Failing cases from the fuzzers in consensus-types/hdiff

Adds serialization code for state diffs.
Adds code to create and apply state diffs
Adds fuzz tests and benchmarks for serialization/deserialization

Co-authored-by: Claude <noreply@anthropic.com>

.bazelrc

@@ -34,6 +34,7 @@ build:minimal --@io_bazel_rules_go//go/config:tags=minimal
 build:release --compilation_mode=opt
 build:release --stamp
 build:release --define pgo_enabled=1
+build:release --strip=always
 
 # Build binary with cgo symbolizer for debugging / profiling.
 build:cgo_symbolizer --copt=-g

.github/actions/gomodtidy/Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.24-alpine
+FROM golang:1.25.1-alpine
 
 COPY entrypoint.sh /entrypoint.sh
 

.github/workflows/fuzz.yml

@@ -16,7 +16,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-go@v4
         with:
-          go-version: '1.23.5'
+          go-version: '1.25.1'
       - id: list
         uses: shogo82148/actions-go-fuzz/list@v0
         with:
@@ -36,7 +36,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-go@v4
         with:
-          go-version: '1.23.5'
+          go-version: '1.25.1'
       - uses: shogo82148/actions-go-fuzz/run@v0
         with:
           packages: ${{ matrix.package }}

.github/workflows/go.yml

@@ -31,7 +31,7 @@ jobs:
       - name: Set up Go 1.24
         uses: actions/setup-go@v4
         with:
-          go-version: '1.24.0'
+          go-version: '1.25.1'
       - name: Run Gosec Security Scanner
         run: | # https://github.com/securego/gosec/issues/469
           export PATH=$PATH:$(go env GOPATH)/bin
@@ -44,27 +44,27 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
-
-      - name: Set up Go 1.24
-        uses: actions/setup-go@v4
         with:
-          go-version: '1.24.0'
-          id: go
+          fetch-depth: 0
+
+      - name: Set up Go 1.25.1
+        uses: actions/setup-go@v5
+        with:
+          go-version: '1.25.1'
 
       - name: Golangci-lint
-        uses: golangci/golangci-lint-action@v5
+        uses: golangci/golangci-lint-action@v8
         with:
-          version: v1.64.5
-          args: --config=.golangci.yml --out-${NO_FUTURE}format colored-line-number
+          version: v2.4
 
   build:
     name: Build
     runs-on: ubuntu-latest
     steps:
-      - name: Set up Go 1.x
+      - name: Set up Go 1.25.1
         uses: actions/setup-go@v4
         with:
-          go-version: '1.24.0'
+          go-version: '1.25.1'
         id: go
 
       - name: Check out code into the Go module directory

.golangci.yml

@@ -1,90 +1,41 @@
+version: "2"
 run:
-  timeout: 10m
-  go: '1.23.5'
-
-issues:
-  exclude-files:
-    - validator/web/site_data.go
-    - .*_test.go
-  exclude-dirs:
-    - proto
-    - tools/analyzers
-
+  go: 1.23.5
 linters:
-  enable-all: true
-  disable:
-    # Deprecated linters:
+  enable:
+    - errcheck
+    - ineffassign
     - govet
-
-    # Disabled for now:
-    - asasalint
-    - bodyclose
-    - containedctx
-    - contextcheck
-    - cyclop
-    - depguard
-    - dogsled
-    - dupl
-    - durationcheck
-    - errname
-    - err113
-    - exhaustive
-    - exhaustruct
-    - forbidigo
-    - forcetypeassert
-    - funlen
-    - gci
-    - gochecknoglobals
-    - gochecknoinits
-    - goconst
-    - gocritic
-    - gocyclo
-    - godot
-    - godox
-    - gofumpt
-    - gomoddirectives
-    - gosec
-    - inamedparam
-    - interfacebloat
-    - intrange
-    - ireturn
-    - lll
-    - maintidx
-    - makezero
-    - mnd
-    - musttag
-    - nakedret
-    - nestif
-    - nilnil
-    - nlreturn
-    - noctx
-    - nolintlint
-    - nonamedreturns
-    - nosprintfhostport
-    - perfsprint
-    - prealloc
-    - predeclared
-    - promlinter
-    - protogetter
-    - recvcheck
-    - revive
-    - spancheck
+  disable:
     - staticcheck
-    - stylecheck
-    - tagalign
-    - tagliatelle
-    - thelper
-    - unparam
-    - usetesting
-    - varnamelen
-    - wrapcheck
-    - wsl
+    - unused
+  exclusions:
+    generated: lax
+    presets:
+      - comments
+      - common-false-positives
+      - legacy
+      - std-error-handling
+    paths:
+      - validator/web/site_data.go
+      - .*_test.go
+      - proto
+      - tools/analyzers
+      - third_party$
+      - builtin$
+      - examples$
 
-linters-settings:
-  gocognit:
-    # TODO: We should target for < 50
-    min-complexity: 65
-
-output:
-  print-issued-lines: true
-  sort-results: true
+formatters:
+  enable:
+    - gofmt
+    - goimports
+  exclusions:
+    generated: lax
+    paths:
+      - validator/web/site_data.go
+      - .*_test.go
+      - proto
+      - tools/analyzers
+      - third_party$
+      - builtin$
+      - examples$

CHANGELOG.md

@@ -2993,7 +2993,7 @@ There are two known issues with this release:
 
 ### Added
 
-- Web3Signer support. See the [documentation](https://docs.prylabs.network/docs/next/wallet/web3signer) for more
+- Web3Signer support. See the [documentation](https://prysm.offchainlabs.com/docs/manage-wallet/web3signer/) for more
   details.
 - Bellatrix support. See [kiln testnet instructions](https://hackmd.io/OqIoTiQvS9KOIataIFksBQ?view)
 - Weak subjectivity sync / checkpoint sync. This is an experimental feature and may have unintended side effects for

DEPENDENCIES.md

@@ -2,7 +2,7 @@
 
 Prysm is go project with many complicated dependencies, including some c++ based libraries. There
 are two parts to Prysm's dependency management. Go modules and bazel managed dependencies. Be sure 
-to read [Why Bazel?](https://github.com/OffchainLabs/documentation/issues/138) to fully
+to read [Why Bazel?](https://prysm.offchainlabs.com/docs/install-prysm/install-with-bazel/#why-bazel) to fully
 understand the reasoning behind an additional layer of build tooling via Bazel rather than a pure
 "go build" project.
 

WORKSPACE

@@ -158,15 +158,15 @@ oci_register_toolchains(
 
 http_archive(
     name = "io_bazel_rules_go",
-    integrity = "sha256-JD8o94crTb2DFiJJR8nMAGdBAW95zIENB4cbI+JnrI4=",
     patch_args = ["-p1"],
     patches = [
         # Expose internals of go_test for custom build transitions.
         "//third_party:io_bazel_rules_go_test.patch",
     ],
-    strip_prefix = "rules_go-cf3c3af34bd869b864f5f2b98e2f41c2b220d6c9",
+    sha256 = "a729c8ed2447c90fe140077689079ca0acfb7580ec41637f312d650ce9d93d96",
     urls = [
-        "https://github.com/bazel-contrib/rules_go/archive/cf3c3af34bd869b864f5f2b98e2f41c2b220d6c9.tar.gz",
+        "https://mirror.bazel.build/github.com/bazel-contrib/rules_go/releases/download/v0.57.0/rules_go-v0.57.0.zip",
+        "https://github.com/bazel-contrib/rules_go/releases/download/v0.57.0/rules_go-v0.57.0.zip",
     ],
 )
 
@@ -208,7 +208,7 @@ load("@io_bazel_rules_go//go:deps.bzl", "go_register_toolchains", "go_rules_depe
 go_rules_dependencies()
 
 go_register_toolchains(
-    go_version = "1.24.6",
+    go_version = "1.25.1",
     nogo = "@//:nogo",
 )
 
@@ -253,16 +253,16 @@ filegroup(
     url = "https://github.com/ethereum/EIPs/archive/5480440fe51742ed23342b68cf106cefd427e39d.tar.gz",
 )
 
-consensus_spec_version = "v1.6.0-alpha.5"
+consensus_spec_version = "v1.6.0-beta.0"
 
 load("@prysm//tools:download_spectests.bzl", "consensus_spec_tests")
 
 consensus_spec_tests(
     name = "consensus_spec_tests",
     flavors = {
-        "general": "sha256-BXuEb1XbeSft0qzVFnoB8KC0YR1qM3ybT5lKUDbUWn8=",
-        "minimal": "sha256-EjwSHgBbWSoy5hm9V+A/bVMabyojaKsBNPrRtuPVq4k=",
-        "mainnet": "sha256-OGWMzarzaV1B9mVpy48/DCUbhjfX+b64pAxWwPLWhAs=",
+        "general": "sha256-rT3jQp2+ZaDiO66gIQggetzqr+kGeexaLqEhbx4HDMY=",
+        "minimal": "sha256-wowwwyvd0KJLsE+oDOtPkrhZyJndJpJ0lbXYsLH6XBw=",
+        "mainnet": "sha256-4ZLrLNeO7NihZ4TuWH5V5fUhvW9Y3mAPBQDCqrfShps=",
     },
     version = consensus_spec_version,
 )
@@ -278,7 +278,7 @@ filegroup(
     visibility = ["//visibility:public"],
 )
     """,
-    integrity = "sha256-FQWR5EZuVcQGR0ol9vpd7eunnfGexJ/7J3xycrFEJbU=",
+    integrity = "sha256-sBe3Rx8zGq9IrvfgIhZQpYidGjy3mE1SiCb6/+pjLdY=",
     strip_prefix = "consensus-specs-" + consensus_spec_version[1:],
     url = "https://github.com/ethereum/consensus-specs/archive/refs/tags/%s.tar.gz" % consensus_spec_version,
 )
@@ -300,22 +300,6 @@ filegroup(
     url = "https://github.com/ethereum/bls12-381-tests/releases/download/%s/bls_tests_yaml.tar.gz" % bls_test_version,
 )
 
-http_archive(
-    name = "eth2_networks",
-    build_file_content = """
-filegroup(
-    name = "configs",
-    srcs = glob([
-        "shared/**/config.yaml",
-    ]),
-    visibility = ["//visibility:public"],
-)
-    """,
-    sha256 = "77e7e3ed65e33b7bb19d30131f4c2bb39e4dfeb188ab9ae84651c3cc7600131d",
-    strip_prefix = "eth2-networks-934c948e69205dcf2deb87e4ae6cc140c335f94d",
-    url = "https://github.com/eth-clients/eth2-networks/archive/934c948e69205dcf2deb87e4ae6cc140c335f94d.tar.gz",
-)
-
 http_archive(
     name = "holesky_testnet",
     build_file_content = """
@@ -327,9 +311,9 @@ filegroup(
     visibility = ["//visibility:public"],
 )
 """,
-    integrity = "sha256-YVFFrCmjoGZ3fXMWpsCpSsYbANy1grnqYwOLKIg2SsA=",
-    strip_prefix = "holesky-32a72e21c6e53c262f27d50dd540cb654517d03a",
-    url = "https://github.com/eth-clients/holesky/archive/32a72e21c6e53c262f27d50dd540cb654517d03a.tar.gz",  # 2025-03-17
+    integrity = "sha256-htyxg8Ln2o8eCiifFN7/hcHGZg8Ir9CPzCEx+FUnnCs=",
+    strip_prefix = "holesky-8aec65f11f0c986d6b76b2eb902420635eb9b815",
+    url = "https://github.com/eth-clients/holesky/archive/8aec65f11f0c986d6b76b2eb902420635eb9b815.tar.gz",
 )
 
 http_archive(
@@ -359,9 +343,9 @@ filegroup(
     visibility = ["//visibility:public"],
 )
 """,
-    integrity = "sha256-b5F7Wg9LLMqGRIpP2uqb/YsSFVn2ynzlV7g/Nb1EFLk=",
-    strip_prefix = "sepolia-562d9938f08675e9ba490a1dfba21fb05843f39f",
-    url = "https://github.com/eth-clients/sepolia/archive/562d9938f08675e9ba490a1dfba21fb05843f39f.tar.gz",  # 2025-03-17
+    integrity = "sha256-+UZgfvBcea0K0sbvAJZOz5ZNmxdWZYbohP38heUuc6w=",
+    strip_prefix = "sepolia-f9158732adb1a2a6440613ad2232eb50e7384c4f",
+    url = "https://github.com/eth-clients/sepolia/archive/f9158732adb1a2a6440613ad2232eb50e7384c4f.tar.gz",
 )
 
 http_archive(
@@ -375,17 +359,17 @@ filegroup(
     visibility = ["//visibility:public"],
 )
 """,
-    integrity = "sha256-dPiEWUd8QvbYGwGtIm0QtCekitVLOLsW5rpQIGzz8PU=",
-    strip_prefix = "hoodi-828c2c940e1141092bd4bb979cef547ea926d272",
-    url = "https://github.com/eth-clients/hoodi/archive/828c2c940e1141092bd4bb979cef547ea926d272.tar.gz",
+    integrity = "sha256-G+4c9c/vci1OyPrQJnQCI+ZCv/E0cWN4hrHDY3i7ns0=",
+    strip_prefix = "hoodi-b6ee51b2045a5e7fe3efac52534f75b080b049c6",
+    url = "https://github.com/eth-clients/hoodi/archive/b6ee51b2045a5e7fe3efac52534f75b080b049c6.tar.gz",
 )
 
 http_archive(
     name = "com_google_protobuf",
-    sha256 = "9bd87b8280ef720d3240514f884e56a712f2218f0d693b48050c836028940a42",
-    strip_prefix = "protobuf-25.1",
+    sha256 = "7c3ebd7aaedd86fa5dc479a0fda803f602caaf78d8aff7ce83b89e1b8ae7442a",
+    strip_prefix = "protobuf-28.3",
     urls = [
-        "https://github.com/protocolbuffers/protobuf/archive/v25.1.tar.gz",
+        "https://github.com/protocolbuffers/protobuf/archive/v28.3.tar.gz",
     ],
 )
 

api/client/builder/client.go

@@ -30,10 +30,11 @@ import (
 )
 
 const (
-	getExecHeaderPath          = "/eth/v1/builder/header/{{.Slot}}/{{.ParentHash}}/{{.Pubkey}}"
-	getStatus                  = "/eth/v1/builder/status"
-	postBlindedBeaconBlockPath = "/eth/v1/builder/blinded_blocks"
-	postRegisterValidatorPath  = "/eth/v1/builder/validators"
+	getExecHeaderPath            = "/eth/v1/builder/header/{{.Slot}}/{{.ParentHash}}/{{.Pubkey}}"
+	getStatus                    = "/eth/v1/builder/status"
+	postBlindedBeaconBlockPath   = "/eth/v1/builder/blinded_blocks"
+	postBlindedBeaconBlockV2Path = "/eth/v2/builder/blinded_blocks"
+	postRegisterValidatorPath    = "/eth/v1/builder/validators"
 )
 
 var (
@@ -512,7 +513,7 @@ func (c *Client) SubmitBlindedBlockPostFulu(ctx context.Context, sb interfaces.R
 	}
 
 	// Post the blinded block - the response should only contain a status code (no payload)
-	_, _, err = c.do(ctx, http.MethodPost, postBlindedBeaconBlockPath, bytes.NewBuffer(body), http.StatusAccepted, postOpts)
+	_, _, err = c.do(ctx, http.MethodPost, postBlindedBeaconBlockV2Path, bytes.NewBuffer(body), http.StatusAccepted, postOpts)
 	if err != nil {
 		return errors.Wrap(err, "error posting the blinded block to the builder api post-Fulu")
 	}

api/client/builder/client_test.go

@@ -1561,7 +1561,7 @@ func TestSubmitBlindedBlockPostFulu(t *testing.T) {
 	t.Run("success", func(t *testing.T) {
 		hc := &http.Client{
 			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
-				require.Equal(t, postBlindedBeaconBlockPath, r.URL.Path)
+				require.Equal(t, postBlindedBeaconBlockV2Path, r.URL.Path)
 				require.Equal(t, "bellatrix", r.Header.Get("Eth-Consensus-Version"))
 				require.Equal(t, api.JsonMediaType, r.Header.Get("Content-Type"))
 				require.Equal(t, api.JsonMediaType, r.Header.Get("Accept"))
@@ -1586,7 +1586,7 @@ func TestSubmitBlindedBlockPostFulu(t *testing.T) {
 	t.Run("success_ssz", func(t *testing.T) {
 		hc := &http.Client{
 			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
-				require.Equal(t, postBlindedBeaconBlockPath, r.URL.Path)
+				require.Equal(t, postBlindedBeaconBlockV2Path, r.URL.Path)
 				require.Equal(t, "bellatrix", r.Header.Get(api.VersionHeader))
 				require.Equal(t, api.OctetStreamMediaType, r.Header.Get("Content-Type"))
 				require.Equal(t, api.OctetStreamMediaType, r.Header.Get("Accept"))
@@ -1612,7 +1612,7 @@ func TestSubmitBlindedBlockPostFulu(t *testing.T) {
 	t.Run("error_response", func(t *testing.T) {
 		hc := &http.Client{
 			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
-				require.Equal(t, postBlindedBeaconBlockPath, r.URL.Path)
+				require.Equal(t, postBlindedBeaconBlockV2Path, r.URL.Path)
 				require.Equal(t, "bellatrix", r.Header.Get("Eth-Consensus-Version"))
 				message := ErrorMessage{
 					Code:    400,

api/server/httprest/options.go

@@ -1,9 +1,8 @@
 package httprest
 
 import (
-	"time"
-
 	"net/http"
+	"time"
 
 	"github.com/OffchainLabs/prysm/v6/api/server/middleware"
 )

api/server/structs/endpoints_beacon.go

@@ -290,3 +290,9 @@ type GetProposerLookaheadResponse struct {
 	Finalized           bool     `json:"finalized"`
 	Data                []string `json:"data"` // validator indexes
 }
+
+type GetBlobsResponse struct {
+	ExecutionOptimistic bool     `json:"execution_optimistic"`
+	Finalized           bool     `json:"finalized"`
+	Data                []string `json:"data"` //blobs
+}

api/server/structs/endpoints_debug.go

@@ -56,3 +56,19 @@ type ForkChoiceNodeExtraData struct {
 	TimeStamp                string `json:"timestamp"`
 	Target                   string `json:"target"`
 }
+
+type GetDebugDataColumnSidecarsResponse struct {
+	Version             string               `json:"version"`
+	ExecutionOptimistic bool                 `json:"execution_optimistic"`
+	Finalized           bool                 `json:"finalized"`
+	Data                []*DataColumnSidecar `json:"data"`
+}
+
+type DataColumnSidecar struct {
+	Index                        string                   `json:"index"`
+	Column                       []string                 `json:"column"`
+	KzgCommitments               []string                 `json:"kzg_commitments"`
+	KzgProofs                    []string                 `json:"kzg_proofs"`
+	SignedBeaconBlockHeader      *SignedBeaconBlockHeader `json:"signed_block_header"`
+	KzgCommitmentsInclusionProof []string                 `json:"kzg_commitments_inclusion_proof"`
+}

beacon-chain/blockchain/BUILD.bazel

@@ -27,7 +27,7 @@ go_library(
         "receive_block.go",
         "receive_data_column.go",
         "service.go",
-        "setup_forchoice.go",
+        "setup_forkchoice.go",
         "tracked_proposer.go",
         "weak_subjectivity_checks.go",
     ],
@@ -50,7 +50,6 @@ go_library(
         "//beacon-chain/core/feed:go_default_library",
         "//beacon-chain/core/feed/state:go_default_library",
         "//beacon-chain/core/helpers:go_default_library",
-        "//beacon-chain/core/light-client:go_default_library",
         "//beacon-chain/core/peerdas:go_default_library",
         "//beacon-chain/core/signing:go_default_library",
         "//beacon-chain/core/time:go_default_library",
@@ -63,6 +62,7 @@ go_library(
         "//beacon-chain/forkchoice:go_default_library",
         "//beacon-chain/forkchoice/doubly-linked-tree:go_default_library",
         "//beacon-chain/forkchoice/types:go_default_library",
+        "//beacon-chain/light-client:go_default_library",
         "//beacon-chain/operations/attestations:go_default_library",
         "//beacon-chain/operations/blstoexec:go_default_library",
         "//beacon-chain/operations/slashings:go_default_library",
@@ -148,7 +148,6 @@ go_test(
         "//beacon-chain/core/blocks:go_default_library",
         "//beacon-chain/core/feed/state:go_default_library",
         "//beacon-chain/core/helpers:go_default_library",
-        "//beacon-chain/core/light-client:go_default_library",
         "//beacon-chain/core/peerdas:go_default_library",
         "//beacon-chain/core/signing:go_default_library",
         "//beacon-chain/core/transition:go_default_library",
@@ -161,6 +160,7 @@ go_test(
         "//beacon-chain/forkchoice:go_default_library",
         "//beacon-chain/forkchoice/doubly-linked-tree:go_default_library",
         "//beacon-chain/forkchoice/types:go_default_library",
+        "//beacon-chain/light-client:go_default_library",
         "//beacon-chain/operations/attestations:go_default_library",
         "//beacon-chain/operations/attestations/kv:go_default_library",
         "//beacon-chain/operations/blstoexec:go_default_library",

beacon-chain/blockchain/execution_engine.go

@@ -16,7 +16,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
 	"github.com/OffchainLabs/prysm/v6/config/features"
 	"github.com/OffchainLabs/prysm/v6/config/params"
-	consensusblocks "github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
+	blocktypes "github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
 	payloadattribute "github.com/OffchainLabs/prysm/v6/consensus-types/payload-attribute"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
@@ -218,24 +218,18 @@ func (s *Service) getPayloadHash(ctx context.Context, root []byte) ([32]byte, er
 
 // notifyNewPayload signals execution engine on a new payload.
 // It returns true if the EL has returned VALID for the block
-func (s *Service) notifyNewPayload(ctx context.Context, preStateVersion int,
-	preStateHeader interfaces.ExecutionData, blk interfaces.ReadOnlySignedBeaconBlock) (bool, error) {
+// stVersion should represent the version of the pre-state; header should also be from the pre-state.
+func (s *Service) notifyNewPayload(ctx context.Context, stVersion int, header interfaces.ExecutionData, blk blocktypes.ROBlock) (bool, error) {
 	ctx, span := trace.StartSpan(ctx, "blockChain.notifyNewPayload")
 	defer span.End()
 
 	// Execution payload is only supported in Bellatrix and beyond. Pre
 	// merge blocks are never optimistic
-	if blk == nil {
-		return false, errors.New("signed beacon block can't be nil")
-	}
-	if preStateVersion < version.Bellatrix {
+	if stVersion < version.Bellatrix {
 		return true, nil
 	}
-	if err := consensusblocks.BeaconBlockIsNil(blk); err != nil {
-		return false, err
-	}
 	body := blk.Block().Body()
-	enabled, err := blocks.IsExecutionEnabledUsingHeader(preStateHeader, body)
+	enabled, err := blocks.IsExecutionEnabledUsingHeader(header, body)
 	if err != nil {
 		return false, errors.Wrap(invalidBlock{error: err}, "could not determine if execution is enabled")
 	}
@@ -268,28 +262,32 @@ func (s *Service) notifyNewPayload(ctx context.Context, preStateVersion int,
 			return false, errors.New("nil execution requests")
 		}
 	}
-	lastValidHash, err = s.cfg.ExecutionEngineCaller.NewPayload(ctx, payload, versionedHashes, parentRoot, requests)
 
-	switch {
-	case err == nil:
+	lastValidHash, err = s.cfg.ExecutionEngineCaller.NewPayload(ctx, payload, versionedHashes, parentRoot, requests)
+	if err == nil {
 		newPayloadValidNodeCount.Inc()
 		return true, nil
-	case errors.Is(err, execution.ErrAcceptedSyncingPayloadStatus):
+	}
+	logFields := logrus.Fields{
+		"slot":             blk.Block().Slot(),
+		"parentRoot":       fmt.Sprintf("%#x", parentRoot),
+		"root":             fmt.Sprintf("%#x", blk.Root()),
+		"payloadBlockHash": fmt.Sprintf("%#x", bytesutil.Trunc(payload.BlockHash())),
+	}
+	if errors.Is(err, execution.ErrAcceptedSyncingPayloadStatus) {
 		newPayloadOptimisticNodeCount.Inc()
-		log.WithFields(logrus.Fields{
-			"slot":             blk.Block().Slot(),
-			"payloadBlockHash": fmt.Sprintf("%#x", bytesutil.Trunc(payload.BlockHash())),
-		}).Info("Called new payload with optimistic block")
+		log.WithFields(logFields).Info("Called new payload with optimistic block")
 		return false, nil
-	case errors.Is(err, execution.ErrInvalidPayloadStatus):
-		lvh := bytesutil.ToBytes32(lastValidHash)
+	}
+	if errors.Is(err, execution.ErrInvalidPayloadStatus) {
+		log.WithFields(logFields).WithError(err).Error("Invalid payload status")
 		return false, invalidBlock{
 			error:         ErrInvalidPayload,
-			lastValidHash: lvh,
+			lastValidHash: bytesutil.ToBytes32(lastValidHash),
 		}
-	default:
-		return false, errors.WithMessage(ErrUndefinedExecutionEngineError, err.Error())
 	}
+	log.WithFields(logFields).WithError(err).Error("Unexpected execution engine error")
+	return false, errors.WithMessage(ErrUndefinedExecutionEngineError, err.Error())
 }
 
 // reportInvalidBlock deals with the event that an invalid block was detected by the execution layer

beacon-chain/blockchain/execution_engine_test.go

@@ -481,33 +481,12 @@ func Test_NotifyNewPayload(t *testing.T) {
 	phase0State, _ := util.DeterministicGenesisState(t, 1)
 	altairState, _ := util.DeterministicGenesisStateAltair(t, 1)
 	bellatrixState, _ := util.DeterministicGenesisStateBellatrix(t, 2)
-	a := &ethpb.SignedBeaconBlockAltair{
-		Block: &ethpb.BeaconBlockAltair{
-			Body: &ethpb.BeaconBlockBodyAltair{},
-		},
-	}
+	a := util.NewBeaconBlockAltair()
 	altairBlk, err := consensusblocks.NewSignedBeaconBlock(a)
 	require.NoError(t, err)
-	blk := &ethpb.SignedBeaconBlockBellatrix{
-		Block: &ethpb.BeaconBlockBellatrix{
-			Slot: 1,
-			Body: &ethpb.BeaconBlockBodyBellatrix{
-				ExecutionPayload: &v1.ExecutionPayload{
-					BlockNumber:   1,
-					ParentHash:    make([]byte, fieldparams.RootLength),
-					FeeRecipient:  make([]byte, fieldparams.FeeRecipientLength),
-					StateRoot:     make([]byte, fieldparams.RootLength),
-					ReceiptsRoot:  make([]byte, fieldparams.RootLength),
-					LogsBloom:     make([]byte, fieldparams.LogsBloomLength),
-					PrevRandao:    make([]byte, fieldparams.RootLength),
-					ExtraData:     make([]byte, 0),
-					BaseFeePerGas: make([]byte, fieldparams.RootLength),
-					BlockHash:     make([]byte, fieldparams.RootLength),
-					Transactions:  make([][]byte, 0),
-				},
-			},
-		},
-	}
+	blk := util.NewBeaconBlockBellatrix()
+	blk.Block.Slot = 1
+	blk.Block.Body.ExecutionPayload.BlockNumber = 1
 	bellatrixBlk, err := consensusblocks.NewSignedBeaconBlock(util.HydrateSignedBeaconBlockBellatrix(blk))
 	require.NoError(t, err)
 	st := params.BeaconConfig().SlotsPerEpoch.Mul(uint64(epochsSinceFinalitySaveHotStateDB))
@@ -544,12 +523,6 @@ func Test_NotifyNewPayload(t *testing.T) {
 			blk:            altairBlk,
 			isValidPayload: true,
 		},
-		{
-			name:           "nil beacon block",
-			postState:      bellatrixState,
-			errString:      "signed beacon block can't be nil",
-			isValidPayload: false,
-		},
 		{
 			name:           "new payload with optimistic block",
 			postState:      bellatrixState,
@@ -576,15 +549,8 @@ func Test_NotifyNewPayload(t *testing.T) {
 			name:      "altair pre state, happy case",
 			postState: bellatrixState,
 			blk: func() interfaces.ReadOnlySignedBeaconBlock {
-				blk := &ethpb.SignedBeaconBlockBellatrix{
-					Block: &ethpb.BeaconBlockBellatrix{
-						Body: &ethpb.BeaconBlockBodyBellatrix{
-							ExecutionPayload: &v1.ExecutionPayload{
-								ParentHash: bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength),
-							},
-						},
-					},
-				}
+				blk := util.NewBeaconBlockBellatrix()
+				blk.Block.Body.ExecutionPayload.ParentHash = bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength)
 				b, err := consensusblocks.NewSignedBeaconBlock(blk)
 				require.NoError(t, err)
 				return b
@@ -595,24 +561,7 @@ func Test_NotifyNewPayload(t *testing.T) {
 			name:      "not at merge transition",
 			postState: bellatrixState,
 			blk: func() interfaces.ReadOnlySignedBeaconBlock {
-				blk := &ethpb.SignedBeaconBlockBellatrix{
-					Block: &ethpb.BeaconBlockBellatrix{
-						Body: &ethpb.BeaconBlockBodyBellatrix{
-							ExecutionPayload: &v1.ExecutionPayload{
-								ParentHash:    make([]byte, fieldparams.RootLength),
-								FeeRecipient:  make([]byte, fieldparams.FeeRecipientLength),
-								StateRoot:     make([]byte, fieldparams.RootLength),
-								ReceiptsRoot:  make([]byte, fieldparams.RootLength),
-								LogsBloom:     make([]byte, fieldparams.LogsBloomLength),
-								PrevRandao:    make([]byte, fieldparams.RootLength),
-								ExtraData:     make([]byte, 0),
-								BaseFeePerGas: make([]byte, fieldparams.RootLength),
-								BlockHash:     make([]byte, fieldparams.RootLength),
-								Transactions:  make([][]byte, 0),
-							},
-						},
-					},
-				}
+				blk := util.NewBeaconBlockBellatrix()
 				b, err := consensusblocks.NewSignedBeaconBlock(blk)
 				require.NoError(t, err)
 				return b
@@ -623,15 +572,8 @@ func Test_NotifyNewPayload(t *testing.T) {
 			name:      "happy case",
 			postState: bellatrixState,
 			blk: func() interfaces.ReadOnlySignedBeaconBlock {
-				blk := &ethpb.SignedBeaconBlockBellatrix{
-					Block: &ethpb.BeaconBlockBellatrix{
-						Body: &ethpb.BeaconBlockBodyBellatrix{
-							ExecutionPayload: &v1.ExecutionPayload{
-								ParentHash: bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength),
-							},
-						},
-					},
-				}
+				blk := util.NewBeaconBlockBellatrix()
+				blk.Block.Body.ExecutionPayload.ParentHash = bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength)
 				b, err := consensusblocks.NewSignedBeaconBlock(blk)
 				require.NoError(t, err)
 				return b
@@ -642,15 +584,8 @@ func Test_NotifyNewPayload(t *testing.T) {
 			name:      "undefined error from ee",
 			postState: bellatrixState,
 			blk: func() interfaces.ReadOnlySignedBeaconBlock {
-				blk := &ethpb.SignedBeaconBlockBellatrix{
-					Block: &ethpb.BeaconBlockBellatrix{
-						Body: &ethpb.BeaconBlockBodyBellatrix{
-							ExecutionPayload: &v1.ExecutionPayload{
-								ParentHash: bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength),
-							},
-						},
-					},
-				}
+				blk := util.NewBeaconBlockBellatrix()
+				blk.Block.Body.ExecutionPayload.ParentHash = bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength)
 				b, err := consensusblocks.NewSignedBeaconBlock(blk)
 				require.NoError(t, err)
 				return b
@@ -662,15 +597,8 @@ func Test_NotifyNewPayload(t *testing.T) {
 			name:      "invalid block hash error from ee",
 			postState: bellatrixState,
 			blk: func() interfaces.ReadOnlySignedBeaconBlock {
-				blk := &ethpb.SignedBeaconBlockBellatrix{
-					Block: &ethpb.BeaconBlockBellatrix{
-						Body: &ethpb.BeaconBlockBodyBellatrix{
-							ExecutionPayload: &v1.ExecutionPayload{
-								ParentHash: bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength),
-							},
-						},
-					},
-				}
+				blk := util.NewBeaconBlockBellatrix()
+				blk.Block.Body.ExecutionPayload.ParentHash = bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength)
 				b, err := consensusblocks.NewSignedBeaconBlock(blk)
 				require.NoError(t, err)
 				return b
@@ -701,7 +629,9 @@ func Test_NotifyNewPayload(t *testing.T) {
 			require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, state, blkRoot))
 			postVersion, postHeader, err := getStateVersionAndPayload(tt.postState)
 			require.NoError(t, err)
-			isValidPayload, err := service.notifyNewPayload(ctx, postVersion, postHeader, tt.blk)
+			rob, err := consensusblocks.NewROBlock(tt.blk)
+			require.NoError(t, err)
+			isValidPayload, err := service.notifyNewPayload(ctx, postVersion, postHeader, rob)
 			if tt.errString != "" {
 				require.ErrorContains(t, tt.errString, err)
 				if tt.invalidBlock {
@@ -725,17 +655,12 @@ func Test_NotifyNewPayload_SetOptimisticToValid(t *testing.T) {
 	ctx := tr.ctx
 
 	bellatrixState, _ := util.DeterministicGenesisStateBellatrix(t, 2)
-	blk := &ethpb.SignedBeaconBlockBellatrix{
-		Block: &ethpb.BeaconBlockBellatrix{
-			Body: &ethpb.BeaconBlockBodyBellatrix{
-				ExecutionPayload: &v1.ExecutionPayload{
-					ParentHash: bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength),
-				},
-			},
-		},
-	}
+	blk := util.NewBeaconBlockBellatrix()
+	blk.Block.Body.ExecutionPayload.ParentHash = bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength)
 	bellatrixBlk, err := consensusblocks.NewSignedBeaconBlock(blk)
 	require.NoError(t, err)
+	rob, err := consensusblocks.NewROBlock(bellatrixBlk)
+	require.NoError(t, err)
 	e := &mockExecution.EngineClient{BlockByHashMap: map[[32]byte]*v1.ExecutionBlock{}}
 	e.BlockByHashMap[[32]byte{'a'}] = &v1.ExecutionBlock{
 		Header: gethtypes.Header{
@@ -752,7 +677,7 @@ func Test_NotifyNewPayload_SetOptimisticToValid(t *testing.T) {
 	service.cfg.ExecutionEngineCaller = e
 	postVersion, postHeader, err := getStateVersionAndPayload(bellatrixState)
 	require.NoError(t, err)
-	validated, err := service.notifyNewPayload(ctx, postVersion, postHeader, bellatrixBlk)
+	validated, err := service.notifyNewPayload(ctx, postVersion, postHeader, rob)
 	require.NoError(t, err)
 	require.Equal(t, true, validated)
 }

beacon-chain/blockchain/kzg/kzg.go

@@ -14,7 +14,10 @@ const BytesPerBlob = ckzg4844.BytesPerBlob
 type Blob [BytesPerBlob]byte
 
 // BytesPerCell is the number of bytes in a single cell.
-const BytesPerCell = ckzg4844.BytesPerCell
+const (
+	BytesPerCell  = ckzg4844.BytesPerCell
+	BytesPerProof = ckzg4844.BytesPerProof
+)
 
 // Cell represents a chunk of an encoded Blob.
 type Cell [BytesPerCell]byte
@@ -23,7 +26,7 @@ type Cell [BytesPerCell]byte
 type Commitment [48]byte
 
 // Proof represents a KZG proof that attests to the validity of a Blob or parts of it.
-type Proof [48]byte
+type Proof [BytesPerProof]byte
 
 // Bytes48 is a 48-byte array.
 type Bytes48 = ckzg4844.Bytes48
@@ -102,7 +105,6 @@ func VerifyCellKZGProofBatch(commitmentsBytes []Bytes48, cellIndices []uint64, c
 	for i := range cells {
 		ckzgCells[i] = ckzg4844.Cell(cells[i])
 	}
-
 	return ckzg4844.VerifyCellKZGProofBatch(commitmentsBytes, cellIndices, ckzgCells, proofsBytes)
 }
 

beacon-chain/blockchain/kzg/validation.go

@@ -1,10 +1,30 @@
 package kzg
 
 import (
+	"fmt"
+
 	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
 	GoKZG "github.com/crate-crypto/go-kzg-4844"
+	ckzg4844 "github.com/ethereum/c-kzg-4844/v2/bindings/go"
+	"github.com/pkg/errors"
 )
 
+func bytesToBlob(blob []byte) *GoKZG.Blob {
+	var ret GoKZG.Blob
+	copy(ret[:], blob)
+	return &ret
+}
+
+func bytesToCommitment(commitment []byte) (ret GoKZG.KZGCommitment) {
+	copy(ret[:], commitment)
+	return
+}
+
+func bytesToKZGProof(proof []byte) (ret GoKZG.KZGProof) {
+	copy(ret[:], proof)
+	return
+}
+
 // Verify performs single or batch verification of commitments depending on the number of given BlobSidecars.
 func Verify(blobSidecars ...blocks.ROBlob) error {
 	if len(blobSidecars) == 0 {
@@ -27,18 +47,121 @@ func Verify(blobSidecars ...blocks.ROBlob) error {
 	return kzgContext.VerifyBlobKZGProofBatch(blobs, cmts, proofs)
 }
 
-func bytesToBlob(blob []byte) *GoKZG.Blob {
-	var ret GoKZG.Blob
-	copy(ret[:], blob)
-	return &ret
+// VerifyBlobKZGProofBatch verifies KZG proofs for multiple blobs using batch verification.
+// This is more efficient than verifying each blob individually when len(blobs) > 1.
+// For single blob verification, it uses the optimized single verification path.
+func VerifyBlobKZGProofBatch(blobs [][]byte, commitments [][]byte, proofs [][]byte) error {
+	if len(blobs) != len(commitments) || len(blobs) != len(proofs) {
+		return errors.Errorf("number of blobs (%d), commitments (%d), and proofs (%d) must match", len(blobs), len(commitments), len(proofs))
+	}
+
+	if len(blobs) == 0 {
+		return nil
+	}
+
+	// Optimize for single blob case - use single verification to avoid batch overhead
+	if len(blobs) == 1 {
+		return kzgContext.VerifyBlobKZGProof(
+			bytesToBlob(blobs[0]),
+			bytesToCommitment(commitments[0]),
+			bytesToKZGProof(proofs[0]))
+	}
+
+	// Use batch verification for multiple blobs
+	ckzgBlobs := make([]ckzg4844.Blob, len(blobs))
+	ckzgCommitments := make([]ckzg4844.Bytes48, len(commitments))
+	ckzgProofs := make([]ckzg4844.Bytes48, len(proofs))
+
+	for i := range blobs {
+		if len(blobs[i]) != len(ckzg4844.Blob{}) {
+			return fmt.Errorf("blobs len (%d) differs from expected (%d)", len(blobs[i]), len(ckzg4844.Blob{}))
+		}
+		if len(commitments[i]) != len(ckzg4844.Bytes48{}) {
+			return fmt.Errorf("commitments len (%d) differs from expected (%d)", len(commitments[i]), len(ckzg4844.Blob{}))
+		}
+		if len(proofs[i]) != len(ckzg4844.Bytes48{}) {
+			return fmt.Errorf("proofs len (%d) differs from expected (%d)", len(proofs[i]), len(ckzg4844.Blob{}))
+		}
+		ckzgBlobs[i] = ckzg4844.Blob(blobs[i])
+		ckzgCommitments[i] = ckzg4844.Bytes48(commitments[i])
+		ckzgProofs[i] = ckzg4844.Bytes48(proofs[i])
+	}
+
+	valid, err := ckzg4844.VerifyBlobKZGProofBatch(ckzgBlobs, ckzgCommitments, ckzgProofs)
+	if err != nil {
+		return errors.Wrap(err, "batch verification")
+	}
+	if !valid {
+		return errors.New("batch KZG proof verification failed")
+	}
+
+	return nil
 }
 
-func bytesToCommitment(commitment []byte) (ret GoKZG.KZGCommitment) {
-	copy(ret[:], commitment)
-	return
-}
+// VerifyCellKZGProofBatchFromBlobData verifies cell KZG proofs in batch format directly from blob data.
+// This is more efficient than reconstructing data column sidecars when you have the raw blob data and cell proofs.
+// For PeerDAS/Fulu, the execution client provides cell proofs in flattened format via BlobsBundleV2.
+// For single blob verification, it optimizes by computing cells once and verifying efficiently.
+func VerifyCellKZGProofBatchFromBlobData(blobs [][]byte, commitments [][]byte, cellProofs [][]byte, numberOfColumns uint64) error {
+	blobCount := uint64(len(blobs))
+	expectedCellProofs := blobCount * numberOfColumns
 
-func bytesToKZGProof(proof []byte) (ret GoKZG.KZGProof) {
-	copy(ret[:], proof)
-	return
+	if uint64(len(cellProofs)) != expectedCellProofs {
+		return errors.Errorf("expected %d cell proofs, got %d", expectedCellProofs, len(cellProofs))
+	}
+
+	if len(commitments) != len(blobs) {
+		return errors.Errorf("number of commitments (%d) must match number of blobs (%d)", len(commitments), len(blobs))
+	}
+
+	if blobCount == 0 {
+		return nil
+	}
+
+	// Handle multiple blobs - compute cells for all blobs
+	allCells := make([]Cell, 0, expectedCellProofs)
+	allCommitments := make([]Bytes48, 0, expectedCellProofs)
+	allIndices := make([]uint64, 0, expectedCellProofs)
+	allProofs := make([]Bytes48, 0, expectedCellProofs)
+
+	for blobIndex := range blobs {
+		if len(blobs[blobIndex]) != len(Blob{}) {
+			return fmt.Errorf("blobs len (%d) differs from expected (%d)", len(blobs[blobIndex]), len(Blob{}))
+		}
+		// Convert blob to kzg.Blob type
+		blob := Blob(blobs[blobIndex])
+
+		// Compute cells for this blob
+		cells, err := ComputeCells(&blob)
+		if err != nil {
+			return errors.Wrapf(err, "failed to compute cells for blob %d", blobIndex)
+		}
+
+		// Add cells and corresponding data for each column
+		for columnIndex := range numberOfColumns {
+			cellProofIndex := uint64(blobIndex)*numberOfColumns + columnIndex
+			if len(commitments[blobIndex]) != len(Bytes48{}) {
+				return fmt.Errorf("commitments len (%d) differs from expected (%d)", len(commitments[blobIndex]), len(Bytes48{}))
+			}
+			if len(cellProofs[cellProofIndex]) != len(Bytes48{}) {
+				return fmt.Errorf("proofs len (%d) differs from expected (%d)", len(cellProofs[cellProofIndex]), len(Bytes48{}))
+			}
+			allCells = append(allCells, cells[columnIndex])
+			allCommitments = append(allCommitments, Bytes48(commitments[blobIndex]))
+			allIndices = append(allIndices, columnIndex)
+
+			allProofs = append(allProofs, Bytes48(cellProofs[cellProofIndex]))
+		}
+	}
+
+	// Batch verify all cells
+	valid, err := VerifyCellKZGProofBatch(allCommitments, allIndices, allCells, allProofs)
+	if err != nil {
+		return errors.Wrap(err, "cell batch verification")
+	}
+	if !valid {
+		return errors.New("cell KZG proof batch verification failed")
+	}
+
+	return nil
 }

beacon-chain/blockchain/kzg/validation_test.go

@@ -37,6 +37,7 @@ func TestBytesToAny(t *testing.T) {
 }
 
 func TestGenerateCommitmentAndProof(t *testing.T) {
+	require.NoError(t, Start())
 	blob := random.GetRandBlob(123)
 	commitment, proof, err := GenerateCommitmentAndProof(blob)
 	require.NoError(t, err)
@@ -45,3 +46,432 @@ func TestGenerateCommitmentAndProof(t *testing.T) {
 	require.Equal(t, expectedCommitment, commitment)
 	require.Equal(t, expectedProof, proof)
 }
+
+func TestVerifyBlobKZGProofBatch(t *testing.T) {
+	// Initialize KZG for testing
+	require.NoError(t, Start())
+
+	t.Run("valid single blob batch", func(t *testing.T) {
+		blob := random.GetRandBlob(123)
+		commitment, proof, err := GenerateCommitmentAndProof(blob)
+		require.NoError(t, err)
+
+		blobs := [][]byte{blob[:]}
+		commitments := [][]byte{commitment[:]}
+		proofs := [][]byte{proof[:]}
+
+		err = VerifyBlobKZGProofBatch(blobs, commitments, proofs)
+		require.NoError(t, err)
+	})
+
+	t.Run("valid multiple blob batch", func(t *testing.T) {
+		blobCount := 3
+		blobs := make([][]byte, blobCount)
+		commitments := make([][]byte, blobCount)
+		proofs := make([][]byte, blobCount)
+
+		for i := 0; i < blobCount; i++ {
+			blob := random.GetRandBlob(int64(i))
+			commitment, proof, err := GenerateCommitmentAndProof(blob)
+			require.NoError(t, err)
+
+			blobs[i] = blob[:]
+			commitments[i] = commitment[:]
+			proofs[i] = proof[:]
+		}
+
+		err := VerifyBlobKZGProofBatch(blobs, commitments, proofs)
+		require.NoError(t, err)
+	})
+
+	t.Run("empty inputs should pass", func(t *testing.T) {
+		err := VerifyBlobKZGProofBatch([][]byte{}, [][]byte{}, [][]byte{})
+		require.NoError(t, err)
+	})
+
+	t.Run("mismatched input lengths", func(t *testing.T) {
+		blob := random.GetRandBlob(123)
+		commitment, proof, err := GenerateCommitmentAndProof(blob)
+		require.NoError(t, err)
+
+		// Test different mismatch scenarios
+		err = VerifyBlobKZGProofBatch(
+			[][]byte{blob[:]},
+			[][]byte{},
+			[][]byte{proof[:]},
+		)
+		require.ErrorContains(t, "number of blobs (1), commitments (0), and proofs (1) must match", err)
+
+		err = VerifyBlobKZGProofBatch(
+			[][]byte{blob[:], blob[:]},
+			[][]byte{commitment[:]},
+			[][]byte{proof[:], proof[:]},
+		)
+		require.ErrorContains(t, "number of blobs (2), commitments (1), and proofs (2) must match", err)
+	})
+
+	t.Run("invalid commitment should fail", func(t *testing.T) {
+		blob := random.GetRandBlob(123)
+		_, proof, err := GenerateCommitmentAndProof(blob)
+		require.NoError(t, err)
+
+		// Use a different blob's commitment (mismatch)
+		differentBlob := random.GetRandBlob(456)
+		wrongCommitment, _, err := GenerateCommitmentAndProof(differentBlob)
+		require.NoError(t, err)
+
+		blobs := [][]byte{blob[:]}
+		commitments := [][]byte{wrongCommitment[:]}
+		proofs := [][]byte{proof[:]}
+
+		err = VerifyBlobKZGProofBatch(blobs, commitments, proofs)
+		// Single blob optimization uses different error message
+		require.ErrorContains(t, "can't verify opening proof", err)
+	})
+
+	t.Run("invalid proof should fail", func(t *testing.T) {
+		blob := random.GetRandBlob(123)
+		commitment, _, err := GenerateCommitmentAndProof(blob)
+		require.NoError(t, err)
+
+		// Use wrong proof
+		invalidProof := make([]byte, 48) // All zeros
+
+		blobs := [][]byte{blob[:]}
+		commitments := [][]byte{commitment[:]}
+		proofs := [][]byte{invalidProof}
+
+		err = VerifyBlobKZGProofBatch(blobs, commitments, proofs)
+		require.ErrorContains(t, "short buffer", err)
+	})
+
+	t.Run("mixed valid and invalid proofs should fail", func(t *testing.T) {
+		// First blob - valid
+		blob1 := random.GetRandBlob(123)
+		commitment1, proof1, err := GenerateCommitmentAndProof(blob1)
+		require.NoError(t, err)
+
+		// Second blob - invalid proof
+		blob2 := random.GetRandBlob(456)
+		commitment2, _, err := GenerateCommitmentAndProof(blob2)
+		require.NoError(t, err)
+		invalidProof := make([]byte, 48) // All zeros
+
+		blobs := [][]byte{blob1[:], blob2[:]}
+		commitments := [][]byte{commitment1[:], commitment2[:]}
+		proofs := [][]byte{proof1[:], invalidProof}
+
+		err = VerifyBlobKZGProofBatch(blobs, commitments, proofs)
+		require.ErrorContains(t, "batch verification", err)
+	})
+
+	t.Run("batch KZG proof verification failed", func(t *testing.T) {
+		// Create multiple blobs with mismatched commitments and proofs to trigger batch verification failure
+		blob1 := random.GetRandBlob(123)
+		blob2 := random.GetRandBlob(456)
+
+		// Generate valid proof for blob1
+		commitment1, proof1, err := GenerateCommitmentAndProof(blob1)
+		require.NoError(t, err)
+
+		// Generate valid proof for blob2 but use wrong commitment (from blob1)
+		_, proof2, err := GenerateCommitmentAndProof(blob2)
+		require.NoError(t, err)
+
+		// Use blob2 data with blob1's commitment and blob2's proof - this should cause batch verification to fail
+		blobs := [][]byte{blob1[:], blob2[:]}
+		commitments := [][]byte{commitment1[:], commitment1[:]} // Wrong commitment for blob2
+		proofs := [][]byte{proof1[:], proof2[:]}
+
+		err = VerifyBlobKZGProofBatch(blobs, commitments, proofs)
+		require.ErrorContains(t, "batch KZG proof verification failed", err)
+	})
+}
+
+func TestVerifyCellKZGProofBatchFromBlobData(t *testing.T) {
+	// Initialize KZG for testing
+	require.NoError(t, Start())
+
+	t.Run("valid single blob cell verification", func(t *testing.T) {
+		numberOfColumns := uint64(128)
+
+		// Generate blob and commitment
+		randBlob := random.GetRandBlob(123)
+		var blob Blob
+		copy(blob[:], randBlob[:])
+		commitment, err := BlobToKZGCommitment(&blob)
+		require.NoError(t, err)
+
+		// Compute cells and proofs
+		cellsAndProofs, err := ComputeCellsAndKZGProofs(&blob)
+		require.NoError(t, err)
+
+		// Create flattened cell proofs (like execution client format)
+		cellProofs := make([][]byte, numberOfColumns)
+		for i := range numberOfColumns {
+			cellProofs[i] = cellsAndProofs.Proofs[i][:]
+		}
+
+		blobs := [][]byte{blob[:]}
+		commitments := [][]byte{commitment[:]}
+
+		err = VerifyCellKZGProofBatchFromBlobData(blobs, commitments, cellProofs, numberOfColumns)
+		require.NoError(t, err)
+	})
+
+	t.Run("valid multiple blob cell verification", func(t *testing.T) {
+		numberOfColumns := uint64(128)
+		blobCount := 2
+
+		blobs := make([][]byte, blobCount)
+		commitments := make([][]byte, blobCount)
+		var allCellProofs [][]byte
+
+		for i := range blobCount {
+			// Generate blob and commitment
+			randBlob := random.GetRandBlob(int64(i))
+			var blob Blob
+			copy(blob[:], randBlob[:])
+			commitment, err := BlobToKZGCommitment(&blob)
+			require.NoError(t, err)
+
+			// Compute cells and proofs
+			cellsAndProofs, err := ComputeCellsAndKZGProofs(&blob)
+			require.NoError(t, err)
+
+			blobs[i] = blob[:]
+			commitments[i] = commitment[:]
+
+			// Add cell proofs for this blob
+			for j := range numberOfColumns {
+				allCellProofs = append(allCellProofs, cellsAndProofs.Proofs[j][:])
+			}
+		}
+
+		err := VerifyCellKZGProofBatchFromBlobData(blobs, commitments, allCellProofs, numberOfColumns)
+		require.NoError(t, err)
+	})
+
+	t.Run("empty inputs should pass", func(t *testing.T) {
+		err := VerifyCellKZGProofBatchFromBlobData([][]byte{}, [][]byte{}, [][]byte{}, 128)
+		require.NoError(t, err)
+	})
+
+	t.Run("mismatched blob and commitment count", func(t *testing.T) {
+		randBlob := random.GetRandBlob(123)
+		var blob Blob
+		copy(blob[:], randBlob[:])
+
+		err := VerifyCellKZGProofBatchFromBlobData(
+			[][]byte{blob[:]},
+			[][]byte{}, // Empty commitments
+			[][]byte{},
+			128,
+		)
+		require.ErrorContains(t, "expected 128 cell proofs", err)
+	})
+
+	t.Run("wrong cell proof count", func(t *testing.T) {
+		numberOfColumns := uint64(128)
+
+		randBlob := random.GetRandBlob(123)
+		var blob Blob
+		copy(blob[:], randBlob[:])
+		commitment, err := BlobToKZGCommitment(&blob)
+		require.NoError(t, err)
+
+		blobs := [][]byte{blob[:]}
+		commitments := [][]byte{commitment[:]}
+
+		// Wrong number of cell proofs - should be 128 for 1 blob, but provide 10
+		wrongCellProofs := make([][]byte, 10)
+
+		err = VerifyCellKZGProofBatchFromBlobData(blobs, commitments, wrongCellProofs, numberOfColumns)
+		require.ErrorContains(t, "expected 128 cell proofs, got 10", err)
+	})
+
+	t.Run("invalid cell proofs should fail", func(t *testing.T) {
+		numberOfColumns := uint64(128)
+
+		randBlob := random.GetRandBlob(123)
+		var blob Blob
+		copy(blob[:], randBlob[:])
+		commitment, err := BlobToKZGCommitment(&blob)
+		require.NoError(t, err)
+
+		blobs := [][]byte{blob[:]}
+		commitments := [][]byte{commitment[:]}
+
+		// Create invalid cell proofs (all zeros)
+		invalidCellProofs := make([][]byte, numberOfColumns)
+		for i := range numberOfColumns {
+			invalidCellProofs[i] = make([]byte, 48) // All zeros
+		}
+
+		err = VerifyCellKZGProofBatchFromBlobData(blobs, commitments, invalidCellProofs, numberOfColumns)
+		require.ErrorContains(t, "cell batch verification", err)
+	})
+
+	t.Run("mismatched commitment should fail", func(t *testing.T) {
+		numberOfColumns := uint64(128)
+
+		// Generate blob and correct cell proofs
+		randBlob := random.GetRandBlob(123)
+		var blob Blob
+		copy(blob[:], randBlob[:])
+		cellsAndProofs, err := ComputeCellsAndKZGProofs(&blob)
+		require.NoError(t, err)
+
+		// Generate wrong commitment from different blob
+		randBlob2 := random.GetRandBlob(456)
+		var differentBlob Blob
+		copy(differentBlob[:], randBlob2[:])
+		wrongCommitment, err := BlobToKZGCommitment(&differentBlob)
+		require.NoError(t, err)
+
+		cellProofs := make([][]byte, numberOfColumns)
+		for i := range numberOfColumns {
+			cellProofs[i] = cellsAndProofs.Proofs[i][:]
+		}
+
+		blobs := [][]byte{blob[:]}
+		commitments := [][]byte{wrongCommitment[:]}
+
+		err = VerifyCellKZGProofBatchFromBlobData(blobs, commitments, cellProofs, numberOfColumns)
+		require.ErrorContains(t, "cell KZG proof batch verification failed", err)
+	})
+
+	t.Run("invalid blob data that should cause ComputeCells to fail", func(t *testing.T) {
+		numberOfColumns := uint64(128)
+
+		// Create invalid blob (not properly formatted)
+		invalidBlobData := make([]byte, 10) // Too short
+		commitment := make([]byte, 48)      // Dummy commitment
+		cellProofs := make([][]byte, numberOfColumns)
+		for i := range numberOfColumns {
+			cellProofs[i] = make([]byte, 48)
+		}
+
+		blobs := [][]byte{invalidBlobData}
+		commitments := [][]byte{commitment}
+
+		err := VerifyCellKZGProofBatchFromBlobData(blobs, commitments, cellProofs, numberOfColumns)
+		require.NotNil(t, err)
+		require.ErrorContains(t, "blobs len (10) differs from expected (131072)", err)
+	})
+
+	t.Run("invalid commitment size should fail", func(t *testing.T) {
+		numberOfColumns := uint64(128)
+
+		randBlob := random.GetRandBlob(123)
+		var blob Blob
+		copy(blob[:], randBlob[:])
+
+		// Create invalid commitment (wrong size)
+		invalidCommitment := make([]byte, 32) // Should be 48 bytes
+		cellProofs := make([][]byte, numberOfColumns)
+		for i := range numberOfColumns {
+			cellProofs[i] = make([]byte, 48)
+		}
+
+		blobs := [][]byte{blob[:]}
+		commitments := [][]byte{invalidCommitment}
+
+		err := VerifyCellKZGProofBatchFromBlobData(blobs, commitments, cellProofs, numberOfColumns)
+		require.ErrorContains(t, "commitments len (32) differs from expected (48)", err)
+	})
+
+	t.Run("invalid cell proof size should fail", func(t *testing.T) {
+		numberOfColumns := uint64(128)
+
+		randBlob := random.GetRandBlob(123)
+		var blob Blob
+		copy(blob[:], randBlob[:])
+		commitment, err := BlobToKZGCommitment(&blob)
+		require.NoError(t, err)
+
+		// Create invalid cell proofs (wrong size)
+		invalidCellProofs := make([][]byte, numberOfColumns)
+		for i := range numberOfColumns {
+			if i == 0 {
+				invalidCellProofs[i] = make([]byte, 32) // Wrong size - should be 48
+			} else {
+				invalidCellProofs[i] = make([]byte, 48)
+			}
+		}
+
+		blobs := [][]byte{blob[:]}
+		commitments := [][]byte{commitment[:]}
+
+		err = VerifyCellKZGProofBatchFromBlobData(blobs, commitments, invalidCellProofs, numberOfColumns)
+		require.ErrorContains(t, "proofs len (32) differs from expected (48)", err)
+	})
+
+	t.Run("multiple blobs with mixed invalid commitments", func(t *testing.T) {
+		numberOfColumns := uint64(128)
+		blobCount := 2
+
+		blobs := make([][]byte, blobCount)
+		commitments := make([][]byte, blobCount)
+		var allCellProofs [][]byte
+
+		// First blob - valid
+		randBlob1 := random.GetRandBlob(123)
+		var blob1 Blob
+		copy(blob1[:], randBlob1[:])
+		commitment1, err := BlobToKZGCommitment(&blob1)
+		require.NoError(t, err)
+		blobs[0] = blob1[:]
+		commitments[0] = commitment1[:]
+
+		// Second blob - use invalid commitment size
+		randBlob2 := random.GetRandBlob(456)
+		var blob2 Blob
+		copy(blob2[:], randBlob2[:])
+		blobs[1] = blob2[:]
+		commitments[1] = make([]byte, 32) // Wrong size
+
+		// Add cell proofs for both blobs
+		for i := 0; i < blobCount; i++ {
+			for j := uint64(0); j < numberOfColumns; j++ {
+				allCellProofs = append(allCellProofs, make([]byte, 48))
+			}
+		}
+
+		err = VerifyCellKZGProofBatchFromBlobData(blobs, commitments, allCellProofs, numberOfColumns)
+		require.ErrorContains(t, "commitments len (32) differs from expected (48)", err)
+	})
+
+	t.Run("multiple blobs with mixed invalid cell proof sizes", func(t *testing.T) {
+		numberOfColumns := uint64(128)
+		blobCount := 2
+
+		blobs := make([][]byte, blobCount)
+		commitments := make([][]byte, blobCount)
+		var allCellProofs [][]byte
+
+		for i := 0; i < blobCount; i++ {
+			randBlob := random.GetRandBlob(int64(i))
+			var blob Blob
+			copy(blob[:], randBlob[:])
+			commitment, err := BlobToKZGCommitment(&blob)
+			require.NoError(t, err)
+
+			blobs[i] = blob[:]
+			commitments[i] = commitment[:]
+
+			// Add cell proofs - make some invalid in the second blob
+			for j := uint64(0); j < numberOfColumns; j++ {
+				if i == 1 && j == 64 {
+					// Invalid proof size in middle of second blob's proofs
+					allCellProofs = append(allCellProofs, make([]byte, 20))
+				} else {
+					allCellProofs = append(allCellProofs, make([]byte, 48))
+				}
+			}
+		}
+
+		err := VerifyCellKZGProofBatchFromBlobData(blobs, commitments, allCellProofs, numberOfColumns)
+		require.ErrorContains(t, "proofs len (20) differs from expected (48)", err)
+	})
+}

beacon-chain/blockchain/options.go

@@ -6,11 +6,11 @@ import (
 	"github.com/OffchainLabs/prysm/v6/async/event"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/cache"
 	statefeed "github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed/state"
-	lightclient "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filesystem"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/execution"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/forkchoice"
+	lightclient "github.com/OffchainLabs/prysm/v6/beacon-chain/light-client"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/operations/attestations"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/operations/blstoexec"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/operations/slashings"
@@ -35,7 +35,7 @@ func WithMaxGoroutines(x int) Option {
 // WithLCStore for light client store access.
 func WithLCStore() Option {
 	return func(s *Service) error {
-		s.lcStore = lightclient.NewLightClientStore(s.cfg.BeaconDB, s.cfg.P2P, s.cfg.StateNotifier.StateFeed())
+		s.lcStore = lightclient.NewLightClientStore(s.cfg.P2P, s.cfg.StateNotifier.StateFeed(), s.cfg.BeaconDB)
 		return nil
 	}
 }

beacon-chain/blockchain/process_block.go

@@ -3,7 +3,6 @@ package blockchain
 import (
 	"context"
 	"fmt"
-	"slices"
 	"time"
 
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/blocks"
@@ -159,7 +158,7 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []consensusblocks.ROBlo
 	}
 
 	// Fill in missing blocks
-	if err := s.fillInForkChoiceMissingBlocks(ctx, blks[0], preState.CurrentJustifiedCheckpoint(), preState.FinalizedCheckpoint()); err != nil {
+	if err := s.fillInForkChoiceMissingBlocks(ctx, blks[0], preState.FinalizedCheckpoint(), preState.CurrentJustifiedCheckpoint()); err != nil {
 		return errors.Wrap(err, "could not fill in missing blocks to forkchoice")
 	}
 
@@ -247,7 +246,7 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []consensusblocks.ROBlo
 		args := &forkchoicetypes.BlockAndCheckpoints{Block: b,
 			JustifiedCheckpoint: jCheckpoints[i],
 			FinalizedCheckpoint: fCheckpoints[i]}
-		pendingNodes[len(blks)-i-1] = args
+		pendingNodes[i] = args
 		if err := s.saveInitSyncBlock(ctx, root, b); err != nil {
 			tracing.AnnotateError(span, err)
 			return err
@@ -284,14 +283,10 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []consensusblocks.ROBlo
 	if err := s.cfg.StateGen.SaveState(ctx, lastBR, preState); err != nil {
 		return err
 	}
-	// Insert all nodes but the last one to forkchoice
+	// Insert all nodes to forkchoice
 	if err := s.cfg.ForkChoiceStore.InsertChain(ctx, pendingNodes); err != nil {
 		return errors.Wrap(err, "could not insert batch to forkchoice")
 	}
-	// Insert the last block to forkchoice
-	if err := s.cfg.ForkChoiceStore.InsertNode(ctx, preState, lastB); err != nil {
-		return errors.Wrap(err, "could not insert last block in batch to forkchoice")
-	}
 	// Set their optimistic status
 	if isValidPayload {
 		if err := s.cfg.ForkChoiceStore.SetOptimisticToValid(ctx, lastBR); err != nil {
@@ -664,14 +659,14 @@ func missingDataColumnIndices(store *filesystem.DataColumnStorage, root [fieldpa
 // closed, the context hits cancellation/timeout, or notifications have been received for all the missing sidecars.
 func (s *Service) isDataAvailable(
 	ctx context.Context,
-	root [fieldparams.RootLength]byte,
-	signedBlock interfaces.ReadOnlySignedBeaconBlock,
+	roBlock consensusblocks.ROBlock,
 ) error {
-	block := signedBlock.Block()
+	block := roBlock.Block()
 	if block == nil {
 		return errors.New("invalid nil beacon block")
 	}
 
+	root := roBlock.Root()
 	blockVersion := block.Version()
 	if blockVersion >= version.Fulu {
 		return s.areDataColumnsAvailable(ctx, root, block)
@@ -691,8 +686,6 @@ func (s *Service) areDataColumnsAvailable(
 	root [fieldparams.RootLength]byte,
 	block interfaces.ReadOnlyBeaconBlock,
 ) error {
-	samplesPerSlot := params.BeaconConfig().SamplesPerSlot
-
 	// We are only required to check within MIN_EPOCHS_FOR_DATA_COLUMN_SIDECARS_REQUESTS
 	blockSlot, currentSlot := block.Slot(), s.CurrentSlot()
 	blockEpoch, currentEpoch := slots.ToEpoch(blockSlot), slots.ToEpoch(currentSlot)
@@ -726,6 +719,7 @@ func (s *Service) areDataColumnsAvailable(
 
 	// Compute the sampling size.
 	// https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/das-core.md#custody-sampling
+	samplesPerSlot := params.BeaconConfig().SamplesPerSlot
 	samplingSize := max(samplesPerSlot, custodyGroupCount)
 
 	// Get the peer info for the node.
@@ -751,14 +745,14 @@ func (s *Service) areDataColumnsAvailable(
 	}
 
 	// Get a map of data column indices that are not currently available.
-	missingMap, err := missingDataColumnIndices(s.dataColumnStorage, root, peerInfo.CustodyColumns)
+	missing, err := missingDataColumnIndices(s.dataColumnStorage, root, peerInfo.CustodyColumns)
 	if err != nil {
 		return errors.Wrap(err, "missing data columns")
 	}
 
 	// If there are no missing indices, all data column sidecars are available.
 	// This is the happy path.
-	if len(missingMap) == 0 {
+	if len(missing) == 0 {
 		return nil
 	}
 
@@ -775,33 +769,17 @@ func (s *Service) areDataColumnsAvailable(
 	// Avoid logging if DA check is called after next slot start.
 	if nextSlot.After(time.Now()) {
 		timer := time.AfterFunc(time.Until(nextSlot), func() {
-			missingMapCount := uint64(len(missingMap))
+			missingCount := uint64(len(missing))
 
-			if missingMapCount == 0 {
+			if missingCount == 0 {
 				return
 			}
 
-			var (
-				expected interface{} = "all"
-				missing  interface{} = "all"
-			)
-
-			numberOfColumns := params.BeaconConfig().NumberOfColumns
-			colMapCount := uint64(len(peerInfo.CustodyColumns))
-
-			if colMapCount < numberOfColumns {
-				expected = uint64MapToSortedSlice(peerInfo.CustodyColumns)
-			}
-
-			if missingMapCount < numberOfColumns {
-				missing = uint64MapToSortedSlice(missingMap)
-			}
-
 			log.WithFields(logrus.Fields{
 				"slot":            block.Slot(),
 				"root":            fmt.Sprintf("%#x", root),
-				"columnsExpected": expected,
-				"columnsWaiting":  missing,
+				"columnsExpected": helpers.SortedPrettySliceFromMap(peerInfo.CustodyColumns),
+				"columnsWaiting":  helpers.SortedPrettySliceFromMap(missing),
 			}).Warning("Data columns still missing at slot end")
 		})
 		defer timer.Stop()
@@ -817,7 +795,7 @@ func (s *Service) areDataColumnsAvailable(
 
 			for _, index := range idents.Indices {
 				// This is a data column we are expecting.
-				if _, ok := missingMap[index]; ok {
+				if _, ok := missing[index]; ok {
 					storedDataColumnsCount++
 				}
 
@@ -828,10 +806,10 @@ func (s *Service) areDataColumnsAvailable(
 				}
 
 				// Remove the index from the missing map.
-				delete(missingMap, index)
+				delete(missing, index)
 
 				// Return if there is no more missing data columns.
-				if len(missingMap) == 0 {
+				if len(missing) == 0 {
 					return nil
 				}
 			}
@@ -839,10 +817,10 @@ func (s *Service) areDataColumnsAvailable(
 		case <-ctx.Done():
 			var missingIndices interface{} = "all"
 			numberOfColumns := params.BeaconConfig().NumberOfColumns
-			missingIndicesCount := uint64(len(missingMap))
+			missingIndicesCount := uint64(len(missing))
 
 			if missingIndicesCount < numberOfColumns {
-				missingIndices = uint64MapToSortedSlice(missingMap)
+				missingIndices = helpers.SortedPrettySliceFromMap(missing)
 			}
 
 			return errors.Wrapf(ctx.Err(), "data column sidecars slot: %d, BlockRoot: %#x, missing: %v", block.Slot(), root, missingIndices)
@@ -926,16 +904,6 @@ func (s *Service) areBlobsAvailable(ctx context.Context, root [fieldparams.RootL
 	}
 }
 
-// uint64MapToSortedSlice produces a sorted uint64 slice from a map.
-func uint64MapToSortedSlice(input map[uint64]bool) []uint64 {
-	output := make([]uint64, 0, len(input))
-	for idx := range input {
-		output = append(output, idx)
-	}
-	slices.Sort[[]uint64](output)
-	return output
-}
-
 // lateBlockTasks  is called 4 seconds into the slot and performs tasks
 // related to late blocks. It emits a MissedSlot state feed event.
 // It calls FCU and sets the right attributes if we are proposing next slot

beacon-chain/blockchain/process_block_helpers.go

@@ -3,14 +3,12 @@ package blockchain
 import (
 	"context"
 	"fmt"
-	"strings"
+	"slices"
 	"time"
 
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
-	lightclient "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client"
-
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed"
 	statefeed "github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed/state"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/transition"
 	doublylinkedtree "github.com/OffchainLabs/prysm/v6/beacon-chain/forkchoice/doubly-linked-tree"
 	forkchoicetypes "github.com/OffchainLabs/prysm/v6/beacon-chain/forkchoice/types"
@@ -30,6 +28,10 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
+// ErrInvalidCheckpointArgs may be returned when the finalized checkpoint has an epoch greater than the justified checkpoint epoch.
+// If you are seeing this error, make sure you haven't mixed up the order of the arguments in the method you are calling.
+var ErrInvalidCheckpointArgs = errors.New("finalized checkpoint cannot be greater than justified checkpoint")
+
 // CurrentSlot returns the current slot based on time.
 func (s *Service) CurrentSlot() primitives.Slot {
 	return slots.CurrentSlot(s.genesisTime)
@@ -129,35 +131,26 @@ func (s *Service) sendStateFeedOnBlock(cfg *postBlockProcessConfig) {
 	})
 }
 
+// processLightClientUpdates saves the light client data in lcStore, when feature flag is enabled.
 func (s *Service) processLightClientUpdates(cfg *postBlockProcessConfig) {
-	if err := s.processLightClientUpdate(cfg); err != nil {
-		log.WithError(err).Error("Failed to process light client update")
-	}
-	if err := s.processLightClientOptimisticUpdate(cfg.ctx, cfg.roblock, cfg.postState); err != nil {
-		log.WithError(err).Error("Failed to process light client optimistic update")
-	}
-	if err := s.processLightClientFinalityUpdate(cfg.ctx, cfg.roblock, cfg.postState); err != nil {
-		log.WithError(err).Error("Failed to process light client finality update")
-	}
-}
-
-// processLightClientUpdate saves the light client update for this block
-// if it's better than the already saved one, when feature flag is enabled.
-func (s *Service) processLightClientUpdate(cfg *postBlockProcessConfig) error {
 	attestedRoot := cfg.roblock.Block().ParentRoot()
 	attestedBlock, err := s.getBlock(cfg.ctx, attestedRoot)
 	if err != nil {
-		return errors.Wrapf(err, "could not get attested block for root %#x", attestedRoot)
+		log.WithError(err).Error("processLightClientUpdates: Could not get attested block")
+		return
 	}
 	if attestedBlock == nil || attestedBlock.IsNil() {
-		return errors.New("attested block is nil")
+		log.Error("processLightClientUpdates: Could not get attested block")
+		return
 	}
 	attestedState, err := s.cfg.StateGen.StateByRoot(cfg.ctx, attestedRoot)
 	if err != nil {
-		return errors.Wrapf(err, "could not get attested state for root %#x", attestedRoot)
+		log.WithError(err).Error("processLightClientUpdates: Could not get attested state")
+		return
 	}
 	if attestedState == nil || attestedState.IsNil() {
-		return errors.New("attested state is nil")
+		log.Error("processLightClientUpdates: Could not get attested state")
+		return
 	}
 
 	finalizedRoot := attestedState.FinalizedCheckpoint().Root
@@ -165,98 +158,17 @@ func (s *Service) processLightClientUpdate(cfg *postBlockProcessConfig) error {
 	if err != nil {
 		if errors.Is(err, errBlockNotFoundInCacheOrDB) {
 			log.Debugf("Skipping saving light client update because finalized block is nil for root %#x", finalizedRoot)
-			return nil
+			return
 		}
-		return errors.Wrapf(err, "could not get finalized block for root %#x", finalizedRoot)
+		log.WithError(err).Error("processLightClientUpdates: Could not get finalized block")
+		return
 	}
 
-	update, err := lightclient.NewLightClientUpdateFromBeaconState(cfg.ctx, cfg.postState, cfg.roblock, attestedState, attestedBlock, finalizedBlock)
+	err = s.lcStore.SaveLCData(cfg.ctx, cfg.postState, cfg.roblock, attestedState, attestedBlock, finalizedBlock, s.headRoot())
 	if err != nil {
-		return errors.Wrapf(err, "could not create light client update")
+		log.WithError(err).Error("processLightClientUpdates: Could not save light client data")
 	}
-
-	period := slots.SyncCommitteePeriod(slots.ToEpoch(attestedState.Slot()))
-
-	return s.lcStore.SaveLightClientUpdate(cfg.ctx, period, update)
-}
-
-func (s *Service) processLightClientFinalityUpdate(
-	ctx context.Context,
-	signed interfaces.ReadOnlySignedBeaconBlock,
-	postState state.BeaconState,
-) error {
-	attestedRoot := signed.Block().ParentRoot()
-	attestedBlock, err := s.cfg.BeaconDB.Block(ctx, attestedRoot)
-	if err != nil {
-		return errors.Wrapf(err, "could not get attested block for root %#x", attestedRoot)
-	}
-	attestedState, err := s.cfg.StateGen.StateByRoot(ctx, attestedRoot)
-	if err != nil {
-		return errors.Wrapf(err, "could not get attested state for root %#x", attestedRoot)
-	}
-
-	finalizedCheckpoint := attestedState.FinalizedCheckpoint()
-
-	if finalizedCheckpoint == nil {
-		return nil
-	}
-
-	finalizedRoot := bytesutil.ToBytes32(finalizedCheckpoint.Root)
-	finalizedBlock, err := s.cfg.BeaconDB.Block(ctx, finalizedRoot)
-	if err != nil {
-		if errors.Is(err, errBlockNotFoundInCacheOrDB) {
-			log.Debugf("Skipping processing light client finality update: Finalized block is nil for root %#x", finalizedRoot)
-			return nil
-		}
-		return errors.Wrapf(err, "could not get finalized block for root %#x", finalizedRoot)
-	}
-
-	newUpdate, err := lightclient.NewLightClientFinalityUpdateFromBeaconState(ctx, postState, signed, attestedState, attestedBlock, finalizedBlock)
-
-	if err != nil {
-		return errors.Wrap(err, "could not create light client finality update")
-	}
-
-	if !lightclient.IsBetterFinalityUpdate(newUpdate, s.lcStore.LastFinalityUpdate()) {
-		log.Debug("Skip saving light client finality update: current update is better")
-		return nil
-	}
-
-	s.lcStore.SetLastFinalityUpdate(newUpdate, true)
-
-	return nil
-}
-
-func (s *Service) processLightClientOptimisticUpdate(ctx context.Context, signed interfaces.ReadOnlySignedBeaconBlock,
-	postState state.BeaconState) error {
-	attestedRoot := signed.Block().ParentRoot()
-	attestedBlock, err := s.cfg.BeaconDB.Block(ctx, attestedRoot)
-	if err != nil {
-		return errors.Wrapf(err, "could not get attested block for root %#x", attestedRoot)
-	}
-	attestedState, err := s.cfg.StateGen.StateByRoot(ctx, attestedRoot)
-	if err != nil {
-		return errors.Wrapf(err, "could not get attested state for root %#x", attestedRoot)
-	}
-
-	newUpdate, err := lightclient.NewLightClientOptimisticUpdateFromBeaconState(ctx, postState, signed, attestedState, attestedBlock)
-
-	if err != nil {
-		if strings.Contains(err.Error(), lightclient.ErrNotEnoughSyncCommitteeBits) {
-			log.WithError(err).Debug("Skipping processing light client optimistic update")
-			return nil
-		}
-		return errors.Wrap(err, "could not create light client optimistic update")
-	}
-
-	if !lightclient.IsBetterOptimisticUpdate(newUpdate, s.lcStore.LastOptimisticUpdate()) {
-		log.Debug("Skip saving light client optimistic update: current update is better")
-		return nil
-	}
-
-	s.lcStore.SetLastOptimisticUpdate(newUpdate, true)
-
-	return nil
+	log.Debug("Processed light client updates")
 }
 
 // updateCachesPostBlockProcessing updates the next slot cache and handles the epoch
@@ -454,6 +366,9 @@ func (s *Service) ancestorByDB(ctx context.Context, r [32]byte, slot primitives.
 // This is useful for block tree visualizer and additional vote accounting.
 func (s *Service) fillInForkChoiceMissingBlocks(ctx context.Context, signed interfaces.ReadOnlySignedBeaconBlock,
 	fCheckpoint, jCheckpoint *ethpb.Checkpoint) error {
+	if fCheckpoint.Epoch > jCheckpoint.Epoch {
+		return ErrInvalidCheckpointArgs
+	}
 	pendingNodes := make([]*forkchoicetypes.BlockAndCheckpoints, 0)
 
 	// Fork choice only matters from last finalized slot.
@@ -462,15 +377,8 @@ func (s *Service) fillInForkChoiceMissingBlocks(ctx context.Context, signed inte
 	if err != nil {
 		return err
 	}
-	// The first block can have a bogus root since the block is not inserted in forkchoice
-	roblock, err := consensus_blocks.NewROBlockWithRoot(signed, [32]byte{})
-	if err != nil {
-		return err
-	}
-	pendingNodes = append(pendingNodes, &forkchoicetypes.BlockAndCheckpoints{Block: roblock,
-		JustifiedCheckpoint: jCheckpoint, FinalizedCheckpoint: fCheckpoint})
+	root := signed.Block().ParentRoot()
 	// As long as parent node is not in fork choice store, and parent node is in DB.
-	root := roblock.Block().ParentRoot()
 	for !s.cfg.ForkChoiceStore.HasNode(root) && s.cfg.BeaconDB.HasBlock(ctx, root) {
 		b, err := s.getBlock(ctx, root)
 		if err != nil {
@@ -489,12 +397,13 @@ func (s *Service) fillInForkChoiceMissingBlocks(ctx context.Context, signed inte
 			FinalizedCheckpoint: fCheckpoint}
 		pendingNodes = append(pendingNodes, args)
 	}
-	if len(pendingNodes) == 1 {
+	if len(pendingNodes) == 0 {
 		return nil
 	}
 	if root != s.ensureRootNotZeros(finalized.Root) && !s.cfg.ForkChoiceStore.HasNode(root) {
 		return ErrNotDescendantOfFinalized
 	}
+	slices.Reverse(pendingNodes)
 	return s.cfg.ForkChoiceStore.InsertChain(ctx, pendingNodes)
 }
 

beacon-chain/blockchain/process_block_test.go

@@ -12,7 +12,6 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/cache"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/blocks"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
-	lightClient "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/signing"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/transition"
@@ -24,6 +23,7 @@ import (
 	mockExecution "github.com/OffchainLabs/prysm/v6/beacon-chain/execution/testing"
 	doublylinkedtree "github.com/OffchainLabs/prysm/v6/beacon-chain/forkchoice/doubly-linked-tree"
 	forkchoicetypes "github.com/OffchainLabs/prysm/v6/beacon-chain/forkchoice/types"
+	lightClient "github.com/OffchainLabs/prysm/v6/beacon-chain/light-client"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/operations/attestations/kv"
 	mockp2p "github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/testing"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
@@ -375,6 +375,81 @@ func TestFillForkChoiceMissingBlocks_FinalizedSibling(t *testing.T) {
 	require.Equal(t, ErrNotDescendantOfFinalized.Error(), err.Error())
 }
 
+func TestFillForkChoiceMissingBlocks_ErrorCases(t *testing.T) {
+	tests := []struct {
+		name           string
+		finalizedEpoch primitives.Epoch
+		justifiedEpoch primitives.Epoch
+		expectedError  error
+	}{
+		{
+			name:           "finalized epoch greater than justified epoch",
+			finalizedEpoch: 5,
+			justifiedEpoch: 3,
+			expectedError:  ErrInvalidCheckpointArgs,
+		},
+		{
+			name:           "valid case - finalized equal to justified",
+			finalizedEpoch: 3,
+			justifiedEpoch: 3,
+			expectedError:  nil,
+		},
+		{
+			name:           "valid case - finalized less than justified",
+			finalizedEpoch: 2,
+			justifiedEpoch: 3,
+			expectedError:  nil,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			service, tr := minimalTestService(t)
+			ctx, beaconDB := tr.ctx, tr.db
+
+			st, _ := util.DeterministicGenesisState(t, 64)
+			require.NoError(t, service.saveGenesisData(ctx, st))
+
+			// Create a simple block for testing
+			blk := util.NewBeaconBlock()
+			blk.Block.Slot = 10
+			blk.Block.ParentRoot = service.originBlockRoot[:]
+			wsb, err := consensusblocks.NewSignedBeaconBlock(blk)
+			require.NoError(t, err)
+			util.SaveBlock(t, ctx, beaconDB, blk)
+
+			// Create checkpoints with test case epochs
+			finalizedCheckpoint := &ethpb.Checkpoint{
+				Epoch: tt.finalizedEpoch,
+				Root:  service.originBlockRoot[:],
+			}
+			justifiedCheckpoint := &ethpb.Checkpoint{
+				Epoch: tt.justifiedEpoch,
+				Root:  service.originBlockRoot[:],
+			}
+
+			// Set up forkchoice store to avoid other errors
+			fcp := &ethpb.Checkpoint{Epoch: 0, Root: service.originBlockRoot[:]}
+			state, blkRoot, err := prepareForkchoiceState(ctx, 0, service.originBlockRoot, service.originBlockRoot, [32]byte{}, fcp, fcp)
+			require.NoError(t, err)
+			require.NoError(t, service.cfg.ForkChoiceStore.InsertNode(ctx, state, blkRoot))
+
+			err = service.fillInForkChoiceMissingBlocks(
+				t.Context(), wsb, finalizedCheckpoint, justifiedCheckpoint)
+
+			if tt.expectedError != nil {
+				require.ErrorIs(t, err, tt.expectedError)
+			} else {
+				// For valid cases, we might get other errors (like block not being descendant of finalized)
+				// but we shouldn't get the checkpoint validation error
+				if err != nil && errors.Is(err, tt.expectedError) {
+					t.Errorf("Unexpected checkpoint validation error: %v", err)
+				}
+			}
+		})
+	}
+}
+
 // blockTree1 constructs the following tree:
 //
 //	/- B1
@@ -2132,13 +2207,13 @@ func TestNoViableHead_Reboot(t *testing.T) {
 
 	// Forkchoice has the genesisRoot loaded at startup
 	require.Equal(t, genesisRoot, service.ensureRootNotZeros(service.cfg.ForkChoiceStore.CachedHeadRoot()))
-	// Service's store has the finalized state as headRoot
+	// Service's store has the justified checkpoint root as headRoot (verified below through justified checkpoint comparison)
 	headRoot, err := service.HeadRoot(ctx)
 	require.NoError(t, err)
-	require.Equal(t, genesisRoot, bytesutil.ToBytes32(headRoot))
+	require.NotEqual(t, bytesutil.ToBytes32(params.BeaconConfig().ZeroHash[:]), bytesutil.ToBytes32(headRoot)) // Ensure head is not zero
 	optimistic, err := service.IsOptimistic(ctx)
 	require.NoError(t, err)
-	require.Equal(t, false, optimistic)
+	require.Equal(t, true, optimistic) // Head is now optimistic when starting from justified checkpoint
 
 	// Check that the node's justified checkpoint does not agree with the
 	// last valid state's justified checkpoint
@@ -2720,6 +2795,11 @@ func TestProcessLightClientUpdate(t *testing.T) {
 	s, tr := minimalTestService(t, WithLCStore())
 	ctx := tr.ctx
 
+	headState, err := util.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, s.cfg.BeaconDB.SaveState(ctx, headState, [32]byte{1, 2}))
+	require.NoError(t, s.cfg.BeaconDB.SaveHeadBlockRoot(ctx, [32]byte{1, 2}))
+
 	for testVersion := version.Altair; testVersion <= version.Electra; testVersion++ {
 		t.Run(version.String(testVersion), func(t *testing.T) {
 			l := util.NewTestLightClient(t, testVersion)
@@ -2742,6 +2822,8 @@ func TestProcessLightClientUpdate(t *testing.T) {
 			require.NoError(t, err)
 			err = s.cfg.BeaconDB.SaveState(ctx, l.State, currentBlockRoot)
 			require.NoError(t, err)
+			err = s.cfg.BeaconDB.SaveHeadBlockRoot(ctx, currentBlockRoot)
+			require.NoError(t, err)
 
 			err = s.cfg.BeaconDB.SaveBlock(ctx, l.FinalizedBlock)
 			require.NoError(t, err)
@@ -2756,10 +2838,9 @@ func TestProcessLightClientUpdate(t *testing.T) {
 			period := slots.SyncCommitteePeriod(slots.ToEpoch(l.AttestedState.Slot()))
 
 			t.Run("no old update", func(t *testing.T) {
-				require.NoError(t, s.processLightClientUpdate(cfg))
-
+				s.processLightClientUpdates(cfg)
 				// Check that the light client update is saved
-				u, err := s.lcStore.LightClientUpdate(ctx, period)
+				u, err := s.lcStore.LightClientUpdate(ctx, period, l.Block)
 				require.NoError(t, err)
 				require.NotNil(t, u)
 				attestedStateRoot, err := l.AttestedState.HashTreeRoot(ctx)
@@ -2773,12 +2854,12 @@ func TestProcessLightClientUpdate(t *testing.T) {
 				oldUpdate, err := lightClient.CreateDefaultLightClientUpdate(l.AttestedBlock)
 				require.NoError(t, err)
 
-				err = s.lcStore.SaveLightClientUpdate(ctx, period, oldUpdate)
+				err = s.cfg.BeaconDB.SaveLightClientUpdate(ctx, period, oldUpdate)
 				require.NoError(t, err)
 
-				require.NoError(t, s.processLightClientUpdate(cfg))
+				s.processLightClientUpdates(cfg)
 
-				u, err := s.lcStore.LightClientUpdate(ctx, period)
+				u, err := s.lcStore.LightClientUpdate(ctx, period, l.Block)
 				require.NoError(t, err)
 				require.NotNil(t, u)
 				attestedStateRoot, err := l.AttestedState.HashTreeRoot(ctx)
@@ -2802,12 +2883,12 @@ func TestProcessLightClientUpdate(t *testing.T) {
 					SyncCommitteeSignature: make([]byte, 96),
 				})
 
-				err = s.lcStore.SaveLightClientUpdate(ctx, period, oldUpdate)
+				err = s.cfg.BeaconDB.SaveLightClientUpdate(ctx, period, oldUpdate)
 				require.NoError(t, err)
 
-				require.NoError(t, s.processLightClientUpdate(cfg))
+				s.processLightClientUpdates(cfg)
 
-				u, err := s.lcStore.LightClientUpdate(ctx, period)
+				u, err := s.lcStore.LightClientUpdate(ctx, period, l.Block)
 				require.NoError(t, err)
 				require.NotNil(t, u)
 				require.DeepEqual(t, oldUpdate, u)
@@ -2877,14 +2958,18 @@ func TestIsDataAvailable(t *testing.T) {
 		params := testIsAvailableParams{options: []Option{WithGenesisTime(time.Unix(0, 0))}}
 		ctx, _, service, root, signed := testIsAvailableSetup(t, params)
 
-		err := service.isDataAvailable(ctx, root, signed)
+		roBlock, err := consensusblocks.NewROBlockWithRoot(signed, root)
+		require.NoError(t, err)
+		err = service.isDataAvailable(ctx, roBlock)
 		require.NoError(t, err)
 	})
 
 	t.Run("Fulu - no commitment in blocks", func(t *testing.T) {
 		ctx, _, service, root, signed := testIsAvailableSetup(t, testIsAvailableParams{})
 
-		err := service.isDataAvailable(ctx, root, signed)
+		roBlock, err := consensusblocks.NewROBlockWithRoot(signed, root)
+		require.NoError(t, err)
+		err = service.isDataAvailable(ctx, roBlock)
 		require.NoError(t, err)
 	})
 
@@ -2902,7 +2987,9 @@ func TestIsDataAvailable(t *testing.T) {
 
 		ctx, _, service, root, signed := testIsAvailableSetup(t, params)
 
-		err := service.isDataAvailable(ctx, root, signed)
+		roBlock, err := consensusblocks.NewROBlockWithRoot(signed, root)
+		require.NoError(t, err)
+		err = service.isDataAvailable(ctx, roBlock)
 		require.NoError(t, err)
 	})
 
@@ -2914,7 +3001,9 @@ func TestIsDataAvailable(t *testing.T) {
 
 		ctx, _, service, root, signed := testIsAvailableSetup(t, params)
 
-		err := service.isDataAvailable(ctx, root, signed)
+		roBlock, err := consensusblocks.NewROBlockWithRoot(signed, root)
+		require.NoError(t, err)
+		err = service.isDataAvailable(ctx, roBlock)
 		require.NoError(t, err)
 	})
 
@@ -2962,7 +3051,9 @@ func TestIsDataAvailable(t *testing.T) {
 		ctx, cancel := context.WithTimeout(ctx, time.Second*2)
 		defer cancel()
 
-		err = service.isDataAvailable(ctx, root, signed)
+		roBlock, err := consensusblocks.NewROBlockWithRoot(signed, root)
+		require.NoError(t, err)
+		err = service.isDataAvailable(ctx, roBlock)
 		require.NoError(t, err)
 	})
 
@@ -3024,7 +3115,9 @@ func TestIsDataAvailable(t *testing.T) {
 		ctx, cancel := context.WithTimeout(ctx, time.Second*2)
 		defer cancel()
 
-		err = service.isDataAvailable(ctx, root, signed)
+		roBlock, err := consensusblocks.NewROBlockWithRoot(signed, root)
+		require.NoError(t, err)
+		err = service.isDataAvailable(ctx, roBlock)
 		require.NoError(t, err)
 	})
 
@@ -3043,7 +3136,9 @@ func TestIsDataAvailable(t *testing.T) {
 			cancel()
 		}()
 
-		err := service.isDataAvailable(ctx, root, signed)
+		roBlock, err := consensusblocks.NewROBlockWithRoot(signed, root)
+		require.NoError(t, err)
+		err = service.isDataAvailable(ctx, roBlock)
 		require.NotNil(t, err)
 	})
 }
@@ -3115,6 +3210,11 @@ func TestProcessLightClientOptimisticUpdate(t *testing.T) {
 	s.cfg.P2P = &mockp2p.FakeP2P{}
 	ctx := tr.ctx
 
+	headState, err := util.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, s.cfg.BeaconDB.SaveState(ctx, headState, [32]byte{1, 2}))
+	require.NoError(t, s.cfg.BeaconDB.SaveHeadBlockRoot(ctx, [32]byte{1, 2}))
+
 	testCases := []struct {
 		name          string
 		oldOptions    []util.LightClientOption
@@ -3130,7 +3230,7 @@ func TestProcessLightClientOptimisticUpdate(t *testing.T) {
 		{
 			name:          "Same age",
 			oldOptions:    []util.LightClientOption{},
-			newOptions:    []util.LightClientOption{util.WithSupermajority()}, // supermajority does not matter here and is only added to result in two different updates
+			newOptions:    []util.LightClientOption{util.WithSupermajority(0)}, // supermajority does not matter here and is only added to result in two different updates
 			expectReplace: false,
 		},
 		{
@@ -3174,14 +3274,14 @@ func TestProcessLightClientOptimisticUpdate(t *testing.T) {
 
 			t.Run(version.String(testVersion)+"_"+tc.name, func(t *testing.T) {
 				s.genesisTime = time.Unix(time.Now().Unix()-(int64(forkEpoch)*int64(params.BeaconConfig().SlotsPerEpoch)*int64(params.BeaconConfig().SecondsPerSlot)), 0)
-				s.lcStore = lightClient.NewLightClientStore(s.cfg.BeaconDB, s.cfg.P2P, s.cfg.StateNotifier.StateFeed())
+				s.lcStore = lightClient.NewLightClientStore(s.cfg.P2P, s.cfg.StateNotifier.StateFeed(), s.cfg.BeaconDB)
 
 				var oldActualUpdate interfaces.LightClientOptimisticUpdate
 				var err error
 				if tc.oldOptions != nil {
 					// config for old update
 					lOld, cfgOld := setupLightClientTestRequirements(ctx, t, s, testVersion, tc.oldOptions...)
-					require.NoError(t, s.processLightClientOptimisticUpdate(cfgOld.ctx, cfgOld.roblock, cfgOld.postState))
+					s.processLightClientUpdates(cfgOld)
 
 					oldActualUpdate, err = lightClient.NewLightClientOptimisticUpdateFromBeaconState(lOld.Ctx, lOld.State, lOld.Block, lOld.AttestedState, lOld.AttestedBlock)
 					require.NoError(t, err)
@@ -3195,7 +3295,7 @@ func TestProcessLightClientOptimisticUpdate(t *testing.T) {
 
 				// config for new update
 				lNew, cfgNew := setupLightClientTestRequirements(ctx, t, s, testVersion, tc.newOptions...)
-				require.NoError(t, s.processLightClientOptimisticUpdate(cfgNew.ctx, cfgNew.roblock, cfgNew.postState))
+				s.processLightClientUpdates(cfgNew)
 
 				newActualUpdate, err := lightClient.NewLightClientOptimisticUpdateFromBeaconState(lNew.Ctx, lNew.State, lNew.Block, lNew.AttestedState, lNew.AttestedBlock)
 				require.NoError(t, err)
@@ -3236,6 +3336,7 @@ func TestProcessLightClientFinalityUpdate(t *testing.T) {
 	s, tr := minimalTestService(t)
 	s.cfg.P2P = &mockp2p.FakeP2P{}
 	ctx := tr.ctx
+	s.head = &head{}
 
 	testCases := []struct {
 		name          string
@@ -3314,15 +3415,18 @@ func TestProcessLightClientFinalityUpdate(t *testing.T) {
 
 			t.Run(version.String(testVersion)+"_"+tc.name, func(t *testing.T) {
 				s.genesisTime = time.Unix(time.Now().Unix()-(int64(forkEpoch)*int64(params.BeaconConfig().SlotsPerEpoch)*int64(params.BeaconConfig().SecondsPerSlot)), 0)
-				s.lcStore = lightClient.NewLightClientStore(s.cfg.BeaconDB, s.cfg.P2P, s.cfg.StateNotifier.StateFeed())
+				s.lcStore = lightClient.NewLightClientStore(s.cfg.P2P, s.cfg.StateNotifier.StateFeed(), s.cfg.BeaconDB)
 
 				var actualOldUpdate, actualNewUpdate interfaces.LightClientFinalityUpdate
-				var err error
 
 				if tc.oldOptions != nil {
 					// config for old update
 					lOld, cfgOld := setupLightClientTestRequirements(ctx, t, s, testVersion, tc.oldOptions...)
-					require.NoError(t, s.processLightClientFinalityUpdate(cfgOld.ctx, cfgOld.roblock, cfgOld.postState))
+					blkRoot, err := lOld.Block.Block().HashTreeRoot()
+					require.NoError(t, err)
+					s.head.block = lOld.Block
+					s.head.root = blkRoot
+					s.processLightClientUpdates(cfgOld)
 
 					// check that the old update is saved
 					actualOldUpdate, err = lightClient.NewLightClientFinalityUpdateFromBeaconState(ctx, cfgOld.postState, cfgOld.roblock, lOld.AttestedState, lOld.AttestedBlock, lOld.FinalizedBlock)
@@ -3333,7 +3437,11 @@ func TestProcessLightClientFinalityUpdate(t *testing.T) {
 
 				// config for new update
 				lNew, cfgNew := setupLightClientTestRequirements(ctx, t, s, testVersion, tc.newOptions...)
-				require.NoError(t, s.processLightClientFinalityUpdate(cfgNew.ctx, cfgNew.roblock, cfgNew.postState))
+				blkRoot, err := lNew.Block.Block().HashTreeRoot()
+				require.NoError(t, err)
+				s.head.block = lNew.Block
+				s.head.root = blkRoot
+				s.processLightClientUpdates(cfgNew)
 
 				// check that the actual old update and the actual new update are different
 				actualNewUpdate, err = lightClient.NewLightClientFinalityUpdateFromBeaconState(ctx, cfgNew.postState, cfgNew.roblock, lNew.AttestedState, lNew.AttestedBlock, lNew.FinalizedBlock)

beacon-chain/blockchain/receive_block.go

@@ -16,7 +16,6 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/slasher/types"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
 	"github.com/OffchainLabs/prysm/v6/config/features"
-	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
@@ -93,7 +92,7 @@ func (s *Service) ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySig
 
 	blockCopy, err := block.Copy()
 	if err != nil {
-		return err
+		return errors.Wrap(err, "block copy")
 	}
 
 	preState, err := s.getBlockPreState(ctx, blockCopy.Block())
@@ -104,17 +103,17 @@ func (s *Service) ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySig
 	currentCheckpoints := s.saveCurrentCheckpoints(preState)
 	roblock, err := blocks.NewROBlockWithRoot(blockCopy, blockRoot)
 	if err != nil {
-		return err
+		return errors.Wrap(err, "new ro block with root")
 	}
 
 	postState, isValidPayload, err := s.validateExecutionAndConsensus(ctx, preState, roblock)
 	if err != nil {
-		return err
+		return errors.Wrap(err, "validator execution and consensus")
 	}
 
-	daWaitedTime, err := s.handleDA(ctx, blockCopy, blockRoot, avs)
+	daWaitedTime, err := s.handleDA(ctx, avs, roblock)
 	if err != nil {
-		return err
+		return errors.Wrap(err, "handle da")
 	}
 
 	// Defragment the state before continuing block processing.
@@ -135,10 +134,10 @@ func (s *Service) ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySig
 	if err := s.postBlockProcess(args); err != nil {
 		err := errors.Wrap(err, "could not process block")
 		tracing.AnnotateError(span, err)
-		return err
+		return errors.Wrap(err, "post block process")
 	}
 	if err := s.updateCheckpoints(ctx, currentCheckpoints, preState, postState, blockRoot); err != nil {
-		return err
+		return errors.Wrap(err, "update checkpoints")
 	}
 	// If slasher is configured, forward the attestations in the block via an event feed for processing.
 	if s.slasherEnabled {
@@ -152,12 +151,12 @@ func (s *Service) ReceiveBlock(ctx context.Context, block interfaces.ReadOnlySig
 
 	// Have we been finalizing? Should we start saving hot states to db?
 	if err := s.checkSaveHotStateDB(ctx); err != nil {
-		return err
+		return errors.Wrap(err, "check save hot state db")
 	}
 
 	// We apply the same heuristic to some of our more important caches.
 	if err := s.handleCaches(); err != nil {
-		return err
+		return errors.Wrap(err, "handle caches")
 	}
 	s.reportPostBlockProcessing(blockCopy, blockRoot, receivedTime, daWaitedTime)
 	return nil
@@ -240,37 +239,19 @@ func (s *Service) validateExecutionAndConsensus(
 	return postState, isValidPayload, nil
 }
 
-func (s *Service) handleDA(
-	ctx context.Context,
-	block interfaces.SignedBeaconBlock,
-	blockRoot [fieldparams.RootLength]byte,
-	avs das.AvailabilityStore,
-) (elapsed time.Duration, err error) {
-	defer func(start time.Time) {
-		elapsed = time.Since(start)
-
-		if err == nil {
-			dataAvailWaitedTime.Observe(float64(elapsed.Milliseconds()))
-		}
-	}(time.Now())
-
-	if avs == nil {
-		if err = s.isDataAvailable(ctx, blockRoot, block); err != nil {
-			return
-		}
-
-		return
+func (s *Service) handleDA(ctx context.Context, avs das.AvailabilityStore, block blocks.ROBlock) (time.Duration, error) {
+	var err error
+	start := time.Now()
+	if avs != nil {
+		err = avs.IsDataAvailable(ctx, s.CurrentSlot(), block)
+	} else {
+		err = s.isDataAvailable(ctx, block)
 	}
-
-	var rob blocks.ROBlock
-	rob, err = blocks.NewROBlockWithRoot(block, blockRoot)
-	if err != nil {
-		return
+	elapsed := time.Since(start)
+	if err == nil {
+		dataAvailWaitedTime.Observe(float64(elapsed.Milliseconds()))
 	}
-
-	err = avs.IsDataAvailable(ctx, s.CurrentSlot(), rob)
-
-	return
+	return elapsed, err
 }
 
 func (s *Service) reportPostBlockProcessing(
@@ -320,13 +301,28 @@ func (s *Service) executePostFinalizationTasks(ctx context.Context, finalizedSta
 	if features.Get().EnableLightClient {
 		// Save a light client bootstrap for the finalized checkpoint
 		go func() {
-			err := s.lcStore.SaveLightClientBootstrap(s.ctx, finalized.Root)
+			st, err := s.cfg.StateGen.StateByRoot(ctx, finalized.Root)
+			if err != nil {
+				log.WithError(err).Error("Could not retrieve state for finalized root to save light client bootstrap")
+				return
+			}
+			err = s.lcStore.SaveLightClientBootstrap(s.ctx, finalized.Root, st)
 			if err != nil {
 				log.WithError(err).Error("Could not save light client bootstrap by block root")
 			} else {
 				log.Debugf("Saved light client bootstrap for finalized root %#x", finalized.Root)
 			}
 		}()
+
+		// Clean up the light client store caches
+		go func() {
+			err := s.lcStore.MigrateToCold(s.ctx, finalized.Root)
+			if err != nil {
+				log.WithError(err).Error("Could not migrate light client store to cold storage")
+			} else {
+				log.Debugf("Migrated light client store to cold storage for finalized root %#x", finalized.Root)
+			}
+		}()
 	}
 }
 

beacon-chain/blockchain/receive_block_test.go

@@ -9,9 +9,9 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/cache"
 	statefeed "github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed/state"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
-	lightClient "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/das"
 	forkchoicetypes "github.com/OffchainLabs/prysm/v6/beacon-chain/forkchoice/types"
+	lightClient "github.com/OffchainLabs/prysm/v6/beacon-chain/light-client"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/operations/voluntaryexits"
 	"github.com/OffchainLabs/prysm/v6/config/features"
 	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
@@ -192,7 +192,9 @@ func TestHandleDA(t *testing.T) {
 	require.NoError(t, err)
 
 	s, _ := minimalTestService(t)
-	elapsed, err := s.handleDA(t.Context(), signedBeaconBlock, [fieldparams.RootLength]byte{}, nil)
+	block, err := blocks.NewROBlockWithRoot(signedBeaconBlock, [32]byte{})
+	require.NoError(t, err)
+	elapsed, err := s.handleDA(t.Context(), nil, block)
 	require.NoError(t, err)
 	require.Equal(t, true, elapsed > 0, "Elapsed time should be greater than 0")
 }
@@ -594,11 +596,7 @@ func TestProcessLightClientBootstrap(t *testing.T) {
 
 			require.NoError(t, s.cfg.ForkChoiceStore.UpdateFinalizedCheckpoint(&forkchoicetypes.Checkpoint{Epoch: cp.Epoch, Root: [32]byte(cp.Root)}))
 
-			sss, err := s.cfg.BeaconDB.State(ctx, finalizedBlockRoot)
-			require.NoError(t, err)
-			require.NotNil(t, sss)
-
-			s.executePostFinalizationTasks(s.ctx, l.FinalizedState)
+			s.executePostFinalizationTasks(s.ctx, l.AttestedState)
 
 			// wait for the goroutine to finish processing
 			time.Sleep(1 * time.Second)

beacon-chain/blockchain/service.go

@@ -14,13 +14,13 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/cache"
 	statefeed "github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed/state"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
-	lightClient "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client"
 	coreTime "github.com/OffchainLabs/prysm/v6/beacon-chain/core/time"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/transition"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filesystem"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/execution"
 	f "github.com/OffchainLabs/prysm/v6/beacon-chain/forkchoice"
+	lightClient "github.com/OffchainLabs/prysm/v6/beacon-chain/light-client"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/operations/attestations"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/operations/blstoexec"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/operations/slashings"

beacon-chain/blockchain/setup_forkchoice.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
+	"slices"
 
 	forkchoicetypes "github.com/OffchainLabs/prysm/v6/beacon-chain/forkchoice/types"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
@@ -20,7 +21,7 @@ func (s *Service) setupForkchoice(st state.BeaconState) error {
 		return errors.Wrap(err, "could not set up forkchoice checkpoints")
 	}
 	if err := s.setupForkchoiceTree(st); err != nil {
-		return errors.Wrap(err, "could not set up forkchoice root")
+		return errors.Wrap(err, "could not set up forkchoice tree")
 	}
 	if err := s.initializeHead(s.ctx, st); err != nil {
 		return errors.Wrap(err, "could not initialize head from db")
@@ -30,24 +31,24 @@ func (s *Service) setupForkchoice(st state.BeaconState) error {
 
 func (s *Service) startupHeadRoot() [32]byte {
 	headStr := features.Get().ForceHead
-	cp := s.FinalizedCheckpt()
-	fRoot := s.ensureRootNotZeros([32]byte(cp.Root))
+	jp := s.CurrentJustifiedCheckpt()
+	jRoot := s.ensureRootNotZeros([32]byte(jp.Root))
 	if headStr == "" {
-		return fRoot
+		return jRoot
 	}
 	if headStr == "head" {
 		root, err := s.cfg.BeaconDB.HeadBlockRoot()
 		if err != nil {
-			log.WithError(err).Error("Could not get head block root, starting with finalized block as head")
-			return fRoot
+			log.WithError(err).Error("Could not get head block root, starting with justified block as head")
+			return jRoot
 		}
 		log.Infof("Using Head root of %#x", root)
 		return root
 	}
 	root, err := bytesutil.DecodeHexWithLength(headStr, 32)
 	if err != nil {
-		log.WithError(err).Error("Could not parse head root, starting with finalized block as head")
-		return fRoot
+		log.WithError(err).Error("Could not parse head root, starting with justified block as head")
+		return jRoot
 	}
 	return [32]byte(root)
 }
@@ -112,6 +113,7 @@ func (s *Service) buildForkchoiceChain(ctx context.Context, head interfaces.Read
 			return nil, errors.New("head block is not a descendant of the finalized checkpoint")
 		}
 	}
+	slices.Reverse(chain)
 	return chain, nil
 }
 

beacon-chain/blockchain/setup_forkchoice_test.go

@@ -32,7 +32,7 @@ func Test_startupHeadRoot(t *testing.T) {
 		})
 		defer resetCfg()
 		require.Equal(t, service.startupHeadRoot(), gr)
-		require.LogsContain(t, hook, "Could not get head block root, starting with finalized block as head")
+		require.LogsContain(t, hook, "Could not get head block root, starting with justified block as head")
 	})
 
 	st, _ := util.DeterministicGenesisState(t, 64)
@@ -124,5 +124,5 @@ func Test_setupForkchoiceTree_Head(t *testing.T) {
 	require.NotEqual(t, fRoot, root)
 	require.Equal(t, root, service.startupHeadRoot())
 	require.NoError(t, service.setupForkchoiceTree(st))
-	require.Equal(t, 2, service.cfg.ForkChoiceStore.NodeCount())
+	require.Equal(t, 3, service.cfg.ForkChoiceStore.NodeCount())
 }

beacon-chain/blockchain/setup_test.go

@@ -11,21 +11,21 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/cache"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/cache/depositsnapshot"
 	statefeed "github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed/state"
-	lightclient "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filesystem"
 	testDB "github.com/OffchainLabs/prysm/v6/beacon-chain/db/testing"
 	mockExecution "github.com/OffchainLabs/prysm/v6/beacon-chain/execution/testing"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/forkchoice"
 	doublylinkedtree "github.com/OffchainLabs/prysm/v6/beacon-chain/forkchoice/doubly-linked-tree"
+	lightclient "github.com/OffchainLabs/prysm/v6/beacon-chain/light-client"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/operations/attestations"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/operations/blstoexec"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p"
 	p2pTesting "github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/testing"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/startup"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state/stategen"
-	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v6/config/params"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
@@ -89,7 +89,7 @@ func (mb *mockBroadcaster) BroadcastLightClientFinalityUpdate(_ context.Context,
 	return nil
 }
 
-func (mb *mockBroadcaster) BroadcastDataColumnSidecar(_ [fieldparams.RootLength]byte, _ uint64, _ *ethpb.DataColumnSidecar) error {
+func (mb *mockBroadcaster) BroadcastDataColumnSidecar(_ uint64, _ blocks.VerifiedRODataColumn) error {
 	mb.broadcastCalled = true
 	return nil
 }

beacon-chain/blockchain/testing/mock.go

@@ -723,7 +723,8 @@ func (c *ChainService) ReceiveDataColumn(dc blocks.VerifiedRODataColumn) error {
 }
 
 // ReceiveDataColumns implements the same method in chain service
-func (*ChainService) ReceiveDataColumns(_ []blocks.VerifiedRODataColumn) error {
+func (c *ChainService) ReceiveDataColumns(dcs []blocks.VerifiedRODataColumn) error {
+	c.DataColumns = append(c.DataColumns, dcs...)
 	return nil
 }
 

beacon-chain/cache/sync_committee.go

@@ -67,6 +67,30 @@ func (s *SyncCommitteeCache) Clear() {
 	s.cache = cache.NewFIFO(keyFn)
 }
 
+// CurrentPeriodPositions returns current period positions of validator indices with respect with
+// sync committee. If any input validator index has no assignment, an empty list will be returned
+// for that validator. If the input root does not exist in cache, `ErrNonExistingSyncCommitteeKey` is returned.
+// Manual checking of state for index position in state is recommended when `ErrNonExistingSyncCommitteeKey` is returned.
+func (s *SyncCommitteeCache) CurrentPeriodPositions(root [32]byte, indices []primitives.ValidatorIndex) ([][]primitives.CommitteeIndex, error) {
+	s.lock.RLock()
+	defer s.lock.RUnlock()
+
+	pos, err := s.positionsInCommittee(root, indices)
+	if err != nil {
+		return nil, err
+	}
+	result := make([][]primitives.CommitteeIndex, len(pos))
+	for i, p := range pos {
+		if p == nil {
+			result[i] = []primitives.CommitteeIndex{}
+		} else {
+			result[i] = p.currentPeriod
+		}
+	}
+
+	return result, nil
+}
+
 // CurrentPeriodIndexPosition returns current period index position of a validator index with respect with
 // sync committee. If the input validator index has no assignment, an empty list will be returned.
 // If the input root does not exist in cache, `ErrNonExistingSyncCommitteeKey` is returned.
@@ -104,11 +128,7 @@ func (s *SyncCommitteeCache) NextPeriodIndexPosition(root [32]byte, valIdx primi
 	return pos.nextPeriod, nil
 }
 
-// Helper function for `CurrentPeriodIndexPosition` and `NextPeriodIndexPosition` to return a mapping
-// of validator index to its index(s) position in the sync committee.
-func (s *SyncCommitteeCache) idxPositionInCommittee(
-	root [32]byte, valIdx primitives.ValidatorIndex,
-) (*positionInCommittee, error) {
+func (s *SyncCommitteeCache) positionsInCommittee(root [32]byte, indices []primitives.ValidatorIndex) ([]*positionInCommittee, error) {
 	obj, exists, err := s.cache.GetByKey(key(root))
 	if err != nil {
 		return nil, err
@@ -121,13 +141,33 @@ func (s *SyncCommitteeCache) idxPositionInCommittee(
 	if !ok {
 		return nil, errNotSyncCommitteeIndexPosition
 	}
-	idxInCommittee, ok := item.vIndexToPositionMap[valIdx]
-	if !ok {
-		SyncCommitteeCacheMiss.Inc()
+	result := make([]*positionInCommittee, len(indices))
+	for i, idx := range indices {
+		idxInCommittee, ok := item.vIndexToPositionMap[idx]
+		if ok {
+			SyncCommitteeCacheHit.Inc()
+			result[i] = idxInCommittee
+		} else {
+			SyncCommitteeCacheMiss.Inc()
+			result[i] = nil
+		}
+	}
+	return result, nil
+}
+
+// Helper function for `CurrentPeriodIndexPosition` and `NextPeriodIndexPosition` to return a mapping
+// of validator index to its index(s) position in the sync committee.
+func (s *SyncCommitteeCache) idxPositionInCommittee(
+	root [32]byte, valIdx primitives.ValidatorIndex,
+) (*positionInCommittee, error) {
+	positions, err := s.positionsInCommittee(root, []primitives.ValidatorIndex{valIdx})
+	if err != nil {
+		return nil, err
+	}
+	if len(positions) == 0 {
 		return nil, nil
 	}
-	SyncCommitteeCacheHit.Inc()
-	return idxInCommittee, nil
+	return positions[0], nil
 }
 
 // UpdatePositionsInCommittee updates caching of validators position in sync committee in respect to

beacon-chain/cache/sync_committee_disabled.go

@@ -16,6 +16,11 @@ func NewSyncCommittee() *FakeSyncCommitteeCache {
 	return &FakeSyncCommitteeCache{}
 }
 
+// CurrentPeriodPositions -- fake
+func (s *FakeSyncCommitteeCache) CurrentPeriodPositions(root [32]byte, indices []primitives.ValidatorIndex) ([][]primitives.CommitteeIndex, error) {
+	return nil, nil
+}
+
 // CurrentEpochIndexPosition -- fake.
 func (s *FakeSyncCommitteeCache) CurrentPeriodIndexPosition(root [32]byte, valIdx primitives.ValidatorIndex) ([]primitives.CommitteeIndex, error) {
 	return nil, nil

beacon-chain/core/altair/upgrade.go

@@ -12,6 +12,46 @@ import (
 	"github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1/attestation"
 )
 
+// ConvertToAltair converts a Phase 0 beacon state to an Altair beacon state.
+func ConvertToAltair(state state.BeaconState) (state.BeaconState, error) {
+	epoch := time.CurrentEpoch(state)
+
+	numValidators := state.NumValidators()
+	s := &ethpb.BeaconStateAltair{
+		GenesisTime:           uint64(state.GenesisTime().Unix()),
+		GenesisValidatorsRoot: state.GenesisValidatorsRoot(),
+		Slot:                  state.Slot(),
+		Fork: &ethpb.Fork{
+			PreviousVersion: state.Fork().CurrentVersion,
+			CurrentVersion:  params.BeaconConfig().AltairForkVersion,
+			Epoch:           epoch,
+		},
+		LatestBlockHeader:           state.LatestBlockHeader(),
+		BlockRoots:                  state.BlockRoots(),
+		StateRoots:                  state.StateRoots(),
+		HistoricalRoots:             state.HistoricalRoots(),
+		Eth1Data:                    state.Eth1Data(),
+		Eth1DataVotes:               state.Eth1DataVotes(),
+		Eth1DepositIndex:            state.Eth1DepositIndex(),
+		Validators:                  state.Validators(),
+		Balances:                    state.Balances(),
+		RandaoMixes:                 state.RandaoMixes(),
+		Slashings:                   state.Slashings(),
+		PreviousEpochParticipation:  make([]byte, numValidators),
+		CurrentEpochParticipation:   make([]byte, numValidators),
+		JustificationBits:           state.JustificationBits(),
+		PreviousJustifiedCheckpoint: state.PreviousJustifiedCheckpoint(),
+		CurrentJustifiedCheckpoint:  state.CurrentJustifiedCheckpoint(),
+		FinalizedCheckpoint:         state.FinalizedCheckpoint(),
+		InactivityScores:            make([]uint64, numValidators),
+	}
+	newState, err := state_native.InitializeFromProtoUnsafeAltair(s)
+	if err != nil {
+		return nil, err
+	}
+	return newState, nil
+}
+
 // UpgradeToAltair updates input state to return the version Altair state.
 //
 // Spec code:
@@ -64,39 +104,7 @@ import (
 //	post.next_sync_committee = get_next_sync_committee(post)
 //	return post
 func UpgradeToAltair(ctx context.Context, state state.BeaconState) (state.BeaconState, error) {
-	epoch := time.CurrentEpoch(state)
-
-	numValidators := state.NumValidators()
-	s := &ethpb.BeaconStateAltair{
-		GenesisTime:           uint64(state.GenesisTime().Unix()),
-		GenesisValidatorsRoot: state.GenesisValidatorsRoot(),
-		Slot:                  state.Slot(),
-		Fork: &ethpb.Fork{
-			PreviousVersion: state.Fork().CurrentVersion,
-			CurrentVersion:  params.BeaconConfig().AltairForkVersion,
-			Epoch:           epoch,
-		},
-		LatestBlockHeader:           state.LatestBlockHeader(),
-		BlockRoots:                  state.BlockRoots(),
-		StateRoots:                  state.StateRoots(),
-		HistoricalRoots:             state.HistoricalRoots(),
-		Eth1Data:                    state.Eth1Data(),
-		Eth1DataVotes:               state.Eth1DataVotes(),
-		Eth1DepositIndex:            state.Eth1DepositIndex(),
-		Validators:                  state.Validators(),
-		Balances:                    state.Balances(),
-		RandaoMixes:                 state.RandaoMixes(),
-		Slashings:                   state.Slashings(),
-		PreviousEpochParticipation:  make([]byte, numValidators),
-		CurrentEpochParticipation:   make([]byte, numValidators),
-		JustificationBits:           state.JustificationBits(),
-		PreviousJustifiedCheckpoint: state.PreviousJustifiedCheckpoint(),
-		CurrentJustifiedCheckpoint:  state.CurrentJustifiedCheckpoint(),
-		FinalizedCheckpoint:         state.FinalizedCheckpoint(),
-		InactivityScores:            make([]uint64, numValidators),
-	}
-
-	newState, err := state_native.InitializeFromProtoUnsafeAltair(s)
+	newState, err := ConvertToAltair(state)
 	if err != nil {
 		return nil, err
 	}

beacon-chain/core/blocks/attester_slashing.go

@@ -5,6 +5,7 @@ import (
 	"sort"
 
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/validators"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v6/container/slice"
@@ -39,11 +40,11 @@ func ProcessAttesterSlashings(
 	ctx context.Context,
 	beaconState state.BeaconState,
 	slashings []ethpb.AttSlashing,
-	slashFunc slashValidatorFunc,
+	exitInfo *validators.ExitInfo,
 ) (state.BeaconState, error) {
 	var err error
 	for _, slashing := range slashings {
-		beaconState, err = ProcessAttesterSlashing(ctx, beaconState, slashing, slashFunc)
+		beaconState, err = ProcessAttesterSlashing(ctx, beaconState, slashing, exitInfo)
 		if err != nil {
 			return nil, err
 		}
@@ -56,7 +57,7 @@ func ProcessAttesterSlashing(
 	ctx context.Context,
 	beaconState state.BeaconState,
 	slashing ethpb.AttSlashing,
-	slashFunc slashValidatorFunc,
+	exitInfo *validators.ExitInfo,
 ) (state.BeaconState, error) {
 	if err := VerifyAttesterSlashing(ctx, beaconState, slashing); err != nil {
 		return nil, errors.Wrap(err, "could not verify attester slashing")
@@ -75,10 +76,9 @@ func ProcessAttesterSlashing(
 			return nil, err
 		}
 		if helpers.IsSlashableValidator(val.ActivationEpoch(), val.WithdrawableEpoch(), val.Slashed(), currentEpoch) {
-			beaconState, err = slashFunc(ctx, beaconState, primitives.ValidatorIndex(validatorIndex))
+			beaconState, err = validators.SlashValidator(ctx, beaconState, primitives.ValidatorIndex(validatorIndex), exitInfo)
 			if err != nil {
-				return nil, errors.Wrapf(err, "could not slash validator index %d",
-					validatorIndex)
+				return nil, errors.Wrapf(err, "could not slash validator index %d", validatorIndex)
 			}
 			slashedAny = true
 		}

beacon-chain/core/blocks/attester_slashing_test.go

@@ -4,6 +4,7 @@ import (
 	"testing"
 
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/blocks"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/signing"
 	v "github.com/OffchainLabs/prysm/v6/beacon-chain/core/validators"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
@@ -44,11 +45,10 @@ func TestProcessAttesterSlashings_DataNotSlashable(t *testing.T) {
 				Target: &ethpb.Checkpoint{Epoch: 1}},
 		})}}
 
-	var registry []*ethpb.Validator
 	currentSlot := primitives.Slot(0)
 
 	beaconState, err := state_native.InitializeFromProtoPhase0(&ethpb.BeaconState{
-		Validators: registry,
+		Validators: []*ethpb.Validator{{}},
 		Slot:       currentSlot,
 	})
 	require.NoError(t, err)
@@ -62,16 +62,15 @@ func TestProcessAttesterSlashings_DataNotSlashable(t *testing.T) {
 	for i, s := range b.Block.Body.AttesterSlashings {
 		ss[i] = s
 	}
-	_, err = blocks.ProcessAttesterSlashings(t.Context(), beaconState, ss, v.SlashValidator)
+	_, err = blocks.ProcessAttesterSlashings(t.Context(), beaconState, ss, v.ExitInformation(beaconState))
 	assert.ErrorContains(t, "attestations are not slashable", err)
 }
 
 func TestProcessAttesterSlashings_IndexedAttestationFailedToVerify(t *testing.T) {
-	var registry []*ethpb.Validator
 	currentSlot := primitives.Slot(0)
 
 	beaconState, err := state_native.InitializeFromProtoPhase0(&ethpb.BeaconState{
-		Validators: registry,
+		Validators: []*ethpb.Validator{{}},
 		Slot:       currentSlot,
 	})
 	require.NoError(t, err)
@@ -101,7 +100,7 @@ func TestProcessAttesterSlashings_IndexedAttestationFailedToVerify(t *testing.T)
 	for i, s := range b.Block.Body.AttesterSlashings {
 		ss[i] = s
 	}
-	_, err = blocks.ProcessAttesterSlashings(t.Context(), beaconState, ss, v.SlashValidator)
+	_, err = blocks.ProcessAttesterSlashings(t.Context(), beaconState, ss, v.ExitInformation(beaconState))
 	assert.ErrorContains(t, "validator indices count exceeds MAX_VALIDATORS_PER_COMMITTEE", err)
 }
 
@@ -243,7 +242,7 @@ func TestProcessAttesterSlashings_AppliesCorrectStatus(t *testing.T) {
 			currentSlot := 2 * params.BeaconConfig().SlotsPerEpoch
 			require.NoError(t, tc.st.SetSlot(currentSlot))
 
-			newState, err := blocks.ProcessAttesterSlashings(t.Context(), tc.st, []ethpb.AttSlashing{tc.slashing}, v.SlashValidator)
+			newState, err := blocks.ProcessAttesterSlashings(t.Context(), tc.st, []ethpb.AttSlashing{tc.slashing}, v.ExitInformation(tc.st))
 			require.NoError(t, err)
 			newRegistry := newState.Validators()
 
@@ -265,3 +264,83 @@ func TestProcessAttesterSlashings_AppliesCorrectStatus(t *testing.T) {
 		})
 	}
 }
+
+func TestProcessAttesterSlashing_ExitEpochGetsUpdated(t *testing.T) {
+	st, keys := util.DeterministicGenesisStateElectra(t, 8)
+	bal, err := helpers.TotalActiveBalance(st)
+	require.NoError(t, err)
+	perEpochChurn := helpers.ActivationExitChurnLimit(primitives.Gwei(bal))
+	vals := st.Validators()
+
+	// We set the total effective balance of slashed validators
+	// higher than the churn limit for a single epoch.
+	vals[0].EffectiveBalance = uint64(perEpochChurn / 3)
+	vals[1].EffectiveBalance = uint64(perEpochChurn / 3)
+	vals[2].EffectiveBalance = uint64(perEpochChurn / 3)
+	vals[3].EffectiveBalance = uint64(perEpochChurn / 3)
+	require.NoError(t, st.SetValidators(vals))
+
+	sl1att1 := util.HydrateIndexedAttestationElectra(&ethpb.IndexedAttestationElectra{
+		Data: &ethpb.AttestationData{
+			Source: &ethpb.Checkpoint{Epoch: 1},
+		},
+		AttestingIndices: []uint64{0, 1},
+	})
+	sl1att2 := util.HydrateIndexedAttestationElectra(&ethpb.IndexedAttestationElectra{
+		AttestingIndices: []uint64{0, 1},
+	})
+	slashing1 := &ethpb.AttesterSlashingElectra{
+		Attestation_1: sl1att1,
+		Attestation_2: sl1att2,
+	}
+	sl2att1 := util.HydrateIndexedAttestationElectra(&ethpb.IndexedAttestationElectra{
+		Data: &ethpb.AttestationData{
+			Source: &ethpb.Checkpoint{Epoch: 1},
+		},
+		AttestingIndices: []uint64{2, 3},
+	})
+	sl2att2 := util.HydrateIndexedAttestationElectra(&ethpb.IndexedAttestationElectra{
+		AttestingIndices: []uint64{2, 3},
+	})
+	slashing2 := &ethpb.AttesterSlashingElectra{
+		Attestation_1: sl2att1,
+		Attestation_2: sl2att2,
+	}
+
+	domain, err := signing.Domain(st.Fork(), 0, params.BeaconConfig().DomainBeaconAttester, st.GenesisValidatorsRoot())
+	require.NoError(t, err)
+
+	signingRoot, err := signing.ComputeSigningRoot(sl1att1.GetData(), domain)
+	assert.NoError(t, err, "Could not get signing root of beacon block header")
+	sig0 := keys[0].Sign(signingRoot[:])
+	sig1 := keys[1].Sign(signingRoot[:])
+	aggregateSig := bls.AggregateSignatures([]bls.Signature{sig0, sig1})
+	sl1att1.Signature = aggregateSig.Marshal()
+
+	signingRoot, err = signing.ComputeSigningRoot(sl1att2.GetData(), domain)
+	assert.NoError(t, err, "Could not get signing root of beacon block header")
+	sig0 = keys[0].Sign(signingRoot[:])
+	sig1 = keys[1].Sign(signingRoot[:])
+	aggregateSig = bls.AggregateSignatures([]bls.Signature{sig0, sig1})
+	sl1att2.Signature = aggregateSig.Marshal()
+
+	signingRoot, err = signing.ComputeSigningRoot(sl2att1.GetData(), domain)
+	assert.NoError(t, err, "Could not get signing root of beacon block header")
+	sig0 = keys[2].Sign(signingRoot[:])
+	sig1 = keys[3].Sign(signingRoot[:])
+	aggregateSig = bls.AggregateSignatures([]bls.Signature{sig0, sig1})
+	sl2att1.Signature = aggregateSig.Marshal()
+
+	signingRoot, err = signing.ComputeSigningRoot(sl2att2.GetData(), domain)
+	assert.NoError(t, err, "Could not get signing root of beacon block header")
+	sig0 = keys[2].Sign(signingRoot[:])
+	sig1 = keys[3].Sign(signingRoot[:])
+	aggregateSig = bls.AggregateSignatures([]bls.Signature{sig0, sig1})
+	sl2att2.Signature = aggregateSig.Marshal()
+
+	exitInfo := v.ExitInformation(st)
+	assert.Equal(t, primitives.Epoch(0), exitInfo.HighestExitEpoch)
+	_, err = blocks.ProcessAttesterSlashings(t.Context(), st, []ethpb.AttSlashing{slashing1, slashing2}, exitInfo)
+	require.NoError(t, err)
+	assert.Equal(t, primitives.Epoch(6), exitInfo.HighestExitEpoch)
+}

beacon-chain/core/blocks/block_operations_fuzz_test.go

@@ -191,7 +191,7 @@ func TestFuzzProcessProposerSlashings_10000(t *testing.T) {
 		fuzzer.Fuzz(p)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
 		require.NoError(t, err)
-		r, err := ProcessProposerSlashings(ctx, s, []*ethpb.ProposerSlashing{p}, v.SlashValidator)
+		r, err := ProcessProposerSlashings(ctx, s, []*ethpb.ProposerSlashing{p}, v.ExitInformation(s))
 		if err != nil && r != nil {
 			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and slashing: %v", r, err, state, p)
 		}
@@ -224,7 +224,7 @@ func TestFuzzProcessAttesterSlashings_10000(t *testing.T) {
 		fuzzer.Fuzz(a)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
 		require.NoError(t, err)
-		r, err := ProcessAttesterSlashings(ctx, s, []ethpb.AttSlashing{a}, v.SlashValidator)
+		r, err := ProcessAttesterSlashings(ctx, s, []ethpb.AttSlashing{a}, v.ExitInformation(s))
 		if err != nil && r != nil {
 			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and slashing: %v", r, err, state, a)
 		}
@@ -334,7 +334,7 @@ func TestFuzzProcessVoluntaryExits_10000(t *testing.T) {
 		fuzzer.Fuzz(e)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
 		require.NoError(t, err)
-		r, err := ProcessVoluntaryExits(ctx, s, []*ethpb.SignedVoluntaryExit{e})
+		r, err := ProcessVoluntaryExits(ctx, s, []*ethpb.SignedVoluntaryExit{e}, v.ExitInformation(s))
 		if err != nil && r != nil {
 			t.Fatalf("return value should be nil on err. found: %v on error: %v for state: %v and exit: %v", r, err, state, e)
 		}
@@ -351,7 +351,7 @@ func TestFuzzProcessVoluntaryExitsNoVerify_10000(t *testing.T) {
 		fuzzer.Fuzz(e)
 		s, err := state_native.InitializeFromProtoUnsafePhase0(state)
 		require.NoError(t, err)
-		r, err := ProcessVoluntaryExits(t.Context(), s, []*ethpb.SignedVoluntaryExit{e})
+		r, err := ProcessVoluntaryExits(t.Context(), s, []*ethpb.SignedVoluntaryExit{e}, v.ExitInformation(s))
 		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, e)
 		}

beacon-chain/core/blocks/block_regression_test.go

@@ -94,7 +94,7 @@ func TestProcessAttesterSlashings_RegressionSlashableIndices(t *testing.T) {
 	for i, s := range b.Block.Body.AttesterSlashings {
 		ss[i] = s
 	}
-	newState, err := blocks.ProcessAttesterSlashings(t.Context(), beaconState, ss, v.SlashValidator)
+	newState, err := blocks.ProcessAttesterSlashings(t.Context(), beaconState, ss, v.ExitInformation(beaconState))
 	require.NoError(t, err)
 	newRegistry := newState.Validators()
 	if !newRegistry[expectedSlashedVal].Slashed {

beacon-chain/core/blocks/exit.go

@@ -9,7 +9,6 @@ import (
 	v "github.com/OffchainLabs/prysm/v6/beacon-chain/core/validators"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
 	"github.com/OffchainLabs/prysm/v6/config/params"
-	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v6/runtime/version"
 	"github.com/OffchainLabs/prysm/v6/time/slots"
@@ -50,13 +49,12 @@ func ProcessVoluntaryExits(
 	ctx context.Context,
 	beaconState state.BeaconState,
 	exits []*ethpb.SignedVoluntaryExit,
+	exitInfo *v.ExitInfo,
 ) (state.BeaconState, error) {
 	// Avoid calculating the epoch churn if no exits exist.
 	if len(exits) == 0 {
 		return beaconState, nil
 	}
-	maxExitEpoch, churn := v.MaxExitEpochAndChurn(beaconState)
-	var exitEpoch primitives.Epoch
 	for idx, exit := range exits {
 		if exit == nil || exit.Exit == nil {
 			return nil, errors.New("nil voluntary exit in block body")
@@ -68,15 +66,8 @@ func ProcessVoluntaryExits(
 		if err := VerifyExitAndSignature(val, beaconState, exit); err != nil {
 			return nil, errors.Wrapf(err, "could not verify exit %d", idx)
 		}
-		beaconState, exitEpoch, err = v.InitiateValidatorExit(ctx, beaconState, exit.Exit.ValidatorIndex, maxExitEpoch, churn)
-		if err == nil {
-			if exitEpoch > maxExitEpoch {
-				maxExitEpoch = exitEpoch
-				churn = 1
-			} else if exitEpoch == maxExitEpoch {
-				churn++
-			}
-		} else if !errors.Is(err, v.ErrValidatorAlreadyExited) {
+		beaconState, err = v.InitiateValidatorExit(ctx, beaconState, exit.Exit.ValidatorIndex, exitInfo)
+		if err != nil && !errors.Is(err, v.ErrValidatorAlreadyExited) {
 			return nil, err
 		}
 	}

beacon-chain/core/blocks/exit_test.go

@@ -7,6 +7,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/signing"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/time"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/validators"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
 	state_native "github.com/OffchainLabs/prysm/v6/beacon-chain/state/state-native"
 	"github.com/OffchainLabs/prysm/v6/config/params"
@@ -46,7 +47,7 @@ func TestProcessVoluntaryExits_NotActiveLongEnoughToExit(t *testing.T) {
 	}
 
 	want := "validator has not been active long enough to exit"
-	_, err = blocks.ProcessVoluntaryExits(t.Context(), state, b.Block.Body.VoluntaryExits)
+	_, err = blocks.ProcessVoluntaryExits(t.Context(), state, b.Block.Body.VoluntaryExits, validators.ExitInformation(state))
 	assert.ErrorContains(t, want, err)
 }
 
@@ -76,7 +77,7 @@ 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(t.Context(), state, b.Block.Body.VoluntaryExits)
+	_, err = blocks.ProcessVoluntaryExits(t.Context(), state, b.Block.Body.VoluntaryExits, validators.ExitInformation(state))
 	assert.ErrorContains(t, want, err)
 }
 
@@ -124,7 +125,7 @@ func TestProcessVoluntaryExits_AppliesCorrectStatus(t *testing.T) {
 		},
 	}
 
-	newState, err := blocks.ProcessVoluntaryExits(t.Context(), state, b.Block.Body.VoluntaryExits)
+	newState, err := blocks.ProcessVoluntaryExits(t.Context(), state, b.Block.Body.VoluntaryExits, validators.ExitInformation(state))
 	require.NoError(t, err, "Could not process exits")
 	newRegistry := newState.Validators()
 	if newRegistry[0].ExitEpoch != helpers.ActivationExitEpoch(primitives.Epoch(state.Slot()/params.BeaconConfig().SlotsPerEpoch)) {

beacon-chain/core/blocks/genesis.go

@@ -184,45 +184,54 @@ func NewGenesisBlockForState(ctx context.Context, st state.BeaconState) (interfa
 		})
 	case *ethpb.BeaconStateElectra:
 		return blocks.NewSignedBeaconBlock(&ethpb.SignedBeaconBlockElectra{
-			Block: &ethpb.BeaconBlockElectra{
-				ParentRoot: params.BeaconConfig().ZeroHash[:],
-				StateRoot:  root[:],
-				Body: &ethpb.BeaconBlockBodyElectra{
-					RandaoReveal: make([]byte, 96),
-					Eth1Data: &ethpb.Eth1Data{
-						DepositRoot: make([]byte, 32),
-						BlockHash:   make([]byte, 32),
-					},
-					Graffiti: make([]byte, 32),
-					SyncAggregate: &ethpb.SyncAggregate{
-						SyncCommitteeBits:      make([]byte, fieldparams.SyncCommitteeLength/8),
-						SyncCommitteeSignature: make([]byte, fieldparams.BLSSignatureLength),
-					},
-					ExecutionPayload: &enginev1.ExecutionPayloadDeneb{
-						ParentHash:    make([]byte, 32),
-						FeeRecipient:  make([]byte, 20),
-						StateRoot:     make([]byte, 32),
-						ReceiptsRoot:  make([]byte, 32),
-						LogsBloom:     make([]byte, 256),
-						PrevRandao:    make([]byte, 32),
-						ExtraData:     make([]byte, 0),
-						BaseFeePerGas: make([]byte, 32),
-						BlockHash:     make([]byte, 32),
-						Transactions:  make([][]byte, 0),
-						Withdrawals:   make([]*enginev1.Withdrawal, 0),
-					},
-					BlsToExecutionChanges: make([]*ethpb.SignedBLSToExecutionChange, 0),
-					BlobKzgCommitments:    make([][]byte, 0),
-					ExecutionRequests: &enginev1.ExecutionRequests{
-						Withdrawals:    make([]*enginev1.WithdrawalRequest, 0),
-						Deposits:       make([]*enginev1.DepositRequest, 0),
-						Consolidations: make([]*enginev1.ConsolidationRequest, 0),
-					},
-				},
-			},
+			Block:     electraGenesisBlock(root),
+			Signature: params.BeaconConfig().EmptySignature[:],
+		})
+	case *ethpb.BeaconStateFulu:
+		return blocks.NewSignedBeaconBlock(&ethpb.SignedBeaconBlockFulu{
+			Block:     electraGenesisBlock(root),
 			Signature: params.BeaconConfig().EmptySignature[:],
 		})
 	default:
 		return nil, ErrUnrecognizedState
 	}
 }
+
+func electraGenesisBlock(root [fieldparams.RootLength]byte) *ethpb.BeaconBlockElectra {
+	return &ethpb.BeaconBlockElectra{
+		ParentRoot: params.BeaconConfig().ZeroHash[:],
+		StateRoot:  root[:],
+		Body: &ethpb.BeaconBlockBodyElectra{
+			RandaoReveal: make([]byte, 96),
+			Eth1Data: &ethpb.Eth1Data{
+				DepositRoot: make([]byte, 32),
+				BlockHash:   make([]byte, 32),
+			},
+			Graffiti: make([]byte, 32),
+			SyncAggregate: &ethpb.SyncAggregate{
+				SyncCommitteeBits:      make([]byte, fieldparams.SyncCommitteeLength/8),
+				SyncCommitteeSignature: make([]byte, fieldparams.BLSSignatureLength),
+			},
+			ExecutionPayload: &enginev1.ExecutionPayloadDeneb{
+				ParentHash:    make([]byte, 32),
+				FeeRecipient:  make([]byte, 20),
+				StateRoot:     make([]byte, 32),
+				ReceiptsRoot:  make([]byte, 32),
+				LogsBloom:     make([]byte, 256),
+				PrevRandao:    make([]byte, 32),
+				ExtraData:     make([]byte, 0),
+				BaseFeePerGas: make([]byte, 32),
+				BlockHash:     make([]byte, 32),
+				Transactions:  make([][]byte, 0),
+				Withdrawals:   make([]*enginev1.Withdrawal, 0),
+			},
+			BlsToExecutionChanges: make([]*ethpb.SignedBLSToExecutionChange, 0),
+			BlobKzgCommitments:    make([][]byte, 0),
+			ExecutionRequests: &enginev1.ExecutionRequests{
+				Withdrawals:    make([]*enginev1.WithdrawalRequest, 0),
+				Deposits:       make([]*enginev1.DepositRequest, 0),
+				Consolidations: make([]*enginev1.ConsolidationRequest, 0),
+			},
+		},
+	}
+}

beacon-chain/core/blocks/proposer_slashing.go

@@ -7,9 +7,9 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/signing"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/time"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/validators"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
 	"github.com/OffchainLabs/prysm/v6/config/params"
-	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v6/time/slots"
 	"github.com/pkg/errors"
@@ -19,11 +19,6 @@ import (
 // ErrCouldNotVerifyBlockHeader is returned when a block header's signature cannot be verified.
 var ErrCouldNotVerifyBlockHeader = errors.New("could not verify beacon block header")
 
-type slashValidatorFunc func(
-	ctx context.Context,
-	st state.BeaconState,
-	vid primitives.ValidatorIndex) (state.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.
@@ -54,11 +49,11 @@ func ProcessProposerSlashings(
 	ctx context.Context,
 	beaconState state.BeaconState,
 	slashings []*ethpb.ProposerSlashing,
-	slashFunc slashValidatorFunc,
+	exitInfo *validators.ExitInfo,
 ) (state.BeaconState, error) {
 	var err error
 	for _, slashing := range slashings {
-		beaconState, err = ProcessProposerSlashing(ctx, beaconState, slashing, slashFunc)
+		beaconState, err = ProcessProposerSlashing(ctx, beaconState, slashing, exitInfo)
 		if err != nil {
 			return nil, err
 		}
@@ -71,7 +66,7 @@ func ProcessProposerSlashing(
 	ctx context.Context,
 	beaconState state.BeaconState,
 	slashing *ethpb.ProposerSlashing,
-	slashFunc slashValidatorFunc,
+	exitInfo *validators.ExitInfo,
 ) (state.BeaconState, error) {
 	var err error
 	if slashing == nil {
@@ -80,7 +75,7 @@ func ProcessProposerSlashing(
 	if err = VerifyProposerSlashing(beaconState, slashing); err != nil {
 		return nil, errors.Wrap(err, "could not verify proposer slashing")
 	}
-	beaconState, err = slashFunc(ctx, beaconState, slashing.Header_1.Header.ProposerIndex)
+	beaconState, err = validators.SlashValidator(ctx, beaconState, slashing.Header_1.Header.ProposerIndex, exitInfo)
 	if err != nil {
 		return nil, errors.Wrapf(err, "could not slash proposer index %d", slashing.Header_1.Header.ProposerIndex)
 	}

beacon-chain/core/blocks/proposer_slashing_test.go

@@ -50,7 +50,7 @@ func TestProcessProposerSlashings_UnmatchedHeaderSlots(t *testing.T) {
 		},
 	}
 	want := "mismatched header slots"
-	_, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, b.Block.Body.ProposerSlashings, v.SlashValidator)
+	_, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, b.Block.Body.ProposerSlashings, v.ExitInformation(beaconState))
 	assert.ErrorContains(t, want, err)
 }
 
@@ -83,7 +83,7 @@ func TestProcessProposerSlashings_SameHeaders(t *testing.T) {
 		},
 	}
 	want := "expected slashing headers to differ"
-	_, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, b.Block.Body.ProposerSlashings, v.SlashValidator)
+	_, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, b.Block.Body.ProposerSlashings, v.ExitInformation(beaconState))
 	assert.ErrorContains(t, want, err)
 }
 
@@ -133,7 +133,7 @@ func TestProcessProposerSlashings_ValidatorNotSlashable(t *testing.T) {
 		"validator with key %#x is not slashable",
 		bytesutil.ToBytes48(beaconState.Validators()[0].PublicKey),
 	)
-	_, err = blocks.ProcessProposerSlashings(t.Context(), beaconState, b.Block.Body.ProposerSlashings, v.SlashValidator)
+	_, err = blocks.ProcessProposerSlashings(t.Context(), beaconState, b.Block.Body.ProposerSlashings, v.ExitInformation(beaconState))
 	assert.ErrorContains(t, want, err)
 }
 
@@ -172,7 +172,7 @@ func TestProcessProposerSlashings_AppliesCorrectStatus(t *testing.T) {
 	block := util.NewBeaconBlock()
 	block.Block.Body.ProposerSlashings = slashings
 
-	newState, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, block.Block.Body.ProposerSlashings, v.SlashValidator)
+	newState, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, block.Block.Body.ProposerSlashings, v.ExitInformation(beaconState))
 	require.NoError(t, err)
 
 	newStateVals := newState.Validators()
@@ -220,7 +220,7 @@ func TestProcessProposerSlashings_AppliesCorrectStatusAltair(t *testing.T) {
 	block := util.NewBeaconBlock()
 	block.Block.Body.ProposerSlashings = slashings
 
-	newState, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, block.Block.Body.ProposerSlashings, v.SlashValidator)
+	newState, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, block.Block.Body.ProposerSlashings, v.ExitInformation(beaconState))
 	require.NoError(t, err)
 
 	newStateVals := newState.Validators()
@@ -268,7 +268,7 @@ func TestProcessProposerSlashings_AppliesCorrectStatusBellatrix(t *testing.T) {
 	block := util.NewBeaconBlock()
 	block.Block.Body.ProposerSlashings = slashings
 
-	newState, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, block.Block.Body.ProposerSlashings, v.SlashValidator)
+	newState, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, block.Block.Body.ProposerSlashings, v.ExitInformation(beaconState))
 	require.NoError(t, err)
 
 	newStateVals := newState.Validators()
@@ -316,7 +316,7 @@ func TestProcessProposerSlashings_AppliesCorrectStatusCapella(t *testing.T) {
 	block := util.NewBeaconBlock()
 	block.Block.Body.ProposerSlashings = slashings
 
-	newState, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, block.Block.Body.ProposerSlashings, v.SlashValidator)
+	newState, err := blocks.ProcessProposerSlashings(t.Context(), beaconState, block.Block.Body.ProposerSlashings, v.ExitInformation(beaconState))
 	require.NoError(t, err)
 
 	newStateVals := newState.Validators()

beacon-chain/core/electra/registry_updates.go

@@ -84,8 +84,8 @@ func ProcessRegistryUpdates(ctx context.Context, st state.BeaconState) error {
 	// Handle validator ejections.
 	for _, idx := range eligibleForEjection {
 		var err error
-		// exitQueueEpoch and churn arguments are not used in electra.
-		st, _, err = validators.InitiateValidatorExit(ctx, st, idx, 0 /*exitQueueEpoch*/, 0 /*churn*/)
+		// exit info is not used in electra
+		st, err = validators.InitiateValidatorExit(ctx, st, idx, &validators.ExitInfo{})
 		if err != nil && !errors.Is(err, validators.ErrValidatorAlreadyExited) {
 			return fmt.Errorf("failed to initiate validator exit at index %d: %w", idx, err)
 		}

beacon-chain/core/electra/transition_no_verify_sig.go

@@ -4,6 +4,7 @@ import (
 	"context"
 
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/blocks"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
 	v "github.com/OffchainLabs/prysm/v6/beacon-chain/core/validators"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
@@ -46,18 +47,21 @@ var (
 //      # [New in Electra:EIP7251]
 //      for_ops(body.execution_payload.consolidation_requests, process_consolidation_request)
 
-func ProcessOperations(
-	ctx context.Context,
-	st state.BeaconState,
-	block interfaces.ReadOnlyBeaconBlock) (state.BeaconState, error) {
+func ProcessOperations(ctx context.Context, st state.BeaconState, block interfaces.ReadOnlyBeaconBlock) (state.BeaconState, error) {
+	var err error
+
 	// 6110 validations are in VerifyOperationLengths
 	bb := block.Body()
 	// Electra extends the altair operations.
-	st, err := ProcessProposerSlashings(ctx, st, bb.ProposerSlashings(), v.SlashValidator)
+	exitInfo := v.ExitInformation(st)
+	if err := helpers.UpdateTotalActiveBalanceCache(st, exitInfo.TotalActiveBalance); err != nil {
+		return nil, errors.Wrap(err, "could not update total active balance cache")
+	}
+	st, err = ProcessProposerSlashings(ctx, st, bb.ProposerSlashings(), exitInfo)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not process altair proposer slashing")
 	}
-	st, err = ProcessAttesterSlashings(ctx, st, bb.AttesterSlashings(), v.SlashValidator)
+	st, err = ProcessAttesterSlashings(ctx, st, bb.AttesterSlashings(), exitInfo)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not process altair attester slashing")
 	}
@@ -68,7 +72,7 @@ func ProcessOperations(
 	if _, err := ProcessDeposits(ctx, st, bb.Deposits()); err != nil { // new in electra
 		return nil, errors.Wrap(err, "could not process altair deposit")
 	}
-	st, err = ProcessVoluntaryExits(ctx, st, bb.VoluntaryExits())
+	st, err = ProcessVoluntaryExits(ctx, st, bb.VoluntaryExits(), exitInfo)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not process voluntary exits")
 	}

beacon-chain/core/electra/upgrade.go

@@ -15,6 +15,129 @@ import (
 	"github.com/pkg/errors"
 )
 
+// ConvertToElectra converts a Deneb beacon state to an Electra beacon state. It does not perform any fork logic.
+func ConvertToElectra(beaconState state.BeaconState) (state.BeaconState, error) {
+	currentSyncCommittee, err := beaconState.CurrentSyncCommittee()
+	if err != nil {
+		return nil, err
+	}
+	nextSyncCommittee, err := beaconState.NextSyncCommittee()
+	if err != nil {
+		return nil, err
+	}
+	prevEpochParticipation, err := beaconState.PreviousEpochParticipation()
+	if err != nil {
+		return nil, err
+	}
+	currentEpochParticipation, err := beaconState.CurrentEpochParticipation()
+	if err != nil {
+		return nil, err
+	}
+	inactivityScores, err := beaconState.InactivityScores()
+	if err != nil {
+		return nil, err
+	}
+	payloadHeader, err := beaconState.LatestExecutionPayloadHeader()
+	if err != nil {
+		return nil, err
+	}
+	txRoot, err := payloadHeader.TransactionsRoot()
+	if err != nil {
+		return nil, err
+	}
+	wdRoot, err := payloadHeader.WithdrawalsRoot()
+	if err != nil {
+		return nil, err
+	}
+	wi, err := beaconState.NextWithdrawalIndex()
+	if err != nil {
+		return nil, err
+	}
+	vi, err := beaconState.NextWithdrawalValidatorIndex()
+	if err != nil {
+		return nil, err
+	}
+	summaries, err := beaconState.HistoricalSummaries()
+	if err != nil {
+		return nil, err
+	}
+	excessBlobGas, err := payloadHeader.ExcessBlobGas()
+	if err != nil {
+		return nil, err
+	}
+	blobGasUsed, err := payloadHeader.BlobGasUsed()
+	if err != nil {
+		return nil, err
+	}
+
+	s := &ethpb.BeaconStateElectra{
+		GenesisTime:           uint64(beaconState.GenesisTime().Unix()),
+		GenesisValidatorsRoot: beaconState.GenesisValidatorsRoot(),
+		Slot:                  beaconState.Slot(),
+		Fork: &ethpb.Fork{
+			PreviousVersion: beaconState.Fork().CurrentVersion,
+			CurrentVersion:  params.BeaconConfig().ElectraForkVersion,
+			Epoch:           time.CurrentEpoch(beaconState),
+		},
+		LatestBlockHeader:           beaconState.LatestBlockHeader(),
+		BlockRoots:                  beaconState.BlockRoots(),
+		StateRoots:                  beaconState.StateRoots(),
+		HistoricalRoots:             beaconState.HistoricalRoots(),
+		Eth1Data:                    beaconState.Eth1Data(),
+		Eth1DataVotes:               beaconState.Eth1DataVotes(),
+		Eth1DepositIndex:            beaconState.Eth1DepositIndex(),
+		Validators:                  beaconState.Validators(),
+		Balances:                    beaconState.Balances(),
+		RandaoMixes:                 beaconState.RandaoMixes(),
+		Slashings:                   beaconState.Slashings(),
+		PreviousEpochParticipation:  prevEpochParticipation,
+		CurrentEpochParticipation:   currentEpochParticipation,
+		JustificationBits:           beaconState.JustificationBits(),
+		PreviousJustifiedCheckpoint: beaconState.PreviousJustifiedCheckpoint(),
+		CurrentJustifiedCheckpoint:  beaconState.CurrentJustifiedCheckpoint(),
+		FinalizedCheckpoint:         beaconState.FinalizedCheckpoint(),
+		InactivityScores:            inactivityScores,
+		CurrentSyncCommittee:        currentSyncCommittee,
+		NextSyncCommittee:           nextSyncCommittee,
+		LatestExecutionPayloadHeader: &enginev1.ExecutionPayloadHeaderDeneb{
+			ParentHash:       payloadHeader.ParentHash(),
+			FeeRecipient:     payloadHeader.FeeRecipient(),
+			StateRoot:        payloadHeader.StateRoot(),
+			ReceiptsRoot:     payloadHeader.ReceiptsRoot(),
+			LogsBloom:        payloadHeader.LogsBloom(),
+			PrevRandao:       payloadHeader.PrevRandao(),
+			BlockNumber:      payloadHeader.BlockNumber(),
+			GasLimit:         payloadHeader.GasLimit(),
+			GasUsed:          payloadHeader.GasUsed(),
+			Timestamp:        payloadHeader.Timestamp(),
+			ExtraData:        payloadHeader.ExtraData(),
+			BaseFeePerGas:    payloadHeader.BaseFeePerGas(),
+			BlockHash:        payloadHeader.BlockHash(),
+			TransactionsRoot: txRoot,
+			WithdrawalsRoot:  wdRoot,
+			ExcessBlobGas:    excessBlobGas,
+			BlobGasUsed:      blobGasUsed,
+		},
+		NextWithdrawalIndex:          wi,
+		NextWithdrawalValidatorIndex: vi,
+		HistoricalSummaries:          summaries,
+
+		DepositRequestsStartIndex:  params.BeaconConfig().UnsetDepositRequestsStartIndex,
+		DepositBalanceToConsume:    0,
+		EarliestConsolidationEpoch: helpers.ActivationExitEpoch(slots.ToEpoch(beaconState.Slot())),
+		PendingDeposits:            make([]*ethpb.PendingDeposit, 0),
+		PendingPartialWithdrawals:  make([]*ethpb.PendingPartialWithdrawal, 0),
+		PendingConsolidations:      make([]*ethpb.PendingConsolidation, 0),
+	}
+
+	// need to cast the beaconState to use in helper functions
+	post, err := state_native.InitializeFromProtoUnsafeElectra(s)
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to initialize post electra beaconState")
+	}
+	return post, nil
+}
+
 // UpgradeToElectra updates inputs a generic state to return the version Electra state.
 //
 // nolint:dupword

beacon-chain/core/electra/withdrawals.go

@@ -147,9 +147,8 @@ func ProcessWithdrawalRequests(ctx context.Context, st state.BeaconState, wrs []
 		if isFullExitRequest {
 			// Only exit validator if it has no pending withdrawals in the queue
 			if pendingBalanceToWithdraw == 0 {
-				maxExitEpoch, churn := validators.MaxExitEpochAndChurn(st)
 				var err error
-				st, _, err = validators.InitiateValidatorExit(ctx, st, vIdx, maxExitEpoch, churn)
+				st, err = validators.InitiateValidatorExit(ctx, st, vIdx, validators.ExitInformation(st))
 				if err != nil {
 					return nil, err
 				}

beacon-chain/core/epoch/epoch_processing.go

@@ -99,8 +99,7 @@ func ProcessRegistryUpdates(ctx context.Context, st state.BeaconState) (state.Be
 	for _, idx := range eligibleForEjection {
 		// Here is fine to do a quadratic loop since this should
 		// barely happen
-		maxExitEpoch, churn := validators.MaxExitEpochAndChurn(st)
-		st, _, err = validators.InitiateValidatorExit(ctx, st, idx, maxExitEpoch, churn)
+		st, err = validators.InitiateValidatorExit(ctx, st, idx, validators.ExitInformation(st))
 		if err != nil && !errors.Is(err, validators.ErrValidatorAlreadyExited) {
 			return nil, errors.Wrapf(err, "could not initiate exit for validator %d", idx)
 		}

beacon-chain/core/execution/BUILD.bazel

@@ -7,6 +7,7 @@ go_library(
     visibility = [
         "//beacon-chain:__subpackages__",
         "//cmd/prysmctl/testnet:__pkg__",
+        "//consensus-types/hdiff:__subpackages__",
         "//testing/spectest:__subpackages__",
         "//validator/client:__pkg__",
     ],

beacon-chain/core/fulu/BUILD.bazel

@@ -15,6 +15,7 @@ go_library(
         "//beacon-chain/state:go_default_library",
         "//beacon-chain/state/state-native:go_default_library",
         "//config/params:go_default_library",
+        "//consensus-types/primitives:go_default_library",
         "//monitoring/tracing/trace:go_default_library",
         "//proto/engine/v1:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",

beacon-chain/core/fulu/transition.go

@@ -16,10 +16,10 @@ func ProcessEpoch(ctx context.Context, state state.BeaconState) error {
 	if err := electra.ProcessEpoch(ctx, state); err != nil {
 		return errors.Wrap(err, "could not process epoch in fulu transition")
 	}
-	return processProposerLookahead(ctx, state)
+	return ProcessProposerLookahead(ctx, state)
 }
 
-func processProposerLookahead(ctx context.Context, state state.BeaconState) error {
+func ProcessProposerLookahead(ctx context.Context, state state.BeaconState) error {
 	_, span := trace.StartSpan(ctx, "fulu.processProposerLookahead")
 	defer span.End()
 

beacon-chain/core/fulu/upgrade.go

@@ -8,6 +8,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
 	state_native "github.com/OffchainLabs/prysm/v6/beacon-chain/state/state-native"
 	"github.com/OffchainLabs/prysm/v6/config/params"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	enginev1 "github.com/OffchainLabs/prysm/v6/proto/engine/v1"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v6/time/slots"
@@ -17,6 +18,25 @@ import (
 // UpgradeToFulu updates inputs a generic state to return the version Fulu state.
 // https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/fork.md#upgrading-the-state
 func UpgradeToFulu(ctx context.Context, beaconState state.BeaconState) (state.BeaconState, error) {
+	s, err := ConvertToFulu(beaconState)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not convert to fulu")
+	}
+	proposerLookahead, err := helpers.InitializeProposerLookahead(ctx, beaconState, slots.ToEpoch(beaconState.Slot()))
+	if err != nil {
+		return nil, err
+	}
+	pl := make([]primitives.ValidatorIndex, len(proposerLookahead))
+	for i, v := range proposerLookahead {
+		pl[i] = primitives.ValidatorIndex(v)
+	}
+	if err := s.SetProposerLookahead(pl); err != nil {
+		return nil, errors.Wrap(err, "failed to set proposer lookahead")
+	}
+	return s, nil
+}
+
+func ConvertToFulu(beaconState state.BeaconState) (state.BeaconState, error) {
 	currentSyncCommittee, err := beaconState.CurrentSyncCommittee()
 	if err != nil {
 		return nil, err
@@ -105,11 +125,6 @@ func UpgradeToFulu(ctx context.Context, beaconState state.BeaconState) (state.Be
 	if err != nil {
 		return nil, err
 	}
-	proposerLookahead, err := helpers.InitializeProposerLookahead(ctx, beaconState, slots.ToEpoch(beaconState.Slot()))
-	if err != nil {
-		return nil, err
-	}
-
 	s := &ethpb.BeaconStateFulu{
 		GenesisTime:           uint64(beaconState.GenesisTime().Unix()),
 		GenesisValidatorsRoot: beaconState.GenesisValidatorsRoot(),
@@ -171,14 +186,6 @@ func UpgradeToFulu(ctx context.Context, beaconState state.BeaconState) (state.Be
 		PendingDeposits:               pendingDeposits,
 		PendingPartialWithdrawals:     pendingPartialWithdrawals,
 		PendingConsolidations:         pendingConsolidations,
-		ProposerLookahead:             proposerLookahead,
 	}
-
-	// Need to cast the beaconState to use in helper functions
-	post, err := state_native.InitializeFromProtoUnsafeFulu(s)
-	if err != nil {
-		return nil, errors.Wrap(err, "failed to initialize post fulu beaconState")
-	}
-
-	return post, nil
+	return state_native.InitializeFromProtoUnsafeFulu(s)
 }

beacon-chain/core/helpers/BUILD.bazel

@@ -10,6 +10,7 @@ go_library(
         "legacy.go",
         "metrics.go",
         "randao.go",
+        "ranges.go",
         "rewards_penalties.go",
         "shuffle.go",
         "sync_committee.go",
@@ -56,6 +57,7 @@ go_test(
         "private_access_fuzz_noop_test.go",  # keep
         "private_access_test.go",
         "randao_test.go",
+        "ranges_test.go",
         "rewards_penalties_test.go",
         "shuffle_test.go",
         "sync_committee_test.go",

beacon-chain/core/helpers/beacon_committee.go

@@ -317,23 +317,15 @@ func ProposerAssignments(ctx context.Context, state state.BeaconState, epoch pri
 	}
 
 	proposerAssignments := make(map[primitives.ValidatorIndex][]primitives.Slot)
-
-	originalStateSlot := state.Slot()
-
 	for slot := startSlot; slot < startSlot+params.BeaconConfig().SlotsPerEpoch; slot++ {
 		// Skip proposer assignment for genesis slot.
 		if slot == 0 {
 			continue
 		}
-		// Set the state's current slot.
-		if err := state.SetSlot(slot); err != nil {
-			return nil, err
-		}
-
 		// Determine the proposer index for the current slot.
-		i, err := BeaconProposerIndex(ctx, state)
+		i, err := BeaconProposerIndexAtSlot(ctx, state, slot)
 		if err != nil {
-			return nil, errors.Wrapf(err, "could not check proposer at slot %d", state.Slot())
+			return nil, errors.Wrapf(err, "could not check proposer at slot %d", slot)
 		}
 
 		// Append the slot to the proposer's assignments.
@@ -342,12 +334,6 @@ func ProposerAssignments(ctx context.Context, state state.BeaconState, epoch pri
 		}
 		proposerAssignments[i] = append(proposerAssignments[i], slot)
 	}
-
-	// Reset state back to its original slot.
-	if err := state.SetSlot(originalStateSlot); err != nil {
-		return nil, err
-	}
-
 	return proposerAssignments, nil
 }
 

beacon-chain/core/helpers/ranges.go

@@ -0,0 +1,62 @@
+package helpers
+
+import (
+	"fmt"
+	"slices"
+)
+
+// SortedSliceFromMap takes a map with uint64 keys and returns a sorted slice of the keys.
+func SortedSliceFromMap(toSort map[uint64]bool) []uint64 {
+	slice := make([]uint64, 0, len(toSort))
+	for key := range toSort {
+		slice = append(slice, key)
+	}
+
+	slices.Sort(slice)
+	return slice
+}
+
+// PrettySlice returns a pretty string representation of a sorted slice of uint64.
+// `sortedSlice` must be sorted in ascending order.
+// Example: [1,2,3,5,6,7,8,10] -> "1-3,5-8,10"
+func PrettySlice(sortedSlice []uint64) string {
+	if len(sortedSlice) == 0 {
+		return ""
+	}
+
+	var result string
+	start := sortedSlice[0]
+	end := sortedSlice[0]
+
+	for i := 1; i < len(sortedSlice); i++ {
+		if sortedSlice[i] == end+1 {
+			end = sortedSlice[i]
+			continue
+		}
+
+		if start == end {
+			result += fmt.Sprintf("%d,", start)
+			start = sortedSlice[i]
+			end = sortedSlice[i]
+			continue
+		}
+
+		result += fmt.Sprintf("%d-%d,", start, end)
+		start = sortedSlice[i]
+		end = sortedSlice[i]
+	}
+
+	if start == end {
+		result += fmt.Sprintf("%d", start)
+		return result
+	}
+
+	result += fmt.Sprintf("%d-%d", start, end)
+	return result
+}
+
+// SortedPrettySliceFromMap combines SortedSliceFromMap and PrettySlice to return a pretty string representation of the keys in a map.
+func SortedPrettySliceFromMap(toSort map[uint64]bool) string {
+	sorted := SortedSliceFromMap(toSort)
+	return PrettySlice(sorted)
+}

beacon-chain/core/helpers/ranges_test.go

@@ -0,0 +1,64 @@
+package helpers_test
+
+import (
+	"testing"
+
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
+	"github.com/OffchainLabs/prysm/v6/testing/require"
+)
+
+func TestSortedSliceFromMap(t *testing.T) {
+	input := map[uint64]bool{5: true, 3: true, 8: true, 1: true}
+	expected := []uint64{1, 3, 5, 8}
+
+	actual := helpers.SortedSliceFromMap(input)
+	require.Equal(t, len(expected), len(actual))
+
+	for i := range expected {
+		require.Equal(t, expected[i], actual[i])
+	}
+}
+
+func TestPrettySlice(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    []uint64
+		expected string
+	}{
+		{
+			name:     "empty slice",
+			input:    []uint64{},
+			expected: "",
+		},
+		{
+			name:     "only distinct elements",
+			input:    []uint64{1, 3, 5, 7, 9},
+			expected: "1,3,5,7,9",
+		},
+		{
+			name:     "single range",
+			input:    []uint64{1, 2, 3, 4, 5},
+			expected: "1-5",
+		},
+		{
+			name:     "multiple ranges and distinct elements",
+			input:    []uint64{1, 2, 3, 5, 6, 7, 8, 10, 12, 13, 14},
+			expected: "1-3,5-8,10,12-14",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			actual := helpers.PrettySlice(tt.input)
+			require.Equal(t, tt.expected, actual)
+		})
+	}
+}
+
+func TestSortedPrettySliceFromMap(t *testing.T) {
+	input := map[uint64]bool{5: true, 7: true, 8: true, 10: true}
+	expected := "5,7-8,10"
+
+	actual := helpers.SortedPrettySliceFromMap(input)
+	require.Equal(t, expected, actual)
+}

beacon-chain/core/helpers/rewards_penalties.go

@@ -87,6 +87,11 @@ func TotalActiveBalance(s state.ReadOnlyBeaconState) (uint64, error) {
 	return total, nil
 }
 
+// UpdateTotalActiveBalanceCache updates the cache with the given total active balance.
+func UpdateTotalActiveBalanceCache(s state.BeaconState, total uint64) error {
+	return balanceCache.AddTotalEffectiveBalance(s, total)
+}
+
 // IncreaseBalance increases validator with the given 'index' balance by 'delta' in Gwei.
 //
 // Spec pseudocode definition:

beacon-chain/core/helpers/rewards_penalties_test.go

@@ -297,3 +297,30 @@ func TestIncreaseBadBalance_NotOK(t *testing.T) {
 		require.ErrorContains(t, "addition overflows", helpers.IncreaseBalance(state, test.i, test.nb))
 	}
 }
+
+func TestUpdateTotalActiveBalanceCache(t *testing.T) {
+	helpers.ClearCache()
+
+	// Create a test state with some validators
+	validators := []*ethpb.Validator{
+		{EffectiveBalance: 32 * 1e9, ExitEpoch: params.BeaconConfig().FarFutureEpoch, ActivationEpoch: 0},
+		{EffectiveBalance: 32 * 1e9, ExitEpoch: params.BeaconConfig().FarFutureEpoch, ActivationEpoch: 0},
+		{EffectiveBalance: 31 * 1e9, ExitEpoch: params.BeaconConfig().FarFutureEpoch, ActivationEpoch: 0},
+	}
+	state, err := state_native.InitializeFromProtoPhase0(&ethpb.BeaconState{
+		Validators: validators,
+		Slot:       0,
+	})
+	require.NoError(t, err)
+
+	// Test updating cache with a specific total
+	testTotal := uint64(95 * 1e9) // 32 + 32 + 31 = 95
+	err = helpers.UpdateTotalActiveBalanceCache(state, testTotal)
+	require.NoError(t, err)
+
+	// Verify the cache was updated by retrieving the total active balance
+	// which should now return the cached value
+	cachedTotal, err := helpers.TotalActiveBalance(state)
+	require.NoError(t, err)
+	assert.Equal(t, testTotal, cachedTotal, "Cache should return the updated total")
+}

beacon-chain/core/helpers/sync_committee.go

@@ -21,6 +21,39 @@ var (
 	syncCommitteeCache = cache.NewSyncCommittee()
 )
 
+// CurrentPeriodPositions returns committee indices of the current period sync committee for input validators.
+func CurrentPeriodPositions(st state.BeaconState, indices []primitives.ValidatorIndex) ([][]primitives.CommitteeIndex, error) {
+	root, err := SyncPeriodBoundaryRoot(st)
+	if err != nil {
+		return nil, err
+	}
+	pos, err := syncCommitteeCache.CurrentPeriodPositions(root, indices)
+	if errors.Is(err, cache.ErrNonExistingSyncCommitteeKey) {
+		committee, err := st.CurrentSyncCommittee()
+		if err != nil {
+			return nil, err
+		}
+
+		// Fill in the cache on miss.
+		go func() {
+			if err := syncCommitteeCache.UpdatePositionsInCommittee(root, st); err != nil {
+				log.WithError(err).Error("Could not fill sync committee cache on miss")
+			}
+		}()
+
+		pos = make([][]primitives.CommitteeIndex, len(indices))
+		for i, idx := range indices {
+			pubkey := st.PubkeyAtIndex(idx)
+			pos[i] = findSubCommitteeIndices(pubkey[:], committee.Pubkeys)
+		}
+		return pos, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	return pos, nil
+}
+
 // IsCurrentPeriodSyncCommittee returns true if the input validator index belongs in the current period sync committee
 // along with the sync committee root.
 // 1. Checks if the public key exists in the sync committee cache

beacon-chain/core/helpers/sync_committee_test.go

@@ -17,6 +17,38 @@ import (
 	"github.com/OffchainLabs/prysm/v6/testing/require"
 )
 
+func TestCurrentPeriodPositions(t *testing.T) {
+	helpers.ClearCache()
+
+	validators := make([]*ethpb.Validator, params.BeaconConfig().SyncCommitteeSize)
+	syncCommittee := &ethpb.SyncCommittee{
+		Pubkeys: make([][]byte, params.BeaconConfig().SyncCommitteeSize),
+	}
+	for i := 0; i < len(validators); i++ {
+		k := make([]byte, 48)
+		copy(k, strconv.Itoa(i))
+		validators[i] = &ethpb.Validator{
+			PublicKey: k,
+		}
+		syncCommittee.Pubkeys[i] = bytesutil.PadTo(k, 48)
+	}
+	state, err := state_native.InitializeFromProtoAltair(&ethpb.BeaconStateAltair{
+		Validators: validators,
+	})
+	require.NoError(t, err)
+	require.NoError(t, state.SetCurrentSyncCommittee(syncCommittee))
+	require.NoError(t, state.SetNextSyncCommittee(syncCommittee))
+	require.NoError(t, err, helpers.SyncCommitteeCache().UpdatePositionsInCommittee([32]byte{}, state))
+
+	positions, err := helpers.CurrentPeriodPositions(state, []primitives.ValidatorIndex{0, 1})
+	require.NoError(t, err)
+	require.Equal(t, 2, len(positions))
+	require.Equal(t, 1, len(positions[0]))
+	assert.Equal(t, primitives.CommitteeIndex(0), positions[0][0])
+	require.Equal(t, 1, len(positions[1]))
+	assert.Equal(t, primitives.CommitteeIndex(1), positions[1][0])
+}
+
 func TestIsCurrentEpochSyncCommittee_UsingCache(t *testing.T) {
 	helpers.ClearCache()
 

beacon-chain/core/helpers/validators.go

@@ -309,23 +309,29 @@ func beaconProposerIndexAtSlotFulu(state state.ReadOnlyBeaconState, slot primiti
 	if err != nil {
 		return 0, errors.Wrap(err, "could not get proposer lookahead")
 	}
+	spe := params.BeaconConfig().SlotsPerEpoch
 	if e == stateEpoch {
-		return lookAhead[slot%params.BeaconConfig().SlotsPerEpoch], nil
+		return lookAhead[slot%spe], nil
 	}
 	// The caller is requesting the proposer for the next epoch
-	return lookAhead[slot%params.BeaconConfig().SlotsPerEpoch+params.BeaconConfig().SlotsPerEpoch], nil
+	return lookAhead[spe+slot%spe], nil
 }
 
 // BeaconProposerIndexAtSlot returns proposer index at the given slot from the
 // point of view of the given state as head state
 func BeaconProposerIndexAtSlot(ctx context.Context, state state.ReadOnlyBeaconState, slot primitives.Slot) (primitives.ValidatorIndex, error) {
-	if state.Version() >= version.Fulu {
-		return beaconProposerIndexAtSlotFulu(state, slot)
-	}
 	e := slots.ToEpoch(slot)
+	stateEpoch := slots.ToEpoch(state.Slot())
+	// Even if the state is post Fulu, we may request a past proposer index.
+	if state.Version() >= version.Fulu && e >= params.BeaconConfig().FuluForkEpoch {
+		// We can use the cached lookahead only for the current and the next epoch.
+		if e == stateEpoch || e == stateEpoch+1 {
+			return beaconProposerIndexAtSlotFulu(state, slot)
+		}
+	}
 	// The cache uses the state root of the previous epoch - minimum_seed_lookahead last slot as key. (e.g. Starting epoch 1, slot 32, the key would be block root at slot 31)
-	// For simplicity, the node will skip caching of genesis epoch.
-	if e > params.BeaconConfig().GenesisEpoch+params.BeaconConfig().MinSeedLookahead {
+	// For simplicity, the node will skip caching of genesis epoch. If the passed state has not yet reached this slot then we do not check the cache.
+	if e <= stateEpoch && e > params.BeaconConfig().GenesisEpoch+params.BeaconConfig().MinSeedLookahead {
 		s, err := slots.EpochEnd(e - 1)
 		if err != nil {
 			return 0, err

beacon-chain/core/helpers/validators_test.go

@@ -1161,6 +1161,10 @@ func TestValidatorMaxEffectiveBalance(t *testing.T) {
 }
 
 func TestBeaconProposerIndexAtSlotFulu(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	cfg := params.BeaconConfig().Copy()
+	cfg.FuluForkEpoch = 1
+	params.OverrideBeaconConfig(cfg)
 	lookahead := make([]uint64, 64)
 	lookahead[0] = 15
 	lookahead[1] = 16
@@ -1180,8 +1184,4 @@ func TestBeaconProposerIndexAtSlotFulu(t *testing.T) {
 	idx, err = helpers.BeaconProposerIndexAtSlot(t.Context(), st, 130)
 	require.NoError(t, err)
 	require.Equal(t, primitives.ValidatorIndex(42), idx)
-	_, err = helpers.BeaconProposerIndexAtSlot(t.Context(), st, 95)
-	require.ErrorContains(t, "slot 95 is not in the current epoch 3 or the next epoch", err)
-	_, err = helpers.BeaconProposerIndexAtSlot(t.Context(), st, 160)
-	require.ErrorContains(t, "slot 160 is not in the current epoch 3 or the next epoch", err)
 }

beacon-chain/core/light-client/store.go

@@ -1,202 +0,0 @@
-package light_client
-
-import (
-	"context"
-	"sync"
-
-	"github.com/OffchainLabs/prysm/v6/async/event"
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed"
-	statefeed "github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed/state"
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/iface"
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p"
-	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
-	"github.com/pkg/errors"
-	log "github.com/sirupsen/logrus"
-)
-
-var ErrLightClientBootstrapNotFound = errors.New("light client bootstrap not found")
-
-type Store struct {
-	mu sync.RWMutex
-
-	beaconDB             iface.HeadAccessDatabase
-	lastFinalityUpdate   interfaces.LightClientFinalityUpdate   // tracks the best finality update seen so far
-	lastOptimisticUpdate interfaces.LightClientOptimisticUpdate // tracks the best optimistic update seen so far
-	p2p                  p2p.Accessor
-	stateFeed            event.SubscriberSender
-}
-
-func NewLightClientStore(db iface.HeadAccessDatabase, p p2p.Accessor, e event.SubscriberSender) *Store {
-	return &Store{
-		beaconDB:  db,
-		p2p:       p,
-		stateFeed: e,
-	}
-}
-
-func (s *Store) LightClientBootstrap(ctx context.Context, blockRoot [32]byte) (interfaces.LightClientBootstrap, error) {
-	s.mu.RLock()
-	defer s.mu.RUnlock()
-
-	// Fetch the light client bootstrap from the database
-	bootstrap, err := s.beaconDB.LightClientBootstrap(ctx, blockRoot[:])
-	if err != nil {
-		return nil, err
-	}
-	if bootstrap == nil { // not found
-		return nil, ErrLightClientBootstrapNotFound
-	}
-
-	return bootstrap, nil
-}
-
-func (s *Store) SaveLightClientBootstrap(ctx context.Context, blockRoot [32]byte) error {
-	s.mu.Lock()
-	defer s.mu.Unlock()
-
-	blk, err := s.beaconDB.Block(ctx, blockRoot)
-	if err != nil {
-		return errors.Wrapf(err, "failed to fetch block for root %x", blockRoot)
-	}
-	if blk == nil {
-		return errors.Errorf("failed to fetch block for root %x", blockRoot)
-	}
-
-	state, err := s.beaconDB.State(ctx, blockRoot)
-	if err != nil {
-		return errors.Wrapf(err, "failed to fetch state for block root %x", blockRoot)
-	}
-	if state == nil {
-		return errors.Errorf("failed to fetch state for block root %x", blockRoot)
-	}
-
-	bootstrap, err := NewLightClientBootstrapFromBeaconState(ctx, state.Slot(), state, blk)
-	if err != nil {
-		return errors.Wrapf(err, "failed to create light client bootstrap for block root %x", blockRoot)
-	}
-
-	// Save the light client bootstrap to the database
-	if err := s.beaconDB.SaveLightClientBootstrap(ctx, blockRoot[:], bootstrap); err != nil {
-		return err
-	}
-	return nil
-}
-
-func (s *Store) LightClientUpdates(ctx context.Context, startPeriod, endPeriod uint64) ([]interfaces.LightClientUpdate, error) {
-	s.mu.RLock()
-	defer s.mu.RUnlock()
-
-	// Fetch the light client updatesMap from the database
-	updatesMap, err := s.beaconDB.LightClientUpdates(ctx, startPeriod, endPeriod)
-	if err != nil {
-		return nil, err
-	}
-
-	var updates []interfaces.LightClientUpdate
-	for i := startPeriod; i <= endPeriod; i++ {
-		update, ok := updatesMap[i]
-		if !ok {
-			// Only return the first contiguous range of updates
-			break
-		}
-		updates = append(updates, update)
-	}
-
-	return updates, nil
-}
-
-func (s *Store) LightClientUpdate(ctx context.Context, period uint64) (interfaces.LightClientUpdate, error) {
-	s.mu.RLock()
-	defer s.mu.RUnlock()
-
-	// Fetch the light client update for the given period from the database
-	update, err := s.beaconDB.LightClientUpdate(ctx, period)
-	if err != nil {
-		return nil, err
-	}
-
-	return update, nil
-}
-
-func (s *Store) SaveLightClientUpdate(ctx context.Context, period uint64, update interfaces.LightClientUpdate) error {
-	s.mu.Lock()
-	defer s.mu.Unlock()
-
-	oldUpdate, err := s.beaconDB.LightClientUpdate(ctx, period)
-	if err != nil {
-		return errors.Wrapf(err, "could not get current light client update")
-	}
-
-	if oldUpdate == nil {
-		if err := s.beaconDB.SaveLightClientUpdate(ctx, period, update); err != nil {
-			return errors.Wrapf(err, "could not save light client update")
-		}
-		log.WithField("period", period).Debug("Saved new light client update")
-		return nil
-	}
-
-	isNewUpdateBetter, err := IsBetterUpdate(update, oldUpdate)
-	if err != nil {
-		return errors.Wrapf(err, "could not compare light client updates")
-	}
-
-	if isNewUpdateBetter {
-		if err := s.beaconDB.SaveLightClientUpdate(ctx, period, update); err != nil {
-			return errors.Wrapf(err, "could not save light client update")
-		}
-		log.WithField("period", period).Debug("Saved new light client update")
-		return nil
-	}
-	log.WithField("period", period).Debug("New light client update is not better than the current one, skipping save")
-	return nil
-}
-
-func (s *Store) SetLastFinalityUpdate(update interfaces.LightClientFinalityUpdate, broadcast bool) {
-	s.mu.Lock()
-	defer s.mu.Unlock()
-
-	if broadcast && IsFinalityUpdateValidForBroadcast(update, s.lastFinalityUpdate) {
-		if err := s.p2p.BroadcastLightClientFinalityUpdate(context.Background(), update); err != nil {
-			log.WithError(err).Error("Could not broadcast light client finality update")
-		}
-	}
-
-	s.lastFinalityUpdate = update
-	log.Debug("Saved new light client finality update")
-
-	s.stateFeed.Send(&feed.Event{
-		Type: statefeed.LightClientFinalityUpdate,
-		Data: update,
-	})
-}
-
-func (s *Store) LastFinalityUpdate() interfaces.LightClientFinalityUpdate {
-	s.mu.RLock()
-	defer s.mu.RUnlock()
-	return s.lastFinalityUpdate
-}
-
-func (s *Store) SetLastOptimisticUpdate(update interfaces.LightClientOptimisticUpdate, broadcast bool) {
-	s.mu.Lock()
-	defer s.mu.Unlock()
-
-	if broadcast {
-		if err := s.p2p.BroadcastLightClientOptimisticUpdate(context.Background(), update); err != nil {
-			log.WithError(err).Error("Could not broadcast light client optimistic update")
-		}
-	}
-
-	s.lastOptimisticUpdate = update
-	log.Debug("Saved new light client optimistic update")
-
-	s.stateFeed.Send(&feed.Event{
-		Type: statefeed.LightClientOptimisticUpdate,
-		Data: update,
-	})
-}
-
-func (s *Store) LastOptimisticUpdate() interfaces.LightClientOptimisticUpdate {
-	s.mu.RLock()
-	defer s.mu.RUnlock()
-	return s.lastOptimisticUpdate
-}

beacon-chain/core/light-client/store_test.go

@@ -1,165 +0,0 @@
-package light_client_test
-
-import (
-	"testing"
-
-	"github.com/OffchainLabs/prysm/v6/async/event"
-	lightClient "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client"
-	testDB "github.com/OffchainLabs/prysm/v6/beacon-chain/db/testing"
-	p2pTesting "github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/testing"
-	"github.com/OffchainLabs/prysm/v6/config/params"
-	"github.com/OffchainLabs/prysm/v6/runtime/version"
-	"github.com/OffchainLabs/prysm/v6/testing/require"
-	"github.com/OffchainLabs/prysm/v6/testing/util"
-)
-
-func TestLightClientStore(t *testing.T) {
-	params.SetupTestConfigCleanup(t)
-	cfg := params.BeaconConfig()
-	cfg.AltairForkEpoch = 1
-	cfg.BellatrixForkEpoch = 2
-	cfg.CapellaForkEpoch = 3
-	cfg.DenebForkEpoch = 4
-	cfg.ElectraForkEpoch = 5
-	params.OverrideBeaconConfig(cfg)
-
-	// Initialize the light client store
-	lcStore := lightClient.NewLightClientStore(testDB.SetupDB(t), &p2pTesting.FakeP2P{}, new(event.Feed))
-
-	// Create test light client updates for Capella and Deneb
-	lCapella := util.NewTestLightClient(t, version.Capella)
-	opUpdateCapella, err := lightClient.NewLightClientOptimisticUpdateFromBeaconState(lCapella.Ctx, lCapella.State, lCapella.Block, lCapella.AttestedState, lCapella.AttestedBlock)
-	require.NoError(t, err)
-	require.NotNil(t, opUpdateCapella, "OptimisticUpdateCapella is nil")
-	finUpdateCapella, err := lightClient.NewLightClientFinalityUpdateFromBeaconState(lCapella.Ctx, lCapella.State, lCapella.Block, lCapella.AttestedState, lCapella.AttestedBlock, lCapella.FinalizedBlock)
-	require.NoError(t, err)
-	require.NotNil(t, finUpdateCapella, "FinalityUpdateCapella is nil")
-
-	lDeneb := util.NewTestLightClient(t, version.Deneb)
-	opUpdateDeneb, err := lightClient.NewLightClientOptimisticUpdateFromBeaconState(lDeneb.Ctx, lDeneb.State, lDeneb.Block, lDeneb.AttestedState, lDeneb.AttestedBlock)
-	require.NoError(t, err)
-	require.NotNil(t, opUpdateDeneb, "OptimisticUpdateDeneb is nil")
-	finUpdateDeneb, err := lightClient.NewLightClientFinalityUpdateFromBeaconState(lDeneb.Ctx, lDeneb.State, lDeneb.Block, lDeneb.AttestedState, lDeneb.AttestedBlock, lDeneb.FinalizedBlock)
-	require.NoError(t, err)
-	require.NotNil(t, finUpdateDeneb, "FinalityUpdateDeneb is nil")
-
-	// Initially the store should have nil values for both updates
-	require.IsNil(t, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should be nil")
-	require.IsNil(t, lcStore.LastOptimisticUpdate(), "lastOptimisticUpdate should be nil")
-
-	// Set and get finality with Capella update. Optimistic update should be nil
-	lcStore.SetLastFinalityUpdate(finUpdateCapella, false)
-	require.Equal(t, finUpdateCapella, lcStore.LastFinalityUpdate(), "lastFinalityUpdate is wrong")
-	require.IsNil(t, lcStore.LastOptimisticUpdate(), "lastOptimisticUpdate should be nil")
-
-	// Set and get optimistic with Capella update. Finality update should be Capella
-	lcStore.SetLastOptimisticUpdate(opUpdateCapella, false)
-	require.Equal(t, opUpdateCapella, lcStore.LastOptimisticUpdate(), "lastOptimisticUpdate is wrong")
-	require.Equal(t, finUpdateCapella, lcStore.LastFinalityUpdate(), "lastFinalityUpdate is wrong")
-
-	// Set and get finality and optimistic with Deneb update
-	lcStore.SetLastFinalityUpdate(finUpdateDeneb, false)
-	lcStore.SetLastOptimisticUpdate(opUpdateDeneb, false)
-	require.Equal(t, finUpdateDeneb, lcStore.LastFinalityUpdate(), "lastFinalityUpdate is wrong")
-	require.Equal(t, opUpdateDeneb, lcStore.LastOptimisticUpdate(), "lastOptimisticUpdate is wrong")
-}
-
-func TestLightClientStore_SetLastFinalityUpdate(t *testing.T) {
-	p2p := p2pTesting.NewTestP2P(t)
-	lcStore := lightClient.NewLightClientStore(testDB.SetupDB(t), p2p, new(event.Feed))
-
-	// update 0 with basic data and no supermajority following an empty lastFinalityUpdate - should save and broadcast
-	l0 := util.NewTestLightClient(t, version.Altair)
-	update0, err := lightClient.NewLightClientFinalityUpdateFromBeaconState(l0.Ctx, l0.State, l0.Block, l0.AttestedState, l0.AttestedBlock, l0.FinalizedBlock)
-	require.NoError(t, err, "Failed to create light client finality update")
-
-	require.Equal(t, true, lightClient.IsBetterFinalityUpdate(update0, lcStore.LastFinalityUpdate()), "update0 should be better than nil")
-	// update0 should be valid for broadcast - meaning it should be broadcasted
-	require.Equal(t, true, lightClient.IsFinalityUpdateValidForBroadcast(update0, lcStore.LastFinalityUpdate()), "update0 should be valid for broadcast")
-
-	lcStore.SetLastFinalityUpdate(update0, true)
-	require.Equal(t, update0, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should match the set value")
-	require.Equal(t, true, p2p.BroadcastCalled.Load(), "Broadcast should have been called after setting a new last finality update when previous is nil")
-	p2p.BroadcastCalled.Store(false) // Reset for next test
-
-	// update 1 with same finality slot, increased attested slot, and no supermajority - should save but not broadcast
-	l1 := util.NewTestLightClient(t, version.Altair, util.WithIncreasedAttestedSlot(1))
-	update1, err := lightClient.NewLightClientFinalityUpdateFromBeaconState(l1.Ctx, l1.State, l1.Block, l1.AttestedState, l1.AttestedBlock, l1.FinalizedBlock)
-	require.NoError(t, err, "Failed to create light client finality update")
-
-	require.Equal(t, true, lightClient.IsBetterFinalityUpdate(update1, update0), "update1 should be better than update0")
-	// update1 should not be valid for broadcast - meaning it should not be broadcasted
-	require.Equal(t, false, lightClient.IsFinalityUpdateValidForBroadcast(update1, lcStore.LastFinalityUpdate()), "update1 should not be valid for broadcast")
-
-	lcStore.SetLastFinalityUpdate(update1, true)
-	require.Equal(t, update1, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should match the set value")
-	require.Equal(t, false, p2p.BroadcastCalled.Load(), "Broadcast should not have been called after setting a new last finality update without supermajority")
-	p2p.BroadcastCalled.Store(false) // Reset for next test
-
-	// update 2 with same finality slot, increased attested slot, and supermajority - should save and broadcast
-	l2 := util.NewTestLightClient(t, version.Altair, util.WithIncreasedAttestedSlot(2), util.WithSupermajority())
-	update2, err := lightClient.NewLightClientFinalityUpdateFromBeaconState(l2.Ctx, l2.State, l2.Block, l2.AttestedState, l2.AttestedBlock, l2.FinalizedBlock)
-	require.NoError(t, err, "Failed to create light client finality update")
-
-	require.Equal(t, true, lightClient.IsBetterFinalityUpdate(update2, update1), "update2 should be better than update1")
-	// update2 should be valid for broadcast - meaning it should be broadcasted
-	require.Equal(t, true, lightClient.IsFinalityUpdateValidForBroadcast(update2, lcStore.LastFinalityUpdate()), "update2 should be valid for broadcast")
-
-	lcStore.SetLastFinalityUpdate(update2, true)
-	require.Equal(t, update2, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should match the set value")
-	require.Equal(t, true, p2p.BroadcastCalled.Load(), "Broadcast should have been called after setting a new last finality update with supermajority")
-	p2p.BroadcastCalled.Store(false) // Reset for next test
-
-	// update 3 with same finality slot, increased attested slot, and supermajority - should save but not broadcast
-	l3 := util.NewTestLightClient(t, version.Altair, util.WithIncreasedAttestedSlot(3), util.WithSupermajority())
-	update3, err := lightClient.NewLightClientFinalityUpdateFromBeaconState(l3.Ctx, l3.State, l3.Block, l3.AttestedState, l3.AttestedBlock, l3.FinalizedBlock)
-	require.NoError(t, err, "Failed to create light client finality update")
-
-	require.Equal(t, true, lightClient.IsBetterFinalityUpdate(update3, update2), "update3 should be better than update2")
-	// update3 should not be valid for broadcast - meaning it should not be broadcasted
-	require.Equal(t, false, lightClient.IsFinalityUpdateValidForBroadcast(update3, lcStore.LastFinalityUpdate()), "update3 should not be valid for broadcast")
-
-	lcStore.SetLastFinalityUpdate(update3, true)
-	require.Equal(t, update3, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should match the set value")
-	require.Equal(t, false, p2p.BroadcastCalled.Load(), "Broadcast should not have been when previous was already broadcast")
-
-	// update 4 with increased finality slot, increased attested slot, and supermajority - should save and broadcast
-	l4 := util.NewTestLightClient(t, version.Altair, util.WithIncreasedFinalizedSlot(1), util.WithIncreasedAttestedSlot(1), util.WithSupermajority())
-	update4, err := lightClient.NewLightClientFinalityUpdateFromBeaconState(l4.Ctx, l4.State, l4.Block, l4.AttestedState, l4.AttestedBlock, l4.FinalizedBlock)
-	require.NoError(t, err, "Failed to create light client finality update")
-
-	require.Equal(t, true, lightClient.IsBetterFinalityUpdate(update4, update3), "update4 should be better than update3")
-	// update4 should be valid for broadcast - meaning it should be broadcasted
-	require.Equal(t, true, lightClient.IsFinalityUpdateValidForBroadcast(update4, lcStore.LastFinalityUpdate()), "update4 should be valid for broadcast")
-
-	lcStore.SetLastFinalityUpdate(update4, true)
-	require.Equal(t, update4, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should match the set value")
-	require.Equal(t, true, p2p.BroadcastCalled.Load(), "Broadcast should have been called after a new finality update with increased finality slot")
-	p2p.BroadcastCalled.Store(false) // Reset for next test
-
-	// update 5 with the same new finality slot, increased attested slot, and supermajority - should save but not broadcast
-	l5 := util.NewTestLightClient(t, version.Altair, util.WithIncreasedFinalizedSlot(1), util.WithIncreasedAttestedSlot(2), util.WithSupermajority())
-	update5, err := lightClient.NewLightClientFinalityUpdateFromBeaconState(l5.Ctx, l5.State, l5.Block, l5.AttestedState, l5.AttestedBlock, l5.FinalizedBlock)
-	require.NoError(t, err, "Failed to create light client finality update")
-
-	require.Equal(t, true, lightClient.IsBetterFinalityUpdate(update5, update4), "update5 should be better than update4")
-	// update5 should not be valid for broadcast - meaning it should not be broadcasted
-	require.Equal(t, false, lightClient.IsFinalityUpdateValidForBroadcast(update5, lcStore.LastFinalityUpdate()), "update5 should not be valid for broadcast")
-
-	lcStore.SetLastFinalityUpdate(update5, true)
-	require.Equal(t, update5, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should match the set value")
-	require.Equal(t, false, p2p.BroadcastCalled.Load(), "Broadcast should not have been called when previous was already broadcast with supermajority")
-
-	// update 6 with the same new finality slot, increased attested slot, and no supermajority - should save but not broadcast
-	l6 := util.NewTestLightClient(t, version.Altair, util.WithIncreasedFinalizedSlot(1), util.WithIncreasedAttestedSlot(3))
-	update6, err := lightClient.NewLightClientFinalityUpdateFromBeaconState(l6.Ctx, l6.State, l6.Block, l6.AttestedState, l6.AttestedBlock, l6.FinalizedBlock)
-	require.NoError(t, err, "Failed to create light client finality update")
-
-	require.Equal(t, true, lightClient.IsBetterFinalityUpdate(update6, update5), "update6 should be better than update5")
-	// update6 should not be valid for broadcast - meaning it should not be broadcasted
-	require.Equal(t, false, lightClient.IsFinalityUpdateValidForBroadcast(update6, lcStore.LastFinalityUpdate()), "update6 should not be valid for broadcast")
-
-	lcStore.SetLastFinalityUpdate(update6, true)
-	require.Equal(t, update6, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should match the set value")
-	require.Equal(t, false, p2p.BroadcastCalled.Load(), "Broadcast should not have been called when previous was already broadcast with supermajority")
-}

beacon-chain/core/peerdas/BUILD.bazel

@@ -19,11 +19,11 @@ go_library(
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
         "//consensus-types/blocks:go_default_library",
-        "//consensus-types/interfaces:go_default_library",
         "//consensus-types/primitives:go_default_library",
         "//container/trie:go_default_library",
         "//crypto/hash:go_default_library",
         "//encoding/bytesutil:go_default_library",
+        "//proto/engine/v1:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
         "//runtime/version:go_default_library",
         "@com_github_ethereum_go_ethereum//p2p/enode:go_default_library",

beacon-chain/core/peerdas/das_core.go

@@ -4,15 +4,10 @@ import (
 	"encoding/binary"
 	"math"
 	"slices"
-	"time"
 
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/kzg"
 	"github.com/OffchainLabs/prysm/v6/config/params"
-	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
-	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
 	"github.com/OffchainLabs/prysm/v6/crypto/hash"
 	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
-	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/ethereum/go-ethereum/p2p/enode"
 	"github.com/holiman/uint256"
 	"github.com/pkg/errors"
@@ -20,12 +15,9 @@ import (
 
 var (
 	// Custom errors
-	ErrCustodyGroupTooLarge               = errors.New("custody group too large")
-	ErrCustodyGroupCountTooLarge          = errors.New("custody group count too large")
-	ErrSizeMismatch                       = errors.New("mismatch in the number of blob KZG commitments and cellsAndProofs")
-	ErrNotEnoughDataColumnSidecars        = errors.New("not enough columns")
-	ErrDataColumnSidecarsNotSortedByIndex = errors.New("data column sidecars are not sorted by index")
-	errWrongComputedCustodyGroupCount     = errors.New("wrong computed custody group count, should never happen")
+	ErrCustodyGroupTooLarge           = errors.New("custody group too large")
+	ErrCustodyGroupCountTooLarge      = errors.New("custody group count too large")
+	errWrongComputedCustodyGroupCount = errors.New("wrong computed custody group count, should never happen")
 
 	// maxUint256 is the maximum value of an uint256.
 	maxUint256 = &uint256.Int{math.MaxUint64, math.MaxUint64, math.MaxUint64, math.MaxUint64}
@@ -117,44 +109,6 @@ func ComputeColumnsForCustodyGroup(custodyGroup uint64) ([]uint64, error) {
 	return columns, nil
 }
 
-// DataColumnSidecars computes the data column sidecars from the signed block, cells and cell proofs.
-// The returned value contains pointers to function parameters.
-// (If the caller alterates `cellsAndProofs` afterwards, the returned value will be modified as well.)
-// https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/validator.md#get_data_column_sidecars_from_block
-func DataColumnSidecars(signedBlock interfaces.ReadOnlySignedBeaconBlock, cellsAndProofs []kzg.CellsAndProofs) ([]*ethpb.DataColumnSidecar, error) {
-	if signedBlock == nil || signedBlock.IsNil() || len(cellsAndProofs) == 0 {
-		return nil, nil
-	}
-
-	block := signedBlock.Block()
-	blockBody := block.Body()
-	blobKzgCommitments, err := blockBody.BlobKzgCommitments()
-	if err != nil {
-		return nil, errors.Wrap(err, "blob KZG commitments")
-	}
-
-	if len(blobKzgCommitments) != len(cellsAndProofs) {
-		return nil, ErrSizeMismatch
-	}
-
-	signedBlockHeader, err := signedBlock.Header()
-	if err != nil {
-		return nil, errors.Wrap(err, "signed block header")
-	}
-
-	kzgCommitmentsInclusionProof, err := blocks.MerkleProofKZGCommitments(blockBody)
-	if err != nil {
-		return nil, errors.Wrap(err, "merkle proof KZG commitments")
-	}
-
-	dataColumnSidecars, err := dataColumnsSidecars(signedBlockHeader, blobKzgCommitments, kzgCommitmentsInclusionProof, cellsAndProofs)
-	if err != nil {
-		return nil, errors.Wrap(err, "data column sidecars")
-	}
-
-	return dataColumnSidecars, nil
-}
-
 // ComputeCustodyGroupForColumn computes the custody group for a given column.
 // It is the reciprocal function of ComputeColumnsForCustodyGroup.
 func ComputeCustodyGroupForColumn(columnIndex uint64) (uint64, error) {
@@ -194,72 +148,3 @@ func CustodyColumns(custodyGroups []uint64) (map[uint64]bool, error) {
 
 	return columns, nil
 }
-
-// dataColumnsSidecars computes the data column sidecars from the signed block header, the blob KZG commiments,
-// the KZG commitment includion proofs and cells and cell proofs.
-// The returned value contains pointers to function parameters.
-// (If the caller alterates input parameters afterwards, the returned value will be modified as well.)
-// https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/validator.md#get_data_column_sidecars
-func dataColumnsSidecars(
-	signedBlockHeader *ethpb.SignedBeaconBlockHeader,
-	blobKzgCommitments [][]byte,
-	kzgCommitmentsInclusionProof [][]byte,
-	cellsAndProofs []kzg.CellsAndProofs,
-) ([]*ethpb.DataColumnSidecar, error) {
-	start := time.Now()
-	if len(blobKzgCommitments) != len(cellsAndProofs) {
-		return nil, ErrSizeMismatch
-	}
-
-	numberOfColumns := params.BeaconConfig().NumberOfColumns
-
-	blobsCount := len(cellsAndProofs)
-	sidecars := make([]*ethpb.DataColumnSidecar, 0, numberOfColumns)
-	for columnIndex := range numberOfColumns {
-		column := make([]kzg.Cell, 0, blobsCount)
-		kzgProofOfColumn := make([]kzg.Proof, 0, blobsCount)
-
-		for rowIndex := range blobsCount {
-			cellsForRow := cellsAndProofs[rowIndex].Cells
-			proofsForRow := cellsAndProofs[rowIndex].Proofs
-
-			// Validate that we have enough cells and proofs for this column index
-			if columnIndex >= uint64(len(cellsForRow)) {
-				return nil, errors.Errorf("column index %d exceeds cells length %d for blob %d", columnIndex, len(cellsForRow), rowIndex)
-			}
-			if columnIndex >= uint64(len(proofsForRow)) {
-				return nil, errors.Errorf("column index %d exceeds proofs length %d for blob %d", columnIndex, len(proofsForRow), rowIndex)
-			}
-
-			cell := cellsForRow[columnIndex]
-			column = append(column, cell)
-
-			kzgProof := proofsForRow[columnIndex]
-			kzgProofOfColumn = append(kzgProofOfColumn, kzgProof)
-		}
-
-		columnBytes := make([][]byte, 0, blobsCount)
-		for i := range column {
-			columnBytes = append(columnBytes, column[i][:])
-		}
-
-		kzgProofOfColumnBytes := make([][]byte, 0, blobsCount)
-		for _, kzgProof := range kzgProofOfColumn {
-			kzgProofOfColumnBytes = append(kzgProofOfColumnBytes, kzgProof[:])
-		}
-
-		sidecar := &ethpb.DataColumnSidecar{
-			Index:                        columnIndex,
-			Column:                       columnBytes,
-			KzgCommitments:               blobKzgCommitments,
-			KzgProofs:                    kzgProofOfColumnBytes,
-			SignedBlockHeader:            signedBlockHeader,
-			KzgCommitmentsInclusionProof: kzgCommitmentsInclusionProof,
-		}
-
-		sidecars = append(sidecars, sidecar)
-	}
-
-	dataColumnComputationTime.Observe(float64(time.Since(start).Milliseconds()))
-	return sidecars, nil
-}

beacon-chain/core/peerdas/das_core_test.go

@@ -3,13 +3,9 @@ package peerdas_test
 import (
 	"testing"
 
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/kzg"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
 	"github.com/OffchainLabs/prysm/v6/config/params"
-	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
-	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v6/testing/require"
-	"github.com/OffchainLabs/prysm/v6/testing/util"
 	"github.com/ethereum/go-ethereum/p2p/enode"
 )
 
@@ -31,93 +27,6 @@ func TestComputeColumnsForCustodyGroup(t *testing.T) {
 	require.ErrorIs(t, err, peerdas.ErrCustodyGroupTooLarge)
 }
 
-func TestDataColumnSidecars(t *testing.T) {
-	t.Run("nil signed block", func(t *testing.T) {
-		var expected []*ethpb.DataColumnSidecar = nil
-		actual, err := peerdas.DataColumnSidecars(nil, []kzg.CellsAndProofs{})
-		require.NoError(t, err)
-
-		require.DeepSSZEqual(t, expected, actual)
-	})
-
-	t.Run("empty cells and proofs", func(t *testing.T) {
-		// Create a protobuf signed beacon block.
-		signedBeaconBlockPb := util.NewBeaconBlockDeneb()
-
-		// Create a signed beacon block from the protobuf.
-		signedBeaconBlock, err := blocks.NewSignedBeaconBlock(signedBeaconBlockPb)
-		require.NoError(t, err)
-
-		actual, err := peerdas.DataColumnSidecars(signedBeaconBlock, []kzg.CellsAndProofs{})
-		require.NoError(t, err)
-		require.IsNil(t, actual)
-	})
-
-	t.Run("sizes mismatch", func(t *testing.T) {
-		// Create a protobuf signed beacon block.
-		signedBeaconBlockPb := util.NewBeaconBlockDeneb()
-
-		// Create a signed beacon block from the protobuf.
-		signedBeaconBlock, err := blocks.NewSignedBeaconBlock(signedBeaconBlockPb)
-		require.NoError(t, err)
-
-		// Create cells and proofs.
-		cellsAndProofs := make([]kzg.CellsAndProofs, 1)
-
-		_, err = peerdas.DataColumnSidecars(signedBeaconBlock, cellsAndProofs)
-		require.ErrorIs(t, err, peerdas.ErrSizeMismatch)
-	})
-
-	t.Run("cells array too short for column index", func(t *testing.T) {
-		// Create a Fulu block with a blob commitment.
-		signedBeaconBlockPb := util.NewBeaconBlockFulu()
-		signedBeaconBlockPb.Block.Body.BlobKzgCommitments = [][]byte{make([]byte, 48)}
-
-		// Create a signed beacon block from the protobuf.
-		signedBeaconBlock, err := blocks.NewSignedBeaconBlock(signedBeaconBlockPb)
-		require.NoError(t, err)
-
-		// Create cells and proofs with insufficient cells for the number of columns.
-		// This simulates a scenario where cellsAndProofs has fewer cells than expected columns.
-		cellsAndProofs := []kzg.CellsAndProofs{
-			{
-				Cells:  make([]kzg.Cell, 10),  // Only 10 cells
-				Proofs: make([]kzg.Proof, 10), // Only 10 proofs
-			},
-		}
-
-		// This should fail because the function will try to access columns up to NumberOfColumns
-		// but we only have 10 cells/proofs.
-		_, err = peerdas.DataColumnSidecars(signedBeaconBlock, cellsAndProofs)
-		require.ErrorContains(t, "column index", err)
-		require.ErrorContains(t, "exceeds cells length", err)
-	})
-
-	t.Run("proofs array too short for column index", func(t *testing.T) {
-		// Create a Fulu block with a blob commitment.
-		signedBeaconBlockPb := util.NewBeaconBlockFulu()
-		signedBeaconBlockPb.Block.Body.BlobKzgCommitments = [][]byte{make([]byte, 48)}
-
-		// Create a signed beacon block from the protobuf.
-		signedBeaconBlock, err := blocks.NewSignedBeaconBlock(signedBeaconBlockPb)
-		require.NoError(t, err)
-
-		// Create cells and proofs with sufficient cells but insufficient proofs.
-		numberOfColumns := params.BeaconConfig().NumberOfColumns
-		cellsAndProofs := []kzg.CellsAndProofs{
-			{
-				Cells:  make([]kzg.Cell, numberOfColumns),
-				Proofs: make([]kzg.Proof, 5), // Only 5 proofs, less than columns
-			},
-		}
-
-		// This should fail when trying to access proof beyond index 4.
-		_, err = peerdas.DataColumnSidecars(signedBeaconBlock, cellsAndProofs)
-		require.ErrorContains(t, "column index", err)
-		require.ErrorContains(t, "exceeds proofs length", err)
-	})
-}
-
 func TestComputeCustodyGroupForColumn(t *testing.T) {
 	params.SetupTestConfigCleanup(t)
 	config := params.BeaconConfig()

beacon-chain/core/peerdas/p2p_interface_test.go

@@ -63,17 +63,14 @@ func TestVerifyDataColumnSidecarKZGProofs(t *testing.T) {
 	t.Run("invalid proof", func(t *testing.T) {
 		sidecars := generateRandomSidecars(t, seed, blobCount)
 		sidecars[0].Column[0][0]++ // It is OK to overflow
-		roDataColumnSidecars := generateRODataColumnSidecars(t, sidecars)
 
-		err := peerdas.VerifyDataColumnsSidecarKZGProofs(roDataColumnSidecars)
+		err := peerdas.VerifyDataColumnsSidecarKZGProofs(sidecars)
 		require.ErrorIs(t, err, peerdas.ErrInvalidKZGProof)
 	})
 
 	t.Run("nominal", func(t *testing.T) {
 		sidecars := generateRandomSidecars(t, seed, blobCount)
-		roDataColumnSidecars := generateRODataColumnSidecars(t, sidecars)
-
-		err := peerdas.VerifyDataColumnsSidecarKZGProofs(roDataColumnSidecars)
+		err := peerdas.VerifyDataColumnsSidecarKZGProofs(sidecars)
 		require.NoError(t, err)
 	})
 }
@@ -256,9 +253,8 @@ func BenchmarkVerifyDataColumnSidecarKZGProofs_SameCommitments_NoBatch(b *testin
 	for i := range int64(b.N) {
 		// Generate new random sidecars to ensure the KZG backend does not cache anything.
 		sidecars := generateRandomSidecars(b, i, blobCount)
-		roDataColumnSidecars := generateRODataColumnSidecars(b, sidecars)
 
-		for _, sidecar := range roDataColumnSidecars {
+		for _, sidecar := range sidecars {
 			sidecars := []blocks.RODataColumn{sidecar}
 			b.StartTimer()
 			err := peerdas.VerifyDataColumnsSidecarKZGProofs(sidecars)
@@ -282,7 +278,7 @@ func BenchmarkVerifyDataColumnSidecarKZGProofs_DiffCommitments_Batch(b *testing.
 			b.ResetTimer()
 
 			for j := range int64(b.N) {
-				allSidecars := make([]*ethpb.DataColumnSidecar, 0, numberOfColumns)
+				allSidecars := make([]blocks.RODataColumn, 0, numberOfColumns)
 				for k := int64(0); k < numberOfColumns; k += columnsCount {
 					// Use different seeds to generate different blobs/commitments
 					seed := int64(b.N*i) + numberOfColumns*j + blobCount*k
@@ -292,10 +288,8 @@ func BenchmarkVerifyDataColumnSidecarKZGProofs_DiffCommitments_Batch(b *testing.
 					allSidecars = append(allSidecars, sidecars[k:k+columnsCount]...)
 				}
 
-				roDataColumnSidecars := generateRODataColumnSidecars(b, allSidecars)
-
 				b.StartTimer()
-				err := peerdas.VerifyDataColumnsSidecarKZGProofs(roDataColumnSidecars)
+				err := peerdas.VerifyDataColumnsSidecarKZGProofs(allSidecars)
 				b.StopTimer()
 				require.NoError(b, err)
 			}
@@ -323,8 +317,7 @@ func BenchmarkVerifyDataColumnSidecarKZGProofs_DiffCommitments_Batch4(b *testing
 		for j := range int64(batchCount) {
 			// Use different seeds to generate different blobs/commitments
 			sidecars := generateRandomSidecars(b, int64(batchCount)*i+j*blobCount, blobCount)
-			roDataColumnSidecars := generateRODataColumnSidecars(b, sidecars[:columnsCount])
-			allSidecars = append(allSidecars, roDataColumnSidecars)
+			allSidecars = append(allSidecars, sidecars)
 		}
 
 		for _, sidecars := range allSidecars {
@@ -358,7 +351,7 @@ func createTestSidecar(t *testing.T, index uint64, column, kzgCommitments, kzgPr
 	return roSidecar
 }
 
-func generateRandomSidecars(t testing.TB, seed, blobCount int64) []*ethpb.DataColumnSidecar {
+func generateRandomSidecars(t testing.TB, seed, blobCount int64) []blocks.RODataColumn {
 	dbBlock := util.NewBeaconBlockDeneb()
 
 	commitments := make([][]byte, 0, blobCount)
@@ -379,20 +372,10 @@ func generateRandomSidecars(t testing.TB, seed, blobCount int64) []*ethpb.DataCo
 	require.NoError(t, err)
 
 	cellsAndProofs := util.GenerateCellsAndProofs(t, blobs)
-	sidecars, err := peerdas.DataColumnSidecars(sBlock, cellsAndProofs)
+	rob, err := blocks.NewROBlock(sBlock)
+	require.NoError(t, err)
+	sidecars, err := peerdas.DataColumnSidecars(cellsAndProofs, peerdas.PopulateFromBlock(rob))
 	require.NoError(t, err)
 
 	return sidecars
 }
-
-func generateRODataColumnSidecars(t testing.TB, sidecars []*ethpb.DataColumnSidecar) []blocks.RODataColumn {
-	roDataColumnSidecars := make([]blocks.RODataColumn, 0, len(sidecars))
-	for _, sidecar := range sidecars {
-		roCol, err := blocks.NewRODataColumn(sidecar)
-		require.NoError(t, err)
-
-		roDataColumnSidecars = append(roDataColumnSidecars, roCol)
-	}
-
-	return roDataColumnSidecars
-}

beacon-chain/core/peerdas/reconstruction.go

@@ -5,7 +5,7 @@ import (
 	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
-	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
+	pb "github.com/OffchainLabs/prysm/v6/proto/engine/v1"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/pkg/errors"
 	"golang.org/x/sync/errgroup"
@@ -16,6 +16,7 @@ var (
 	ErrBlobIndexTooHigh         = errors.New("blob index is too high")
 	ErrBlockRootMismatch        = errors.New("block root mismatch")
 	ErrBlobsCellsProofsMismatch = errors.New("blobs and cells proofs mismatch")
+	ErrNilBlobAndProof          = errors.New("nil blob and proof")
 )
 
 // MinimumColumnCountToReconstruct return the minimum number of columns needed to proceed to a reconstruction.
@@ -28,19 +29,19 @@ func MinimumColumnCountToReconstruct() uint64 {
 // ReconstructDataColumnSidecars reconstructs all the data column sidecars from the given input data column sidecars.
 // All input sidecars must be committed to the same block.
 // `inVerifiedRoSidecars` should contain enough (unique) sidecars to reconstruct the missing columns.
-func ReconstructDataColumnSidecars(inVerifiedRoSidecars []blocks.VerifiedRODataColumn) ([]blocks.VerifiedRODataColumn, error) {
+func ReconstructDataColumnSidecars(verifiedRoSidecars []blocks.VerifiedRODataColumn) ([]blocks.VerifiedRODataColumn, error) {
 	// Check if there is at least one input sidecar.
-	if len(inVerifiedRoSidecars) == 0 {
+	if len(verifiedRoSidecars) == 0 {
 		return nil, ErrNotEnoughDataColumnSidecars
 	}
 
 	// Safely retrieve the first sidecar as a reference.
-	referenceSidecar := inVerifiedRoSidecars[0]
+	referenceSidecar := verifiedRoSidecars[0]
 
 	// Check if all columns have the same length and are commmitted to the same block.
 	blobCount := len(referenceSidecar.Column)
 	blockRoot := referenceSidecar.BlockRoot()
-	for _, sidecar := range inVerifiedRoSidecars[1:] {
+	for _, sidecar := range verifiedRoSidecars[1:] {
 		if len(sidecar.Column) != blobCount {
 			return nil, ErrColumnLengthsDiffer
 		}
@@ -51,8 +52,8 @@ func ReconstructDataColumnSidecars(inVerifiedRoSidecars []blocks.VerifiedRODataC
 	}
 
 	// Deduplicate sidecars.
-	sidecarByIndex := make(map[uint64]blocks.VerifiedRODataColumn, len(inVerifiedRoSidecars))
-	for _, inVerifiedRoSidecar := range inVerifiedRoSidecars {
+	sidecarByIndex := make(map[uint64]blocks.VerifiedRODataColumn, len(verifiedRoSidecars))
+	for _, inVerifiedRoSidecar := range verifiedRoSidecars {
 		sidecarByIndex[inVerifiedRoSidecar.Index] = inVerifiedRoSidecar
 	}
 
@@ -62,12 +63,6 @@ func ReconstructDataColumnSidecars(inVerifiedRoSidecars []blocks.VerifiedRODataC
 		return nil, ErrNotEnoughDataColumnSidecars
 	}
 
-	// Sidecars are verified and are committed to the same block.
-	// All signed block headers, KZG commitments, and inclusion proofs are the same.
-	signedBlockHeader := referenceSidecar.SignedBlockHeader
-	kzgCommitments := referenceSidecar.KzgCommitments
-	kzgCommitmentsInclusionProof := referenceSidecar.KzgCommitmentsInclusionProof
-
 	// Recover cells and compute proofs in parallel.
 	var wg errgroup.Group
 	cellsAndProofs := make([]kzg.CellsAndProofs, blobCount)
@@ -100,78 +95,20 @@ func ReconstructDataColumnSidecars(inVerifiedRoSidecars []blocks.VerifiedRODataC
 		return nil, errors.Wrap(err, "wait for RecoverCellsAndKZGProofs")
 	}
 
-	outSidecars, err := dataColumnsSidecars(signedBlockHeader, kzgCommitments, kzgCommitmentsInclusionProof, cellsAndProofs)
+	outSidecars, err := DataColumnSidecars(cellsAndProofs, PopulateFromSidecar(referenceSidecar))
 	if err != nil {
 		return nil, errors.Wrap(err, "data column sidecars from items")
 	}
 
 	// Input sidecars are verified, and we reconstructed ourselves the missing sidecars.
 	// As a consequence, reconstructed sidecars are also verified.
-	outVerifiedRoSidecars := make([]blocks.VerifiedRODataColumn, 0, len(outSidecars))
+	reconstructedVerifiedRoSidecars := make([]blocks.VerifiedRODataColumn, 0, len(outSidecars))
 	for _, sidecar := range outSidecars {
-		roSidecar, err := blocks.NewRODataColumnWithRoot(sidecar, blockRoot)
-		if err != nil {
-			return nil, errors.Wrap(err, "new RO data column with root")
-		}
-
-		verifiedRoSidecar := blocks.NewVerifiedRODataColumn(roSidecar)
-		outVerifiedRoSidecars = append(outVerifiedRoSidecars, verifiedRoSidecar)
+		verifiedRoSidecar := blocks.NewVerifiedRODataColumn(sidecar)
+		reconstructedVerifiedRoSidecars = append(reconstructedVerifiedRoSidecars, verifiedRoSidecar)
 	}
 
-	return outVerifiedRoSidecars, nil
-}
-
-// ConstructDataColumnSidecars constructs data column sidecars from a block, (un-extended) blobs and
-// cell proofs corresponding the extended blobs. The main purpose of this function is to
-// construct data column sidecars from data obtained from the execution client via:
-// - `engine_getBlobsV2` - https://github.com/ethereum/execution-apis/blob/main/src/engine/osaka.md#engine_getblobsv2, or
-// - `engine_getPayloadV5` - https://github.com/ethereum/execution-apis/blob/main/src/engine/osaka.md#engine_getpayloadv5
-// Note: In this function, to stick with the `BlobsBundleV2` format returned by the execution client in `engine_getPayloadV5`,
-// cell proofs are "flattened".
-func ConstructDataColumnSidecars(block interfaces.ReadOnlySignedBeaconBlock, blobs [][]byte, cellProofs [][]byte) ([]*ethpb.DataColumnSidecar, error) {
-	// Check if the cells count is equal to the cell proofs count.
-	numberOfColumns := params.BeaconConfig().NumberOfColumns
-	blobCount := uint64(len(blobs))
-	cellProofsCount := uint64(len(cellProofs))
-
-	cellsCount := blobCount * numberOfColumns
-	if cellsCount != cellProofsCount {
-		return nil, ErrBlobsCellsProofsMismatch
-	}
-
-	cellsAndProofs := make([]kzg.CellsAndProofs, 0, blobCount)
-	for i, blob := range blobs {
-		var kzgBlob kzg.Blob
-		if copy(kzgBlob[:], blob) != len(kzgBlob) {
-			return nil, errors.New("wrong blob size - should never happen")
-		}
-
-		// Compute the extended cells from the (non-extended) blob.
-		cells, err := kzg.ComputeCells(&kzgBlob)
-		if err != nil {
-			return nil, errors.Wrap(err, "compute cells")
-		}
-
-		var proofs []kzg.Proof
-		for idx := uint64(i) * numberOfColumns; idx < (uint64(i)+1)*numberOfColumns; idx++ {
-			var kzgProof kzg.Proof
-			if copy(kzgProof[:], cellProofs[idx]) != len(kzgProof) {
-				return nil, errors.New("wrong KZG proof size - should never happen")
-			}
-
-			proofs = append(proofs, kzgProof)
-		}
-
-		cellsProofs := kzg.CellsAndProofs{Cells: cells, Proofs: proofs}
-		cellsAndProofs = append(cellsAndProofs, cellsProofs)
-	}
-
-	dataColumnSidecars, err := DataColumnSidecars(block, cellsAndProofs)
-	if err != nil {
-		return nil, errors.Wrap(err, "data column sidcars")
-	}
-
-	return dataColumnSidecars, nil
+	return reconstructedVerifiedRoSidecars, nil
 }
 
 // ReconstructBlobs constructs verified read only blobs sidecars from verified read only blob sidecars.
@@ -256,6 +193,89 @@ func ReconstructBlobs(block blocks.ROBlock, verifiedDataColumnSidecars []blocks.
 	return blobSidecars, nil
 }
 
+// ComputeCellsAndProofsFromFlat computes the cells and proofs from blobs and cell flat proofs.
+func ComputeCellsAndProofsFromFlat(blobs [][]byte, cellProofs [][]byte) ([]kzg.CellsAndProofs, error) {
+	numberOfColumns := params.BeaconConfig().NumberOfColumns
+	blobCount := uint64(len(blobs))
+	cellProofsCount := uint64(len(cellProofs))
+
+	cellsCount := blobCount * numberOfColumns
+	if cellsCount != cellProofsCount {
+		return nil, ErrBlobsCellsProofsMismatch
+	}
+
+	cellsAndProofs := make([]kzg.CellsAndProofs, 0, blobCount)
+	for i, blob := range blobs {
+		var kzgBlob kzg.Blob
+		if copy(kzgBlob[:], blob) != len(kzgBlob) {
+			return nil, errors.New("wrong blob size - should never happen")
+		}
+
+		// Compute the extended cells from the (non-extended) blob.
+		cells, err := kzg.ComputeCells(&kzgBlob)
+		if err != nil {
+			return nil, errors.Wrap(err, "compute cells")
+		}
+
+		var proofs []kzg.Proof
+		for idx := uint64(i) * numberOfColumns; idx < (uint64(i)+1)*numberOfColumns; idx++ {
+			var kzgProof kzg.Proof
+			if copy(kzgProof[:], cellProofs[idx]) != len(kzgProof) {
+				return nil, errors.New("wrong KZG proof size - should never happen")
+			}
+
+			proofs = append(proofs, kzgProof)
+		}
+
+		cellsProofs := kzg.CellsAndProofs{Cells: cells, Proofs: proofs}
+		cellsAndProofs = append(cellsAndProofs, cellsProofs)
+	}
+
+	return cellsAndProofs, nil
+}
+
+// ComputeCellsAndProofs computes the cells and proofs from blobs and cell proofs.
+func ComputeCellsAndProofsFromStructured(blobsAndProofs []*pb.BlobAndProofV2) ([]kzg.CellsAndProofs, error) {
+	numberOfColumns := params.BeaconConfig().NumberOfColumns
+
+	cellsAndProofs := make([]kzg.CellsAndProofs, 0, len(blobsAndProofs))
+	for _, blobAndProof := range blobsAndProofs {
+		if blobAndProof == nil {
+			return nil, ErrNilBlobAndProof
+		}
+
+		var kzgBlob kzg.Blob
+		if copy(kzgBlob[:], blobAndProof.Blob) != len(kzgBlob) {
+			return nil, errors.New("wrong blob size - should never happen")
+		}
+
+		// Compute the extended cells from the (non-extended) blob.
+		cells, err := kzg.ComputeCells(&kzgBlob)
+		if err != nil {
+			return nil, errors.Wrap(err, "compute cells")
+		}
+
+		kzgProofs := make([]kzg.Proof, 0, numberOfColumns*kzg.BytesPerProof)
+		for _, kzgProofBytes := range blobAndProof.KzgProofs {
+			if len(kzgProofBytes) != kzg.BytesPerProof {
+				return nil, errors.New("wrong KZG proof size - should never happen")
+			}
+
+			var kzgProof kzg.Proof
+			if copy(kzgProof[:], kzgProofBytes) != len(kzgProof) {
+				return nil, errors.New("wrong copied KZG proof size - should never happen")
+			}
+
+			kzgProofs = append(kzgProofs, kzgProof)
+		}
+
+		cellsProofs := kzg.CellsAndProofs{Cells: cells, Proofs: kzgProofs}
+		cellsAndProofs = append(cellsAndProofs, cellsProofs)
+	}
+
+	return cellsAndProofs, nil
+}
+
 // blobSidecarsFromDataColumnSidecars converts verified data column sidecars to verified blob sidecars.
 func blobSidecarsFromDataColumnSidecars(roBlock blocks.ROBlock, dataColumnSidecars []blocks.VerifiedRODataColumn, indices []int) ([]*blocks.VerifiedROBlob, error) {
 	referenceSidecar := dataColumnSidecars[0]

beacon-chain/core/peerdas/reconstruction_test.go

@@ -9,7 +9,7 @@ import (
 	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
-	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
+	pb "github.com/OffchainLabs/prysm/v6/proto/engine/v1"
 	"github.com/OffchainLabs/prysm/v6/testing/require"
 	"github.com/OffchainLabs/prysm/v6/testing/util"
 	"github.com/pkg/errors"
@@ -124,50 +124,6 @@ func TestReconstructDataColumnSidecars(t *testing.T) {
 	})
 }
 
-func TestConstructDataColumnSidecars(t *testing.T) {
-	const (
-		blobCount    = 3
-		cellsPerBlob = fieldparams.CellsPerBlob
-	)
-
-	numberOfColumns := params.BeaconConfig().NumberOfColumns
-
-	// Start the trusted setup.
-	err := kzg.Start()
-	require.NoError(t, err)
-
-	roBlock, _, baseVerifiedRoSidecars := util.GenerateTestFuluBlockWithSidecars(t, blobCount)
-
-	// Extract blobs and proofs from the sidecars.
-	blobs := make([][]byte, 0, blobCount)
-	cellProofs := make([][]byte, 0, cellsPerBlob)
-	for blobIndex := range blobCount {
-		blob := make([]byte, 0, cellsPerBlob)
-		for columnIndex := range cellsPerBlob {
-			cell := baseVerifiedRoSidecars[columnIndex].Column[blobIndex]
-			blob = append(blob, cell...)
-		}
-
-		blobs = append(blobs, blob)
-
-		for columnIndex := range numberOfColumns {
-			cellProof := baseVerifiedRoSidecars[columnIndex].KzgProofs[blobIndex]
-			cellProofs = append(cellProofs, cellProof)
-		}
-	}
-
-	actual, err := peerdas.ConstructDataColumnSidecars(roBlock, blobs, cellProofs)
-	require.NoError(t, err)
-
-	// Extract the base verified ro sidecars into sidecars.
-	expected := make([]*ethpb.DataColumnSidecar, 0, len(baseVerifiedRoSidecars))
-	for _, verifiedRoSidecar := range baseVerifiedRoSidecars {
-		expected = append(expected, verifiedRoSidecar.DataColumnSidecar)
-	}
-
-	require.DeepSSZEqual(t, expected, actual)
-}
-
 func TestReconstructBlobs(t *testing.T) {
 	// Start the trusted setup.
 	err := kzg.Start()
@@ -250,7 +206,7 @@ func TestReconstructBlobs(t *testing.T) {
 		// Compute cells and proofs from blob sidecars.
 		var wg errgroup.Group
 		blobs := make([][]byte, blobCount)
-		cellsAndProofs := make([]kzg.CellsAndProofs, blobCount)
+		inputCellsAndProofs := make([]kzg.CellsAndProofs, blobCount)
 		for i := range blobCount {
 			blob := roBlobSidecars[i].Blob
 			blobs[i] = blob
@@ -267,7 +223,7 @@ func TestReconstructBlobs(t *testing.T) {
 
 				// It is safe for multiple goroutines to concurrently write to the same slice,
 				// as long as they are writing to different indices, which is the case here.
-				cellsAndProofs[i] = cp
+				inputCellsAndProofs[i] = cp
 
 				return nil
 			})
@@ -278,25 +234,24 @@ func TestReconstructBlobs(t *testing.T) {
 
 		// Flatten proofs.
 		cellProofs := make([][]byte, 0, blobCount*numberOfColumns)
-		for _, cp := range cellsAndProofs {
+		for _, cp := range inputCellsAndProofs {
 			for _, proof := range cp.Proofs {
 				cellProofs = append(cellProofs, proof[:])
 			}
 		}
 
-		// Construct data column sidecars.
-		// It is OK to use the public function `ConstructDataColumnSidecars`, as long as
-		// `TestConstructDataColumnSidecars` tests pass.
-		dataColumnSidecars, err := peerdas.ConstructDataColumnSidecars(roBlock, blobs, cellProofs)
+		// Compute celles and proofs from the blobs and cell proofs.
+		cellsAndProofs, err := peerdas.ComputeCellsAndProofsFromFlat(blobs, cellProofs)
+		require.NoError(t, err)
+
+		// Construct data column sidears from the signed block and cells and proofs.
+		roDataColumnSidecars, err := peerdas.DataColumnSidecars(cellsAndProofs, peerdas.PopulateFromBlock(roBlock))
 		require.NoError(t, err)
 
 		// Convert to verified data column sidecars.
-		verifiedRoSidecars := make([]blocks.VerifiedRODataColumn, 0, len(dataColumnSidecars))
-		for _, dataColumnSidecar := range dataColumnSidecars {
-			roSidecar, err := blocks.NewRODataColumn(dataColumnSidecar)
-			require.NoError(t, err)
-
-			verifiedRoSidecar := blocks.NewVerifiedRODataColumn(roSidecar)
+		verifiedRoSidecars := make([]blocks.VerifiedRODataColumn, 0, len(roDataColumnSidecars))
+		for _, roDataColumnSidecar := range roDataColumnSidecars {
+			verifiedRoSidecar := blocks.NewVerifiedRODataColumn(roDataColumnSidecar)
 			verifiedRoSidecars = append(verifiedRoSidecars, verifiedRoSidecar)
 		}
 
@@ -339,3 +294,162 @@ func TestReconstructBlobs(t *testing.T) {
 	})
 
 }
+
+func TestComputeCellsAndProofsFromFlat(t *testing.T) {
+	// Start the trusted setup.
+	err := kzg.Start()
+	require.NoError(t, err)
+
+	t.Run("mismatched blob and proof counts", func(t *testing.T) {
+		numberOfColumns := params.BeaconConfig().NumberOfColumns
+
+		// Create one blob but proofs for two blobs
+		blobs := [][]byte{{}}
+
+		// Create proofs for 2 blobs worth of columns
+		cellProofs := make([][]byte, 2*numberOfColumns)
+
+		_, err := peerdas.ComputeCellsAndProofsFromFlat(blobs, cellProofs)
+		require.ErrorIs(t, err, peerdas.ErrBlobsCellsProofsMismatch)
+	})
+
+	t.Run("nominal", func(t *testing.T) {
+		const blobCount = 2
+		numberOfColumns := params.BeaconConfig().NumberOfColumns
+
+		// Generate test blobs
+		_, roBlobSidecars := util.GenerateTestElectraBlockWithSidecar(t, [fieldparams.RootLength]byte{}, 42, blobCount)
+
+		// Extract blobs and compute expected cells and proofs
+		blobs := make([][]byte, blobCount)
+		expectedCellsAndProofs := make([]kzg.CellsAndProofs, blobCount)
+		var wg errgroup.Group
+
+		for i := range blobCount {
+			blob := roBlobSidecars[i].Blob
+			blobs[i] = blob
+
+			wg.Go(func() error {
+				var kzgBlob kzg.Blob
+				count := copy(kzgBlob[:], blob)
+				require.Equal(t, len(kzgBlob), count)
+
+				cp, err := kzg.ComputeCellsAndKZGProofs(&kzgBlob)
+				if err != nil {
+					return errors.Wrapf(err, "compute cells and kzg proofs for blob %d", i)
+				}
+
+				expectedCellsAndProofs[i] = cp
+				return nil
+			})
+		}
+
+		err := wg.Wait()
+		require.NoError(t, err)
+
+		// Flatten proofs
+		cellProofs := make([][]byte, 0, blobCount*numberOfColumns)
+		for _, cp := range expectedCellsAndProofs {
+			for _, proof := range cp.Proofs {
+				cellProofs = append(cellProofs, proof[:])
+			}
+		}
+
+		// Test ComputeCellsAndProofs
+		actualCellsAndProofs, err := peerdas.ComputeCellsAndProofsFromFlat(blobs, cellProofs)
+		require.NoError(t, err)
+		require.Equal(t, blobCount, len(actualCellsAndProofs))
+
+		// Verify the results match expected
+		for i := range blobCount {
+			require.Equal(t, len(expectedCellsAndProofs[i].Cells), len(actualCellsAndProofs[i].Cells))
+			require.Equal(t, len(expectedCellsAndProofs[i].Proofs), len(actualCellsAndProofs[i].Proofs))
+
+			// Compare cells
+			for j, expectedCell := range expectedCellsAndProofs[i].Cells {
+				require.Equal(t, expectedCell, actualCellsAndProofs[i].Cells[j])
+			}
+
+			// Compare proofs
+			for j, expectedProof := range expectedCellsAndProofs[i].Proofs {
+				require.Equal(t, expectedProof, actualCellsAndProofs[i].Proofs[j])
+			}
+		}
+	})
+}
+
+func TestComputeCellsAndProofsFromStructured(t *testing.T) {
+	t.Run("nil blob and proof", func(t *testing.T) {
+		_, err := peerdas.ComputeCellsAndProofsFromStructured([]*pb.BlobAndProofV2{nil})
+		require.ErrorIs(t, err, peerdas.ErrNilBlobAndProof)
+	})
+
+	t.Run("nominal", func(t *testing.T) {
+		// Start the trusted setup.
+		err := kzg.Start()
+		require.NoError(t, err)
+
+		const blobCount = 2
+
+		// Generate test blobs
+		_, roBlobSidecars := util.GenerateTestElectraBlockWithSidecar(t, [fieldparams.RootLength]byte{}, 42, blobCount)
+
+		// Extract blobs and compute expected cells and proofs
+		blobsAndProofs := make([]*pb.BlobAndProofV2, blobCount)
+		expectedCellsAndProofs := make([]kzg.CellsAndProofs, blobCount)
+
+		var wg errgroup.Group
+		for i := range blobCount {
+			blob := roBlobSidecars[i].Blob
+
+			wg.Go(func() error {
+				var kzgBlob kzg.Blob
+				count := copy(kzgBlob[:], blob)
+				require.Equal(t, len(kzgBlob), count)
+
+				cellsAndProofs, err := kzg.ComputeCellsAndKZGProofs(&kzgBlob)
+				if err != nil {
+					return errors.Wrapf(err, "compute cells and kzg proofs for blob %d", i)
+				}
+				expectedCellsAndProofs[i] = cellsAndProofs
+
+				kzgProofs := make([][]byte, 0, len(cellsAndProofs.Proofs))
+				for _, proof := range cellsAndProofs.Proofs {
+					kzgProofs = append(kzgProofs, proof[:])
+				}
+
+				blobAndProof := &pb.BlobAndProofV2{
+					Blob:      blob,
+					KzgProofs: kzgProofs,
+				}
+				blobsAndProofs[i] = blobAndProof
+
+				return nil
+			})
+		}
+
+		err = wg.Wait()
+		require.NoError(t, err)
+
+		// Test ComputeCellsAndProofs
+		actualCellsAndProofs, err := peerdas.ComputeCellsAndProofsFromStructured(blobsAndProofs)
+		require.NoError(t, err)
+		require.Equal(t, blobCount, len(actualCellsAndProofs))
+
+		// Verify the results match expected
+		for i := range blobCount {
+			require.Equal(t, len(expectedCellsAndProofs[i].Cells), len(actualCellsAndProofs[i].Cells))
+			require.Equal(t, len(expectedCellsAndProofs[i].Proofs), len(actualCellsAndProofs[i].Proofs))
+
+			// Compare cells
+			for j, expectedCell := range expectedCellsAndProofs[i].Cells {
+				require.Equal(t, expectedCell, actualCellsAndProofs[i].Cells[j])
+			}
+
+			// Compare proofs
+			for j, expectedProof := range expectedCellsAndProofs[i].Proofs {
+				require.Equal(t, expectedProof, actualCellsAndProofs[i].Proofs[j])
+			}
+		}
+	})
+}

beacon-chain/core/peerdas/validator.go

@@ -1,12 +1,76 @@
 package peerdas
 
 import (
+	"time"
+
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/kzg"
 	beaconState "github.com/OffchainLabs/prysm/v6/beacon-chain/state"
+	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v6/config/params"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
+	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/pkg/errors"
 )
 
+var (
+	ErrNilSignedBlockOrEmptyCellsAndProofs = errors.New("nil signed block or empty cells and proofs")
+	ErrSizeMismatch                        = errors.New("mismatch in the number of blob KZG commitments and cellsAndProofs")
+	ErrNotEnoughDataColumnSidecars         = errors.New("not enough columns")
+	ErrDataColumnSidecarsNotSortedByIndex  = errors.New("data column sidecars are not sorted by index")
+)
+
+var (
+	_ ConstructionPopulator = (*BlockReconstructionSource)(nil)
+	_ ConstructionPopulator = (*SidecarReconstructionSource)(nil)
+)
+
+const (
+	BlockType   = "BeaconBlock"
+	SidecarType = "DataColumnSidecar"
+)
+
+type (
+	// ConstructionPopulator is an interface that can be satisfied by a type that can use data from a struct
+	// like a DataColumnSidecar or a BeaconBlock to set the fields in a data column sidecar that cannot
+	// be obtained from the engine api.
+	ConstructionPopulator interface {
+		Slot() primitives.Slot
+		Root() [fieldparams.RootLength]byte
+		ProposerIndex() primitives.ValidatorIndex
+		Commitments() ([][]byte, error)
+		Type() string
+
+		extract() (*blockInfo, error)
+	}
+
+	// BlockReconstructionSource is a ConstructionPopulator that uses a beacon block as the source of data
+	BlockReconstructionSource struct {
+		blocks.ROBlock
+	}
+
+	// DataColumnSidecar is a ConstructionPopulator that uses a data column sidecar as the source of data
+	SidecarReconstructionSource struct {
+		blocks.VerifiedRODataColumn
+	}
+
+	blockInfo struct {
+		signedBlockHeader *ethpb.SignedBeaconBlockHeader
+		kzgCommitments    [][]byte
+		kzgInclusionProof [][]byte
+	}
+)
+
+// PopulateFromBlock creates a BlockReconstructionSource from a beacon block
+func PopulateFromBlock(block blocks.ROBlock) *BlockReconstructionSource {
+	return &BlockReconstructionSource{ROBlock: block}
+}
+
+// PopulateFromSidecar creates a SidecarReconstructionSource from a data column sidecar
+func PopulateFromSidecar(sidecar blocks.VerifiedRODataColumn) *SidecarReconstructionSource {
+	return &SidecarReconstructionSource{VerifiedRODataColumn: sidecar}
+}
+
 // ValidatorsCustodyRequirement returns the number of custody groups regarding the validator indices attached to the beacon node.
 // https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/validator.md#validator-custody
 func ValidatorsCustodyRequirement(state beaconState.ReadOnlyBeaconState, validatorsIndex map[primitives.ValidatorIndex]bool) (uint64, error) {
@@ -28,3 +92,158 @@ func ValidatorsCustodyRequirement(state beaconState.ReadOnlyBeaconState, validat
 	count := totalNodeBalance / balancePerAdditionalCustodyGroup
 	return min(max(count, validatorCustodyRequirement), numberOfCustodyGroups), nil
 }
+
+// DataColumnSidecars, given ConstructionPopulator and the cells/proofs associated with each blob in the
+// block, assembles sidecars which can be distributed to peers.
+// This is an adapted version of
+// https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/validator.md#get_data_column_sidecars,
+// which is designed to be used both when constructing sidecars from a block and from a sidecar, replacing
+// https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/validator.md#get_data_column_sidecars_from_block and
+// https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/validator.md#get_data_column_sidecars_from_column_sidecar
+func DataColumnSidecars(rows []kzg.CellsAndProofs, src ConstructionPopulator) ([]blocks.RODataColumn, error) {
+	if len(rows) == 0 {
+		return nil, nil
+	}
+	start := time.Now()
+	cells, proofs, err := rotateRowsToCols(rows, params.BeaconConfig().NumberOfColumns)
+	if err != nil {
+		return nil, errors.Wrap(err, "rotate cells and proofs")
+	}
+	info, err := src.extract()
+	if err != nil {
+		return nil, errors.Wrap(err, "extract block info")
+	}
+
+	maxIdx := params.BeaconConfig().NumberOfColumns
+	roSidecars := make([]blocks.RODataColumn, 0, maxIdx)
+	for idx := range maxIdx {
+		sidecar := &ethpb.DataColumnSidecar{
+			Index:                        idx,
+			Column:                       cells[idx],
+			KzgCommitments:               info.kzgCommitments,
+			KzgProofs:                    proofs[idx],
+			SignedBlockHeader:            info.signedBlockHeader,
+			KzgCommitmentsInclusionProof: info.kzgInclusionProof,
+		}
+
+		if len(sidecar.KzgCommitments) != len(sidecar.Column) || len(sidecar.KzgCommitments) != len(sidecar.KzgProofs) {
+			return nil, ErrSizeMismatch
+		}
+
+		roSidecar, err := blocks.NewRODataColumnWithRoot(sidecar, src.Root())
+		if err != nil {
+			return nil, errors.Wrap(err, "new ro data column")
+		}
+		roSidecars = append(roSidecars, roSidecar)
+	}
+
+	dataColumnComputationTime.Observe(float64(time.Since(start).Milliseconds()))
+	return roSidecars, nil
+}
+
+// Slot returns the slot of the source
+func (s *BlockReconstructionSource) Slot() primitives.Slot {
+	return s.Block().Slot()
+}
+
+// ProposerIndex returns the proposer index of the source
+func (s *BlockReconstructionSource) ProposerIndex() primitives.ValidatorIndex {
+	return s.Block().ProposerIndex()
+}
+
+// Commitments returns the blob KZG commitments of the source
+func (s *BlockReconstructionSource) Commitments() ([][]byte, error) {
+	c, err := s.Block().Body().BlobKzgCommitments()
+
+	if err != nil {
+		return nil, errors.Wrap(err, "blob KZG commitments")
+	}
+
+	return c, nil
+}
+
+// Type returns the type of the source
+func (s *BlockReconstructionSource) Type() string {
+	return BlockType
+}
+
+// extract extracts the block information from the source
+func (b *BlockReconstructionSource) extract() (*blockInfo, error) {
+	block := b.Block()
+
+	header, err := b.Header()
+	if err != nil {
+		return nil, errors.Wrap(err, "header")
+	}
+
+	commitments, err := block.Body().BlobKzgCommitments()
+	if err != nil {
+		return nil, errors.Wrap(err, "commitments")
+	}
+
+	inclusionProof, err := blocks.MerkleProofKZGCommitments(block.Body())
+	if err != nil {
+		return nil, errors.Wrap(err, "merkle proof kzg commitments")
+	}
+
+	info := &blockInfo{
+		signedBlockHeader: header,
+		kzgCommitments:    commitments,
+		kzgInclusionProof: inclusionProof,
+	}
+
+	return info, nil
+}
+
+// rotateRowsToCols takes a 2D slice of cells and proofs, where the x is rows (blobs) and y is columns,
+// and returns a 2D slice where x is columns and y is rows.
+func rotateRowsToCols(rows []kzg.CellsAndProofs, numCols uint64) ([][][]byte, [][][]byte, error) {
+	if len(rows) == 0 {
+		return nil, nil, nil
+	}
+	cellCols := make([][][]byte, numCols)
+	proofCols := make([][][]byte, numCols)
+	for i, cp := range rows {
+		if uint64(len(cp.Cells)) != numCols {
+			return nil, nil, errors.Wrap(ErrNotEnoughDataColumnSidecars, "not enough cells")
+		}
+		if len(cp.Cells) != len(cp.Proofs) {
+			return nil, nil, errors.Wrap(ErrNotEnoughDataColumnSidecars, "not enough proofs")
+		}
+		for j := uint64(0); j < numCols; j++ {
+			if i == 0 {
+				cellCols[j] = make([][]byte, len(rows))
+				proofCols[j] = make([][]byte, len(rows))
+			}
+			cellCols[j][i] = cp.Cells[j][:]
+			proofCols[j][i] = cp.Proofs[j][:]
+		}
+	}
+	return cellCols, proofCols, nil
+}
+
+// Root returns the block root of the source
+func (s *SidecarReconstructionSource) Root() [fieldparams.RootLength]byte {
+	return s.BlockRoot()
+}
+
+// Commmitments returns the blob KZG commitments of the source
+func (s *SidecarReconstructionSource) Commitments() ([][]byte, error) {
+	return s.KzgCommitments, nil
+}
+
+// Type returns the type of the source
+func (s *SidecarReconstructionSource) Type() string {
+	return SidecarType
+}
+
+// extract extracts the block information from the source
+func (s *SidecarReconstructionSource) extract() (*blockInfo, error) {
+	info := &blockInfo{
+		signedBlockHeader: s.SignedBlockHeader,
+		kzgCommitments:    s.KzgCommitments,
+		kzgInclusionProof: s.KzgCommitmentsInclusionProof,
+	}
+
+	return info, nil
+}

beacon-chain/core/peerdas/validator_test.go

@@ -3,11 +3,15 @@ package peerdas_test
 import (
 	"testing"
 
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/kzg"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
 	state_native "github.com/OffchainLabs/prysm/v6/beacon-chain/state/state-native"
+	"github.com/OffchainLabs/prysm/v6/config/params"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v6/testing/require"
+	"github.com/OffchainLabs/prysm/v6/testing/util"
 )
 
 func TestValidatorsCustodyRequirement(t *testing.T) {
@@ -53,3 +57,218 @@ func TestValidatorsCustodyRequirement(t *testing.T) {
 		})
 	}
 }
+
+func TestDataColumnSidecars(t *testing.T) {
+	t.Run("sizes mismatch", func(t *testing.T) {
+		// Create a protobuf signed beacon block.
+		signedBeaconBlockPb := util.NewBeaconBlockDeneb()
+
+		// Create a signed beacon block from the protobuf.
+		signedBeaconBlock, err := blocks.NewSignedBeaconBlock(signedBeaconBlockPb)
+		require.NoError(t, err)
+
+		// Create cells and proofs.
+		cellsAndProofs := []kzg.CellsAndProofs{
+			{
+				Cells:  make([]kzg.Cell, params.BeaconConfig().NumberOfColumns),
+				Proofs: make([]kzg.Proof, params.BeaconConfig().NumberOfColumns),
+			},
+		}
+
+		rob, err := blocks.NewROBlock(signedBeaconBlock)
+		require.NoError(t, err)
+		_, err = peerdas.DataColumnSidecars(cellsAndProofs, peerdas.PopulateFromBlock(rob))
+		require.ErrorIs(t, err, peerdas.ErrSizeMismatch)
+	})
+
+	t.Run("cells array too short for column index", func(t *testing.T) {
+		// Create a Fulu block with a blob commitment.
+		signedBeaconBlockPb := util.NewBeaconBlockFulu()
+		signedBeaconBlockPb.Block.Body.BlobKzgCommitments = [][]byte{make([]byte, 48)}
+
+		// Create a signed beacon block from the protobuf.
+		signedBeaconBlock, err := blocks.NewSignedBeaconBlock(signedBeaconBlockPb)
+		require.NoError(t, err)
+
+		// Create cells and proofs with insufficient cells for the number of columns.
+		// This simulates a scenario where cellsAndProofs has fewer cells than expected columns.
+		cellsAndProofs := []kzg.CellsAndProofs{
+			{
+				Cells:  make([]kzg.Cell, 10),  // Only 10 cells
+				Proofs: make([]kzg.Proof, 10), // Only 10 proofs
+			},
+		}
+
+		// This should fail because the function will try to access columns up to NumberOfColumns
+		// but we only have 10 cells/proofs.
+		rob, err := blocks.NewROBlock(signedBeaconBlock)
+		require.NoError(t, err)
+		_, err = peerdas.DataColumnSidecars(cellsAndProofs, peerdas.PopulateFromBlock(rob))
+		require.ErrorIs(t, err, peerdas.ErrNotEnoughDataColumnSidecars)
+	})
+
+	t.Run("proofs array too short for column index", func(t *testing.T) {
+		// Create a Fulu block with a blob commitment.
+		signedBeaconBlockPb := util.NewBeaconBlockFulu()
+		signedBeaconBlockPb.Block.Body.BlobKzgCommitments = [][]byte{make([]byte, 48)}
+
+		// Create a signed beacon block from the protobuf.
+		signedBeaconBlock, err := blocks.NewSignedBeaconBlock(signedBeaconBlockPb)
+		require.NoError(t, err)
+
+		// Create cells and proofs with sufficient cells but insufficient proofs.
+		numberOfColumns := params.BeaconConfig().NumberOfColumns
+		cellsAndProofs := []kzg.CellsAndProofs{
+			{
+				Cells:  make([]kzg.Cell, numberOfColumns),
+				Proofs: make([]kzg.Proof, 5), // Only 5 proofs, less than columns
+			},
+		}
+
+		// This should fail when trying to access proof beyond index 4.
+		rob, err := blocks.NewROBlock(signedBeaconBlock)
+		require.NoError(t, err)
+		_, err = peerdas.DataColumnSidecars(cellsAndProofs, peerdas.PopulateFromBlock(rob))
+		require.ErrorIs(t, err, peerdas.ErrNotEnoughDataColumnSidecars)
+		require.ErrorContains(t, "not enough proofs", err)
+	})
+
+	t.Run("nominal", func(t *testing.T) {
+		// Create a Fulu block with blob commitments.
+		signedBeaconBlockPb := util.NewBeaconBlockFulu()
+		commitment1 := make([]byte, 48)
+		commitment2 := make([]byte, 48)
+
+		// Set different values to distinguish commitments
+		commitment1[0] = 0x01
+		commitment2[0] = 0x02
+		signedBeaconBlockPb.Block.Body.BlobKzgCommitments = [][]byte{commitment1, commitment2}
+
+		// Create a signed beacon block from the protobuf.
+		signedBeaconBlock, err := blocks.NewSignedBeaconBlock(signedBeaconBlockPb)
+		require.NoError(t, err)
+
+		// Create cells and proofs with correct dimensions.
+		numberOfColumns := params.BeaconConfig().NumberOfColumns
+		cellsAndProofs := []kzg.CellsAndProofs{
+			{
+				Cells:  make([]kzg.Cell, numberOfColumns),
+				Proofs: make([]kzg.Proof, numberOfColumns),
+			},
+			{
+				Cells:  make([]kzg.Cell, numberOfColumns),
+				Proofs: make([]kzg.Proof, numberOfColumns),
+			},
+		}
+
+		// Set distinct values in cells and proofs for testing
+		for i := range numberOfColumns {
+			cellsAndProofs[0].Cells[i][0] = byte(i)
+			cellsAndProofs[0].Proofs[i][0] = byte(i)
+			cellsAndProofs[1].Cells[i][0] = byte(i + 128)
+			cellsAndProofs[1].Proofs[i][0] = byte(i + 128)
+		}
+
+		rob, err := blocks.NewROBlock(signedBeaconBlock)
+		require.NoError(t, err)
+		sidecars, err := peerdas.DataColumnSidecars(cellsAndProofs, peerdas.PopulateFromBlock(rob))
+		require.NoError(t, err)
+		require.NotNil(t, sidecars)
+		require.Equal(t, int(numberOfColumns), len(sidecars))
+
+		// Verify each sidecar has the expected structure
+		for i, sidecar := range sidecars {
+			require.Equal(t, uint64(i), sidecar.Index)
+			require.Equal(t, 2, len(sidecar.Column))
+			require.Equal(t, 2, len(sidecar.KzgCommitments))
+			require.Equal(t, 2, len(sidecar.KzgProofs))
+
+			// Verify commitments match what we set
+			require.DeepEqual(t, commitment1, sidecar.KzgCommitments[0])
+			require.DeepEqual(t, commitment2, sidecar.KzgCommitments[1])
+
+			// Verify column data comes from the correct cells
+			require.Equal(t, byte(i), sidecar.Column[0][0])
+			require.Equal(t, byte(i+128), sidecar.Column[1][0])
+
+			// Verify proofs come from the correct proofs
+			require.Equal(t, byte(i), sidecar.KzgProofs[0][0])
+			require.Equal(t, byte(i+128), sidecar.KzgProofs[1][0])
+		}
+	})
+}
+
+func TestReconstructionSource(t *testing.T) {
+	// Create a Fulu block with blob commitments.
+	signedBeaconBlockPb := util.NewBeaconBlockFulu()
+	commitment1 := make([]byte, 48)
+	commitment2 := make([]byte, 48)
+
+	// Set different values to distinguish commitments
+	commitment1[0] = 0x01
+	commitment2[0] = 0x02
+	signedBeaconBlockPb.Block.Body.BlobKzgCommitments = [][]byte{commitment1, commitment2}
+
+	// Create a signed beacon block from the protobuf.
+	signedBeaconBlock, err := blocks.NewSignedBeaconBlock(signedBeaconBlockPb)
+	require.NoError(t, err)
+
+	// Create cells and proofs with correct dimensions.
+	numberOfColumns := params.BeaconConfig().NumberOfColumns
+	cellsAndProofs := []kzg.CellsAndProofs{
+		{
+			Cells:  make([]kzg.Cell, numberOfColumns),
+			Proofs: make([]kzg.Proof, numberOfColumns),
+		},
+		{
+			Cells:  make([]kzg.Cell, numberOfColumns),
+			Proofs: make([]kzg.Proof, numberOfColumns),
+		},
+	}
+
+	// Set distinct values in cells and proofs for testing
+	for i := range numberOfColumns {
+		cellsAndProofs[0].Cells[i][0] = byte(i)
+		cellsAndProofs[0].Proofs[i][0] = byte(i)
+		cellsAndProofs[1].Cells[i][0] = byte(i + 128)
+		cellsAndProofs[1].Proofs[i][0] = byte(i + 128)
+	}
+
+	rob, err := blocks.NewROBlock(signedBeaconBlock)
+	require.NoError(t, err)
+	sidecars, err := peerdas.DataColumnSidecars(cellsAndProofs, peerdas.PopulateFromBlock(rob))
+	require.NoError(t, err)
+	require.NotNil(t, sidecars)
+	require.Equal(t, int(numberOfColumns), len(sidecars))
+
+	t.Run("from block", func(t *testing.T) {
+		src := peerdas.PopulateFromBlock(rob)
+		require.Equal(t, rob.Block().Slot(), src.Slot())
+		require.Equal(t, rob.Root(), src.Root())
+		require.Equal(t, rob.Block().ProposerIndex(), src.ProposerIndex())
+
+		commitments, err := src.Commitments()
+		require.NoError(t, err)
+		require.Equal(t, 2, len(commitments))
+		require.DeepEqual(t, commitment1, commitments[0])
+		require.DeepEqual(t, commitment2, commitments[1])
+
+		require.Equal(t, peerdas.BlockType, src.Type())
+	})
+
+	t.Run("from sidecar", func(t *testing.T) {
+		referenceSidecar := blocks.NewVerifiedRODataColumn(sidecars[0])
+		src := peerdas.PopulateFromSidecar(referenceSidecar)
+		require.Equal(t, referenceSidecar.Slot(), src.Slot())
+		require.Equal(t, referenceSidecar.BlockRoot(), src.Root())
+		require.Equal(t, referenceSidecar.ProposerIndex(), src.ProposerIndex())
+
+		commitments, err := src.Commitments()
+		require.NoError(t, err)
+		require.Equal(t, 2, len(commitments))
+		require.DeepEqual(t, commitment1, commitments[0])
+		require.DeepEqual(t, commitment2, commitments[1])
+
+		require.Equal(t, peerdas.SidecarType, src.Type())
+	})
+}

beacon-chain/core/transition/transition_no_verify_sig.go

@@ -8,6 +8,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/altair"
 	b "github.com/OffchainLabs/prysm/v6/beacon-chain/core/blocks"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/electra"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/transition/interop"
 	v "github.com/OffchainLabs/prysm/v6/beacon-chain/core/validators"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
@@ -374,15 +375,18 @@ func ProcessBlockForStateRoot(
 }
 
 // This calls altair block operations.
-func altairOperations(
-	ctx context.Context,
-	st state.BeaconState,
-	beaconBlock interfaces.ReadOnlyBeaconBlock) (state.BeaconState, error) {
-	st, err := b.ProcessProposerSlashings(ctx, st, beaconBlock.Body().ProposerSlashings(), v.SlashValidator)
+func altairOperations(ctx context.Context, st state.BeaconState, beaconBlock interfaces.ReadOnlyBeaconBlock) (state.BeaconState, error) {
+	var err error
+
+	exitInfo := v.ExitInformation(st)
+	if err := helpers.UpdateTotalActiveBalanceCache(st, exitInfo.TotalActiveBalance); err != nil {
+		return nil, errors.Wrap(err, "could not update total active balance cache")
+	}
+	st, err = b.ProcessProposerSlashings(ctx, st, beaconBlock.Body().ProposerSlashings(), exitInfo)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not process altair proposer slashing")
 	}
-	st, err = b.ProcessAttesterSlashings(ctx, st, beaconBlock.Body().AttesterSlashings(), v.SlashValidator)
+	st, err = b.ProcessAttesterSlashings(ctx, st, beaconBlock.Body().AttesterSlashings(), exitInfo)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not process altair attester slashing")
 	}
@@ -393,7 +397,7 @@ func altairOperations(
 	if _, err := altair.ProcessDeposits(ctx, st, beaconBlock.Body().Deposits()); err != nil {
 		return nil, errors.Wrap(err, "could not process altair deposit")
 	}
-	st, err = b.ProcessVoluntaryExits(ctx, st, beaconBlock.Body().VoluntaryExits())
+	st, err = b.ProcessVoluntaryExits(ctx, st, beaconBlock.Body().VoluntaryExits(), exitInfo)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not process voluntary exits")
 	}
@@ -401,15 +405,18 @@ func altairOperations(
 }
 
 // This calls phase 0 block operations.
-func phase0Operations(
-	ctx context.Context,
-	st state.BeaconState,
-	beaconBlock interfaces.ReadOnlyBeaconBlock) (state.BeaconState, error) {
-	st, err := b.ProcessProposerSlashings(ctx, st, beaconBlock.Body().ProposerSlashings(), v.SlashValidator)
+func phase0Operations(ctx context.Context, st state.BeaconState, beaconBlock interfaces.ReadOnlyBeaconBlock) (state.BeaconState, error) {
+	var err error
+
+	exitInfo := v.ExitInformation(st)
+	if err := helpers.UpdateTotalActiveBalanceCache(st, exitInfo.TotalActiveBalance); err != nil {
+		return nil, errors.Wrap(err, "could not update total active balance cache")
+	}
+	st, err = b.ProcessProposerSlashings(ctx, st, beaconBlock.Body().ProposerSlashings(), exitInfo)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not process block proposer slashings")
 	}
-	st, err = b.ProcessAttesterSlashings(ctx, st, beaconBlock.Body().AttesterSlashings(), v.SlashValidator)
+	st, err = b.ProcessAttesterSlashings(ctx, st, beaconBlock.Body().AttesterSlashings(), exitInfo)
 	if err != nil {
 		return nil, errors.Wrap(err, "could not process block attester slashings")
 	}
@@ -420,5 +427,9 @@ func phase0Operations(
 	if _, err := altair.ProcessDeposits(ctx, st, beaconBlock.Body().Deposits()); err != nil {
 		return nil, errors.Wrap(err, "could not process deposits")
 	}
-	return b.ProcessVoluntaryExits(ctx, st, beaconBlock.Body().VoluntaryExits())
+	st, err = b.ProcessVoluntaryExits(ctx, st, beaconBlock.Body().VoluntaryExits(), exitInfo)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not process voluntary exits")
+	}
+	return st, nil
 }

beacon-chain/core/validators/validator.go

@@ -13,34 +13,55 @@ import (
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v6/math"
+	mathutil "github.com/OffchainLabs/prysm/v6/math"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v6/runtime/version"
 	"github.com/OffchainLabs/prysm/v6/time/slots"
 	"github.com/pkg/errors"
 )
 
+// ExitInfo provides information about validator exits in the state.
+type ExitInfo struct {
+	HighestExitEpoch   primitives.Epoch
+	Churn              uint64
+	TotalActiveBalance uint64
+}
+
 // ErrValidatorAlreadyExited is an error raised when trying to process an exit of
 // an already exited validator
 var ErrValidatorAlreadyExited = errors.New("validator already exited")
 
-// MaxExitEpochAndChurn returns the maximum non-FAR_FUTURE_EPOCH exit
-// epoch and the number of them
-func MaxExitEpochAndChurn(s state.BeaconState) (maxExitEpoch primitives.Epoch, churn uint64) {
+// ExitInformation returns information about validator exits.
+func ExitInformation(s state.BeaconState) *ExitInfo {
+	exitInfo := &ExitInfo{}
+
 	farFutureEpoch := params.BeaconConfig().FarFutureEpoch
+	currentEpoch := slots.ToEpoch(s.Slot())
+	totalActiveBalance := uint64(0)
+
 	err := s.ReadFromEveryValidator(func(idx int, val state.ReadOnlyValidator) error {
 		e := val.ExitEpoch()
 		if e != farFutureEpoch {
-			if e > maxExitEpoch {
-				maxExitEpoch = e
-				churn = 1
-			} else if e == maxExitEpoch {
-				churn++
+			if e > exitInfo.HighestExitEpoch {
+				exitInfo.HighestExitEpoch = e
+				exitInfo.Churn = 1
+			} else if e == exitInfo.HighestExitEpoch {
+				exitInfo.Churn++
 			}
 		}
+
+		// Calculate total active balance in the same loop
+		if helpers.IsActiveValidatorUsingTrie(val, currentEpoch) {
+			totalActiveBalance += val.EffectiveBalance()
+		}
+
 		return nil
 	})
 	_ = err
-	return
+
+	// Apply minimum balance as per spec
+	exitInfo.TotalActiveBalance = mathutil.Max(params.BeaconConfig().EffectiveBalanceIncrement, totalActiveBalance)
+	return exitInfo
 }
 
 // InitiateValidatorExit takes in validator index and updates
@@ -64,59 +85,117 @@ func MaxExitEpochAndChurn(s state.BeaconState) (maxExitEpoch primitives.Epoch, c
 //	    # Set validator exit epoch and withdrawable epoch
 //	    validator.exit_epoch = exit_queue_epoch
 //	    validator.withdrawable_epoch = Epoch(validator.exit_epoch + MIN_VALIDATOR_WITHDRAWABILITY_DELAY)
-func InitiateValidatorExit(ctx context.Context, s state.BeaconState, idx primitives.ValidatorIndex, exitQueueEpoch primitives.Epoch, churn uint64) (state.BeaconState, primitives.Epoch, error) {
+func InitiateValidatorExit(
+	ctx context.Context,
+	s state.BeaconState,
+	idx primitives.ValidatorIndex,
+	exitInfo *ExitInfo,
+) (state.BeaconState, error) {
 	validator, err := s.ValidatorAtIndex(idx)
 	if err != nil {
-		return nil, 0, err
+		return nil, err
 	}
 	if validator.ExitEpoch != params.BeaconConfig().FarFutureEpoch {
-		return s, validator.ExitEpoch, ErrValidatorAlreadyExited
+		return s, ErrValidatorAlreadyExited
 	}
 
 	// Compute exit queue epoch.
 	if s.Version() < version.Electra {
-		// Relevant spec code from phase0:
-		//
-		//	exit_epochs = [v.exit_epoch for v in state.validators if v.exit_epoch != FAR_FUTURE_EPOCH]
-		//	exit_queue_epoch = max(exit_epochs + [compute_activation_exit_epoch(get_current_epoch(state))])
-		//	exit_queue_churn = len([v for v in state.validators if v.exit_epoch == exit_queue_epoch])
-		//	if exit_queue_churn >= get_validator_churn_limit(state):
-		//	    exit_queue_epoch += Epoch(1)
-		exitableEpoch := helpers.ActivationExitEpoch(time.CurrentEpoch(s))
-		if exitableEpoch > exitQueueEpoch {
-			exitQueueEpoch = exitableEpoch
-			churn = 0
-		}
-		activeValidatorCount, err := helpers.ActiveValidatorCount(ctx, s, time.CurrentEpoch(s))
-		if err != nil {
-			return nil, 0, errors.Wrap(err, "could not get active validator count")
-		}
-		currentChurn := helpers.ValidatorExitChurnLimit(activeValidatorCount)
-
-		if churn >= currentChurn {
-			exitQueueEpoch, err = exitQueueEpoch.SafeAdd(1)
-			if err != nil {
-				return nil, 0, err
-			}
+		if err = initiateValidatorExitPreElectra(ctx, s, exitInfo); err != nil {
+			return nil, err
 		}
 	} else {
 		// [Modified in Electra:EIP7251]
 		// exit_queue_epoch = compute_exit_epoch_and_update_churn(state, validator.effective_balance)
 		var err error
-		exitQueueEpoch, err = s.ExitEpochAndUpdateChurn(primitives.Gwei(validator.EffectiveBalance))
+		exitInfo.HighestExitEpoch, err = s.ExitEpochAndUpdateChurn(primitives.Gwei(validator.EffectiveBalance))
 		if err != nil {
-			return nil, 0, err
+			return nil, err
 		}
 	}
-	validator.ExitEpoch = exitQueueEpoch
-	validator.WithdrawableEpoch, err = exitQueueEpoch.SafeAddEpoch(params.BeaconConfig().MinValidatorWithdrawabilityDelay)
+	validator.ExitEpoch = exitInfo.HighestExitEpoch
+	validator.WithdrawableEpoch, err = exitInfo.HighestExitEpoch.SafeAddEpoch(params.BeaconConfig().MinValidatorWithdrawabilityDelay)
 	if err != nil {
-		return nil, 0, err
+		return nil, err
 	}
 	if err := s.UpdateValidatorAtIndex(idx, validator); err != nil {
-		return nil, 0, err
+		return nil, err
 	}
-	return s, exitQueueEpoch, nil
+	return s, nil
+}
+
+// InitiateValidatorExitForTotalBal has the same functionality as InitiateValidatorExit,
+// the only difference being how total active balance is obtained. In InitiateValidatorExit
+// it is calculated inside the function and in InitiateValidatorExitForTotalBal it's a
+// function argument.
+func InitiateValidatorExitForTotalBal(
+	ctx context.Context,
+	s state.BeaconState,
+	idx primitives.ValidatorIndex,
+	exitInfo *ExitInfo,
+	totalActiveBalance primitives.Gwei,
+) (state.BeaconState, error) {
+	validator, err := s.ValidatorAtIndex(idx)
+	if err != nil {
+		return nil, err
+	}
+	if validator.ExitEpoch != params.BeaconConfig().FarFutureEpoch {
+		return s, ErrValidatorAlreadyExited
+	}
+
+	// Compute exit queue epoch.
+	if s.Version() < version.Electra {
+		if err = initiateValidatorExitPreElectra(ctx, s, exitInfo); err != nil {
+			return nil, err
+		}
+	} else {
+		// [Modified in Electra:EIP7251]
+		// exit_queue_epoch = compute_exit_epoch_and_update_churn(state, validator.effective_balance)
+		var err error
+		exitInfo.HighestExitEpoch, err = s.ExitEpochAndUpdateChurnForTotalBal(totalActiveBalance, primitives.Gwei(validator.EffectiveBalance))
+		if err != nil {
+			return nil, err
+		}
+	}
+	validator.ExitEpoch = exitInfo.HighestExitEpoch
+	validator.WithdrawableEpoch, err = exitInfo.HighestExitEpoch.SafeAddEpoch(params.BeaconConfig().MinValidatorWithdrawabilityDelay)
+	if err != nil {
+		return nil, err
+	}
+	if err := s.UpdateValidatorAtIndex(idx, validator); err != nil {
+		return nil, err
+	}
+	return s, nil
+}
+
+func initiateValidatorExitPreElectra(ctx context.Context, s state.BeaconState, exitInfo *ExitInfo) error {
+	// Relevant spec code from phase0:
+	//
+	//	exit_epochs = [v.exit_epoch for v in state.validators if v.exit_epoch != FAR_FUTURE_EPOCH]
+	//	exit_queue_epoch = max(exit_epochs + [compute_activation_exit_epoch(get_current_epoch(state))])
+	//	exit_queue_churn = len([v for v in state.validators if v.exit_epoch == exit_queue_epoch])
+	//	if exit_queue_churn >= get_validator_churn_limit(state):
+	//	    exit_queue_epoch += Epoch(1)
+	exitableEpoch := helpers.ActivationExitEpoch(time.CurrentEpoch(s))
+	if exitableEpoch > exitInfo.HighestExitEpoch {
+		exitInfo.HighestExitEpoch = exitableEpoch
+		exitInfo.Churn = 0
+	}
+	activeValidatorCount, err := helpers.ActiveValidatorCount(ctx, s, time.CurrentEpoch(s))
+	if err != nil {
+		return errors.Wrap(err, "could not get active validator count")
+	}
+	currentChurn := helpers.ValidatorExitChurnLimit(activeValidatorCount)
+	if exitInfo.Churn >= currentChurn {
+		exitInfo.HighestExitEpoch, err = exitInfo.HighestExitEpoch.SafeAdd(1)
+		if err != nil {
+			return err
+		}
+		exitInfo.Churn = 1
+	} else {
+		exitInfo.Churn = exitInfo.Churn + 1
+	}
+	return nil
 }
 
 // SlashValidator slashes the malicious validator's balance and awards
@@ -152,9 +231,12 @@ func InitiateValidatorExit(ctx context.Context, s state.BeaconState, idx primiti
 func SlashValidator(
 	ctx context.Context,
 	s state.BeaconState,
-	slashedIdx primitives.ValidatorIndex) (state.BeaconState, error) {
-	maxExitEpoch, churn := MaxExitEpochAndChurn(s)
-	s, _, err := InitiateValidatorExit(ctx, s, slashedIdx, maxExitEpoch, churn)
+	slashedIdx primitives.ValidatorIndex,
+	exitInfo *ExitInfo,
+) (state.BeaconState, error) {
+	var err error
+
+	s, err = InitiateValidatorExitForTotalBal(ctx, s, slashedIdx, exitInfo, primitives.Gwei(exitInfo.TotalActiveBalance))
 	if err != nil && !errors.Is(err, ErrValidatorAlreadyExited) {
 		return nil, errors.Wrapf(err, "could not initiate validator %d exit", slashedIdx)
 	}

beacon-chain/core/validators/validator_test.go

@@ -49,9 +49,11 @@ func TestInitiateValidatorExit_AlreadyExited(t *testing.T) {
 	}}
 	state, err := state_native.InitializeFromProtoPhase0(base)
 	require.NoError(t, err)
-	newState, epoch, err := validators.InitiateValidatorExit(t.Context(), state, 0, 199, 1)
+	exitInfo := &validators.ExitInfo{HighestExitEpoch: 199, Churn: 1}
+	newState, err := validators.InitiateValidatorExit(t.Context(), state, 0, exitInfo)
 	require.ErrorIs(t, err, validators.ErrValidatorAlreadyExited)
-	require.Equal(t, exitEpoch, epoch)
+	assert.Equal(t, primitives.Epoch(199), exitInfo.HighestExitEpoch)
+	assert.Equal(t, uint64(1), exitInfo.Churn)
 	v, err := newState.ValidatorAtIndex(0)
 	require.NoError(t, err)
 	assert.Equal(t, exitEpoch, v.ExitEpoch, "Already exited")
@@ -68,9 +70,11 @@ func TestInitiateValidatorExit_ProperExit(t *testing.T) {
 	}}
 	state, err := state_native.InitializeFromProtoPhase0(base)
 	require.NoError(t, err)
-	newState, epoch, err := validators.InitiateValidatorExit(t.Context(), state, idx, exitedEpoch+2, 1)
+	exitInfo := &validators.ExitInfo{HighestExitEpoch: exitedEpoch + 2, Churn: 1}
+	newState, err := validators.InitiateValidatorExit(t.Context(), state, idx, exitInfo)
 	require.NoError(t, err)
-	require.Equal(t, exitedEpoch+2, epoch)
+	assert.Equal(t, exitedEpoch+2, exitInfo.HighestExitEpoch)
+	assert.Equal(t, uint64(2), exitInfo.Churn)
 	v, err := newState.ValidatorAtIndex(idx)
 	require.NoError(t, err)
 	assert.Equal(t, exitedEpoch+2, v.ExitEpoch, "Exit epoch was not the highest")
@@ -88,9 +92,11 @@ func TestInitiateValidatorExit_ChurnOverflow(t *testing.T) {
 	}}
 	state, err := state_native.InitializeFromProtoPhase0(base)
 	require.NoError(t, err)
-	newState, epoch, err := validators.InitiateValidatorExit(t.Context(), state, idx, exitedEpoch+2, 4)
+	exitInfo := &validators.ExitInfo{HighestExitEpoch: exitedEpoch + 2, Churn: 4}
+	newState, err := validators.InitiateValidatorExit(t.Context(), state, idx, exitInfo)
 	require.NoError(t, err)
-	require.Equal(t, exitedEpoch+3, epoch)
+	assert.Equal(t, exitedEpoch+3, exitInfo.HighestExitEpoch)
+	assert.Equal(t, uint64(1), exitInfo.Churn)
 
 	// Because of exit queue overflow,
 	// validator who init exited has to wait one more epoch.
@@ -110,7 +116,8 @@ func TestInitiateValidatorExit_WithdrawalOverflows(t *testing.T) {
 	}}
 	state, err := state_native.InitializeFromProtoPhase0(base)
 	require.NoError(t, err)
-	_, _, err = validators.InitiateValidatorExit(t.Context(), state, 1, params.BeaconConfig().FarFutureEpoch-1, 1)
+	exitInfo := &validators.ExitInfo{HighestExitEpoch: params.BeaconConfig().FarFutureEpoch - 1, Churn: 1}
+	_, err = validators.InitiateValidatorExit(t.Context(), state, 1, exitInfo)
 	require.ErrorContains(t, "addition overflows", err)
 }
 
@@ -146,12 +153,11 @@ func TestInitiateValidatorExit_ProperExit_Electra(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, primitives.Gwei(0), ebtc)
 
-	newState, epoch, err := validators.InitiateValidatorExit(t.Context(), state, idx, 0, 0) // exitQueueEpoch and churn are not used in electra
+	newState, err := validators.InitiateValidatorExit(t.Context(), state, idx, &validators.ExitInfo{}) // exit info is not used in electra
 	require.NoError(t, err)
 
 	// Expect that the exit epoch is the next available epoch with max seed lookahead.
 	want := helpers.ActivationExitEpoch(exitedEpoch + 1)
-	require.Equal(t, want, epoch)
 	v, err := newState.ValidatorAtIndex(idx)
 	require.NoError(t, err)
 	assert.Equal(t, want, v.ExitEpoch, "Exit epoch was not the highest")
@@ -190,7 +196,7 @@ func TestSlashValidator_OK(t *testing.T) {
 	require.NoError(t, err, "Could not get proposer")
 	proposerBal, err := state.BalanceAtIndex(proposer)
 	require.NoError(t, err)
-	slashedState, err := validators.SlashValidator(t.Context(), state, slashedIdx)
+	slashedState, err := validators.SlashValidator(t.Context(), state, slashedIdx, validators.ExitInformation(state))
 	require.NoError(t, err, "Could not slash validator")
 	require.Equal(t, true, slashedState.Version() == version.Phase0)
 
@@ -244,7 +250,7 @@ func TestSlashValidator_Electra(t *testing.T) {
 	require.NoError(t, err, "Could not get proposer")
 	proposerBal, err := state.BalanceAtIndex(proposer)
 	require.NoError(t, err)
-	slashedState, err := validators.SlashValidator(t.Context(), state, slashedIdx)
+	slashedState, err := validators.SlashValidator(t.Context(), state, slashedIdx, validators.ExitInformation(state))
 	require.NoError(t, err, "Could not slash validator")
 	require.Equal(t, true, slashedState.Version() == version.Electra)
 
@@ -505,8 +511,8 @@ func TestValidatorMaxExitEpochAndChurn(t *testing.T) {
 	for _, tt := range tests {
 		s, err := state_native.InitializeFromProtoPhase0(tt.state)
 		require.NoError(t, err)
-		epoch, churn := validators.MaxExitEpochAndChurn(s)
-		require.Equal(t, tt.wantedEpoch, epoch)
-		require.Equal(t, tt.wantedChurn, churn)
+		exitInfo := validators.ExitInformation(s)
+		require.Equal(t, tt.wantedEpoch, exitInfo.HighestExitEpoch)
+		require.Equal(t, tt.wantedChurn, exitInfo.Churn)
 	}
 }

beacon-chain/db/filesystem/blob.go

@@ -122,18 +122,18 @@ type BlobStorage struct {
 func (bs *BlobStorage) WarmCache() {
 	start := time.Now()
 	if bs.layoutName == LayoutNameFlat {
-		log.Info("Blob filesystem cache warm-up started. This may take a few minutes.")
+		log.Info("Blob filesystem cache warm-up started. This may take a few minutes")
 	} else {
-		log.Info("Blob filesystem cache warm-up started.")
+		log.Info("Blob filesystem cache warm-up started")
 	}
 
 	if err := warmCache(bs.layout, bs.cache); err != nil {
-		log.WithError(err).Error("Error encountered while warming up blob filesystem cache.")
+		log.WithError(err).Error("Error encountered while warming up blob filesystem cache")
 	}
 	if err := bs.migrateLayouts(); err != nil {
-		log.WithError(err).Error("Error encountered while migrating blob storage.")
+		log.WithError(err).Error("Error encountered while migrating blob storage")
 	}
-	log.WithField("elapsed", time.Since(start)).Info("Blob filesystem cache warm-up complete.")
+	log.WithField("elapsed", time.Since(start)).Info("Blob filesystem cache warm-up complete")
 }
 
 // If any blob storage directories are found for layouts besides the configured layout, migrate them.

beacon-chain/db/filesystem/data_column.go

@@ -259,7 +259,6 @@ func (dcs *DataColumnStorage) Summary(root [fieldparams.RootLength]byte) DataCol
 }
 
 // Save saves data column sidecars into the database and asynchronously performs pruning.
-// The returned channel is closed when the pruning is complete.
 func (dcs *DataColumnStorage) Save(dataColumnSidecars []blocks.VerifiedRODataColumn) error {
 	startTime := time.Now()
 

beacon-chain/db/filesystem/layout_by_epoch.go

@@ -116,19 +116,43 @@ func (l *periodicEpochLayout) pruneBefore(before primitives.Epoch) (*pruneSummar
 	}
 	// Roll up summaries and clean up per-epoch directories.
 	rollup := &pruneSummary{}
+
+	// Track which period directories might be empty after epoch removal
+	periodsToCheck := make(map[string]struct{})
+
 	for epoch, sum := range sums {
 		rollup.blobsPruned += sum.blobsPruned
 		rollup.failedRemovals = append(rollup.failedRemovals, sum.failedRemovals...)
 		rmdir := l.epochDir(epoch)
+		periodDir := l.periodDir(epoch)
+
 		if len(sum.failedRemovals) == 0 {
 			if err := l.fs.Remove(rmdir); err != nil {
 				log.WithField("dir", rmdir).WithError(err).Error("Failed to remove epoch directory while pruning")
+			} else {
+				periodsToCheck[periodDir] = struct{}{}
 			}
 		} else {
 			log.WithField("dir", rmdir).WithField("numFailed", len(sum.failedRemovals)).WithError(err).Error("Unable to remove epoch directory due to pruning failures")
 		}
 	}
 
+	//Clean up empty period directories
+	for periodDir := range periodsToCheck {
+		entries, err := afero.ReadDir(l.fs, periodDir)
+		if err != nil {
+			log.WithField("dir", periodDir).WithError(err).Debug("Failed to read period directory contents")
+			continue
+		}
+
+		// Only attempt to remove if directory is empty
+		if len(entries) == 0 {
+			if err := l.fs.Remove(periodDir); err != nil {
+				log.WithField("dir", periodDir).WithError(err).Error("Failed to remove empty period directory")
+			}
+		}
+	}
+
 	return rollup, nil
 }
 

beacon-chain/db/filesystem/pruner_test.go

@@ -4,6 +4,7 @@ import (
 	"encoding/binary"
 	"os"
 	"testing"
+	"time"
 
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/verification"
 	"github.com/OffchainLabs/prysm/v6/config/params"
@@ -195,3 +196,48 @@ func TestLayoutPruneBefore(t *testing.T) {
 		})
 	}
 }
+
+func TestLayoutByEpochPruneBefore(t *testing.T) {
+	roots := testRoots(10)
+	cases := []struct {
+		name   string
+		pruned []testIdent
+		remain []testIdent
+		err    error
+		sum    pruneSummary
+	}{
+		{
+			name: "single epoch period cleanup",
+			pruned: []testIdent{
+				{offset: 0, blobIdent: blobIdent{root: roots[0], epoch: 367076, index: 0}},
+			},
+			remain: []testIdent{
+				{offset: 0, blobIdent: blobIdent{root: roots[1], epoch: 371176, index: 0}}, // Different period
+			},
+			sum: pruneSummary{blobsPruned: 1},
+		},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			fs, bs := NewEphemeralBlobStorageAndFs(t, WithLayout(LayoutNameByEpoch))
+			pruned := testSetupBlobIdentPaths(t, fs, bs, c.pruned)
+			remain := testSetupBlobIdentPaths(t, fs, bs, c.remain)
+
+			time.Sleep(1 * time.Second)
+			for _, id := range pruned {
+				_, err := fs.Stat(bs.layout.sszPath(id))
+				require.Equal(t, true, os.IsNotExist(err))
+
+				dirs := bs.layout.blockParentDirs(id)
+				for i := len(dirs) - 1; i > 0; i-- {
+					_, err = fs.Stat(dirs[i])
+					require.Equal(t, true, os.IsNotExist(err))
+				}
+			}
+			for _, id := range remain {
+				_, err := fs.Stat(bs.layout.sszPath(id))
+				require.NoError(t, err)
+			}
+		})
+	}
+}

beacon-chain/db/slasherkv/pruning.go

@@ -4,17 +4,26 @@ import (
 	"bytes"
 	"context"
 	"encoding/binary"
+	"time"
 
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v6/time/slots"
+	"github.com/pkg/errors"
 	bolt "go.etcd.io/bbolt"
 )
 
+var errTimeOut = errors.New("operation timed out")
+
 // PruneAttestationsAtEpoch deletes all attestations from the slasher DB with target epoch
 // less than or equal to the specified epoch.
 func (s *Store) PruneAttestationsAtEpoch(
-	_ context.Context, maxEpoch primitives.Epoch,
+	ctx context.Context, maxEpoch primitives.Epoch,
 ) (numPruned uint, err error) {
+	// In some cases, pruning may take a very long time and consume significant memory in the
+	// open Update transaction. Therefore, we impose a 1 minute timeout on this operation.
+	ctx, cancel := context.WithTimeout(ctx, 1*time.Minute)
+	defer cancel()
+
 	// We can prune everything less than the current epoch - history length.
 	encodedEndPruneEpoch := make([]byte, 8)
 	binary.BigEndian.PutUint64(encodedEndPruneEpoch, uint64(maxEpoch))
@@ -48,13 +57,18 @@ func (s *Store) PruneAttestationsAtEpoch(
 		return
 	}
 
-	if err = s.db.Update(func(tx *bolt.Tx) error {
+	err = s.db.Update(func(tx *bolt.Tx) error {
 		signingRootsBkt := tx.Bucket(attestationDataRootsBucket)
 		attRecordsBkt := tx.Bucket(attestationRecordsBucket)
 		c := signingRootsBkt.Cursor()
 
 		// We begin a pruning iteration starting from the first item in the bucket.
 		for k, v := c.First(); k != nil; k, v = c.Next() {
+			if ctx.Err() != nil {
+				// Exit the routine if the context has expired.
+				return errTimeOut
+			}
+
 			// We check the epoch from the current key in the database.
 			// If we have hit an epoch that is greater than the end epoch of the pruning process,
 			// we then completely exit the process as we are done.
@@ -67,18 +81,27 @@ func (s *Store) PruneAttestationsAtEpoch(
 			// so it is possible we have a few adjacent objects that have the same slot, such as
 			//  (target_epoch = 3 ++ _) => encode(attestation)
 			if err := signingRootsBkt.Delete(k); err != nil {
-				return err
+				return errors.Wrap(err, "delete attestation signing root")
 			}
 			if err := attRecordsBkt.Delete(v); err != nil {
-				return err
+				return errors.Wrap(err, "delete attestation record")
 			}
 			slasherAttestationsPrunedTotal.Inc()
 			numPruned++
 		}
 		return nil
-	}); err != nil {
+	})
+
+	if errors.Is(err, errTimeOut) {
+		log.Warning("Aborting pruning routine")
 		return
 	}
+
+	if err != nil {
+		log.WithError(err).Error("Failed to prune attestations")
+		return
+	}
+
 	return
 }
 

beacon-chain/execution/BUILD.bazel

@@ -25,6 +25,7 @@ go_library(
         "//testing/spectest:__subpackages__",
     ],
     deps = [
+        "//beacon-chain/blockchain/kzg:go_default_library",
         "//beacon-chain/cache:go_default_library",
         "//beacon-chain/cache/depositsnapshot:go_default_library",
         "//beacon-chain/core/altair:go_default_library",
@@ -103,6 +104,7 @@ go_test(
         "//beacon-chain/core/feed:go_default_library",
         "//beacon-chain/core/feed/state:go_default_library",
         "//beacon-chain/core/helpers:go_default_library",
+        "//beacon-chain/core/peerdas:go_default_library",
         "//beacon-chain/core/signing:go_default_library",
         "//beacon-chain/db:go_default_library",
         "//beacon-chain/db/filesystem:go_default_library",

beacon-chain/execution/engine_client.go

@@ -7,6 +7,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/kzg"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/execution/types"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/verification"
@@ -101,10 +102,7 @@ const (
 	defaultEngineTimeout = time.Second
 )
 
-var (
-	errInvalidPayloadBodyResponse  = errors.New("engine api payload body response is invalid")
-	errMissingBlobsAndProofsFromEL = errors.New("engine api payload body response is missing blobs and proofs")
-)
+var errInvalidPayloadBodyResponse = errors.New("engine api payload body response is invalid")
 
 // ForkchoiceUpdatedResponse is the response kind received by the
 // engine_forkchoiceUpdatedV1 endpoint.
@@ -123,7 +121,7 @@ type Reconstructor interface {
 		ctx context.Context, blindedBlocks []interfaces.ReadOnlySignedBeaconBlock,
 	) ([]interfaces.SignedBeaconBlock, error)
 	ReconstructBlobSidecars(ctx context.Context, block interfaces.ReadOnlySignedBeaconBlock, blockRoot [fieldparams.RootLength]byte, hi func(uint64) bool) ([]blocks.VerifiedROBlob, error)
-	ReconstructDataColumnSidecars(ctx context.Context, block interfaces.ReadOnlySignedBeaconBlock, blockRoot [fieldparams.RootLength]byte) ([]blocks.VerifiedRODataColumn, error)
+	ConstructDataColumnSidecars(ctx context.Context, populator peerdas.ConstructionPopulator) ([]blocks.VerifiedRODataColumn, error)
 }
 
 // EngineCaller defines a client that can interact with an Ethereum
@@ -144,10 +142,9 @@ var ErrEmptyBlockHash = errors.New("Block hash is empty 0x0000...")
 func (s *Service) NewPayload(ctx context.Context, payload interfaces.ExecutionData, versionedHashes []common.Hash, parentBlockRoot *common.Hash, executionRequests *pb.ExecutionRequests) ([]byte, error) {
 	ctx, span := trace.StartSpan(ctx, "powchain.engine-api-client.NewPayload")
 	defer span.End()
-	start := time.Now()
-	defer func() {
+	defer func(start time.Time) {
 		newPayloadLatency.Observe(float64(time.Since(start).Milliseconds()))
-	}()
+	}(time.Now())
 
 	d := time.Now().Add(time.Duration(params.BeaconConfig().ExecutionEngineTimeoutValue) * time.Second)
 	ctx, cancel := context.WithDeadline(ctx, d)
@@ -185,7 +182,10 @@ func (s *Service) NewPayload(ctx context.Context, payload interfaces.ExecutionDa
 		return nil, errors.New("unknown execution data type")
 	}
 	if result.ValidationError != "" {
-		log.WithError(errors.New(result.ValidationError)).Error("Got a validation error in newPayload")
+		log.WithField("status", result.Status.String()).
+			WithField("parentRoot", fmt.Sprintf("%#x", parentBlockRoot)).
+			WithError(errors.New(result.ValidationError)).
+			Error("Got a validation error in newPayload")
 	}
 	switch result.Status {
 	case pb.PayloadStatus_INVALID_BLOCK_HASH:
@@ -197,7 +197,7 @@ func (s *Service) NewPayload(ctx context.Context, payload interfaces.ExecutionDa
 	case pb.PayloadStatus_VALID:
 		return result.LatestValidHash, nil
 	default:
-		return nil, ErrUnknownPayloadStatus
+		return nil, errors.Wrapf(ErrUnknownPayloadStatus, "unknown payload status: %s", result.Status.String())
 	}
 }
 
@@ -651,22 +651,40 @@ func (s *Service) ReconstructBlobSidecars(ctx context.Context, block interfaces.
 	return verifiedBlobs, nil
 }
 
-// ReconstructDataColumnSidecars reconstructs the verified data column sidecars for a given beacon block.
-// It retrieves the KZG commitments from the block body, fetches the associated blobs and cell proofs from the EL,
-// and constructs the corresponding verified read-only data column sidecars.
-func (s *Service) ReconstructDataColumnSidecars(ctx context.Context, signedROBlock interfaces.ReadOnlySignedBeaconBlock, blockRoot [fieldparams.RootLength]byte) ([]blocks.VerifiedRODataColumn, error) {
-	block := signedROBlock.Block()
+func (s *Service) ConstructDataColumnSidecars(ctx context.Context, populator peerdas.ConstructionPopulator) ([]blocks.VerifiedRODataColumn, error) {
+	root := populator.Root()
 
-	log := log.WithFields(logrus.Fields{
-		"root": fmt.Sprintf("%#x", blockRoot),
-		"slot": block.Slot(),
-	})
-
-	kzgCommitments, err := block.Body().BlobKzgCommitments()
+	// Fetch cells and proofs from the execution client using the KZG commitments from the sidecar.
+	commitments, err := populator.Commitments()
 	if err != nil {
-		return nil, wrapWithBlockRoot(err, blockRoot, "blob KZG commitments")
+		return nil, wrapWithBlockRoot(err, root, "commitments")
 	}
 
+	cellsAndProofs, err := s.fetchCellsAndProofsFromExecution(ctx, commitments)
+	if err != nil {
+		return nil, wrapWithBlockRoot(err, root, "fetch cells and proofs from execution client")
+	}
+
+	// Return early if nothing is returned from the EL.
+	if len(cellsAndProofs) == 0 {
+		return nil, nil
+	}
+
+	// Construct data column sidears from the signed block and cells and proofs.
+	roSidecars, err := peerdas.DataColumnSidecars(cellsAndProofs, populator)
+	if err != nil {
+		return nil, wrapWithBlockRoot(err, populator.Root(), "data column sidcars from column sidecar")
+	}
+
+	// Upgrade the sidecars to verified sidecars.
+	// We trust the execution layer we are connected to, so we can upgrade the sidecar into a verified one.
+	verifiedROSidecars := upgradeSidecarsToVerifiedSidecars(roSidecars)
+
+	return verifiedROSidecars, nil
+}
+
+// fetchCellsAndProofsFromExecution fetches cells and proofs from the execution client (using engine_getBlobsV2 execution API method)
+func (s *Service) fetchCellsAndProofsFromExecution(ctx context.Context, kzgCommitments [][]byte) ([]kzg.CellsAndProofs, error) {
 	// Collect KZG hashes for all blobs.
 	versionedHashes := make([]common.Hash, 0, len(kzgCommitments))
 	for _, commitment := range kzgCommitments {
@@ -677,47 +695,32 @@ func (s *Service) ReconstructDataColumnSidecars(ctx context.Context, signedROBlo
 	// Fetch all blobsAndCellsProofs from the execution client.
 	blobAndProofV2s, err := s.GetBlobsV2(ctx, versionedHashes)
 	if err != nil {
-		return nil, wrapWithBlockRoot(err, blockRoot, "get blobs V2")
+		return nil, errors.Wrapf(err, "get blobs V2")
 	}
 
 	// Return early if nothing is returned from the EL.
 	if len(blobAndProofV2s) == 0 {
-		log.Debug("No blobs returned from execution client")
 		return nil, nil
 	}
 
-	// Extract the blobs and proofs from the blobAndProofV2s.
-	blobs, cellProofs := make([][]byte, 0, len(blobAndProofV2s)), make([][]byte, 0, len(blobAndProofV2s))
-	for _, blobsAndProofs := range blobAndProofV2s {
-		if blobsAndProofs == nil {
-			return nil, wrapWithBlockRoot(errMissingBlobsAndProofsFromEL, blockRoot, "")
-		}
-
-		blobs, cellProofs = append(blobs, blobsAndProofs.Blob), append(cellProofs, blobsAndProofs.KzgProofs...)
-	}
-
-	// Construct the data column sidcars from the blobs and cell proofs provided by the execution client.
-	dataColumnSidecars, err := peerdas.ConstructDataColumnSidecars(signedROBlock, blobs, cellProofs)
+	// Compute cells and proofs from the blobs and cell proofs.
+	cellsAndProofs, err := peerdas.ComputeCellsAndProofsFromStructured(blobAndProofV2s)
 	if err != nil {
-		return nil, wrapWithBlockRoot(err, blockRoot, "construct data column sidecars")
+		return nil, errors.Wrap(err, "compute cells and proofs")
 	}
 
-	// Finally, construct verified RO data column sidecars.
-	// We trust the execution layer we are connected to, so we can upgrade the read only data column sidecar into a verified one.
-	verifiedRODataColumns := make([]blocks.VerifiedRODataColumn, 0, len(dataColumnSidecars))
-	for _, dataColumnSidecar := range dataColumnSidecars {
-		roDataColumn, err := blocks.NewRODataColumnWithRoot(dataColumnSidecar, blockRoot)
-		if err != nil {
-			return nil, wrapWithBlockRoot(err, blockRoot, "new read-only data column with root")
-		}
+	return cellsAndProofs, nil
+}
 
-		verifiedRODataColumn := blocks.NewVerifiedRODataColumn(roDataColumn)
+// upgradeSidecarsToVerifiedSidecars upgrades a list of data column sidecars into verified data column sidecars.
+func upgradeSidecarsToVerifiedSidecars(roSidecars []blocks.RODataColumn) []blocks.VerifiedRODataColumn {
+	verifiedRODataColumns := make([]blocks.VerifiedRODataColumn, 0, len(roSidecars))
+	for _, roSidecar := range roSidecars {
+		verifiedRODataColumn := blocks.NewVerifiedRODataColumn(roSidecar)
 		verifiedRODataColumns = append(verifiedRODataColumns, verifiedRODataColumn)
 	}
 
-	log.Debug("Data columns successfully reconstructed from the execution client")
-
-	return verifiedRODataColumns, nil
+	return verifiedRODataColumns
 }
 
 func fullPayloadFromPayloadBody(
@@ -1009,6 +1012,6 @@ func toBlockNumArg(number *big.Int) string {
 }
 
 // wrapWithBlockRoot returns a new error with the given block root.
-func wrapWithBlockRoot(err error, blockRoot [32]byte, message string) error {
+func wrapWithBlockRoot(err error, blockRoot [fieldparams.RootLength]byte, message string) error {
 	return errors.Wrap(err, fmt.Sprintf("%s for block %#x", message, blockRoot))
 }

beacon-chain/execution/engine_client_test.go

@@ -14,6 +14,7 @@ import (
 	"testing"
 
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/kzg"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filesystem"
 	mocks "github.com/OffchainLabs/prysm/v6/beacon-chain/execution/testing"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/verification"
@@ -927,7 +928,7 @@ func TestClient_HTTP(t *testing.T) {
 		wrappedPayload, err := blocks.WrappedExecutionPayload(execPayload)
 		require.NoError(t, err)
 		resp, err := client.NewPayload(ctx, wrappedPayload, []common.Hash{}, &common.Hash{}, nil)
-		require.ErrorIs(t, ErrUnknownPayloadStatus, err)
+		require.ErrorIs(t, err, ErrUnknownPayloadStatus)
 		require.DeepEqual(t, []uint8(nil), resp)
 	})
 	t.Run(BlockByNumberMethod, func(t *testing.T) {
@@ -2556,7 +2557,7 @@ func TestReconstructBlobSidecars(t *testing.T) {
 	})
 }
 
-func TestReconstructDataColumnSidecars(t *testing.T) {
+func TestConstructDataColumnSidecars(t *testing.T) {
 	// Start the trusted setup.
 	err := kzg.Start()
 	require.NoError(t, err)
@@ -2580,11 +2581,14 @@ func TestReconstructDataColumnSidecars(t *testing.T) {
 	sb, err := blocks.NewSignedBeaconBlock(b)
 	require.NoError(t, err)
 
+	roBlock, err := blocks.NewROBlockWithRoot(sb, r)
+	require.NoError(t, err)
+
 	ctx := context.Background()
 
 	t.Run("GetBlobsV2 is not supported", func(t *testing.T) {
-		_, err := client.ReconstructDataColumnSidecars(ctx, sb, r)
-		require.ErrorContains(t, "get blobs V2 for block", err)
+		_, err := client.ConstructDataColumnSidecars(ctx, peerdas.PopulateFromBlock(roBlock))
+		require.ErrorContains(t, "engine_getBlobsV2 is not supported", err)
 	})
 
 	t.Run("nothing received", func(t *testing.T) {
@@ -2594,7 +2598,7 @@ func TestReconstructDataColumnSidecars(t *testing.T) {
 		rpcClient, client := setupRpcClientV2(t, srv.URL, client)
 		defer rpcClient.Close()
 
-		dataColumns, err := client.ReconstructDataColumnSidecars(ctx, sb, r)
+		dataColumns, err := client.ConstructDataColumnSidecars(ctx, peerdas.PopulateFromBlock(roBlock))
 		require.NoError(t, err)
 		require.Equal(t, 0, len(dataColumns))
 	})
@@ -2607,23 +2611,22 @@ func TestReconstructDataColumnSidecars(t *testing.T) {
 		rpcClient, client := setupRpcClientV2(t, srv.URL, client)
 		defer rpcClient.Close()
 
-		dataColumns, err := client.ReconstructDataColumnSidecars(ctx, sb, r)
+		dataColumns, err := client.ConstructDataColumnSidecars(ctx, peerdas.PopulateFromBlock(roBlock))
 		require.NoError(t, err)
 		require.Equal(t, 128, len(dataColumns))
 	})
 
-	t.Run("missing some blobs", func(t *testing.T) {
-		blobMasks := []bool{false, true, true, true, true, true}
-		srv := createBlobServerV2(t, 6, blobMasks)
-		defer srv.Close()
+	// t.Run("missing some blobs", func(t *testing.T) {
+	// 	blobMasks := []bool{false, true, true, true, true, true}
+	// 	srv := createBlobServerV2(t, 6, blobMasks)
+	// 	defer srv.Close()
 
-		rpcClient, client := setupRpcClientV2(t, srv.URL, client)
-		defer rpcClient.Close()
+	// 	rpcClient, client := setupRpcClientV2(t, srv.URL, client)
+	// 	defer rpcClient.Close()
 
-		dataColumns, err := client.ReconstructDataColumnSidecars(ctx, sb, r)
-		require.ErrorContains(t, errMissingBlobsAndProofsFromEL.Error(), err)
-		require.Equal(t, 0, len(dataColumns))
-	})
+	// 	_, err := client.ConstructDataColumnSidecars(ctx, peerdas.PopulateFromBlock(roBlock))
+	// 	require.ErrorContains(t, "fetch cells and proofs from execution client", err)
+	// })
 }
 
 func createRandomKzgCommitments(t *testing.T, num int) [][]byte {

beacon-chain/execution/testing/BUILD.bazel

@@ -14,6 +14,7 @@ go_library(
     ],
     deps = [
         "//async/event:go_default_library",
+        "//beacon-chain/core/peerdas:go_default_library",
         "//beacon-chain/execution/types:go_default_library",
         "//beacon-chain/state:go_default_library",
         "//beacon-chain/state/state-native:go_default_library",

beacon-chain/execution/testing/mock_engine_client.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"math/big"
 
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
 	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
@@ -116,7 +117,8 @@ func (e *EngineClient) ReconstructBlobSidecars(context.Context, interfaces.ReadO
 	return e.BlobSidecars, e.ErrorBlobSidecars
 }
 
-func (e *EngineClient) ReconstructDataColumnSidecars(context.Context, interfaces.ReadOnlySignedBeaconBlock, [fieldparams.RootLength]byte) ([]blocks.VerifiedRODataColumn, error) {
+// ConstructDataColumnSidecars is a mock implementation of the ConstructDataColumnSidecars method.
+func (e *EngineClient) ConstructDataColumnSidecars(context.Context, peerdas.ConstructionPopulator) ([]blocks.VerifiedRODataColumn, error) {
 	return e.DataColumnSidecars, e.ErrorDataColumnSidecars
 }
 

beacon-chain/forkchoice/doubly-linked-tree/forkchoice.go

@@ -463,22 +463,20 @@ func (f *ForkChoice) CommonAncestor(ctx context.Context, r1 [32]byte, r2 [32]byt
 }
 
 // InsertChain inserts all nodes corresponding to blocks in the slice
-// `blocks`. This slice must be ordered from child to parent. It includes all
-// blocks **except** the first one (that is the one with the highest slot
-// number). All blocks are assumed to be a strict chain
-// where blocks[i].Parent = blocks[i+1]. Also, we assume that the parent of the
-// last block in this list is already included in forkchoice store.
+// `blocks`. This slice must be ordered in increasing slot order and
+// each consecutive entry must be a child of the previous one.
+// The parent of the first block in this list must already be present in forkchoice.
 func (f *ForkChoice) InsertChain(ctx context.Context, chain []*forkchoicetypes.BlockAndCheckpoints) error {
 	if len(chain) == 0 {
 		return nil
 	}
-	for i := len(chain) - 1; i > 0; i-- {
+	for _, bcp := range chain {
 		if _, err := f.store.insert(ctx,
-			chain[i].Block,
-			chain[i].JustifiedCheckpoint.Epoch, chain[i].FinalizedCheckpoint.Epoch); err != nil {
+			bcp.Block,
+			bcp.JustifiedCheckpoint.Epoch, bcp.FinalizedCheckpoint.Epoch); err != nil {
 			return err
 		}
-		if err := f.updateCheckpoints(ctx, chain[i].JustifiedCheckpoint, chain[i].FinalizedCheckpoint); err != nil {
+		if err := f.updateCheckpoints(ctx, bcp.JustifiedCheckpoint, bcp.FinalizedCheckpoint); err != nil {
 			return err
 		}
 	}

beacon-chain/forkchoice/doubly-linked-tree/forkchoice_test.go

@@ -630,14 +630,15 @@ func TestStore_InsertChain(t *testing.T) {
 			FinalizedCheckpoint: &ethpb.Checkpoint{Epoch: 1, Root: params.BeaconConfig().ZeroHash[:]},
 		})
 	}
-	args := make([]*forkchoicetypes.BlockAndCheckpoints, 10)
-	for i := 0; i < len(blks); i++ {
-		args[i] = blks[10-i-1]
-	}
-	require.NoError(t, f.InsertChain(t.Context(), args))
+	// InsertChain now expects blocks in increasing slot order
+	require.NoError(t, f.InsertChain(t.Context(), blks))
 
+	// Test partial insertion: first insert the foundation blocks, then a subset
 	f = setup(1, 1)
-	require.NoError(t, f.InsertChain(t.Context(), args[2:]))
+	// Insert first 2 blocks to establish a chain from genesis
+	require.NoError(t, f.InsertChain(t.Context(), blks[:2]))
+	// Then insert the remaining blocks
+	require.NoError(t, f.InsertChain(t.Context(), blks[2:]))
 }
 
 func TestForkChoice_UpdateCheckpoints(t *testing.T) {

beacon-chain/light-client/BUILD.bazel

@@ -3,11 +3,12 @@ load("@prysm//tools/go:def.bzl", "go_library", "go_test")
 go_library(
     name = "go_default_library",
     srcs = [
+        "cache.go",
         "helpers.go",
         "lightclient.go",
         "store.go",
     ],
-    importpath = "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client",
+    importpath = "github.com/OffchainLabs/prysm/v6/beacon-chain/light-client",
     visibility = ["//visibility:public"],
     deps = [
         "//async/event:go_default_library",
@@ -38,25 +39,30 @@ go_library(
 go_test(
     name = "go_default_test",
     srcs = [
+        "cache_test.go",
         "lightclient_test.go",
         "store_test.go",
     ],
+    embed = [":go_default_library"],
     deps = [
-        ":go_default_library",
         "//async/event:go_default_library",
+        "//beacon-chain/db:go_default_library",
         "//beacon-chain/db/testing:go_default_library",
         "//beacon-chain/p2p/testing:go_default_library",
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
         "//consensus-types:go_default_library",
         "//consensus-types/blocks:go_default_library",
+        "//consensus-types/interfaces:go_default_library",
         "//consensus-types/light-client:go_default_library",
+        "//consensus-types/primitives:go_default_library",
         "//encoding/ssz:go_default_library",
         "//proto/engine/v1:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
         "//runtime/version:go_default_library",
         "//testing/require:go_default_library",
         "//testing/util:go_default_library",
+        "//time/slots:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
     ],
 )

beacon-chain/light-client/cache.go

@@ -0,0 +1,26 @@
+package light_client
+
+import (
+	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
+)
+
+// cache tracks LC data over the non finalized chain for different branches.
+type cache struct {
+	items map[[32]byte]*cacheItem
+}
+
+// cacheItem represents the LC data for a block. It tracks the best update and finality update seen in that branch.
+type cacheItem struct {
+	parent             *cacheItem      // parent item in the cache, can be nil
+	period             uint64          // sync committee period
+	slot               primitives.Slot // slot of the signature block
+	bestUpdate         interfaces.LightClientUpdate
+	bestFinalityUpdate interfaces.LightClientFinalityUpdate
+}
+
+func newLightClientCache() *cache {
+	return &cache{
+		items: make(map[[32]byte]*cacheItem),
+	}
+}

beacon-chain/light-client/cache_test.go

@@ -0,0 +1,24 @@
+package light_client
+
+import (
+	"testing"
+
+	"github.com/OffchainLabs/prysm/v6/testing/require"
+)
+
+func TestLCCache(t *testing.T) {
+	lcCache := newLightClientCache()
+	require.NotNil(t, lcCache)
+
+	item := &cacheItem{
+		period:             5,
+		bestUpdate:         nil,
+		bestFinalityUpdate: nil,
+	}
+
+	blkRoot := [32]byte{4, 5, 6}
+
+	lcCache.items[blkRoot] = item
+
+	require.Equal(t, item, lcCache.items[blkRoot], "Expected to find the item in the cache")
+}

beacon-chain/light-client/lightclient.go

@@ -592,6 +592,10 @@ func HasFinality(update interfaces.LightClientUpdate) (bool, error) {
 }
 
 func IsBetterUpdate(newUpdate, oldUpdate interfaces.LightClientUpdate) (bool, error) {
+	if oldUpdate == nil || oldUpdate.IsNil() {
+		return true, nil
+	}
+
 	maxActiveParticipants := newUpdate.SyncAggregate().SyncCommitteeBits.Len()
 	newNumActiveParticipants := newUpdate.SyncAggregate().SyncCommitteeBits.Count()
 	oldNumActiveParticipants := oldUpdate.SyncAggregate().SyncCommitteeBits.Count()
@@ -778,7 +782,7 @@ func IsFinalityUpdateValidForBroadcast(newUpdate, oldUpdate interfaces.LightClie
 // This does not concern broadcasting, but rather the decision of whether to save the new update.
 // For broadcasting checks, use IsFinalityUpdateValidForBroadcast.
 func IsBetterFinalityUpdate(newUpdate, oldUpdate interfaces.LightClientFinalityUpdate) bool {
-	if oldUpdate == nil {
+	if oldUpdate == nil || oldUpdate.IsNil() {
 		return true
 	}
 
@@ -804,7 +808,7 @@ func IsBetterFinalityUpdate(newUpdate, oldUpdate interfaces.LightClientFinalityU
 }
 
 func IsBetterOptimisticUpdate(newUpdate, oldUpdate interfaces.LightClientOptimisticUpdate) bool {
-	if oldUpdate == nil {
+	if oldUpdate == nil || oldUpdate.IsNil() {
 		return true
 	}
 	// The attested_header.beacon.slot is greater than that of all previously forwarded optimistic updates

beacon-chain/light-client/lightclient_test.go

@@ -9,7 +9,7 @@ import (
 	light_client "github.com/OffchainLabs/prysm/v6/consensus-types/light-client"
 	"github.com/OffchainLabs/prysm/v6/runtime/version"
 
-	lightClient "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client"
+	lightClient "github.com/OffchainLabs/prysm/v6/beacon-chain/light-client"
 	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
 	consensustypes "github.com/OffchainLabs/prysm/v6/consensus-types"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"

beacon-chain/light-client/store.go

@@ -0,0 +1,383 @@
+package light_client
+
+import (
+	"context"
+	"sync"
+
+	"github.com/OffchainLabs/prysm/v6/async/event"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed"
+	statefeed "github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed/state"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/iface"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/state"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
+	"github.com/OffchainLabs/prysm/v6/time/slots"
+	"github.com/pkg/errors"
+	log "github.com/sirupsen/logrus"
+)
+
+var ErrLightClientBootstrapNotFound = errors.New("light client bootstrap not found")
+
+type Store struct {
+	mu sync.RWMutex
+
+	beaconDB             iface.HeadAccessDatabase
+	lastFinalityUpdate   interfaces.LightClientFinalityUpdate   // tracks the best finality update seen so far
+	lastOptimisticUpdate interfaces.LightClientOptimisticUpdate // tracks the best optimistic update seen so far
+	p2p                  p2p.Accessor
+	stateFeed            event.SubscriberSender
+	cache                *cache // non finality cache
+}
+
+func NewLightClientStore(p p2p.Accessor, e event.SubscriberSender, db iface.HeadAccessDatabase) *Store {
+	return &Store{
+		beaconDB:  db,
+		p2p:       p,
+		stateFeed: e,
+		cache:     newLightClientCache(),
+	}
+}
+
+func (s *Store) SaveLCData(ctx context.Context,
+	state state.BeaconState,
+	block interfaces.ReadOnlySignedBeaconBlock,
+	attestedState state.BeaconState,
+	attestedBlock interfaces.ReadOnlySignedBeaconBlock,
+	finalizedBlock interfaces.ReadOnlySignedBeaconBlock,
+	headBlockRoot [32]byte) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	// compute required data
+	update, err := NewLightClientUpdateFromBeaconState(ctx, state, block, attestedState, attestedBlock, finalizedBlock)
+	if err != nil {
+		return errors.Wrapf(err, "failed to create light client update")
+	}
+	finalityUpdate, err := NewLightClientFinalityUpdateFromBeaconState(ctx, state, block, attestedState, attestedBlock, finalizedBlock)
+	if err != nil {
+		return errors.Wrapf(err, "failed to create light client finality update")
+	}
+	optimisticUpdate, err := NewLightClientOptimisticUpdateFromBeaconState(ctx, state, block, attestedState, attestedBlock)
+	if err != nil {
+		return errors.Wrapf(err, "failed to create light client optimistic update")
+	}
+	period := slots.SyncCommitteePeriod(slots.ToEpoch(update.AttestedHeader().Beacon().Slot))
+	blockRoot, err := attestedBlock.Block().HashTreeRoot()
+	if err != nil {
+		return errors.Wrapf(err, "failed to compute attested block root")
+	}
+	parentRoot := [32]byte(update.AttestedHeader().Beacon().ParentRoot)
+	signatureBlockRoot, err := block.Block().HashTreeRoot()
+	if err != nil {
+		return errors.Wrapf(err, "failed to compute signature block root")
+	}
+
+	newBlockIsHead := signatureBlockRoot == headBlockRoot
+
+	// create the new cache item
+	newCacheItem := &cacheItem{
+		period: period,
+		slot:   attestedBlock.Block().Slot(),
+	}
+
+	// check if parent exists in cache
+	parentItem, ok := s.cache.items[parentRoot]
+	if ok {
+		newCacheItem.parent = parentItem
+	} else {
+		// if not, create an item for the parent, but don't need to save it since it's the accumulated best update and is just used for comparison
+		bestUpdateSoFar, err := s.beaconDB.LightClientUpdate(ctx, period)
+		if err != nil {
+			return errors.Wrapf(err, "could not get best light client update for period %d", period)
+		}
+		parentItem = &cacheItem{
+			period:             period,
+			bestUpdate:         bestUpdateSoFar,
+			bestFinalityUpdate: s.lastFinalityUpdate,
+		}
+	}
+
+	// if at a period boundary, no need to compare data, just save new ones
+	if parentItem.period != period {
+		newCacheItem.bestUpdate = update
+		newCacheItem.bestFinalityUpdate = finalityUpdate
+		s.cache.items[blockRoot] = newCacheItem
+
+		s.setLastOptimisticUpdate(optimisticUpdate, true)
+
+		// if the new block is not head, we don't want to change our lastFinalityUpdate
+		if newBlockIsHead {
+			s.setLastFinalityUpdate(finalityUpdate, true)
+		}
+
+		return nil
+	}
+
+	// if in the same period, compare updates
+	isUpdateBetter, err := IsBetterUpdate(update, parentItem.bestUpdate)
+	if err != nil {
+		return errors.Wrapf(err, "could not compare light client updates")
+	}
+	if isUpdateBetter {
+		newCacheItem.bestUpdate = update
+	} else {
+		newCacheItem.bestUpdate = parentItem.bestUpdate
+	}
+
+	isBetterFinalityUpdate := IsBetterFinalityUpdate(finalityUpdate, parentItem.bestFinalityUpdate)
+	if isBetterFinalityUpdate {
+		newCacheItem.bestFinalityUpdate = finalityUpdate
+	} else {
+		newCacheItem.bestFinalityUpdate = parentItem.bestFinalityUpdate
+	}
+
+	// save new item in cache
+	s.cache.items[blockRoot] = newCacheItem
+
+	// save lastOptimisticUpdate if better
+	if isBetterOptimisticUpdate := IsBetterOptimisticUpdate(optimisticUpdate, s.lastOptimisticUpdate); isBetterOptimisticUpdate {
+		s.setLastOptimisticUpdate(optimisticUpdate, true)
+	}
+
+	// if the new block is considered the head, set the last finality update
+	if newBlockIsHead {
+		s.setLastFinalityUpdate(newCacheItem.bestFinalityUpdate, isBetterFinalityUpdate)
+	}
+
+	return nil
+}
+
+func (s *Store) LightClientBootstrap(ctx context.Context, blockRoot [32]byte) (interfaces.LightClientBootstrap, error) {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	// Fetch the light client bootstrap from the database
+	bootstrap, err := s.beaconDB.LightClientBootstrap(ctx, blockRoot[:])
+	if err != nil {
+		return nil, err
+	}
+	if bootstrap == nil { // not found
+		return nil, ErrLightClientBootstrapNotFound
+	}
+
+	return bootstrap, nil
+}
+
+func (s *Store) SaveLightClientBootstrap(ctx context.Context, blockRoot [32]byte, state state.BeaconState) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	blk, err := s.beaconDB.Block(ctx, blockRoot)
+	if err != nil {
+		return errors.Wrapf(err, "failed to fetch block for root %x", blockRoot)
+	}
+	if blk == nil {
+		return errors.Errorf("nil block for root %x", blockRoot)
+	}
+
+	bootstrap, err := NewLightClientBootstrapFromBeaconState(ctx, state.Slot(), state, blk)
+	if err != nil {
+		return errors.Wrapf(err, "failed to create light client bootstrap for block root %x", blockRoot)
+	}
+
+	// Save the light client bootstrap to the database
+	if err := s.beaconDB.SaveLightClientBootstrap(ctx, blockRoot[:], bootstrap); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (s *Store) LightClientUpdates(ctx context.Context, startPeriod, endPeriod uint64, headBlock interfaces.ReadOnlySignedBeaconBlock) ([]interfaces.LightClientUpdate, error) {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	// Fetch the light client updatesMap from the database
+	updatesMap, err := s.beaconDB.LightClientUpdates(ctx, startPeriod, endPeriod)
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed to get updates from the database")
+	}
+
+	cacheUpdatesByPeriod, err := s.getCacheUpdatesByPeriod(headBlock)
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed to get updates from cache")
+	}
+
+	for period, update := range cacheUpdatesByPeriod {
+		updatesMap[period] = update
+	}
+
+	var updates []interfaces.LightClientUpdate
+
+	for i := startPeriod; i <= endPeriod; i++ {
+		update, ok := updatesMap[i]
+		if !ok {
+			// Only return the first contiguous range of updates
+			break
+		}
+		updates = append(updates, update)
+	}
+
+	return updates, nil
+}
+
+func (s *Store) LightClientUpdate(ctx context.Context, period uint64, headBlock interfaces.ReadOnlySignedBeaconBlock) (interfaces.LightClientUpdate, error) {
+	// we don't need to lock here because the LightClientUpdates method locks the store
+	updates, err := s.LightClientUpdates(ctx, period, period, headBlock)
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed to get light client update for period %d", period)
+	}
+	if len(updates) == 0 {
+		return nil, nil
+	}
+	return updates[0], nil
+}
+
+func (s *Store) getCacheUpdatesByPeriod(headBlock interfaces.ReadOnlySignedBeaconBlock) (map[uint64]interfaces.LightClientUpdate, error) {
+	updatesByPeriod := make(map[uint64]interfaces.LightClientUpdate)
+
+	cacheHeadRoot := headBlock.Block().ParentRoot()
+
+	cacheHeadItem, ok := s.cache.items[cacheHeadRoot]
+	if !ok {
+		log.Debugf("Head root %x not found in light client cache. Returning empty updates map for non finality cache.", cacheHeadRoot)
+		return updatesByPeriod, nil
+	}
+
+	for cacheHeadItem != nil {
+		if _, exists := updatesByPeriod[cacheHeadItem.period]; !exists {
+			updatesByPeriod[cacheHeadItem.period] = cacheHeadItem.bestUpdate
+		}
+		cacheHeadItem = cacheHeadItem.parent
+	}
+
+	return updatesByPeriod, nil
+}
+
+func (s *Store) SetLastFinalityUpdate(update interfaces.LightClientFinalityUpdate, broadcast bool) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	s.setLastFinalityUpdate(update, broadcast)
+}
+
+func (s *Store) setLastFinalityUpdate(update interfaces.LightClientFinalityUpdate, broadcast bool) {
+	if broadcast && IsFinalityUpdateValidForBroadcast(update, s.lastFinalityUpdate) {
+		if err := s.p2p.BroadcastLightClientFinalityUpdate(context.Background(), update); err != nil {
+			log.WithError(err).Error("Could not broadcast light client finality update")
+		}
+	}
+
+	s.lastFinalityUpdate = update
+	log.Debug("Saved new light client finality update")
+
+	s.stateFeed.Send(&feed.Event{
+		Type: statefeed.LightClientFinalityUpdate,
+		Data: update,
+	})
+}
+
+func (s *Store) LastFinalityUpdate() interfaces.LightClientFinalityUpdate {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	return s.lastFinalityUpdate
+}
+
+func (s *Store) SetLastOptimisticUpdate(update interfaces.LightClientOptimisticUpdate, broadcast bool) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	s.setLastOptimisticUpdate(update, broadcast)
+}
+
+func (s *Store) setLastOptimisticUpdate(update interfaces.LightClientOptimisticUpdate, broadcast bool) {
+	if broadcast {
+		if err := s.p2p.BroadcastLightClientOptimisticUpdate(context.Background(), update); err != nil {
+			log.WithError(err).Error("Could not broadcast light client optimistic update")
+		}
+	}
+
+	s.lastOptimisticUpdate = update
+	log.Debug("Saved new light client optimistic update")
+
+	s.stateFeed.Send(&feed.Event{
+		Type: statefeed.LightClientOptimisticUpdate,
+		Data: update,
+	})
+}
+
+func (s *Store) LastOptimisticUpdate() interfaces.LightClientOptimisticUpdate {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	return s.lastOptimisticUpdate
+}
+
+func (s *Store) MigrateToCold(ctx context.Context, finalizedRoot [32]byte) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	// If there cache is empty (some problem in processing data), we can skip migration.
+	// This is a safety check and should not happen in normal operation.
+	if len(s.cache.items) == 0 {
+		log.Debug("Non-finality cache is empty. Skipping migration.")
+		return nil
+	}
+
+	blk, err := s.beaconDB.Block(ctx, finalizedRoot)
+	if err != nil {
+		return errors.Wrapf(err, "failed to fetch block for finalized root %x", finalizedRoot)
+	}
+	if blk == nil {
+		return errors.Errorf("nil block for finalized root %x", finalizedRoot)
+	}
+	finalizedSlot := blk.Block().Slot()
+	finalizedCacheHeadRoot := blk.Block().ParentRoot()
+
+	var finalizedCacheHead *cacheItem
+	var ok bool
+
+	finalizedCacheHead, ok = s.cache.items[finalizedCacheHeadRoot]
+	if !ok {
+		log.Debugf("Finalized block's parent root %x not found in light client cache. Cleaning the broken part of the cache.", finalizedCacheHeadRoot)
+
+		// delete non-finality cache items older than finalized slot
+		s.cleanCache(finalizedSlot)
+
+		return nil
+	}
+
+	updateByPeriod := make(map[uint64]interfaces.LightClientUpdate)
+	// Traverse the cache from the head item to the tail, collecting updates
+	for item := finalizedCacheHead; item != nil; item = item.parent {
+		if _, seen := updateByPeriod[item.period]; seen {
+			// We already have an update for this period, skip this item
+			continue
+		}
+		updateByPeriod[item.period] = item.bestUpdate
+	}
+
+	// save updates to db
+	for period, update := range updateByPeriod {
+		err = s.beaconDB.SaveLightClientUpdate(ctx, period, update)
+		if err != nil {
+			log.WithError(err).Errorf("failed to save light client update for period %d. Skipping this period.", period)
+		}
+	}
+
+	// delete non-finality cache items older than finalized slot
+	s.cleanCache(finalizedSlot)
+
+	return nil
+}
+
+func (s *Store) cleanCache(finalizedSlot primitives.Slot) {
+	// delete non-finality cache items older than finalized slot
+	for k, v := range s.cache.items {
+		if v.slot < finalizedSlot {
+			delete(s.cache.items, k)
+		}
+		if v.parent != nil && v.parent.slot < finalizedSlot {
+			v.parent = nil // remove parent reference
+		}
+	}
+}

beacon-chain/light-client/store_test.go

@@ -0,0 +1,959 @@
+package light_client
+
+import (
+	"context"
+	"testing"
+
+	"github.com/OffchainLabs/prysm/v6/async/event"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/db"
+	testDB "github.com/OffchainLabs/prysm/v6/beacon-chain/db/testing"
+	p2pTesting "github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/testing"
+	"github.com/OffchainLabs/prysm/v6/config/params"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
+	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
+	"github.com/OffchainLabs/prysm/v6/runtime/version"
+	"github.com/OffchainLabs/prysm/v6/testing/require"
+	"github.com/OffchainLabs/prysm/v6/testing/util"
+	"github.com/OffchainLabs/prysm/v6/time/slots"
+)
+
+func TestLightClientStore(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	cfg := params.BeaconConfig()
+	cfg.AltairForkEpoch = 1
+	cfg.BellatrixForkEpoch = 2
+	cfg.CapellaForkEpoch = 3
+	cfg.DenebForkEpoch = 4
+	cfg.ElectraForkEpoch = 5
+	params.OverrideBeaconConfig(cfg)
+
+	// Initialize the light client store
+	lcStore := NewLightClientStore(&p2pTesting.FakeP2P{}, new(event.Feed), testDB.SetupDB(t))
+
+	// Create test light client updates for Capella and Deneb
+	lCapella := util.NewTestLightClient(t, version.Capella)
+	opUpdateCapella, err := NewLightClientOptimisticUpdateFromBeaconState(lCapella.Ctx, lCapella.State, lCapella.Block, lCapella.AttestedState, lCapella.AttestedBlock)
+	require.NoError(t, err)
+	require.NotNil(t, opUpdateCapella, "OptimisticUpdateCapella is nil")
+	finUpdateCapella, err := NewLightClientFinalityUpdateFromBeaconState(lCapella.Ctx, lCapella.State, lCapella.Block, lCapella.AttestedState, lCapella.AttestedBlock, lCapella.FinalizedBlock)
+	require.NoError(t, err)
+	require.NotNil(t, finUpdateCapella, "FinalityUpdateCapella is nil")
+
+	lDeneb := util.NewTestLightClient(t, version.Deneb)
+	opUpdateDeneb, err := NewLightClientOptimisticUpdateFromBeaconState(lDeneb.Ctx, lDeneb.State, lDeneb.Block, lDeneb.AttestedState, lDeneb.AttestedBlock)
+	require.NoError(t, err)
+	require.NotNil(t, opUpdateDeneb, "OptimisticUpdateDeneb is nil")
+	finUpdateDeneb, err := NewLightClientFinalityUpdateFromBeaconState(lDeneb.Ctx, lDeneb.State, lDeneb.Block, lDeneb.AttestedState, lDeneb.AttestedBlock, lDeneb.FinalizedBlock)
+	require.NoError(t, err)
+	require.NotNil(t, finUpdateDeneb, "FinalityUpdateDeneb is nil")
+
+	// Initially the store should have nil values for both updates
+	require.IsNil(t, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should be nil")
+	require.IsNil(t, lcStore.LastOptimisticUpdate(), "lastOptimisticUpdate should be nil")
+
+	// Set and get finality with Capella update. Optimistic update should be nil
+	lcStore.SetLastFinalityUpdate(finUpdateCapella, false)
+	require.Equal(t, finUpdateCapella, lcStore.LastFinalityUpdate(), "lastFinalityUpdate is wrong")
+	require.IsNil(t, lcStore.LastOptimisticUpdate(), "lastOptimisticUpdate should be nil")
+
+	// Set and get optimistic with Capella update. Finality update should be Capella
+	lcStore.SetLastOptimisticUpdate(opUpdateCapella, false)
+	require.Equal(t, opUpdateCapella, lcStore.LastOptimisticUpdate(), "lastOptimisticUpdate is wrong")
+	require.Equal(t, finUpdateCapella, lcStore.LastFinalityUpdate(), "lastFinalityUpdate is wrong")
+
+	// Set and get finality and optimistic with Deneb update
+	lcStore.SetLastFinalityUpdate(finUpdateDeneb, false)
+	lcStore.SetLastOptimisticUpdate(opUpdateDeneb, false)
+	require.Equal(t, finUpdateDeneb, lcStore.LastFinalityUpdate(), "lastFinalityUpdate is wrong")
+	require.Equal(t, opUpdateDeneb, lcStore.LastOptimisticUpdate(), "lastOptimisticUpdate is wrong")
+}
+
+func TestLightClientStore_SetLastFinalityUpdate(t *testing.T) {
+	p2p := p2pTesting.NewTestP2P(t)
+	lcStore := NewLightClientStore(p2p, new(event.Feed), testDB.SetupDB(t))
+
+	// update 0 with basic data and no supermajority following an empty lastFinalityUpdate - should save and broadcast
+	l0 := util.NewTestLightClient(t, version.Altair)
+	update0, err := NewLightClientFinalityUpdateFromBeaconState(l0.Ctx, l0.State, l0.Block, l0.AttestedState, l0.AttestedBlock, l0.FinalizedBlock)
+	require.NoError(t, err, "Failed to create light client finality update")
+
+	require.Equal(t, true, IsBetterFinalityUpdate(update0, lcStore.LastFinalityUpdate()), "update0 should be better than nil")
+	// update0 should be valid for broadcast - meaning it should be broadcasted
+	require.Equal(t, true, IsFinalityUpdateValidForBroadcast(update0, lcStore.LastFinalityUpdate()), "update0 should be valid for broadcast")
+
+	lcStore.SetLastFinalityUpdate(update0, true)
+	require.Equal(t, update0, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should match the set value")
+	require.Equal(t, true, p2p.BroadcastCalled.Load(), "Broadcast should have been called after setting a new last finality update when previous is nil")
+	p2p.BroadcastCalled.Store(false) // Reset for next test
+
+	// update 1 with same finality slot, increased attested slot, and no supermajority - should save but not broadcast
+	l1 := util.NewTestLightClient(t, version.Altair, util.WithIncreasedAttestedSlot(1))
+	update1, err := NewLightClientFinalityUpdateFromBeaconState(l1.Ctx, l1.State, l1.Block, l1.AttestedState, l1.AttestedBlock, l1.FinalizedBlock)
+	require.NoError(t, err, "Failed to create light client finality update")
+
+	require.Equal(t, true, IsBetterFinalityUpdate(update1, update0), "update1 should be better than update0")
+	// update1 should not be valid for broadcast - meaning it should not be broadcasted
+	require.Equal(t, false, IsFinalityUpdateValidForBroadcast(update1, lcStore.LastFinalityUpdate()), "update1 should not be valid for broadcast")
+
+	lcStore.SetLastFinalityUpdate(update1, true)
+	require.Equal(t, update1, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should match the set value")
+	require.Equal(t, false, p2p.BroadcastCalled.Load(), "Broadcast should not have been called after setting a new last finality update without supermajority")
+	p2p.BroadcastCalled.Store(false) // Reset for next test
+
+	// update 2 with same finality slot, increased attested slot, and supermajority - should save and broadcast
+	l2 := util.NewTestLightClient(t, version.Altair, util.WithIncreasedAttestedSlot(2), util.WithSupermajority(0))
+	update2, err := NewLightClientFinalityUpdateFromBeaconState(l2.Ctx, l2.State, l2.Block, l2.AttestedState, l2.AttestedBlock, l2.FinalizedBlock)
+	require.NoError(t, err, "Failed to create light client finality update")
+
+	require.Equal(t, true, IsBetterFinalityUpdate(update2, update1), "update2 should be better than update1")
+	// update2 should be valid for broadcast - meaning it should be broadcasted
+	require.Equal(t, true, IsFinalityUpdateValidForBroadcast(update2, lcStore.LastFinalityUpdate()), "update2 should be valid for broadcast")
+
+	lcStore.SetLastFinalityUpdate(update2, true)
+	require.Equal(t, update2, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should match the set value")
+	require.Equal(t, true, p2p.BroadcastCalled.Load(), "Broadcast should have been called after setting a new last finality update with supermajority")
+	p2p.BroadcastCalled.Store(false) // Reset for next test
+
+	// update 3 with same finality slot, increased attested slot, and supermajority - should save but not broadcast
+	l3 := util.NewTestLightClient(t, version.Altair, util.WithIncreasedAttestedSlot(3), util.WithSupermajority(0))
+	update3, err := NewLightClientFinalityUpdateFromBeaconState(l3.Ctx, l3.State, l3.Block, l3.AttestedState, l3.AttestedBlock, l3.FinalizedBlock)
+	require.NoError(t, err, "Failed to create light client finality update")
+
+	require.Equal(t, true, IsBetterFinalityUpdate(update3, update2), "update3 should be better than update2")
+	// update3 should not be valid for broadcast - meaning it should not be broadcasted
+	require.Equal(t, false, IsFinalityUpdateValidForBroadcast(update3, lcStore.LastFinalityUpdate()), "update3 should not be valid for broadcast")
+
+	lcStore.SetLastFinalityUpdate(update3, true)
+	require.Equal(t, update3, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should match the set value")
+	require.Equal(t, false, p2p.BroadcastCalled.Load(), "Broadcast should not have been when previous was already broadcast")
+
+	// update 4 with increased finality slot, increased attested slot, and supermajority - should save and broadcast
+	l4 := util.NewTestLightClient(t, version.Altair, util.WithIncreasedFinalizedSlot(1), util.WithIncreasedAttestedSlot(1), util.WithSupermajority(0))
+	update4, err := NewLightClientFinalityUpdateFromBeaconState(l4.Ctx, l4.State, l4.Block, l4.AttestedState, l4.AttestedBlock, l4.FinalizedBlock)
+	require.NoError(t, err, "Failed to create light client finality update")
+
+	require.Equal(t, true, IsBetterFinalityUpdate(update4, update3), "update4 should be better than update3")
+	// update4 should be valid for broadcast - meaning it should be broadcasted
+	require.Equal(t, true, IsFinalityUpdateValidForBroadcast(update4, lcStore.LastFinalityUpdate()), "update4 should be valid for broadcast")
+
+	lcStore.SetLastFinalityUpdate(update4, true)
+	require.Equal(t, update4, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should match the set value")
+	require.Equal(t, true, p2p.BroadcastCalled.Load(), "Broadcast should have been called after a new finality update with increased finality slot")
+	p2p.BroadcastCalled.Store(false) // Reset for next test
+
+	// update 5 with the same new finality slot, increased attested slot, and supermajority - should save but not broadcast
+	l5 := util.NewTestLightClient(t, version.Altair, util.WithIncreasedFinalizedSlot(1), util.WithIncreasedAttestedSlot(2), util.WithSupermajority(0))
+	update5, err := NewLightClientFinalityUpdateFromBeaconState(l5.Ctx, l5.State, l5.Block, l5.AttestedState, l5.AttestedBlock, l5.FinalizedBlock)
+	require.NoError(t, err, "Failed to create light client finality update")
+
+	require.Equal(t, true, IsBetterFinalityUpdate(update5, update4), "update5 should be better than update4")
+	// update5 should not be valid for broadcast - meaning it should not be broadcasted
+	require.Equal(t, false, IsFinalityUpdateValidForBroadcast(update5, lcStore.LastFinalityUpdate()), "update5 should not be valid for broadcast")
+
+	lcStore.SetLastFinalityUpdate(update5, true)
+	require.Equal(t, update5, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should match the set value")
+	require.Equal(t, false, p2p.BroadcastCalled.Load(), "Broadcast should not have been called when previous was already broadcast with supermajority")
+
+	// update 6 with the same new finality slot, increased attested slot, and no supermajority - should save but not broadcast
+	l6 := util.NewTestLightClient(t, version.Altair, util.WithIncreasedFinalizedSlot(1), util.WithIncreasedAttestedSlot(3))
+	update6, err := NewLightClientFinalityUpdateFromBeaconState(l6.Ctx, l6.State, l6.Block, l6.AttestedState, l6.AttestedBlock, l6.FinalizedBlock)
+	require.NoError(t, err, "Failed to create light client finality update")
+
+	require.Equal(t, true, IsBetterFinalityUpdate(update6, update5), "update6 should be better than update5")
+	// update6 should not be valid for broadcast - meaning it should not be broadcasted
+	require.Equal(t, false, IsFinalityUpdateValidForBroadcast(update6, lcStore.LastFinalityUpdate()), "update6 should not be valid for broadcast")
+
+	lcStore.SetLastFinalityUpdate(update6, true)
+	require.Equal(t, update6, lcStore.LastFinalityUpdate(), "lastFinalityUpdate should match the set value")
+	require.Equal(t, false, p2p.BroadcastCalled.Load(), "Broadcast should not have been called when previous was already broadcast with supermajority")
+}
+
+func TestLightClientStore_SaveLCData(t *testing.T) {
+	t.Run("no parent in cache or db - new is head", func(t *testing.T) {
+		db := testDB.SetupDB(t)
+		s := NewLightClientStore(&p2pTesting.FakeP2P{}, new(event.Feed), db)
+		require.NotNil(t, s)
+
+		l := util.NewTestLightClient(t, version.Altair)
+
+		blkRoot, err := l.Block.Block().HashTreeRoot()
+		require.NoError(t, err)
+
+		require.NoError(t, s.SaveLCData(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock, blkRoot), "Failed to save light client data")
+
+		update, err := NewLightClientUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
+		require.NoError(t, err)
+		finalityUpdate, err := NewLightClientFinalityUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
+		require.NoError(t, err)
+		optimisticUpdate, err := NewLightClientOptimisticUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock)
+		require.NoError(t, err)
+		attstedBlkRoot, err := l.AttestedBlock.Block().HashTreeRoot()
+		require.NoError(t, err)
+
+		require.DeepEqual(t, finalityUpdate, s.lastFinalityUpdate, "Expected to find the last finality update in the store")
+		require.DeepEqual(t, optimisticUpdate, s.lastOptimisticUpdate, "Expected to find the last optimistic update in the store")
+		require.DeepEqual(t, update, s.cache.items[attstedBlkRoot].bestUpdate, "Expected to find the update in the non-finality cache")
+		require.DeepEqual(t, finalityUpdate, s.cache.items[attstedBlkRoot].bestFinalityUpdate, "Expected to find the finality update in the non-finality cache")
+	})
+
+	t.Run("no parent in cache or db - new not head", func(t *testing.T) {
+		db := testDB.SetupDB(t)
+		s := NewLightClientStore(&p2pTesting.FakeP2P{}, new(event.Feed), db)
+		require.NotNil(t, s)
+
+		l := util.NewTestLightClient(t, version.Altair)
+
+		blkRoot, err := l.FinalizedBlock.Block().HashTreeRoot()
+		require.NoError(t, err)
+
+		require.NoError(t, s.SaveLCData(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock, blkRoot), "Failed to save light client data")
+
+		update, err := NewLightClientUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
+		require.NoError(t, err)
+		finalityUpdate, err := NewLightClientFinalityUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
+		require.NoError(t, err)
+		optimisticUpdate, err := NewLightClientOptimisticUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock)
+		require.NoError(t, err)
+		attstedBlkRoot, err := l.AttestedBlock.Block().HashTreeRoot()
+		require.NoError(t, err)
+
+		require.IsNil(t, s.lastFinalityUpdate, "Expected to not find the last finality update in the store since the block is not head")
+		require.DeepEqual(t, optimisticUpdate, s.lastOptimisticUpdate, "Expected to find the last optimistic update in the store")
+		require.DeepEqual(t, update, s.cache.items[attstedBlkRoot].bestUpdate, "Expected to find the update in the non-finality cache")
+		require.DeepEqual(t, finalityUpdate, s.cache.items[attstedBlkRoot].bestFinalityUpdate, "Expected to find the finality update in the non-finality cache")
+	})
+
+	t.Run("parent in db", func(t *testing.T) {
+		db := testDB.SetupDB(t)
+		s := NewLightClientStore(&p2pTesting.FakeP2P{}, new(event.Feed), db)
+		require.NotNil(t, s)
+
+		l := util.NewTestLightClient(t, version.Altair)
+
+		// save an update for this period in db
+		period := slots.SyncCommitteePeriod(slots.ToEpoch(l.AttestedBlock.Block().Slot()))
+		update, err := NewLightClientUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
+		require.NoError(t, err)
+		require.NoError(t, db.SaveLightClientUpdate(l.Ctx, period, update), "Failed to save light client update in db")
+
+		l2 := util.NewTestLightClient(t, version.Altair, util.WithIncreasedAttestedSlot(1), util.WithSupermajority(0)) // updates from this setup should be all better
+
+		blkRoot, err := l2.Block.Block().HashTreeRoot()
+		require.NoError(t, err)
+
+		require.NoError(t, s.SaveLCData(l2.Ctx, l2.State, l2.Block, l2.AttestedState, l2.AttestedBlock, l2.FinalizedBlock, blkRoot), "Failed to save light client data")
+
+		update, err = NewLightClientUpdateFromBeaconState(l2.Ctx, l2.State, l2.Block, l2.AttestedState, l2.AttestedBlock, l2.FinalizedBlock)
+		require.NoError(t, err)
+		finalityUpdate, err := NewLightClientFinalityUpdateFromBeaconState(l2.Ctx, l2.State, l2.Block, l2.AttestedState, l2.AttestedBlock, l2.FinalizedBlock)
+		require.NoError(t, err)
+		optimisticUpdate, err := NewLightClientOptimisticUpdateFromBeaconState(l2.Ctx, l2.State, l2.Block, l2.AttestedState, l2.AttestedBlock)
+		require.NoError(t, err)
+		attstedBlkRoot, err := l2.AttestedBlock.Block().HashTreeRoot()
+		require.NoError(t, err)
+
+		require.DeepEqual(t, finalityUpdate, s.lastFinalityUpdate, "Expected to find the last finality update in the store")
+		require.DeepEqual(t, optimisticUpdate, s.lastOptimisticUpdate, "Expected to find the last optimistic update in the store")
+		require.DeepEqual(t, update, s.cache.items[attstedBlkRoot].bestUpdate, "Expected to find the update in the non-finality cache")
+		require.DeepEqual(t, finalityUpdate, s.cache.items[attstedBlkRoot].bestFinalityUpdate, "Expected to find the finality update in the non-finality cache")
+	})
+
+	t.Run("parent in cache", func(t *testing.T) {
+		db := testDB.SetupDB(t)
+		s := NewLightClientStore(&p2pTesting.FakeP2P{}, new(event.Feed), db)
+		require.NotNil(t, s)
+
+		l := util.NewTestLightClient(t, version.Altair)
+		l2 := util.NewTestLightClient(t, version.Altair, util.WithIncreasedAttestedSlot(1), util.WithSupermajority(0)) // updates from this setup should be all better
+
+		// save the cache item for this period in cache
+		period := slots.SyncCommitteePeriod(slots.ToEpoch(l.AttestedBlock.Block().Slot()))
+		update, err := NewLightClientUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
+		require.NoError(t, err)
+		finalityUpdate, err := NewLightClientFinalityUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
+		require.NoError(t, err)
+		item := &cacheItem{
+			period:             period,
+			bestUpdate:         update,
+			bestFinalityUpdate: finalityUpdate,
+		}
+		attestedBlockRoot := l2.AttestedBlock.Block().ParentRoot() // we want this item to be the parent of the new block
+		s.cache.items[attestedBlockRoot] = item
+
+		blkRoot, err := l2.Block.Block().HashTreeRoot()
+		require.NoError(t, err)
+
+		require.NoError(t, s.SaveLCData(l2.Ctx, l2.State, l2.Block, l2.AttestedState, l2.AttestedBlock, l2.FinalizedBlock, blkRoot), "Failed to save light client data")
+
+		update, err = NewLightClientUpdateFromBeaconState(l2.Ctx, l2.State, l2.Block, l2.AttestedState, l2.AttestedBlock, l2.FinalizedBlock)
+		require.NoError(t, err)
+		finalityUpdate, err = NewLightClientFinalityUpdateFromBeaconState(l2.Ctx, l2.State, l2.Block, l2.AttestedState, l2.AttestedBlock, l2.FinalizedBlock)
+		require.NoError(t, err)
+		optimisticUpdate, err := NewLightClientOptimisticUpdateFromBeaconState(l2.Ctx, l2.State, l2.Block, l2.AttestedState, l2.AttestedBlock)
+		require.NoError(t, err)
+		attstedBlkRoot, err := l2.AttestedBlock.Block().HashTreeRoot()
+		require.NoError(t, err)
+
+		require.DeepEqual(t, finalityUpdate, s.lastFinalityUpdate, "Expected to find the last finality update in the store")
+		require.DeepEqual(t, optimisticUpdate, s.lastOptimisticUpdate, "Expected to find the last optimistic update in the store")
+		require.DeepEqual(t, update, s.cache.items[attstedBlkRoot].bestUpdate, "Expected to find the update in the non-finality cache")
+		require.DeepEqual(t, finalityUpdate, s.cache.items[attstedBlkRoot].bestFinalityUpdate, "Expected to find the finality update in the non-finality cache")
+	})
+
+	t.Run("parent in the previous period", func(t *testing.T) {
+		db := testDB.SetupDB(t)
+		s := NewLightClientStore(&p2pTesting.FakeP2P{}, new(event.Feed), db)
+		require.NotNil(t, s)
+
+		l := util.NewTestLightClient(t, version.Altair)
+		l2 := util.NewTestLightClient(t, version.Bellatrix, util.WithIncreasedAttestedSlot(1), util.WithSupermajority(0)) // updates from this setup should be all better
+
+		// save the cache item for this period1 in cache
+		period1 := slots.SyncCommitteePeriod(slots.ToEpoch(l.AttestedBlock.Block().Slot()))
+		update, err := NewLightClientUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
+		require.NoError(t, err)
+		finalityUpdate, err := NewLightClientFinalityUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
+		require.NoError(t, err)
+		item := &cacheItem{
+			period:             period1,
+			bestUpdate:         update,
+			bestFinalityUpdate: finalityUpdate,
+		}
+		attestedBlockRoot := l2.AttestedBlock.Block().ParentRoot() // we want this item to be the parent of the new block
+		s.cache.items[attestedBlockRoot] = item
+
+		blkRoot, err := l2.Block.Block().HashTreeRoot()
+		require.NoError(t, err)
+
+		require.NoError(t, s.SaveLCData(l2.Ctx, l2.State, l2.Block, l2.AttestedState, l2.AttestedBlock, l2.FinalizedBlock, blkRoot), "Failed to save light client data")
+
+		update, err = NewLightClientUpdateFromBeaconState(l2.Ctx, l2.State, l2.Block, l2.AttestedState, l2.AttestedBlock, l2.FinalizedBlock)
+		require.NoError(t, err)
+		finalityUpdate, err = NewLightClientFinalityUpdateFromBeaconState(l2.Ctx, l2.State, l2.Block, l2.AttestedState, l2.AttestedBlock, l2.FinalizedBlock)
+		require.NoError(t, err)
+		optimisticUpdate, err := NewLightClientOptimisticUpdateFromBeaconState(l2.Ctx, l2.State, l2.Block, l2.AttestedState, l2.AttestedBlock)
+		require.NoError(t, err)
+		attstedBlkRoot, err := l2.AttestedBlock.Block().HashTreeRoot()
+		require.NoError(t, err)
+
+		require.DeepEqual(t, finalityUpdate, s.lastFinalityUpdate, "Expected to find the last finality update in the store")
+		require.DeepEqual(t, optimisticUpdate, s.lastOptimisticUpdate, "Expected to find the last optimistic update in the store")
+		require.DeepEqual(t, update, s.cache.items[attstedBlkRoot].bestUpdate, "Expected to find the update in the non-finality cache")
+		require.DeepEqual(t, finalityUpdate, s.cache.items[attstedBlkRoot].bestFinalityUpdate, "Expected to find the finality update in the non-finality cache")
+	})
+}
+
+func TestLightClientStore_MigrateToCold(t *testing.T) {
+	// This tests the scenario where chain advances but the cache is empty.
+	// It should see that there is nothing in the cache to migrate and just update the tail to the new finalized root.
+	t.Run("empty cache", func(t *testing.T) {
+		beaconDB := testDB.SetupDB(t)
+		ctx := context.Background()
+
+		finalizedBlockRoot, _ := saveInitialFinalizedCheckpointData(t, ctx, beaconDB)
+
+		s := NewLightClientStore(&p2pTesting.FakeP2P{}, new(event.Feed), beaconDB)
+		require.NotNil(t, s)
+
+		for i := 0; i < 3; i++ {
+			newBlock := util.NewBeaconBlock()
+			newBlock.Block.Slot = primitives.Slot(32 + uint64(i))
+			newBlock.Block.ParentRoot = finalizedBlockRoot[:]
+			signedNewBlock, err := blocks.NewSignedBeaconBlock(newBlock)
+			require.NoError(t, err)
+			blockRoot, err := signedNewBlock.Block().HashTreeRoot()
+			require.NoError(t, err)
+			require.NoError(t, beaconDB.SaveBlock(ctx, signedNewBlock))
+			finalizedBlockRoot = blockRoot
+		}
+
+		err := s.MigrateToCold(ctx, finalizedBlockRoot)
+		require.NoError(t, err)
+		require.Equal(t, 0, len(s.cache.items))
+	})
+
+	// This tests the scenario where chain advances but the CANONICAL cache is empty.
+	// It should see that there is nothing in the canonical cache to migrate and just update the tail to the new finalized root AND delete anything non-canonical.
+	t.Run("non canonical cache", func(t *testing.T) {
+		beaconDB := testDB.SetupDB(t)
+		ctx := context.Background()
+
+		finalizedBlockRoot, _ := saveInitialFinalizedCheckpointData(t, ctx, beaconDB)
+
+		s := NewLightClientStore(&p2pTesting.FakeP2P{}, new(event.Feed), beaconDB)
+		require.NotNil(t, s)
+
+		for i := 0; i < 3; i++ {
+			newBlock := util.NewBeaconBlock()
+			newBlock.Block.Slot = primitives.Slot(32 + uint64(i))
+			newBlock.Block.ParentRoot = finalizedBlockRoot[:]
+			signedNewBlock, err := blocks.NewSignedBeaconBlock(newBlock)
+			require.NoError(t, err)
+			blockRoot, err := signedNewBlock.Block().HashTreeRoot()
+			require.NoError(t, err)
+			require.NoError(t, beaconDB.SaveBlock(ctx, signedNewBlock))
+			finalizedBlockRoot = blockRoot
+		}
+
+		// Add a non-canonical item to the cache
+		cacheItem := &cacheItem{
+			period: 0,
+			slot:   33,
+		}
+		nonCanonicalBlockRoot := [32]byte{1, 2, 3, 4}
+		s.cache.items[nonCanonicalBlockRoot] = cacheItem
+
+		require.Equal(t, 1, len(s.cache.items))
+
+		err := s.MigrateToCold(ctx, finalizedBlockRoot)
+		require.NoError(t, err)
+		require.Equal(t, 0, len(s.cache.items), "Expected the non-canonical item in the cache to be deleted")
+	})
+
+	// db has update - cache has both canonical and non-canonical items.
+	// should update the update in db and delete cache.
+	t.Run("mixed cache - finality immediately after cache", func(t *testing.T) {
+		beaconDB := testDB.SetupDB(t)
+		ctx := context.Background()
+
+		finalizedBlockRoot, _ := saveInitialFinalizedCheckpointData(t, ctx, beaconDB)
+		require.NoError(t, beaconDB.SaveHeadBlockRoot(ctx, finalizedBlockRoot))
+
+		s := NewLightClientStore(&p2pTesting.FakeP2P{}, new(event.Feed), beaconDB)
+		require.NotNil(t, s)
+
+		// Save an update for this period in db
+		l := util.NewTestLightClient(t, version.Altair)
+		update, err := NewLightClientUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
+		require.NoError(t, err)
+		period := slots.SyncCommitteePeriod(slots.ToEpoch(l.AttestedBlock.Block().Slot()))
+		require.NoError(t, beaconDB.SaveLightClientUpdate(ctx, period, update))
+
+		lastBlockRoot := finalizedBlockRoot
+		lastAttestedRoot := finalizedBlockRoot
+		lastUpdate := update
+		for i := 1; i < 4; i++ {
+			l = util.NewTestLightClient(t, version.Altair, util.WithIncreasedAttestedSlot(uint64(i)), util.WithSupermajority(uint64(i)), util.WithAttestedParentRoot(lastAttestedRoot))
+			require.NoError(t, beaconDB.SaveBlock(ctx, l.Block))
+			require.NoError(t, s.SaveLCData(ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock, [32]byte{1}))
+			lastBlockRoot, err = l.Block.Block().HashTreeRoot()
+			require.NoError(t, err)
+			lastAttestedRoot, err = l.AttestedBlock.Block().HashTreeRoot()
+			require.NoError(t, err)
+			update, err = NewLightClientUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
+			require.NoError(t, err)
+			lastUpdate = update
+		}
+
+		require.Equal(t, 3, len(s.cache.items))
+
+		// Add a non-canonical item to the cache
+		cacheItem := &cacheItem{
+			period: 0,
+			slot:   33,
+		}
+		nonCanonicalBlockRoot := [32]byte{1, 2, 3, 4}
+		s.cache.items[nonCanonicalBlockRoot] = cacheItem
+
+		require.Equal(t, 4, len(s.cache.items))
+
+		err = s.MigrateToCold(ctx, lastBlockRoot)
+		require.NoError(t, err)
+		require.Equal(t, 0, len(s.cache.items), "Expected the non-canonical item in the cache to be deleted")
+		u, err := beaconDB.LightClientUpdate(ctx, period)
+		require.NoError(t, err)
+		require.NotNil(t, u)
+		require.DeepEqual(t, lastUpdate, u)
+	})
+
+	// db has update - cache has both canonical and non-canonical items. finalized height is in the middle.
+	// should update the update in db and delete items in cache before finalized slot.
+	t.Run("mixed cache - finality middle of cache", func(t *testing.T) {
+		beaconDB := testDB.SetupDB(t)
+		ctx := context.Background()
+
+		finalizedBlockRoot, _ := saveInitialFinalizedCheckpointData(t, ctx, beaconDB)
+		require.NoError(t, beaconDB.SaveHeadBlockRoot(ctx, finalizedBlockRoot))
+
+		s := NewLightClientStore(&p2pTesting.FakeP2P{}, new(event.Feed), beaconDB)
+		require.NotNil(t, s)
+
+		// Save an update for this period in db
+		l := util.NewTestLightClient(t, version.Altair)
+		update, err := NewLightClientUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
+		require.NoError(t, err)
+		period := slots.SyncCommitteePeriod(slots.ToEpoch(l.AttestedBlock.Block().Slot()))
+		require.NoError(t, beaconDB.SaveLightClientUpdate(ctx, period, update))
+
+		lastBlockRoot := finalizedBlockRoot
+		lastUpdate := update
+		lastAttestedRoot := [32]byte{}
+		for i := 1; i < 4; i++ {
+			l = util.NewTestLightClient(t, version.Altair, util.WithIncreasedAttestedSlot(uint64(i)), util.WithSupermajority(uint64(i)), util.WithAttestedParentRoot(lastAttestedRoot))
+			require.NoError(t, beaconDB.SaveBlock(ctx, l.Block))
+			require.NoError(t, s.SaveLCData(ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock, [32]byte{1}))
+			root, err := l.Block.Block().HashTreeRoot()
+			require.NoError(t, err)
+			lastBlockRoot = root
+			update, err = NewLightClientUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
+			require.NoError(t, err)
+			lastUpdate = update
+			lastAttestedRoot, err = l.AttestedBlock.Block().HashTreeRoot()
+			require.NoError(t, err)
+		}
+
+		require.Equal(t, 3, len(s.cache.items))
+
+		// Add a non-canonical item to the cache
+		cacheItem := &cacheItem{
+			period: 0,
+			slot:   33,
+		}
+		nonCanonicalBlockRoot := [32]byte{1, 2, 3, 4}
+		s.cache.items[nonCanonicalBlockRoot] = cacheItem
+
+		require.Equal(t, 4, len(s.cache.items))
+
+		for i := 4; i < 7; i++ {
+			l = util.NewTestLightClient(t, version.Altair, util.WithIncreasedAttestedSlot(uint64(i)), util.WithSupermajority(0), util.WithAttestedParentRoot(lastAttestedRoot))
+			require.NoError(t, beaconDB.SaveBlock(ctx, l.Block))
+			require.NoError(t, s.SaveLCData(ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock, [32]byte{1}))
+			lastAttestedRoot, err = l.AttestedBlock.Block().HashTreeRoot()
+			require.NoError(t, err)
+		}
+
+		require.Equal(t, 7, len(s.cache.items))
+
+		err = s.MigrateToCold(ctx, lastBlockRoot)
+		require.NoError(t, err)
+		require.Equal(t, 3, len(s.cache.items), "Expected the non-canonical item in the cache to be deleted")
+		u, err := beaconDB.LightClientUpdate(ctx, period)
+		require.NoError(t, err)
+		require.NotNil(t, u)
+		require.DeepEqual(t, lastUpdate, u)
+	})
+
+	// we have multiple periods in the cache before finalization happens. we expect all of them to be saved in db.
+	t.Run("finality after multiple periods in cache", func(t *testing.T) {
+		beaconDB := testDB.SetupDB(t)
+		ctx := context.Background()
+
+		cfg := params.BeaconConfig().Copy()
+		cfg.EpochsPerSyncCommitteePeriod = 1
+		params.OverrideBeaconConfig(cfg)
+
+		finalizedBlockRoot, _ := saveInitialFinalizedCheckpointData(t, ctx, beaconDB)
+		require.NoError(t, beaconDB.SaveHeadBlockRoot(ctx, finalizedBlockRoot))
+
+		s := NewLightClientStore(&p2pTesting.FakeP2P{}, new(event.Feed), beaconDB)
+		require.NotNil(t, s)
+
+		// Save an update for this period1 in db
+		l := util.NewTestLightClient(t, version.Altair)
+		update, err := NewLightClientUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
+		require.NoError(t, err)
+		period1 := slots.SyncCommitteePeriod(slots.ToEpoch(l.AttestedBlock.Block().Slot()))
+		require.NoError(t, beaconDB.SaveLightClientUpdate(ctx, period1, update))
+
+		lastBlockRoot := finalizedBlockRoot
+		lastUpdatePeriod1 := update
+		lastAttestedRoot := [32]byte{}
+		for i := 1; i < 4; i++ {
+			l = util.NewTestLightClient(t, version.Altair, util.WithIncreasedAttestedSlot(uint64(i)), util.WithSupermajority(uint64(i)), util.WithAttestedParentRoot(lastAttestedRoot))
+			require.NoError(t, beaconDB.SaveBlock(ctx, l.Block))
+			require.NoError(t, s.SaveLCData(ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock, [32]byte{1}))
+			root, err := l.Block.Block().HashTreeRoot()
+			require.NoError(t, err)
+			lastBlockRoot = root
+			lastUpdatePeriod1, err = NewLightClientUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
+			require.NoError(t, err)
+			lastAttestedRoot, err = l.AttestedBlock.Block().HashTreeRoot()
+			require.NoError(t, err)
+		}
+
+		period2 := period1
+		var lastUpdatePeriod2 interfaces.LightClientUpdate
+		for i := 1; i < 4; i++ {
+			l = util.NewTestLightClient(t, version.Altair, util.WithIncreasedAttestedSlot(uint64(i)+33), util.WithSupermajority(uint64(i)), util.WithAttestedParentRoot(lastAttestedRoot))
+			require.NoError(t, beaconDB.SaveBlock(ctx, l.Block))
+			require.NoError(t, s.SaveLCData(ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock, [32]byte{1}))
+			root, err := l.Block.Block().HashTreeRoot()
+			require.NoError(t, err)
+			lastBlockRoot = root
+			lastUpdatePeriod2, err = NewLightClientUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
+			require.NoError(t, err)
+			lastAttestedRoot, err = l.AttestedBlock.Block().HashTreeRoot()
+			require.NoError(t, err)
+			period2 = slots.SyncCommitteePeriod(slots.ToEpoch(l.AttestedBlock.Block().Slot()))
+		}
+
+		require.Equal(t, 6, len(s.cache.items))
+
+		// Add a non-canonical item to the cache
+		cacheItem := &cacheItem{
+			period: 0,
+			slot:   33,
+		}
+		nonCanonicalBlockRoot := [32]byte{1, 2, 3, 4}
+		s.cache.items[nonCanonicalBlockRoot] = cacheItem
+
+		require.Equal(t, 7, len(s.cache.items))
+
+		for i := 4; i < 7; i++ {
+			l = util.NewTestLightClient(t, version.Altair, util.WithIncreasedAttestedSlot(uint64(i)+33), util.WithSupermajority(0), util.WithAttestedParentRoot(lastAttestedRoot))
+			require.NoError(t, beaconDB.SaveBlock(ctx, l.Block))
+			require.NoError(t, s.SaveLCData(ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock, [32]byte{1}))
+			lastAttestedRoot, err = l.AttestedBlock.Block().HashTreeRoot()
+			require.NoError(t, err)
+		}
+
+		require.Equal(t, 10, len(s.cache.items))
+
+		err = s.MigrateToCold(ctx, lastBlockRoot)
+		require.NoError(t, err)
+		require.Equal(t, 3, len(s.cache.items), "Expected the non-canonical item in the cache to be deleted")
+		u, err := beaconDB.LightClientUpdate(ctx, period2)
+		require.NoError(t, err)
+		require.NotNil(t, u)
+		require.DeepEqual(t, lastUpdatePeriod2, u)
+		u, err = beaconDB.LightClientUpdate(ctx, period1)
+		require.NoError(t, err)
+		require.NotNil(t, u)
+		require.DeepEqual(t, lastUpdatePeriod1, u)
+	})
+}
+
+func saveInitialFinalizedCheckpointData(t *testing.T, ctx context.Context, beaconDB db.Database) ([32]byte, interfaces.SignedBeaconBlock) {
+	genesis := util.NewBeaconBlock()
+	genesisRoot, err := genesis.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, genesisRoot))
+	util.SaveBlock(t, ctx, beaconDB, genesis)
+	genesisState, err := util.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveState(ctx, genesisState, genesisRoot))
+
+	finalizedState, err := util.NewBeaconState()
+	require.NoError(t, err)
+	finalizedBlock := util.NewBeaconBlock()
+	finalizedBlock.Block.Slot = 32
+	finalizedBlock.Block.ParentRoot = genesisRoot[:]
+	signedFinalizedBlock, err := blocks.NewSignedBeaconBlock(finalizedBlock)
+	require.NoError(t, err)
+	finalizedBlockHeader, err := signedFinalizedBlock.Header()
+	require.NoError(t, err)
+	require.NoError(t, finalizedState.SetLatestBlockHeader(finalizedBlockHeader.Header))
+	finalizedStateRoot, err := finalizedState.HashTreeRoot(ctx)
+	require.NoError(t, err)
+	finalizedBlock.Block.StateRoot = finalizedStateRoot[:]
+	signedFinalizedBlock, err = blocks.NewSignedBeaconBlock(finalizedBlock)
+	require.NoError(t, err)
+	finalizedBlockRoot, err := signedFinalizedBlock.Block().HashTreeRoot()
+	require.NoError(t, err)
+	cp := ethpb.Checkpoint{
+		Epoch: 1,
+		Root:  finalizedBlockRoot[:],
+	}
+	require.NoError(t, beaconDB.SaveBlock(ctx, signedFinalizedBlock))
+	require.NoError(t, beaconDB.SaveState(ctx, finalizedState, finalizedBlockRoot))
+	require.NoError(t, beaconDB.SaveFinalizedCheckpoint(ctx, &cp))
+
+	return finalizedBlockRoot, signedFinalizedBlock
+}
+
+func TestLightClientStore_LightClientUpdatesByRange(t *testing.T) {
+	t.Run("no updates", func(t *testing.T) {
+		d := testDB.SetupDB(t)
+		ctx := context.Background()
+
+		_, finalizedBlock := saveInitialFinalizedCheckpointData(t, ctx, d)
+
+		s := NewLightClientStore(&p2pTesting.FakeP2P{}, new(event.Feed), d)
+		require.NotNil(t, s)
+
+		updates, err := s.LightClientUpdates(ctx, 2, 5, finalizedBlock)
+		require.NoError(t, err)
+		require.Equal(t, 0, len(updates))
+	})
+
+	t.Run("single update from db", func(t *testing.T) {
+		d := testDB.SetupDB(t)
+		ctx := context.Background()
+
+		_, finalizedBlock := saveInitialFinalizedCheckpointData(t, ctx, d)
+
+		s := NewLightClientStore(&p2pTesting.FakeP2P{}, new(event.Feed), d)
+		require.NotNil(t, s)
+
+		l := util.NewTestLightClient(t, version.Altair)
+		update, err := NewLightClientUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
+		require.NoError(t, err)
+
+		require.NoError(t, d.SaveLightClientUpdate(ctx, 3, update))
+
+		updates, err := s.LightClientUpdates(ctx, 3, 3, finalizedBlock)
+		require.NoError(t, err)
+		require.Equal(t, 1, len(updates))
+		require.DeepEqual(t, update, updates[0], "Expected to find the update in the store")
+	})
+
+	t.Run("multiple updates from db", func(t *testing.T) {
+		d := testDB.SetupDB(t)
+		ctx := context.Background()
+
+		_, finalizedBlock := saveInitialFinalizedCheckpointData(t, ctx, d)
+
+		s := NewLightClientStore(&p2pTesting.FakeP2P{}, new(event.Feed), d)
+		require.NotNil(t, s)
+
+		l := util.NewTestLightClient(t, version.Altair)
+		update, err := NewLightClientUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
+		require.NoError(t, err)
+
+		require.NoError(t, d.SaveLightClientUpdate(ctx, 3, update))
+		require.NoError(t, d.SaveLightClientUpdate(ctx, 4, update))
+		require.NoError(t, d.SaveLightClientUpdate(ctx, 5, update))
+
+		updates, err := s.LightClientUpdates(ctx, 3, 5, finalizedBlock)
+		require.NoError(t, err)
+		require.Equal(t, 3, len(updates))
+		require.DeepEqual(t, update, updates[0], "Expected to find the update in the store")
+		require.DeepEqual(t, update, updates[1], "Expected to find the update in the store")
+		require.DeepEqual(t, update, updates[2], "Expected to find the update in the store")
+	})
+
+	t.Run("single update from cache", func(t *testing.T) {
+		d := testDB.SetupDB(t)
+		ctx := context.Background()
+
+		_, _ = saveInitialFinalizedCheckpointData(t, ctx, d)
+
+		s := NewLightClientStore(&p2pTesting.FakeP2P{}, new(event.Feed), d)
+		require.NotNil(t, s)
+
+		l := util.NewTestLightClient(t, version.Altair)
+		update, err := NewLightClientUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
+		require.NoError(t, err)
+
+		cacheItem := &cacheItem{
+			period:     3,
+			bestUpdate: update,
+		}
+		s.cache.items[[32]byte{3}] = cacheItem
+
+		_, headBlock := saveStateAndBlockWithParentRoot(t, ctx, d, [32]byte{3})
+
+		updates, err := s.LightClientUpdates(ctx, 3, 3, headBlock)
+		require.NoError(t, err)
+		require.Equal(t, 1, len(updates))
+		require.DeepEqual(t, update, updates[0], "Expected to find the update in the store")
+	})
+
+	t.Run("multiple updates from cache", func(t *testing.T) {
+		d := testDB.SetupDB(t)
+		ctx := context.Background()
+
+		_, _ = saveInitialFinalizedCheckpointData(t, ctx, d)
+
+		s := NewLightClientStore(&p2pTesting.FakeP2P{}, new(event.Feed), d)
+		require.NotNil(t, s)
+
+		l := util.NewTestLightClient(t, version.Altair)
+		update, err := NewLightClientUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
+		require.NoError(t, err)
+
+		cacheItemP3 := &cacheItem{
+			period:     3,
+			bestUpdate: update,
+		}
+		s.cache.items[[32]byte{3}] = cacheItemP3
+
+		cacheItemP4 := &cacheItem{
+			period:     4,
+			bestUpdate: update,
+			parent:     cacheItemP3,
+		}
+		s.cache.items[[32]byte{4}] = cacheItemP4
+
+		cacheItemP5 := &cacheItem{
+			period:     5,
+			bestUpdate: update,
+			parent:     cacheItemP4,
+		}
+		s.cache.items[[32]byte{5}] = cacheItemP5
+
+		_, headBlock := saveStateAndBlockWithParentRoot(t, ctx, d, [32]byte{5})
+
+		updates, err := s.LightClientUpdates(ctx, 3, 5, headBlock)
+		require.NoError(t, err)
+		require.Equal(t, 3, len(updates))
+		require.DeepEqual(t, update, updates[0], "Expected to find the update in the store")
+		require.DeepEqual(t, update, updates[1], "Expected to find the update in the store")
+		require.DeepEqual(t, update, updates[2], "Expected to find the update in the store")
+	})
+
+	t.Run("multiple updates from both db and cache - no overlap", func(t *testing.T) {
+		d := testDB.SetupDB(t)
+		ctx := context.Background()
+
+		_, _ = saveInitialFinalizedCheckpointData(t, ctx, d)
+
+		s := NewLightClientStore(&p2pTesting.FakeP2P{}, new(event.Feed), d)
+		require.NotNil(t, s)
+
+		l := util.NewTestLightClient(t, version.Altair)
+		update, err := NewLightClientUpdateFromBeaconState(l.Ctx, l.State, l.Block, l.AttestedState, l.AttestedBlock, l.FinalizedBlock)
+		require.NoError(t, err)
+
+		require.NoError(t, d.SaveLightClientUpdate(ctx, 1, update))
+		require.NoError(t, d.SaveLightClientUpdate(ctx, 2, update))
+
+		cacheItemP3 := &cacheItem{
+			period:     3,
+			bestUpdate: update,
+		}
+		s.cache.items[[32]byte{3}] = cacheItemP3
+
+		cacheItemP4 := &cacheItem{
+			period:     4,
+			bestUpdate: update,
+			parent:     cacheItemP3,
+		}
+		s.cache.items[[32]byte{4}] = cacheItemP4
+
+		cacheItemP5 := &cacheItem{
+			period:     5,
+			bestUpdate: update,
+			parent:     cacheItemP4,
+		}
+		s.cache.items[[32]byte{5}] = cacheItemP5
+
+		_, headBlock := saveStateAndBlockWithParentRoot(t, ctx, d, [32]byte{5})
+
+		updates, err := s.LightClientUpdates(ctx, 1, 5, headBlock)
+		require.NoError(t, err)
+		require.Equal(t, 5, len(updates))
+		for i := 0; i < 5; i++ {
+			require.DeepEqual(t, update, updates[i], "Expected to find the update in the store")
+		}
+	})
+
+	t.Run("multiple updates from both db and cache - overlap", func(t *testing.T) {
+		d := testDB.SetupDB(t)
+		ctx := context.Background()
+
+		_, _ = saveInitialFinalizedCheckpointData(t, ctx, d)
+
+		s := NewLightClientStore(&p2pTesting.FakeP2P{}, new(event.Feed), d)
+		require.NotNil(t, s)
+
+		l1 := util.NewTestLightClient(t, version.Altair)
+		update1, err := NewLightClientUpdateFromBeaconState(l1.Ctx, l1.State, l1.Block, l1.AttestedState, l1.AttestedBlock, l1.FinalizedBlock)
+		require.NoError(t, err)
+
+		l2 := util.NewTestLightClient(t, version.Altair, util.WithIncreasedAttestedSlot(1))
+		update2, err := NewLightClientUpdateFromBeaconState(l2.Ctx, l2.State, l2.Block, l2.AttestedState, l2.AttestedBlock, l2.FinalizedBlock)
+		require.NoError(t, err)
+
+		require.DeepNotEqual(t, update1, update2)
+
+		require.NoError(t, d.SaveLightClientUpdate(ctx, 1, update1))
+		require.NoError(t, d.SaveLightClientUpdate(ctx, 2, update1))
+		require.NoError(t, d.SaveLightClientUpdate(ctx, 3, update1))
+		require.NoError(t, d.SaveLightClientUpdate(ctx, 4, update1))
+
+		cacheItemP3 := &cacheItem{
+			period:     3,
+			bestUpdate: update2,
+		}
+		s.cache.items[[32]byte{3}] = cacheItemP3
+
+		cacheItemP4 := &cacheItem{
+			period:     4,
+			bestUpdate: update2,
+			parent:     cacheItemP3,
+		}
+		s.cache.items[[32]byte{4}] = cacheItemP4
+
+		cacheItemP5 := &cacheItem{
+			period:     5,
+			bestUpdate: update2,
+			parent:     cacheItemP4,
+		}
+		s.cache.items[[32]byte{5}] = cacheItemP5
+
+		_, headBlock := saveStateAndBlockWithParentRoot(t, ctx, d, [32]byte{5})
+
+		updates, err := s.LightClientUpdates(ctx, 1, 5, headBlock)
+		require.NoError(t, err)
+		require.Equal(t, 5, len(updates))
+		// first two updates should be update1
+		for i := 0; i < 2; i++ {
+			require.DeepEqual(t, update1, updates[i], "Expected to find the update in the store")
+		}
+		// next three updates should be update2 - as cache overrides db
+		for i := 2; i < 5; i++ {
+			require.DeepEqual(t, update2, updates[i], "Expected to find the update in the store")
+		}
+	})
+
+	t.Run("first continuous range", func(t *testing.T) {
+		d := testDB.SetupDB(t)
+		ctx := context.Background()
+
+		_, _ = saveInitialFinalizedCheckpointData(t, ctx, d)
+
+		s := NewLightClientStore(&p2pTesting.FakeP2P{}, new(event.Feed), d)
+		require.NotNil(t, s)
+
+		l1 := util.NewTestLightClient(t, version.Altair)
+		update, err := NewLightClientUpdateFromBeaconState(l1.Ctx, l1.State, l1.Block, l1.AttestedState, l1.AttestedBlock, l1.FinalizedBlock)
+		require.NoError(t, err)
+
+		require.NoError(t, d.SaveLightClientUpdate(ctx, 1, update))
+		require.NoError(t, d.SaveLightClientUpdate(ctx, 2, update))
+
+		cacheItemP4 := &cacheItem{
+			period:     4,
+			bestUpdate: update,
+		}
+		s.cache.items[[32]byte{4}] = cacheItemP4
+
+		cacheItemP5 := &cacheItem{
+			period:     5,
+			bestUpdate: update,
+			parent:     cacheItemP4,
+		}
+		s.cache.items[[32]byte{5}] = cacheItemP5
+
+		_, headBlock := saveStateAndBlockWithParentRoot(t, ctx, d, [32]byte{5})
+
+		updates, err := s.LightClientUpdates(ctx, 1, 5, headBlock)
+		require.NoError(t, err)
+		require.Equal(t, 2, len(updates))
+		require.DeepEqual(t, update, updates[0], "Expected to find the update in the store")
+		require.DeepEqual(t, update, updates[1], "Expected to find the update in the store")
+	})
+
+}
+
+func saveStateAndBlockWithParentRoot(t *testing.T, ctx context.Context, d db.Database, parentRoot [32]byte) ([32]byte, interfaces.SignedBeaconBlock) {
+	blk := util.NewBeaconBlock()
+	blk.Block.ParentRoot = parentRoot[:]
+
+	blkRoot, err := blk.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	util.SaveBlock(t, ctx, d, blk)
+
+	st, err := util.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, d.SaveState(ctx, st, blkRoot))
+
+	signedFinalizedBlock, err := blocks.NewSignedBeaconBlock(blk)
+	require.NoError(t, err)
+
+	return blkRoot, signedFinalizedBlock
+}

beacon-chain/node/BUILD.bazel

@@ -23,7 +23,6 @@ go_library(
         "//beacon-chain/builder:go_default_library",
         "//beacon-chain/cache:go_default_library",
         "//beacon-chain/cache/depositsnapshot:go_default_library",
-        "//beacon-chain/core/light-client:go_default_library",
         "//beacon-chain/db:go_default_library",
         "//beacon-chain/db/filesystem:go_default_library",
         "//beacon-chain/db/kv:go_default_library",
@@ -32,6 +31,7 @@ go_library(
         "//beacon-chain/execution:go_default_library",
         "//beacon-chain/forkchoice:go_default_library",
         "//beacon-chain/forkchoice/doubly-linked-tree:go_default_library",
+        "//beacon-chain/light-client:go_default_library",
         "//beacon-chain/monitor:go_default_library",
         "//beacon-chain/node/registration:go_default_library",
         "//beacon-chain/operations/attestations:go_default_library",

beacon-chain/node/node.go

@@ -25,7 +25,6 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/builder"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/cache"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/cache/depositsnapshot"
-	lightclient "github.com/OffchainLabs/prysm/v6/beacon-chain/core/light-client"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filesystem"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/kv"
@@ -34,6 +33,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/execution"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/forkchoice"
 	doublylinkedtree "github.com/OffchainLabs/prysm/v6/beacon-chain/forkchoice/doubly-linked-tree"
+	lightclient "github.com/OffchainLabs/prysm/v6/beacon-chain/light-client"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/monitor"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/node/registration"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/operations/attestations"
@@ -253,10 +253,6 @@ func New(cliCtx *cli.Context, cancel context.CancelFunc, opts ...Option) (*Beaco
 	// their initialization.
 	beacon.finalizedStateAtStartUp = nil
 
-	if features.Get().EnableLightClient {
-		beacon.lcStore = lightclient.NewLightClientStore(beacon.db, beacon.fetchP2P(), beacon.StateFeed())
-	}
-
 	return beacon, nil
 }
 
@@ -349,6 +345,11 @@ func registerServices(cliCtx *cli.Context, beacon *BeaconNode, synchronizer *sta
 		return errors.Wrap(err, "could not register P2P service")
 	}
 
+	if features.Get().EnableLightClient {
+		log.Debugln("Registering Light Client Store")
+		beacon.registerLightClientStore()
+	}
+
 	log.Debugln("Registering Backfill Service")
 	if err := beacon.RegisterBackfillService(cliCtx, bfs); err != nil {
 		return errors.Wrap(err, "could not register Back Fill service")
@@ -621,35 +622,55 @@ func (b *BeaconNode) startStateGen(ctx context.Context, bfs coverage.AvailableBl
 	return nil
 }
 
+func parseIPNetStrings(ipWhitelist []string) ([]*net.IPNet, error) {
+	ipNets := make([]*net.IPNet, 0, len(ipWhitelist))
+	for _, cidr := range ipWhitelist {
+		_, ipNet, err := net.ParseCIDR(cidr)
+		if err != nil {
+			log.WithError(err).WithField("cidr", cidr).Error("Invalid CIDR in IP colocation whitelist")
+			return nil, err
+		}
+		ipNets = append(ipNets, ipNet)
+		log.WithField("cidr", cidr).Info("Added IP to colocation whitelist")
+	}
+	return ipNets, nil
+}
+
 func (b *BeaconNode) registerP2P(cliCtx *cli.Context) error {
 	bootstrapNodeAddrs, dataDir, err := registration.P2PPreregistration(cliCtx)
 	if err != nil {
 		return errors.Wrapf(err, "could not register p2p service")
 	}
 
+	colocationWhitelist, err := parseIPNetStrings(slice.SplitCommaSeparated(cliCtx.StringSlice(cmd.P2PColocationWhitelist.Name)))
+	if err != nil {
+		return fmt.Errorf("failed to register p2p service: %w", err)
+	}
+
 	svc, err := p2p.NewService(b.ctx, &p2p.Config{
-		NoDiscovery:          cliCtx.Bool(cmd.NoDiscovery.Name),
-		StaticPeers:          slice.SplitCommaSeparated(cliCtx.StringSlice(cmd.StaticPeers.Name)),
-		Discv5BootStrapAddrs: p2p.ParseBootStrapAddrs(bootstrapNodeAddrs),
-		RelayNodeAddr:        cliCtx.String(cmd.RelayNode.Name),
-		DataDir:              dataDir,
-		DiscoveryDir:         filepath.Join(dataDir, "discovery"),
-		LocalIP:              cliCtx.String(cmd.P2PIP.Name),
-		HostAddress:          cliCtx.String(cmd.P2PHost.Name),
-		HostDNS:              cliCtx.String(cmd.P2PHostDNS.Name),
-		PrivateKey:           cliCtx.String(cmd.P2PPrivKey.Name),
-		StaticPeerID:         cliCtx.Bool(cmd.P2PStaticID.Name),
-		QUICPort:             cliCtx.Uint(cmd.P2PQUICPort.Name),
-		TCPPort:              cliCtx.Uint(cmd.P2PTCPPort.Name),
-		UDPPort:              cliCtx.Uint(cmd.P2PUDPPort.Name),
-		MaxPeers:             cliCtx.Uint(cmd.P2PMaxPeers.Name),
-		QueueSize:            cliCtx.Uint(cmd.PubsubQueueSize.Name),
-		AllowListCIDR:        cliCtx.String(cmd.P2PAllowList.Name),
-		DenyListCIDR:         slice.SplitCommaSeparated(cliCtx.StringSlice(cmd.P2PDenyList.Name)),
-		EnableUPnP:           cliCtx.Bool(cmd.EnableUPnPFlag.Name),
-		StateNotifier:        b,
-		DB:                   b.db,
-		ClockWaiter:          b.clockWaiter,
+		NoDiscovery:           cliCtx.Bool(cmd.NoDiscovery.Name),
+		StaticPeers:           slice.SplitCommaSeparated(cliCtx.StringSlice(cmd.StaticPeers.Name)),
+		Discv5BootStrapAddrs:  p2p.ParseBootStrapAddrs(bootstrapNodeAddrs),
+		RelayNodeAddr:         cliCtx.String(cmd.RelayNode.Name),
+		DataDir:               dataDir,
+		DiscoveryDir:          filepath.Join(dataDir, "discovery"),
+		LocalIP:               cliCtx.String(cmd.P2PIP.Name),
+		HostAddress:           cliCtx.String(cmd.P2PHost.Name),
+		HostDNS:               cliCtx.String(cmd.P2PHostDNS.Name),
+		PrivateKey:            cliCtx.String(cmd.P2PPrivKey.Name),
+		StaticPeerID:          cliCtx.Bool(cmd.P2PStaticID.Name),
+		QUICPort:              cliCtx.Uint(cmd.P2PQUICPort.Name),
+		TCPPort:               cliCtx.Uint(cmd.P2PTCPPort.Name),
+		UDPPort:               cliCtx.Uint(cmd.P2PUDPPort.Name),
+		MaxPeers:              cliCtx.Uint(cmd.P2PMaxPeers.Name),
+		QueueSize:             cliCtx.Uint(cmd.PubsubQueueSize.Name),
+		AllowListCIDR:         cliCtx.String(cmd.P2PAllowList.Name),
+		DenyListCIDR:          slice.SplitCommaSeparated(cliCtx.StringSlice(cmd.P2PDenyList.Name)),
+		IPColocationWhitelist: colocationWhitelist,
+		EnableUPnP:            cliCtx.Bool(cmd.EnableUPnPFlag.Name),
+		StateNotifier:         b,
+		DB:                    b.db,
+		ClockWaiter:           b.clockWaiter,
 	})
 	if err != nil {
 		return err
@@ -941,6 +962,7 @@ func (b *BeaconNode) registerRPCService(router *http.ServeMux) error {
 		FinalizationFetcher:       chainService,
 		BlockReceiver:             chainService,
 		BlobReceiver:              chainService,
+		DataColumnReceiver:        chainService,
 		AttestationReceiver:       chainService,
 		GenesisTimeFetcher:        chainService,
 		GenesisFetcher:            chainService,
@@ -1118,6 +1140,11 @@ func (b *BeaconNode) RegisterBackfillService(cliCtx *cli.Context, bfs *backfill.
 	return b.services.RegisterService(bf)
 }
 
+func (b *BeaconNode) registerLightClientStore() {
+	lcs := lightclient.NewLightClientStore(b.fetchP2P(), b.StateFeed(), b.db)
+	b.lcStore = lcs
+}
+
 func hasNetworkFlag(cliCtx *cli.Context) bool {
 	for _, flag := range features.NetworkFlags {
 		for _, name := range flag.Names() {

beacon-chain/node/node_test.go

@@ -74,7 +74,9 @@ func TestNodeStart_Ok(t *testing.T) {
 	set := flag.NewFlagSet("test", 0)
 	set.String("datadir", tmp, "node data directory")
 	set.String("suggested-fee-recipient", "0x6e35733c5af9B61374A128e6F85f553aF09ff89A", "fee recipient")
+	set.Bool("enable-light-client", true, "enable light client")
 	require.NoError(t, set.Set("suggested-fee-recipient", "0x6e35733c5af9B61374A128e6F85f553aF09ff89A"))
+	require.NoError(t, set.Set("enable-light-client", "true"))
 
 	ctx, cancel := newCliContextWithCancel(&app, set)
 
@@ -88,6 +90,7 @@ func TestNodeStart_Ok(t *testing.T) {
 
 	node, err := New(ctx, cancel, options...)
 	require.NoError(t, err)
+	require.NotNil(t, node.lcStore)
 	node.services = &runtime.ServiceRegistry{}
 	go func() {
 		node.Start()
@@ -262,3 +265,46 @@ func TestCORS(t *testing.T) {
 		})
 	}
 }
+
+func TestParseIPNetStrings(t *testing.T) {
+	tests := []struct {
+		name      string
+		whitelist []string
+		wantCount int
+		wantError string
+	}{
+		{
+			name:      "empty whitelist",
+			whitelist: []string{},
+			wantCount: 0,
+		},
+		{
+			name:      "single IP whitelist",
+			whitelist: []string{"192.168.1.1/32"},
+			wantCount: 1,
+		},
+		{
+			name:      "multiple IPs whitelist",
+			whitelist: []string{"192.168.1.0/24", "10.0.0.0/8", "34.42.19.170/32"},
+			wantCount: 3,
+		},
+		{
+			name:      "invalid CIDR returns error",
+			whitelist: []string{"192.168.1.0/24", "invalid-cidr", "10.0.0.0/8"},
+			wantCount: 0,
+			wantError: "invalid CIDR address",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result, err := parseIPNetStrings(tt.whitelist)
+			assert.Equal(t, tt.wantCount, len(result))
+			if len(tt.wantError) == 0 {
+				assert.Equal(t, nil, err)
+			} else {
+				assert.ErrorContains(t, tt.wantError, err)
+			}
+		})
+	}
+}

beacon-chain/p2p/BUILD.bazel

@@ -60,6 +60,7 @@ go_library(
         "//config/features:go_default_library",
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
+        "//consensus-types/blocks:go_default_library",
         "//consensus-types/interfaces:go_default_library",
         "//consensus-types/primitives:go_default_library",
         "//consensus-types/wrapper:go_default_library",
@@ -95,6 +96,7 @@ go_library(
         "@com_github_libp2p_go_libp2p//core/peer:go_default_library",
         "@com_github_libp2p_go_libp2p//core/peerstore:go_default_library",
         "@com_github_libp2p_go_libp2p//core/protocol:go_default_library",
+        "@com_github_libp2p_go_libp2p//p2p/net/connmgr:go_default_library",
         "@com_github_libp2p_go_libp2p//p2p/security/noise:go_default_library",
         "@com_github_libp2p_go_libp2p//p2p/transport/quic:go_default_library",
         "@com_github_libp2p_go_libp2p//p2p/transport/tcp:go_default_library",
@@ -184,6 +186,7 @@ go_test(
         "@com_github_ethereum_go_ethereum//p2p/enr:go_default_library",
         "@com_github_golang_snappy//:go_default_library",
         "@com_github_libp2p_go_libp2p//:go_default_library",
+        "@com_github_libp2p_go_libp2p//core/connmgr:go_default_library",
         "@com_github_libp2p_go_libp2p//core/crypto:go_default_library",
         "@com_github_libp2p_go_libp2p//core/host:go_default_library",
         "@com_github_libp2p_go_libp2p//core/network:go_default_library",

beacon-chain/p2p/broadcaster.go

@@ -11,6 +11,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
 	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v6/config/params"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
 	"github.com/OffchainLabs/prysm/v6/crypto/hash"
 	"github.com/OffchainLabs/prysm/v6/monitoring/tracing"
@@ -308,19 +309,13 @@ func (s *Service) BroadcastLightClientFinalityUpdate(ctx context.Context, update
 // BroadcastDataColumnSidecar broadcasts a data column to the p2p network, the message is assumed to be
 // broadcasted to the current fork and to the input column subnet.
 func (s *Service) BroadcastDataColumnSidecar(
-	root [fieldparams.RootLength]byte,
 	dataColumnSubnet uint64,
-	dataColumnSidecar *ethpb.DataColumnSidecar,
+	dataColumnSidecar blocks.VerifiedRODataColumn,
 ) error {
 	// Add tracing to the function.
 	ctx, span := trace.StartSpan(s.ctx, "p2p.BroadcastDataColumnSidecar")
 	defer span.End()
 
-	// Ensure the data column sidecar is not nil.
-	if dataColumnSidecar == nil {
-		return errors.Errorf("attempted to broadcast nil data column sidecar at subnet %d", dataColumnSubnet)
-	}
-
 	// Retrieve the current fork digest.
 	forkDigest, err := s.currentForkDigest()
 	if err != nil {
@@ -330,16 +325,15 @@ func (s *Service) BroadcastDataColumnSidecar(
 	}
 
 	// Non-blocking broadcast, with attempts to discover a column subnet peer if none available.
-	go s.internalBroadcastDataColumnSidecar(ctx, root, dataColumnSubnet, dataColumnSidecar, forkDigest)
+	go s.internalBroadcastDataColumnSidecar(ctx, dataColumnSubnet, dataColumnSidecar, forkDigest)
 
 	return nil
 }
 
 func (s *Service) internalBroadcastDataColumnSidecar(
 	ctx context.Context,
-	root [fieldparams.RootLength]byte,
 	columnSubnet uint64,
-	dataColumnSidecar *ethpb.DataColumnSidecar,
+	dataColumnSidecar blocks.VerifiedRODataColumn,
 	forkDigest [fieldparams.VersionLength]byte,
 ) {
 	// Add tracing to the function.
@@ -385,8 +379,9 @@ func (s *Service) internalBroadcastDataColumnSidecar(
 	log.WithFields(logrus.Fields{
 		"slot":               slot,
 		"timeSinceSlotStart": time.Since(slotStartTime),
-		"root":               fmt.Sprintf("%#x", root),
+		"root":               fmt.Sprintf("%#x", dataColumnSidecar.BlockRoot()),
 		"columnSubnet":       columnSubnet,
+		"blobCount":          len(dataColumnSidecar.Column),
 	}).Debug("Broadcasted data column sidecar")
 
 	// Increase the number of successful broadcasts.

beacon-chain/p2p/broadcaster_test.go

@@ -711,13 +711,8 @@ func TestService_BroadcastDataColumn(t *testing.T) {
 	subnet := peerdas.ComputeSubnetForDataColumnSidecar(columnIndex)
 	topic := fmt.Sprintf(topicFormat, digest, subnet) + service.Encoding().ProtocolSuffix()
 
-	roSidecars, _ := util.CreateTestVerifiedRoDataColumnSidecars(t, []util.DataColumnParam{{Index: columnIndex}})
-	sidecar := roSidecars[0].DataColumnSidecar
-
-	// Attempt to broadcast nil object should fail.
-	var emptyRoot [fieldparams.RootLength]byte
-	err = service.BroadcastDataColumnSidecar(emptyRoot, subnet, nil)
-	require.ErrorContains(t, "attempted to broadcast nil", err)
+	_, verifiedRoSidecars := util.CreateTestVerifiedRoDataColumnSidecars(t, []util.DataColumnParam{{Index: columnIndex}})
+	verifiedRoSidecar := verifiedRoSidecars[0]
 
 	// Subscribe to the topic.
 	sub, err := p2.SubscribeToTopic(topic)
@@ -727,7 +722,7 @@ func TestService_BroadcastDataColumn(t *testing.T) {
 	time.Sleep(50 * time.Millisecond)
 
 	// Broadcast to peers and wait.
-	err = service.BroadcastDataColumnSidecar(emptyRoot, subnet, sidecar)
+	err = service.BroadcastDataColumnSidecar(subnet, verifiedRoSidecar)
 	require.NoError(t, err)
 
 	// Receive the message.
@@ -739,5 +734,5 @@ func TestService_BroadcastDataColumn(t *testing.T) {
 
 	var result ethpb.DataColumnSidecar
 	require.NoError(t, service.Encoding().DecodeGossip(msg.Data, &result))
-	require.DeepEqual(t, &result, sidecar)
+	require.DeepEqual(t, &result, verifiedRoSidecar)
 }