain); err != nil {
+		log.WithError(err).Debug("Failed to batch verify deposits signatures, will try individual verify")
+		verified = true
+	}
+	return verified, nil
+}
+
 // ProcessDeposit takes in a deposit object and inserts it
 // into the registry as a new validator or balance change.
 //
@@ -140,7 +151,7 @@ func ProcessDeposits(
 //        # Increase balance by deposit amount
 //        index = ValidatorIndex(validator_pubkeys.index(pubkey))
 //        increase_balance(state, index, amount)
-func ProcessDeposit(beaconState *stateTrie.BeaconState, deposit *ethpb.Deposit, verifySignature bool) (*stateTrie.BeaconState, error) {
+func ProcessDeposit(beaconState iface.BeaconState, deposit *ethpb.Deposit, verifySignature bool) (iface.BeaconState, error) {
 	if err := verifyDeposit(beaconState, deposit); err != nil {
 		if deposit == nil || deposit.Data == nil {
 			return nil, err
@@ -191,7 +202,7 @@ func ProcessDeposit(beaconState *stateTrie.BeaconState, deposit *ethpb.Deposit,
 	return beaconState, nil
 }

-func verifyDeposit(beaconState *stateTrie.BeaconState, deposit *ethpb.Deposit) error {
+func verifyDeposit(beaconState iface.ReadOnlyBeaconState, deposit *ethpb.Deposit) error {
 	// Verify Merkle proof of deposit and deposit trie root.
 	if deposit == nil || deposit.Data == nil {
 		return errors.New("received nil deposit or nil deposit data")
--- a/beacon-chain/core/blocks/deposit_test.go
+++ b/beacon-chain/core/blocks/deposit_test.go
@@ -8,7 +8,7 @@ import (
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	"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"
@@ -40,7 +40,7 @@ func TestProcessDeposits_SameValidatorMultipleDepositsSameBlock(t *testing.T) {
 		},
 	}
 	balances := []uint64{0}
-	beaconState, err := stateTrie.InitializeFromProto(&pb.BeaconState{
+	beaconState, err := stateV0.InitializeFromProto(&pb.BeaconState{
 		Validators: registry,
 		Balances:   balances,
 		Eth1Data:   eth1Data,
@@ -50,7 +50,7 @@ func TestProcessDeposits_SameValidatorMultipleDepositsSameBlock(t *testing.T) {
 		},
 	})
 	require.NoError(t, err)
-	newState, err := blocks.ProcessDeposits(context.Background(), beaconState, b)
+	newState, err := blocks.ProcessDeposits(context.Background(), beaconState, b.Block.Body.Deposits)
 	require.NoError(t, err, "Expected block deposits to process correctly")

 	assert.Equal(t, 2, len(newState.Validators()), "Incorrect validator count")
@@ -80,7 +80,7 @@ func TestProcessDeposits_MerkleBranchFailsVerification(t *testing.T) {
 			Deposits: []*ethpb.Deposit{deposit},
 		},
 	}
-	beaconState, err := stateTrie.InitializeFromProto(&pb.BeaconState{
+	beaconState, err := stateV0.InitializeFromProto(&pb.BeaconState{
 		Eth1Data: &ethpb.Eth1Data{
 			DepositRoot: []byte{0},
 			BlockHash:   []byte{1},
@@ -88,7 +88,7 @@ func TestProcessDeposits_MerkleBranchFailsVerification(t *testing.T) {
 	})
 	require.NoError(t, err)
 	want := "deposit root did not verify"
-	_, err = blocks.ProcessDeposits(context.Background(), beaconState, b)
+	_, err = blocks.ProcessDeposits(context.Background(), beaconState, b.Block.Body.Deposits)
 	assert.ErrorContains(t, want, err)
 }

@@ -111,7 +111,7 @@ func TestProcessDeposits_AddsNewValidatorDeposit(t *testing.T) {
 		},
 	}
 	balances := []uint64{0}
-	beaconState, err := stateTrie.InitializeFromProto(&pb.BeaconState{
+	beaconState, err := stateV0.InitializeFromProto(&pb.BeaconState{
 		Validators: registry,
 		Balances:   balances,
 		Eth1Data:   eth1Data,
@@ -121,7 +121,7 @@ func TestProcessDeposits_AddsNewValidatorDeposit(t *testing.T) {
 		},
 	})
 	require.NoError(t, err)
-	newState, err := blocks.ProcessDeposits(context.Background(), beaconState, b)
+	newState, err := blocks.ProcessDeposits(context.Background(), beaconState, b.Block.Body.Deposits)
 	require.NoError(t, err, "Expected block deposits to process correctly")
 	if newState.Balances()[1] != dep[0].Data.Amount {
 		t.Errorf(
@@ -174,7 +174,7 @@ func TestProcessDeposits_RepeatedDeposit_IncreasesValidatorBalance(t *testing.T)
 	}
 	balances := []uint64{0, 50}
 	root := depositTrie.Root()
-	beaconState, err := stateTrie.InitializeFromProto(&pb.BeaconState{
+	beaconState, err := stateV0.InitializeFromProto(&pb.BeaconState{
 		Validators: registry,
 		Balances:   balances,
 		Eth1Data: &ethpb.Eth1Data{
@@ -183,7 +183,7 @@ func TestProcessDeposits_RepeatedDeposit_IncreasesValidatorBalance(t *testing.T)
 		},
 	})
 	require.NoError(t, err)
-	newState, err := blocks.ProcessDeposits(context.Background(), beaconState, b)
+	newState, err := blocks.ProcessDeposits(context.Background(), beaconState, b.Block.Body.Deposits)
 	require.NoError(t, err, "Process deposit failed")
 	assert.Equal(t, uint64(1000+50), newState.Balances()[1], "Expected balance at index 1 to be 1050")
 }
@@ -202,7 +202,7 @@ func TestProcessDeposit_AddsNewValidatorDeposit(t *testing.T) {
 		},
 	}
 	balances := []uint64{0}
-	beaconState, err := stateTrie.InitializeFromProto(&pb.BeaconState{
+	beaconState, err := stateV0.InitializeFromProto(&pb.BeaconState{
 		Validators: registry,
 		Balances:   balances,
 		Eth1Data:   eth1Data,
@@ -244,7 +244,7 @@ func TestProcessDeposit_SkipsInvalidDeposit(t *testing.T) {
 		},
 	}
 	balances := []uint64{0}
-	beaconState, err := stateTrie.InitializeFromProto(&pb.BeaconState{
+	beaconState, err := stateV0.InitializeFromProto(&pb.BeaconState{
 		Validators: registry,
 		Balances:   balances,
 		Eth1Data:   eth1Data,
@@ -300,7 +300,7 @@ func TestPreGenesisDeposits_SkipInvalidDeposit(t *testing.T) {
 		},
 	}
 	balances := []uint64{0}
-	beaconState, err := stateTrie.InitializeFromProto(&pb.BeaconState{
+	beaconState, err := stateV0.InitializeFromProto(&pb.BeaconState{
 		Validators: registry,
 		Balances:   balances,
 		Eth1Data:   eth1Data,
--- a/beacon-chain/core/blocks/eth1_data.go
+++ b/beacon-chain/core/blocks/eth1_data.go
@@ -6,7 +6,8 @@ import (
 	"errors"

 	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"
 	"github.com/prysmaticlabs/prysm/shared/params"
 )

@@ -18,24 +19,20 @@ import (
 //   def process_eth1_data(state: BeaconState, body: BeaconBlockBody) -> None:
 //    state.eth1_data_votes.append(body.eth1_data)
 //    if state.eth1_data_votes.count(body.eth1_data) * 2 > EPOCHS_PER_ETH1_VOTING_PERIOD * SLOTS_PER_EPOCH:
-//        state.latest_eth1_data = body.eth1_data
-func ProcessEth1DataInBlock(_ context.Context, beaconState *stateTrie.BeaconState, b *ethpb.SignedBeaconBlock) (*stateTrie.BeaconState, error) {
-	block := b.Block
-	if beaconState == nil {
+//        state.eth1_data = body.eth1_data
+func ProcessEth1DataInBlock(_ context.Context, beaconState iface.BeaconState, eth1Data *ethpb.Eth1Data) (iface.BeaconState, error) {
+	if beaconState == nil || beaconState.IsNil() {
 		return nil, errors.New("nil state")
 	}
-	if block == nil || block.Body == nil {
-		return nil, errors.New("nil block or block withought body")
-	}
-	if err := beaconState.AppendEth1DataVotes(block.Body.Eth1Data); err != nil {
+	if err := beaconState.AppendEth1DataVotes(eth1Data); err != nil {
 		return nil, err
 	}
-	hasSupport, err := Eth1DataHasEnoughSupport(beaconState, block.Body.Eth1Data)
+	hasSupport, err := Eth1DataHasEnoughSupport(beaconState, eth1Data)
 	if err != nil {
 		return nil, err
 	}
 	if hasSupport {
-		if err := beaconState.SetEth1Data(block.Body.Eth1Data); err != nil {
+		if err := beaconState.SetEth1Data(eth1Data); err != nil {
 			return nil, err
 		}
 	}
@@ -59,9 +56,9 @@ func AreEth1DataEqual(a, b *ethpb.Eth1Data) bool {
 // eth1 voting period. A vote is cast by including eth1data in a block and part of state processing
 // appends eth1data to the state in the Eth1DataVotes list. Iterating through this list checks the
 // votes to see if they match the eth1data.
-func Eth1DataHasEnoughSupport(beaconState *stateTrie.BeaconState, data *ethpb.Eth1Data) (bool, error) {
+func Eth1DataHasEnoughSupport(beaconState iface.ReadOnlyBeaconState, data *ethpb.Eth1Data) (bool, error) {
 	voteCount := uint64(0)
-	data = stateTrie.CopyETH1Data(data)
+	data = stateV0.CopyETH1Data(data)

 	for _, vote := range beaconState.Eth1DataVotes() {
 		if AreEth1DataEqual(vote, data) {
--- a/beacon-chain/core/blocks/eth1_data_test.go
+++ b/beacon-chain/core/blocks/eth1_data_test.go
@@ -5,17 +5,17 @@ import (
 	"fmt"
 	"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/blocks"
-	beaconstate "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	"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"
+	"google.golang.org/protobuf/proto"
 )

 func FakeDeposits(n uint64) []*ethpb.Eth1Data {
@@ -70,7 +70,7 @@ func TestEth1DataHasEnoughSupport(t *testing.T) {
 			c.EpochsPerEth1VotingPeriod = tt.votingPeriodLength
 			params.OverrideBeaconConfig(c)

-			s, err := beaconstate.InitializeFromProto(&pb.BeaconState{
+			s, err := stateV0.InitializeFromProto(&pb.BeaconState{
 				Eth1DataVotes: tt.stateVotes,
 			})
 			require.NoError(t, err)
@@ -160,7 +160,7 @@ func TestAreEth1DataEqual(t *testing.T) {
 }

 func TestProcessEth1Data_SetsCorrectly(t *testing.T) {
-	beaconState, err := beaconstate.InitializeFromProto(&pb.BeaconState{
+	beaconState, err := stateV0.InitializeFromProto(&pb.BeaconState{
 		Eth1DataVotes: []*ethpb.Eth1Data{},
 	})
 	require.NoError(t, err)
@@ -176,16 +176,19 @@ func TestProcessEth1Data_SetsCorrectly(t *testing.T) {
 	}

 	period := uint64(params.BeaconConfig().SlotsPerEpoch.Mul(uint64(params.BeaconConfig().EpochsPerEth1VotingPeriod)))
+	var ok bool
 	for i := uint64(0); i < period; i++ {
-		beaconState, err = blocks.ProcessEth1DataInBlock(context.Background(), beaconState, b)
+		processedState, err := blocks.ProcessEth1DataInBlock(context.Background(), beaconState, b.Block.Body.Eth1Data)
 		require.NoError(t, err)
+		beaconState, ok = processedState.(*stateV0.BeaconState)
+		require.Equal(t, true, ok)
 	}

 	newETH1DataVotes := beaconState.Eth1DataVotes()
 	if len(newETH1DataVotes) <= 1 {
 		t.Error("Expected new ETH1 data votes to have length > 1")
 	}
-	if !proto.Equal(beaconState.Eth1Data(), beaconstate.CopyETH1Data(b.Block.Body.Eth1Data)) {
+	if !proto.Equal(beaconState.Eth1Data(), stateV0.CopyETH1Data(b.Block.Body.Eth1Data)) {
 		t.Errorf(
 			"Expected latest eth1 data to have been set to %v, received %v",
 			b.Block.Body.Eth1Data,
--- a/beacon-chain/core/blocks/exit.go
+++ b/beacon-chain/core/blocks/exit.go
@@ -9,7 +9,6 @@ import (
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	v "github.com/prysmaticlabs/prysm/beacon-chain/core/validators"
-	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/params"
@@ -27,35 +26,28 @@ var ValidatorCannotExitYetMsg = "validator has not been active long enough to ex
 // should exit the state's validator registry.
 //
 // Spec pseudocode definition:
-//   def process_voluntary_exit(state: BeaconState, exit: VoluntaryExit) -> None:
-//    """
-//    Process ``VoluntaryExit`` operation.
-//    """
-//    validator = state.validator_registry[exit.validator_index]
+//   def process_voluntary_exit(state: BeaconState, signed_voluntary_exit: SignedVoluntaryExit) -> None:
+//    voluntary_exit = signed_voluntary_exit.message
+//    validator = state.validators[voluntary_exit.validator_index]
 //    # Verify the validator is active
 //    assert is_active_validator(validator, get_current_epoch(state))
-//    # Verify the validator has not yet exited
+//    # Verify exit has not been initiated
 //    assert validator.exit_epoch == FAR_FUTURE_EPOCH
 //    # Exits must specify an epoch when they become valid; they are not valid before then
-//    assert get_current_epoch(state) >= exit.epoch
+//    assert get_current_epoch(state) >= voluntary_exit.epoch
 //    # Verify the validator has been active long enough
-//    assert get_current_epoch(state) >= validator.activation_epoch + PERSISTENT_COMMITTEE_PERIOD
+//    assert get_current_epoch(state) >= validator.activation_epoch + SHARD_COMMITTEE_PERIOD
 //    # Verify signature
-//    domain = get_domain(state, DOMAIN_VOLUNTARY_EXIT, exit.epoch)
-//    assert bls_verify(validator.pubkey, signing_root(exit), exit.signature, domain)
+//    domain = get_domain(state, DOMAIN_VOLUNTARY_EXIT, voluntary_exit.epoch)
+//    signing_root = compute_signing_root(voluntary_exit, domain)
+//    assert bls.Verify(validator.pubkey, signing_root, signed_voluntary_exit.signature)
 //    # Initiate exit
-//    initiate_validator_exit(state, exit.validator_index)
+//    initiate_validator_exit(state, voluntary_exit.validator_index)
 func ProcessVoluntaryExits(
 	_ context.Context,
-	beaconState *stateTrie.BeaconState,
-	b *ethpb.SignedBeaconBlock,
-) (*stateTrie.BeaconState, error) {
-	if err := helpers.VerifyNilBeaconBlock(b); err != nil {
-		return nil, err
-	}
-
-	body := b.Block.Body
-	exits := body.VoluntaryExits
+	beaconState iface.BeaconState,
+	exits []*ethpb.SignedVoluntaryExit,
+) (iface.BeaconState, error) {
 	for idx, exit := range exits {
 		if exit == nil || exit.Exit == nil {
 			return nil, errors.New("nil voluntary exit in block body")
@@ -78,23 +70,30 @@ func ProcessVoluntaryExits(
 // VerifyExitAndSignature implements the spec defined validation for voluntary exits.
 //
 // Spec pseudocode definition:
-//   def process_voluntary_exit(state: BeaconState, exit: VoluntaryExit) -> None:
-//    """
-//    Process ``VoluntaryExit`` operation.
-//    """
-//    validator = state.validator_registry[exit.validator_index]
+//   def process_voluntary_exit(state: BeaconState, signed_voluntary_exit: SignedVoluntaryExit) -> None:
+//    voluntary_exit = signed_voluntary_exit.message
+//    validator = state.validators[voluntary_exit.validator_index]
 //    # Verify the validator is active
 //    assert is_active_validator(validator, get_current_epoch(state))
-//    # Verify the validator has not yet exited
+//    # Verify exit has not been initiated
 //    assert validator.exit_epoch == FAR_FUTURE_EPOCH
 //    # Exits must specify an epoch when they become valid; they are not valid before then
-//    assert get_current_epoch(state) >= exit.epoch
+//    assert get_current_epoch(state) >= voluntary_exit.epoch
 //    # Verify the validator has been active long enough
-//    assert get_current_epoch(state) >= validator.activation_epoch + PERSISTENT_COMMITTEE_PERIOD
+//    assert get_current_epoch(state) >= validator.activation_epoch + SHARD_COMMITTEE_PERIOD
 //    # Verify signature
-//    domain = get_domain(state, DOMAIN_VOLUNTARY_EXIT, exit.epoch)
-//    assert bls_verify(validator.pubkey, signing_root(exit), exit.signature, domain)
-func VerifyExitAndSignature(validator iface.ReadOnlyValidator, currentSlot types.Slot, fork *pb.Fork, signed *ethpb.SignedVoluntaryExit, genesisRoot []byte) error {
+//    domain = get_domain(state, DOMAIN_VOLUNTARY_EXIT, voluntary_exit.epoch)
+//    signing_root = compute_signing_root(voluntary_exit, domain)
+//    assert bls.Verify(validator.pubkey, signing_root, signed_voluntary_exit.signature)
+//    # Initiate exit
+//    initiate_validator_exit(state, voluntary_exit.validator_index)
+func VerifyExitAndSignature(
+	validator iface.ReadOnlyValidator,
+	currentSlot types.Slot,
+	fork *pb.Fork,
+	signed *ethpb.SignedVoluntaryExit,
+	genesisRoot []byte,
+) error {
 	if signed == nil || signed.Exit == nil {
 		return errors.New("nil exit")
 	}
@@ -117,19 +116,23 @@ func VerifyExitAndSignature(validator iface.ReadOnlyValidator, currentSlot types
 // verifyExitConditions implements the spec defined validation for voluntary exits(excluding signatures).
 //
 // Spec pseudocode definition:
-//   def process_voluntary_exit(state: BeaconState, exit: VoluntaryExit) -> None:
-//    """
-//    Process ``VoluntaryExit`` operation.
-//    """
-//    validator = state.validator_registry[exit.validator_index]
+//   def process_voluntary_exit(state: BeaconState, signed_voluntary_exit: SignedVoluntaryExit) -> None:
+//    voluntary_exit = signed_voluntary_exit.message
+//    validator = state.validators[voluntary_exit.validator_index]
 //    # Verify the validator is active
 //    assert is_active_validator(validator, get_current_epoch(state))
-//    # Verify the validator has not yet exited
+//    # Verify exit has not been initiated
 //    assert validator.exit_epoch == FAR_FUTURE_EPOCH
 //    # Exits must specify an epoch when they become valid; they are not valid before then
-//    assert get_current_epoch(state) >= exit.epoch
+//    assert get_current_epoch(state) >= voluntary_exit.epoch
 //    # Verify the validator has been active long enough
 //    assert get_current_epoch(state) >= validator.activation_epoch + SHARD_COMMITTEE_PERIOD
+//    # Verify signature
+//    domain = get_domain(state, DOMAIN_VOLUNTARY_EXIT, voluntary_exit.epoch)
+//    signing_root = compute_signing_root(voluntary_exit, domain)
+//    assert bls.Verify(validator.pubkey, signing_root, signed_voluntary_exit.signature)
+//    # Initiate exit
+//    initiate_validator_exit(state, voluntary_exit.validator_index)
 func verifyExitConditions(validator iface.ReadOnlyValidator, currentSlot types.Slot, exit *ethpb.VoluntaryExit) error {
 	currentEpoch := helpers.SlotToEpoch(currentSlot)
 	// Verify the validator is active.
@@ -147,9 +150,10 @@ func verifyExitConditions(validator iface.ReadOnlyValidator, currentSlot types.S
 	// Verify the validator has been active long enough.
 	if currentEpoch < validator.ActivationEpoch()+params.BeaconConfig().ShardCommitteePeriod {
 		return fmt.Errorf(
-			"%s: %d epochs vs required %d epochs",
+			"%s: %d of %d epochs. Validator will be eligible for exit at epoch %d",
 			ValidatorCannotExitYetMsg,
-			currentEpoch,
+			currentEpoch-validator.ActivationEpoch(),
+			params.BeaconConfig().ShardCommitteePeriod,
 			validator.ActivationEpoch()+params.BeaconConfig().ShardCommitteePeriod,
 		)
 	}
--- a/beacon-chain/core/blocks/exit_test.go
+++ b/beacon-chain/core/blocks/exit_test.go
@@ -8,7 +8,7 @@ import (
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	"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/params"
@@ -31,7 +31,7 @@ func TestProcessVoluntaryExits_NotActiveLongEnoughToExit(t *testing.T) {
 			ExitEpoch: params.BeaconConfig().FarFutureEpoch,
 		},
 	}
-	state, err := stateTrie.InitializeFromProto(&pb.BeaconState{
+	state, err := stateV0.InitializeFromProto(&pb.BeaconState{
 		Validators: registry,
 		Slot:       10,
 	})
@@ -44,7 +44,7 @@ func TestProcessVoluntaryExits_NotActiveLongEnoughToExit(t *testing.T) {
 	}

 	want := "validator has not been active long enough to exit"
-	_, err = blocks.ProcessVoluntaryExits(context.Background(), state, b)
+	_, err = blocks.ProcessVoluntaryExits(context.Background(), state, b.Block.Body.VoluntaryExits)
 	assert.ErrorContains(t, want, err)
 }

@@ -61,7 +61,7 @@ func TestProcessVoluntaryExits_ExitAlreadySubmitted(t *testing.T) {
 			ExitEpoch: 10,
 		},
 	}
-	state, err := stateTrie.InitializeFromProto(&pb.BeaconState{
+	state, err := stateV0.InitializeFromProto(&pb.BeaconState{
 		Validators: registry,
 		Slot:       0,
 	})
@@ -74,7 +74,7 @@ func TestProcessVoluntaryExits_ExitAlreadySubmitted(t *testing.T) {
 	}

 	want := "validator with index 0 has already submitted an exit, which will take place at epoch: 10"
-	_, err = blocks.ProcessVoluntaryExits(context.Background(), state, b)
+	_, err = blocks.ProcessVoluntaryExits(context.Background(), state, b.Block.Body.VoluntaryExits)
 	assert.ErrorContains(t, want, err)
 }

@@ -93,7 +93,7 @@ func TestProcessVoluntaryExits_AppliesCorrectStatus(t *testing.T) {
 			ActivationEpoch: 0,
 		},
 	}
-	state, err := stateTrie.InitializeFromProto(&pb.BeaconState{
+	state, err := stateV0.InitializeFromProto(&pb.BeaconState{
 		Validators: registry,
 		Fork: &pb.Fork{
 			CurrentVersion:  params.BeaconConfig().GenesisForkVersion,
@@ -122,7 +122,7 @@ func TestProcessVoluntaryExits_AppliesCorrectStatus(t *testing.T) {
 		},
 	}

-	newState, err := blocks.ProcessVoluntaryExits(context.Background(), state, b)
+	newState, err := blocks.ProcessVoluntaryExits(context.Background(), state, b.Block.Body.VoluntaryExits)
 	require.NoError(t, err, "Could not process exits")
 	newRegistry := newState.Validators()
 	if newRegistry[0].ExitEpoch != helpers.ActivationExitEpoch(types.Epoch(state.Slot()/params.BeaconConfig().SlotsPerEpoch)) {
--- a/beacon-chain/core/blocks/header.go
+++ b/beacon-chain/core/blocks/header.go
@@ -5,10 +5,10 @@ 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"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
 	"github.com/prysmaticlabs/prysm/shared/params"
 )

@@ -19,35 +19,43 @@ import (
 //  def process_block_header(state: BeaconState, block: BeaconBlock) -> None:
 //    # Verify that the slots match
 //    assert block.slot == state.slot
-//     # Verify that proposer index is the correct index
+//    # Verify that the block is newer than latest block header
+//    assert block.slot > state.latest_block_header.slot
+//    # Verify that proposer index is the correct index
 //    assert block.proposer_index == get_beacon_proposer_index(state)
 //    # Verify that the parent matches
 //    assert block.parent_root == hash_tree_root(state.latest_block_header)
-//    # Save current block as the new latest block
+//    # Cache current block as the new latest block
 //    state.latest_block_header = BeaconBlockHeader(
 //        slot=block.slot,
+//        proposer_index=block.proposer_index,
 //        parent_root=block.parent_root,
-//        # state_root: zeroed, overwritten in the next `process_slot` call
+//        state_root=Bytes32(),  # Overwritten in the next process_slot call
 //        body_root=hash_tree_root(block.body),
-//		  # signature is always zeroed
 //    )
+//
 //    # Verify proposer is not slashed
-//    proposer = state.validators[get_beacon_proposer_index(state)]
+//    proposer = state.validators[block.proposer_index]
 //    assert not proposer.slashed
-//    # Verify proposer signature
-//    assert bls_verify(proposer.pubkey, signing_root(block), block.signature, get_domain(state, DOMAIN_BEACON_PROPOSER))
 func ProcessBlockHeader(
 	_ context.Context,
-	beaconState *stateTrie.BeaconState,
+	beaconState iface.BeaconState,
 	block *ethpb.SignedBeaconBlock,
-) (*stateTrie.BeaconState, error) {
-	beaconState, err := ProcessBlockHeaderNoVerify(beaconState, block.Block)
+) (iface.BeaconState, error) {
+	if err := helpers.VerifyNilBeaconBlock(block); err != nil {
+		return nil, err
+	}
+	bodyRoot, err := block.Block.Body.HashTreeRoot()
+	if err != nil {
+		return nil, err
+	}
+	beaconState, err = ProcessBlockHeaderNoVerify(beaconState, block.Block.Slot, block.Block.ProposerIndex, block.Block.ParentRoot, bodyRoot[:])
 	if err != nil {
 		return nil, err
 	}

 	// Verify proposer signature.
-	if err := VerifyBlockSignature(beaconState, block); err != nil {
+	if err := VerifyBlockSignature(beaconState, block.Block.ProposerIndex, block.Signature, block.Block.HashTreeRoot); err != nil {
 		return nil, err
 	}

@@ -64,51 +72,52 @@ func ProcessBlockHeader(
 //  def process_block_header(state: BeaconState, block: BeaconBlock) -> None:
 //    # Verify that the slots match
 //    assert block.slot == state.slot
-//     # Verify that proposer index is the correct index
+//    # Verify that the block is newer than latest block header
+//    assert block.slot > state.latest_block_header.slot
+//    # Verify that proposer index is the correct index
 //    assert block.proposer_index == get_beacon_proposer_index(state)
 //    # Verify that the parent matches
 //    assert block.parent_root == hash_tree_root(state.latest_block_header)
-//    # Save current block as the new latest block
+//    # Cache current block as the new latest block
 //    state.latest_block_header = BeaconBlockHeader(
 //        slot=block.slot,
+//        proposer_index=block.proposer_index,
 //        parent_root=block.parent_root,
-//        # state_root: zeroed, overwritten in the next `process_slot` call
+//        state_root=Bytes32(),  # Overwritten in the next process_slot call
 //        body_root=hash_tree_root(block.body),
-//		  # signature is always zeroed
 //    )
+//
 //    # Verify proposer is not slashed
-//    proposer = state.validators[get_beacon_proposer_index(state)]
+//    proposer = state.validators[block.proposer_index]
 //    assert not proposer.slashed
 func ProcessBlockHeaderNoVerify(
-	beaconState *stateTrie.BeaconState,
-	block *ethpb.BeaconBlock,
-) (*stateTrie.BeaconState, error) {
-	if block == nil {
-		return nil, errors.New("nil block")
-	}
-	if beaconState.Slot() != block.Slot {
-		return nil, fmt.Errorf("state slot: %d is different than block slot: %d", beaconState.Slot(), block.Slot)
+	beaconState iface.BeaconState,
+	slot types.Slot, proposerIndex types.ValidatorIndex,
+	parentRoot, bodyRoot []byte,
+) (iface.BeaconState, error) {
+	if beaconState.Slot() != slot {
+		return nil, fmt.Errorf("state slot: %d is different than block slot: %d", beaconState.Slot(), slot)
 	}
 	idx, err := helpers.BeaconProposerIndex(beaconState)
 	if err != nil {
 		return nil, err
 	}
-	if block.ProposerIndex != idx {
-		return nil, fmt.Errorf("proposer index: %d is different than calculated: %d", block.ProposerIndex, idx)
+	if proposerIndex != idx {
+		return nil, fmt.Errorf("proposer index: %d is different than calculated: %d", proposerIndex, idx)
 	}
 	parentHeader := beaconState.LatestBlockHeader()
-	if parentHeader.Slot >= block.Slot {
-		return nil, fmt.Errorf("block.Slot %d must be greater than state.LatestBlockHeader.Slot %d", block.Slot, parentHeader.Slot)
+	if parentHeader.Slot >= slot {
+		return nil, fmt.Errorf("block.Slot %d must be greater than state.LatestBlockHeader.Slot %d", slot, parentHeader.Slot)
 	}
-	parentRoot, err := parentHeader.HashTreeRoot()
+	parentHeaderRoot, err := parentHeader.HashTreeRoot()
 	if err != nil {
 		return nil, err
 	}

-	if !bytes.Equal(block.ParentRoot, parentRoot[:]) {
+	if !bytes.Equal(parentRoot, parentHeaderRoot[:]) {
 		return nil, fmt.Errorf(
 			"parent root %#x does not match the latest block header signing root in state %#x",
-			block.ParentRoot, parentRoot)
+			parentRoot, parentHeaderRoot[:])
 	}

 	proposer, err := beaconState.ValidatorAtIndexReadOnly(idx)
@@ -119,16 +128,12 @@ func ProcessBlockHeaderNoVerify(
 		return nil, fmt.Errorf("proposer at index %d was previously slashed", idx)
 	}

-	bodyRoot, err := block.Body.HashTreeRoot()
-	if err != nil {
-		return nil, err
-	}
 	if err := beaconState.SetLatestBlockHeader(&ethpb.BeaconBlockHeader{
-		Slot:          block.Slot,
-		ProposerIndex: block.ProposerIndex,
-		ParentRoot:    block.ParentRoot,
+		Slot:          slot,
+		ProposerIndex: proposerIndex,
+		ParentRoot:    parentRoot,
 		StateRoot:     params.BeaconConfig().ZeroHash[:],
-		BodyRoot:      bodyRoot[:],
+		BodyRoot:      bodyRoot,
 	}); err != nil {
 		return nil, err
 	}
--- a/beacon-chain/core/blocks/header_test.go
+++ b/beacon-chain/core/blocks/header_test.go
@@ -5,7 +5,6 @@ import (
 	"io/ioutil"
 	"testing"

-	"github.com/gogo/protobuf/proto"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
@@ -17,6 +16,7 @@ import (
 	"github.com/prysmaticlabs/prysm/shared/testutil/assert"
 	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 	"github.com/sirupsen/logrus"
+	"google.golang.org/protobuf/proto"
 )

 func init() {
@@ -125,16 +125,13 @@ func TestProcessBlockHeader_DifferentSlots(t *testing.T) {
 	blockSig, err := helpers.ComputeDomainAndSign(state, currentEpoch, &sszBytes, params.BeaconConfig().DomainBeaconProposer, priv)
 	require.NoError(t, err)
 	validators[5896].PublicKey = priv.PublicKey().Marshal()
-	block := &ethpb.SignedBeaconBlock{
+	block := testutil.HydrateSignedBeaconBlock(&ethpb.SignedBeaconBlock{
 		Block: &ethpb.BeaconBlock{
-			Slot: 1,
-			Body: &ethpb.BeaconBlockBody{
-				RandaoReveal: []byte{'A', 'B', 'C'},
-			},
+			Slot:       1,
 			ParentRoot: lbhsr[:],
 		},
 		Signature: blockSig,
-	}
+	})

 	_, err = blocks.ProcessBlockHeader(context.Background(), state, block)
 	want := "is different than block slot"
@@ -321,7 +318,7 @@ func TestBlockSignatureSet_OK(t *testing.T) {
 	validators[proposerIdx].PublicKey = priv.PublicKey().Marshal()
 	err = state.UpdateValidatorAtIndex(proposerIdx, validators[proposerIdx])
 	require.NoError(t, err)
-	set, err := blocks.BlockSignatureSet(state, block)
+	set, err := blocks.BlockSignatureSet(state, block.Block.ProposerIndex, block.Signature, block.Block.HashTreeRoot)
 	require.NoError(t, err)

 	verified, err := set.Verify()
--- a/beacon-chain/core/blocks/proposer_slashing.go
+++ b/beacon-chain/core/blocks/proposer_slashing.go
@@ -4,59 +4,57 @@ import (
 	"context"
 	"fmt"

-	"github.com/prysmaticlabs/prysm/shared/params"
-
-	"github.com/gogo/protobuf/proto"
 	"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"
-	v "github.com/prysmaticlabs/prysm/beacon-chain/core/validators"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	iface "github.com/prysmaticlabs/prysm/beacon-chain/state/interface"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"google.golang.org/protobuf/proto"
 )

+type slashValidatorFunc func(iface.BeaconState, types.ValidatorIndex) (iface.BeaconState, error)
+
 // ProcessProposerSlashings is one of the operations performed
 // on each processed beacon block to slash proposers based on
 // slashing conditions if any slashable events occurred.
 //
 // Spec pseudocode definition:
 //   def process_proposer_slashing(state: BeaconState, proposer_slashing: ProposerSlashing) -> None:
-//    """
-//    Process ``ProposerSlashing`` operation.
-//    """
-//    proposer = state.validator_registry[proposer_slashing.proposer_index]
-//    # Verify slots match
-//    assert proposer_slashing.header_1.slot == proposer_slashing.header_2.slot
-//    # But the headers are different
-//    assert proposer_slashing.header_1 != proposer_slashing.header_2
-//    # Check proposer is slashable
-//    assert is_slashable_validator(proposer, get_current_epoch(state))
-//    # Signatures are valid
-//    for header in (proposer_slashing.header_1, proposer_slashing.header_2):
-//        domain = get_domain(state, DOMAIN_BEACON_PROPOSER, slot_to_epoch(header.slot))
-//        assert bls_verify(proposer.pubkey, signing_root(header), header.signature, domain)
+//    header_1 = proposer_slashing.signed_header_1.message
+//    header_2 = proposer_slashing.signed_header_2.message
 //
-//    slash_validator(state, proposer_slashing.proposer_index)
+//    # Verify header slots match
+//    assert header_1.slot == header_2.slot
+//    # Verify header proposer indices match
+//    assert header_1.proposer_index == header_2.proposer_index
+//    # Verify the headers are different
+//    assert header_1 != header_2
+//    # Verify the proposer is slashable
+//    proposer = state.validators[header_1.proposer_index]
+//    assert is_slashable_validator(proposer, get_current_epoch(state))
+//    # Verify signatures
+//    for signed_header in (proposer_slashing.signed_header_1, proposer_slashing.signed_header_2):
+//        domain = get_domain(state, DOMAIN_BEACON_PROPOSER, compute_epoch_at_slot(signed_header.message.slot))
+//        signing_root = compute_signing_root(signed_header.message, domain)
+//        assert bls.Verify(proposer.pubkey, signing_root, signed_header.signature)
+//
+//    slash_validator(state, header_1.proposer_index)
 func ProcessProposerSlashings(
 	_ context.Context,
-	beaconState *stateTrie.BeaconState,
-	b *ethpb.SignedBeaconBlock,
-) (*stateTrie.BeaconState, error) {
-	if err := helpers.VerifyNilBeaconBlock(b); err != nil {
-		return nil, err
-	}
-
-	body := b.Block.Body
+	beaconState iface.BeaconState,
+	slashings []*ethpb.ProposerSlashing,
+	slashFunc slashValidatorFunc,
+) (iface.BeaconState, error) {
 	var err error
-	for idx, slashing := range body.ProposerSlashings {
+	for idx, slashing := range slashings {
 		if slashing == nil {
 			return nil, errors.New("nil proposer slashings in block body")
 		}
 		if err = VerifyProposerSlashing(beaconState, slashing); err != nil {
 			return nil, errors.Wrapf(err, "could not verify proposer slashing %d", idx)
 		}
-		beaconState, err = v.SlashValidator(
-			beaconState, slashing.Header_1.Header.ProposerIndex,
-		)
+		beaconState, err = slashFunc(beaconState, slashing.Header_1.Header.ProposerIndex)
 		if err != nil {
 			return nil, errors.Wrapf(err, "could not slash proposer index %d", slashing.Header_1.Header.ProposerIndex)
 		}
@@ -66,7 +64,7 @@ func ProcessProposerSlashings(

 // VerifyProposerSlashing verifies that the data provided from slashing is valid.
 func VerifyProposerSlashing(
-	beaconState *stateTrie.BeaconState,
+	beaconState iface.BeaconState,
 	slashing *ethpb.ProposerSlashing,
 ) error {
 	if slashing.Header_1 == nil || slashing.Header_1.Header == nil || slashing.Header_2 == nil || slashing.Header_2.Header == nil {
--- a/beacon-chain/core/blocks/proposer_slashing_regression_test.go
+++ b/beacon-chain/core/blocks/proposer_slashing_regression_test.go
@@ -5,9 +5,9 @@ import (
 	"testing"

 	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateV0"

 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
 	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
 	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 )
@@ -24,7 +24,7 @@ func TestVerifyProposerSlashing_BeaconFuzzIssue91(t *testing.T) {
 	err = rawState.UnmarshalSSZ(file)
 	require.NoError(t, err)

-	st, err := stateTrie.InitializeFromProtoUnsafe(rawState)
+	st, err := stateV0.InitializeFromProtoUnsafe(rawState)
 	require.NoError(t, err)

 	file, err = ioutil.ReadFile("testdata/beaconfuzz_91_proposer_slashing.ssz")
--- a/beacon-chain/core/blocks/proposer_slashing_test.go
+++ b/beacon-chain/core/blocks/proposer_slashing_test.go
@@ -9,7 +9,9 @@ import (
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
-	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	v "github.com/prysmaticlabs/prysm/beacon-chain/core/validators"
+	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/bls"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
@@ -48,7 +50,7 @@ func TestProcessProposerSlashings_UnmatchedHeaderSlots(t *testing.T) {
 		},
 	}
 	want := "mismatched header slots"
-	_, err := blocks.ProcessProposerSlashings(context.Background(), beaconState, b)
+	_, err := blocks.ProcessProposerSlashings(context.Background(), beaconState, b.Block.Body.ProposerSlashings, v.SlashValidator)
 	assert.ErrorContains(t, want, err)
 }

@@ -81,7 +83,7 @@ func TestProcessProposerSlashings_SameHeaders(t *testing.T) {
 		},
 	}
 	want := "expected slashing headers to differ"
-	_, err := blocks.ProcessProposerSlashings(context.Background(), beaconState, b)
+	_, err := blocks.ProcessProposerSlashings(context.Background(), beaconState, b.Block.Body.ProposerSlashings, v.SlashValidator)
 	assert.ErrorContains(t, want, err)
 }

@@ -116,7 +118,7 @@ func TestProcessProposerSlashings_ValidatorNotSlashable(t *testing.T) {
 		},
 	}

-	beaconState, err := stateTrie.InitializeFromProto(&pb.BeaconState{
+	beaconState, err := stateV0.InitializeFromProto(&pb.BeaconState{
 		Validators: registry,
 		Slot:       currentSlot,
 	})
@@ -131,7 +133,7 @@ func TestProcessProposerSlashings_ValidatorNotSlashable(t *testing.T) {
 		"validator with key %#x is not slashable",
 		bytesutil.ToBytes48(beaconState.Validators()[0].PublicKey),
 	)
-	_, err = blocks.ProcessProposerSlashings(context.Background(), beaconState, b)
+	_, err = blocks.ProcessProposerSlashings(context.Background(), beaconState, b.Block.Body.ProposerSlashings, v.SlashValidator)
 	assert.ErrorContains(t, want, err)
 }

@@ -170,7 +172,7 @@ func TestProcessProposerSlashings_AppliesCorrectStatus(t *testing.T) {
 	block := testutil.NewBeaconBlock()
 	block.Block.Body.ProposerSlashings = slashings

-	newState, err := blocks.ProcessProposerSlashings(context.Background(), beaconState, block)
+	newState, err := blocks.ProcessProposerSlashings(context.Background(), beaconState, block.Block.Body.ProposerSlashings, v.SlashValidator)
 	require.NoError(t, err)

 	newStateVals := newState.Validators()
@@ -182,7 +184,7 @@ func TestProcessProposerSlashings_AppliesCorrectStatus(t *testing.T) {

 func TestVerifyProposerSlashing(t *testing.T) {
 	type args struct {
-		beaconState *stateTrie.BeaconState
+		beaconState iface.BeaconState
 		slashing    *ethpb.ProposerSlashing
 	}

--- a/beacon-chain/core/blocks/randao.go
+++ b/beacon-chain/core/blocks/randao.go
@@ -6,7 +6,7 @@ import (
 	"github.com/pkg/errors"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"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/hashutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
 )
@@ -27,9 +27,9 @@ import (
 //    state.randao_mixes[epoch % EPOCHS_PER_HISTORICAL_VECTOR] = mix
 func ProcessRandao(
 	_ context.Context,
-	beaconState *stateTrie.BeaconState,
+	beaconState iface.BeaconState,
 	b *ethpb.SignedBeaconBlock,
-) (*stateTrie.BeaconState, error) {
+) (iface.BeaconState, error) {
 	if err := helpers.VerifyNilBeaconBlock(b); err != nil {
 		return nil, err
 	}
@@ -42,7 +42,7 @@ func ProcessRandao(
 		return nil, errors.Wrap(err, "could not verify block randao")
 	}

-	beaconState, err = ProcessRandaoNoVerify(beaconState, body)
+	beaconState, err = ProcessRandaoNoVerify(beaconState, body.RandaoReveal)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not process randao")
 	}
@@ -59,9 +59,9 @@ func ProcessRandao(
 //             hash(body.randao_reveal))
 //     )
 func ProcessRandaoNoVerify(
-	beaconState *stateTrie.BeaconState,
-	body *ethpb.BeaconBlockBody,
-) (*stateTrie.BeaconState, error) {
+	beaconState iface.BeaconState,
+	randaoReveal []byte,
+) (iface.BeaconState, error) {
 	currentEpoch := helpers.SlotToEpoch(beaconState.Slot())
 	// If block randao passed verification, we XOR the state's latest randao mix with the block's
 	// randao and update the state's corresponding latest randao mix value.
@@ -70,7 +70,7 @@ func ProcessRandaoNoVerify(
 	if err != nil {
 		return nil, err
 	}
-	blockRandaoReveal := hashutil.Hash(body.RandaoReveal)
+	blockRandaoReveal := hashutil.Hash(randaoReveal)
 	if len(blockRandaoReveal) != len(latestMixSlice) {
 		return nil, errors.New("blockRandaoReveal length doesnt match latestMixSlice length")
 	}
--- a/beacon-chain/core/blocks/randao_test.go
+++ b/beacon-chain/core/blocks/randao_test.go
@@ -80,7 +80,7 @@ func TestRandaoSignatureSet_OK(t *testing.T) {
 		},
 	}

-	set, err := blocks.RandaoSignatureSet(beaconState, block.Body)
+	set, err := blocks.RandaoSignatureSet(beaconState, block.Body.RandaoReveal)
 	require.NoError(t, err)
 	verified, err := set.Verify()
 	require.NoError(t, err)
--- a/beacon-chain/core/blocks/signature.go
+++ b/beacon-chain/core/blocks/signature.go
@@ -8,7 +8,7 @@ import (
 	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"
+	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"
@@ -60,45 +60,51 @@ func verifySignature(signedData, pub, signature, domain []byte) error {
 }

 // VerifyBlockSignature verifies the proposer signature of a beacon block.
-func VerifyBlockSignature(beaconState *stateTrie.BeaconState, block *ethpb.SignedBeaconBlock) error {
+func VerifyBlockSignature(beaconState iface.ReadOnlyBeaconState,
+	proposerIndex types.ValidatorIndex,
+	sig []byte,
+	rootFunc func() ([32]byte, error)) error {
 	currentEpoch := helpers.SlotToEpoch(beaconState.Slot())
 	domain, err := helpers.Domain(beaconState.Fork(), currentEpoch, params.BeaconConfig().DomainBeaconProposer, beaconState.GenesisValidatorRoot())
 	if err != nil {
 		return err
 	}
-	proposer, err := beaconState.ValidatorAtIndex(block.Block.ProposerIndex)
+	proposer, err := beaconState.ValidatorAtIndex(proposerIndex)
 	if err != nil {
 		return err
 	}
 	proposerPubKey := proposer.PublicKey
-	return helpers.VerifyBlockSigningRoot(block.Block, proposerPubKey, block.Signature, domain)
+	return helpers.VerifyBlockSigningRoot(proposerPubKey, sig, domain, rootFunc)
 }

 // BlockSignatureSet retrieves the block signature set from the provided block and its corresponding state.
-func BlockSignatureSet(beaconState *stateTrie.BeaconState, block *ethpb.SignedBeaconBlock) (*bls.SignatureSet, error) {
+func BlockSignatureSet(beaconState iface.ReadOnlyBeaconState,
+	proposerIndex types.ValidatorIndex,
+	sig []byte,
+	rootFunc func() ([32]byte, error)) (*bls.SignatureSet, error) {
 	currentEpoch := helpers.SlotToEpoch(beaconState.Slot())
 	domain, err := helpers.Domain(beaconState.Fork(), currentEpoch, params.BeaconConfig().DomainBeaconProposer, beaconState.GenesisValidatorRoot())
 	if err != nil {
 		return nil, err
 	}
-	proposer, err := beaconState.ValidatorAtIndex(block.Block.ProposerIndex)
+	proposer, err := beaconState.ValidatorAtIndex(proposerIndex)
 	if err != nil {
 		return nil, err
 	}
 	proposerPubKey := proposer.PublicKey
-	return helpers.BlockSignatureSet(block.Block, proposerPubKey, block.Signature, domain)
+	return helpers.BlockSignatureSet(proposerPubKey, sig, domain, rootFunc)
 }

 // RandaoSignatureSet retrieves the relevant randao specific signature set object
 // from a block and its corresponding state.
-func RandaoSignatureSet(beaconState *stateTrie.BeaconState,
-	body *ethpb.BeaconBlockBody,
+func RandaoSignatureSet(beaconState iface.ReadOnlyBeaconState,
+	reveal []byte,
 ) (*bls.SignatureSet, error) {
 	buf, proposerPub, domain, err := randaoSigningData(beaconState)
 	if err != nil {
 		return nil, err
 	}
-	set, err := signatureSet(buf, proposerPub, body.RandaoReveal, domain)
+	set, err := signatureSet(buf, proposerPub, reveal, domain)
 	if err != nil {
 		return nil, err
 	}
@@ -106,7 +112,7 @@ func RandaoSignatureSet(beaconState *stateTrie.BeaconState,
 }

 // retrieves the randao related signing data from the state.
-func randaoSigningData(beaconState *stateTrie.BeaconState) ([]byte, []byte, []byte, error) {
+func randaoSigningData(beaconState iface.ReadOnlyBeaconState) ([]byte, []byte, []byte, error) {
 	proposerIdx, err := helpers.BeaconProposerIndex(beaconState)
 	if err != nil {
 		return nil, nil, nil, errors.Wrap(err, "could not get beacon proposer index")
@@ -125,7 +131,12 @@ func randaoSigningData(beaconState *stateTrie.BeaconState) ([]byte, []byte, []by
 }

 // Method to break down attestations of the same domain and collect them into a single signature set.
-func createAttestationSignatureSet(ctx context.Context, beaconState *stateTrie.BeaconState, atts []*ethpb.Attestation, domain []byte) (*bls.SignatureSet, error) {
+func createAttestationSignatureSet(
+	ctx context.Context,
+	beaconState iface.ReadOnlyBeaconState,
+	atts []*ethpb.Attestation,
+	domain []byte,
+) (*bls.SignatureSet, error) {
 	if len(atts) == 0 {
 		return nil, nil
 	}
@@ -173,7 +184,7 @@ func createAttestationSignatureSet(ctx context.Context, beaconState *stateTrie.B

 // AttestationSignatureSet retrieves all the related attestation signature data such as the relevant public keys,
 // signatures and attestation signing data and collate it into a signature set object.
-func AttestationSignatureSet(ctx context.Context, beaconState *stateTrie.BeaconState, atts []*ethpb.Attestation) (*bls.SignatureSet, error) {
+func AttestationSignatureSet(ctx context.Context, beaconState iface.ReadOnlyBeaconState, atts []*ethpb.Attestation) (*bls.SignatureSet, error) {
 	if len(atts) == 0 {
 		return bls.NewSet(), nil
 	}
--- a/beacon-chain/core/blocks/spectest/BUILD.bazel
+++ b/beacon-chain/core/blocks/spectest/BUILD.bazel
@@ -1,85 +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 = ["block_processing_test.yaml.go"],
-    importpath = "github.com/prysmaticlabs/prysm/beacon-chain/core/blocks/spectest",
-    visibility = ["//beacon-chain:__subpackages__"],
-)
-
-test_suite(
-    name = "go_default_test",
-    tags = ["spectest"],
-    tests = [
-        ":go_mainnet_test",
-        # Minimal tests must be run with --define ssz=minimal
-        #":go_minimal_test",
-    ],
-)
-
-go_test(
-    name = "go_mainnet_test",
-    size = "medium",
-    srcs = glob(
-        ["*_test.go"],
-        exclude = ["*_minimal_test.go"],
-    ),
-    data = glob(["*.yaml"]) + [
-        "@eth2_spec_tests_mainnet//:test_data",
-    ],
-    embed = [":go_default_library"],
-    shard_count = 4,
-    tags = ["spectest"],
-    deps = [
-        "//beacon-chain/core/blocks:go_default_library",
-        "//beacon-chain/core/helpers:go_default_library",
-        "//beacon-chain/core/state:go_default_library",
-        "//beacon-chain/core/state/stateutils:go_default_library",
-        "//beacon-chain/state:go_default_library",
-        "//proto/beacon/p2p/v1:go_default_library",
-        "//shared/params:go_default_library",
-        "//shared/params/spectest:go_default_library",
-        "//shared/testutil:go_default_library",
-        "//shared/testutil/require:go_default_library",
-        "@com_github_gogo_protobuf//proto:go_default_library",
-        "@com_github_prysmaticlabs_ethereumapis//eth/v1alpha1:go_default_library",
-        "@in_gopkg_d4l3k_messagediff_v1//:go_default_library",
-        "@io_bazel_rules_go//go/tools/bazel:go_default_library",
-    ],
-)
-
-# Requires --define ssz=minimal
-go_test(
-    name = "go_minimal_test",
-    size = "small",
-    srcs = glob(
-        ["*_test.go"],
-        exclude = ["*_mainnet_test.go"],
-    ),
-    data = glob(["*.yaml"]) + [
-        "@eth2_spec_tests_minimal//:test_data",
-    ],
-    embed = [":go_default_library"],
-    tags = [
-        "manual",
-        "minimal",
-        "spectest",
-    ],
-    deps = [
-        "//beacon-chain/core/blocks:go_default_library",
-        "//beacon-chain/core/helpers:go_default_library",
-        "//beacon-chain/core/state:go_default_library",
-        "//beacon-chain/core/state/stateutils:go_default_library",
-        "//beacon-chain/state:go_default_library",
-        "//proto/beacon/p2p/v1:go_default_library",
-        "//shared/params:go_default_library",
-        "//shared/params/spectest:go_default_library",
-        "//shared/testutil:go_default_library",
-        "//shared/testutil/require:go_default_library",
-        "@com_github_gogo_protobuf//proto:go_default_library",
-        "@com_github_prysmaticlabs_ethereumapis//eth/v1alpha1:go_default_library",
-        "@in_gopkg_d4l3k_messagediff_v1//:go_default_library",
-        "@io_bazel_rules_go//go/tools/bazel:go_default_library",
-    ],
-)
--- a/beacon-chain/core/blocks/spectest/attestation_mainnet_test.go
+++ b/beacon-chain/core/blocks/spectest/attestation_mainnet_test.go
@@ -1,9 +0,0 @@
-package spectest
-
-import (
-	"testing"
-)
-
-func TestAttestationMainnet(t *testing.T) {
-	runAttestationTest(t, "mainnet")
-}
--- a/beacon-chain/core/blocks/spectest/attestation_minimal_test.go
+++ b/beacon-chain/core/blocks/spectest/attestation_minimal_test.go
@@ -1,9 +0,0 @@
-package spectest
-
-import (
-	"testing"
-)
-
-func TestAttestationMinimal(t *testing.T) {
-	runAttestationTest(t, "minimal")
-}
--- a/beacon-chain/core/blocks/spectest/attestation_test.go
+++ b/beacon-chain/core/blocks/spectest/attestation_test.go
@@ -1,30 +0,0 @@
-package spectest
-
-import (
-	"path"
-	"testing"
-
-	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
-	"github.com/prysmaticlabs/prysm/shared/params/spectest"
-	"github.com/prysmaticlabs/prysm/shared/testutil"
-	"github.com/prysmaticlabs/prysm/shared/testutil/require"
-)
-
-func runAttestationTest(t *testing.T, config string) {
-	require.NoError(t, spectest.SetConfig(t, config))
-
-	testFolders, testsFolderPath := testutil.TestFolders(t, config, "operations/attestation/pyspec_tests")
-	for _, folder := range testFolders {
-		t.Run(folder.Name(), func(t *testing.T) {
-			folderPath := path.Join(testsFolderPath, folder.Name())
-			attestationFile, err := testutil.BazelFileBytes(folderPath, "attestation.ssz")
-			require.NoError(t, err)
-			att := &ethpb.Attestation{}
-			require.NoError(t, att.UnmarshalSSZ(attestationFile), "Failed to unmarshal")
-
-			body := &ethpb.BeaconBlockBody{Attestations: []*ethpb.Attestation{att}}
-			testutil.RunBlockOperationTest(t, folderPath, body, blocks.ProcessAttestations)
-		})
-	}
-}
--- a/beacon-chain/core/blocks/spectest/attester_slashing_mainnet_test.go
+++ b/beacon-chain/core/blocks/spectest/attester_slashing_mainnet_test.go
@@ -1,9 +0,0 @@
-package spectest
-
-import (
-	"testing"
-)
-
-func TestAttesterSlashingMainnet(t *testing.T) {
-	runAttesterSlashingTest(t, "mainnet")
-}
--- a/beacon-chain/core/blocks/spectest/attester_slashing_minimal_test.go
+++ b/beacon-chain/core/blocks/spectest/attester_slashing_minimal_test.go
@@ -1,9 +0,0 @@
-package spectest
-
-import (
-	"testing"
-)
-
-func TestAttesterSlashingMinimal(t *testing.T) {
-	runAttesterSlashingTest(t, "minimal")
-}
--- a/beacon-chain/core/blocks/spectest/attester_slashing_test.go
+++ b/beacon-chain/core/blocks/spectest/attester_slashing_test.go
@@ -1,30 +0,0 @@
-package spectest
-
-import (
-	"path"
-	"testing"
-
-	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
-	"github.com/prysmaticlabs/prysm/shared/params/spectest"
-	"github.com/prysmaticlabs/prysm/shared/testutil"
-	"github.com/prysmaticlabs/prysm/shared/testutil/require"
-)
-
-func runAttesterSlashingTest(t *testing.T, config string) {
-	require.NoError(t, spectest.SetConfig(t, config))
-
-	testFolders, testsFolderPath := testutil.TestFolders(t, config, "operations/attester_slashing/pyspec_tests")
-	for _, folder := range testFolders {
-		t.Run(folder.Name(), func(t *testing.T) {
-			folderPath := path.Join(testsFolderPath, folder.Name())
-			attSlashingFile, err := testutil.BazelFileBytes(folderPath, "attester_slashing.ssz")
-			require.NoError(t, err)
-			attSlashing := &ethpb.AttesterSlashing{}
-			require.NoError(t, attSlashing.UnmarshalSSZ(attSlashingFile), "Failed to unmarshal")
-
-			body := &ethpb.BeaconBlockBody{AttesterSlashings: []*ethpb.AttesterSlashing{attSlashing}}
-			testutil.RunBlockOperationTest(t, folderPath, body, blocks.ProcessAttesterSlashings)
-		})
-	}
-}
--- a/beacon-chain/core/blocks/spectest/block_header_mainnet_test.go
+++ b/beacon-chain/core/blocks/spectest/block_header_mainnet_test.go
@@ -1,9 +0,0 @@
-package spectest
-
-import (
-	"testing"
-)
-
-func TestBlockHeaderMainnet(t *testing.T) {
-	runBlockHeaderTest(t, "mainnet")
-}
--- a/beacon-chain/core/blocks/spectest/block_header_minimal_test.go
+++ b/beacon-chain/core/blocks/spectest/block_header_minimal_test.go
@@ -1,9 +0,0 @@
-package spectest
-
-import (
-	"testing"
-)
-
-func TestBlockHeaderMinimal(t *testing.T) {
-	runBlockHeaderTest(t, "minimal")
-}
--- a/beacon-chain/core/blocks/spectest/block_processing_mainnet_test.go
+++ b/beacon-chain/core/blocks/spectest/block_processing_mainnet_test.go
@@ -1,9 +0,0 @@
-package spectest
-
-import (
-	"testing"
-)
-
-func TestBlockProcessingMainnetYaml(t *testing.T) {
-	runBlockProcessingTest(t, "mainnet")
-}
--- a/beacon-chain/core/blocks/spectest/block_processing_minimal_test.go
+++ b/beacon-chain/core/blocks/spectest/block_processing_minimal_test.go
@@ -1,9 +0,0 @@
-package spectest
-
-import (
-	"testing"
-)
-
-func TestBlockProcessingMinimalYaml(t *testing.T) {
-	runBlockProcessingTest(t, "minimal")
-}
--- a/beacon-chain/core/blocks/spectest/deposit_mainnet_test.go
+++ b/beacon-chain/core/blocks/spectest/deposit_mainnet_test.go
@@ -1,9 +0,0 @@
-package spectest
-
-import (
-	"testing"
-)
-
-func TestDepositMainnetYaml(t *testing.T) {
-	runDepositTest(t, "mainnet")
-}
--- a/beacon-chain/core/blocks/spectest/deposit_minimal_test.go
+++ b/beacon-chain/core/blocks/spectest/deposit_minimal_test.go
@@ -1,9 +0,0 @@
-package spectest
-
-import (
-	"testing"
-)
-
-func TestDepositMinimalYaml(t *testing.T) {
-	runDepositTest(t, "minimal")
-}
--- a/beacon-chain/core/blocks/spectest/deposit_test.go
+++ b/beacon-chain/core/blocks/spectest/deposit_test.go
@@ -1,30 +0,0 @@
-package spectest
-
-import (
-	"path"
-	"testing"
-
-	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
-	"github.com/prysmaticlabs/prysm/shared/params/spectest"
-	"github.com/prysmaticlabs/prysm/shared/testutil"
-	"github.com/prysmaticlabs/prysm/shared/testutil/require"
-)
-
-func runDepositTest(t *testing.T, config string) {
-	require.NoError(t, spectest.SetConfig(t, config))
-
-	testFolders, testsFolderPath := testutil.TestFolders(t, config, "operations/deposit/pyspec_tests")
-	for _, folder := range testFolders {
-		t.Run(folder.Name(), func(t *testing.T) {
-			folderPath := path.Join(testsFolderPath, folder.Name())
-			depositFile, err := testutil.BazelFileBytes(folderPath, "deposit.ssz")
-			require.NoError(t, err)
-			deposit := &ethpb.Deposit{}
-			require.NoError(t, deposit.UnmarshalSSZ(depositFile), "Failed to unmarshal")
-
-			body := &ethpb.BeaconBlockBody{Deposits: []*ethpb.Deposit{deposit}}
-			testutil.RunBlockOperationTest(t, folderPath, body, blocks.ProcessDeposits)
-		})
-	}
-}
--- a/beacon-chain/core/blocks/spectest/proposer_slashing_mainnet_test.go
+++ b/beacon-chain/core/blocks/spectest/proposer_slashing_mainnet_test.go
@@ -1,9 +0,0 @@
-package spectest
-
-import (
-	"testing"
-)
-
-func TestProposerSlashingMainnet(t *testing.T) {
-	runProposerSlashingTest(t, "mainnet")
-}
--- a/beacon-chain/core/blocks/spectest/proposer_slashing_minimal_test.go
+++ b/beacon-chain/core/blocks/spectest/proposer_slashing_minimal_test.go
@@ -1,9 +0,0 @@
-package spectest
-
-import (
-	"testing"
-)
-
-func TestProposerSlashingMinimal(t *testing.T) {
-	runProposerSlashingTest(t, "minimal")
-}
--- a/beacon-chain/core/blocks/spectest/proposer_slashing_test.go
+++ b/beacon-chain/core/blocks/spectest/proposer_slashing_test.go
@@ -1,30 +0,0 @@
-package spectest
-
-import (
-	"path"
-	"testing"
-
-	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
-	"github.com/prysmaticlabs/prysm/shared/params/spectest"
-	"github.com/prysmaticlabs/prysm/shared/testutil"
-	"github.com/prysmaticlabs/prysm/shared/testutil/require"
-)
-
-func runProposerSlashingTest(t *testing.T, config string) {
-	require.NoError(t, spectest.SetConfig(t, config))
-
-	testFolders, testsFolderPath := testutil.TestFolders(t, config, "operations/proposer_slashing/pyspec_tests")
-	for _, folder := range testFolders {
-		t.Run(folder.Name(), func(t *testing.T) {
-			folderPath := path.Join(testsFolderPath, folder.Name())
-			proposerSlashingFile, err := testutil.BazelFileBytes(folderPath, "proposer_slashing.ssz")
-			require.NoError(t, err)
-			proposerSlashing := &ethpb.ProposerSlashing{}
-			require.NoError(t, proposerSlashing.UnmarshalSSZ(proposerSlashingFile), "Failed to unmarshal")
-
-			body := &ethpb.BeaconBlockBody{ProposerSlashings: []*ethpb.ProposerSlashing{proposerSlashing}}
-			testutil.RunBlockOperationTest(t, folderPath, body, blocks.ProcessProposerSlashings)
-		})
-	}
-}
--- a/beacon-chain/core/blocks/spectest/voluntary_exit_mainnet_test.go
+++ b/beacon-chain/core/blocks/spectest/voluntary_exit_mainnet_test.go
@@ -1,9 +0,0 @@
-package spectest
-
-import (
-	"testing"
-)
-
-func TestVoluntaryExitMainnet(t *testing.T) {
-	runVoluntaryExitTest(t, "mainnet")
-}
--- a/beacon-chain/core/blocks/spectest/voluntary_exit_minimal_test.go
+++ b/beacon-chain/core/blocks/spectest/voluntary_exit_minimal_test.go
@@ -1,9 +0,0 @@
-package spectest
-
-import (
-	"testing"
-)
-
-func TestVoluntaryExitMinimal(t *testing.T) {
-	runVoluntaryExitTest(t, "minimal")
-}
--- a/beacon-chain/core/blocks/spectest/voluntary_exit_test.go
+++ b/beacon-chain/core/blocks/spectest/voluntary_exit_test.go
@@ -1,30 +0,0 @@
-package spectest
-
-import (
-	"path"
-	"testing"
-
-	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
-	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
-	"github.com/prysmaticlabs/prysm/shared/params/spectest"
-	"github.com/prysmaticlabs/prysm/shared/testutil"
-	"github.com/prysmaticlabs/prysm/shared/testutil/require"
-)
-
-func runVoluntaryExitTest(t *testing.T, config string) {
-	require.NoError(t, spectest.SetConfig(t, config))
-
-	testFolders, testsFolderPath := testutil.TestFolders(t, config, "operations/voluntary_exit/pyspec_tests")
-	for _, folder := range testFolders {
-		t.Run(folder.Name(), func(t *testing.T) {
-			folderPath := path.Join(testsFolderPath, folder.Name())
-			exitFile, err := testutil.BazelFileBytes(folderPath, "voluntary_exit.ssz")
-			require.NoError(t, err)
-			voluntaryExit := &ethpb.SignedVoluntaryExit{}
-			require.NoError(t, voluntaryExit.UnmarshalSSZ(exitFile), "Failed to unmarshal")
-
-			body := &ethpb.BeaconBlockBody{VoluntaryExits: []*ethpb.SignedVoluntaryExit{voluntaryExit}}
-			testutil.RunBlockOperationTest(t, folderPath, body, blocks.ProcessVoluntaryExits)
-		})
-	}
-}
--- a/beacon-chain/core/epoch/BUILD.bazel
+++ b/beacon-chain/core/epoch/BUILD.bazel
@@ -5,13 +5,18 @@ go_library(
    name = "go_default_library",
    srcs = ["epoch_processing.go"],
    importpath = "github.com/prysmaticlabs/prysm/beacon-chain/core/epoch",
-    visibility = ["//beacon-chain:__subpackages__"],
+    visibility = [
+        "//beacon-chain:__subpackages__",
+        "//spectest:__subpackages__",
+    ],
    deps = [
        "//beacon-chain/core/helpers:go_default_library",
        "//beacon-chain/core/validators:go_default_library",
-        "//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/attestationutil:go_default_library",
+        "//shared/featureconfig:go_default_library",
        "//shared/mathutil:go_default_library",
        "//shared/params:go_default_library",
        "@com_github_pkg_errors//:go_default_library",
@@ -30,16 +35,17 @@ go_test(
    embed = [":go_default_library"],
    deps = [
        "//beacon-chain/core/helpers:go_default_library",
-        "//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/params:go_default_library",
        "//shared/testutil: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",
        "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
+        "@org_golang_google_protobuf//proto:go_default_library",
    ],
 )
--- a/beacon-chain/core/epoch/epoch_processing.go
+++ b/beacon-chain/core/epoch/epoch_processing.go
@@ -13,9 +13,11 @@ import (
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/validators"
-	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/attestationutil"
+	"github.com/prysmaticlabs/prysm/shared/featureconfig"
 	"github.com/prysmaticlabs/prysm/shared/mathutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
 )
@@ -27,8 +29,13 @@ type sortableIndices struct {
 	validators []*ethpb.Validator
 }

-func (s sortableIndices) Len() int      { return len(s.indices) }
+// Len is the number of elements in the collection.
+func (s sortableIndices) Len() int { return len(s.indices) }
+
+// Swap swaps the elements with indexes i and j.
 func (s sortableIndices) Swap(i, j int) { s.indices[i], s.indices[j] = s.indices[j], s.indices[i] }
+
+// Less reports whether the element with index i must sort before the element with index j.
 func (s sortableIndices) Less(i, j int) bool {
 	if s.validators[s.indices[i]].ActivationEligibilityEpoch == s.validators[s.indices[j]].ActivationEligibilityEpoch {
 		return s.indices[i] < s.indices[j]
@@ -43,9 +50,13 @@ func (s sortableIndices) Less(i, j int) bool {
 // need to get attesting balance from attestations.
 //
 // Spec pseudocode definition:
-//  def get_attesting_balance(state: BeaconState, attestations: List[PendingAttestation]) -> Gwei:
+//  def get_attesting_balance(state: BeaconState, attestations: Sequence[PendingAttestation]) -> Gwei:
+//    """
+//    Return the combined effective balance of the set of unslashed validators participating in ``attestations``.
+//    Note: ``get_total_balance`` returns ``EFFECTIVE_BALANCE_INCREMENT`` Gwei minimum to avoid divisions by zero.
+//    """
 //    return get_total_balance(state, get_unslashed_attesting_indices(state, attestations))
-func AttestingBalance(state *stateTrie.BeaconState, atts []*pb.PendingAttestation) (uint64, error) {
+func AttestingBalance(state iface.ReadOnlyBeaconState, atts []*pb.PendingAttestation) (uint64, error) {
 	indices, err := UnslashedAttestingIndices(state, atts)
 	if err != nil {
 		return 0, errors.Wrap(err, "could not get attesting indices")
@@ -76,7 +87,7 @@ func AttestingBalance(state *stateTrie.BeaconState, atts []*pb.PendingAttestatio
 //    for index in activation_queue[:get_validator_churn_limit(state)]:
 //        validator = state.validators[index]
 //        validator.activation_epoch = compute_activation_exit_epoch(get_current_epoch(state))
-func ProcessRegistryUpdates(state *stateTrie.BeaconState) (*stateTrie.BeaconState, error) {
+func ProcessRegistryUpdates(state iface.BeaconState) (iface.BeaconState, error) {
 	currentEpoch := helpers.CurrentEpoch(state)
 	vals := state.Validators()
 	var err error
@@ -152,10 +163,10 @@ func ProcessRegistryUpdates(state *stateTrie.BeaconState) (*stateTrie.BeaconStat
 //    for index, validator in enumerate(state.validators):
 //        if validator.slashed and epoch + EPOCHS_PER_SLASHINGS_VECTOR // 2 == validator.withdrawable_epoch:
 //            increment = EFFECTIVE_BALANCE_INCREMENT  # Factored out from penalty numerator to avoid uint64 overflow
-//			  penalty_numerator = validator.effective_balance // increment * adjusted_total_slashing_balance
+//            penalty_numerator = validator.effective_balance // increment * adjusted_total_slashing_balance
 //            penalty = penalty_numerator // total_balance * increment
 //            decrease_balance(state, ValidatorIndex(index), penalty)
-func ProcessSlashings(state *stateTrie.BeaconState) (*stateTrie.BeaconState, error) {
+func ProcessSlashings(state iface.BeaconState) (iface.BeaconState, error) {
 	currentEpoch := helpers.CurrentEpoch(state)
 	totalBalance, err := helpers.TotalActiveBalance(state)
 	if err != nil {
@@ -191,47 +202,15 @@ func ProcessSlashings(state *stateTrie.BeaconState) (*stateTrie.BeaconState, err
 	return state, err
 }

-// ProcessFinalUpdates processes the final updates during epoch processing.
+// ProcessEth1DataReset processes updates to ETH1 data votes during epoch processing.
 //
 // Spec pseudocode definition:
-//  def process_final_updates(state: BeaconState) -> None:
-//    current_epoch = get_current_epoch(state)
-//    next_epoch = Epoch(current_epoch + 1)
+//  def process_eth1_data_reset(state: BeaconState) -> None:
+//    next_epoch = Epoch(get_current_epoch(state) + 1)
 //    # Reset eth1 data votes
 //    if next_epoch % EPOCHS_PER_ETH1_VOTING_PERIOD == 0:
 //        state.eth1_data_votes = []
-//    # Update effective balances with hysteresis
-//    for index, validator in enumerate(state.validators):
-//        balance = state.balances[index]
-//        HYSTERESIS_INCREMENT = EFFECTIVE_BALANCE_INCREMENT // HYSTERESIS_QUOTIENT
-//        DOWNWARD_THRESHOLD = HYSTERESIS_INCREMENT * HYSTERESIS_DOWNWARD_MULTIPLIER
-//        UPWARD_THRESHOLD = HYSTERESIS_INCREMENT * HYSTERESIS_UPWARD_MULTIPLIER
-//        if (
-//            balance + DOWNWARD_THRESHOLD < validator.effective_balance
-//            or validator.effective_balance + UPWARD_THRESHOLD < balance
-//        ):
-//        validator.effective_balance = min(balance - balance % EFFECTIVE_BALANCE_INCREMENT, MAX_EFFECTIVE_BALANCE)
-//    index_epoch = Epoch(next_epoch + ACTIVATION_EXIT_DELAY)
-//    index_root_position = index_epoch % EPOCHS_PER_HISTORICAL_VECTOR
-//    indices_list = List[ValidatorIndex, VALIDATOR_REGISTRY_LIMIT](get_active_validator_indices(state, index_epoch))
-//    state.active_index_roots[index_root_position] = hash_tree_root(indices_list)
-//    # Set committees root
-//    committee_root_position = next_epoch % EPOCHS_PER_HISTORICAL_VECTOR
-//    state.compact_committees_roots[committee_root_position] = get_compact_committees_root(state, next_epoch)
-//    # Reset slashings
-//    state.slashings[next_epoch % EPOCHS_PER_SLASHINGS_VECTOR] = Gwei(0)
-//    # Set randao mix
-//    state.randao_mixes[next_epoch % EPOCHS_PER_HISTORICAL_VECTOR] = get_randao_mix(state, current_epoch)
-//    # Set historical root accumulator
-//    if next_epoch % (SLOTS_PER_HISTORICAL_ROOT // SLOTS_PER_EPOCH) == 0:
-//        historical_batch = HistoricalBatch(block_roots=state.block_roots, state_roots=state.state_roots)
-//        state.historical_roots.append(hash_tree_root(historical_batch))
-//    # Update start shard
-//    state.start_shard = Shard((state.start_shard + get_shard_delta(state, current_epoch)) % SHARD_COUNT)
-//    # Rotate current/previous epoch attestations
-//    state.previous_epoch_attestations = state.current_epoch_attestations
-//    state.current_epoch_attestations = []
-func ProcessFinalUpdates(state *stateTrie.BeaconState) (*stateTrie.BeaconState, error) {
+func ProcessEth1DataReset(state iface.BeaconState) (iface.BeaconState, error) {
 	currentEpoch := helpers.CurrentEpoch(state)
 	nextEpoch := currentEpoch + 1

@@ -242,6 +221,25 @@ func ProcessFinalUpdates(state *stateTrie.BeaconState) (*stateTrie.BeaconState,
 		}
 	}

+	return state, nil
+}
+
+// ProcessEffectiveBalanceUpdates processes effective balance updates during epoch processing.
+//
+// Spec pseudocode definition:
+//  def process_effective_balance_updates(state: BeaconState) -> None:
+//    # Update effective balances with hysteresis
+//    for index, validator in enumerate(state.validators):
+//        balance = state.balances[index]
+//        HYSTERESIS_INCREMENT = uint64(EFFECTIVE_BALANCE_INCREMENT // HYSTERESIS_QUOTIENT)
+//        DOWNWARD_THRESHOLD = HYSTERESIS_INCREMENT * HYSTERESIS_DOWNWARD_MULTIPLIER
+//        UPWARD_THRESHOLD = HYSTERESIS_INCREMENT * HYSTERESIS_UPWARD_MULTIPLIER
+//        if (
+//            balance + DOWNWARD_THRESHOLD < validator.effective_balance
+//            or validator.effective_balance + UPWARD_THRESHOLD < balance
+//        ):
+//            validator.effective_balance = min(balance - balance % EFFECTIVE_BALANCE_INCREMENT, MAX_EFFECTIVE_BALANCE)
+func ProcessEffectiveBalanceUpdates(state iface.BeaconState) (iface.BeaconState, error) {
 	effBalanceInc := params.BeaconConfig().EffectiveBalanceIncrement
 	maxEffBalance := params.BeaconConfig().MaxEffectiveBalance
 	hysteresisInc := effBalanceInc / params.BeaconConfig().HysteresisQuotient
@@ -260,7 +258,7 @@ func ProcessFinalUpdates(state *stateTrie.BeaconState) (*stateTrie.BeaconState,
 		balance := bals[idx]

 		if balance+downwardThreshold < val.EffectiveBalance || val.EffectiveBalance+upwardThreshold < balance {
-			newVal := stateTrie.CopyValidator(val)
+			newVal := stateV0.CopyValidator(val)
 			newVal.EffectiveBalance = maxEffBalance
 			if newVal.EffectiveBalance > balance-balance%effBalanceInc {
 				newVal.EffectiveBalance = balance - balance%effBalanceInc
@@ -270,10 +268,50 @@ func ProcessFinalUpdates(state *stateTrie.BeaconState) (*stateTrie.BeaconState,
 		return false, val, nil
 	}

+	if featureconfig.Get().EnableOptimizedBalanceUpdate {
+		validatorFunc = func(idx int, val *ethpb.Validator) (bool, *ethpb.Validator, error) {
+			if val == nil {
+				return false, nil, fmt.Errorf("validator %d is nil in state", idx)
+			}
+			if idx >= len(bals) {
+				return false, nil, fmt.Errorf("validator index exceeds validator length in state %d >= %d", idx, len(state.Balances()))
+			}
+			balance := bals[idx]
+
+			if balance+downwardThreshold < val.EffectiveBalance || val.EffectiveBalance+upwardThreshold < balance {
+				effectiveBal := maxEffBalance
+				if effectiveBal > balance-balance%effBalanceInc {
+					effectiveBal = balance - balance%effBalanceInc
+				}
+				if effectiveBal != val.EffectiveBalance {
+					newVal := stateV0.CopyValidator(val)
+					newVal.EffectiveBalance = effectiveBal
+					return true, newVal, nil
+				}
+				return false, val, nil
+			}
+			return false, val, nil
+		}
+	}
+
 	if err := state.ApplyToEveryValidator(validatorFunc); err != nil {
 		return nil, err
 	}

+	return state, nil
+}
+
+// ProcessSlashingsReset processes the total slashing balances updates during epoch processing.
+//
+// Spec pseudocode definition:
+//  def process_slashings_reset(state: BeaconState) -> None:
+//    next_epoch = Epoch(get_current_epoch(state) + 1)
+//    # Reset slashings
+//    state.slashings[next_epoch % EPOCHS_PER_SLASHINGS_VECTOR] = Gwei(0)
+func ProcessSlashingsReset(state iface.BeaconState) (iface.BeaconState, error) {
+	currentEpoch := helpers.CurrentEpoch(state)
+	nextEpoch := currentEpoch + 1
+
 	// Set total slashed balances.
 	slashedExitLength := params.BeaconConfig().EpochsPerSlashingsVector
 	slashedEpoch := nextEpoch % slashedExitLength
@@ -289,6 +327,21 @@ func ProcessFinalUpdates(state *stateTrie.BeaconState) (*stateTrie.BeaconState,
 		return nil, err
 	}

+	return state, nil
+}
+
+// ProcessRandaoMixesReset processes the final updates to RANDAO mix during epoch processing.
+//
+// Spec pseudocode definition:
+//  def process_randao_mixes_reset(state: BeaconState) -> None:
+//    current_epoch = get_current_epoch(state)
+//    next_epoch = Epoch(current_epoch + 1)
+//    # Set randao mix
+//    state.randao_mixes[next_epoch % EPOCHS_PER_HISTORICAL_VECTOR] = get_randao_mix(state, current_epoch)
+func ProcessRandaoMixesReset(state iface.BeaconState) (iface.BeaconState, error) {
+	currentEpoch := helpers.CurrentEpoch(state)
+	nextEpoch := currentEpoch + 1
+
 	// Set RANDAO mix.
 	randaoMixLength := params.BeaconConfig().EpochsPerHistoricalVector
 	if uint64(state.RandaoMixesLength()) != uint64(randaoMixLength) {
@@ -306,6 +359,22 @@ func ProcessFinalUpdates(state *stateTrie.BeaconState) (*stateTrie.BeaconState,
 		return nil, err
 	}

+	return state, nil
+}
+
+// ProcessHistoricalRootsUpdate processes the updates to historical root accumulator during epoch processing.
+//
+// Spec pseudocode definition:
+//  def process_historical_roots_update(state: BeaconState) -> None:
+//    # Set historical root accumulator
+//    next_epoch = Epoch(get_current_epoch(state) + 1)
+//    if next_epoch % (SLOTS_PER_HISTORICAL_ROOT // SLOTS_PER_EPOCH) == 0:
+//        historical_batch = HistoricalBatch(block_roots=state.block_roots, state_roots=state.state_roots)
+//        state.historical_roots.append(hash_tree_root(historical_batch))
+func ProcessHistoricalRootsUpdate(state iface.BeaconState) (iface.BeaconState, error) {
+	currentEpoch := helpers.CurrentEpoch(state)
+	nextEpoch := currentEpoch + 1
+
 	// Set historical root accumulator.
 	epochsPerHistoricalRoot := params.BeaconConfig().SlotsPerHistoricalRoot.DivSlot(params.BeaconConfig().SlotsPerEpoch)
 	if nextEpoch.Mod(uint64(epochsPerHistoricalRoot)) == 0 {
@@ -322,13 +391,63 @@ func ProcessFinalUpdates(state *stateTrie.BeaconState) (*stateTrie.BeaconState,
 		}
 	}

+	return state, nil
+}
+
+// ProcessParticipationRecordUpdates rotates current/previous epoch attestations during epoch processing.
+//
+// Spec pseudocode definition:
+//  def process_participation_record_updates(state: BeaconState) -> None:
+//    # Rotate current/previous epoch attestations
+//    state.previous_epoch_attestations = state.current_epoch_attestations
+//    state.current_epoch_attestations = []
+func ProcessParticipationRecordUpdates(state iface.BeaconState) (iface.BeaconState, error) {
+	if err := state.RotateAttestations(); err != nil {
+		return nil, err
+	}
+	return state, nil
+}
+
+// ProcessFinalUpdates processes the final updates during epoch processing.
+func ProcessFinalUpdates(state iface.BeaconState) (iface.BeaconState, error) {
+	var err error
+
+	// Reset ETH1 data votes.
+	state, err = ProcessEth1DataReset(state)
+	if err != nil {
+		return nil, err
+	}
+
+	// Update effective balances with hysteresis.
+	state, err = ProcessEffectiveBalanceUpdates(state)
+	if err != nil {
+		return nil, err
+	}
+
+	// Set total slashed balances.
+	state, err = ProcessSlashingsReset(state)
+	if err != nil {
+		return nil, err
+	}
+
+	// Set RANDAO mix.
+	state, err = ProcessRandaoMixesReset(state)
+	if err != nil {
+		return nil, err
+	}
+
+	// Set historical root accumulator.
+	state, err = ProcessHistoricalRootsUpdate(state)
+	if err != nil {
+		return nil, err
+	}
+
 	// Rotate current and previous epoch attestations.
-	if err := state.SetPreviousEpochAttestations(state.CurrentEpochAttestations()); err != nil {
-		return nil, err
-	}
-	if err := state.SetCurrentEpochAttestations([]*pb.PendingAttestation{}); err != nil {
+	state, err = ProcessParticipationRecordUpdates(state)
+	if err != nil {
 		return nil, err
 	}
+
 	return state, nil
 }

@@ -342,7 +461,7 @@ func ProcessFinalUpdates(state *stateTrie.BeaconState) (*stateTrie.BeaconState,
 //    for a in attestations:
 //        output = output.union(get_attesting_indices(state, a.data, a.aggregation_bits))
 //    return set(filter(lambda index: not state.validators[index].slashed, output))
-func UnslashedAttestingIndices(state *stateTrie.BeaconState, atts []*pb.PendingAttestation) ([]types.ValidatorIndex, error) {
+func UnslashedAttestingIndices(state iface.ReadOnlyBeaconState, atts []*pb.PendingAttestation) ([]types.ValidatorIndex, error) {
 	var setIndices []types.ValidatorIndex
 	seen := make(map[uint64]bool)

@@ -387,10 +506,10 @@ func UnslashedAttestingIndices(state *stateTrie.BeaconState, atts []*pb.PendingA
 //
 // Spec pseudocode definition:
 //  def get_base_reward(state: BeaconState, index: ValidatorIndex) -> Gwei:
-//      total_balance = get_total_active_balance(state)
-//	    effective_balance = state.validator_registry[index].effective_balance
-//	    return effective_balance * BASE_REWARD_FACTOR // integer_squareroot(total_balance) // BASE_REWARDS_PER_EPOCH
-func BaseReward(state *stateTrie.BeaconState, index types.ValidatorIndex) (uint64, error) {
+//    total_balance = get_total_active_balance(state)
+//    effective_balance = state.validators[index].effective_balance
+//    return Gwei(effective_balance * BASE_REWARD_FACTOR // integer_squareroot(total_balance) // BASE_REWARDS_PER_EPOCH)
+func BaseReward(state iface.ReadOnlyBeaconState, index types.ValidatorIndex) (uint64, error) {
 	totalBalance, err := helpers.TotalActiveBalance(state)
 	if err != nil {
 		return 0, errors.Wrap(err, "could not calculate active balance")
--- a/beacon-chain/core/epoch/epoch_processing_fuzz_test.go
+++ b/beacon-chain/core/epoch/epoch_processing_fuzz_test.go
@@ -4,7 +4,7 @@ import (
 	"testing"

 	fuzz "github.com/google/gofuzz"
-	beaconstate "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state/stateV0"
 	ethereum_beacon_p2p_v1 "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
 	"github.com/prysmaticlabs/prysm/shared/testutil/require"
 )
@@ -15,7 +15,7 @@ func TestFuzzFinalUpdates_10000(t *testing.T) {

 	for i := 0; i < 10000; i++ {
 		fuzzer.Fuzz(base)
-		s, err := beaconstate.InitializeFromProtoUnsafe(base)
+		s, err := stateV0.InitializeFromProtoUnsafe(base)
 		require.NoError(t, err)
 		_, err = ProcessFinalUpdates(s)
 		_ = err
--- a/beacon-chain/core/epoch/epoch_processing_test.go
+++ b/beacon-chain/core/epoch/epoch_processing_test.go
@@ -4,18 +4,19 @@ import (
 	"fmt"
 	"testing"

-	"github.com/gogo/protobuf/proto"
 	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/epoch"
 	"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/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"
+	"google.golang.org/protobuf/proto"
 )

 func TestUnslashedAttestingIndices_CanSortAndFilter(t *testing.T) {
@@ -42,7 +43,7 @@ func TestUnslashedAttestingIndices_CanSortAndFilter(t *testing.T) {
 		Validators:  validators,
 		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
 	}
-	beaconState, err := state.InitializeFromProto(base)
+	beaconState, err := stateV0.InitializeFromProto(base)
 	require.NoError(t, err)

 	indices, err := epoch.UnslashedAttestingIndices(beaconState, atts)
@@ -88,7 +89,7 @@ func TestUnslashedAttestingIndices_DuplicatedAttestations(t *testing.T) {
 		Validators:  validators,
 		RandaoMixes: make([][]byte, params.BeaconConfig().EpochsPerHistoricalVector),
 	}
-	beaconState, err := state.InitializeFromProto(base)
+	beaconState, err := stateV0.InitializeFromProto(base)
 	require.NoError(t, err)

 	indices, err := epoch.UnslashedAttestingIndices(beaconState, atts)
@@ -134,7 +135,7 @@ func TestAttestingBalance_CorrectBalance(t *testing.T) {
 		Validators: validators,
 		Balances:   balances,
 	}
-	beaconState, err := state.InitializeFromProto(base)
+	beaconState, err := stateV0.InitializeFromProto(base)
 	require.NoError(t, err)

 	balance, err := epoch.AttestingBalance(beaconState, atts)
@@ -160,7 +161,7 @@ func TestBaseReward_AccurateRewards(t *testing.T) {
 				{ExitEpoch: params.BeaconConfig().FarFutureEpoch, EffectiveBalance: tt.b}},
 			Balances: []uint64{tt.a},
 		}
-		beaconState, err := state.InitializeFromProto(base)
+		beaconState, err := stateV0.InitializeFromProto(base)
 		require.NoError(t, err)
 		c, err := epoch.BaseReward(beaconState, 0)
 		require.NoError(t, err)
@@ -175,7 +176,7 @@ func TestProcessSlashings_NotSlashed(t *testing.T) {
 		Balances:   []uint64{params.BeaconConfig().MaxEffectiveBalance},
 		Slashings:  []uint64{0, 1e9},
 	}
-	s, err := state.InitializeFromProto(base)
+	s, err := stateV0.InitializeFromProto(base)
 	require.NoError(t, err)
 	newState, err := epoch.ProcessSlashings(s)
 	require.NoError(t, err)
@@ -253,7 +254,7 @@ func TestProcessSlashings_SlashedLess(t *testing.T) {
 	for i, tt := range tests {
 		t.Run(fmt.Sprint(i), func(t *testing.T) {
 			original := proto.Clone(tt.state)
-			s, err := state.InitializeFromProto(tt.state)
+			s, err := stateV0.InitializeFromProto(tt.state)
 			require.NoError(t, err)
 			newState, err := epoch.ProcessSlashings(s)
 			require.NoError(t, err)
@@ -295,7 +296,9 @@ func TestProcessFinalUpdates_CanProcess(t *testing.T) {

 	// Verify historical root accumulator was appended.
 	assert.Equal(t, 1, len(newS.HistoricalRoots()), "Unexpected slashed balance")
-	assert.NotNil(t, newS.CurrentEpochAttestations(), "Nil value stored in current epoch attestations instead of empty slice")
+	currAtt, err := newS.CurrentEpochAttestations()
+	require.NoError(t, err)
+	assert.NotNil(t, currAtt, "Nil value stored in current epoch attestations instead of empty slice")
 }

 func TestProcessRegistryUpdates_NoRotation(t *testing.T) {
@@ -311,7 +314,7 @@ func TestProcessRegistryUpdates_NoRotation(t *testing.T) {
 		},
 		FinalizedCheckpoint: &ethpb.Checkpoint{Root: make([]byte, 32)},
 	}
-	beaconState, err := state.InitializeFromProto(base)
+	beaconState, err := stateV0.InitializeFromProto(base)
 	require.NoError(t, err)
 	newState, err := epoch.ProcessRegistryUpdates(beaconState)
 	require.NoError(t, err)
@@ -334,7 +337,7 @@ func TestProcessRegistryUpdates_EligibleToActivate(t *testing.T) {
 			ActivationEpoch:            params.BeaconConfig().FarFutureEpoch,
 		})
 	}
-	beaconState, err := state.InitializeFromProto(base)
+	beaconState, err := stateV0.InitializeFromProto(base)
 	require.NoError(t, err)
 	currentEpoch := helpers.CurrentEpoch(beaconState)
 	newState, err := epoch.ProcessRegistryUpdates(beaconState)
@@ -363,7 +366,7 @@ func TestProcessRegistryUpdates_ActivationCompletes(t *testing.T) {
 		},
 		FinalizedCheckpoint: &ethpb.Checkpoint{Root: make([]byte, 32)},
 	}
-	beaconState, err := state.InitializeFromProto(base)
+	beaconState, err := stateV0.InitializeFromProto(base)
 	require.NoError(t, err)
 	newState, err := epoch.ProcessRegistryUpdates(beaconState)
 	require.NoError(t, err)
@@ -387,7 +390,7 @@ func TestProcessRegistryUpdates_ValidatorsEjected(t *testing.T) {
 		},
 		FinalizedCheckpoint: &ethpb.Checkpoint{Root: make([]byte, 32)},
 	}
-	beaconState, err := state.InitializeFromProto(base)
+	beaconState, err := stateV0.InitializeFromProto(base)
 	require.NoError(t, err)
 	newState, err := epoch.ProcessRegistryUpdates(beaconState)
 	require.NoError(t, err)
@@ -412,7 +415,7 @@ func TestProcessRegistryUpdates_CanExits(t *testing.T) {
 		},
 		FinalizedCheckpoint: &ethpb.Checkpoint{Root: make([]byte, 32)},
 	}
-	beaconState, err := state.InitializeFromProto(base)
+	beaconState, err := stateV0.InitializeFromProto(base)
 	require.NoError(t, err)
 	newState, err := epoch.ProcessRegistryUpdates(beaconState)
 	require.NoError(t, err)
@@ -421,7 +424,7 @@ func TestProcessRegistryUpdates_CanExits(t *testing.T) {
 	}
 }

-func buildState(t testing.TB, slot types.Slot, validatorCount uint64) *state.BeaconState {
+func buildState(t testing.TB, slot types.Slot, validatorCount uint64) iface.BeaconState {
 	validators := make([]*ethpb.Validator, validatorCount)
 	for i := 0; i < len(validators); i++ {
 		validators[i] = &ethpb.Validator{
--- a/beacon-chain/core/epoch/precompute/BUILD.bazel
+++ b/beacon-chain/core/epoch/precompute/BUILD.bazel
@@ -12,10 +12,12 @@ go_library(
        "type.go",
    ],
    importpath = "github.com/prysmaticlabs/prysm/beacon-chain/core/epoch/precompute",
-    visibility = ["//beacon-chain:__subpackages__"],
+    visibility = [
+        "//beacon-chain:__subpackages__",
+        "//spectest:__subpackages__",
+    ],
    deps = [
        "//beacon-chain/core/helpers:go_default_library",
-        "//beacon-chain/state:go_default_library",
        "//beacon-chain/state/interface:go_default_library",
        "//proto/beacon/p2p/v1:go_default_library",
        "//shared/attestationutil:go_default_library",
@@ -42,7 +44,7 @@ go_test(
    deps = [
        "//beacon-chain/core/epoch:go_default_library",
        "//beacon-chain/core/helpers:go_default_library",
-        "//beacon-chain/state:go_default_library",
+        "//beacon-chain/state/stateV0:go_default_library",
        "//proto/beacon/p2p/v1:go_default_library",
        "//shared/attestationutil:go_default_library",
        "//shared/mathutil:go_default_library",
@@ -50,9 +52,9 @@ go_test(
        "//shared/testutil: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_prysmaticlabs_eth2_types//:go_default_library",
        "@com_github_prysmaticlabs_ethereumapis//eth/v1alpha1:go_default_library",
        "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
+        "@org_golang_google_protobuf//proto:go_default_library",
    ],
 )
--- a/beacon-chain/core/epoch/precompute/attestation.go
+++ b/beacon-chain/core/epoch/precompute/attestation.go
@@ -7,7 +7,7 @@ import (
 	"github.com/pkg/errors"
 	types "github.com/prysmaticlabs/eth2-types"
 	"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"
 	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
 	"github.com/prysmaticlabs/prysm/shared/attestationutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
@@ -19,7 +19,7 @@ import (
 // it also tracks and updates epoch attesting balances.
 func ProcessAttestations(
 	ctx context.Context,
-	state *stateTrie.BeaconState,
+	state iface.ReadOnlyBeaconState,
 	vp []*Validator,
 	pBal *Balance,
 ) ([]*Validator, *Balance, error) {
@@ -29,7 +29,15 @@ func ProcessAttestations(
 	v := &Validator{}
 	var err error

-	for _, a := range append(state.PreviousEpochAttestations(), state.CurrentEpochAttestations()...) {
+	prevAtt, err := state.PreviousEpochAttestations()
+	if err != nil {
+		return nil, nil, err
+	}
+	curAtt, err := state.CurrentEpochAttestations()
+	if err != nil {
+		return nil, nil, err
+	}
+	for _, a := range append(prevAtt, curAtt...) {
 		if a.InclusionDelay == 0 {
 			return nil, nil, errors.New("attestation with inclusion delay of 0")
 		}
@@ -61,7 +69,7 @@ func ProcessAttestations(
 }

 // AttestedCurrentEpoch returns true if attestation `a` attested once in current epoch and/or epoch boundary block.
-func AttestedCurrentEpoch(s *stateTrie.BeaconState, a *pb.PendingAttestation) (bool, bool, error) {
+func AttestedCurrentEpoch(s iface.ReadOnlyBeaconState, a *pb.PendingAttestation) (bool, bool, error) {
 	currentEpoch := helpers.CurrentEpoch(s)
 	var votedCurrentEpoch, votedTarget bool
 	// Did validator vote current epoch.
@@ -79,7 +87,7 @@ func AttestedCurrentEpoch(s *stateTrie.BeaconState, a *pb.PendingAttestation) (b
 }

 // AttestedPrevEpoch returns true if attestation `a` attested once in previous epoch and epoch boundary block and/or the same head.
-func AttestedPrevEpoch(s *stateTrie.BeaconState, a *pb.PendingAttestation) (bool, bool, bool, error) {
+func AttestedPrevEpoch(s iface.ReadOnlyBeaconState, a *pb.PendingAttestation) (bool, bool, bool, error) {
 	prevEpoch := helpers.PrevEpoch(s)
 	var votedPrevEpoch, votedTarget, votedHead bool
 	// Did validator vote previous epoch.
@@ -107,7 +115,7 @@ func AttestedPrevEpoch(s *stateTrie.BeaconState, a *pb.PendingAttestation) (bool
 }

 // SameTarget returns true if attestation `a` attested to the same target block in state.
-func SameTarget(state *stateTrie.BeaconState, a *pb.PendingAttestation, e types.Epoch) (bool, error) {
+func SameTarget(state iface.ReadOnlyBeaconState, a *pb.PendingAttestation, e types.Epoch) (bool, error) {
 	r, err := helpers.BlockRoot(state, e)
 	if err != nil {
 		return false, err
@@ -119,7 +127,7 @@ func SameTarget(state *stateTrie.BeaconState, a *pb.PendingAttestation, e types.
 }

 // SameHead returns true if attestation `a` attested to the same block by attestation slot in state.
-func SameHead(state *stateTrie.BeaconState, a *pb.PendingAttestation) (bool, error) {
+func SameHead(state iface.ReadOnlyBeaconState, a *pb.PendingAttestation) (bool, error) {
 	r, err := helpers.BlockRootAtSlot(state, a.Data.Slot)
 	if err != nil {
 		return false, err
--- a/beacon-chain/core/epoch/precompute/attestation_test.go
+++ b/beacon-chain/core/epoch/precompute/attestation_test.go
@@ -170,9 +170,9 @@ func TestProcessAttestations(t *testing.T) {
 	require.NoError(t, beaconState.SetBlockRoots(br))
 	att2.Data.Target.Root = newRt[:]
 	att2.Data.BeaconBlockRoot = newRt[:]
-	err := beaconState.SetPreviousEpochAttestations([]*pb.PendingAttestation{{Data: att1.Data, AggregationBits: bf, InclusionDelay: 1}})
+	err := beaconState.AppendPreviousEpochAttestations(&pb.PendingAttestation{Data: att1.Data, AggregationBits: bf, InclusionDelay: 1})
 	require.NoError(t, err)
-	err = beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{{Data: att2.Data, AggregationBits: bf, InclusionDelay: 1}})
+	err = beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{Data: att2.Data, AggregationBits: bf, InclusionDelay: 1})
 	require.NoError(t, err)

 	pVals := make([]*precompute.Validator, validators)
--- a/beacon-chain/core/epoch/precompute/justification_finalization.go
+++ b/beacon-chain/core/epoch/precompute/justification_finalization.go
@@ -4,16 +4,45 @@ import (
 	"github.com/pkg/errors"
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"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"
 )

 // ProcessJustificationAndFinalizationPreCompute processes justification and finalization during
 // epoch processing. This is where a beacon node can justify and finalize a new epoch.
 // Note: this is an optimized version by passing in precomputed total and attesting balances.
-// def process_justification_and_finalization(state: BeaconState) -> None:
+//
+// Spec pseudocode definition:
+//  def process_justification_and_finalization(state: BeaconState) -> None:
+//    # Initial FFG checkpoint values have a `0x00` stub for `root`.
+//    # Skip FFG updates in the first two epochs to avoid corner cases that might result in modifying this stub.
 //    if get_current_epoch(state) <= GENESIS_EPOCH + 1:
 //        return
+//    previous_attestations = get_matching_target_attestations(state, get_previous_epoch(state))
+//    current_attestations = get_matching_target_attestations(state, get_current_epoch(state))
+//    total_active_balance = get_total_active_balance(state)
+//    previous_target_balance = get_attesting_balance(state, previous_attestations)
+//    current_target_balance = get_attesting_balance(state, current_attestations)
+//    weigh_justification_and_finalization(state, total_active_balance, previous_target_balance, current_target_balance)
+func ProcessJustificationAndFinalizationPreCompute(state iface.BeaconState, pBal *Balance) (iface.BeaconState, error) {
+	canProcessSlot, err := helpers.StartSlot(2 /*epoch*/)
+	if err != nil {
+		return nil, err
+	}
+	if state.Slot() <= canProcessSlot {
+		return state, nil
+	}
+
+	return weighJustificationAndFinalization(state, pBal.ActiveCurrentEpoch, pBal.PrevEpochTargetAttested, pBal.CurrentEpochTargetAttested)
+}
+
+// weighJustificationAndFinalization processes justification and finalization during
+// epoch processing. This is where a beacon node can justify and finalize a new epoch.
 //
+// Spec pseudocode definition:
+// def weigh_justification_and_finalization(state: BeaconState,
+//                                         total_active_balance: Gwei,
+//                                         previous_epoch_target_balance: Gwei,
+//                                         current_epoch_target_balance: Gwei) -> None:
 //    previous_epoch = get_previous_epoch(state)
 //    current_epoch = get_current_epoch(state)
 //    old_previous_justified_checkpoint = state.previous_justified_checkpoint
@@ -21,15 +50,13 @@ import (
 //
 //    # Process justifications
 //    state.previous_justified_checkpoint = state.current_justified_checkpoint
-//    state.justification_bits[1:] = state.justification_bits[:-1]
+//    state.justification_bits[1:] = state.justification_bits[:JUSTIFICATION_BITS_LENGTH - 1]
 //    state.justification_bits[0] = 0b0
-//    matching_target_attestations = get_matching_target_attestations(state, previous_epoch)  # Previous epoch
-//    if get_attesting_balance(state, matching_target_attestations) * 3 >= get_total_active_balance(state) * 2:
+//    if previous_epoch_target_balance * 3 >= total_active_balance * 2:
 //        state.current_justified_checkpoint = Checkpoint(epoch=previous_epoch,
 //                                                        root=get_block_root(state, previous_epoch))
 //        state.justification_bits[1] = 0b1
-//    matching_target_attestations = get_matching_target_attestations(state, current_epoch)  # Current epoch
-//    if get_attesting_balance(state, matching_target_attestations) * 3 >= get_total_active_balance(state) * 2:
+//    if current_epoch_target_balance * 3 >= total_active_balance * 2:
 //        state.current_justified_checkpoint = Checkpoint(epoch=current_epoch,
 //                                                        root=get_block_root(state, current_epoch))
 //        state.justification_bits[0] = 0b1
@@ -48,15 +75,8 @@ import (
 //    # The 1st/2nd most recent epochs are justified, the 1st using the 2nd as source
 //    if all(bits[0:2]) and old_current_justified_checkpoint.epoch + 1 == current_epoch:
 //        state.finalized_checkpoint = old_current_justified_checkpoint
-func ProcessJustificationAndFinalizationPreCompute(state *stateTrie.BeaconState, pBal *Balance) (*stateTrie.BeaconState, error) {
-	canProcessSlot, err := helpers.StartSlot(2 /*epoch*/)
-	if err != nil {
-		return nil, err
-	}
-	if state.Slot() <= canProcessSlot {
-		return state, nil
-	}
-
+func weighJustificationAndFinalization(state iface.BeaconState,
+	totalActiveBalance, prevEpochTargetBalance, currEpochTargetBalance uint64) (iface.BeaconState, error) {
 	prevEpoch := helpers.PrevEpoch(state)
 	currentEpoch := helpers.CurrentEpoch(state)
 	oldPrevJustifiedCheckpoint := state.PreviousJustifiedCheckpoint()
@@ -76,7 +96,7 @@ func ProcessJustificationAndFinalizationPreCompute(state *stateTrie.BeaconState,
 	// We will use that paradigm here for consistency with the godoc spec definition.

 	// If 2/3 or more of total balance attested in the previous epoch.
-	if 3*pBal.PrevEpochTargetAttested >= 2*pBal.ActiveCurrentEpoch {
+	if 3*prevEpochTargetBalance >= 2*totalActiveBalance {
 		blockRoot, err := helpers.BlockRoot(state, prevEpoch)
 		if err != nil {
 			return nil, errors.Wrapf(err, "could not get block root for previous epoch %d", prevEpoch)
@@ -92,7 +112,7 @@ func ProcessJustificationAndFinalizationPreCompute(state *stateTrie.BeaconState,
 	}

 	// If 2/3 or more of the total balance attested in the current epoch.
-	if 3*pBal.CurrentEpochTargetAttested >= 2*pBal.ActiveCurrentEpoch {
+	if 3*currEpochTargetBalance >= 2*totalActiveBalance {
 		blockRoot, err := helpers.BlockRoot(state, currentEpoch)
 		if err != nil {
 			return nil, errors.Wrapf(err, "could not get block root for current epoch %d", prevEpoch)
--- a/beacon-chain/core/epoch/precompute/justification_finalization_test.go
+++ b/beacon-chain/core/epoch/precompute/justification_finalization_test.go
@@ -7,7 +7,7 @@ import (
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/go-bitfield"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/epoch/precompute"
-	beaconstate "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	"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/assert"
@@ -37,7 +37,7 @@ func TestProcessJustificationAndFinalizationPreCompute_ConsecutiveEpochs(t *test
 		Balances:            []uint64{a, a, a, a}, // validator total balance should be 128000000000
 		BlockRoots:          blockRoots,
 	}
-	state, err := beaconstate.InitializeFromProto(base)
+	state, err := stateV0.InitializeFromProto(base)
 	require.NoError(t, err)
 	attestedBalance := 4 * uint64(e) * 3 / 2
 	b := &precompute.Balance{PrevEpochTargetAttested: attestedBalance}
@@ -74,7 +74,7 @@ func TestProcessJustificationAndFinalizationPreCompute_JustifyCurrentEpoch(t *te
 		Balances:            []uint64{a, a, a, a}, // validator total balance should be 128000000000
 		BlockRoots:          blockRoots,
 	}
-	state, err := beaconstate.InitializeFromProto(base)
+	state, err := stateV0.InitializeFromProto(base)
 	require.NoError(t, err)
 	attestedBalance := 4 * uint64(e) * 3 / 2
 	b := &precompute.Balance{PrevEpochTargetAttested: attestedBalance}
@@ -110,7 +110,7 @@ func TestProcessJustificationAndFinalizationPreCompute_JustifyPrevEpoch(t *testi
 		Balances:          []uint64{a, a, a, a}, // validator total balance should be 128000000000
 		BlockRoots:        blockRoots, FinalizedCheckpoint: &ethpb.Checkpoint{Root: make([]byte, 32)},
 	}
-	state, err := beaconstate.InitializeFromProto(base)
+	state, err := stateV0.InitializeFromProto(base)
 	require.NoError(t, err)
 	attestedBalance := 4 * uint64(e) * 3 / 2
 	b := &precompute.Balance{PrevEpochTargetAttested: attestedBalance}
--- a/beacon-chain/core/epoch/precompute/new.go
+++ b/beacon-chain/core/epoch/precompute/new.go
@@ -8,7 +8,6 @@ import (

 	"github.com/pkg/errors"
 	"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/params"
 	"go.opencensus.io/trace"
@@ -17,9 +16,10 @@ import (
 // New gets called at the beginning of process epoch cycle to return
 // pre computed instances of validators attesting records and total
 // balances attested in an epoch.
-func New(ctx context.Context, state *stateTrie.BeaconState) ([]*Validator, *Balance, error) {
+func New(ctx context.Context, state iface.BeaconState) ([]*Validator, *Balance, error) {
 	ctx, span := trace.StartSpan(ctx, "precomputeEpoch.New")
 	defer span.End()
+
 	pValidators := make([]*Validator, state.NumValidators())
 	pBal := &Balance{}

--- a/beacon-chain/core/epoch/precompute/new_test.go
+++ b/beacon-chain/core/epoch/precompute/new_test.go
@@ -6,7 +6,7 @@ import (

 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/epoch/precompute"
-	beaconstate "github.com/prysmaticlabs/prysm/beacon-chain/state"
+	"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/assert"
@@ -15,7 +15,7 @@ import (

 func TestNew(t *testing.T) {
 	ffe := params.BeaconConfig().FarFutureEpoch
-	s, err := beaconstate.InitializeFromProto(&pb.BeaconState{
+	s, err := stateV0.InitializeFromProto(&pb.BeaconState{
 		Slot: params.BeaconConfig().SlotsPerEpoch,
 		// Validator 0 is slashed
 		// Validator 1 is withdrawable
--- a/Show More
+++ b/Show More