Fix ethspecify check

* Calculate max epoch and churn for slashing once

* calculate once for proposer and attester slashings

* changelog <3

* introduce struct

* check if err is nil in ProcessVoluntaryExits

* rename exitData to exitInfo and return from functions

* cleanup + tests

* cleanup after rebase

* Potuz's review

* pre-calculate total active balance

* remove `slashValidatorFunc` closure

* Avoid a second validator loop

    🤖 Generated with [Claude Code](https://claude.ai/code)

    Co-Authored-By: Claude <noreply@anthropic.com>

* remove balance parameter from slashing functions

---------

Co-authored-by: terence tsao <terence@prysmaticlabs.com>
Co-authored-by: potuz <potuz@prysmaticlabs.com>

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -1,6 +1,6 @@
 name: 🐞 Bug report
 description: Report a bug or problem with running Prysm
-labels: ["Bug"]
+type: "Bug"
 body:
   - type: markdown
     attributes:

.github/workflows/check-specrefs.yml

@@ -0,0 +1,43 @@
+name: Check Spec References
+on: [push, pull_request]
+
+jobs:
+  check-specrefs:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v4
+
+    - name: Check version consistency
+      run: |
+        WORKSPACE_VERSION=$(grep 'consensus_spec_version = ' WORKSPACE | sed 's/.*"\(.*\)"/\1/')
+        ETHSPECIFY_VERSION=$(grep '^version:' specrefs/.ethspecify.yml | sed 's/version: //')
+        if [ "$WORKSPACE_VERSION" != "$ETHSPECIFY_VERSION" ]; then
+          echo "Version mismatch between WORKSPACE and ethspecify"
+          echo "  WORKSPACE: $WORKSPACE_VERSION"
+          echo "  specrefs/.ethspecify.yml: $ETHSPECIFY_VERSION"
+          exit 1
+        else
+          echo "Versions match: $WORKSPACE_VERSION"
+        fi
+
+    - name: Install ethspecify
+      run: python3 -mpip install ethspecify
+
+    - name: Update spec references
+      run: ethspecify process --path=specrefs
+
+    - name: Check for differences
+      run: |
+        if ! git diff --exit-code specrefs >/dev/null; then
+          echo "Spec references are out-of-date!"
+          echo ""
+          git --no-pager diff specrefs
+          exit 1
+        else
+          echo "Spec references are up-to-date!"
+        fi
+
+    - name: Check spec references
+      run: ethspecify check --path=specrefs

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

@@ -253,16 +253,16 @@ filegroup(
     url = "https://github.com/ethereum/EIPs/archive/5480440fe51742ed23342b68cf106cefd427e39d.tar.gz",
 )
 
-consensus_spec_version = "v1.6.0-alpha.4"
+consensus_spec_version = "v1.6.0-alpha.6"
 
 load("@prysm//tools:download_spectests.bzl", "consensus_spec_tests")
 
 consensus_spec_tests(
     name = "consensus_spec_tests",
     flavors = {
-        "general": "sha256-MaN4zu3o0vWZypUHS5r4D8WzJF4wANoadM8qm6iyDs4=",
-        "minimal": "sha256-aZGNPp/bBvJgq3Wf6vyR0H6G3DOkbSuggEmOL4jEmtg=",
-        "mainnet": "sha256-C7jjosvpzUgw3GPajlsWBV02ZbkZ5Uv4ikmOqfDGajI=",
+        "general": "sha256-7wkWuahuCO37uVYnxq8Badvi+jY907pBj68ixL8XDOI=",
+        "minimal": "sha256-Qy/f27N0LffS/ej7VhIubwDejD6LMK0VdenKkqtZVt4=",
+        "mainnet": "sha256-3H7mu5yE+FGz2Wr/nc8Nd9aEu93YoEpsYtn0zBSoeDE=",
     },
     version = consensus_spec_version,
 )
@@ -278,7 +278,7 @@ filegroup(
     visibility = ["//visibility:public"],
 )
     """,
-    integrity = "sha256-qreawRS77l8CebiNww8z727qUItw7KlHY1Xqj7IrPdk=",
+    integrity = "sha256-uvz3XfMTGfy3/BtQQoEp5XQOgrWgcH/5Zo/gR0iiP+k=",
     strip_prefix = "consensus-specs-" + consensus_spec_version[1:],
     url = "https://github.com/ethereum/consensus-specs/archive/refs/tags/%s.tar.gz" % consensus_spec_version,
 )

api/server/httprest/options.go

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

beacon-chain/blockchain/kzg/kzg.go

@@ -102,7 +102,6 @@ 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

@@ -1,32 +1,14 @@
 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"
 )
 
-// Verify performs single or batch verification of commitments depending on the number of given BlobSidecars.
-func Verify(sidecars ...blocks.ROBlob) error {
-	if len(sidecars) == 0 {
-		return nil
-	}
-	if len(sidecars) == 1 {
-		return kzgContext.VerifyBlobKZGProof(
-			bytesToBlob(sidecars[0].Blob),
-			bytesToCommitment(sidecars[0].KzgCommitment),
-			bytesToKZGProof(sidecars[0].KzgProof))
-	}
-	blobs := make([]GoKZG.Blob, len(sidecars))
-	cmts := make([]GoKZG.KZGCommitment, len(sidecars))
-	proofs := make([]GoKZG.KZGProof, len(sidecars))
-	for i, sidecar := range sidecars {
-		blobs[i] = *bytesToBlob(sidecar.Blob)
-		cmts[i] = bytesToCommitment(sidecar.KzgCommitment)
-		proofs[i] = bytesToKZGProof(sidecar.KzgProof)
-	}
-	return kzgContext.VerifyBlobKZGProofBatch(blobs, cmts, proofs)
-}
-
 func bytesToBlob(blob []byte) *GoKZG.Blob {
 	var ret GoKZG.Blob
 	copy(ret[:], blob)
@@ -42,3 +24,144 @@ 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 {
+		return nil
+	}
+	if len(blobSidecars) == 1 {
+		return kzgContext.VerifyBlobKZGProof(
+			bytesToBlob(blobSidecars[0].Blob),
+			bytesToCommitment(blobSidecars[0].KzgCommitment),
+			bytesToKZGProof(blobSidecars[0].KzgProof))
+	}
+	blobs := make([]GoKZG.Blob, len(blobSidecars))
+	cmts := make([]GoKZG.KZGCommitment, len(blobSidecars))
+	proofs := make([]GoKZG.KZGProof, len(blobSidecars))
+	for i, sidecar := range blobSidecars {
+		blobs[i] = *bytesToBlob(sidecar.Blob)
+		cmts[i] = bytesToCommitment(sidecar.KzgCommitment)
+		proofs[i] = bytesToKZGProof(sidecar.KzgProof)
+	}
+	return kzgContext.VerifyBlobKZGProofBatch(blobs, cmts, proofs)
+}
+
+// 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
+}
+
+// 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
+
+	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

@@ -22,8 +22,8 @@ func GenerateCommitmentAndProof(blob GoKZG.Blob) (GoKZG.KZGCommitment, GoKZG.KZG
 }
 
 func TestVerify(t *testing.T) {
-	sidecars := make([]blocks.ROBlob, 0)
-	require.NoError(t, Verify(sidecars...))
+	blobSidecars := make([]blocks.ROBlob, 0)
+	require.NoError(t, Verify(blobSidecars...))
 }
 
 func TestBytesToAny(t *testing.T) {
@@ -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/process_block.go

@@ -159,7 +159,7 @@ 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")
 	}
 
@@ -240,9 +240,10 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []consensusblocks.ROBlo
 			}
 		}
 
-		if err := avs.IsDataAvailable(ctx, s.CurrentSlot(), b); err != nil {
-			return errors.Wrapf(err, "could not validate sidecar availability at slot %d", b.Block().Slot())
+		if err := s.areSidecarsAvailable(ctx, avs, b); err != nil {
+			return errors.Wrapf(err, "could not validate sidecar availability for block %#x at slot %d", b.Root(), b.Block().Slot())
 		}
+
 		args := &forkchoicetypes.BlockAndCheckpoints{Block: b,
 			JustifiedCheckpoint: jCheckpoints[i],
 			FinalizedCheckpoint: fCheckpoints[i]}
@@ -308,6 +309,30 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []consensusblocks.ROBlo
 	return s.saveHeadNoDB(ctx, lastB, lastBR, preState, !isValidPayload)
 }
 
+func (s *Service) areSidecarsAvailable(ctx context.Context, avs das.AvailabilityStore, roBlock consensusblocks.ROBlock) error {
+	blockVersion := roBlock.Version()
+	block := roBlock.Block()
+	slot := block.Slot()
+
+	if blockVersion >= version.Fulu {
+		if err := s.areDataColumnsAvailable(ctx, roBlock.Root(), block); err != nil {
+			return errors.Wrapf(err, "are data columns available for block %#x with slot %d", roBlock.Root(), slot)
+		}
+
+		return nil
+	}
+
+	if blockVersion >= version.Deneb {
+		if err := avs.IsDataAvailable(ctx, s.CurrentSlot(), roBlock); err != nil {
+			return errors.Wrapf(err, "could not validate sidecar availability at slot %d", slot)
+		}
+
+		return nil
+	}
+
+	return nil
+}
+
 func (s *Service) updateEpochBoundaryCaches(ctx context.Context, st state.BeaconState) error {
 	e := coreTime.CurrentEpoch(st)
 	if err := helpers.UpdateCommitteeCache(ctx, st, e); err != nil {

beacon-chain/blockchain/process_block_helpers.go

@@ -30,6 +30,10 @@ 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)
@@ -454,6 +458,9 @@ 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.

beacon-chain/blockchain/process_block_test.go

@@ -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

beacon-chain/blockchain/setup_forchoice.go

@@ -20,7 +20,7 @@ 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 +30,24 @@ 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)
 }

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)

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/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/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/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/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/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/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()
 
@@ -78,6 +110,7 @@ func TestIsCurrentEpochSyncCommittee_UsingCommittee(t *testing.T) {
 
 func TestIsCurrentEpochSyncCommittee_DoesNotExist(t *testing.T) {
 	helpers.ClearCache()
+	params.SetupTestConfigCleanup(t)
 
 	validators := make([]*ethpb.Validator, params.BeaconConfig().SyncCommitteeSize)
 	syncCommittee := &ethpb.SyncCommittee{
@@ -264,6 +297,7 @@ func TestCurrentEpochSyncSubcommitteeIndices_UsingCommittee(t *testing.T) {
 }
 
 func TestCurrentEpochSyncSubcommitteeIndices_DoesNotExist(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
 	helpers.ClearCache()
 
 	validators := make([]*ethpb.Validator, params.BeaconConfig().SyncCommitteeSize)

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/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/das/BUILD.bazel

@@ -4,7 +4,6 @@ go_library(
     name = "go_default_library",
     srcs = [
         "availability_blobs.go",
-        "availability_columns.go",
         "blob_cache.go",
         "data_column_cache.go",
         "iface.go",
@@ -13,7 +12,6 @@ go_library(
     importpath = "github.com/OffchainLabs/prysm/v6/beacon-chain/das",
     visibility = ["//visibility:public"],
     deps = [
-        "//beacon-chain/core/peerdas:go_default_library",
         "//beacon-chain/db/filesystem:go_default_library",
         "//beacon-chain/verification:go_default_library",
         "//config/fieldparams:go_default_library",
@@ -23,7 +21,6 @@ go_library(
         "//runtime/logging:go_default_library",
         "//runtime/version:go_default_library",
         "//time/slots:go_default_library",
-        "@com_github_ethereum_go_ethereum//p2p/enode:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
     ],
@@ -33,7 +30,6 @@ go_test(
     name = "go_default_test",
     srcs = [
         "availability_blobs_test.go",
-        "availability_columns_test.go",
         "blob_cache_test.go",
         "data_column_cache_test.go",
     ],
@@ -49,7 +45,6 @@ go_test(
         "//testing/require:go_default_library",
         "//testing/util:go_default_library",
         "//time/slots:go_default_library",
-        "@com_github_ethereum_go_ethereum//p2p/enode:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
     ],
 )

beacon-chain/das/availability_blobs.go

@@ -53,30 +53,25 @@ func NewLazilyPersistentStore(store *filesystem.BlobStorage, verifier BlobBatchV
 // Persist adds blobs to the working blob cache. Blobs stored in this cache will be persisted
 // for at least as long as the node is running. Once IsDataAvailable succeeds, all blobs referenced
 // by the given block are guaranteed to be persisted for the remainder of the retention period.
-func (s *LazilyPersistentStoreBlob) Persist(current primitives.Slot, sidecars ...blocks.ROSidecar) error {
+func (s *LazilyPersistentStoreBlob) Persist(current primitives.Slot, sidecars ...blocks.ROBlob) error {
 	if len(sidecars) == 0 {
 		return nil
 	}
 
-	blobSidecars, err := blocks.BlobSidecarsFromSidecars(sidecars)
-	if err != nil {
-		return errors.Wrap(err, "blob sidecars from sidecars")
-	}
-
-	if len(blobSidecars) > 1 {
-		firstRoot := blobSidecars[0].BlockRoot()
-		for _, sidecar := range blobSidecars[1:] {
+	if len(sidecars) > 1 {
+		firstRoot := sidecars[0].BlockRoot()
+		for _, sidecar := range sidecars[1:] {
 			if sidecar.BlockRoot() != firstRoot {
 				return errMixedRoots
 			}
 		}
 	}
-	if !params.WithinDAPeriod(slots.ToEpoch(blobSidecars[0].Slot()), slots.ToEpoch(current)) {
+	if !params.WithinDAPeriod(slots.ToEpoch(sidecars[0].Slot()), slots.ToEpoch(current)) {
 		return nil
 	}
-	key := keyFromSidecar(blobSidecars[0])
+	key := keyFromSidecar(sidecars[0])
 	entry := s.cache.ensure(key)
-	for _, blobSidecar := range blobSidecars {
+	for _, blobSidecar := range sidecars {
 		if err := entry.stash(&blobSidecar); err != nil {
 			return err
 		}

beacon-chain/das/availability_blobs_test.go

@@ -118,23 +118,21 @@ func TestLazilyPersistent_Missing(t *testing.T) {
 
 	blk, blobSidecars := util.GenerateTestDenebBlockWithSidecar(t, [32]byte{}, 1, 3)
 
-	scs := blocks.NewSidecarsFromBlobSidecars(blobSidecars)
-
 	mbv := &mockBlobBatchVerifier{t: t, scs: blobSidecars}
 	as := NewLazilyPersistentStore(store, mbv)
 
 	// Only one commitment persisted, should return error with other indices
-	require.NoError(t, as.Persist(1, scs[2]))
+	require.NoError(t, as.Persist(1, blobSidecars[2]))
 	err := as.IsDataAvailable(ctx, 1, blk)
 	require.ErrorIs(t, err, errMissingSidecar)
 
 	// All but one persisted, return missing idx
-	require.NoError(t, as.Persist(1, scs[0]))
+	require.NoError(t, as.Persist(1, blobSidecars[0]))
 	err = as.IsDataAvailable(ctx, 1, blk)
 	require.ErrorIs(t, err, errMissingSidecar)
 
 	// All persisted, return nil
-	require.NoError(t, as.Persist(1, scs...))
+	require.NoError(t, as.Persist(1, blobSidecars...))
 
 	require.NoError(t, as.IsDataAvailable(ctx, 1, blk))
 }
@@ -149,10 +147,8 @@ func TestLazilyPersistent_Mismatch(t *testing.T) {
 	blobSidecars[0].KzgCommitment = bytesutil.PadTo([]byte("nope"), 48)
 	as := NewLazilyPersistentStore(store, mbv)
 
-	scs := blocks.NewSidecarsFromBlobSidecars(blobSidecars)
-
 	// Only one commitment persisted, should return error with other indices
-	require.NoError(t, as.Persist(1, scs[0]))
+	require.NoError(t, as.Persist(1, blobSidecars[0]))
 	err := as.IsDataAvailable(ctx, 1, blk)
 	require.NotNil(t, err)
 	require.ErrorIs(t, err, errCommitmentMismatch)
@@ -161,29 +157,25 @@ func TestLazilyPersistent_Mismatch(t *testing.T) {
 func TestLazyPersistOnceCommitted(t *testing.T) {
 	_, blobSidecars := util.GenerateTestDenebBlockWithSidecar(t, [32]byte{}, 1, 6)
 
-	scs := blocks.NewSidecarsFromBlobSidecars(blobSidecars)
-
 	as := NewLazilyPersistentStore(filesystem.NewEphemeralBlobStorage(t), &mockBlobBatchVerifier{})
 	// stashes as expected
-	require.NoError(t, as.Persist(1, scs...))
+	require.NoError(t, as.Persist(1, blobSidecars...))
 	// ignores duplicates
-	require.ErrorIs(t, as.Persist(1, scs...), ErrDuplicateSidecar)
+	require.ErrorIs(t, as.Persist(1, blobSidecars...), ErrDuplicateSidecar)
 
 	// ignores index out of bound
 	blobSidecars[0].Index = 6
-	require.ErrorIs(t, as.Persist(1, blocks.NewSidecarFromBlobSidecar(blobSidecars[0])), errIndexOutOfBounds)
+	require.ErrorIs(t, as.Persist(1, blobSidecars[0]), errIndexOutOfBounds)
 
 	_, moreBlobSidecars := util.GenerateTestDenebBlockWithSidecar(t, [32]byte{}, 1, 4)
 
-	more := blocks.NewSidecarsFromBlobSidecars(moreBlobSidecars)
-
 	// ignores sidecars before the retention period
 	slotOOB, err := slots.EpochStart(params.BeaconConfig().MinEpochsForBlobsSidecarsRequest)
 	require.NoError(t, err)
-	require.NoError(t, as.Persist(32+slotOOB, more[0]))
+	require.NoError(t, as.Persist(32+slotOOB, moreBlobSidecars[0]))
 
 	// doesn't ignore new sidecars with a different block root
-	require.NoError(t, as.Persist(1, more...))
+	require.NoError(t, as.Persist(1, moreBlobSidecars...))
 }
 
 type mockBlobBatchVerifier struct {

beacon-chain/das/availability_columns.go

@@ -1,213 +0,0 @@
-package das
-
-import (
-	"context"
-
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filesystem"
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/verification"
-	"github.com/OffchainLabs/prysm/v6/config/params"
-	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
-	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
-	"github.com/OffchainLabs/prysm/v6/runtime/version"
-	"github.com/OffchainLabs/prysm/v6/time/slots"
-	"github.com/ethereum/go-ethereum/p2p/enode"
-	errors "github.com/pkg/errors"
-)
-
-// LazilyPersistentStoreColumn is an implementation of AvailabilityStore to be used when batch syncing data columns.
-// This implementation will hold any data columns passed to Persist until the IsDataAvailable is called for their
-// block, at which time they will undergo full verification and be saved to the disk.
-type LazilyPersistentStoreColumn struct {
-	store                  *filesystem.DataColumnStorage
-	nodeID                 enode.ID
-	cache                  *dataColumnCache
-	newDataColumnsVerifier verification.NewDataColumnsVerifier
-	custodyGroupCount      uint64
-}
-
-var _ AvailabilityStore = &LazilyPersistentStoreColumn{}
-
-// DataColumnsVerifier enables LazilyPersistentStoreColumn to manage the verification process
-// going from RODataColumn->VerifiedRODataColumn, while avoiding the decision of which individual verifications
-// to run and in what order. Since LazilyPersistentStoreColumn always tries to verify and save data columns only when
-// they are all available, the interface takes a slice of data column sidecars.
-type DataColumnsVerifier interface {
-	VerifiedRODataColumns(ctx context.Context, blk blocks.ROBlock, scs []blocks.RODataColumn) ([]blocks.VerifiedRODataColumn, error)
-}
-
-// NewLazilyPersistentStoreColumn creates a new LazilyPersistentStoreColumn.
-// WARNING: The resulting LazilyPersistentStoreColumn is NOT thread-safe.
-func NewLazilyPersistentStoreColumn(
-	store *filesystem.DataColumnStorage,
-	nodeID enode.ID,
-	newDataColumnsVerifier verification.NewDataColumnsVerifier,
-	custodyGroupCount uint64,
-) *LazilyPersistentStoreColumn {
-	return &LazilyPersistentStoreColumn{
-		store:                  store,
-		nodeID:                 nodeID,
-		cache:                  newDataColumnCache(),
-		newDataColumnsVerifier: newDataColumnsVerifier,
-		custodyGroupCount:      custodyGroupCount,
-	}
-}
-
-// PersistColumns adds columns to the working column cache. Columns stored in this cache will be persisted
-// for at least as long as the node is running. Once IsDataAvailable succeeds, all columns referenced
-// by the given block are guaranteed to be persisted for the remainder of the retention period.
-func (s *LazilyPersistentStoreColumn) Persist(current primitives.Slot, sidecars ...blocks.ROSidecar) error {
-	if len(sidecars) == 0 {
-		return nil
-	}
-
-	dataColumnSidecars, err := blocks.DataColumnSidecarsFromSidecars(sidecars)
-	if err != nil {
-		return errors.Wrap(err, "blob sidecars from sidecars")
-	}
-
-	// It is safe to retrieve the first sidecar.
-	firstSidecar := dataColumnSidecars[0]
-
-	if len(sidecars) > 1 {
-		firstRoot := firstSidecar.BlockRoot()
-		for _, sidecar := range dataColumnSidecars[1:] {
-			if sidecar.BlockRoot() != firstRoot {
-				return errMixedRoots
-			}
-		}
-	}
-
-	firstSidecarEpoch, currentEpoch := slots.ToEpoch(firstSidecar.Slot()), slots.ToEpoch(current)
-	if !params.WithinDAPeriod(firstSidecarEpoch, currentEpoch) {
-		return nil
-	}
-
-	key := cacheKey{slot: firstSidecar.Slot(), root: firstSidecar.BlockRoot()}
-	entry := s.cache.ensure(key)
-
-	for _, sidecar := range dataColumnSidecars {
-		if err := entry.stash(&sidecar); err != nil {
-			return errors.Wrap(err, "stash DataColumnSidecar")
-		}
-	}
-
-	return nil
-}
-
-// IsDataAvailable returns nil if all the commitments in the given block are persisted to the db and have been verified.
-// DataColumnsSidecars already in the db are assumed to have been previously verified against the block.
-func (s *LazilyPersistentStoreColumn) IsDataAvailable(ctx context.Context, currentSlot primitives.Slot, block blocks.ROBlock) error {
-	blockCommitments, err := s.fullCommitmentsToCheck(s.nodeID, block, currentSlot)
-	if err != nil {
-		return errors.Wrapf(err, "full commitments to check with block root `%#x` and current slot `%d`", block.Root(), currentSlot)
-	}
-
-	// Return early for blocks that do not have any commitments.
-	if blockCommitments.count() == 0 {
-		return nil
-	}
-
-	// Get the root of the block.
-	blockRoot := block.Root()
-
-	// Build the cache key for the block.
-	key := cacheKey{slot: block.Block().Slot(), root: blockRoot}
-
-	// Retrieve the cache entry for the block, or create an empty one if it doesn't exist.
-	entry := s.cache.ensure(key)
-
-	// Delete the cache entry for the block at the end.
-	defer s.cache.delete(key)
-
-	// Set the disk summary for the block in the cache entry.
-	entry.setDiskSummary(s.store.Summary(blockRoot))
-
-	// Verify we have all the expected sidecars, and fail fast if any are missing or inconsistent.
-	// We don't try to salvage problematic batches because this indicates a misbehaving peer and we'd rather
-	// ignore their response and decrease their peer score.
-	roDataColumns, err := entry.filter(blockRoot, blockCommitments)
-	if err != nil {
-		return errors.Wrap(err, "entry filter")
-	}
-
-	// https://github.com/ethereum/consensus-specs/blob/master/specs/fulu/p2p-interface.md#datacolumnsidecarsbyrange-v1
-	verifier := s.newDataColumnsVerifier(roDataColumns, verification.ByRangeRequestDataColumnSidecarRequirements)
-
-	if err := verifier.ValidFields(); err != nil {
-		return errors.Wrap(err, "valid fields")
-	}
-
-	if err := verifier.SidecarInclusionProven(); err != nil {
-		return errors.Wrap(err, "sidecar inclusion proven")
-	}
-
-	if err := verifier.SidecarKzgProofVerified(); err != nil {
-		return errors.Wrap(err, "sidecar KZG proof verified")
-	}
-
-	verifiedRoDataColumns, err := verifier.VerifiedRODataColumns()
-	if err != nil {
-		return errors.Wrap(err, "verified RO data columns - should never happen")
-	}
-
-	if err := s.store.Save(verifiedRoDataColumns); err != nil {
-		return errors.Wrap(err, "save data column sidecars")
-	}
-
-	return nil
-}
-
-// fullCommitmentsToCheck returns the commitments to check for a given block.
-func (s *LazilyPersistentStoreColumn) fullCommitmentsToCheck(nodeID enode.ID, block blocks.ROBlock, currentSlot primitives.Slot) (*safeCommitmentsArray, error) {
-	samplesPerSlot := params.BeaconConfig().SamplesPerSlot
-
-	// Return early for blocks that are pre-Fulu.
-	if block.Version() < version.Fulu {
-		return &safeCommitmentsArray{}, nil
-	}
-
-	// Compute the block epoch.
-	blockSlot := block.Block().Slot()
-	blockEpoch := slots.ToEpoch(blockSlot)
-
-	// Compute the current epoch.
-	currentEpoch := slots.ToEpoch(currentSlot)
-
-	// Return early if the request is out of the MIN_EPOCHS_FOR_DATA_COLUMN_SIDECARS_REQUESTS window.
-	if !params.WithinDAPeriod(blockEpoch, currentEpoch) {
-		return &safeCommitmentsArray{}, nil
-	}
-
-	// Retrieve the KZG commitments for the block.
-	kzgCommitments, err := block.Block().Body().BlobKzgCommitments()
-	if err != nil {
-		return nil, errors.Wrap(err, "blob KZG commitments")
-	}
-
-	// Return early if there are no commitments in the block.
-	if len(kzgCommitments) == 0 {
-		return &safeCommitmentsArray{}, nil
-	}
-
-	// Retrieve peer info.
-	samplingSize := max(s.custodyGroupCount, samplesPerSlot)
-	peerInfo, _, err := peerdas.Info(nodeID, samplingSize)
-	if err != nil {
-		return nil, errors.Wrap(err, "peer info")
-	}
-
-	// Create a safe commitments array for the custody columns.
-	commitmentsArray := &safeCommitmentsArray{}
-	commitmentsArraySize := uint64(len(commitmentsArray))
-
-	for column := range peerInfo.CustodyColumns {
-		if column >= commitmentsArraySize {
-			return nil, errors.Errorf("custody column index %d too high (max allowed %d) - should never happen", column, commitmentsArraySize)
-		}
-
-		commitmentsArray[column] = kzgCommitments
-	}
-
-	return commitmentsArray, nil
-}

beacon-chain/das/availability_columns_test.go

@@ -1,313 +0,0 @@
-package das
-
-import (
-	"context"
-	"testing"
-
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filesystem"
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/verification"
-	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"
-	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
-	"github.com/OffchainLabs/prysm/v6/testing/require"
-	"github.com/OffchainLabs/prysm/v6/testing/util"
-	"github.com/OffchainLabs/prysm/v6/time/slots"
-	"github.com/ethereum/go-ethereum/p2p/enode"
-)
-
-var commitments = [][]byte{
-	bytesutil.PadTo([]byte("a"), 48),
-	bytesutil.PadTo([]byte("b"), 48),
-	bytesutil.PadTo([]byte("c"), 48),
-	bytesutil.PadTo([]byte("d"), 48),
-}
-
-func TestPersist(t *testing.T) {
-	t.Run("no sidecars", func(t *testing.T) {
-		dataColumnStorage := filesystem.NewEphemeralDataColumnStorage(t)
-		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, enode.ID{}, nil, 0)
-		err := lazilyPersistentStoreColumns.Persist(0)
-		require.NoError(t, err)
-		require.Equal(t, 0, len(lazilyPersistentStoreColumns.cache.entries))
-	})
-
-	t.Run("mixed roots", func(t *testing.T) {
-		dataColumnStorage := filesystem.NewEphemeralDataColumnStorage(t)
-
-		dataColumnParamsByBlockRoot := []util.DataColumnParam{
-			{Slot: 1, Index: 1},
-			{Slot: 2, Index: 2},
-		}
-
-		roSidecars, _ := roSidecarsFromDataColumnParamsByBlockRoot(t, dataColumnParamsByBlockRoot)
-		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, enode.ID{}, nil, 0)
-
-		err := lazilyPersistentStoreColumns.Persist(0, roSidecars...)
-		require.ErrorIs(t, err, errMixedRoots)
-		require.Equal(t, 0, len(lazilyPersistentStoreColumns.cache.entries))
-	})
-
-	t.Run("outside DA period", func(t *testing.T) {
-		dataColumnStorage := filesystem.NewEphemeralDataColumnStorage(t)
-
-		dataColumnParamsByBlockRoot := []util.DataColumnParam{
-			{Slot: 1, Index: 1},
-		}
-
-		roSidecars, _ := roSidecarsFromDataColumnParamsByBlockRoot(t, dataColumnParamsByBlockRoot)
-		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, enode.ID{}, nil, 0)
-
-		err := lazilyPersistentStoreColumns.Persist(1_000_000, roSidecars...)
-		require.NoError(t, err)
-		require.Equal(t, 0, len(lazilyPersistentStoreColumns.cache.entries))
-	})
-
-	t.Run("nominal", func(t *testing.T) {
-		const slot = 42
-		dataColumnStorage := filesystem.NewEphemeralDataColumnStorage(t)
-
-		dataColumnParamsByBlockRoot := []util.DataColumnParam{
-			{Slot: slot, Index: 1},
-			{Slot: slot, Index: 5},
-		}
-
-		roSidecars, roDataColumns := roSidecarsFromDataColumnParamsByBlockRoot(t, dataColumnParamsByBlockRoot)
-		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, enode.ID{}, nil, 0)
-
-		err := lazilyPersistentStoreColumns.Persist(slot, roSidecars...)
-		require.NoError(t, err)
-		require.Equal(t, 1, len(lazilyPersistentStoreColumns.cache.entries))
-
-		key := cacheKey{slot: slot, root: roDataColumns[0].BlockRoot()}
-		entry, ok := lazilyPersistentStoreColumns.cache.entries[key]
-		require.Equal(t, true, ok)
-
-		// A call to Persist does NOT save the sidecars to disk.
-		require.Equal(t, uint64(0), entry.diskSummary.Count())
-
-		require.DeepSSZEqual(t, roDataColumns[0], *entry.scs[1])
-		require.DeepSSZEqual(t, roDataColumns[1], *entry.scs[5])
-
-		for i, roDataColumn := range entry.scs {
-			if map[int]bool{1: true, 5: true}[i] {
-				continue
-			}
-
-			require.IsNil(t, roDataColumn)
-		}
-	})
-}
-
-func TestIsDataAvailable(t *testing.T) {
-	newDataColumnsVerifier := func(dataColumnSidecars []blocks.RODataColumn, _ []verification.Requirement) verification.DataColumnsVerifier {
-		return &mockDataColumnsVerifier{t: t, dataColumnSidecars: dataColumnSidecars}
-	}
-
-	ctx := t.Context()
-
-	t.Run("without commitments", func(t *testing.T) {
-		signedBeaconBlockFulu := util.NewBeaconBlockFulu()
-		signedRoBlock := newSignedRoBlock(t, signedBeaconBlockFulu)
-
-		dataColumnStorage := filesystem.NewEphemeralDataColumnStorage(t)
-		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, enode.ID{}, newDataColumnsVerifier, 0)
-
-		err := lazilyPersistentStoreColumns.IsDataAvailable(ctx, 0 /*current slot*/, signedRoBlock)
-		require.NoError(t, err)
-	})
-
-	t.Run("with commitments", func(t *testing.T) {
-		signedBeaconBlockFulu := util.NewBeaconBlockFulu()
-		signedBeaconBlockFulu.Block.Body.BlobKzgCommitments = commitments
-		signedRoBlock := newSignedRoBlock(t, signedBeaconBlockFulu)
-		block := signedRoBlock.Block()
-		slot := block.Slot()
-		proposerIndex := block.ProposerIndex()
-		parentRoot := block.ParentRoot()
-		stateRoot := block.StateRoot()
-		bodyRoot, err := block.Body().HashTreeRoot()
-		require.NoError(t, err)
-
-		root := signedRoBlock.Root()
-
-		dataColumnStorage := filesystem.NewEphemeralDataColumnStorage(t)
-		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, enode.ID{}, newDataColumnsVerifier, 0)
-
-		indices := [...]uint64{1, 17, 19, 42, 75, 87, 102, 117}
-		dataColumnsParams := make([]util.DataColumnParam, 0, len(indices))
-		for _, index := range indices {
-			dataColumnParams := util.DataColumnParam{
-				Index:          index,
-				KzgCommitments: commitments,
-
-				Slot:          slot,
-				ProposerIndex: proposerIndex,
-				ParentRoot:    parentRoot[:],
-				StateRoot:     stateRoot[:],
-				BodyRoot:      bodyRoot[:],
-			}
-
-			dataColumnsParams = append(dataColumnsParams, dataColumnParams)
-		}
-
-		_, verifiedRoDataColumns := util.CreateTestVerifiedRoDataColumnSidecars(t, dataColumnsParams)
-
-		key := cacheKey{root: root}
-		entry := lazilyPersistentStoreColumns.cache.ensure(key)
-		defer lazilyPersistentStoreColumns.cache.delete(key)
-
-		for _, verifiedRoDataColumn := range verifiedRoDataColumns {
-			err := entry.stash(&verifiedRoDataColumn.RODataColumn)
-			require.NoError(t, err)
-		}
-
-		err = lazilyPersistentStoreColumns.IsDataAvailable(ctx, slot, signedRoBlock)
-		require.NoError(t, err)
-
-		actual, err := dataColumnStorage.Get(root, indices[:])
-		require.NoError(t, err)
-
-		summary := dataColumnStorage.Summary(root)
-		require.Equal(t, uint64(len(indices)), summary.Count())
-		require.DeepSSZEqual(t, verifiedRoDataColumns, actual)
-	})
-}
-
-func TestFullCommitmentsToCheck(t *testing.T) {
-	windowSlots, err := slots.EpochEnd(params.BeaconConfig().MinEpochsForDataColumnSidecarsRequest)
-	require.NoError(t, err)
-
-	testCases := []struct {
-		name        string
-		commitments [][]byte
-		block       func(*testing.T) blocks.ROBlock
-		slot        primitives.Slot
-	}{
-		{
-			name: "Pre-Fulu block",
-			block: func(t *testing.T) blocks.ROBlock {
-				return newSignedRoBlock(t, util.NewBeaconBlockElectra())
-			},
-		},
-		{
-			name: "Commitments outside data availability window",
-			block: func(t *testing.T) blocks.ROBlock {
-				beaconBlockElectra := util.NewBeaconBlockElectra()
-
-				// Block is from slot 0, "current slot" is window size +1 (so outside the window)
-				beaconBlockElectra.Block.Body.BlobKzgCommitments = commitments
-
-				return newSignedRoBlock(t, beaconBlockElectra)
-			},
-			slot: windowSlots + 1,
-		},
-		{
-			name: "Commitments within data availability window",
-			block: func(t *testing.T) blocks.ROBlock {
-				signedBeaconBlockFulu := util.NewBeaconBlockFulu()
-				signedBeaconBlockFulu.Block.Body.BlobKzgCommitments = commitments
-				signedBeaconBlockFulu.Block.Slot = 100
-
-				return newSignedRoBlock(t, signedBeaconBlockFulu)
-			},
-			commitments: commitments,
-			slot:        100,
-		},
-	}
-
-	for _, tc := range testCases {
-		t.Run(tc.name, func(t *testing.T) {
-			numberOfColumns := params.BeaconConfig().NumberOfColumns
-
-			b := tc.block(t)
-			s := NewLazilyPersistentStoreColumn(nil, enode.ID{}, nil, numberOfColumns)
-
-			commitmentsArray, err := s.fullCommitmentsToCheck(enode.ID{}, b, tc.slot)
-			require.NoError(t, err)
-
-			for _, commitments := range commitmentsArray {
-				require.DeepEqual(t, tc.commitments, commitments)
-			}
-		})
-	}
-}
-
-func roSidecarsFromDataColumnParamsByBlockRoot(t *testing.T, parameters []util.DataColumnParam) ([]blocks.ROSidecar, []blocks.RODataColumn) {
-	roDataColumns, _ := util.CreateTestVerifiedRoDataColumnSidecars(t, parameters)
-
-	roSidecars := make([]blocks.ROSidecar, 0, len(roDataColumns))
-	for _, roDataColumn := range roDataColumns {
-		roSidecars = append(roSidecars, blocks.NewSidecarFromDataColumnSidecar(roDataColumn))
-	}
-
-	return roSidecars, roDataColumns
-}
-
-func newSignedRoBlock(t *testing.T, signedBeaconBlock interface{}) blocks.ROBlock {
-	sb, err := blocks.NewSignedBeaconBlock(signedBeaconBlock)
-	require.NoError(t, err)
-
-	rb, err := blocks.NewROBlock(sb)
-	require.NoError(t, err)
-
-	return rb
-}
-
-type mockDataColumnsVerifier struct {
-	t                                                                        *testing.T
-	dataColumnSidecars                                                       []blocks.RODataColumn
-	validCalled, SidecarInclusionProvenCalled, SidecarKzgProofVerifiedCalled bool
-}
-
-var _ verification.DataColumnsVerifier = &mockDataColumnsVerifier{}
-
-func (m *mockDataColumnsVerifier) VerifiedRODataColumns() ([]blocks.VerifiedRODataColumn, error) {
-	require.Equal(m.t, true, m.validCalled && m.SidecarInclusionProvenCalled && m.SidecarKzgProofVerifiedCalled)
-
-	verifiedDataColumnSidecars := make([]blocks.VerifiedRODataColumn, 0, len(m.dataColumnSidecars))
-	for _, dataColumnSidecar := range m.dataColumnSidecars {
-		verifiedDataColumnSidecar := blocks.NewVerifiedRODataColumn(dataColumnSidecar)
-		verifiedDataColumnSidecars = append(verifiedDataColumnSidecars, verifiedDataColumnSidecar)
-	}
-
-	return verifiedDataColumnSidecars, nil
-}
-
-func (m *mockDataColumnsVerifier) SatisfyRequirement(verification.Requirement) {}
-
-func (m *mockDataColumnsVerifier) ValidFields() error {
-	m.validCalled = true
-	return nil
-}
-
-func (m *mockDataColumnsVerifier) CorrectSubnet(dataColumnSidecarSubTopic string, expectedTopics []string) error {
-	return nil
-}
-func (m *mockDataColumnsVerifier) NotFromFutureSlot() error                         { return nil }
-func (m *mockDataColumnsVerifier) SlotAboveFinalized() error                        { return nil }
-func (m *mockDataColumnsVerifier) ValidProposerSignature(ctx context.Context) error { return nil }
-
-func (m *mockDataColumnsVerifier) SidecarParentSeen(parentSeen func([fieldparams.RootLength]byte) bool) error {
-	return nil
-}
-
-func (m *mockDataColumnsVerifier) SidecarParentValid(badParent func([fieldparams.RootLength]byte) bool) error {
-	return nil
-}
-
-func (m *mockDataColumnsVerifier) SidecarParentSlotLower() error       { return nil }
-func (m *mockDataColumnsVerifier) SidecarDescendsFromFinalized() error { return nil }
-
-func (m *mockDataColumnsVerifier) SidecarInclusionProven() error {
-	m.SidecarInclusionProvenCalled = true
-	return nil
-}
-
-func (m *mockDataColumnsVerifier) SidecarKzgProofVerified() error {
-	m.SidecarKzgProofVerifiedCalled = true
-	return nil
-}
-
-func (m *mockDataColumnsVerifier) SidecarProposerExpected(ctx context.Context) error { return nil }

beacon-chain/das/iface.go

@@ -15,5 +15,5 @@ import (
 // durably persisted before returning a non-error value.
 type AvailabilityStore interface {
 	IsDataAvailable(ctx context.Context, current primitives.Slot, b blocks.ROBlock) error
-	Persist(current primitives.Slot, sc ...blocks.ROSidecar) error
+	Persist(current primitives.Slot, blobSidecar ...blocks.ROBlob) error
 }

beacon-chain/das/mock.go

@@ -5,13 +5,12 @@ import (
 
 	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
-	errors "github.com/pkg/errors"
 )
 
 // MockAvailabilityStore is an implementation of AvailabilityStore that can be used by other packages in tests.
 type MockAvailabilityStore struct {
 	VerifyAvailabilityCallback func(ctx context.Context, current primitives.Slot, b blocks.ROBlock) error
-	PersistBlobsCallback       func(current primitives.Slot, sc ...blocks.ROBlob) error
+	PersistBlobsCallback       func(current primitives.Slot, blobSidecar ...blocks.ROBlob) error
 }
 
 var _ AvailabilityStore = &MockAvailabilityStore{}
@@ -25,13 +24,9 @@ func (m *MockAvailabilityStore) IsDataAvailable(ctx context.Context, current pri
 }
 
 // Persist satisfies the corresponding method of the AvailabilityStore interface in a way that is useful for tests.
-func (m *MockAvailabilityStore) Persist(current primitives.Slot, sc ...blocks.ROSidecar) error {
-	blobSidecars, err := blocks.BlobSidecarsFromSidecars(sc)
-	if err != nil {
-		return errors.Wrap(err, "blob sidecars from sidecars")
-	}
+func (m *MockAvailabilityStore) Persist(current primitives.Slot, blobSidecar ...blocks.ROBlob) error {
 	if m.PersistBlobsCallback != nil {
-		return m.PersistBlobsCallback(current, blobSidecars...)
+		return m.PersistBlobsCallback(current, blobSidecar...)
 	}
 	return nil
 }

beacon-chain/db/filesystem/data_column.go

@@ -100,6 +100,14 @@ type (
 	}
 )
 
+// DataColumnStorageReader is an interface to read data column sidecars from the filesystem.
+type DataColumnStorageReader interface {
+	Summary(root [fieldparams.RootLength]byte) DataColumnStorageSummary
+	Get(root [fieldparams.RootLength]byte, indices []uint64) ([]blocks.VerifiedRODataColumn, error)
+}
+
+var _ DataColumnStorageReader = &DataColumnStorage{}
+
 // WithDataColumnBasePath is a required option that sets the base path of data column storage.
 func WithDataColumnBasePath(base string) DataColumnStorageOption {
 	return func(b *DataColumnStorage) error {

beacon-chain/db/filesystem/data_column_cache.go

@@ -84,12 +84,6 @@ func (s DataColumnStorageSummary) Stored() map[uint64]bool {
 	return stored
 }
 
-// DataColumnStorageSummarizer can be used to receive a summary of metadata about data columns on disk for a given root.
-// The DataColumnStorageSummary can be used to check which indices (if any) are available for a given block by root.
-type DataColumnStorageSummarizer interface {
-	Summary(root [fieldparams.RootLength]byte) DataColumnStorageSummary
-}
-
 type dataColumnStorageSummaryCache struct {
 	mu                 sync.RWMutex
 	dataColumnCount    float64
@@ -98,8 +92,6 @@ type dataColumnStorageSummaryCache struct {
 	cache              map[[fieldparams.RootLength]byte]DataColumnStorageSummary
 }
 
-var _ DataColumnStorageSummarizer = &dataColumnStorageSummaryCache{}
-
 func newDataColumnStorageSummaryCache() *dataColumnStorageSummaryCache {
 	return &dataColumnStorageSummaryCache{
 		cache:             make(map[[fieldparams.RootLength]byte]DataColumnStorageSummary),

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/mock.go

@@ -144,14 +144,3 @@ func NewEphemeralDataColumnStorageWithMocker(t testing.TB) (*DataColumnMocker, *
 	fs, dcs := NewEphemeralDataColumnStorageAndFs(t)
 	return &DataColumnMocker{fs: fs, dcs: dcs}, dcs
 }
-
-func NewMockDataColumnStorageSummarizer(t *testing.T, set map[[fieldparams.RootLength]byte][]uint64) DataColumnStorageSummarizer {
-	c := newDataColumnStorageSummaryCache()
-	for root, indices := range set {
-		if err := c.set(DataColumnsIdent{Root: root, Epoch: 0, Indices: indices}); err != nil {
-			t.Fatal(err)
-		}
-	}
-
-	return c
-}

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/iface/interface.go

@@ -115,6 +115,17 @@ type NoHeadAccessDatabase interface {
 	CleanUpDirtyStates(ctx context.Context, slotsPerArchivedPoint primitives.Slot) error
 	DeleteHistoricalDataBeforeSlot(ctx context.Context, slot primitives.Slot, batchSize int) (int, error)
 
+	// Genesis operations.
+	LoadGenesis(ctx context.Context, stateBytes []byte) error
+	SaveGenesisData(ctx context.Context, state state.BeaconState) error
+	EnsureEmbeddedGenesis(ctx context.Context) error
+
+	// Support for checkpoint sync and backfill.
+	SaveOriginCheckpointBlockRoot(ctx context.Context, blockRoot [32]byte) error
+	SaveOrigin(ctx context.Context, serState, serBlock []byte) error
+	SaveBackfillStatus(context.Context, *dbval.BackfillStatus) error
+	BackfillFinalizedIndex(ctx context.Context, blocks []blocks.ROBlock, finalizedChildRoot [32]byte) error
+
 	// Custody operations.
 	UpdateSubscribedToAllDataSubnets(ctx context.Context, subscribed bool) (bool, error)
 	UpdateCustodyInfo(ctx context.Context, earliestAvailableSlot primitives.Slot, custodyGroupCount uint64) (primitives.Slot, uint64, error)
@@ -131,16 +142,6 @@ type HeadAccessDatabase interface {
 	HeadBlock(ctx context.Context) (interfaces.ReadOnlySignedBeaconBlock, error)
 	HeadBlockRoot() ([32]byte, error)
 	SaveHeadBlockRoot(ctx context.Context, blockRoot [32]byte) error
-
-	// Genesis operations.
-	LoadGenesis(ctx context.Context, stateBytes []byte) error
-	SaveGenesisData(ctx context.Context, state state.BeaconState) error
-	EnsureEmbeddedGenesis(ctx context.Context) error
-
-	// Support for checkpoint sync and backfill.
-	SaveOrigin(ctx context.Context, serState, serBlock []byte) error
-	SaveBackfillStatus(context.Context, *dbval.BackfillStatus) error
-	BackfillFinalizedIndex(ctx context.Context, blocks []blocks.ROBlock, finalizedChildRoot [32]byte) error
 }
 
 // SlasherDatabase interface for persisting data related to detecting slashable offenses on Ethereum.

beacon-chain/node/node.go

@@ -318,6 +318,7 @@ func startBaseServices(cliCtx *cli.Context, beacon *BeaconNode, depositAddress s
 	}
 
 	beacon.BlobStorage.WarmCache()
+	beacon.DataColumnStorage.WarmCache()
 
 	log.Debugln("Starting Slashing DB")
 	if err := beacon.startSlasherDB(cliCtx, clearer); err != nil {
@@ -845,6 +846,7 @@ func (b *BeaconNode) registerInitialSyncService(complete chan struct{}) error {
 		ClockWaiter:         b.clockWaiter,
 		InitialSyncComplete: complete,
 		BlobStorage:         b.BlobStorage,
+		DataColumnStorage:   b.DataColumnStorage,
 	}, opts...)
 	return b.services.RegisterService(is)
 }
@@ -939,6 +941,7 @@ func (b *BeaconNode) registerRPCService(router *http.ServeMux) error {
 		FinalizationFetcher:       chainService,
 		BlockReceiver:             chainService,
 		BlobReceiver:              chainService,
+		DataColumnReceiver:        chainService,
 		AttestationReceiver:       chainService,
 		GenesisTimeFetcher:        chainService,
 		GenesisFetcher:            chainService,
@@ -966,6 +969,7 @@ func (b *BeaconNode) registerRPCService(router *http.ServeMux) error {
 		Router:                    router,
 		ClockWaiter:               b.clockWaiter,
 		BlobStorage:               b.BlobStorage,
+		DataColumnStorage:         b.DataColumnStorage,
 		TrackedValidatorsCache:    b.trackedValidatorsCache,
 		PayloadIDCache:            b.payloadIDCache,
 		LCStore:                   b.lcStore,

beacon-chain/p2p/BUILD.bazel

@@ -195,7 +195,6 @@ go_test(
         "@com_github_multiformats_go_multiaddr//:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
-        "@com_github_sirupsen_logrus//:go_default_library",
         "@com_github_sirupsen_logrus//hooks/test:go_default_library",
         "@org_golang_google_protobuf//proto:go_default_library",
     ],

beacon-chain/p2p/custody.go

@@ -155,6 +155,7 @@ func (s *Service) custodyGroupCountFromPeerENR(pid peer.ID) uint64 {
 	log := log.WithFields(logrus.Fields{
 		"peerID":       pid,
 		"defaultValue": custodyRequirement,
+		"agent":        agentString(pid, s.Host()),
 	})
 
 	// Retrieve the ENR of the peer.

beacon-chain/p2p/custody_test.go

@@ -8,6 +8,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/peers"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/peers/scorers"
+	testp2p "github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/testing"
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/wrapper"
@@ -269,6 +270,7 @@ func TestCustodyGroupCountFromPeer(t *testing.T) {
 			service := &Service{
 				peers:    peers,
 				metaData: tc.metadata,
+				host:     testp2p.NewTestP2P(t).Host(),
 			}
 
 			// Retrieve the custody count from the remote peer.
@@ -329,6 +331,7 @@ func TestCustodyGroupCountFromPeerENR(t *testing.T) {
 
 			service := &Service{
 				peers: peers,
+				host:  testp2p.NewTestP2P(t).Host(),
 			}
 
 			actual := service.custodyGroupCountFromPeerENR(pid)

beacon-chain/p2p/discovery.go

@@ -443,20 +443,27 @@ func (s *Service) findPeers(ctx context.Context, missingPeerCount uint) ([]*enod
 			return peersToDial, ctx.Err()
 		}
 
-		// Skip peer not matching the filter.
 		node := iterator.Node()
-		if !s.filterPeer(node) {
-			continue
-		}
 
 		// Remove duplicates, keeping the node with higher seq.
 		existing, ok := nodeByNodeID[node.ID()]
-		if ok && existing.Seq() > node.Seq() {
+		if ok && existing.Seq() >= node.Seq() {
+			continue // keep existing and skip.
+		}
+
+		// Treat nodes that exist in nodeByNodeID with higher seq numbers as new peers
+		// Skip peer not matching the filter.
+		if !s.filterPeer(node) {
+			if ok {
+				// this means the existing peer with the lower sequence number is no longer valid
+				delete(nodeByNodeID, existing.ID())
+				missingPeerCount++
+			}
 			continue
 		}
-		nodeByNodeID[node.ID()] = node
 
 		// We found a new peer. Decrease the missing peer count.
+		nodeByNodeID[node.ID()] = node
 		missingPeerCount--
 	}
 
@@ -677,7 +684,7 @@ func (s *Service) filterPeer(node *enode.Node) bool {
 
 	peerData, multiAddrs, err := convertToAddrInfo(node)
 	if err != nil {
-		log.WithError(err).Debug("Could not convert to peer data")
+		log.WithError(err).WithField("node", node.String()).Debug("Could not convert to peer data")
 		return false
 	}
 
@@ -844,7 +851,7 @@ func convertToMultiAddr(nodes []*enode.Node) []ma.Multiaddr {
 func convertToAddrInfo(node *enode.Node) (*peer.AddrInfo, []ma.Multiaddr, error) {
 	multiAddrs, err := retrieveMultiAddrsFromNode(node)
 	if err != nil {
-		return nil, nil, err
+		return nil, nil, errors.Wrap(err, "retrieve multiaddrs from node")
 	}
 
 	if len(multiAddrs) == 0 {

beacon-chain/p2p/discovery_test.go

@@ -1,9 +1,11 @@
 package p2p
 
 import (
+	"bytes"
 	"context"
 	"crypto/ecdsa"
 	"crypto/rand"
+	"crypto/sha256"
 	"fmt"
 	mathRand "math/rand"
 	"net"
@@ -58,6 +60,81 @@ func createAddrAndPrivKey(t *testing.T) (net.IP, *ecdsa.PrivateKey) {
 	return ipAddr, pkey
 }
 
+// createTestNodeWithID creates a LocalNode for testing with deterministic private key
+// This is needed for deduplication tests where we need the same node ID across different sequence numbers
+func createTestNodeWithID(t *testing.T, id string) *enode.LocalNode {
+	// Create a deterministic reader based on the ID for consistent key generation
+	h := sha256.New()
+	h.Write([]byte(id))
+	seedBytes := h.Sum(nil)
+
+	// Create a deterministic reader using the seed
+	deterministicReader := bytes.NewReader(seedBytes)
+
+	// Generate the private key using the same approach as the production code
+	privKey, _, err := crypto.GenerateSecp256k1Key(deterministicReader)
+	require.NoError(t, err)
+
+	// Convert to ECDSA private key for enode usage
+	ecdsaPrivKey, err := ecdsaprysm.ConvertFromInterfacePrivKey(privKey)
+	require.NoError(t, err)
+
+	db, err := enode.OpenDB("")
+	require.NoError(t, err)
+	t.Cleanup(func() { db.Close() })
+
+	localNode := enode.NewLocalNode(db, ecdsaPrivKey)
+
+	// Set basic properties
+	localNode.SetStaticIP(net.ParseIP("127.0.0.1"))
+	localNode.Set(enr.TCP(3000))
+	localNode.Set(enr.UDP(3000))
+	localNode.Set(enr.WithEntry(eth2EnrKey, make([]byte, 16)))
+
+	return localNode
+}
+
+// createTestNodeRandom creates a LocalNode for testing using the existing createAddrAndPrivKey function
+func createTestNodeRandom(t *testing.T) *enode.LocalNode {
+	_, privKey := createAddrAndPrivKey(t)
+
+	db, err := enode.OpenDB("")
+	require.NoError(t, err)
+	t.Cleanup(func() { db.Close() })
+
+	localNode := enode.NewLocalNode(db, privKey)
+
+	// Set basic properties
+	localNode.SetStaticIP(net.ParseIP("127.0.0.1"))
+	localNode.Set(enr.TCP(3000))
+	localNode.Set(enr.UDP(3000))
+	localNode.Set(enr.WithEntry(eth2EnrKey, make([]byte, 16)))
+
+	return localNode
+}
+
+// setNodeSeq updates a LocalNode to have the specified sequence number
+func setNodeSeq(localNode *enode.LocalNode, seq uint64) {
+	// Force set the sequence number - we need to update the record seq-1 times
+	// because it starts at 1
+	currentSeq := localNode.Node().Seq()
+	for currentSeq < seq {
+		localNode.Set(enr.WithEntry("dummy", currentSeq))
+		currentSeq++
+	}
+}
+
+// setNodeSubnets sets the attestation subnets for a LocalNode
+func setNodeSubnets(localNode *enode.LocalNode, attSubnets []uint64) {
+	if len(attSubnets) > 0 {
+		bitV := bitfield.NewBitvector64()
+		for _, subnet := range attSubnets {
+			bitV.SetBitAt(subnet, true)
+		}
+		localNode.Set(enr.WithEntry(attSubnetEnrKey, &bitV))
+	}
+}
+
 func TestCreateListener(t *testing.T) {
 	port := 1024
 	ipAddr, pkey := createAddrAndPrivKey(t)
@@ -241,7 +318,7 @@ func TestCreateLocalNode(t *testing.T) {
 
 			// Check fork is set.
 			fork := new([]byte)
-			require.NoError(t, localNode.Node().Record().Load(enr.WithEntry(eth2ENRKey, fork)))
+			require.NoError(t, localNode.Node().Record().Load(enr.WithEntry(eth2EnrKey, fork)))
 			require.NotEmpty(t, *fork)
 
 			// Check att subnets.
@@ -492,7 +569,7 @@ func TestMultipleDiscoveryAddresses(t *testing.T) {
 	node := enode.NewLocalNode(db, key)
 	node.Set(enr.IPv4{127, 0, 0, 1})
 	node.Set(enr.IPv6{0x20, 0x01, 0x48, 0x60, 0, 0, 0x20, 0x01, 0, 0, 0, 0, 0, 0, 0x00, 0x68})
-	s := &Service{dv5Listener: mockListener{localNode: node}}
+	s := &Service{dv5Listener: testp2p.NewMockListener(node, nil)}
 
 	multiAddresses, err := s.DiscoveryAddresses()
 	require.NoError(t, err)
@@ -517,7 +594,7 @@ func TestDiscoveryV5_SeqNumber(t *testing.T) {
 	node := enode.NewLocalNode(db, key)
 	node.Set(enr.IPv4{127, 0, 0, 1})
 	currentSeq := node.Seq()
-	s := &Service{dv5Listener: mockListener{localNode: node}}
+	s := &Service{dv5Listener: testp2p.NewMockListener(node, nil)}
 	_, err = s.DiscoveryAddresses()
 	require.NoError(t, err)
 	newSeq := node.Seq()
@@ -529,7 +606,7 @@ func TestDiscoveryV5_SeqNumber(t *testing.T) {
 	nodeTwo.Set(enr.IPv6{0x20, 0x01, 0x48, 0x60, 0, 0, 0x20, 0x01, 0, 0, 0, 0, 0, 0, 0x00, 0x68})
 	seqTwo := nodeTwo.Seq()
 	assert.NotEqual(t, seqTwo, newSeq)
-	sTwo := &Service{dv5Listener: mockListener{localNode: nodeTwo}}
+	sTwo := &Service{dv5Listener: testp2p.NewMockListener(nodeTwo, nil)}
 	_, err = sTwo.DiscoveryAddresses()
 	require.NoError(t, err)
 	assert.Equal(t, seqTwo+1, nodeTwo.Seq())
@@ -886,3 +963,289 @@ func TestRefreshPersistentSubnets(t *testing.T) {
 	// Reset the config.
 	params.OverrideBeaconConfig(defaultCfg)
 }
+
+func TestFindPeers_NodeDeduplication(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	cache.SubnetIDs.EmptyAllCaches()
+	defer cache.SubnetIDs.EmptyAllCaches()
+
+	ctx := t.Context()
+
+	// Create LocalNodes and manipulate sequence numbers
+	localNode1 := createTestNodeWithID(t, "node1")
+	localNode2 := createTestNodeWithID(t, "node2")
+	localNode3 := createTestNodeWithID(t, "node3")
+
+	// Create different sequence versions of node1
+	setNodeSeq(localNode1, 1)
+	node1_seq1 := localNode1.Node()
+	setNodeSeq(localNode1, 2)
+	node1_seq2 := localNode1.Node() // Same ID, higher seq
+	setNodeSeq(localNode1, 3)
+	node1_seq3 := localNode1.Node() // Same ID, even higher seq
+
+	// Other nodes with seq 1
+	node2_seq1 := localNode2.Node()
+	node3_seq1 := localNode3.Node()
+
+	tests := []struct {
+		name          string
+		nodes         []*enode.Node
+		missingPeers  uint
+		expectedCount int
+		description   string
+		eval          func(t *testing.T, result []*enode.Node)
+	}{
+		{
+			name: "No duplicates - all unique nodes",
+			nodes: []*enode.Node{
+				node2_seq1,
+				node3_seq1,
+			},
+			missingPeers:  2,
+			expectedCount: 2,
+			description:   "Should return all unique nodes without deduplication",
+			eval:          nil, // No special validation needed
+		},
+		{
+			name: "Duplicate with lower seq comes first - should replace",
+			nodes: []*enode.Node{
+				node1_seq1,
+				node1_seq2, // Higher seq, should replace
+				node2_seq1, // Different node added after duplicates are processed
+			},
+			missingPeers:  2, // Need 2 peers so we process all nodes
+			expectedCount: 2, // Should get node1 (with higher seq) and node2
+			description:   "Should keep node with higher sequence number when duplicate found",
+			eval: func(t *testing.T, result []*enode.Node) {
+				// Should have node2 and node1 with higher seq (node1_seq2)
+				foundNode1WithHigherSeq := false
+				for _, node := range result {
+					if node.ID() == node1_seq2.ID() {
+						require.Equal(t, node1_seq2.Seq(), node.Seq(), "Node1 should have higher seq")
+						foundNode1WithHigherSeq = true
+					}
+				}
+				require.Equal(t, true, foundNode1WithHigherSeq, "Should have node1 with higher seq")
+			},
+		},
+		{
+			name: "Duplicate with higher seq comes first - should keep existing",
+			nodes: []*enode.Node{
+				node1_seq3, // Higher seq
+				node1_seq2, // Lower seq, should be skipped (continue branch)
+				node1_seq1, // Even lower seq, should also be skipped (continue branch)
+				node2_seq1, // Different node added after duplicates are processed
+			},
+			missingPeers:  2,
+			expectedCount: 2,
+			description:   "Should keep existing node when it has higher sequence number and skip all lower seq duplicates",
+			eval: func(t *testing.T, result []*enode.Node) {
+				// Should have kept the node with highest seq (node1_seq3)
+				foundNode1WithHigherSeq := false
+				for _, node := range result {
+					if node.ID() == node1_seq3.ID() {
+						require.Equal(t, node1_seq3.Seq(), node.Seq(), "Node1 should have highest seq")
+						foundNode1WithHigherSeq = true
+					}
+				}
+				require.Equal(t, true, foundNode1WithHigherSeq, "Should have node1 with highest seq")
+			},
+		},
+		{
+			name: "Multiple duplicates with increasing seq",
+			nodes: []*enode.Node{
+				node1_seq1,
+				node1_seq2, // Should replace seq1
+				node1_seq3, // Should replace seq2
+				node2_seq1, // Different node added after duplicates are processed
+			},
+			missingPeers:  2,
+			expectedCount: 2,
+			description:   "Should keep updating to highest sequence number",
+			eval: func(t *testing.T, result []*enode.Node) {
+				// Should have the node with highest seq (node1_seq3)
+				foundNode1WithHigherSeq := false
+				for _, node := range result {
+					if node.ID() == node1_seq3.ID() {
+						require.Equal(t, node1_seq3.Seq(), node.Seq(), "Node1 should have highest seq")
+						foundNode1WithHigherSeq = true
+					}
+				}
+				require.Equal(t, true, foundNode1WithHigherSeq, "Should have node1 with highest seq")
+			},
+		},
+		{
+			name: "Duplicate with equal seq comes after - should skip",
+			nodes: []*enode.Node{
+				node1_seq2, // First occurrence
+				node1_seq2, // Same exact node instance, should be skipped (continue branch for >= case)
+				node2_seq1, // Different node
+			},
+			missingPeers:  2,
+			expectedCount: 2,
+			description:   "Should skip duplicate with equal sequence number",
+			eval: func(t *testing.T, result []*enode.Node) {
+				// Should have exactly one instance of node1_seq2 and one instance of node2_seq1
+				foundNode1 := false
+				foundNode2 := false
+				for _, node := range result {
+					if node.ID() == node1_seq2.ID() {
+						require.Equal(t, node1_seq2.Seq(), node.Seq(), "Node1 should have the expected seq")
+						require.Equal(t, false, foundNode1, "Should have only one instance of node1") // Ensure no duplicates
+						foundNode1 = true
+					}
+					if node.ID() == node2_seq1.ID() {
+						foundNode2 = true
+					}
+				}
+				require.Equal(t, true, foundNode1, "Should have node1")
+				require.Equal(t, true, foundNode2, "Should have node2")
+			},
+		},
+		{
+			name: "Mix of unique and duplicate nodes",
+			nodes: []*enode.Node{
+				node1_seq1,
+				node2_seq1,
+				node1_seq2, // Should replace node1_seq1
+				node3_seq1,
+				node1_seq3, // Should replace node1_seq2
+			},
+			missingPeers:  3,
+			expectedCount: 3,
+			description:   "Should handle mix of unique nodes and duplicates correctly",
+			eval:          nil, // Basic count validation is sufficient
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			fakePeer := testp2p.NewTestP2P(t)
+
+			s := &Service{
+				cfg: &Config{
+					MaxPeers: 30,
+				},
+				genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
+				peers: peers.NewStatus(ctx, &peers.StatusConfig{
+					PeerLimit:    30,
+					ScorerParams: &scorers.Config{},
+				}),
+				host: fakePeer.BHost,
+			}
+
+			localNode := createTestNodeRandom(t)
+			mockIter := testp2p.NewMockIterator(tt.nodes)
+			s.dv5Listener = testp2p.NewMockListener(localNode, mockIter)
+
+			ctxWithTimeout, cancel := context.WithTimeout(ctx, 1*time.Second)
+			defer cancel()
+
+			result, err := s.findPeers(ctxWithTimeout, tt.missingPeers)
+
+			require.NoError(t, err, tt.description)
+			require.Equal(t, tt.expectedCount, len(result), tt.description)
+
+			if tt.eval != nil {
+				tt.eval(t, result)
+			}
+		})
+	}
+}
+
+// callbackIterator allows us to execute callbacks at specific points during iteration
+type callbackIterator struct {
+	nodes     []*enode.Node
+	index     int
+	callbacks map[int]func() // map from index to callback function
+}
+
+func (c *callbackIterator) Next() bool {
+	// Execute callback before checking if we can continue (if one exists)
+	if callback, exists := c.callbacks[c.index]; exists {
+		callback()
+	}
+
+	return c.index < len(c.nodes)
+}
+
+func (c *callbackIterator) Node() *enode.Node {
+	if c.index >= len(c.nodes) {
+		return nil
+	}
+
+	node := c.nodes[c.index]
+	c.index++
+	return node
+}
+
+func (c *callbackIterator) Close() {
+	// Nothing to clean up for this simple implementation
+}
+
+func TestFindPeers_received_bad_existing_node(t *testing.T) {
+	// This test successfully triggers delete(nodeByNodeID, node.ID()) in subnets.go by:
+	// 1. Processing node1_seq1 first (passes filterPeer, gets added to map
+	// 2. Callback marks peer as bad before processing node1_seq2"
+	// 3. Processing node1_seq2 (fails filterPeer, triggers delete since ok=true
+	params.SetupTestConfigCleanup(t)
+	cache.SubnetIDs.EmptyAllCaches()
+	defer cache.SubnetIDs.EmptyAllCaches()
+
+	// Create LocalNode with same ID but different sequences
+	localNode1 := createTestNodeWithID(t, "testnode")
+	node1_seq1 := localNode1.Node() // Get current node
+	currentSeq := node1_seq1.Seq()
+	setNodeSeq(localNode1, currentSeq+1) // Increment sequence by 1
+	node1_seq2 := localNode1.Node()      // This should have higher seq
+
+	// Additional node to ensure we have enough peers to process
+	localNode2 := createTestNodeWithID(t, "othernode")
+	node2 := localNode2.Node()
+
+	fakePeer := testp2p.NewTestP2P(t)
+
+	service := &Service{
+		cfg: &Config{
+			MaxPeers: 30,
+		},
+		genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
+		peers: peers.NewStatus(t.Context(), &peers.StatusConfig{
+			PeerLimit:    30,
+			ScorerParams: &scorers.Config{},
+		}),
+		host: fakePeer.BHost,
+	}
+
+	// Create iterator with callback that marks peer as bad before processing node1_seq2
+	iter := &callbackIterator{
+		nodes: []*enode.Node{node1_seq1, node1_seq2, node2},
+		index: 0,
+		callbacks: map[int]func(){
+			1: func() { // Before processing node1_seq2 (index 1)
+				// Mark peer as bad before processing node1_seq2
+				peerData, _, _ := convertToAddrInfo(node1_seq2)
+				if peerData != nil {
+					service.peers.Add(node1_seq2.Record(), peerData.ID, nil, network.DirUnknown)
+					// Mark as bad peer - need enough increments to exceed threshold (6)
+					for i := 0; i < 10; i++ {
+						service.peers.Scorers().BadResponsesScorer().Increment(peerData.ID)
+					}
+				}
+			},
+		},
+	}
+
+	localNode := createTestNodeRandom(t)
+	service.dv5Listener = testp2p.NewMockListener(localNode, iter)
+
+	// Run findPeers - node1_seq1 gets processed first, then callback marks peer bad, then node1_seq2 fails
+	ctxWithTimeout, cancel := context.WithTimeout(t.Context(), 1*time.Second)
+	defer cancel()
+
+	result, err := service.findPeers(ctxWithTimeout, 3)
+
+	require.NoError(t, err)
+	require.Equal(t, 1, len(result))
+}

beacon-chain/p2p/fork.go

@@ -13,10 +13,17 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
-var errEth2ENRDigestMismatch = errors.New("fork digest of peer does not match local value")
+var (
+	errForkScheduleMismatch  = errors.New("peer fork schedule incompatible")
+	errCurrentDigestMismatch = errors.Wrap(errForkScheduleMismatch, "current_fork_digest mismatch")
+	errNextVersionMismatch   = errors.Wrap(errForkScheduleMismatch, "next_fork_version mismatch")
+	errNextDigestMismatch    = errors.Wrap(errForkScheduleMismatch, "nfd (next fork digest) mismatch")
+)
 
-// ENR key used for Ethereum consensus-related fork data.
-var eth2ENRKey = params.BeaconNetworkConfig().ETH2Key
+const (
+	eth2EnrKey = "eth2" // The `eth2` ENR entry advertizes the node's view of the fork schedule with an ssz-encoded ENRForkID value.
+	nfdEnrKey  = "nfd"  // The `nfd` ENR entry separately advertizes the "next fork digest" aspect of the fork schedule.
+)
 
 // ForkDigest returns the current fork digest of
 // the node according to the local clock.
@@ -33,44 +40,86 @@ func (s *Service) currentForkDigest() ([4]byte, error) {
 // Compares fork ENRs between an incoming peer's record and our node's
 // local record values for current and next fork version/epoch.
 func compareForkENR(self, peer *enr.Record) error {
-	peerForkENR, err := forkEntry(peer)
+	peerEntry, err := forkEntry(peer)
 	if err != nil {
 		return err
 	}
-	currentForkENR, err := forkEntry(self)
+	selfEntry, err := forkEntry(self)
 	if err != nil {
 		return err
 	}
-	enrString, err := SerializeENR(peer)
+	peerString, err := SerializeENR(peer)
 	if err != nil {
 		return err
 	}
 	// Clients SHOULD connect to peers with current_fork_digest, next_fork_version,
 	// and next_fork_epoch that match local values.
-	if !bytes.Equal(peerForkENR.CurrentForkDigest, currentForkENR.CurrentForkDigest) {
-		return errors.Wrapf(errEth2ENRDigestMismatch,
+	if !bytes.Equal(peerEntry.CurrentForkDigest, selfEntry.CurrentForkDigest) {
+		return errors.Wrapf(errCurrentDigestMismatch,
 			"fork digest of peer with ENR %s: %v, does not match local value: %v",
-			enrString,
-			peerForkENR.CurrentForkDigest,
-			currentForkENR.CurrentForkDigest,
+			peerString,
+			peerEntry.CurrentForkDigest,
+			selfEntry.CurrentForkDigest,
 		)
 	}
+
 	// Clients MAY connect to peers with the same current_fork_version but a
 	// different next_fork_version/next_fork_epoch. Unless ENRForkID is manually
 	// updated to matching prior to the earlier next_fork_epoch of the two clients,
 	// these type of connecting clients will be unable to successfully interact
 	// starting at the earlier next_fork_epoch.
-	if peerForkENR.NextForkEpoch != currentForkENR.NextForkEpoch {
+	if peerEntry.NextForkEpoch != selfEntry.NextForkEpoch {
 		log.WithFields(logrus.Fields{
-			"peerNextForkEpoch": peerForkENR.NextForkEpoch,
-			"peerENR":           enrString,
+			"peerNextForkEpoch":   peerEntry.NextForkEpoch,
+			"peerNextForkVersion": peerEntry.NextForkVersion,
+			"peerENR":             peerString,
 		}).Trace("Peer matches fork digest but has different next fork epoch")
+		// We allow the connection because we have a different view of the next fork epoch. This
+		// could be due to peers that have no upgraded ahead of a fork or BPO schedule change, so
+		// we allow the connection to continue until the fork boundary.
+		return nil
 	}
-	if !bytes.Equal(peerForkENR.NextForkVersion, currentForkENR.NextForkVersion) {
-		log.WithFields(logrus.Fields{
-			"peerNextForkVersion": peerForkENR.NextForkVersion,
-			"peerENR":             enrString,
-		}).Trace("Peer matches fork digest but has different next fork version")
+
+	// Since we agree on the next fork epoch, we require next fork version to also be in agreement.
+	if !bytes.Equal(peerEntry.NextForkVersion, selfEntry.NextForkVersion) {
+		return errors.Wrapf(errNextVersionMismatch,
+			"next fork version of peer with ENR %s: %#x, does not match local value: %#x",
+			peerString, peerEntry.NextForkVersion, selfEntry.NextForkVersion)
+	}
+
+	// Fulu adds the following to the spec:
+	// ---
+	// A new entry is added to the ENR under the key nfd, short for next fork digest. This entry
+	// communicates the digest of the next scheduled fork, regardless of whether it is a regular
+	// or a Blob-Parameters-Only fork. This new entry MUST be added once FULU_FORK_EPOCH is assigned
+	// any value other than FAR_FUTURE_EPOCH. Adding this entry prior to the Fulu fork will not
+	// impact peering as nodes will ignore unknown ENR entries and nfd mismatches do not cause
+	// disconnects.
+	// When discovering and interfacing with peers, nodes MUST evaluate nfd alongside their existing
+	// consideration of the ENRForkID::next_* fields under the eth2 key, to form a more accurate
+	// view of the peer's intended next fork for the purposes of sustained peering. If there is a
+	// mismatch, the node MUST NOT disconnect before the fork boundary, but it MAY disconnect
+	// at/after the fork boundary.
+
+	// Nodes unprepared to follow the Fulu fork will be unaware of nfd entries. However, their
+	// existing comparison of eth2 entries (concretely next_fork_epoch) is sufficient to detect
+	// upcoming divergence.
+	// ---
+
+	// Because this is a new in-bound connection, we lean into the pre-fulu point that clients
+	// MAY connect to peers with the same current_fork_version but a different
+	// next_fork_version/next_fork_epoch, which implies we can chose to not connect to them when these
+	// don't match.
+	//
+	// Given that the next_fork_epoch matches, we will require the next_fork_digest to match.
+	if !params.FuluEnabled() {
+		return nil
+	}
+	peerNFD, selfNFD := nfd(peer), nfd(self)
+	if peerNFD != selfNFD {
+		return errors.Wrapf(errNextDigestMismatch,
+			"next fork digest of peer with ENR %s: %v, does not match local value: %v",
+			peerString, peerNFD, selfNFD)
 	}
 	return nil
 }
@@ -102,7 +151,7 @@ func updateENR(node *enode.LocalNode, entry, next params.NetworkScheduleEntry) e
 	if err != nil {
 		return err
 	}
-	forkEntry := enr.WithEntry(eth2ENRKey, enc)
+	forkEntry := enr.WithEntry(eth2EnrKey, enc)
 	node.Set(forkEntry)
 	return nil
 }
@@ -111,7 +160,7 @@ func updateENR(node *enode.LocalNode, entry, next params.NetworkScheduleEntry) e
 // under the Ethereum consensus EnrKey
 func forkEntry(record *enr.Record) (*pb.ENRForkID, error) {
 	sszEncodedForkEntry := make([]byte, 16)
-	entry := enr.WithEntry(eth2ENRKey, &sszEncodedForkEntry)
+	entry := enr.WithEntry(eth2EnrKey, &sszEncodedForkEntry)
 	err := record.Load(entry)
 	if err != nil {
 		return nil, err
@@ -122,3 +171,15 @@ func forkEntry(record *enr.Record) (*pb.ENRForkID, error) {
 	}
 	return forkEntry, nil
 }
+
+// nfd retrieves the value of the `nfd` ("next fork digest") key from an ENR record.
+func nfd(record *enr.Record) [4]byte {
+	digest := [4]byte{}
+	entry := enr.WithEntry(nfdEnrKey, &digest)
+	if err := record.Load(entry); err != nil {
+		// Treat a missing nfd entry as an empty digest.
+		// We do this to avoid errors when checking peers that have not upgraded for fulu.
+		return [4]byte{}
+	}
+	return digest
+}

beacon-chain/p2p/fork_test.go

@@ -16,14 +16,12 @@ import (
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/p2p/enode"
 	"github.com/ethereum/go-ethereum/p2p/enr"
-	"github.com/sirupsen/logrus"
-	logTest "github.com/sirupsen/logrus/hooks/test"
 )
 
 func TestCompareForkENR(t *testing.T) {
 	params.SetupTestConfigCleanup(t)
+	params.BeaconConfig().FuluForkEpoch = params.BeaconConfig().ElectraForkEpoch + 4096
 	params.BeaconConfig().InitializeForkSchedule()
-	logrus.SetLevel(logrus.TraceLevel)
 
 	db, err := enode.OpenDB("")
 	assert.NoError(t, err)
@@ -61,10 +59,10 @@ func TestCompareForkENR(t *testing.T) {
 				require.NoError(t, updateENR(peer, currentCopy, next))
 				return peer.Node()
 			},
-			expectErr: errEth2ENRDigestMismatch,
+			expectErr: errCurrentDigestMismatch,
 		},
 		{
-			name: "next fork version mismatch",
+			name: "next_fork_epoch match, next_fork_version mismatch",
 			node: func(t *testing.T) *enode.Node {
 				// Create a peer with the same current fork digest and next fork version/epoch.
 				peer := enode.NewLocalNode(db, k)
@@ -75,25 +73,44 @@ func TestCompareForkENR(t *testing.T) {
 				require.NoError(t, updateENR(peer, current, nextCopy))
 				return peer.Node()
 			},
-			expectLog: "Peer matches fork digest but has different next fork version",
+			expectErr: errNextVersionMismatch,
 		},
 		{
-			name: "next fork epoch mismatch",
+			name: "next fork epoch mismatch, next fork digest mismatch",
 			node: func(t *testing.T) *enode.Node {
 				// Create a peer with the same current fork digest and next fork version/epoch.
 				peer := enode.NewLocalNode(db, k)
 				nextCopy := next
+				// next epoch does not match, and neither does the next fork digest.
 				nextCopy.Epoch = nextCopy.Epoch + 1
+				nfd := [4]byte{0xFF, 0xFF, 0xFF, 0xFF}
+				require.NotEqual(t, next.ForkDigest, nfd)
+				//peer.Set(enr.WithEntry(nfdEnrKey, nfd[:]))
+				nextCopy.ForkDigest = nfd
 				require.NoError(t, updateENR(peer, current, nextCopy))
 				return peer.Node()
 			},
-			expectLog: "Peer matches fork digest but has different next fork epoch",
+			// no error because we allow a different next fork version / digest if the next fork epoch does not match
+		},
+		{
+			name: "next fork epoch -match-, next fork digest mismatch",
+			node: func(t *testing.T) *enode.Node {
+				peer := enode.NewLocalNode(db, k)
+				nextCopy := next
+				nfd := [4]byte{0xFF, 0xFF, 0xFF, 0xFF}
+				// next epoch *does match*, but the next fork digest doesn't - so we should get an error.
+				require.NotEqual(t, next.ForkDigest, nfd)
+				nextCopy.ForkDigest = nfd
+				//peer.Set(enr.WithEntry(nfdEnrKey, nfd[:]))
+				require.NoError(t, updateENR(peer, current, nextCopy))
+				return peer.Node()
+			},
+			expectErr: errNextDigestMismatch,
 		},
 	}
 
 	for _, c := range cases {
 		t.Run(c.name, func(t *testing.T) {
-			hook := logTest.NewGlobal()
 			peer := c.node(t)
 			err := compareForkENR(self.Node().Record(), peer.Record())
 			if c.expectErr != nil {
@@ -101,13 +118,27 @@ func TestCompareForkENR(t *testing.T) {
 			} else {
 				require.NoError(t, err, "Expected no error comparing fork ENRs")
 			}
-			if c.expectLog != "" {
-				require.LogsContain(t, hook, c.expectLog, "Expected log message not found")
-			}
 		})
 	}
 }
 
+func TestNfdSetAndLoad(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	params.BeaconConfig().FuluForkEpoch = params.BeaconConfig().ElectraForkEpoch + 4096
+	params.BeaconConfig().InitializeForkSchedule()
+	db, err := enode.OpenDB("")
+	assert.NoError(t, err)
+	_, k := createAddrAndPrivKey(t)
+	clock := startup.NewClock(time.Now(), params.BeaconConfig().GenesisValidatorsRoot)
+	current := params.GetNetworkScheduleEntry(clock.CurrentEpoch())
+	next := params.NextNetworkScheduleEntry(clock.CurrentEpoch())
+	next.ForkDigest = [4]byte{0xFF, 0xFF, 0xFF, 0xFF} // Ensure a unique digest for testing.
+	self := enode.NewLocalNode(db, k)
+	require.NoError(t, updateENR(self, current, next))
+	n := nfd(self.Node().Record())
+	assert.Equal(t, next.ForkDigest, n, "Expected nfd to match next fork digest")
+}
+
 func TestDiscv5_AddRetrieveForkEntryENR(t *testing.T) {
 	params.SetupTestConfigCleanup(t)
 	params.BeaconConfig().InitializeForkSchedule()
@@ -122,7 +153,7 @@ func TestDiscv5_AddRetrieveForkEntryENR(t *testing.T) {
 	}
 	enc, err := enrForkID.MarshalSSZ()
 	require.NoError(t, err)
-	entry := enr.WithEntry(eth2ENRKey, enc)
+	entry := enr.WithEntry(eth2EnrKey, enc)
 	temp := t.TempDir()
 	randNum := rand.Int()
 	tempPath := path.Join(temp, strconv.Itoa(randNum))

beacon-chain/p2p/monitoring.go

@@ -18,6 +18,7 @@ var (
 		"lodestar",
 		"js-libp2p",
 		"rust-libp2p",
+		"erigon/caplin",
 	}
 	p2pPeerCount = promauto.NewGaugeVec(prometheus.GaugeOpts{
 		Name: "p2p_peer_count",

beacon-chain/p2p/peers/scorers/gossip_scorer_test.go

@@ -42,7 +42,7 @@ func TestScorers_Gossip_Score(t *testing.T) {
 			},
 			check: func(scorer *scorers.GossipScorer) {
 				assert.Equal(t, 10.0, scorer.Score("peer1"), "Unexpected score")
-				assert.Equal(t, nil, scorer.IsBadPeer("peer1"), "Unexpected bad peer")
+				assert.NoError(t, scorer.IsBadPeer("peer1"), "Unexpected bad peer")
 				_, _, topicMap, err := scorer.GossipData("peer1")
 				assert.NoError(t, err)
 				assert.Equal(t, uint64(100), topicMap["a"].TimeInMesh, "incorrect time in mesh")

beacon-chain/p2p/pubsub_filter.go

@@ -10,6 +10,7 @@ import (
 	pubsub "github.com/libp2p/go-libp2p-pubsub"
 	pubsubpb "github.com/libp2p/go-libp2p-pubsub/pb"
 	"github.com/libp2p/go-libp2p/core/peer"
+	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
 )
 
@@ -40,49 +41,68 @@ func (s *Service) setAllForkDigests() {
 	}
 }
 
+var (
+	errNotReadyToSubscribe         = fmt.Errorf("not ready to subscribe, service is not initialized")
+	errMissingLeadingSlash         = fmt.Errorf("topic is missing leading slash")
+	errTopicMissingProtocolVersion = fmt.Errorf("topic is missing protocol version (eth2)")
+	errTopicPathWrongPartCount     = fmt.Errorf("topic path has wrong part count")
+	errDigestInvalid               = fmt.Errorf("digest is invalid")
+	errDigestUnexpected            = fmt.Errorf("digest is unexpected")
+	errSnappySuffixMissing         = fmt.Errorf("snappy suffix is missing")
+	errTopicNotFound               = fmt.Errorf("topic not found in gossip topic mappings")
+)
+
 // CanSubscribe returns true if the topic is of interest and we could subscribe to it.
 func (s *Service) CanSubscribe(topic string) bool {
-	if !s.isInitialized() {
+	if err := s.checkSubscribable(topic); err != nil {
+		if !errors.Is(err, errNotReadyToSubscribe) {
+			logrus.WithError(err).WithField("topic", topic).Debug("CanSubscribe failed")
+		}
 		return false
 	}
+	return true
+}
+
+func (s *Service) checkSubscribable(topic string) error {
+	if !s.isInitialized() {
+		return errNotReadyToSubscribe
+	}
 	parts := strings.Split(topic, "/")
 	if len(parts) != 5 {
-		return false
+		return errTopicPathWrongPartCount
 	}
 	// The topic must start with a slash, which means the first part will be empty.
 	if parts[0] != "" {
-		return false
+		return errMissingLeadingSlash
 	}
-	if parts[1] != "eth2" {
-		return false
+	protocol, rawDigest, suffix := parts[1], parts[2], parts[4]
+	if protocol != "eth2" {
+		return errTopicMissingProtocolVersion
+	}
+	if suffix != encoder.ProtocolSuffixSSZSnappy {
+		return errSnappySuffixMissing
 	}
 
 	var digest [4]byte
-	dl, err := hex.Decode(digest[:], []byte(parts[2]))
-	if err == nil && dl != 4 {
-		err = fmt.Errorf("expected 4 bytes, got %d", dl)
-	}
+	dl, err := hex.Decode(digest[:], []byte(rawDigest))
 	if err != nil {
-		log.WithError(err).WithField("topic", topic).WithField("digest", parts[2]).Error("CanSubscribe failed to parse message")
-		return false
+		return errors.Wrapf(errDigestInvalid, "%v", err)
+	}
+	if dl != 4 {
+		return errors.Wrapf(errDigestInvalid, "wrong byte length")
 	}
 	if _, ok := s.allForkDigests[digest]; !ok {
-		log.WithField("topic", topic).WithField("digest", fmt.Sprintf("%#x", digest)).Error("CanSubscribe failed to find digest in allForkDigests")
-		return false
-	}
-
-	if parts[4] != encoder.ProtocolSuffixSSZSnappy {
-		return false
+		return errDigestUnexpected
 	}
 
 	// Check the incoming topic matches any topic mapping. This includes a check for part[3].
 	for gt := range gossipTopicMappings {
 		if _, err := scanfcheck(strings.Join(parts[0:4], "/"), gt); err == nil {
-			return true
+			return nil
 		}
 	}
 
-	return false
+	return errTopicNotFound
 }
 
 // FilterIncomingSubscriptions is invoked for all RPCs containing subscription notifications.
@@ -100,7 +120,22 @@ func (s *Service) FilterIncomingSubscriptions(peerID peer.ID, subs []*pubsubpb.R
 		return nil, pubsub.ErrTooManySubscriptions
 	}
 
-	return pubsub.FilterSubscriptions(subs, s.CanSubscribe), nil
+	return pubsub.FilterSubscriptions(subs, s.logCheckSubscribableError(peerID)), nil
+}
+
+func (s *Service) logCheckSubscribableError(pid peer.ID) func(string) bool {
+	return func(topic string) bool {
+		if err := s.checkSubscribable(topic); err != nil {
+			if !errors.Is(err, errNotReadyToSubscribe) {
+				log.WithError(err).WithFields(logrus.Fields{
+					"peerID": pid,
+					"topic":  topic,
+				}).Debug("Peer subscription rejected")
+			}
+			return false
+		}
+		return true
+	}
 }
 
 // scanfcheck uses fmt.Sscanf to check that a given string matches expected format. This method

beacon-chain/p2p/rpc_topic_mappings.go

@@ -169,7 +169,7 @@ var (
 		RPCDataColumnSidecarsByRangeTopicV1: new(pb.DataColumnSidecarsByRangeRequest),
 
 		// DataColumnSidecarsByRoot v1 Message
-		RPCDataColumnSidecarsByRootTopicV1: new(p2ptypes.DataColumnsByRootIdentifiers),
+		RPCDataColumnSidecarsByRootTopicV1: p2ptypes.DataColumnsByRootIdentifiers{},
 	}
 
 	// Maps all registered protocol prefixes.

beacon-chain/p2p/service_test.go

@@ -13,13 +13,13 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/encoder"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/peers"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/peers/scorers"
+	testp2p "github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/testing"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/startup"
 	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/testing/assert"
 	"github.com/OffchainLabs/prysm/v6/testing/require"
 	prysmTime "github.com/OffchainLabs/prysm/v6/time"
-	"github.com/ethereum/go-ethereum/p2p/enode"
 	"github.com/libp2p/go-libp2p"
 	"github.com/libp2p/go-libp2p/core/host"
 	"github.com/libp2p/go-libp2p/core/peer"
@@ -30,48 +30,6 @@ import (
 
 const testPingInterval = 100 * time.Millisecond
 
-type mockListener struct {
-	localNode *enode.LocalNode
-}
-
-func (m mockListener) Self() *enode.Node {
-	return m.localNode.Node()
-}
-
-func (mockListener) Close() {
-	// no-op
-}
-
-func (mockListener) Lookup(enode.ID) []*enode.Node {
-	panic("implement me")
-}
-
-func (mockListener) ReadRandomNodes(_ []*enode.Node) int {
-	panic("implement me")
-}
-
-func (mockListener) Resolve(*enode.Node) *enode.Node {
-	panic("implement me")
-}
-
-func (mockListener) Ping(*enode.Node) error {
-	panic("implement me")
-}
-
-func (mockListener) RequestENR(*enode.Node) (*enode.Node, error) {
-	panic("implement me")
-}
-
-func (mockListener) LocalNode() *enode.LocalNode {
-	panic("implement me")
-}
-
-func (mockListener) RandomNodes() enode.Iterator {
-	panic("implement me")
-}
-
-func (mockListener) RebootListener() error { panic("implement me") }
-
 func createHost(t *testing.T, port uint) (host.Host, *ecdsa.PrivateKey, net.IP) {
 	_, pkey := createAddrAndPrivKey(t)
 	ipAddr := net.ParseIP("127.0.0.1")
@@ -87,7 +45,7 @@ func TestService_Stop_SetsStartedToFalse(t *testing.T) {
 	s, err := NewService(t.Context(), &Config{StateNotifier: &mock.MockStateNotifier{}, DB: testDB.SetupDB(t)})
 	require.NoError(t, err)
 	s.started = true
-	s.dv5Listener = &mockListener{}
+	s.dv5Listener = testp2p.NewMockListener(nil, nil)
 	assert.NoError(t, s.Stop())
 	assert.Equal(t, false, s.started)
 }
@@ -113,7 +71,7 @@ func TestService_Start_OnlyStartsOnce(t *testing.T) {
 	}
 	s, err := NewService(t.Context(), cfg)
 	require.NoError(t, err)
-	s.dv5Listener = &mockListener{}
+	s.dv5Listener = testp2p.NewMockListener(nil, nil)
 	s.custodyInfo = &custodyInfo{}
 	exitRoutine := make(chan bool)
 	go func() {
@@ -133,14 +91,14 @@ func TestService_Start_OnlyStartsOnce(t *testing.T) {
 func TestService_Status_NotRunning(t *testing.T) {
 	params.SetupTestConfigCleanup(t)
 	s := &Service{started: false}
-	s.dv5Listener = &mockListener{}
+	s.dv5Listener = testp2p.NewMockListener(nil, nil)
 	assert.ErrorContains(t, "not running", s.Status(), "Status returned wrong error")
 }
 
 func TestService_Status_NoGenesisTimeSet(t *testing.T) {
 	params.SetupTestConfigCleanup(t)
 	s := &Service{started: true}
-	s.dv5Listener = &mockListener{}
+	s.dv5Listener = testp2p.NewMockListener(nil, nil)
 	assert.ErrorContains(t, "no genesis time set", s.Status(), "Status returned wrong error")
 
 	s.genesisTime = time.Now()

beacon-chain/p2p/subnets.go

@@ -27,8 +27,6 @@ import (
 	"github.com/prysmaticlabs/go-bitfield"
 )
 
-const nfdEnrKey = "nfd" // The ENR record key for "nfd" (Next Fork Digest).
-
 var (
 	attestationSubnetCount = params.BeaconConfig().AttestationSubnetCount
 	syncCommsSubnetCount   = params.BeaconConfig().SyncCommitteeSubnetCount
@@ -136,6 +134,24 @@ func (s *Service) FindAndDialPeersWithSubnets(
 	return nil
 }
 
+// updateDefectiveSubnets updates the defective subnets map when a node with matching subnets is found.
+// It decrements the defective count for each subnet the node satisfies and removes subnets
+// that are fully satisfied (count reaches 0).
+func updateDefectiveSubnets(
+	nodeSubnets map[uint64]bool,
+	defectiveSubnets map[uint64]int,
+) {
+	for subnet := range defectiveSubnets {
+		if !nodeSubnets[subnet] {
+			continue
+		}
+		defectiveSubnets[subnet]--
+		if defectiveSubnets[subnet] == 0 {
+			delete(defectiveSubnets, subnet)
+		}
+	}
+}
+
 // findPeersWithSubnets finds peers subscribed to defective subnets in batches
 // until enough peers are found or the context is canceled.
 // It returns new peers found during the search.
@@ -171,6 +187,7 @@ func (s *Service) findPeersWithSubnets(
 
 	// Crawl the network for peers subscribed to the defective subnets.
 	nodeByNodeID := make(map[enode.ID]*enode.Node)
+
 	for len(defectiveSubnets) > 0 && iterator.Next() {
 		if err := ctx.Err(); err != nil {
 			// Convert the map to a slice.
@@ -182,14 +199,28 @@ func (s *Service) findPeersWithSubnets(
 			return peersToDial, err
 		}
 
-		// Get all needed subnets that the node is subscribed to.
-		// Skip nodes that are not subscribed to any of the defective subnets.
 		node := iterator.Node()
 
+		// Remove duplicates, keeping the node with higher seq.
+		existing, ok := nodeByNodeID[node.ID()]
+		if ok && existing.Seq() >= node.Seq() {
+			continue // keep existing and skip.
+		}
+
+		// Treat nodes that exist in nodeByNodeID with higher seq numbers as new peers
+		// Skip peer not matching the filter.
 		if !s.filterPeer(node) {
+			if ok {
+				// this means the existing peer with the lower sequence number is no longer valid
+				delete(nodeByNodeID, existing.ID())
+				// Note: We are choosing to not rollback changes to the defective subnets map in favor of calling s.defectiveSubnets once again after dialing peers.
+				// This is a case that should rarely happen and should be handled through a second iteration in FindAndDialPeersWithSubnets
+			}
 			continue
 		}
 
+		// Get all needed subnets that the node is subscribed to.
+		// Skip nodes that are not subscribed to any of the defective subnets.
 		nodeSubnets, err := filter(node)
 		if err != nil {
 			return nil, errors.Wrap(err, "filter node")
@@ -198,30 +229,14 @@ func (s *Service) findPeersWithSubnets(
 			continue
 		}
 
-		// Remove duplicates, keeping the node with higher seq.
-		existing, ok := nodeByNodeID[node.ID()]
-		if ok && existing.Seq() > node.Seq() {
-			continue
-		}
-		nodeByNodeID[node.ID()] = node
-
 		// We found a new peer. Modify the defective subnets map
 		// and the filter accordingly.
-		for subnet := range defectiveSubnets {
-			if !nodeSubnets[subnet] {
-				continue
-			}
+		nodeByNodeID[node.ID()] = node
 
-			defectiveSubnets[subnet]--
-
-			if defectiveSubnets[subnet] == 0 {
-				delete(defectiveSubnets, subnet)
-			}
-
-			filter, err = s.nodeFilter(topicFormat, defectiveSubnets)
-			if err != nil {
-				return nil, errors.Wrap(err, "node filter")
-			}
+		updateDefectiveSubnets(nodeSubnets, defectiveSubnets)
+		filter, err = s.nodeFilter(topicFormat, defectiveSubnets)
+		if err != nil {
+			return nil, errors.Wrap(err, "node filter")
 		}
 	}
 

beacon-chain/p2p/subnets_test.go

@@ -10,14 +10,19 @@ import (
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/cache"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
 	testDB "github.com/OffchainLabs/prysm/v6/beacon-chain/db/testing"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/peers"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/peers/scorers"
+	testp2p "github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/testing"
 	"github.com/OffchainLabs/prysm/v6/cmd/beacon-chain/flags"
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	ecdsaprysm "github.com/OffchainLabs/prysm/v6/crypto/ecdsa"
+	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
 	"github.com/OffchainLabs/prysm/v6/testing/assert"
 	"github.com/OffchainLabs/prysm/v6/testing/require"
 	"github.com/ethereum/go-ethereum/p2p/enode"
 	"github.com/ethereum/go-ethereum/p2p/enr"
 	"github.com/libp2p/go-libp2p/core/crypto"
+	"github.com/libp2p/go-libp2p/core/network"
 	"github.com/prysmaticlabs/go-bitfield"
 )
 
@@ -541,3 +546,552 @@ func TestInitializePersistentSubnets(t *testing.T) {
 	assert.Equal(t, 2, len(subs))
 	assert.Equal(t, true, expTime.After(time.Now()))
 }
+
+func TestFindPeersWithSubnets_NodeDeduplication(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	cache.SubnetIDs.EmptyAllCaches()
+	defer cache.SubnetIDs.EmptyAllCaches()
+
+	ctx := context.Background()
+	db := testDB.SetupDB(t)
+
+	localNode1 := createTestNodeWithID(t, "node1")
+	localNode2 := createTestNodeWithID(t, "node2")
+	localNode3 := createTestNodeWithID(t, "node3")
+
+	// Create different sequence versions of node1 with subnet 1
+	setNodeSubnets(localNode1, []uint64{1})
+	setNodeSeq(localNode1, 1)
+	node1_seq1_subnet1 := localNode1.Node()
+	setNodeSeq(localNode1, 2)
+	node1_seq2_subnet1 := localNode1.Node() // Same ID, higher seq
+	setNodeSeq(localNode1, 3)
+	node1_seq3_subnet1 := localNode1.Node() // Same ID, even higher seq
+
+	// Node2 with different sequences and subnets
+	setNodeSubnets(localNode2, []uint64{1})
+	node2_seq1_subnet1 := localNode2.Node()
+	setNodeSubnets(localNode2, []uint64{2}) // Different subnet
+	setNodeSeq(localNode2, 2)
+	node2_seq2_subnet2 := localNode2.Node()
+
+	// Node3 with multiple subnets
+	setNodeSubnets(localNode3, []uint64{1, 2})
+	node3_seq1_subnet1_2 := localNode3.Node()
+
+	tests := []struct {
+		name             string
+		nodes            []*enode.Node
+		defectiveSubnets map[uint64]int
+		expectedCount    int
+		description      string
+		eval             func(t *testing.T, result []*enode.Node) // Custom validation function
+	}{
+		{
+			name: "No duplicates - unique nodes with same subnet",
+			nodes: []*enode.Node{
+				node2_seq1_subnet1,
+				node3_seq1_subnet1_2,
+			},
+			defectiveSubnets: map[uint64]int{1: 2},
+			expectedCount:    2,
+			description:      "Should return all unique nodes subscribed to subnet",
+			eval:             nil, // No special validation needed
+		},
+		{
+			name: "Duplicate with lower seq first - should replace",
+			nodes: []*enode.Node{
+				node1_seq1_subnet1,
+				node1_seq2_subnet1, // Higher seq, should replace
+				node2_seq1_subnet1, // Different node to ensure we process enough nodes
+			},
+			defectiveSubnets: map[uint64]int{1: 2}, // Need 2 peers for subnet 1
+			expectedCount:    2,
+			description:      "Should replace with higher seq node for same subnet",
+			eval: func(t *testing.T, result []*enode.Node) {
+				found := false
+				for _, node := range result {
+					if node.ID() == node1_seq2_subnet1.ID() && node.Seq() == node1_seq2_subnet1.Seq() {
+						found = true
+						break
+					}
+				}
+				require.Equal(t, true, found, "Should have node with higher seq")
+			},
+		},
+		{
+			name: "Duplicate with higher seq first - should keep existing",
+			nodes: []*enode.Node{
+				node1_seq3_subnet1, // Higher seq
+				node1_seq2_subnet1, // Lower seq, should be skipped (continue branch)
+				node1_seq1_subnet1, // Even lower seq, should also be skipped (continue branch)
+				node2_seq1_subnet1, // Different node
+			},
+			defectiveSubnets: map[uint64]int{1: 2},
+			expectedCount:    2,
+			description:      "Should keep existing node with higher seq and skip lower seq duplicates",
+			eval: func(t *testing.T, result []*enode.Node) {
+				found := false
+				for _, node := range result {
+					if node.ID() == node1_seq3_subnet1.ID() && node.Seq() == node1_seq3_subnet1.Seq() {
+						found = true
+						break
+					}
+				}
+				require.Equal(t, true, found, "Should have node with highest seq")
+			},
+		},
+		{
+			name: "Multiple updates for same node",
+			nodes: []*enode.Node{
+				node1_seq1_subnet1,
+				node1_seq2_subnet1, // Should replace seq1
+				node1_seq3_subnet1, // Should replace seq2
+				node2_seq1_subnet1, // Different node
+			},
+			defectiveSubnets: map[uint64]int{1: 2},
+			expectedCount:    2,
+			description:      "Should keep updating to highest seq",
+			eval: func(t *testing.T, result []*enode.Node) {
+				found := false
+				for _, node := range result {
+					if node.ID() == node1_seq3_subnet1.ID() && node.Seq() == node1_seq3_subnet1.Seq() {
+						found = true
+						break
+					}
+				}
+				require.Equal(t, true, found, "Should have node with highest seq")
+			},
+		},
+		{
+			name: "Duplicate with equal seq in subnets - should skip",
+			nodes: []*enode.Node{
+				node1_seq2_subnet1, // First occurrence
+				node1_seq2_subnet1, // Same exact node instance, should be skipped (continue branch)
+				node2_seq1_subnet1, // Different node
+			},
+			defectiveSubnets: map[uint64]int{1: 2},
+			expectedCount:    2,
+			description:      "Should skip duplicate with equal sequence number in subnet search",
+			eval: func(t *testing.T, result []*enode.Node) {
+				foundNode1 := false
+				foundNode2 := false
+				node1Count := 0
+				for _, node := range result {
+					if node.ID() == node1_seq2_subnet1.ID() {
+						require.Equal(t, node1_seq2_subnet1.Seq(), node.Seq(), "Node1 should have expected seq")
+						foundNode1 = true
+						node1Count++
+					}
+					if node.ID() == node2_seq1_subnet1.ID() {
+						foundNode2 = true
+					}
+				}
+				require.Equal(t, true, foundNode1, "Should have node1")
+				require.Equal(t, true, foundNode2, "Should have node2")
+				require.Equal(t, 1, node1Count, "Should have exactly one instance of node1")
+			},
+		},
+		{
+			name: "Mix with different subnets",
+			nodes: []*enode.Node{
+				node2_seq1_subnet1,
+				node2_seq2_subnet2, // Higher seq but different subnet
+				node3_seq1_subnet1_2,
+			},
+			defectiveSubnets: map[uint64]int{1: 2, 2: 1},
+			expectedCount:    2, // node2 (latest) and node3
+			description:      "Should handle nodes with different subnet subscriptions",
+			eval:             nil, // Basic count validation is sufficient
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			gFlags := new(flags.GlobalFlags)
+			gFlags.MinimumPeersPerSubnet = 1
+			flags.Init(gFlags)
+			defer flags.Init(new(flags.GlobalFlags))
+
+			fakePeer := testp2p.NewTestP2P(t)
+
+			s := &Service{
+				cfg: &Config{
+					MaxPeers: 30,
+					DB:       db,
+				},
+				genesisTime:           time.Now(),
+				genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
+				peers: peers.NewStatus(ctx, &peers.StatusConfig{
+					PeerLimit:    30,
+					ScorerParams: &scorers.Config{},
+				}),
+				host: fakePeer.BHost,
+			}
+
+			localNode := createTestNodeRandom(t)
+
+			mockIter := testp2p.NewMockIterator(tt.nodes)
+			s.dv5Listener = testp2p.NewMockListener(localNode, mockIter)
+
+			digest, err := s.currentForkDigest()
+			require.NoError(t, err)
+
+			ctxWithTimeout, cancel := context.WithTimeout(ctx, 100*time.Millisecond)
+			defer cancel()
+
+			result, err := s.findPeersWithSubnets(
+				ctxWithTimeout,
+				AttestationSubnetTopicFormat,
+				digest,
+				1,
+				tt.defectiveSubnets,
+			)
+
+			require.NoError(t, err, tt.description)
+			require.Equal(t, tt.expectedCount, len(result), tt.description)
+
+			if tt.eval != nil {
+				tt.eval(t, result)
+			}
+		})
+	}
+}
+
+func TestFindPeersWithSubnets_FilterPeerRemoval(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	cache.SubnetIDs.EmptyAllCaches()
+	defer cache.SubnetIDs.EmptyAllCaches()
+
+	ctx := context.Background()
+	db := testDB.SetupDB(t)
+
+	localNode1 := createTestNodeWithID(t, "node1")
+	localNode2 := createTestNodeWithID(t, "node2")
+	localNode3 := createTestNodeWithID(t, "node3")
+
+	// Create versions of node1 with subnet 1
+	setNodeSubnets(localNode1, []uint64{1})
+	setNodeSeq(localNode1, 1)
+	node1_seq1_valid_subnet1 := localNode1.Node()
+
+	// Create bad version (higher seq)
+	setNodeSeq(localNode1, 2)
+	node1_seq2_bad_subnet1 := localNode1.Node()
+
+	// Create another valid version
+	setNodeSeq(localNode1, 3)
+	node1_seq3_valid_subnet1 := localNode1.Node()
+
+	// Node2 with subnet 1
+	setNodeSubnets(localNode2, []uint64{1})
+	node2_seq1_valid_subnet1 := localNode2.Node()
+
+	// Node3 with subnet 1 and 2
+	setNodeSubnets(localNode3, []uint64{1, 2})
+	node3_seq1_valid_subnet1_2 := localNode3.Node()
+
+	tests := []struct {
+		name             string
+		nodes            []*enode.Node
+		defectiveSubnets map[uint64]int
+		expectedCount    int
+		description      string
+		eval             func(t *testing.T, result []*enode.Node)
+	}{
+		{
+			name: "Valid node in subnet followed by bad version - should remove",
+			nodes: []*enode.Node{
+				node1_seq1_valid_subnet1, // First add valid node with subnet 1
+				node1_seq2_bad_subnet1,   // Invalid version with higher seq - should delete
+				node2_seq1_valid_subnet1, // Different valid node with subnet 1
+			},
+			defectiveSubnets: map[uint64]int{1: 2}, // Need 2 peers for subnet 1
+			expectedCount:    1,                    // Only node2 should remain
+			description:      "Should remove node from map when bad version arrives, even if it has required subnet",
+			eval: func(t *testing.T, result []*enode.Node) {
+				foundNode1 := false
+				foundNode2 := false
+				for _, node := range result {
+					if node.ID() == node1_seq1_valid_subnet1.ID() {
+						foundNode1 = true
+					}
+					if node.ID() == node2_seq1_valid_subnet1.ID() {
+						foundNode2 = true
+					}
+				}
+				require.Equal(t, false, foundNode1, "Node1 should have been removed despite having subnet")
+				require.Equal(t, true, foundNode2, "Node2 should be present")
+			},
+		},
+		{
+			name: "Bad node with subnet stays bad even with higher seq",
+			nodes: []*enode.Node{
+				node1_seq2_bad_subnet1,   // First bad node - not added
+				node1_seq3_valid_subnet1, // Higher seq but same bad peer ID
+				node2_seq1_valid_subnet1, // Different valid node
+			},
+			defectiveSubnets: map[uint64]int{1: 2},
+			expectedCount:    1, // Only node2 (node1 remains bad)
+			description:      "Bad peer with subnet remains bad even with higher seq",
+			eval: func(t *testing.T, result []*enode.Node) {
+				foundNode1 := false
+				foundNode2 := false
+				for _, node := range result {
+					if node.ID() == node1_seq3_valid_subnet1.ID() {
+						foundNode1 = true
+					}
+					if node.ID() == node2_seq1_valid_subnet1.ID() {
+						foundNode2 = true
+					}
+				}
+				require.Equal(t, false, foundNode1, "Node1 should remain bad despite having subnet")
+				require.Equal(t, true, foundNode2, "Node2 should be present")
+			},
+		},
+		{
+			name: "Mixed valid and bad nodes with subnets",
+			nodes: []*enode.Node{
+				node1_seq1_valid_subnet1,   // Add valid node1 with subnet
+				node2_seq1_valid_subnet1,   // Add valid node2 with subnet
+				node1_seq2_bad_subnet1,     // Invalid update for node1 - should remove
+				node3_seq1_valid_subnet1_2, // Add valid node3 with multiple subnets
+			},
+			defectiveSubnets: map[uint64]int{1: 3}, // Need 3 peers for subnet 1
+			expectedCount:    2,                    // Only node2 and node3 should remain
+			description:      "Should handle removal of nodes with subnets when they become bad",
+			eval: func(t *testing.T, result []*enode.Node) {
+				foundNode1 := false
+				foundNode2 := false
+				foundNode3 := false
+				for _, node := range result {
+					if node.ID() == node1_seq1_valid_subnet1.ID() {
+						foundNode1 = true
+					}
+					if node.ID() == node2_seq1_valid_subnet1.ID() {
+						foundNode2 = true
+					}
+					if node.ID() == node3_seq1_valid_subnet1_2.ID() {
+						foundNode3 = true
+					}
+				}
+				require.Equal(t, false, foundNode1, "Node1 should have been removed")
+				require.Equal(t, true, foundNode2, "Node2 should be present")
+				require.Equal(t, true, foundNode3, "Node3 should be present")
+			},
+		},
+		{
+			name: "Node with subnet marked bad stays bad for all sequences",
+			nodes: []*enode.Node{
+				node1_seq1_valid_subnet1, // Add valid node1 with subnet
+				node1_seq2_bad_subnet1,   // Bad update - should remove and mark bad
+				node1_seq3_valid_subnet1, // Higher seq but still same bad peer ID
+				node2_seq1_valid_subnet1, // Different valid node
+			},
+			defectiveSubnets: map[uint64]int{1: 2},
+			expectedCount:    1, // Only node2 (node1 stays bad)
+			description:      "Once marked bad, subnet peer stays bad for all sequences",
+			eval: func(t *testing.T, result []*enode.Node) {
+				foundNode1 := false
+				foundNode2 := false
+				for _, node := range result {
+					if node.ID() == node1_seq3_valid_subnet1.ID() {
+						foundNode1 = true
+					}
+					if node.ID() == node2_seq1_valid_subnet1.ID() {
+						foundNode2 = true
+					}
+				}
+				require.Equal(t, false, foundNode1, "Node1 should stay bad")
+				require.Equal(t, true, foundNode2, "Node2 should be present")
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Initialize flags for subnet operations
+			gFlags := new(flags.GlobalFlags)
+			gFlags.MinimumPeersPerSubnet = 1
+			flags.Init(gFlags)
+			defer flags.Init(new(flags.GlobalFlags))
+
+			// Create test P2P instance
+			fakePeer := testp2p.NewTestP2P(t)
+
+			// Create mock service
+			s := &Service{
+				cfg: &Config{
+					MaxPeers: 30,
+					DB:       db,
+				},
+				genesisTime:           time.Now(),
+				genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
+				peers: peers.NewStatus(ctx, &peers.StatusConfig{
+					PeerLimit:    30,
+					ScorerParams: &scorers.Config{},
+				}),
+				host: fakePeer.BHost,
+			}
+
+			// Mark specific node versions as "bad" to simulate filterPeer failures
+			for _, node := range tt.nodes {
+				if node == node1_seq2_bad_subnet1 {
+					// Get peer ID from the node to mark it as bad
+					peerData, _, _ := convertToAddrInfo(node)
+					if peerData != nil {
+						s.peers.Add(node.Record(), peerData.ID, nil, network.DirUnknown)
+						// Mark as bad peer - this will make filterPeer return false
+						s.peers.Scorers().BadResponsesScorer().Increment(peerData.ID)
+						s.peers.Scorers().BadResponsesScorer().Increment(peerData.ID)
+						s.peers.Scorers().BadResponsesScorer().Increment(peerData.ID)
+					}
+				}
+			}
+
+			localNode := createTestNodeRandom(t)
+
+			mockIter := testp2p.NewMockIterator(tt.nodes)
+			s.dv5Listener = testp2p.NewMockListener(localNode, mockIter)
+
+			digest, err := s.currentForkDigest()
+			require.NoError(t, err)
+
+			ctxWithTimeout, cancel := context.WithTimeout(ctx, 100*time.Millisecond)
+			defer cancel()
+
+			result, err := s.findPeersWithSubnets(
+				ctxWithTimeout,
+				AttestationSubnetTopicFormat,
+				digest,
+				1,
+				tt.defectiveSubnets,
+			)
+
+			require.NoError(t, err, tt.description)
+			require.Equal(t, tt.expectedCount, len(result), tt.description)
+
+			if tt.eval != nil {
+				tt.eval(t, result)
+			}
+		})
+	}
+}
+
+// callbackIterator allows us to execute callbacks at specific points during iteration
+type callbackIteratorForSubnets struct {
+	nodes     []*enode.Node
+	index     int
+	callbacks map[int]func() // map from index to callback function
+}
+
+func (c *callbackIteratorForSubnets) Next() bool {
+	// Execute callback before checking if we can continue (if one exists)
+	if callback, exists := c.callbacks[c.index]; exists {
+		callback()
+	}
+
+	return c.index < len(c.nodes)
+}
+
+func (c *callbackIteratorForSubnets) Node() *enode.Node {
+	if c.index >= len(c.nodes) {
+		return nil
+	}
+
+	node := c.nodes[c.index]
+	c.index++
+	return node
+}
+
+func (c *callbackIteratorForSubnets) Close() {
+	// Nothing to clean up for this simple implementation
+}
+
+func TestFindPeersWithSubnets_received_bad_existing_node(t *testing.T) {
+	// This test successfully triggers delete(nodeByNodeID, node.ID()) in subnets.go by:
+	// 1. Processing node1_seq1 first (passes filterPeer, gets added to map
+	// 2. Callback marks peer as bad before processing node1_seq2"
+	// 3. Processing node1_seq2 (fails filterPeer, triggers delete since ok=true
+	params.SetupTestConfigCleanup(t)
+	cache.SubnetIDs.EmptyAllCaches()
+	defer cache.SubnetIDs.EmptyAllCaches()
+
+	ctx := context.Background()
+	db := testDB.SetupDB(t)
+
+	// Create LocalNode with same ID but different sequences
+	localNode1 := createTestNodeWithID(t, "testnode")
+	setNodeSubnets(localNode1, []uint64{1})
+	node1_seq1 := localNode1.Node() // Get current node
+	currentSeq := node1_seq1.Seq()
+	setNodeSeq(localNode1, currentSeq+1) // Increment sequence by 1
+	node1_seq2 := localNode1.Node()      // This should have higher seq
+
+	// Additional node to ensure we have enough peers to process
+	localNode2 := createTestNodeWithID(t, "othernode")
+	setNodeSubnets(localNode2, []uint64{1})
+	node2 := localNode2.Node()
+
+	gFlags := new(flags.GlobalFlags)
+	gFlags.MinimumPeersPerSubnet = 1
+	flags.Init(gFlags)
+	defer flags.Init(new(flags.GlobalFlags))
+
+	fakePeer := testp2p.NewTestP2P(t)
+
+	service := &Service{
+		cfg: &Config{
+			MaxPeers: 30,
+			DB:       db,
+		},
+		genesisTime:           time.Now(),
+		genesisValidatorsRoot: bytesutil.PadTo([]byte{'A'}, 32),
+		peers: peers.NewStatus(ctx, &peers.StatusConfig{
+			PeerLimit:    30,
+			ScorerParams: &scorers.Config{},
+		}),
+		host: fakePeer.BHost,
+	}
+
+	// Create iterator with callback that marks peer as bad before processing node1_seq2
+	iter := &callbackIteratorForSubnets{
+		nodes: []*enode.Node{node1_seq1, node1_seq2, node2},
+		index: 0,
+		callbacks: map[int]func(){
+			1: func() { // Before processing node1_seq2 (index 1)
+				// Mark peer as bad before processing node1_seq2
+				peerData, _, _ := convertToAddrInfo(node1_seq2)
+				if peerData != nil {
+					service.peers.Add(node1_seq2.Record(), peerData.ID, nil, network.DirUnknown)
+					// Mark as bad peer - need enough increments to exceed threshold (6)
+					for i := 0; i < 10; i++ {
+						service.peers.Scorers().BadResponsesScorer().Increment(peerData.ID)
+					}
+				}
+			},
+		},
+	}
+
+	localNode := createTestNodeRandom(t)
+	service.dv5Listener = testp2p.NewMockListener(localNode, iter)
+
+	digest, err := service.currentForkDigest()
+	require.NoError(t, err)
+
+	// Run findPeersWithSubnets - node1_seq1 gets processed first, then callback marks peer bad, then node1_seq2 fails
+	ctxWithTimeout, cancel := context.WithTimeout(ctx, 1*time.Second)
+	defer cancel()
+
+	result, err := service.findPeersWithSubnets(
+		ctxWithTimeout,
+		AttestationSubnetTopicFormat,
+		digest,
+		1,
+		map[uint64]int{1: 2}, // Need 2 peers for subnet 1
+	)
+
+	require.NoError(t, err)
+	require.Equal(t, 1, len(result))
+	require.Equal(t, localNode2.Node().ID(), result[0].ID()) // only node2 should remain
+}

beacon-chain/p2p/testing/BUILD.bazel

@@ -7,6 +7,7 @@ go_library(
         "fuzz_p2p.go",
         "mock_broadcaster.go",
         "mock_host.go",
+        "mock_listener.go",
         "mock_metadataprovider.go",
         "mock_peermanager.go",
         "mock_peersprovider.go",

beacon-chain/p2p/testing/mock_listener.go

@@ -0,0 +1,128 @@
+package testing
+
+import (
+	"github.com/ethereum/go-ethereum/p2p/enode"
+)
+
+// MockListener is a mock implementation of the Listener and ListenerRebooter interfaces
+// that can be used in tests. It provides configurable behavior for all methods.
+type MockListener struct {
+	LocalNodeFunc   func() *enode.LocalNode
+	SelfFunc        func() *enode.Node
+	RandomNodesFunc func() enode.Iterator
+	LookupFunc      func(enode.ID) []*enode.Node
+	ResolveFunc     func(*enode.Node) *enode.Node
+	PingFunc        func(*enode.Node) error
+	RequestENRFunc  func(*enode.Node) (*enode.Node, error)
+	RebootFunc      func() error
+	CloseFunc       func()
+
+	// Default implementations
+	localNode *enode.LocalNode
+	iterator  enode.Iterator
+}
+
+// NewMockListener creates a new MockListener with default implementations
+func NewMockListener(localNode *enode.LocalNode, iterator enode.Iterator) *MockListener {
+	return &MockListener{
+		localNode: localNode,
+		iterator:  iterator,
+	}
+}
+
+func (m *MockListener) LocalNode() *enode.LocalNode {
+	if m.LocalNodeFunc != nil {
+		return m.LocalNodeFunc()
+	}
+	return m.localNode
+}
+
+func (m *MockListener) Self() *enode.Node {
+	if m.SelfFunc != nil {
+		return m.SelfFunc()
+	}
+	if m.localNode != nil {
+		return m.localNode.Node()
+	}
+	return nil
+}
+
+func (m *MockListener) RandomNodes() enode.Iterator {
+	if m.RandomNodesFunc != nil {
+		return m.RandomNodesFunc()
+	}
+	return m.iterator
+}
+
+func (m *MockListener) Lookup(id enode.ID) []*enode.Node {
+	if m.LookupFunc != nil {
+		return m.LookupFunc(id)
+	}
+	return nil
+}
+
+func (m *MockListener) Resolve(node *enode.Node) *enode.Node {
+	if m.ResolveFunc != nil {
+		return m.ResolveFunc(node)
+	}
+	return nil
+}
+
+func (m *MockListener) Ping(node *enode.Node) error {
+	if m.PingFunc != nil {
+		return m.PingFunc(node)
+	}
+	return nil
+}
+
+func (m *MockListener) RequestENR(node *enode.Node) (*enode.Node, error) {
+	if m.RequestENRFunc != nil {
+		return m.RequestENRFunc(node)
+	}
+	return nil, nil
+}
+
+func (m *MockListener) RebootListener() error {
+	if m.RebootFunc != nil {
+		return m.RebootFunc()
+	}
+	return nil
+}
+
+func (m *MockListener) Close() {
+	if m.CloseFunc != nil {
+		m.CloseFunc()
+	}
+}
+
+// MockIterator is a mock implementation of enode.Iterator for testing
+type MockIterator struct {
+	Nodes    []*enode.Node
+	Position int
+	Closed   bool
+}
+
+func NewMockIterator(nodes []*enode.Node) *MockIterator {
+	return &MockIterator{
+		Nodes: nodes,
+	}
+}
+
+func (m *MockIterator) Next() bool {
+	if m.Closed || m.Position >= len(m.Nodes) {
+		return false
+	}
+	m.Position++
+	return true
+}
+
+func (m *MockIterator) Node() *enode.Node {
+	if m.Position == 0 || m.Position > len(m.Nodes) {
+		return nil
+	}
+	return m.Nodes[m.Position-1]
+}
+
+func (m *MockIterator) Close() {
+	m.Closed = true
+}

beacon-chain/p2p/testing/p2p.go

@@ -50,6 +50,7 @@ const (
 
 // TestP2P represents a p2p implementation that can be used for testing.
 type TestP2P struct {
+	mu                    sync.Mutex
 	t                     *testing.T
 	BHost                 host.Host
 	EnodeID               enode.ID
@@ -63,6 +64,7 @@ type TestP2P struct {
 	custodyInfoMut        sync.RWMutex // protects custodyGroupCount and earliestAvailableSlot
 	earliestAvailableSlot primitives.Slot
 	custodyGroupCount     uint64
+	enr                   *enr.Record
 }
 
 // NewTestP2P initializes a new p2p test service.
@@ -103,6 +105,7 @@ func NewTestP2P(t *testing.T, userOptions ...config.Option) *TestP2P {
 		pubsub:       ps,
 		joinedTopics: map[string]*pubsub.Topic{},
 		peers:        peerStatuses,
+		enr:          new(enr.Record),
 	}
 }
 
@@ -241,6 +244,8 @@ func (p *TestP2P) SetStreamHandler(topic string, handler network.StreamHandler)
 
 // JoinTopic will join PubSub topic, if not already joined.
 func (p *TestP2P) JoinTopic(topic string, opts ...pubsub.TopicOpt) (*pubsub.Topic, error) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
 	if _, ok := p.joinedTopics[topic]; !ok {
 		joinedTopic, err := p.pubsub.Join(topic, opts...)
 		if err != nil {
@@ -310,8 +315,8 @@ func (p *TestP2P) Host() host.Host {
 }
 
 // ENR returns the enr of the local peer.
-func (*TestP2P) ENR() *enr.Record {
-	return new(enr.Record)
+func (p *TestP2P) ENR() *enr.Record {
+	return p.enr
 }
 
 // NodeID returns the node id of the local peer.

beacon-chain/rpc/eth/beacon/BUILD.bazel

@@ -18,6 +18,7 @@ go_library(
         "//api/server:go_default_library",
         "//api/server/structs:go_default_library",
         "//beacon-chain/blockchain:go_default_library",
+        "//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",
@@ -60,7 +61,6 @@ go_library(
         "//runtime/version:go_default_library",
         "//time/slots:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
-        "@com_github_ethereum_go_ethereum//crypto/kzg4844:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_prometheus_client_golang//prometheus:go_default_library",
         "@com_github_prometheus_client_golang//prometheus/promauto:go_default_library",
@@ -84,6 +84,7 @@ go_test(
         "//api:go_default_library",
         "//api/server:go_default_library",
         "//api/server/structs:go_default_library",
+        "//beacon-chain/blockchain/kzg:go_default_library",
         "//beacon-chain/blockchain/testing:go_default_library",
         "//beacon-chain/cache/depositsnapshot:go_default_library",
         "//beacon-chain/core/signing:go_default_library",
@@ -124,7 +125,6 @@ go_test(
         "//testing/require:go_default_library",
         "//testing/util:go_default_library",
         "//time/slots:go_default_library",
-        "@com_github_crate_crypto_go_kzg_4844//:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_prysmaticlabs_fastssz//:go_default_library",

beacon-chain/rpc/eth/beacon/handlers.go

@@ -13,6 +13,7 @@ import (
 
 	"github.com/OffchainLabs/prysm/v6/api"
 	"github.com/OffchainLabs/prysm/v6/api/server/structs"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/kzg"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/cache/depositsnapshot"
 	corehelpers "github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/transition"
@@ -32,7 +33,6 @@ import (
 	"github.com/OffchainLabs/prysm/v6/runtime/version"
 	"github.com/OffchainLabs/prysm/v6/time/slots"
 	"github.com/ethereum/go-ethereum/common/hexutil"
-	"github.com/ethereum/go-ethereum/crypto/kzg4844"
 	"github.com/pkg/errors"
 	ssz "github.com/prysmaticlabs/fastssz"
 	"github.com/sirupsen/logrus"
@@ -334,26 +334,26 @@ func (s *Server) GetBlockAttestationsV2(w http.ResponseWriter, r *http.Request)
 	consensusAtts := blk.Block().Body().Attestations()
 
 	v := blk.Block().Version()
-	var attStructs []interface{}
+	attStructs := make([]interface{}, len(consensusAtts))
 	if v >= version.Electra {
-		for _, att := range consensusAtts {
+		for index, att := range consensusAtts {
 			a, ok := att.(*eth.AttestationElectra)
 			if !ok {
 				httputil.HandleError(w, fmt.Sprintf("unable to convert consensus attestations electra of type %T", att), http.StatusInternalServerError)
 				return
 			}
 			attStruct := structs.AttElectraFromConsensus(a)
-			attStructs = append(attStructs, attStruct)
+			attStructs[index] = attStruct
 		}
 	} else {
-		for _, att := range consensusAtts {
+		for index, att := range consensusAtts {
 			a, ok := att.(*eth.Attestation)
 			if !ok {
 				httputil.HandleError(w, fmt.Sprintf("unable to convert consensus attestation of type %T", att), http.StatusInternalServerError)
 				return
 			}
 			attStruct := structs.AttFromConsensus(a)
-			attStructs = append(attStructs, attStruct)
+			attStructs[index] = attStruct
 		}
 	}
 
@@ -942,14 +942,13 @@ func decodePhase0JSON(body []byte) (*eth.GenericSignedBeaconBlock, error) {
 // broadcastSidecarsIfSupported broadcasts blob sidecars when an equivocated block occurs.
 func broadcastSidecarsIfSupported(ctx context.Context, s *Server, b interfaces.SignedBeaconBlock, gb *eth.GenericSignedBeaconBlock, versionHeader string) error {
 	switch versionHeader {
-	case version.String(version.Fulu):
-		return s.broadcastSeenBlockSidecars(ctx, b, gb.GetFulu().Blobs, gb.GetFulu().KzgProofs)
 	case version.String(version.Electra):
 		return s.broadcastSeenBlockSidecars(ctx, b, gb.GetElectra().Blobs, gb.GetElectra().KzgProofs)
 	case version.String(version.Deneb):
 		return s.broadcastSeenBlockSidecars(ctx, b, gb.GetDeneb().Blobs, gb.GetDeneb().KzgProofs)
 	default:
 		// other forks before Deneb do not support blob sidecars
+		// forks after fulu do not support blob sidecars, instead support data columns, no need to rebroadcast
 		return nil
 	}
 }
@@ -1053,7 +1052,7 @@ func (s *Server) validateConsensus(ctx context.Context, b *eth.GenericSignedBeac
 		return nil
 	}
 
-	if err := s.validateBlobSidecars(blk, blobs, proofs); err != nil {
+	if err := s.validateBlobs(blk, blobs, proofs); err != nil {
 		return err
 	}
 
@@ -1067,23 +1066,41 @@ func (s *Server) validateEquivocation(blk interfaces.ReadOnlyBeaconBlock) error
 	return nil
 }
 
-func (s *Server) validateBlobSidecars(blk interfaces.SignedBeaconBlock, blobs [][]byte, proofs [][]byte) error {
+func (s *Server) validateBlobs(blk interfaces.SignedBeaconBlock, blobs [][]byte, proofs [][]byte) error {
 	if blk.Version() < version.Deneb {
 		return nil
 	}
-	kzgs, err := blk.Block().Body().BlobKzgCommitments()
+	numberOfColumns := params.BeaconConfig().NumberOfColumns
+	commitments, err := blk.Block().Body().BlobKzgCommitments()
 	if err != nil {
 		return errors.Wrap(err, "could not get blob kzg commitments")
 	}
-	if len(blobs) != len(proofs) || len(blobs) != len(kzgs) {
-		return errors.New("number of blobs, proofs, and commitments do not match")
+	maxBlobsPerBlock := params.BeaconConfig().MaxBlobsPerBlock(blk.Block().Slot())
+	if len(blobs) > maxBlobsPerBlock {
+		return fmt.Errorf("number of blobs over max, %d > %d", len(blobs), maxBlobsPerBlock)
 	}
-	for i, blob := range blobs {
-		b := kzg4844.Blob(blob)
-		if err := kzg4844.VerifyBlobProof(&b, kzg4844.Commitment(kzgs[i]), kzg4844.Proof(proofs[i])); err != nil {
-			return errors.Wrap(err, "could not verify blob proof")
+	if blk.Version() >= version.Fulu {
+		// For Fulu blocks, proofs are cell proofs (blobs * numberOfColumns)
+		expectedProofsCount := uint64(len(blobs)) * numberOfColumns
+		if uint64(len(proofs)) != expectedProofsCount || len(blobs) != len(commitments) {
+			return fmt.Errorf("number of blobs (%d), cell proofs (%d), and commitments (%d) do not match (expected %d cell proofs)", len(blobs), len(proofs), len(commitments), expectedProofsCount)
+		}
+		// For Fulu blocks, proofs are cell proofs from execution client's BlobsBundleV2
+		// Verify cell proofs directly without reconstructing data column sidecars
+		if err := kzg.VerifyCellKZGProofBatchFromBlobData(blobs, commitments, proofs, numberOfColumns); err != nil {
+			return errors.Wrap(err, "could not verify cell proofs")
+		}
+	} else {
+		// For pre-Fulu blocks, proofs are blob proofs (1:1 with blobs)
+		if len(blobs) != len(proofs) || len(blobs) != len(commitments) {
+			return errors.Errorf("number of blobs (%d), proofs (%d), and commitments (%d) do not match", len(blobs), len(proofs), len(commitments))
+		}
+		// Use batch verification for better performance
+		if err := kzg.VerifyBlobKZGProofBatch(blobs, commitments, proofs); err != nil {
+			return errors.Wrap(err, "could not verify blob proofs")
 		}
 	}
+
 	return nil
 }
 
@@ -1627,6 +1644,8 @@ func (s *Server) broadcastSeenBlockSidecars(
 	if err != nil {
 		return err
 	}
+
+	// Broadcast blob sidecars with forkchoice checking
 	for _, sc := range scs {
 		r, err := sc.SignedBlockHeader.Header.HashTreeRoot()
 		if err != nil {

beacon-chain/rpc/eth/beacon/handlers_equivocation_test.go

@@ -17,19 +17,19 @@ func TestBlocks_NewSignedBeaconBlock_EquivocationFix(t *testing.T) {
 	var block structs.SignedBeaconBlock
 	err := json.Unmarshal([]byte(rpctesting.Phase0Block), &block)
 	require.NoError(t, err)
-	
+
 	// Convert to generic format
 	genericBlock, err := block.ToGeneric()
 	require.NoError(t, err)
-	
+
 	// Test the FIX: pass genericBlock.Block instead of genericBlock
 	// This is what our fix changed in handlers.go line 704 and 858
 	_, err = blocks.NewSignedBeaconBlock(genericBlock.Block)
 	require.NoError(t, err, "NewSignedBeaconBlock should work with genericBlock.Block")
-	
+
 	// Test the BROKEN version: pass genericBlock directly (this should fail)
 	_, err = blocks.NewSignedBeaconBlock(genericBlock)
 	if err == nil {
 		t.Errorf("NewSignedBeaconBlock should fail with whole genericBlock but succeeded")
 	}
-}
+}

beacon-chain/rpc/eth/beacon/handlers_test.go

@@ -14,6 +14,7 @@ import (
 
 	"github.com/OffchainLabs/prysm/v6/api"
 	"github.com/OffchainLabs/prysm/v6/api/server/structs"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/kzg"
 	chainMock "github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/testing"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/cache/depositsnapshot"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/transition"
@@ -40,7 +41,6 @@ import (
 	"github.com/OffchainLabs/prysm/v6/testing/require"
 	"github.com/OffchainLabs/prysm/v6/testing/util"
 	"github.com/OffchainLabs/prysm/v6/time/slots"
-	GoKZG "github.com/crate-crypto/go-kzg-4844"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/pkg/errors"
 	ssz "github.com/prysmaticlabs/fastssz"
@@ -910,6 +910,100 @@ func TestGetBlockAttestations(t *testing.T) {
 			})
 		})
 	})
+
+	t.Run("empty-attestations", func(t *testing.T) {
+		t.Run("v1", func(t *testing.T) {
+			b := util.NewBeaconBlock()
+			b.Block.Body.Attestations = []*eth.Attestation{} // Explicitly set empty attestations
+			sb, err := blocks.NewSignedBeaconBlock(b)
+			require.NoError(t, err)
+
+			mockChainService := &chainMock.ChainService{
+				FinalizedRoots: map[[32]byte]bool{},
+			}
+
+			s := &Server{
+				OptimisticModeFetcher: mockChainService,
+				FinalizationFetcher:   mockChainService,
+				Blocker:               &testutil.MockBlocker{BlockToReturn: sb},
+			}
+
+			request := httptest.NewRequest(http.MethodGet, "http://foo.example/eth/v1/beacon/blocks/{block_id}/attestations", nil)
+			request.SetPathValue("block_id", "head")
+			writer := httptest.NewRecorder()
+			writer.Body = &bytes.Buffer{}
+
+			s.GetBlockAttestations(writer, request)
+			require.Equal(t, http.StatusOK, writer.Code)
+			resp := &structs.GetBlockAttestationsResponse{}
+			require.NoError(t, json.Unmarshal(writer.Body.Bytes(), resp))
+
+			// Ensure data is empty array, not null
+			require.NotNil(t, resp.Data)
+			assert.Equal(t, 0, len(resp.Data))
+		})
+
+		t.Run("v2-pre-electra", func(t *testing.T) {
+			b := util.NewBeaconBlock()
+			b.Block.Body.Attestations = []*eth.Attestation{} // Explicitly set empty attestations
+			sb, err := blocks.NewSignedBeaconBlock(b)
+			require.NoError(t, err)
+			mockChainService := &chainMock.ChainService{
+				FinalizedRoots: map[[32]byte]bool{},
+			}
+
+			s := &Server{
+				OptimisticModeFetcher: mockChainService,
+				FinalizationFetcher:   mockChainService,
+				Blocker:               &testutil.MockBlocker{BlockToReturn: sb},
+			}
+
+			request := httptest.NewRequest(http.MethodGet, "http://foo.example/eth/v2/beacon/blocks/{block_id}/attestations", nil)
+			request.SetPathValue("block_id", "head")
+			writer := httptest.NewRecorder()
+			writer.Body = &bytes.Buffer{}
+
+			s.GetBlockAttestationsV2(writer, request)
+			require.Equal(t, http.StatusOK, writer.Code)
+			resp := &structs.GetBlockAttestationsV2Response{}
+			require.NoError(t, json.Unmarshal(writer.Body.Bytes(), resp))
+			// Ensure data is "[]", not null
+			require.NotNil(t, resp.Data)
+			assert.Equal(t, string(json.RawMessage("[]")), string(resp.Data))
+		})
+
+		t.Run("v2-electra", func(t *testing.T) {
+			eb := util.NewBeaconBlockFulu()
+			eb.Block.Body.Attestations = []*eth.AttestationElectra{} // Explicitly set empty attestations
+			esb, err := blocks.NewSignedBeaconBlock(eb)
+			require.NoError(t, err)
+
+			mockChainService := &chainMock.ChainService{
+				FinalizedRoots: map[[32]byte]bool{},
+			}
+
+			s := &Server{
+				OptimisticModeFetcher: mockChainService,
+				FinalizationFetcher:   mockChainService,
+				Blocker:               &testutil.MockBlocker{BlockToReturn: esb},
+			}
+
+			request := httptest.NewRequest(http.MethodGet, "http://foo.example/eth/v2/beacon/blocks/{block_id}/attestations", nil)
+			request.SetPathValue("block_id", "head")
+			writer := httptest.NewRecorder()
+			writer.Body = &bytes.Buffer{}
+
+			s.GetBlockAttestationsV2(writer, request)
+			require.Equal(t, http.StatusOK, writer.Code)
+			resp := &structs.GetBlockAttestationsV2Response{}
+			require.NoError(t, json.Unmarshal(writer.Body.Bytes(), resp))
+
+			// Ensure data is "[]", not null
+			require.NotNil(t, resp.Data)
+			assert.Equal(t, string(json.RawMessage("[]")), string(resp.Data))
+			assert.Equal(t, "fulu", resp.Version)
+		})
+	})
 }
 
 func TestGetBlindedBlock(t *testing.T) {
@@ -4781,25 +4875,329 @@ func TestServer_broadcastBlobSidecars(t *testing.T) {
 	require.LogsContain(t, hook, "Broadcasted blob sidecar for already seen block")
 }
 
-func Test_validateBlobSidecars(t *testing.T) {
+func Test_validateBlobs(t *testing.T) {
+	require.NoError(t, kzg.Start())
+
 	blob := util.GetRandBlob(123)
-	commitment := GoKZG.KZGCommitment{180, 218, 156, 194, 59, 20, 10, 189, 186, 254, 132, 93, 7, 127, 104, 172, 238, 240, 237, 70, 83, 89, 1, 152, 99, 0, 165, 65, 143, 62, 20, 215, 230, 14, 205, 95, 28, 245, 54, 25, 160, 16, 178, 31, 232, 207, 38, 85}
-	proof := GoKZG.KZGProof{128, 110, 116, 170, 56, 111, 126, 87, 229, 234, 211, 42, 110, 150, 129, 206, 73, 142, 167, 243, 90, 149, 240, 240, 236, 204, 143, 182, 229, 249, 81, 27, 153, 171, 83, 70, 144, 250, 42, 1, 188, 215, 71, 235, 30, 7, 175, 86}
+	// Generate proper commitment and proof for the blob
+	var kzgBlob kzg.Blob
+	copy(kzgBlob[:], blob[:])
+	commitment, err := kzg.BlobToKZGCommitment(&kzgBlob)
+	require.NoError(t, err)
+	proof, err := kzg.ComputeBlobKZGProof(&kzgBlob, commitment)
+	require.NoError(t, err)
 	blk := util.NewBeaconBlockDeneb()
 	blk.Block.Body.BlobKzgCommitments = [][]byte{commitment[:]}
 	b, err := blocks.NewSignedBeaconBlock(blk)
 	require.NoError(t, err)
 	s := &Server{}
-	require.NoError(t, s.validateBlobSidecars(b, [][]byte{blob[:]}, [][]byte{proof[:]}))
+	require.NoError(t, s.validateBlobs(b, [][]byte{blob[:]}, [][]byte{proof[:]}))
 
-	require.ErrorContains(t, "number of blobs, proofs, and commitments do not match", s.validateBlobSidecars(b, [][]byte{blob[:]}, [][]byte{}))
+	require.ErrorContains(t, "number of blobs (1), proofs (0), and commitments (1) do not match", s.validateBlobs(b, [][]byte{blob[:]}, [][]byte{}))
 
 	sk, err := bls.RandKey()
 	require.NoError(t, err)
 	blk.Block.Body.BlobKzgCommitments = [][]byte{sk.PublicKey().Marshal()}
 	b, err = blocks.NewSignedBeaconBlock(blk)
 	require.NoError(t, err)
-	require.ErrorContains(t, "could not verify blob proof: can't verify opening proof", s.validateBlobSidecars(b, [][]byte{blob[:]}, [][]byte{proof[:]}))
+	require.ErrorContains(t, "could not verify blob proofs", s.validateBlobs(b, [][]byte{blob[:]}, [][]byte{proof[:]}))
+
+	blobs := [][]byte{}
+	commitments := [][]byte{}
+	proofs := [][]byte{}
+	for i := 0; i < 10; i++ {
+		blobs = append(blobs, blob[:])
+		commitments = append(commitments, commitment[:])
+		proofs = append(proofs, proof[:])
+	}
+	t.Run("pre-Deneb block should return early", func(t *testing.T) {
+		// Create a pre-Deneb block (e.g., Capella)
+		blk := util.NewBeaconBlockCapella()
+		b, err := blocks.NewSignedBeaconBlock(blk)
+		require.NoError(t, err)
+		s := &Server{}
+		// Should return nil for pre-Deneb blocks regardless of blobs
+		require.NoError(t, s.validateBlobs(b, [][]byte{}, [][]byte{}))
+		require.NoError(t, s.validateBlobs(b, blobs[:1], proofs[:1]))
+	})
+
+	t.Run("Deneb block with valid single blob", func(t *testing.T) {
+		blk := util.NewBeaconBlockDeneb()
+		blk.Block.Body.BlobKzgCommitments = [][]byte{commitment[:]}
+		b, err := blocks.NewSignedBeaconBlock(blk)
+		require.NoError(t, err)
+		s := &Server{}
+		require.NoError(t, s.validateBlobs(b, [][]byte{blob[:]}, [][]byte{proof[:]}))
+	})
+
+	t.Run("Deneb block with max blobs (6)", func(t *testing.T) {
+		cfg := params.BeaconConfig().Copy()
+		defer params.OverrideBeaconConfig(cfg)
+
+		testCfg := params.BeaconConfig().Copy()
+		testCfg.DenebForkEpoch = 0
+		testCfg.ElectraForkEpoch = 100
+		testCfg.DeprecatedMaxBlobsPerBlock = 6
+		params.OverrideBeaconConfig(testCfg)
+
+		blk := util.NewBeaconBlockDeneb()
+		blk.Block.Slot = 10 // Deneb slot
+		blk.Block.Body.BlobKzgCommitments = commitments[:6]
+		b, err := blocks.NewSignedBeaconBlock(blk)
+		require.NoError(t, err)
+		s := &Server{}
+		// Should pass with exactly 6 blobs
+		require.NoError(t, s.validateBlobs(b, blobs[:6], proofs[:6]))
+	})
+
+	t.Run("Deneb block exceeding max blobs", func(t *testing.T) {
+		cfg := params.BeaconConfig().Copy()
+		defer params.OverrideBeaconConfig(cfg)
+
+		testCfg := params.BeaconConfig().Copy()
+		testCfg.DenebForkEpoch = 0
+		testCfg.ElectraForkEpoch = 100
+		testCfg.DeprecatedMaxBlobsPerBlock = 6
+		params.OverrideBeaconConfig(testCfg)
+
+		blk := util.NewBeaconBlockDeneb()
+		blk.Block.Slot = 10 // Deneb slot
+		blk.Block.Body.BlobKzgCommitments = commitments[:7]
+		b, err := blocks.NewSignedBeaconBlock(blk)
+		require.NoError(t, err)
+		s := &Server{}
+		// Should fail with 7 blobs when max is 6
+		err = s.validateBlobs(b, blobs[:7], proofs[:7])
+		require.ErrorContains(t, "number of blobs over max, 7 > 6", err)
+	})
+
+	t.Run("Electra block with valid blobs", func(t *testing.T) {
+		cfg := params.BeaconConfig().Copy()
+		defer params.OverrideBeaconConfig(cfg)
+
+		// Set up Electra config with max 9 blobs
+		testCfg := params.BeaconConfig().Copy()
+		testCfg.DenebForkEpoch = 0
+		testCfg.ElectraForkEpoch = 5
+		testCfg.DeprecatedMaxBlobsPerBlock = 6
+		testCfg.DeprecatedMaxBlobsPerBlockElectra = 9
+		params.OverrideBeaconConfig(testCfg)
+
+		blk := util.NewBeaconBlockElectra()
+		blk.Block.Slot = 160 // Electra slot (epoch 5+)
+		blk.Block.Body.BlobKzgCommitments = commitments[:9]
+		b, err := blocks.NewSignedBeaconBlock(blk)
+		require.NoError(t, err)
+		s := &Server{}
+		// Should pass with 9 blobs in Electra
+		require.NoError(t, s.validateBlobs(b, blobs[:9], proofs[:9]))
+	})
+
+	t.Run("Electra block exceeding max blobs", func(t *testing.T) {
+		cfg := params.BeaconConfig().Copy()
+		defer params.OverrideBeaconConfig(cfg)
+
+		// Set up Electra config with max 9 blobs
+		testCfg := params.BeaconConfig().Copy()
+		testCfg.DenebForkEpoch = 0
+		testCfg.ElectraForkEpoch = 5
+		testCfg.DeprecatedMaxBlobsPerBlock = 6
+		testCfg.DeprecatedMaxBlobsPerBlockElectra = 9
+		params.OverrideBeaconConfig(testCfg)
+
+		blk := util.NewBeaconBlockElectra()
+		blk.Block.Slot = 160 // Electra slot
+		blk.Block.Body.BlobKzgCommitments = commitments[:10]
+		b, err := blocks.NewSignedBeaconBlock(blk)
+		require.NoError(t, err)
+		s := &Server{}
+		// Should fail with 10 blobs when max is 9
+		err = s.validateBlobs(b, blobs[:10], proofs[:10])
+		require.ErrorContains(t, "number of blobs over max, 10 > 9", err)
+	})
+
+	t.Run("Fulu block with valid cell proofs", func(t *testing.T) {
+		cfg := params.BeaconConfig().Copy()
+		defer params.OverrideBeaconConfig(cfg)
+
+		testCfg := params.BeaconConfig().Copy()
+		testCfg.DenebForkEpoch = 0
+		testCfg.ElectraForkEpoch = 5
+		testCfg.FuluForkEpoch = 10
+		testCfg.DeprecatedMaxBlobsPerBlock = 6
+		testCfg.DeprecatedMaxBlobsPerBlockElectra = 9
+		testCfg.NumberOfColumns = 128 // Standard PeerDAS configuration
+		params.OverrideBeaconConfig(testCfg)
+
+		// Create Fulu block with proper cell proofs
+		blk := util.NewBeaconBlockFulu()
+		blk.Block.Slot = 320 // Epoch 10 (Fulu fork)
+
+		// Generate valid commitments and cell proofs for testing
+		blobCount := 2
+		commitments := make([][]byte, blobCount)
+		fuluBlobs := make([][]byte, blobCount)
+		var kzgBlobs []kzg.Blob
+
+		for i := 0; i < blobCount; i++ {
+			blob := util.GetRandBlob(int64(i))
+			fuluBlobs[i] = blob[:]
+			var kzgBlob kzg.Blob
+			copy(kzgBlob[:], blob[:])
+			kzgBlobs = append(kzgBlobs, kzgBlob)
+
+			// Generate commitment
+			commitment, err := kzg.BlobToKZGCommitment(&kzgBlob)
+			require.NoError(t, err)
+			commitments[i] = commitment[:]
+		}
+
+		blk.Block.Body.BlobKzgCommitments = commitments
+		b, err := blocks.NewSignedBeaconBlock(blk)
+		require.NoError(t, err)
+
+		// Generate cell proofs for the blobs (flattened format like execution client)
+		numberOfColumns := params.BeaconConfig().NumberOfColumns
+		cellProofs := make([][]byte, uint64(blobCount)*numberOfColumns)
+		for blobIdx := 0; blobIdx < blobCount; blobIdx++ {
+			cellsAndProofs, err := kzg.ComputeCellsAndKZGProofs(&kzgBlobs[blobIdx])
+			require.NoError(t, err)
+
+			for colIdx := uint64(0); colIdx < numberOfColumns; colIdx++ {
+				cellProofIdx := uint64(blobIdx)*numberOfColumns + colIdx
+				cellProofs[cellProofIdx] = cellsAndProofs.Proofs[colIdx][:]
+			}
+		}
+
+		s := &Server{}
+		// Should use cell batch verification for Fulu blocks
+		require.NoError(t, s.validateBlobs(b, fuluBlobs, cellProofs))
+	})
+
+	t.Run("Fulu block with invalid cell proof count", func(t *testing.T) {
+		cfg := params.BeaconConfig().Copy()
+		defer params.OverrideBeaconConfig(cfg)
+
+		testCfg := params.BeaconConfig().Copy()
+		testCfg.DenebForkEpoch = 0
+		testCfg.ElectraForkEpoch = 5
+		testCfg.FuluForkEpoch = 10
+		testCfg.NumberOfColumns = 128
+		params.OverrideBeaconConfig(testCfg)
+
+		blk := util.NewBeaconBlockFulu()
+		blk.Block.Slot = 320 // Epoch 10 (Fulu fork)
+
+		// Create valid commitments but wrong number of cell proofs
+		blobCount := 2
+		commitments := make([][]byte, blobCount)
+		fuluBlobs := make([][]byte, blobCount)
+		for i := 0; i < blobCount; i++ {
+			blob := util.GetRandBlob(int64(i))
+			fuluBlobs[i] = blob[:]
+
+			var kzgBlob kzg.Blob
+			copy(kzgBlob[:], blob[:])
+			commitment, err := kzg.BlobToKZGCommitment(&kzgBlob)
+			require.NoError(t, err)
+			commitments[i] = commitment[:]
+		}
+
+		blk.Block.Body.BlobKzgCommitments = commitments
+		b, err := blocks.NewSignedBeaconBlock(blk)
+		require.NoError(t, err)
+
+		// Wrong number of cell proofs (should be blobCount * numberOfColumns)
+		wrongCellProofs := make([][]byte, 10) // Too few proofs
+
+		s := &Server{}
+		err = s.validateBlobs(b, fuluBlobs, wrongCellProofs)
+		require.ErrorContains(t, "do not match", err)
+	})
+
+	t.Run("Deneb block with invalid blob proof", func(t *testing.T) {
+		blob := util.GetRandBlob(123)
+		invalidProof := make([]byte, 48) // All zeros - invalid proof
+
+		sk, err := bls.RandKey()
+		require.NoError(t, err)
+
+		blk := util.NewBeaconBlockDeneb()
+		blk.Block.Body.BlobKzgCommitments = [][]byte{sk.PublicKey().Marshal()}
+		b, err := blocks.NewSignedBeaconBlock(blk)
+		require.NoError(t, err)
+
+		s := &Server{}
+		err = s.validateBlobs(b, [][]byte{blob[:]}, [][]byte{invalidProof})
+		require.ErrorContains(t, "could not verify blob proofs", err)
+	})
+
+	t.Run("empty blobs and proofs should pass", func(t *testing.T) {
+		blk := util.NewBeaconBlockDeneb()
+		blk.Block.Body.BlobKzgCommitments = [][]byte{}
+		b, err := blocks.NewSignedBeaconBlock(blk)
+		require.NoError(t, err)
+
+		s := &Server{}
+		require.NoError(t, s.validateBlobs(b, [][]byte{}, [][]byte{}))
+	})
+
+	t.Run("BlobSchedule with progressive increases (BPO)", func(t *testing.T) {
+		cfg := params.BeaconConfig().Copy()
+		defer params.OverrideBeaconConfig(cfg)
+
+		// Set up config with BlobSchedule (BPO - Blob Production Optimization)
+		testCfg := params.BeaconConfig().Copy()
+		testCfg.DenebForkEpoch = 0
+		testCfg.ElectraForkEpoch = 100
+		testCfg.FuluForkEpoch = 200
+		testCfg.DeprecatedMaxBlobsPerBlock = 6
+		testCfg.DeprecatedMaxBlobsPerBlockElectra = 9
+		// Define blob schedule with progressive increases
+		testCfg.BlobSchedule = []params.BlobScheduleEntry{
+			{Epoch: 0, MaxBlobsPerBlock: 3},  // Start with 3 blobs
+			{Epoch: 10, MaxBlobsPerBlock: 5}, // Increase to 5 at epoch 10
+			{Epoch: 20, MaxBlobsPerBlock: 7}, // Increase to 7 at epoch 20
+			{Epoch: 30, MaxBlobsPerBlock: 9}, // Increase to 9 at epoch 30
+		}
+		params.OverrideBeaconConfig(testCfg)
+
+		s := &Server{}
+
+		// Test epoch 0-9: max 3 blobs
+		t.Run("epoch 0-9: max 3 blobs", func(t *testing.T) {
+			blk := util.NewBeaconBlockDeneb()
+			blk.Block.Slot = 5 // Epoch 0
+			blk.Block.Body.BlobKzgCommitments = commitments[:3]
+			b, err := blocks.NewSignedBeaconBlock(blk)
+			require.NoError(t, err)
+			require.NoError(t, s.validateBlobs(b, blobs[:3], proofs[:3]))
+
+			// Should fail with 4 blobs
+			blk.Block.Body.BlobKzgCommitments = commitments[:4]
+			b, err = blocks.NewSignedBeaconBlock(blk)
+			require.NoError(t, err)
+			err = s.validateBlobs(b, blobs[:4], proofs[:4])
+			require.ErrorContains(t, "number of blobs over max, 4 > 3", err)
+		})
+
+		// Test epoch 30+: max 9 blobs
+		t.Run("epoch 30+: max 9 blobs", func(t *testing.T) {
+			blk := util.NewBeaconBlockDeneb()
+			blk.Block.Slot = 960 // Epoch 30
+			blk.Block.Body.BlobKzgCommitments = commitments[:9]
+			b, err := blocks.NewSignedBeaconBlock(blk)
+			require.NoError(t, err)
+			require.NoError(t, s.validateBlobs(b, blobs[:9], proofs[:9]))
+
+			// Should fail with 10 blobs
+			blk.Block.Body.BlobKzgCommitments = commitments[:10]
+			b, err = blocks.NewSignedBeaconBlock(blk)
+			require.NoError(t, err)
+			err = s.validateBlobs(b, blobs[:10], proofs[:10])
+			require.ErrorContains(t, "number of blobs over max, 10 > 9", err)
+		})
+	})
 }
 
 func TestGetPendingConsolidations(t *testing.T) {

beacon-chain/rpc/eth/rewards/service.go

@@ -68,7 +68,8 @@ func (rs *BlockRewardService) GetBlockRewardsData(ctx context.Context, blk inter
 			Code:    http.StatusInternalServerError,
 		}
 	}
-	st, err = coreblocks.ProcessAttesterSlashings(ctx, st, blk.Body().AttesterSlashings(), validators.SlashValidator)
+	exitInfo := validators.ExitInformation(st)
+	st, err = coreblocks.ProcessAttesterSlashings(ctx, st, blk.Body().AttesterSlashings(), exitInfo)
 	if err != nil {
 		return nil, &httputil.DefaultJsonError{
 			Message: "Could not get attester slashing rewards: " + err.Error(),
@@ -82,7 +83,7 @@ func (rs *BlockRewardService) GetBlockRewardsData(ctx context.Context, blk inter
 			Code:    http.StatusInternalServerError,
 		}
 	}
-	st, err = coreblocks.ProcessProposerSlashings(ctx, st, blk.Body().ProposerSlashings(), validators.SlashValidator)
+	st, err = coreblocks.ProcessProposerSlashings(ctx, st, blk.Body().ProposerSlashings(), exitInfo)
 	if err != nil {
 		return nil, &httputil.DefaultJsonError{
 			Message: "Could not get proposer slashing rewards: " + err.Error(),

beacon-chain/rpc/eth/validator/handlers.go

@@ -1029,8 +1029,8 @@ func (s *Server) GetProposerDuties(w http.ResponseWriter, r *http.Request) {
 			httputil.HandleError(w, fmt.Sprintf("Could not get head state: %v ", err), http.StatusInternalServerError)
 			return
 		}
-		// Advance state with empty transitions up to the requested epoch start slot for pre fulu state only. Fulu state utilizes proposer look ahead field.
-		if st.Slot() < epochStartSlot && st.Version() != version.Fulu {
+		// Notice that even for Fulu requests for the next epoch, we are only advancing the state to the start of the current epoch.
+		if st.Slot() < epochStartSlot {
 			headRoot, err := s.HeadFetcher.HeadRoot(ctx)
 			if err != nil {
 				httputil.HandleError(w, fmt.Sprintf("Could not get head root: %v ", err), http.StatusInternalServerError)

beacon-chain/rpc/eth/validator/handlers_test.go

@@ -2645,78 +2645,6 @@ func TestGetProposerDuties(t *testing.T) {
 	})
 }
 
-func TestGetProposerDuties_FuluState(t *testing.T) {
-	helpers.ClearCache()
-
-	// Create a Fulu state with slot 0 (before epoch 1 start slot which is 32)
-	fuluState, err := util.NewBeaconStateFulu()
-	require.NoError(t, err)
-	require.NoError(t, fuluState.SetSlot(0)) // Set to slot 0
-
-	// Create some validators for the test
-	depChainStart := params.BeaconConfig().MinGenesisActiveValidatorCount
-	deposits, _, err := util.DeterministicDepositsAndKeys(depChainStart)
-	require.NoError(t, err)
-
-	validators := make([]*ethpbalpha.Validator, len(deposits))
-	for i, deposit := range deposits {
-		validators[i] = &ethpbalpha.Validator{
-			PublicKey:             deposit.Data.PublicKey,
-			ActivationEpoch:       0,
-			ExitEpoch:             params.BeaconConfig().FarFutureEpoch,
-			WithdrawalCredentials: make([]byte, 32),
-		}
-	}
-	require.NoError(t, fuluState.SetValidators(validators))
-
-	// Set up block roots
-	genesis := util.NewBeaconBlock()
-	genesisRoot, err := genesis.Block.HashTreeRoot()
-	require.NoError(t, err)
-	roots := make([][]byte, fieldparams.BlockRootsLength)
-	roots[0] = genesisRoot[:]
-	require.NoError(t, fuluState.SetBlockRoots(roots))
-
-	chainSlot := primitives.Slot(0)
-	chain := &mockChain.ChainService{
-		State: fuluState, Root: genesisRoot[:], Slot: &chainSlot,
-	}
-
-	db := dbutil.SetupDB(t)
-	require.NoError(t, db.SaveGenesisBlockRoot(t.Context(), genesisRoot))
-
-	s := &Server{
-		Stater:                 &testutil.MockStater{StatesBySlot: map[primitives.Slot]state.BeaconState{0: fuluState}},
-		HeadFetcher:            chain,
-		TimeFetcher:            chain,
-		OptimisticModeFetcher:  chain,
-		SyncChecker:            &mockSync.Sync{IsSyncing: false},
-		PayloadIDCache:         cache.NewPayloadIDCache(),
-		TrackedValidatorsCache: cache.NewTrackedValidatorsCache(),
-		BeaconDB:               db,
-	}
-
-	// Request epoch 1 duties, which should require advancing from slot 0 to slot 32
-	// But for Fulu state, this advancement should be skipped
-	request := httptest.NewRequest(http.MethodGet, "http://www.example.com/eth/v1/validator/duties/proposer/{epoch}", nil)
-	request.SetPathValue("epoch", "1")
-	writer := httptest.NewRecorder()
-	writer.Body = &bytes.Buffer{}
-
-	s.GetProposerDuties(writer, request)
-	assert.Equal(t, http.StatusOK, writer.Code)
-
-	// Verify the state was not advanced - it should still be at slot 0
-	// This is the key assertion for the regression test
-	assert.Equal(t, primitives.Slot(0), fuluState.Slot(), "Fulu state should not have been advanced")
-
-	resp := &structs.GetProposerDutiesResponse{}
-	require.NoError(t, json.Unmarshal(writer.Body.Bytes(), resp))
-
-	// Should still return proposer duties despite not advancing the state
-	assert.Equal(t, true, len(resp.Data) > 0, "Should return proposer duties even without state advancement")
-}
-
 func TestGetSyncCommitteeDuties(t *testing.T) {
 	helpers.ClearCache()
 	params.SetupTestConfigCleanup(t)

beacon-chain/rpc/prysm/v1alpha1/beacon/config_test.go

@@ -19,7 +19,7 @@ func TestServer_GetBeaconConfig(t *testing.T) {
 	conf := params.BeaconConfig()
 	confType := reflect.TypeOf(conf).Elem()
 	numFields := confType.NumField()
-	
+
 	// Count only exported fields, as unexported fields are not included in the config
 	exportedFields := 0
 	for i := 0; i < numFields; i++ {

beacon-chain/rpc/prysm/v1alpha1/validator/BUILD.bazel

@@ -1,3 +1,5 @@
+# gazelle:ignore
+
 load("@prysm//tools/go:def.bzl", "go_library", "go_test")
 
 go_library(
@@ -37,6 +39,7 @@ go_library(
         "//api/client/builder:go_default_library",
         "//async/event:go_default_library",
         "//beacon-chain/blockchain:go_default_library",
+        "//beacon-chain/blockchain/kzg:go_default_library",
         "//beacon-chain/builder:go_default_library",
         "//beacon-chain/cache:go_default_library",
         "//beacon-chain/cache/depositsnapshot:go_default_library",
@@ -47,6 +50,7 @@ go_library(
         "//beacon-chain/core/feed/operation:go_default_library",
         "//beacon-chain/core/feed/state:go_default_library",
         "//beacon-chain/core/helpers:go_default_library",
+        "//beacon-chain/core/peerdas:go_default_library",
         "//beacon-chain/core/signing:go_default_library",
         "//beacon-chain/core/time:go_default_library",
         "//beacon-chain/core/transition:go_default_library",
@@ -63,8 +67,8 @@ go_library(
         "//beacon-chain/rpc/core:go_default_library",
         "//beacon-chain/startup:go_default_library",
         "//beacon-chain/state:go_default_library",
-        "//beacon-chain/state/stategen:go_default_library",
         "//beacon-chain/state/state-native:go_default_library",
+        "//beacon-chain/state/stategen:go_default_library",
         "//beacon-chain/sync:go_default_library",
         "//config/features:go_default_library",
         "//config/fieldparams:go_default_library",
@@ -81,7 +85,7 @@ go_library(
         "//crypto/rand:go_default_library",
         "//encoding/bytesutil:go_default_library",
         "//encoding/ssz:go_default_library",
-	"//genesis:go_default_library",
+        "//genesis:go_default_library",
         "//math:go_default_library",
         "//monitoring/tracing:go_default_library",
         "//monitoring/tracing/trace:go_default_library",
@@ -181,7 +185,6 @@ common_deps = [
     "@org_golang_google_protobuf//types/known/emptypb:go_default_library",
 ]
 
-# gazelle:ignore
 go_test(
     name = "go_default_test",
     timeout = "moderate",

beacon-chain/rpc/prysm/v1alpha1/validator/construct_generic_block_test.go

@@ -29,12 +29,19 @@ func TestConstructGenericBeaconBlock(t *testing.T) {
 		require.NoError(t, err)
 		r1, err := eb.Block.HashTreeRoot()
 		require.NoError(t, err)
-		result, err := vs.constructGenericBeaconBlock(b, nil, primitives.ZeroWei())
+		bundle := &enginev1.BlobsBundleV2{
+			KzgCommitments: [][]byte{{1, 2, 3}},
+			Proofs:         [][]byte{{4, 5, 6}},
+			Blobs:          [][]byte{{7, 8, 9}},
+		}
+		result, err := vs.constructGenericBeaconBlock(b, bundle, primitives.ZeroWei())
 		require.NoError(t, err)
 		r2, err := result.GetFulu().Block.HashTreeRoot()
 		require.NoError(t, err)
 		require.Equal(t, r1, r2)
 		require.Equal(t, result.IsBlinded, false)
+		require.DeepEqual(t, bundle.Blobs, result.GetFulu().GetBlobs())
+		require.DeepEqual(t, bundle.Proofs, result.GetFulu().GetKzgProofs())
 	})
 
 	// Test for Electra version

beacon-chain/rpc/prysm/v1alpha1/validator/proposer.go

@@ -15,9 +15,11 @@ import (
 	blockfeed "github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed/block"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/feed/operation"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/transition"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/kv"
 	"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/interfaces"
@@ -58,28 +60,31 @@ func (vs *Server) GetBeaconBlock(ctx context.Context, req *ethpb.BlockRequest) (
 	if err != nil {
 		log.WithError(err).Error("Could not convert slot to time")
 	}
-	log.WithFields(logrus.Fields{
-		"slot":               req.Slot,
-		"sinceSlotStartTime": time.Since(t),
-	}).Info("Begin building block")
+
+	log := log.WithField("slot", req.Slot)
+	log.WithField("sinceSlotStartTime", time.Since(t)).Info("Begin building block")
 
 	// A syncing validator should not produce a block.
 	if vs.SyncChecker.Syncing() {
+		log.Error("Fail to build block: node is syncing")
 		return nil, status.Error(codes.Unavailable, "Syncing to latest head, not ready to respond")
 	}
 	// An optimistic validator MUST NOT produce a block (i.e., sign across the DOMAIN_BEACON_PROPOSER domain).
 	if slots.ToEpoch(req.Slot) >= params.BeaconConfig().BellatrixForkEpoch {
 		if err := vs.optimisticStatus(ctx); err != nil {
+			log.WithError(err).Error("Fail to build block: node is optimistic")
 			return nil, status.Errorf(codes.Unavailable, "Validator is not ready to propose: %v", err)
 		}
 	}
 
 	head, parentRoot, err := vs.getParentState(ctx, req.Slot)
 	if err != nil {
+		log.WithError(err).Error("Fail to build block: could not get parent state")
 		return nil, err
 	}
 	sBlk, err := getEmptyBlock(req.Slot)
 	if err != nil {
+		log.WithError(err).Error("Fail to build block: could not get empty block")
 		return nil, status.Errorf(codes.Internal, "Could not prepare block: %v", err)
 	}
 	// Set slot, graffiti, randao reveal, and parent root.
@@ -101,8 +106,7 @@ func (vs *Server) GetBeaconBlock(ctx context.Context, req *ethpb.BlockRequest) (
 	}
 
 	resp, err := vs.BuildBlockParallel(ctx, sBlk, head, req.SkipMevBoost, builderBoostFactor)
-	log := log.WithFields(logrus.Fields{
-		"slot":               req.Slot,
+	log = log.WithFields(logrus.Fields{
 		"sinceSlotStartTime": time.Since(t),
 		"validator":          sBlk.Block().ProposerIndex(),
 	})
@@ -275,6 +279,11 @@ func (vs *Server) BuildBlockParallel(ctx context.Context, sBlk interfaces.Signed
 //
 // ProposeBeaconBlock handles the proposal of beacon blocks.
 func (vs *Server) ProposeBeaconBlock(ctx context.Context, req *ethpb.GenericSignedBeaconBlock) (*ethpb.ProposeResponse, error) {
+	var (
+		blobSidecars       []*ethpb.BlobSidecar
+		dataColumnSidecars []*ethpb.DataColumnSidecar
+	)
+
 	ctx, span := trace.StartSpan(ctx, "ProposerServer.ProposeBeaconBlock")
 	defer span.End()
 
@@ -300,11 +309,10 @@ func (vs *Server) ProposeBeaconBlock(ctx context.Context, req *ethpb.GenericSign
 		return &ethpb.ProposeResponse{BlockRoot: root[:]}, nil
 	}
 
-	var sidecars []*ethpb.BlobSidecar
 	if block.IsBlinded() {
-		block, sidecars, err = vs.handleBlindedBlock(ctx, block)
+		block, blobSidecars, err = vs.handleBlindedBlock(ctx, block)
 	} else if block.Version() >= version.Deneb {
-		sidecars, err = vs.blobSidecarsFromUnblindedBlock(block, req)
+		blobSidecars, dataColumnSidecars, err = vs.handleUnblindedBlock(block, req)
 	}
 	if err != nil {
 		return nil, status.Errorf(codes.Internal, "%s: %v", "handle block failed", err)
@@ -323,10 +331,9 @@ func (vs *Server) ProposeBeaconBlock(ctx context.Context, req *ethpb.GenericSign
 		errChan <- nil
 	}()
 
-	if err := vs.broadcastAndReceiveBlobs(ctx, sidecars, root); err != nil {
-		return nil, status.Errorf(codes.Internal, "Could not broadcast/receive blobs: %v", err)
+	if err := vs.broadcastAndReceiveSidecars(ctx, block, root, blobSidecars, dataColumnSidecars); err != nil {
+		return nil, status.Errorf(codes.Internal, "Could not broadcast/receive sidecars: %v", err)
 	}
-
 	wg.Wait()
 	if err := <-errChan; err != nil {
 		return nil, status.Errorf(codes.Internal, "Could not broadcast/receive block: %v", err)
@@ -335,12 +342,35 @@ func (vs *Server) ProposeBeaconBlock(ctx context.Context, req *ethpb.GenericSign
 	return &ethpb.ProposeResponse{BlockRoot: root[:]}, nil
 }
 
+// broadcastAndReceiveSidecars broadcasts and receives sidecars.
+func (vs *Server) broadcastAndReceiveSidecars(
+	ctx context.Context,
+	block interfaces.SignedBeaconBlock,
+	root [fieldparams.RootLength]byte,
+	blobSidecars []*ethpb.BlobSidecar,
+	dataColumnSideCars []*ethpb.DataColumnSidecar,
+) error {
+	if block.Version() >= version.Fulu {
+		if err := vs.broadcastAndReceiveDataColumns(ctx, dataColumnSideCars, root); err != nil {
+			return errors.Wrap(err, "broadcast and receive data columns")
+		}
+		return nil
+	}
+
+	if err := vs.broadcastAndReceiveBlobs(ctx, blobSidecars, root); err != nil {
+		return errors.Wrap(err, "broadcast and receive blobs")
+	}
+
+	return nil
+}
+
 // handleBlindedBlock processes blinded beacon blocks (pre-Fulu only).
 // Post-Fulu blinded blocks are handled directly in ProposeBeaconBlock.
 func (vs *Server) handleBlindedBlock(ctx context.Context, block interfaces.SignedBeaconBlock) (interfaces.SignedBeaconBlock, []*ethpb.BlobSidecar, error) {
 	if block.Version() < version.Bellatrix {
 		return nil, nil, errors.New("pre-Bellatrix blinded block")
 	}
+
 	if vs.BlockBuilder == nil || !vs.BlockBuilder.Configured() {
 		return nil, nil, errors.New("unconfigured block builder")
 	}
@@ -367,16 +397,34 @@ func (vs *Server) handleBlindedBlock(ctx context.Context, block interfaces.Signe
 	return copiedBlock, sidecars, nil
 }
 
-func (vs *Server) blobSidecarsFromUnblindedBlock(block interfaces.SignedBeaconBlock, req *ethpb.GenericSignedBeaconBlock) ([]*ethpb.BlobSidecar, error) {
+func (vs *Server) handleUnblindedBlock(
+	block interfaces.SignedBeaconBlock,
+	req *ethpb.GenericSignedBeaconBlock,
+) ([]*ethpb.BlobSidecar, []*ethpb.DataColumnSidecar, error) {
 	rawBlobs, proofs, err := blobsAndProofs(req)
 	if err != nil {
-		return nil, err
+		return nil, nil, err
 	}
-	return BuildBlobSidecars(block, rawBlobs, proofs)
+
+	if block.Version() >= version.Fulu {
+		dataColumnSideCars, err := peerdas.ConstructDataColumnSidecars(block, rawBlobs, proofs)
+		if err != nil {
+			return nil, nil, errors.Wrap(err, "construct data column sidecars")
+		}
+
+		return nil, dataColumnSideCars, nil
+	}
+
+	blobSidecars, err := BuildBlobSidecars(block, rawBlobs, proofs)
+	if err != nil {
+		return nil, nil, errors.Wrap(err, "build blob sidecars")
+	}
+
+	return blobSidecars, nil, nil
 }
 
 // broadcastReceiveBlock broadcasts a block and handles its reception.
-func (vs *Server) broadcastReceiveBlock(ctx context.Context, block interfaces.SignedBeaconBlock, root [32]byte) error {
+func (vs *Server) broadcastReceiveBlock(ctx context.Context, block interfaces.SignedBeaconBlock, root [fieldparams.RootLength]byte) error {
 	protoBlock, err := block.Proto()
 	if err != nil {
 		return errors.Wrap(err, "protobuf conversion failed")
@@ -392,18 +440,14 @@ func (vs *Server) broadcastReceiveBlock(ctx context.Context, block interfaces.Si
 }
 
 // broadcastAndReceiveBlobs handles the broadcasting and reception of blob sidecars.
-func (vs *Server) broadcastAndReceiveBlobs(ctx context.Context, sidecars []*ethpb.BlobSidecar, root [32]byte) error {
+func (vs *Server) broadcastAndReceiveBlobs(ctx context.Context, sidecars []*ethpb.BlobSidecar, root [fieldparams.RootLength]byte) error {
 	eg, eCtx := errgroup.WithContext(ctx)
-	for i, sc := range sidecars {
-		// Copy the iteration instance to a local variable to give each go-routine its own copy to play with.
-		// See https://golang.org/doc/faq#closures_and_goroutines for more details.
-		subIdx := i
-		sCar := sc
+	for subIdx, sc := range sidecars {
 		eg.Go(func() error {
-			if err := vs.P2P.BroadcastBlob(eCtx, uint64(subIdx), sCar); err != nil {
+			if err := vs.P2P.BroadcastBlob(eCtx, uint64(subIdx), sc); err != nil {
 				return errors.Wrap(err, "broadcast blob failed")
 			}
-			readOnlySc, err := blocks.NewROBlobWithRoot(sCar, root)
+			readOnlySc, err := blocks.NewROBlobWithRoot(sc, root)
 			if err != nil {
 				return errors.Wrap(err, "ROBlob creation failed")
 			}
@@ -421,6 +465,53 @@ func (vs *Server) broadcastAndReceiveBlobs(ctx context.Context, sidecars []*ethp
 	return eg.Wait()
 }
 
+// broadcastAndReceiveDataColumns handles the broadcasting and reception of data columns sidecars.
+func (vs *Server) broadcastAndReceiveDataColumns(
+	ctx context.Context,
+	sidecars []*ethpb.DataColumnSidecar,
+	root [fieldparams.RootLength]byte,
+) error {
+	verifiedRODataColumns := make([]blocks.VerifiedRODataColumn, 0, len(sidecars))
+	eg, _ := errgroup.WithContext(ctx)
+	for _, sidecar := range sidecars {
+		roDataColumn, err := blocks.NewRODataColumnWithRoot(sidecar, root)
+		if err != nil {
+			return errors.Wrap(err, "new read-only data column with root")
+		}
+
+		// We build this block ourselves, so we can upgrade the read only data column sidecar into a verified one.
+		verifiedRODataColumn := blocks.NewVerifiedRODataColumn(roDataColumn)
+		verifiedRODataColumns = append(verifiedRODataColumns, verifiedRODataColumn)
+
+		eg.Go(func() error {
+			// Compute the subnet index based on the column index.
+			subnet := peerdas.ComputeSubnetForDataColumnSidecar(sidecar.Index)
+
+			if err := vs.P2P.BroadcastDataColumnSidecar(root, subnet, sidecar); err != nil {
+				return errors.Wrap(err, "broadcast data column")
+			}
+
+			return nil
+		})
+	}
+
+	if err := eg.Wait(); err != nil {
+		return errors.Wrap(err, "wait for data columns to be broadcasted")
+	}
+
+	if err := vs.DataColumnReceiver.ReceiveDataColumns(verifiedRODataColumns); err != nil {
+		return errors.Wrap(err, "receive data column")
+	}
+
+	for _, verifiedRODataColumn := range verifiedRODataColumns {
+		vs.OperationNotifier.OperationFeed().Send(&feed.Event{
+			Type: operation.DataColumnSidecarReceived,
+			Data: &operation.DataColumnSidecarReceivedData{DataColumn: &verifiedRODataColumn}, // #nosec G601
+		})
+	}
+	return nil
+}
+
 // Deprecated: The gRPC API will remain the default and fully supported through v8 (expected in 2026) but will be eventually removed in favor of REST API.
 //
 // PrepareBeaconProposer caches and updates the fee recipient for the given proposer.

beacon-chain/rpc/prysm/v1alpha1/validator/proposer_altair.go

@@ -1,8 +1,10 @@
 package validator
 
 import (
+	"bytes"
 	"context"
 
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/interfaces"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
@@ -15,6 +17,7 @@ import (
 	"github.com/OffchainLabs/prysm/v6/runtime/version"
 	"github.com/OffchainLabs/prysm/v6/time/slots"
 	"github.com/pkg/errors"
+	"github.com/prysmaticlabs/go-bitfield"
 )
 
 func (vs *Server) setSyncAggregate(ctx context.Context, blk interfaces.SignedBeaconBlock) {
@@ -51,21 +54,28 @@ func (vs *Server) getSyncAggregate(ctx context.Context, slot primitives.Slot, ro
 	if vs.SyncCommitteePool == nil {
 		return nil, errors.New("sync committee pool is nil")
 	}
-	// Contributions have to match the input root
-	contributions, err := vs.SyncCommitteePool.SyncCommitteeContributions(slot)
+
+	poolContributions, err := vs.SyncCommitteePool.SyncCommitteeContributions(slot)
 	if err != nil {
 		return nil, err
 	}
-	proposerContributions := proposerSyncContributions(contributions).filterByBlockRoot(root)
+	// Contributions have to match the input root
+	proposerContributions := proposerSyncContributions(poolContributions).filterByBlockRoot(root)
 
-	// Each sync subcommittee is 128 bits and the sync committee is 512 bits for mainnet.
+	aggregatedContributions, err := vs.aggregatedSyncCommitteeMessages(ctx, slot, root, poolContributions)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not get aggregated sync committee messages")
+	}
+	proposerContributions = append(proposerContributions, aggregatedContributions...)
+
+	subcommitteeCount := params.BeaconConfig().SyncCommitteeSubnetCount
 	var bitsHolder [][]byte
-	for i := uint64(0); i < params.BeaconConfig().SyncCommitteeSubnetCount; i++ {
+	for i := uint64(0); i < subcommitteeCount; i++ {
 		bitsHolder = append(bitsHolder, ethpb.NewSyncCommitteeAggregationBits())
 	}
-	sigsHolder := make([]bls.Signature, 0, params.BeaconConfig().SyncCommitteeSize/params.BeaconConfig().SyncCommitteeSubnetCount)
+	sigsHolder := make([]bls.Signature, 0, params.BeaconConfig().SyncCommitteeSize/subcommitteeCount)
 
-	for i := uint64(0); i < params.BeaconConfig().SyncCommitteeSubnetCount; i++ {
+	for i := uint64(0); i < subcommitteeCount; i++ {
 		cs := proposerContributions.filterBySubIndex(i)
 		aggregates, err := synccontribution.Aggregate(cs)
 		if err != nil {
@@ -107,3 +117,107 @@ func (vs *Server) getSyncAggregate(ctx context.Context, slot primitives.Slot, ro
 		SyncCommitteeSignature: syncSigBytes[:],
 	}, nil
 }
+
+func (vs *Server) aggregatedSyncCommitteeMessages(
+	ctx context.Context,
+	slot primitives.Slot,
+	root [32]byte,
+	poolContributions []*ethpb.SyncCommitteeContribution,
+) ([]*ethpb.SyncCommitteeContribution, error) {
+	subcommitteeCount := params.BeaconConfig().SyncCommitteeSubnetCount
+	subcommitteeSize := params.BeaconConfig().SyncCommitteeSize / subcommitteeCount
+	sigsPerSubcommittee := make([][][]byte, subcommitteeCount)
+	bitsPerSubcommittee := make([]bitfield.Bitfield, subcommitteeCount)
+	for i := uint64(0); i < subcommitteeCount; i++ {
+		sigsPerSubcommittee[i] = make([][]byte, 0, subcommitteeSize)
+		bitsPerSubcommittee[i] = ethpb.NewSyncCommitteeAggregationBits()
+	}
+
+	// Get committee position(s) for each message's validator index.
+	scMessages, err := vs.SyncCommitteePool.SyncCommitteeMessages(slot)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not get sync committee messages")
+	}
+	messageIndices := make([]primitives.ValidatorIndex, 0, len(scMessages))
+	messageSigs := make([][]byte, 0, len(scMessages))
+	for _, msg := range scMessages {
+		if bytes.Equal(root[:], msg.BlockRoot) {
+			messageIndices = append(messageIndices, msg.ValidatorIndex)
+			messageSigs = append(messageSigs, msg.Signature)
+		}
+	}
+	st, err := vs.HeadFetcher.HeadState(ctx)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not get head state")
+	}
+	positions, err := helpers.CurrentPeriodPositions(st, messageIndices)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not get sync committee positions")
+	}
+
+	// Based on committee position(s), set the appropriate subcommittee bit and signature.
+	for i, ci := range positions {
+		for _, index := range ci {
+			k := uint64(index)
+			subnetIndex := k / subcommitteeSize
+			indexMod := k % subcommitteeSize
+
+			// Existing aggregated contributions from the pool intersecting with aggregates
+			// created from single sync committee messages can result in bit intersections
+			// that fail to produce the best possible final aggregate. Ignoring bits that are
+			// already set in pool contributions makes intersections impossible.
+			intersects := false
+			for _, poolContrib := range poolContributions {
+				if poolContrib.SubcommitteeIndex == subnetIndex && poolContrib.AggregationBits.BitAt(indexMod) {
+					intersects = true
+				}
+			}
+			if !intersects && !bitsPerSubcommittee[subnetIndex].BitAt(indexMod) {
+				bitsPerSubcommittee[subnetIndex].SetBitAt(indexMod, true)
+				sigsPerSubcommittee[subnetIndex] = append(sigsPerSubcommittee[subnetIndex], messageSigs[i])
+			}
+		}
+	}
+
+	// Aggregate.
+	result := make([]*ethpb.SyncCommitteeContribution, 0, subcommitteeCount)
+	for i := uint64(0); i < subcommitteeCount; i++ {
+		aggregatedSig := make([]byte, 96)
+		aggregatedSig[0] = 0xC0
+		if len(sigsPerSubcommittee[i]) != 0 {
+			contrib, err := aggregateSyncSubcommitteeMessages(slot, root, i, bitsPerSubcommittee[i], sigsPerSubcommittee[i])
+			if err != nil {
+				// Skip aggregating this subcommittee
+				log.WithError(err).Errorf("Could not aggregate sync messages for subcommittee %d", i)
+				continue
+			}
+			result = append(result, contrib)
+		}
+	}
+
+	return result, nil
+}
+
+func aggregateSyncSubcommitteeMessages(
+	slot primitives.Slot,
+	root [32]byte,
+	subcommitteeIndex uint64,
+	bits bitfield.Bitfield,
+	sigs [][]byte,
+) (*ethpb.SyncCommitteeContribution, error) {
+	var err error
+	uncompressedSigs := make([]bls.Signature, len(sigs))
+	for i, sig := range sigs {
+		uncompressedSigs[i], err = bls.SignatureFromBytesNoValidation(sig)
+		if err != nil {
+			return nil, errors.Wrap(err, "could not create signature from bytes")
+		}
+	}
+	return &ethpb.SyncCommitteeContribution{
+		Slot:              slot,
+		BlockRoot:         root[:],
+		SubcommitteeIndex: subcommitteeIndex,
+		AggregationBits:   bits.Bytes(),
+		Signature:         bls.AggregateSignatures(uncompressedSigs).Marshal(),
+	}, nil
+}

beacon-chain/rpc/prysm/v1alpha1/validator/proposer_altair_test.go

@@ -3,13 +3,67 @@ package validator
 import (
 	"testing"
 
+	chainmock "github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/testing"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/helpers"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/operations/synccommittee"
+	mockSync "github.com/OffchainLabs/prysm/v6/beacon-chain/sync/initial-sync/testing"
 	"github.com/OffchainLabs/prysm/v6/config/params"
 	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
+	"github.com/OffchainLabs/prysm/v6/crypto/bls"
+	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
+	"github.com/OffchainLabs/prysm/v6/testing/assert"
 	"github.com/OffchainLabs/prysm/v6/testing/require"
 	"github.com/OffchainLabs/prysm/v6/testing/util"
+	"github.com/prysmaticlabs/go-bitfield"
 )
 
+func TestProposer_GetSyncAggregate_OK(t *testing.T) {
+	st, err := util.NewBeaconStateAltair()
+	require.NoError(t, err)
+	proposerServer := &Server{
+		HeadFetcher:       &chainmock.ChainService{State: st},
+		SyncChecker:       &mockSync.Sync{IsSyncing: false},
+		SyncCommitteePool: synccommittee.NewStore(),
+	}
+
+	r := params.BeaconConfig().ZeroHash
+	conts := []*ethpb.SyncCommitteeContribution{
+		{Slot: 1, SubcommitteeIndex: 0, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b0001}, BlockRoot: r[:]},
+		{Slot: 1, SubcommitteeIndex: 0, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b1001}, BlockRoot: r[:]},
+		{Slot: 1, SubcommitteeIndex: 0, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b1110}, BlockRoot: r[:]},
+		{Slot: 1, SubcommitteeIndex: 1, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b0001}, BlockRoot: r[:]},
+		{Slot: 1, SubcommitteeIndex: 1, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b1001}, BlockRoot: r[:]},
+		{Slot: 1, SubcommitteeIndex: 1, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b1110}, BlockRoot: r[:]},
+		{Slot: 1, SubcommitteeIndex: 2, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b0001}, BlockRoot: r[:]},
+		{Slot: 1, SubcommitteeIndex: 2, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b1001}, BlockRoot: r[:]},
+		{Slot: 1, SubcommitteeIndex: 2, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b1110}, BlockRoot: r[:]},
+		{Slot: 1, SubcommitteeIndex: 3, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b0001}, BlockRoot: r[:]},
+		{Slot: 1, SubcommitteeIndex: 3, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b1001}, BlockRoot: r[:]},
+		{Slot: 1, SubcommitteeIndex: 3, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b1110}, BlockRoot: r[:]},
+		{Slot: 2, SubcommitteeIndex: 0, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b10101010}, BlockRoot: r[:]},
+		{Slot: 2, SubcommitteeIndex: 1, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b10101010}, BlockRoot: r[:]},
+		{Slot: 2, SubcommitteeIndex: 2, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b10101010}, BlockRoot: r[:]},
+		{Slot: 2, SubcommitteeIndex: 3, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b10101010}, BlockRoot: r[:]},
+	}
+
+	for _, cont := range conts {
+		require.NoError(t, proposerServer.SyncCommitteePool.SaveSyncCommitteeContribution(cont))
+	}
+
+	aggregate, err := proposerServer.getSyncAggregate(t.Context(), 1, bytesutil.ToBytes32(conts[0].BlockRoot))
+	require.NoError(t, err)
+	require.DeepEqual(t, bitfield.Bitvector32{0xf, 0xf, 0xf, 0xf}, aggregate.SyncCommitteeBits)
+
+	aggregate, err = proposerServer.getSyncAggregate(t.Context(), 2, bytesutil.ToBytes32(conts[0].BlockRoot))
+	require.NoError(t, err)
+	require.DeepEqual(t, bitfield.Bitvector32{0xaa, 0xaa, 0xaa, 0xaa}, aggregate.SyncCommitteeBits)
+
+	aggregate, err = proposerServer.getSyncAggregate(t.Context(), 3, bytesutil.ToBytes32(conts[0].BlockRoot))
+	require.NoError(t, err)
+	require.DeepEqual(t, bitfield.NewBitvector32(), aggregate.SyncCommitteeBits)
+}
+
 func TestServer_SetSyncAggregate_EmptyCase(t *testing.T) {
 	b, err := blocks.NewSignedBeaconBlock(util.NewBeaconBlockAltair())
 	require.NoError(t, err)
@@ -25,3 +79,123 @@ func TestServer_SetSyncAggregate_EmptyCase(t *testing.T) {
 	}
 	require.DeepEqual(t, want, agg)
 }
+
+func TestProposer_GetSyncAggregate_IncludesSyncCommitteeMessages(t *testing.T) {
+	// TEST SETUP
+	// - validator 0 is selected twice in subcommittee 0 (indexes [0,1])
+	// - validator 1 is selected once in subcommittee 0 (index 2)
+	// - validator 2 is selected twice in subcommittee 1 (indexes [0,1])
+	// - validator 3 is selected once in subcommittee 1 (index 2)
+	// - sync committee aggregates in the pool have index 3 set for both subcommittees
+
+	subcommitteeSize := params.BeaconConfig().SyncCommitteeSize / params.BeaconConfig().SyncCommitteeSubnetCount
+
+	helpers.ClearCache()
+	st, err := util.NewBeaconStateAltair()
+	require.NoError(t, err)
+	vals := make([]*ethpb.Validator, 4)
+	vals[0] = &ethpb.Validator{PublicKey: bytesutil.PadTo([]byte{0xf0}, 48)}
+	vals[1] = &ethpb.Validator{PublicKey: bytesutil.PadTo([]byte{0xf1}, 48)}
+	vals[2] = &ethpb.Validator{PublicKey: bytesutil.PadTo([]byte{0xf2}, 48)}
+	vals[3] = &ethpb.Validator{PublicKey: bytesutil.PadTo([]byte{0xf3}, 48)}
+	require.NoError(t, st.SetValidators(vals))
+	sc := &ethpb.SyncCommittee{
+		Pubkeys: make([][]byte, params.BeaconConfig().SyncCommitteeSize),
+	}
+	sc.Pubkeys[0] = vals[0].PublicKey
+	sc.Pubkeys[1] = vals[0].PublicKey
+	sc.Pubkeys[2] = vals[1].PublicKey
+	sc.Pubkeys[subcommitteeSize] = vals[2].PublicKey
+	sc.Pubkeys[subcommitteeSize+1] = vals[2].PublicKey
+	sc.Pubkeys[subcommitteeSize+2] = vals[3].PublicKey
+	require.NoError(t, st.SetCurrentSyncCommittee(sc))
+	proposerServer := &Server{
+		HeadFetcher:       &chainmock.ChainService{State: st},
+		SyncChecker:       &mockSync.Sync{IsSyncing: false},
+		SyncCommitteePool: synccommittee.NewStore(),
+	}
+
+	r := params.BeaconConfig().ZeroHash
+	msgs := []*ethpb.SyncCommitteeMessage{
+		{Slot: 1, BlockRoot: r[:], ValidatorIndex: 0, Signature: bls.NewAggregateSignature().Marshal()},
+		{Slot: 1, BlockRoot: r[:], ValidatorIndex: 1, Signature: bls.NewAggregateSignature().Marshal()},
+		{Slot: 1, BlockRoot: r[:], ValidatorIndex: 2, Signature: bls.NewAggregateSignature().Marshal()},
+		{Slot: 1, BlockRoot: r[:], ValidatorIndex: 3, Signature: bls.NewAggregateSignature().Marshal()},
+	}
+	for _, msg := range msgs {
+		require.NoError(t, proposerServer.SyncCommitteePool.SaveSyncCommitteeMessage(msg))
+	}
+	subcommittee0AggBits := ethpb.NewSyncCommitteeAggregationBits()
+	subcommittee0AggBits.SetBitAt(3, true)
+	subcommittee1AggBits := ethpb.NewSyncCommitteeAggregationBits()
+	subcommittee1AggBits.SetBitAt(3, true)
+	conts := []*ethpb.SyncCommitteeContribution{
+		{Slot: 1, SubcommitteeIndex: 0, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: subcommittee0AggBits, BlockRoot: r[:]},
+		{Slot: 1, SubcommitteeIndex: 1, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: subcommittee1AggBits, BlockRoot: r[:]},
+	}
+	for _, cont := range conts {
+		require.NoError(t, proposerServer.SyncCommitteePool.SaveSyncCommitteeContribution(cont))
+	}
+
+	// The final sync aggregates must have indexes [0,1,2,3] set for both subcommittees
+	sa, err := proposerServer.getSyncAggregate(t.Context(), 1, r)
+	require.NoError(t, err)
+	assert.Equal(t, true, sa.SyncCommitteeBits.BitAt(0))
+	assert.Equal(t, true, sa.SyncCommitteeBits.BitAt(1))
+	assert.Equal(t, true, sa.SyncCommitteeBits.BitAt(2))
+	assert.Equal(t, true, sa.SyncCommitteeBits.BitAt(3))
+	assert.Equal(t, true, sa.SyncCommitteeBits.BitAt(subcommitteeSize))
+	assert.Equal(t, true, sa.SyncCommitteeBits.BitAt(subcommitteeSize+1))
+	assert.Equal(t, true, sa.SyncCommitteeBits.BitAt(subcommitteeSize+2))
+	assert.Equal(t, true, sa.SyncCommitteeBits.BitAt(subcommitteeSize+3))
+}
+
+func Test_aggregatedSyncCommitteeMessages_NoIntersectionWithPoolContributions(t *testing.T) {
+	helpers.ClearCache()
+	st, err := util.NewBeaconStateAltair()
+	require.NoError(t, err)
+	vals := make([]*ethpb.Validator, 4)
+	vals[0] = &ethpb.Validator{PublicKey: bytesutil.PadTo([]byte{0xf0}, 48)}
+	vals[1] = &ethpb.Validator{PublicKey: bytesutil.PadTo([]byte{0xf1}, 48)}
+	vals[2] = &ethpb.Validator{PublicKey: bytesutil.PadTo([]byte{0xf2}, 48)}
+	vals[3] = &ethpb.Validator{PublicKey: bytesutil.PadTo([]byte{0xf3}, 48)}
+	require.NoError(t, st.SetValidators(vals))
+	sc := &ethpb.SyncCommittee{
+		Pubkeys: make([][]byte, params.BeaconConfig().SyncCommitteeSize),
+	}
+	sc.Pubkeys[0] = vals[0].PublicKey
+	sc.Pubkeys[1] = vals[1].PublicKey
+	sc.Pubkeys[2] = vals[2].PublicKey
+	sc.Pubkeys[3] = vals[3].PublicKey
+	require.NoError(t, st.SetCurrentSyncCommittee(sc))
+	proposerServer := &Server{
+		HeadFetcher:       &chainmock.ChainService{State: st},
+		SyncChecker:       &mockSync.Sync{IsSyncing: false},
+		SyncCommitteePool: synccommittee.NewStore(),
+	}
+
+	r := params.BeaconConfig().ZeroHash
+	msgs := []*ethpb.SyncCommitteeMessage{
+		{Slot: 1, BlockRoot: r[:], ValidatorIndex: 0, Signature: bls.NewAggregateSignature().Marshal()},
+		{Slot: 1, BlockRoot: r[:], ValidatorIndex: 1, Signature: bls.NewAggregateSignature().Marshal()},
+		{Slot: 1, BlockRoot: r[:], ValidatorIndex: 2, Signature: bls.NewAggregateSignature().Marshal()},
+		{Slot: 1, BlockRoot: r[:], ValidatorIndex: 3, Signature: bls.NewAggregateSignature().Marshal()},
+	}
+	for _, msg := range msgs {
+		require.NoError(t, proposerServer.SyncCommitteePool.SaveSyncCommitteeMessage(msg))
+	}
+	subcommitteeAggBits := ethpb.NewSyncCommitteeAggregationBits()
+	subcommitteeAggBits.SetBitAt(3, true)
+	cont := &ethpb.SyncCommitteeContribution{
+		Slot:              1,
+		SubcommitteeIndex: 0,
+		Signature:         bls.NewAggregateSignature().Marshal(),
+		AggregationBits:   subcommitteeAggBits,
+		BlockRoot:         r[:],
+	}
+
+	aggregated, err := proposerServer.aggregatedSyncCommitteeMessages(t.Context(), 1, r, []*ethpb.SyncCommitteeContribution{cont})
+	require.NoError(t, err)
+	require.Equal(t, 1, len(aggregated))
+	assert.Equal(t, false, aggregated[0].AggregationBits.BitAt(3))
+}

beacon-chain/rpc/prysm/v1alpha1/validator/proposer_slashings.go

@@ -4,16 +4,23 @@ 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"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 )
 
 func (vs *Server) getSlashings(ctx context.Context, head state.BeaconState) ([]*ethpb.ProposerSlashing, []ethpb.AttSlashing) {
+	var err error
+
+	exitInfo := v.ExitInformation(head)
+	if err := helpers.UpdateTotalActiveBalanceCache(head, exitInfo.TotalActiveBalance); err != nil {
+		log.WithError(err).Warn("Could not update total active balance cache")
+	}
 	proposerSlashings := vs.SlashingsPool.PendingProposerSlashings(ctx, head, false /*noLimit*/)
 	validProposerSlashings := make([]*ethpb.ProposerSlashing, 0, len(proposerSlashings))
 	for _, slashing := range proposerSlashings {
-		_, err := blocks.ProcessProposerSlashing(ctx, head, slashing, v.SlashValidator)
+		_, err = blocks.ProcessProposerSlashing(ctx, head, slashing, exitInfo)
 		if err != nil {
 			log.WithError(err).Warn("Could not validate proposer slashing for block inclusion")
 			continue
@@ -23,7 +30,7 @@ func (vs *Server) getSlashings(ctx context.Context, head state.BeaconState) ([]*
 	attSlashings := vs.SlashingsPool.PendingAttesterSlashings(ctx, head, false /*noLimit*/)
 	validAttSlashings := make([]ethpb.AttSlashing, 0, len(attSlashings))
 	for _, slashing := range attSlashings {
-		_, err := blocks.ProcessAttesterSlashing(ctx, head, slashing, v.SlashValidator)
+		_, err = blocks.ProcessAttesterSlashing(ctx, head, slashing, exitInfo)
 		if err != nil {
 			log.WithError(err).Warn("Could not validate attester slashing for block inclusion")
 			continue

beacon-chain/rpc/prysm/v1alpha1/validator/proposer_test.go

@@ -6,6 +6,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/kzg"
 	mock "github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/testing"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/builder"
 	builderTest "github.com/OffchainLabs/prysm/v6/beacon-chain/builder/testing"
@@ -894,6 +895,9 @@ func injectSlashings(t *testing.T, st state.BeaconState, keys []bls.SecretKey, s
 }
 
 func TestProposer_ProposeBlock_OK(t *testing.T) {
+	// Initialize KZG for Fulu blocks
+	require.NoError(t, kzg.Start())
+
 	tests := []struct {
 		name       string
 		block      func([32]byte) *ethpb.GenericSignedBeaconBlock
@@ -1098,6 +1102,131 @@ func TestProposer_ProposeBlock_OK(t *testing.T) {
 			},
 			err: "blob KZG commitments don't match number of blobs or KZG proofs",
 		},
+		{
+			name: "fulu block no blob",
+			block: func(parent [32]byte) *ethpb.GenericSignedBeaconBlock {
+				sb := &ethpb.SignedBeaconBlockContentsFulu{
+					Block: &ethpb.SignedBeaconBlockFulu{
+						Block: &ethpb.BeaconBlockElectra{Slot: 5, ParentRoot: parent[:], Body: util.HydrateBeaconBlockBodyElectra(&ethpb.BeaconBlockBodyElectra{})},
+					},
+				}
+				blk := &ethpb.GenericSignedBeaconBlock_Fulu{Fulu: sb}
+				return &ethpb.GenericSignedBeaconBlock{Block: blk, IsBlinded: false}
+			},
+		},
+		{
+			name: "fulu block with single blob and cell proofs",
+			block: func(parent [32]byte) *ethpb.GenericSignedBeaconBlock {
+				numberOfColumns := uint64(128)
+				// For Fulu, we have cell proofs (blobs * numberOfColumns)
+				cellProofs := make([][]byte, numberOfColumns)
+				for i := uint64(0); i < numberOfColumns; i++ {
+					cellProofs[i] = bytesutil.PadTo([]byte{byte(i)}, 48)
+				}
+				// Blob must be exactly 131072 bytes
+				blob := make([]byte, 131072)
+				blob[0] = 0x01
+				sb := &ethpb.SignedBeaconBlockContentsFulu{
+					Block: &ethpb.SignedBeaconBlockFulu{
+						Block: &ethpb.BeaconBlockElectra{
+							Slot: 5, ParentRoot: parent[:],
+							Body: util.HydrateBeaconBlockBodyElectra(&ethpb.BeaconBlockBodyElectra{
+								BlobKzgCommitments: [][]byte{bytesutil.PadTo([]byte("kc"), 48)},
+							}),
+						},
+					},
+					KzgProofs: cellProofs,
+					Blobs:     [][]byte{blob},
+				}
+				blk := &ethpb.GenericSignedBeaconBlock_Fulu{Fulu: sb}
+				return &ethpb.GenericSignedBeaconBlock{Block: blk, IsBlinded: false}
+			},
+		},
+		{
+			name: "fulu block with multiple blobs and cell proofs",
+			block: func(parent [32]byte) *ethpb.GenericSignedBeaconBlock {
+				numberOfColumns := uint64(128)
+				blobCount := 3
+				// For Fulu, we have cell proofs (blobs * numberOfColumns)
+				cellProofs := make([][]byte, uint64(blobCount)*numberOfColumns)
+				for i := range cellProofs {
+					cellProofs[i] = bytesutil.PadTo([]byte{byte(i % 256)}, 48)
+				}
+				// Create properly sized blobs (131072 bytes each)
+				blobs := make([][]byte, blobCount)
+				for i := 0; i < blobCount; i++ {
+					blob := make([]byte, 131072)
+					blob[0] = byte(i + 1)
+					blobs[i] = blob
+				}
+				sb := &ethpb.SignedBeaconBlockContentsFulu{
+					Block: &ethpb.SignedBeaconBlockFulu{
+						Block: &ethpb.BeaconBlockElectra{
+							Slot: 5, ParentRoot: parent[:],
+							Body: util.HydrateBeaconBlockBodyElectra(&ethpb.BeaconBlockBodyElectra{
+								BlobKzgCommitments: [][]byte{
+									bytesutil.PadTo([]byte("kc"), 48),
+									bytesutil.PadTo([]byte("kc1"), 48),
+									bytesutil.PadTo([]byte("kc2"), 48),
+								},
+							}),
+						},
+					},
+					KzgProofs: cellProofs,
+					Blobs:     blobs,
+				}
+				blk := &ethpb.GenericSignedBeaconBlock_Fulu{Fulu: sb}
+				return &ethpb.GenericSignedBeaconBlock{Block: blk, IsBlinded: false}
+			},
+		},
+		{
+			name: "fulu block wrong cell proof count (should be blobs * 128)",
+			block: func(parent [32]byte) *ethpb.GenericSignedBeaconBlock {
+				// Wrong number of cell proofs - should be 2 * 128 = 256, but providing only 2
+				// Create properly sized blobs
+				blob1 := make([]byte, 131072)
+				blob1[0] = 0x01
+				blob2 := make([]byte, 131072)
+				blob2[0] = 0x02
+				sb := &ethpb.SignedBeaconBlockContentsFulu{
+					Block: &ethpb.SignedBeaconBlockFulu{
+						Block: &ethpb.BeaconBlockElectra{
+							Slot: 5, ParentRoot: parent[:],
+							Body: util.HydrateBeaconBlockBodyElectra(&ethpb.BeaconBlockBodyElectra{
+								BlobKzgCommitments: [][]byte{
+									bytesutil.PadTo([]byte("kc"), 48),
+									bytesutil.PadTo([]byte("kc1"), 48),
+								},
+							}),
+						},
+					},
+					KzgProofs: [][]byte{{0x01}, {0x02}}, // Wrong: should be 256 cell proofs
+					Blobs:     [][]byte{blob1, blob2},
+				}
+				blk := &ethpb.GenericSignedBeaconBlock_Fulu{Fulu: sb}
+				return &ethpb.GenericSignedBeaconBlock{Block: blk, IsBlinded: false}
+			},
+			err: "blobs and cells proofs mismatch",
+		},
+		{
+			name: "blind fulu block with blob commitments",
+			block: func(parent [32]byte) *ethpb.GenericSignedBeaconBlock {
+				blockToPropose := util.NewBlindedBeaconBlockFulu()
+				blockToPropose.Message.Slot = 5
+				blockToPropose.Message.ParentRoot = parent[:]
+				txRoot, err := ssz.TransactionsRoot([][]byte{})
+				require.NoError(t, err)
+				withdrawalsRoot, err := ssz.WithdrawalSliceRoot([]*enginev1.Withdrawal{}, fieldparams.MaxWithdrawalsPerPayload)
+				require.NoError(t, err)
+				blockToPropose.Message.Body.ExecutionPayloadHeader.TransactionsRoot = txRoot[:]
+				blockToPropose.Message.Body.ExecutionPayloadHeader.WithdrawalsRoot = withdrawalsRoot[:]
+				blockToPropose.Message.Body.BlobKzgCommitments = [][]byte{bytesutil.PadTo([]byte{0x01}, 48)}
+				blk := &ethpb.GenericSignedBeaconBlock_BlindedFulu{BlindedFulu: blockToPropose}
+				return &ethpb.GenericSignedBeaconBlock{Block: blk}
+			},
+			useBuilder: true,
+			err:        "commitment value doesn't match block", // Known issue with mock builder cell proof mismatch
+		},
 	}
 
 	for _, tt := range tests {
@@ -1111,15 +1240,29 @@ func TestProposer_ProposeBlock_OK(t *testing.T) {
 
 			c := &mock.ChainService{Root: bsRoot[:], State: beaconState}
 			db := dbutil.SetupDB(t)
+			// Create cell proofs for Fulu blocks (128 proofs per blob)
+			numberOfColumns := uint64(128)
+			cellProofs := make([][]byte, numberOfColumns)
+			for i := uint64(0); i < numberOfColumns; i++ {
+				cellProofs[i] = bytesutil.PadTo([]byte{byte(i)}, 48)
+			}
+			// Create properly sized blob for mock builder
+			mockBlob := make([]byte, 131072)
+			mockBlob[0] = 0x03
+			// Use the same commitment as in the blind block test
+			mockCommitment := bytesutil.PadTo([]byte{0x01}, 48)
+
 			proposerServer := &Server{
 				BlockReceiver: c,
 				BlockNotifier: c.BlockNotifier(),
 				P2P:           mockp2p.NewTestP2P(t),
 				BlockBuilder: &builderTest.MockBuilderService{HasConfigured: tt.useBuilder, PayloadCapella: emptyPayloadCapella(), PayloadDeneb: emptyPayloadDeneb(),
-					BlobBundle: &enginev1.BlobsBundle{KzgCommitments: [][]byte{bytesutil.PadTo([]byte{0x01}, 48)}, Proofs: [][]byte{{0x02}}, Blobs: [][]byte{{0x03}}}},
-				BeaconDB:          db,
-				BlobReceiver:      c,
-				OperationNotifier: c.OperationNotifier(),
+					BlobBundle:   &enginev1.BlobsBundle{KzgCommitments: [][]byte{mockCommitment}, Proofs: [][]byte{{0x02}}, Blobs: [][]byte{{0x03}}},
+					BlobBundleV2: &enginev1.BlobsBundleV2{KzgCommitments: [][]byte{mockCommitment}, Proofs: cellProofs, Blobs: [][]byte{mockBlob}}},
+				BeaconDB:           db,
+				BlobReceiver:       c,
+				DataColumnReceiver: c, // Add DataColumnReceiver for Fulu blocks
+				OperationNotifier:  c.OperationNotifier(),
 			}
 			blockToPropose := tt.block(bsRoot)
 			res, err := proposerServer.ProposeBeaconBlock(t.Context(), blockToPropose)
@@ -2953,49 +3096,6 @@ func TestProposer_DeleteAttsInPool_Aggregated(t *testing.T) {
 	assert.Equal(t, 0, len(atts), "Did not delete unaggregated attestation")
 }
 
-func TestProposer_GetSyncAggregate_OK(t *testing.T) {
-	proposerServer := &Server{
-		SyncChecker:       &mockSync.Sync{IsSyncing: false},
-		SyncCommitteePool: synccommittee.NewStore(),
-	}
-
-	r := params.BeaconConfig().ZeroHash
-	conts := []*ethpb.SyncCommitteeContribution{
-		{Slot: 1, SubcommitteeIndex: 0, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b0001}, BlockRoot: r[:]},
-		{Slot: 1, SubcommitteeIndex: 0, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b1001}, BlockRoot: r[:]},
-		{Slot: 1, SubcommitteeIndex: 0, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b1110}, BlockRoot: r[:]},
-		{Slot: 1, SubcommitteeIndex: 1, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b0001}, BlockRoot: r[:]},
-		{Slot: 1, SubcommitteeIndex: 1, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b1001}, BlockRoot: r[:]},
-		{Slot: 1, SubcommitteeIndex: 1, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b1110}, BlockRoot: r[:]},
-		{Slot: 1, SubcommitteeIndex: 2, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b0001}, BlockRoot: r[:]},
-		{Slot: 1, SubcommitteeIndex: 2, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b1001}, BlockRoot: r[:]},
-		{Slot: 1, SubcommitteeIndex: 2, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b1110}, BlockRoot: r[:]},
-		{Slot: 1, SubcommitteeIndex: 3, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b0001}, BlockRoot: r[:]},
-		{Slot: 1, SubcommitteeIndex: 3, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b1001}, BlockRoot: r[:]},
-		{Slot: 1, SubcommitteeIndex: 3, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b1110}, BlockRoot: r[:]},
-		{Slot: 2, SubcommitteeIndex: 0, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b10101010}, BlockRoot: r[:]},
-		{Slot: 2, SubcommitteeIndex: 1, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b10101010}, BlockRoot: r[:]},
-		{Slot: 2, SubcommitteeIndex: 2, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b10101010}, BlockRoot: r[:]},
-		{Slot: 2, SubcommitteeIndex: 3, Signature: bls.NewAggregateSignature().Marshal(), AggregationBits: []byte{0b10101010}, BlockRoot: r[:]},
-	}
-
-	for _, cont := range conts {
-		require.NoError(t, proposerServer.SyncCommitteePool.SaveSyncCommitteeContribution(cont))
-	}
-
-	aggregate, err := proposerServer.getSyncAggregate(t.Context(), 1, bytesutil.ToBytes32(conts[0].BlockRoot))
-	require.NoError(t, err)
-	require.DeepEqual(t, bitfield.Bitvector32{0xf, 0xf, 0xf, 0xf}, aggregate.SyncCommitteeBits)
-
-	aggregate, err = proposerServer.getSyncAggregate(t.Context(), 2, bytesutil.ToBytes32(conts[0].BlockRoot))
-	require.NoError(t, err)
-	require.DeepEqual(t, bitfield.Bitvector32{0xaa, 0xaa, 0xaa, 0xaa}, aggregate.SyncCommitteeBits)
-
-	aggregate, err = proposerServer.getSyncAggregate(t.Context(), 3, bytesutil.ToBytes32(conts[0].BlockRoot))
-	require.NoError(t, err)
-	require.DeepEqual(t, bitfield.NewBitvector32(), aggregate.SyncCommitteeBits)
-}
-
 func TestProposer_PrepareBeaconProposer(t *testing.T) {
 	type args struct {
 		request *ethpb.PrepareBeaconProposerRequest

beacon-chain/rpc/prysm/v1alpha1/validator/server.go

@@ -69,6 +69,7 @@ type Server struct {
 	SyncCommitteePool       synccommittee.Pool
 	BlockReceiver           blockchain.BlockReceiver
 	BlobReceiver            blockchain.BlobReceiver
+	DataColumnReceiver      blockchain.DataColumnReceiver
 	MockEth1Votes           bool
 	Eth1BlockFetcher        execution.POWBlockFetcher
 	PendingDepositsFetcher  depositsnapshot.PendingDepositsFetcher

beacon-chain/rpc/service.go

@@ -89,6 +89,7 @@ type Config struct {
 	AttestationReceiver       blockchain.AttestationReceiver
 	BlockReceiver             blockchain.BlockReceiver
 	BlobReceiver              blockchain.BlobReceiver
+	DataColumnReceiver        blockchain.DataColumnReceiver
 	ExecutionChainService     execution.Chain
 	ChainStartFetcher         execution.ChainStartFetcher
 	ExecutionChainInfoFetcher execution.ChainInfoFetcher
@@ -120,6 +121,7 @@ type Config struct {
 	Router                    *http.ServeMux
 	ClockWaiter               startup.ClockWaiter
 	BlobStorage               *filesystem.BlobStorage
+	DataColumnStorage         *filesystem.DataColumnStorage
 	TrackedValidatorsCache    *cache.TrackedValidatorsCache
 	PayloadIDCache            *cache.PayloadIDCache
 	LCStore                   *lightClient.Store
@@ -196,6 +198,7 @@ func NewService(ctx context.Context, cfg *Config) *Service {
 		ChainInfoFetcher:   s.cfg.ChainInfoFetcher,
 		GenesisTimeFetcher: s.cfg.GenesisTimeFetcher,
 		BlobStorage:        s.cfg.BlobStorage,
+		DataColumnStorage:  s.cfg.DataColumnStorage,
 	}
 	rewardFetcher := &rewards.BlockRewardService{Replayer: ch, DB: s.cfg.BeaconDB}
 	coreService := &core.Service{
@@ -236,6 +239,7 @@ func NewService(ctx context.Context, cfg *Config) *Service {
 		P2P:                     s.cfg.Broadcaster,
 		BlockReceiver:           s.cfg.BlockReceiver,
 		BlobReceiver:            s.cfg.BlobReceiver,
+		DataColumnReceiver:      s.cfg.DataColumnReceiver,
 		MockEth1Votes:           s.cfg.MockEth1Votes,
 		Eth1BlockFetcher:        s.cfg.ExecutionChainService,
 		PendingDepositsFetcher:  s.cfg.PendingDepositFetcher,

beacon-chain/rpc/testutil/BUILD.bazel

@@ -8,6 +8,7 @@ go_library(
         "mock_blocker.go",
         "mock_exec_chain_info_fetcher.go",
         "mock_genesis_timefetcher.go",
+        "mock_sidecars.go",
         "mock_stater.go",
     ],
     importpath = "github.com/OffchainLabs/prysm/v6/beacon-chain/rpc/testutil",

beacon-chain/rpc/testutil/mock_sidecars.go

@@ -0,0 +1,44 @@
+package testutil
+
+import ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
+
+// CreateDataColumnSidecar generates a filled dummy data column sidecar
+func CreateDataColumnSidecar(index uint64, data []byte) *ethpb.DataColumnSidecar {
+	return &ethpb.DataColumnSidecar{
+		Index:  index,
+		Column: [][]byte{data},
+		SignedBlockHeader: &ethpb.SignedBeaconBlockHeader{
+			Header: &ethpb.BeaconBlockHeader{
+				Slot:          1,
+				ProposerIndex: 1,
+				ParentRoot:    make([]byte, 32),
+				StateRoot:     make([]byte, 32),
+				BodyRoot:      make([]byte, 32),
+			},
+			Signature: make([]byte, 96),
+		},
+		KzgCommitments:               [][]byte{make([]byte, 48)},
+		KzgProofs:                    [][]byte{make([]byte, 48)},
+		KzgCommitmentsInclusionProof: [][]byte{make([]byte, 32)},
+	}
+}
+
+// CreateBlobSidecar generates a filled dummy data blob sidecar
+func CreateBlobSidecar(index uint64, blob []byte) *ethpb.BlobSidecar {
+	return &ethpb.BlobSidecar{
+		Index: index,
+		Blob:  blob,
+		SignedBlockHeader: &ethpb.SignedBeaconBlockHeader{
+			Header: &ethpb.BeaconBlockHeader{
+				Slot:          1,
+				ProposerIndex: 1,
+				ParentRoot:    make([]byte, 32),
+				StateRoot:     make([]byte, 32),
+				BodyRoot:      make([]byte, 32),
+			},
+			Signature: make([]byte, 96),
+		},
+		KzgCommitment: make([]byte, 48),
+		KzgProof:      make([]byte, 48),
+	}
+}

beacon-chain/startup/clock.go

@@ -67,6 +67,13 @@ func WithNower(n Nower) ClockOpt {
 	}
 }
 
+// WithTimeAsNow will create a Nower based on the given time.Time and set it as the Now() implementation.
+func WithTimeAsNow(t time.Time) ClockOpt {
+	return func(g *Clock) {
+		g.now = func() time.Time { return t }
+	}
+}
+
 // NewClock constructs a Clock value from a genesis timestamp (t) and a Genesis Validator Root (vr).
 // The WithNower ClockOpt can be used in tests to specify an alternate `time.Now` implementation,
 // for instance to return a value for `Now` spanning a certain number of slots from genesis time, to control the current slot.

beacon-chain/state/interfaces.go

@@ -265,6 +265,7 @@ type WriteOnlyEth1Data interface {
 	AppendEth1DataVotes(val *ethpb.Eth1Data) error
 	SetEth1DepositIndex(val uint64) error
 	ExitEpochAndUpdateChurn(exitBalance primitives.Gwei) (primitives.Epoch, error)
+	ExitEpochAndUpdateChurnForTotalBal(totalActiveBalance primitives.Gwei, exitBalance primitives.Gwei) (primitives.Epoch, error)
 }
 
 // WriteOnlyValidators defines a struct which only has write access to validators methods.

beacon-chain/state/state-native/setters_churn.go

@@ -44,11 +44,27 @@ func (b *BeaconState) ExitEpochAndUpdateChurn(exitBalance primitives.Gwei) (prim
 		return 0, err
 	}
 
+	return b.exitEpochAndUpdateChurn(primitives.Gwei(activeBal), exitBalance)
+}
+
+// ExitEpochAndUpdateChurnForTotalBal has the same functionality as ExitEpochAndUpdateChurn,
+// the only difference being how total active balance is obtained. In ExitEpochAndUpdateChurn
+// it is calculated inside the function and in ExitEpochAndUpdateChurnForTotalBal it's a
+// function argument.
+func (b *BeaconState) ExitEpochAndUpdateChurnForTotalBal(totalActiveBalance primitives.Gwei, exitBalance primitives.Gwei) (primitives.Epoch, error) {
+	if b.version < version.Electra {
+		return 0, errNotSupported("ExitEpochAndUpdateChurnForTotalBal", b.version)
+	}
+
+	return b.exitEpochAndUpdateChurn(totalActiveBalance, exitBalance)
+}
+
+func (b *BeaconState) exitEpochAndUpdateChurn(totalActiveBalance primitives.Gwei, exitBalance primitives.Gwei) (primitives.Epoch, error) {
 	b.lock.Lock()
 	defer b.lock.Unlock()
 
 	earliestExitEpoch := max(b.earliestExitEpoch, helpers.ActivationExitEpoch(slots.ToEpoch(b.slot)))
-	perEpochChurn := helpers.ActivationExitChurnLimit(primitives.Gwei(activeBal)) // Guaranteed to be non-zero.
+	perEpochChurn := helpers.ActivationExitChurnLimit(totalActiveBalance) // Guaranteed to be non-zero.
 
 	// New epoch for exits
 	var exitBalanceToConsume primitives.Gwei

beacon-chain/sync/BUILD.bazel

@@ -5,9 +5,9 @@ go_library(
     srcs = [
         "batch_verifier.go",
         "block_batcher.go",
-        "broadcast_bls_changes.go",
         "context.go",
         "custody.go",
+        "data_column_sidecars.go",
         "data_columns_reconstruct.go",
         "deadlines.go",
         "decode_pubsub.go",
@@ -164,9 +164,9 @@ go_test(
         "batch_verifier_test.go",
         "blobs_test.go",
         "block_batcher_test.go",
-        "broadcast_bls_changes_test.go",
         "context_test.go",
         "custody_test.go",
+        "data_column_sidecars_test.go",
         "data_columns_reconstruct_test.go",
         "decode_pubsub_test.go",
         "error_test.go",
@@ -192,6 +192,7 @@ go_test(
         "slot_aware_cache_test.go",
         "subscriber_beacon_aggregate_proof_test.go",
         "subscriber_beacon_blocks_test.go",
+        "subscriber_data_column_sidecar_test.go",
         "subscriber_test.go",
         "subscription_topic_handler_test.go",
         "sync_fuzz_test.go",
@@ -264,6 +265,7 @@ go_test(
         "//crypto/rand:go_default_library",
         "//encoding/bytesutil:go_default_library",
         "//encoding/ssz/equality:go_default_library",
+        "//genesis:go_default_library",
         "//proto/engine/v1:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
         "//proto/prysm/v1alpha1/attestation:go_default_library",
@@ -281,6 +283,7 @@ go_test(
         "@com_github_golang_snappy//:go_default_library",
         "@com_github_libp2p_go_libp2p//:go_default_library",
         "@com_github_libp2p_go_libp2p//core:go_default_library",
+        "@com_github_libp2p_go_libp2p//core/crypto:go_default_library",
         "@com_github_libp2p_go_libp2p//core/network:go_default_library",
         "@com_github_libp2p_go_libp2p//core/peer:go_default_library",
         "@com_github_libp2p_go_libp2p//core/protocol:go_default_library",

beacon-chain/sync/backfill/blobs.go

@@ -91,9 +91,7 @@ func (bs *blobSync) validateNext(rb blocks.ROBlob) error {
 		return err
 	}
 
-	sc := blocks.NewSidecarFromBlobSidecar(rb)
-
-	if err := bs.store.Persist(bs.current, sc); err != nil {
+	if err := bs.store.Persist(bs.current, rb); err != nil {
 		return err
 	}
 

beacon-chain/sync/broadcast_bls_changes.go

@@ -1,88 +0,0 @@
-package sync
-
-import (
-	"context"
-	"time"
-
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/blocks"
-	"github.com/OffchainLabs/prysm/v6/config/params"
-	types "github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
-	"github.com/OffchainLabs/prysm/v6/crypto/rand"
-	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
-	"github.com/OffchainLabs/prysm/v6/time/slots"
-)
-
-const broadcastBLSChangesRateLimit = 128
-
-// This routine broadcasts known BLS changes at the Capella fork.
-func (s *Service) broadcastBLSChanges(currSlot types.Slot) {
-	capellaSlotStart, err := slots.EpochStart(params.BeaconConfig().CapellaForkEpoch)
-	if err != nil {
-		// only possible error is an overflow, so we exit early from the method
-		return
-	}
-	if currSlot != capellaSlotStart {
-		return
-	}
-	changes, err := s.cfg.blsToExecPool.PendingBLSToExecChanges()
-	if err != nil {
-		log.WithError(err).Error("could not get BLS to execution changes")
-	}
-	if len(changes) == 0 {
-		return
-	}
-	source := rand.NewGenerator()
-	length := len(changes)
-	broadcastChanges := make([]*ethpb.SignedBLSToExecutionChange, length)
-	for i := 0; i < length; i++ {
-		idx := source.Intn(len(changes))
-		broadcastChanges[i] = changes[idx]
-		changes = append(changes[:idx], changes[idx+1:]...)
-	}
-
-	go s.rateBLSChanges(s.ctx, broadcastChanges)
-}
-
-func (s *Service) broadcastBLSBatch(ctx context.Context, ptr *[]*ethpb.SignedBLSToExecutionChange) {
-	limit := broadcastBLSChangesRateLimit
-	if len(*ptr) < broadcastBLSChangesRateLimit {
-		limit = len(*ptr)
-	}
-	st, err := s.cfg.chain.HeadStateReadOnly(ctx)
-	if err != nil {
-		log.WithError(err).Error("could not get head state")
-		return
-	}
-	for _, ch := range (*ptr)[:limit] {
-		if ch != nil {
-			_, err := blocks.ValidateBLSToExecutionChange(st, ch)
-			if err != nil {
-				log.WithError(err).Error("could not validate BLS to execution change")
-				continue
-			}
-			if err := s.cfg.p2p.Broadcast(ctx, ch); err != nil {
-				log.WithError(err).Error("could not broadcast BLS to execution changes.")
-			}
-		}
-	}
-	*ptr = (*ptr)[limit:]
-}
-
-func (s *Service) rateBLSChanges(ctx context.Context, changes []*ethpb.SignedBLSToExecutionChange) {
-	s.broadcastBLSBatch(ctx, &changes)
-	if len(changes) == 0 {
-		return
-	}
-	ticker := time.NewTicker(500 * time.Millisecond)
-	for {
-		select {
-		case <-s.ctx.Done():
-			return
-		case <-ticker.C:
-			s.broadcastBLSBatch(ctx, &changes)
-			if len(changes) == 0 {
-				return
-			}
-		}
-	}
-}

beacon-chain/sync/broadcast_bls_changes_test.go

@@ -1,157 +0,0 @@
-package sync
-
-import (
-	"testing"
-	"time"
-
-	mockChain "github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain/testing"
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/signing"
-	testingdb "github.com/OffchainLabs/prysm/v6/beacon-chain/db/testing"
-	doublylinkedtree "github.com/OffchainLabs/prysm/v6/beacon-chain/forkchoice/doubly-linked-tree"
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/operations/blstoexec"
-	mockp2p "github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/testing"
-	"github.com/OffchainLabs/prysm/v6/beacon-chain/state/stategen"
-	mockSync "github.com/OffchainLabs/prysm/v6/beacon-chain/sync/initial-sync/testing"
-	"github.com/OffchainLabs/prysm/v6/config/params"
-	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
-	"github.com/OffchainLabs/prysm/v6/encoding/bytesutil"
-	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
-	"github.com/OffchainLabs/prysm/v6/testing/assert"
-	"github.com/OffchainLabs/prysm/v6/testing/require"
-	"github.com/OffchainLabs/prysm/v6/testing/util"
-	"github.com/OffchainLabs/prysm/v6/time/slots"
-	logTest "github.com/sirupsen/logrus/hooks/test"
-)
-
-func TestBroadcastBLSChanges(t *testing.T) {
-	params.SetupTestConfigCleanup(t)
-	c := params.BeaconConfig()
-	c.CapellaForkEpoch = c.BellatrixForkEpoch.Add(2)
-	params.OverrideBeaconConfig(c)
-	chainService := &mockChain.ChainService{
-		Genesis:        time.Now(),
-		ValidatorsRoot: [32]byte{'A'},
-	}
-	s := NewService(t.Context(),
-		WithP2P(mockp2p.NewTestP2P(t)),
-		WithInitialSync(&mockSync.Sync{IsSyncing: false}),
-		WithChainService(chainService),
-		WithOperationNotifier(chainService.OperationNotifier()),
-		WithBlsToExecPool(blstoexec.NewPool()),
-	)
-	var emptySig [96]byte
-	s.cfg.blsToExecPool.InsertBLSToExecChange(&ethpb.SignedBLSToExecutionChange{
-		Message: &ethpb.BLSToExecutionChange{
-			ValidatorIndex:     10,
-			FromBlsPubkey:      make([]byte, 48),
-			ToExecutionAddress: make([]byte, 20),
-		},
-		Signature: emptySig[:],
-	})
-
-	capellaStart, err := slots.EpochStart(params.BeaconConfig().CapellaForkEpoch)
-	require.NoError(t, err)
-	s.broadcastBLSChanges(capellaStart + 1)
-}
-
-func TestRateBLSChanges(t *testing.T) {
-	logHook := logTest.NewGlobal()
-	params.SetupTestConfigCleanup(t)
-	c := params.BeaconConfig()
-	c.CapellaForkEpoch = c.BellatrixForkEpoch.Add(2)
-	params.OverrideBeaconConfig(c)
-	chainService := &mockChain.ChainService{
-		Genesis:        time.Now(),
-		ValidatorsRoot: [32]byte{'A'},
-	}
-	p1 := mockp2p.NewTestP2P(t)
-	s := NewService(t.Context(),
-		WithP2P(p1),
-		WithInitialSync(&mockSync.Sync{IsSyncing: false}),
-		WithChainService(chainService),
-		WithOperationNotifier(chainService.OperationNotifier()),
-		WithBlsToExecPool(blstoexec.NewPool()),
-	)
-	beaconDB := testingdb.SetupDB(t)
-	s.cfg.stateGen = stategen.New(beaconDB, doublylinkedtree.New())
-	s.cfg.beaconDB = beaconDB
-	s.initCaches()
-	st, keys := util.DeterministicGenesisStateCapella(t, 256)
-	s.cfg.chain = &mockChain.ChainService{
-		ValidatorsRoot: [32]byte{'A'},
-		Genesis:        time.Now().Add(-time.Second * time.Duration(params.BeaconConfig().SecondsPerSlot) * time.Duration(10)),
-		State:          st,
-	}
-
-	for i := 0; i < 200; i++ {
-		message := &ethpb.BLSToExecutionChange{
-			ValidatorIndex:     primitives.ValidatorIndex(i),
-			FromBlsPubkey:      keys[i+1].PublicKey().Marshal(),
-			ToExecutionAddress: bytesutil.PadTo([]byte("address"), 20),
-		}
-		epoch := params.BeaconConfig().CapellaForkEpoch + 1
-		domain, err := signing.Domain(st.Fork(), epoch, params.BeaconConfig().DomainBLSToExecutionChange, st.GenesisValidatorsRoot())
-		assert.NoError(t, err)
-		htr, err := signing.Data(message.HashTreeRoot, domain)
-		assert.NoError(t, err)
-		signed := &ethpb.SignedBLSToExecutionChange{
-			Message:   message,
-			Signature: keys[i+1].Sign(htr[:]).Marshal(),
-		}
-
-		s.cfg.blsToExecPool.InsertBLSToExecChange(signed)
-	}
-
-	require.Equal(t, false, p1.BroadcastCalled.Load())
-	slot, err := slots.EpochStart(params.BeaconConfig().CapellaForkEpoch)
-	require.NoError(t, err)
-	s.broadcastBLSChanges(slot)
-	time.Sleep(100 * time.Millisecond) // Need a sleep for the go routine to be ready
-	require.Equal(t, true, p1.BroadcastCalled.Load())
-	require.LogsDoNotContain(t, logHook, "could not")
-
-	p1.BroadcastCalled.Store(false)
-	time.Sleep(500 * time.Millisecond) // Need a sleep for the second batch to be broadcast
-	require.Equal(t, true, p1.BroadcastCalled.Load())
-	require.LogsDoNotContain(t, logHook, "could not")
-}
-
-func TestBroadcastBLSBatch_changes_slice(t *testing.T) {
-	message := &ethpb.BLSToExecutionChange{
-		FromBlsPubkey:      make([]byte, 48),
-		ToExecutionAddress: make([]byte, 20),
-	}
-	signed := &ethpb.SignedBLSToExecutionChange{
-		Message:   message,
-		Signature: make([]byte, 96),
-	}
-	changes := make([]*ethpb.SignedBLSToExecutionChange, 200)
-	for i := 0; i < len(changes); i++ {
-		changes[i] = signed
-	}
-	p1 := mockp2p.NewTestP2P(t)
-	chainService := &mockChain.ChainService{
-		Genesis:        time.Now(),
-		ValidatorsRoot: [32]byte{'A'},
-	}
-	s := NewService(t.Context(),
-		WithP2P(p1),
-		WithInitialSync(&mockSync.Sync{IsSyncing: false}),
-		WithChainService(chainService),
-		WithOperationNotifier(chainService.OperationNotifier()),
-		WithBlsToExecPool(blstoexec.NewPool()),
-	)
-	beaconDB := testingdb.SetupDB(t)
-	s.cfg.stateGen = stategen.New(beaconDB, doublylinkedtree.New())
-	s.cfg.beaconDB = beaconDB
-	s.initCaches()
-	st, _ := util.DeterministicGenesisStateCapella(t, 32)
-	s.cfg.chain = &mockChain.ChainService{
-		ValidatorsRoot: [32]byte{'A'},
-		Genesis:        time.Now().Add(-time.Second * time.Duration(params.BeaconConfig().SecondsPerSlot) * time.Duration(10)),
-		State:          st,
-	}
-
-	s.broadcastBLSBatch(s.ctx, &changes)
-	require.Equal(t, 200-128, len(changes))
-}

beacon-chain/sync/custody.go

@@ -106,6 +106,9 @@ func (s *Service) custodyGroupCount() (uint64, error) {
 // validatorsCustodyRequirements computes the custody requirements based on the
 // finalized state and the tracked validators.
 func (s *Service) validatorsCustodyRequirement() (uint64, error) {
+	if s.trackedValidatorsCache == nil {
+		return 0, nil
+	}
 	// Get the indices of the tracked validators.
 	indices := s.trackedValidatorsCache.Indices()
 

beacon-chain/sync/data_column_sidecars.go

@@ -0,0 +1,950 @@
+package sync
+
+import (
+	"bytes"
+	"context"
+	"slices"
+	"sync"
+	"time"
+
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/blockchain"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/core/peerdas"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filesystem"
+	prysmP2P "github.com/OffchainLabs/prysm/v6/beacon-chain/p2p"
+	p2ptypes "github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/types"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/verification"
+	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"
+	leakybucket "github.com/OffchainLabs/prysm/v6/container/leaky-bucket"
+	"github.com/OffchainLabs/prysm/v6/crypto/rand"
+	eth "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
+	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
+	goPeer "github.com/libp2p/go-libp2p/core/peer"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+)
+
+// DataColumnSidecarsParams stores the common parameters needed to
+// fetch data column sidecars from peers.
+type DataColumnSidecarsParams struct {
+	Ctx                     context.Context                     // Context
+	Tor                     blockchain.TemporalOracle           // Temporal oracle, useful to get the current slot
+	P2P                     prysmP2P.P2P                        // P2P network interface
+	RateLimiter             *leakybucket.Collector              // Rate limiter for outgoing requests
+	CtxMap                  ContextByteVersions                 // Context map, useful to know if a message is mapped to the correct fork
+	Storage                 filesystem.DataColumnStorageReader  // Data columns storage
+	NewVerifier             verification.NewDataColumnsVerifier // Data columns verifier to check to conformity of incoming data column sidecars
+	DownscorePeerOnRPCFault bool                                // Downscore a peer if it commits an RPC fault. Not responding sidecars at all is considered as a fault.
+}
+
+// FetchDataColumnSidecars retrieves data column sidecars from storage and peers for the given
+// blocks and requested data column indices. It employs a multi-step strategy:
+//
+//  1. Direct retrieval: If all requested columns are available in storage, they are
+//     retrieved directly without reconstruction.
+//  2. Reconstruction-based retrieval: If some requested columns are missing but sufficient
+//     stored columns exist (at least the minimum required for reconstruction), the function
+//     reconstructs all columns and extracts the requested indices.
+//  3. Peer retrieval: If storage and reconstruction fail, missing columns are requested
+//     from connected peers that are expected to custody the required data.
+//
+// The function returns a map of block roots to their corresponding verified read-only data
+// columns. It returns an error if data column storage is unavailable, if storage/reconstruction
+// operations fail unexpectedly, or if not all requested columns could be retrieved from peers.
+func FetchDataColumnSidecars(
+	params DataColumnSidecarsParams,
+	roBlocks []blocks.ROBlock,
+	indicesMap map[uint64]bool,
+) (map[[fieldparams.RootLength]byte][]blocks.VerifiedRODataColumn, error) {
+	if len(roBlocks) == 0 || len(indicesMap) == 0 {
+		return nil, nil
+	}
+
+	indices := sortedSliceFromMap(indicesMap)
+	slotsWithCommitments := make(map[primitives.Slot]bool)
+	missingIndicesByRoot := make(map[[fieldparams.RootLength]byte]map[uint64]bool)
+	indicesByRootStored := make(map[[fieldparams.RootLength]byte]map[uint64]bool)
+	result := make(map[[fieldparams.RootLength]byte][]blocks.VerifiedRODataColumn)
+
+	for _, roBlock := range roBlocks {
+		// Filter out blocks without commitments.
+		block := roBlock.Block()
+		commitments, err := block.Body().BlobKzgCommitments()
+		if err != nil {
+			return nil, errors.Wrapf(err, "get blob kzg commitments for block root %#x", roBlock.Root())
+		}
+		if len(commitments) == 0 {
+			continue
+		}
+
+		slotsWithCommitments[block.Slot()] = true
+		root := roBlock.Root()
+
+		// Step 1: Get the requested sidecars for this root if available in storage
+		requestedColumns, err := tryGetStoredColumns(params.Storage, root, indices)
+		if err != nil {
+			return nil, errors.Wrapf(err, "try get direct columns for root %#x", root)
+		}
+		if requestedColumns != nil {
+			result[root] = requestedColumns
+			continue
+		}
+
+		// Step 2: If step 1 failed, reconstruct the requested sidecars from what is available in storage
+		requestedColumns, err = tryGetReconstructedColumns(params.Storage, root, indices)
+		if err != nil {
+			return nil, errors.Wrapf(err, "try get reconstructed columns for root %#x", root)
+		}
+		if requestedColumns != nil {
+			result[root] = requestedColumns
+			continue
+		}
+
+		// Step 3a: If steps 1 and 2 failed, keep track of the sidecars that need to be queried from peers
+		//          and those that are already stored.
+		indicesToQueryMap, indicesStoredMap := categorizeIndices(params.Storage, root, indices)
+
+		if len(indicesToQueryMap) > 0 {
+			missingIndicesByRoot[root] = indicesToQueryMap
+		}
+		if len(indicesStoredMap) > 0 {
+			indicesByRootStored[root] = indicesStoredMap
+		}
+	}
+
+	// Early return if no sidecars need to be queried from peers.
+	if len(missingIndicesByRoot) == 0 {
+		return result, nil
+	}
+
+	// Step 3b: Request missing sidecars from peers.
+	start, count := time.Now(), computeTotalCount(missingIndicesByRoot)
+	fromPeersResult, err := tryRequestingColumnsFromPeers(params, roBlocks, slotsWithCommitments, missingIndicesByRoot)
+	if err != nil {
+		return nil, errors.Wrap(err, "request from peers")
+	}
+
+	log.WithFields(logrus.Fields{"duration": time.Since(start), "count": count}).Debug("Requested data column sidecars from peers")
+
+	// Step 3c: If needed, try to reconstruct missing sidecars from storage and fetched data.
+	fromReconstructionResult, err := tryReconstructFromStorageAndPeers(params.Storage, fromPeersResult, indicesMap, missingIndicesByRoot)
+	if err != nil {
+		return nil, errors.Wrap(err, "reconstruct from storage and peers")
+	}
+
+	for root, verifiedSidecars := range fromReconstructionResult {
+		result[root] = verifiedSidecars
+	}
+
+	for root := range fromPeersResult {
+		if _, ok := fromReconstructionResult[root]; ok {
+			// We already have what we need from peers + reconstruction
+			continue
+		}
+
+		result[root] = append(result[root], fromPeersResult[root]...)
+
+		storedIndices := indicesByRootStored[root]
+		if len(storedIndices) == 0 {
+			continue
+		}
+
+		storedColumns, err := tryGetStoredColumns(params.Storage, root, sortedSliceFromMap(storedIndices))
+		if err != nil {
+			return nil, errors.Wrapf(err, "try get direct columns for root %#x", root)
+		}
+
+		result[root] = append(result[root], storedColumns...)
+	}
+
+	return result, nil
+}
+
+// tryGetStoredColumns attempts to retrieve all requested data column sidecars directly from storage
+// if they are all available. Returns the sidecars if successful, and nil if at least one
+// requested sidecar is not available in the storage.
+func tryGetStoredColumns(storage filesystem.DataColumnStorageReader, blockRoot [fieldparams.RootLength]byte, indices []uint64) ([]blocks.VerifiedRODataColumn, error) {
+	// Check if all requested indices are present in cache
+	storedIndices := storage.Summary(blockRoot).Stored()
+	allRequestedPresent := true
+	for _, requestedIndex := range indices {
+		if !storedIndices[requestedIndex] {
+			allRequestedPresent = false
+			break
+		}
+	}
+
+	if !allRequestedPresent {
+		return nil, nil
+	}
+
+	// All requested data is present, retrieve directly from DB
+	requestedColumns, err := storage.Get(blockRoot, indices)
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed to get data columns for block root %#x", blockRoot)
+	}
+
+	return requestedColumns, nil
+}
+
+// tryGetReconstructedColumns attempts to retrieve columns using reconstruction
+// if sufficient columns are available. Returns the columns if successful, nil and nil if insufficient columns,
+// or nil and error if an error occurs.
+func tryGetReconstructedColumns(storage filesystem.DataColumnStorageReader, blockRoot [fieldparams.RootLength]byte, indices []uint64) ([]blocks.VerifiedRODataColumn, error) {
+	// Check if we have enough columns for reconstruction
+	summary := storage.Summary(blockRoot)
+	if summary.Count() < peerdas.MinimumColumnCountToReconstruct() {
+		return nil, nil
+	}
+
+	// Retrieve all stored columns for reconstruction
+	allStoredColumns, err := storage.Get(blockRoot, nil)
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed to get all stored columns for reconstruction for block root %#x", blockRoot)
+	}
+
+	// Attempt reconstruction
+	reconstructedColumns, err := peerdas.ReconstructDataColumnSidecars(allStoredColumns)
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed to reconstruct data columns for block root %#x", blockRoot)
+	}
+
+	// Health check: ensure we have the expected number of columns
+	numberOfColumns := params.BeaconConfig().NumberOfColumns
+	if uint64(len(reconstructedColumns)) != numberOfColumns {
+		return nil, errors.Errorf("reconstructed %d columns but expected %d for block root %#x", len(reconstructedColumns), numberOfColumns, blockRoot)
+	}
+
+	// Extract only the requested indices from reconstructed data using direct indexing
+	requestedColumns := make([]blocks.VerifiedRODataColumn, 0, len(indices))
+	for _, requestedIndex := range indices {
+		if requestedIndex >= numberOfColumns {
+			return nil, errors.Errorf("requested column index %d exceeds maximum %d for block root %#x", requestedIndex, numberOfColumns-1, blockRoot)
+		}
+		requestedColumns = append(requestedColumns, reconstructedColumns[requestedIndex])
+	}
+
+	return requestedColumns, nil
+}
+
+// categorizeIndices separates indices into those that need to be queried from peers
+// and those that are already stored.
+func categorizeIndices(storage filesystem.DataColumnStorageReader, blockRoot [fieldparams.RootLength]byte, indices []uint64) (map[uint64]bool, map[uint64]bool) {
+	indicesToQuery := make(map[uint64]bool, len(indices))
+	indicesStored := make(map[uint64]bool, len(indices))
+
+	allStoredIndices := storage.Summary(blockRoot).Stored()
+	for _, index := range indices {
+		if allStoredIndices[index] {
+			indicesStored[index] = true
+			continue
+		}
+		indicesToQuery[index] = true
+	}
+
+	return indicesToQuery, indicesStored
+}
+
+// tryRequestingColumnsFromPeers attempts to request missing data column sidecars from connected peers.
+// It explores the connected peers to find those that are expected to custody the requested columns
+// and returns only when all requested columns are either retrieved or have been tried to be retrieved
+// by all possible peers.
+// WARNING: This function alters `missingIndicesByRoot` by removing successfully retrieved columns.
+// After running this function, the user can check the content of the (modified) `missingIndicesByRoot` map
+// to check if some sidecars are still missing.
+func tryRequestingColumnsFromPeers(
+	p DataColumnSidecarsParams,
+	roBlocks []blocks.ROBlock,
+	slotsWithCommitments map[primitives.Slot]bool,
+	missingIndicesByRoot map[[fieldparams.RootLength]byte]map[uint64]bool,
+) (map[[fieldparams.RootLength]byte][]blocks.VerifiedRODataColumn, error) {
+	// Create a new random source for peer selection.
+	randomSource := rand.NewGenerator()
+
+	// Compute slots by block root.
+	slotByRoot := computeSlotByBlockRoot(roBlocks)
+
+	// Determine all sidecars each peers are expected to custody.
+	connectedPeersSlice := p.P2P.Peers().Connected()
+	connectedPeers := make(map[goPeer.ID]bool, len(connectedPeersSlice))
+	for _, peer := range connectedPeersSlice {
+		connectedPeers[peer] = true
+	}
+
+	indicesByRootByPeer, err := computeIndicesByRootByPeer(p.P2P, slotByRoot, missingIndicesByRoot, connectedPeers)
+	if err != nil {
+		return nil, errors.Wrap(err, "explore peers")
+	}
+
+	verifiedColumnsByRoot := make(map[[fieldparams.RootLength]byte][]blocks.VerifiedRODataColumn)
+	for len(missingIndicesByRoot) > 0 && len(indicesByRootByPeer) > 0 {
+		// Select peers to query the missing sidecars from.
+		indicesByRootByPeerToQuery, err := selectPeers(p, randomSource, len(missingIndicesByRoot), indicesByRootByPeer)
+		if err != nil {
+			return nil, errors.Wrap(err, "select peers")
+		}
+
+		// Remove selected peers from the maps.
+		for peer := range indicesByRootByPeerToQuery {
+			delete(connectedPeers, peer)
+		}
+
+		// Fetch the sidecars from the chosen peers.
+		roDataColumnsByPeer := fetchDataColumnSidecarsFromPeers(p, slotByRoot, slotsWithCommitments, indicesByRootByPeerToQuery)
+
+		// Verify the received data column sidecars.
+		verifiedRoDataColumnSidecars, err := verifyDataColumnSidecarsByPeer(p.P2P, p.NewVerifier, roDataColumnsByPeer)
+		if err != nil {
+			return nil, errors.Wrap(err, "verify data columns sidecars by peer")
+		}
+
+		// Remove the verified sidecars from the missing indices map and compute the new verified columns by root.
+		localVerifiedColumnsByRoot := updateResults(verifiedRoDataColumnSidecars, missingIndicesByRoot)
+		for root, verifiedRoDataColumns := range localVerifiedColumnsByRoot {
+			verifiedColumnsByRoot[root] = append(verifiedColumnsByRoot[root], verifiedRoDataColumns...)
+		}
+
+		// Compute indices by root by peers with the updated missing indices and connected peers.
+		indicesByRootByPeer, err = computeIndicesByRootByPeer(p.P2P, slotByRoot, missingIndicesByRoot, connectedPeers)
+		if err != nil {
+			return nil, errors.Wrap(err, "explore peers")
+		}
+	}
+
+	return verifiedColumnsByRoot, nil
+}
+
+// tryReconstructFromStorageAndPeers attempts to reconstruct missing data column sidecars
+// using the data available in the storage and the data fetched from peers.
+// If, for at least one root, the reconstruction is not possible, an error is returned.
+func tryReconstructFromStorageAndPeers(
+	storage filesystem.DataColumnStorageReader,
+	fromPeersByRoot map[[fieldparams.RootLength]byte][]blocks.VerifiedRODataColumn,
+	indices map[uint64]bool,
+	missingIndicesByRoot map[[fieldparams.RootLength]byte]map[uint64]bool,
+) (map[[fieldparams.RootLength]byte][]blocks.VerifiedRODataColumn, error) {
+	if len(missingIndicesByRoot) == 0 {
+		// Nothing to do, return early.
+		return nil, nil
+	}
+
+	minimumColumnsCountToReconstruct := peerdas.MinimumColumnCountToReconstruct()
+
+	start := time.Now()
+	result := make(map[[fieldparams.RootLength]byte][]blocks.VerifiedRODataColumn, len(missingIndicesByRoot))
+	for root := range missingIndicesByRoot {
+		// Check if a reconstruction is possible based on what we have from the store and fetched from peers.
+		summary := storage.Summary(root)
+		storedCount := summary.Count()
+		fetchedCount := uint64(len(fromPeersByRoot[root]))
+
+		if storedCount+fetchedCount < minimumColumnsCountToReconstruct {
+			return nil, errors.Errorf("cannot reconstruct all needed columns for root %#x. stored: %d, fetched: %d, minimum: %d", root, storedCount, fetchedCount, minimumColumnsCountToReconstruct)
+		}
+
+		// Load all we have in the store.
+		storedSidecars, err := storage.Get(root, nil)
+		if err != nil {
+			return nil, errors.Wrapf(err, "failed to get stored sidecars for root %#x", root)
+		}
+
+		sidecars := make([]blocks.VerifiedRODataColumn, 0, storedCount+fetchedCount)
+		sidecars = append(sidecars, storedSidecars...)
+		sidecars = append(sidecars, fromPeersByRoot[root]...)
+
+		// Attempt reconstruction.
+		reconstructedSidecars, err := peerdas.ReconstructDataColumnSidecars(sidecars)
+		if err != nil {
+			return nil, errors.Wrapf(err, "failed to reconstruct data columns for root %#x", root)
+		}
+
+		// Select only sidecars we need.
+		for _, sidecar := range reconstructedSidecars {
+			if indices[sidecar.Index] {
+				result[root] = append(result[root], sidecar)
+			}
+		}
+	}
+
+	log.WithFields(logrus.Fields{
+		"rootCount": len(missingIndicesByRoot),
+		"elapsed":   time.Since(start),
+	}).Debug("Reconstructed from storage and peers")
+
+	return result, nil
+}
+
+// selectPeers selects peers to query the sidecars.
+// It begins by randomly selecting a peer in `origIndicesByRootByPeer` that has enough bandwidth,
+// and assigns to it all its available sidecars. Then, it randomly select an other peer, until
+// all sidecars in `missingIndicesByRoot` are covered.
+func selectPeers(
+	p DataColumnSidecarsParams,
+	randomSource *rand.Rand,
+	count int,
+	origIndicesByRootByPeer map[goPeer.ID]map[[fieldparams.RootLength]byte]map[uint64]bool,
+) (map[goPeer.ID]map[[fieldparams.RootLength]byte]map[uint64]bool, error) {
+	const randomPeerTimeout = 2 * time.Minute
+
+	// Select peers to query the missing sidecars from.
+	indicesByRootByPeer := copyIndicesByRootByPeer(origIndicesByRootByPeer)
+	internalIndicesByRootByPeer := copyIndicesByRootByPeer(indicesByRootByPeer)
+	indicesByRootByPeerToQuery := make(map[goPeer.ID]map[[fieldparams.RootLength]byte]map[uint64]bool)
+	for len(internalIndicesByRootByPeer) > 0 {
+		// Randomly select a peer with enough bandwidth.
+		peer, err := func() (goPeer.ID, error) {
+			ctx, cancel := context.WithTimeout(p.Ctx, randomPeerTimeout)
+			defer cancel()
+
+			peer, err := randomPeer(ctx, randomSource, p.RateLimiter, count, internalIndicesByRootByPeer)
+			if err != nil {
+				return "", errors.Wrap(err, "select random peer")
+			}
+
+			return peer, err
+		}()
+		if err != nil {
+			return nil, err
+		}
+
+		// Query all the sidecars that peer can offer us.
+		newIndicesByRoot, ok := internalIndicesByRootByPeer[peer]
+		if !ok {
+			return nil, errors.Errorf("peer %s not found in internal indices by root by peer map", peer)
+		}
+
+		indicesByRootByPeerToQuery[peer] = newIndicesByRoot
+
+		// Remove this peer from the maps to avoid re-selection.
+		delete(indicesByRootByPeer, peer)
+		delete(internalIndicesByRootByPeer, peer)
+
+		// Delete the corresponding sidecars from other peers in the internal map
+		// to avoid re-selection during this iteration.
+		for peer, indicesByRoot := range internalIndicesByRootByPeer {
+			for root, indices := range indicesByRoot {
+				newIndices := newIndicesByRoot[root]
+				for index := range newIndices {
+					delete(indices, index)
+				}
+				if len(indices) == 0 {
+					delete(indicesByRoot, root)
+				}
+			}
+			if len(indicesByRoot) == 0 {
+				delete(internalIndicesByRootByPeer, peer)
+			}
+		}
+	}
+
+	return indicesByRootByPeerToQuery, nil
+}
+
+// updateResults updates the missing indices and verified sidecars maps based on the newly verified sidecars.
+// WARNING: This function alters `missingIndicesByRoot` by removing verified sidecars.
+// After running this function, the user can check the content of the (modified) `missingIndicesByRoot` map
+// to check if some sidecars are still missing.
+func updateResults(
+	verifiedSidecars []blocks.VerifiedRODataColumn,
+	missingIndicesByRoot map[[fieldparams.RootLength]byte]map[uint64]bool,
+) map[[fieldparams.RootLength]byte][]blocks.VerifiedRODataColumn {
+	// Copy the original map to avoid modifying it directly.
+	verifiedSidecarsByRoot := make(map[[fieldparams.RootLength]byte][]blocks.VerifiedRODataColumn)
+	for _, verifiedSidecar := range verifiedSidecars {
+		blockRoot := verifiedSidecar.BlockRoot()
+		index := verifiedSidecar.Index
+
+		// Add to the result map grouped by block root
+		verifiedSidecarsByRoot[blockRoot] = append(verifiedSidecarsByRoot[blockRoot], verifiedSidecar)
+
+		if indices, ok := missingIndicesByRoot[blockRoot]; ok {
+			delete(indices, index)
+			if len(indices) == 0 {
+				delete(missingIndicesByRoot, blockRoot)
+			}
+		}
+	}
+
+	return verifiedSidecarsByRoot
+}
+
+// fetchDataColumnSidecarsFromPeers retrieves data column sidecars from peers.
+func fetchDataColumnSidecarsFromPeers(
+	params DataColumnSidecarsParams,
+	slotByRoot map[[fieldparams.RootLength]byte]primitives.Slot,
+	slotsWithCommitments map[primitives.Slot]bool,
+	indicesByRootByPeer map[goPeer.ID]map[[fieldparams.RootLength]byte]map[uint64]bool,
+) map[goPeer.ID][]blocks.RODataColumn {
+	var (
+		wg  sync.WaitGroup
+		mut sync.Mutex
+	)
+
+	roDataColumnsByPeer := make(map[goPeer.ID][]blocks.RODataColumn)
+	wg.Add(len(indicesByRootByPeer))
+	for peerID, indicesByRoot := range indicesByRootByPeer {
+		go func(peerID goPeer.ID, indicesByRoot map[[fieldparams.RootLength]byte]map[uint64]bool) {
+			defer wg.Done()
+
+			requestedCount := 0
+			for _, indices := range indicesByRoot {
+				requestedCount += len(indices)
+			}
+
+			log := log.WithFields(logrus.Fields{
+				"peerID":              peerID,
+				"agent":               agentString(peerID, params.P2P.Host()),
+				"blockCount":          len(indicesByRoot),
+				"totalRequestedCount": requestedCount,
+			})
+
+			roDataColumns, err := sendDataColumnSidecarsRequest(params, slotByRoot, slotsWithCommitments, peerID, indicesByRoot)
+			if err != nil {
+				log.WithError(err).Warning("Failed to send data column sidecars request")
+				return
+			}
+
+			mut.Lock()
+			defer mut.Unlock()
+			roDataColumnsByPeer[peerID] = roDataColumns
+		}(peerID, indicesByRoot)
+	}
+
+	wg.Wait()
+
+	return roDataColumnsByPeer
+}
+
+func sendDataColumnSidecarsRequest(
+	params DataColumnSidecarsParams,
+	slotByRoot map[[fieldparams.RootLength]byte]primitives.Slot,
+	slotsWithCommitments map[primitives.Slot]bool,
+	peerID goPeer.ID,
+	indicesByRoot map[[fieldparams.RootLength]byte]map[uint64]bool,
+) ([]blocks.RODataColumn, error) {
+	const batchSize = 32
+
+	rootCount := int64(len(indicesByRoot))
+	requestedSidecarsCount := 0
+	for _, indices := range indicesByRoot {
+		requestedSidecarsCount += len(indices)
+	}
+
+	log := log.WithFields(logrus.Fields{
+		"peerID":            peerID,
+		"agent":             agentString(peerID, params.P2P.Host()),
+		"requestedSidecars": requestedSidecarsCount,
+	})
+
+	// Try to build a by range byRangeRequest first.
+	byRangeRequests, err := buildByRangeRequests(slotByRoot, slotsWithCommitments, indicesByRoot, batchSize)
+	if err != nil {
+		return nil, errors.Wrap(err, "craft by range request")
+	}
+
+	// If we have a valid by range request, send it.
+	if len(byRangeRequests) > 0 {
+		count := 0
+		for _, indices := range indicesByRoot {
+			count += len(indices)
+		}
+
+		start := time.Now()
+		roDataColumns := make([]blocks.RODataColumn, 0, count)
+		for _, request := range byRangeRequests {
+			if params.RateLimiter != nil {
+				params.RateLimiter.Add(peerID.String(), rootCount)
+			}
+
+			localRoDataColumns, err := SendDataColumnSidecarsByRangeRequest(params, peerID, request)
+			if err != nil {
+				return nil, errors.Wrapf(err, "send data column sidecars by range request to peer %s", peerID)
+			}
+
+			roDataColumns = append(roDataColumns, localRoDataColumns...)
+		}
+
+		log.WithFields(logrus.Fields{
+			"respondedSidecars": len(roDataColumns),
+			"requests":          len(byRangeRequests),
+			"type":              "byRange",
+			"duration":          time.Since(start),
+		}).Debug("Received data column sidecars")
+
+		return roDataColumns, nil
+	}
+
+	// Build identifiers for the by root request.
+	byRootRequest := buildByRootRequest(indicesByRoot)
+
+	// Send the by root request.
+	start := time.Now()
+	if params.RateLimiter != nil {
+		params.RateLimiter.Add(peerID.String(), rootCount)
+	}
+	roDataColumns, err := SendDataColumnSidecarsByRootRequest(params, peerID, byRootRequest)
+	if err != nil {
+		return nil, errors.Wrapf(err, "send data column sidecars by root request to peer %s", peerID)
+	}
+
+	log.WithFields(logrus.Fields{
+		"respondedSidecars": len(roDataColumns),
+		"requests":          1,
+		"type":              "byRoot",
+		"duration":          time.Since(start),
+	}).Debug("Received data column sidecars")
+
+	return roDataColumns, nil
+}
+
+// buildByRangeRequests constructs a by range request from the given indices,
+// only if the indices are the same all blocks and if the blocks are contiguous.
+// (Missing blocks or blocks without commitments do count as contiguous)
+// If one of this condition is not met, returns nil.
+func buildByRangeRequests(
+	slotByRoot map[[fieldparams.RootLength]byte]primitives.Slot,
+	slotsWithCommitments map[primitives.Slot]bool,
+	indicesByRoot map[[fieldparams.RootLength]byte]map[uint64]bool,
+	batchSize uint64,
+) ([]*ethpb.DataColumnSidecarsByRangeRequest, error) {
+	if len(indicesByRoot) == 0 {
+		return nil, nil
+	}
+
+	var reference map[uint64]bool
+	slots := make([]primitives.Slot, 0, len(slotByRoot))
+	for root, indices := range indicesByRoot {
+		if reference == nil {
+			reference = indices
+		}
+
+		if !compareIndices(reference, indices) {
+			return nil, nil
+		}
+
+		slot, ok := slotByRoot[root]
+		if !ok {
+			return nil, errors.Errorf("slot not found for block root %#x", root)
+		}
+
+		slots = append(slots, slot)
+	}
+
+	slices.Sort(slots)
+
+	for i := 1; i < len(slots); i++ {
+		previous, current := slots[i-1], slots[i]
+		if current == previous+1 {
+			continue
+		}
+
+		for j := previous + 1; j < current; j++ {
+			if slotsWithCommitments[j] {
+				return nil, nil
+			}
+		}
+	}
+
+	columns := sortedSliceFromMap(reference)
+	startSlot, endSlot := slots[0], slots[len(slots)-1]
+	totalCount := uint64(endSlot - startSlot + 1)
+
+	requests := make([]*ethpb.DataColumnSidecarsByRangeRequest, 0, totalCount/batchSize)
+	for start := startSlot; start <= endSlot; start += primitives.Slot(batchSize) {
+		end := min(start+primitives.Slot(batchSize)-1, endSlot)
+		request := &ethpb.DataColumnSidecarsByRangeRequest{
+			StartSlot: start,
+			Count:     uint64(end - start + 1),
+			Columns:   columns,
+		}
+
+		requests = append(requests, request)
+	}
+
+	return requests, nil
+}
+
+// buildByRootRequest constructs a by root request from the given indices.
+func buildByRootRequest(indicesByRoot map[[fieldparams.RootLength]byte]map[uint64]bool) p2ptypes.DataColumnsByRootIdentifiers {
+	identifiers := make(p2ptypes.DataColumnsByRootIdentifiers, 0, len(indicesByRoot))
+	for root, indices := range indicesByRoot {
+		identifier := &eth.DataColumnsByRootIdentifier{
+			BlockRoot: root[:],
+			Columns:   sortedSliceFromMap(indices),
+		}
+		identifiers = append(identifiers, identifier)
+	}
+
+	// Sort identifiers to have a deterministic output.
+	slices.SortFunc(identifiers, func(left, right *eth.DataColumnsByRootIdentifier) int {
+		if cmp := bytes.Compare(left.BlockRoot, right.BlockRoot); cmp != 0 {
+			return cmp
+		}
+		return slices.Compare(left.Columns, right.Columns)
+	})
+
+	return identifiers
+}
+
+// verifyDataColumnSidecarsByPeer verifies the received data column sidecars.
+// If at least one sidecar from a peer is invalid, the peer is downscored and
+// all its sidecars are rejected. (Sidecars from other peers are still accepted.)
+func verifyDataColumnSidecarsByPeer(
+	p2p prysmP2P.P2P,
+	newVerifier verification.NewDataColumnsVerifier,
+	roDataColumnsByPeer map[goPeer.ID][]blocks.RODataColumn,
+) ([]blocks.VerifiedRODataColumn, error) {
+	// First optimistically verify all received data columns in a single batch.
+	count := 0
+	for _, columns := range roDataColumnsByPeer {
+		count += len(columns)
+	}
+
+	roDataColumnSidecars := make([]blocks.RODataColumn, 0, count)
+	for _, columns := range roDataColumnsByPeer {
+		roDataColumnSidecars = append(roDataColumnSidecars, columns...)
+	}
+
+	verifiedRoDataColumnSidecars, err := verifyByRootDataColumnSidecars(newVerifier, roDataColumnSidecars)
+	if err == nil {
+		// This is the happy path where all sidecars are verified.
+		return verifiedRoDataColumnSidecars, nil
+	}
+
+	// An error occurred during verification, which means that at least one sidecar is invalid.
+	// Reverify peer by peer to identify faulty peer(s), reject all its sidecars, and downscore it.
+	verifiedRoDataColumnSidecars = make([]blocks.VerifiedRODataColumn, 0, count)
+	for peer, columns := range roDataColumnsByPeer {
+		peerVerifiedRoDataColumnSidecars, err := verifyByRootDataColumnSidecars(newVerifier, columns)
+		if err != nil {
+			// This peer has invalid sidecars.
+			log := log.WithError(err).WithField("peerID", peer)
+			newScore := p2p.Peers().Scorers().BadResponsesScorer().Increment(peer)
+			log.Warning("Peer returned invalid data column sidecars")
+			log.WithFields(logrus.Fields{"reason": "invalidDataColumnSidecars", "newScore": newScore}).Debug("Downscore peer")
+		}
+
+		verifiedRoDataColumnSidecars = append(verifiedRoDataColumnSidecars, peerVerifiedRoDataColumnSidecars...)
+	}
+
+	return verifiedRoDataColumnSidecars, nil
+}
+
+// verifyByRootDataColumnSidecars verifies the provided read-only data columns against the
+// requirements for data column sidecars received via the by root request.
+func verifyByRootDataColumnSidecars(newVerifier verification.NewDataColumnsVerifier, roDataColumns []blocks.RODataColumn) ([]blocks.VerifiedRODataColumn, error) {
+	verifier := newVerifier(roDataColumns, verification.ByRootRequestDataColumnSidecarRequirements)
+
+	if err := verifier.ValidFields(); err != nil {
+		return nil, errors.Wrap(err, "valid fields")
+	}
+
+	if err := verifier.SidecarInclusionProven(); err != nil {
+		return nil, errors.Wrap(err, "sidecar inclusion proven")
+	}
+
+	if err := verifier.SidecarKzgProofVerified(); err != nil {
+		return nil, errors.Wrap(err, "sidecar KZG proof verified")
+	}
+
+	verifiedRoDataColumns, err := verifier.VerifiedRODataColumns()
+	if err != nil {
+		return nil, errors.Wrap(err, "verified RO data columns - should never happen")
+	}
+
+	return verifiedRoDataColumns, nil
+}
+
+// computeIndicesByRootByPeer returns a peers->root->indices map only for
+// root and indices given in `indicesByBlockRoot`. It also only selects peers
+// for a given root only if its head state is higher than the block slot.
+func computeIndicesByRootByPeer(
+	p2p prysmP2P.P2P,
+	slotByBlockRoot map[[fieldparams.RootLength]byte]primitives.Slot,
+	indicesByBlockRoot map[[fieldparams.RootLength]byte]map[uint64]bool,
+	peers map[goPeer.ID]bool,
+) (map[goPeer.ID]map[[fieldparams.RootLength]byte]map[uint64]bool, error) {
+	// First, compute custody columns for all peers
+	peersByIndex := make(map[uint64]map[goPeer.ID]bool)
+	headSlotByPeer := make(map[goPeer.ID]primitives.Slot)
+	for peer := range peers {
+		// Computes the custody columns for each peer
+		nodeID, err := prysmP2P.ConvertPeerIDToNodeID(peer)
+		if err != nil {
+			return nil, errors.Wrapf(err, "convert peer ID to node ID for peer %s", peer)
+		}
+
+		custodyGroupCount := p2p.CustodyGroupCountFromPeer(peer)
+
+		dasInfo, _, err := peerdas.Info(nodeID, custodyGroupCount)
+		if err != nil {
+			return nil, errors.Wrapf(err, "peerdas info for peer %s", peer)
+		}
+
+		for column := range dasInfo.CustodyColumns {
+			if _, exists := peersByIndex[column]; !exists {
+				peersByIndex[column] = make(map[goPeer.ID]bool)
+			}
+			peersByIndex[column][peer] = true
+		}
+
+		// Compute the head slot for each peer
+		peerChainState, err := p2p.Peers().ChainState(peer)
+		if err != nil {
+			return nil, errors.Wrapf(err, "get chain state for peer %s", peer)
+		}
+
+		if peerChainState == nil {
+			return nil, errors.Errorf("chain state is nil for peer %s", peer)
+		}
+
+		headSlotByPeer[peer] = peerChainState.HeadSlot
+	}
+
+	// For each block root and its indices, find suitable peers
+	indicesByRootByPeer := make(map[goPeer.ID]map[[fieldparams.RootLength]byte]map[uint64]bool)
+	for blockRoot, indices := range indicesByBlockRoot {
+		blockSlot, ok := slotByBlockRoot[blockRoot]
+		if !ok {
+			return nil, errors.Errorf("slot not found for block root %#x", blockRoot)
+		}
+
+		for index := range indices {
+			peers := peersByIndex[index]
+			for peer := range peers {
+				peerHeadSlot, ok := headSlotByPeer[peer]
+				if !ok {
+					return nil, errors.Errorf("head slot not found for peer %s", peer)
+				}
+
+				if peerHeadSlot < blockSlot {
+					continue
+				}
+
+				// Build peers->root->indices map
+				if _, exists := indicesByRootByPeer[peer]; !exists {
+					indicesByRootByPeer[peer] = make(map[[fieldparams.RootLength]byte]map[uint64]bool)
+				}
+				if _, exists := indicesByRootByPeer[peer][blockRoot]; !exists {
+					indicesByRootByPeer[peer][blockRoot] = make(map[uint64]bool)
+				}
+				indicesByRootByPeer[peer][blockRoot][index] = true
+			}
+		}
+	}
+
+	return indicesByRootByPeer, nil
+}
+
+// randomPeer selects a random peer. If no peers has enough bandwidth, it will wait and retry.
+// Returns the selected peer ID and any error.
+func randomPeer(
+	ctx context.Context,
+	randomSource *rand.Rand,
+	rateLimiter *leakybucket.Collector,
+	count int,
+	indicesByRootByPeer map[goPeer.ID]map[[fieldparams.RootLength]byte]map[uint64]bool,
+) (goPeer.ID, error) {
+	const waitPeriod = 5 * time.Second
+
+	peerCount := len(indicesByRootByPeer)
+	if peerCount == 0 {
+		return "", errors.New("no peers available")
+	}
+
+	for ctx.Err() == nil {
+		nonRateLimitedPeers := make([]goPeer.ID, 0, len(indicesByRootByPeer))
+		for peer := range indicesByRootByPeer {
+			if rateLimiter == nil || rateLimiter.Remaining(peer.String()) >= int64(count) {
+				nonRateLimitedPeers = append(nonRateLimitedPeers, peer)
+			}
+		}
+
+		slices.Sort(nonRateLimitedPeers)
+
+		if len(nonRateLimitedPeers) == 0 {
+			log.WithFields(logrus.Fields{
+				"peerCount": peerCount,
+				"delay":     waitPeriod,
+			}).Debug("Waiting for a peer with enough bandwidth for data column sidecars")
+			time.Sleep(waitPeriod)
+			continue
+		}
+
+		randomIndex := randomSource.Intn(len(nonRateLimitedPeers))
+		return nonRateLimitedPeers[randomIndex], nil
+	}
+
+	return "", ctx.Err()
+}
+
+// copyIndicesByRootByPeer creates a deep copy of the given nested map.
+// Returns a new map with the same structure and contents.
+func copyIndicesByRootByPeer(original map[goPeer.ID]map[[fieldparams.RootLength]byte]map[uint64]bool) map[goPeer.ID]map[[fieldparams.RootLength]byte]map[uint64]bool {
+	copied := make(map[goPeer.ID]map[[fieldparams.RootLength]byte]map[uint64]bool, len(original))
+	for peer, indicesByRoot := range original {
+		copied[peer] = copyIndicesByRoot(indicesByRoot)
+	}
+
+	return copied
+}
+
+// copyIndicesByRoot creates a deep copy of the given nested map.
+// Returns a new map with the same structure and contents.
+func copyIndicesByRoot(original map[[fieldparams.RootLength]byte]map[uint64]bool) map[[fieldparams.RootLength]byte]map[uint64]bool {
+	copied := make(map[[fieldparams.RootLength]byte]map[uint64]bool, len(original))
+	for root, indexMap := range original {
+		copied[root] = make(map[uint64]bool, len(indexMap))
+		for index, value := range indexMap {
+			copied[root][index] = value
+		}
+	}
+	return copied
+}
+
+// compareIndices compares two map[uint64]bool and returns true if they are equal.
+func compareIndices(left, right map[uint64]bool) bool {
+	if len(left) != len(right) {
+		return false
+	}
+
+	for key, leftValue := range left {
+		rightValue, exists := right[key]
+		if !exists || leftValue != rightValue {
+			return false
+		}
+	}
+
+	return true
+}
+
+// sortedSliceFromMap converts a map[uint64]bool to a sorted slice of keys.
+func sortedSliceFromMap(m map[uint64]bool) []uint64 {
+	result := make([]uint64, 0, len(m))
+	for k := range m {
+		result = append(result, k)
+	}
+
+	slices.Sort(result)
+	return result
+}
+
+// computeSlotByBlockRoot maps each block root to its corresponding slot.
+func computeSlotByBlockRoot(roBlocks []blocks.ROBlock) map[[fieldparams.RootLength]byte]primitives.Slot {
+	slotByBlockRoot := make(map[[fieldparams.RootLength]byte]primitives.Slot, len(roBlocks))
+	for _, roBlock := range roBlocks {
+		slotByBlockRoot[roBlock.Root()] = roBlock.Block().Slot()
+	}
+	return slotByBlockRoot
+}
+
+// computeTotalCount calculates the total count of indices across all roots.
+func computeTotalCount(input map[[fieldparams.RootLength]byte]map[uint64]bool) int {
+	totalCount := 0
+	for _, indices := range input {
+		totalCount += len(indices)
+	}
+	return totalCount
+}

beacon-chain/sync/data_column_sidecars_test.go

@@ -0,0 +1,998 @@
+package sync
+
+import (
+	"context"
+	"fmt"
+	"math/rand"
+	"testing"
+	"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/db/filesystem"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/peers"
+	testp2p "github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/testing"
+	p2ptypes "github.com/OffchainLabs/prysm/v6/beacon-chain/p2p/types"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/startup"
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/verification"
+	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"
+	leakybucket "github.com/OffchainLabs/prysm/v6/container/leaky-bucket"
+	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
+	"github.com/OffchainLabs/prysm/v6/testing/assert"
+	"github.com/OffchainLabs/prysm/v6/testing/require"
+	"github.com/OffchainLabs/prysm/v6/testing/util"
+	"github.com/libp2p/go-libp2p"
+	"github.com/libp2p/go-libp2p/core/crypto"
+	"github.com/libp2p/go-libp2p/core/network"
+	"github.com/libp2p/go-libp2p/core/peer"
+)
+
+func TestFetchDataColumnSidecars(t *testing.T) {
+	numberOfColumns := params.BeaconConfig().NumberOfColumns
+	// Slot 1: All needed sidecars are available in storage
+	// Slot 2: No commitment
+	// Slot 3: All sidecars are saved excepted the needed ones
+	// Slot 4: Some sidecars are in the storage, other have to be retrieved from peers.
+	// Slot 5: Some sidecars are in the storage, other have to be retrieved from peers but peers do not deliver all requested sidecars.
+
+	params.SetupTestConfigCleanup(t)
+	cfg := params.BeaconConfig().Copy()
+	cfg.FuluForkEpoch = 0
+	params.OverrideBeaconConfig(cfg)
+
+	// Start the trusted setup.
+	err := kzg.Start()
+	require.NoError(t, err)
+
+	storage := filesystem.NewEphemeralDataColumnStorage(t)
+
+	ctxMap, err := ContextByteVersionsForValRoot(params.BeaconConfig().GenesisValidatorsRoot)
+	require.NoError(t, err)
+
+	const blobCount = 3
+	indices := map[uint64]bool{31: true, 81: true, 106: true}
+
+	// Block 1
+	block1, _, verifiedSidecars1 := util.GenerateTestFuluBlockWithSidecars(t, blobCount, util.WithSlot(1))
+	root1 := block1.Root()
+
+	toStore1 := make([]blocks.VerifiedRODataColumn, 0, len(indices))
+	for index := range indices {
+		sidecar := verifiedSidecars1[index]
+		toStore1 = append(toStore1, sidecar)
+	}
+
+	err = storage.Save(toStore1)
+	require.NoError(t, err)
+
+	// Block 2
+	block2, _, _ := util.GenerateTestFuluBlockWithSidecars(t, 0, util.WithSlot(2))
+
+	// Block 3
+	block3, _, verifiedSidecars3 := util.GenerateTestFuluBlockWithSidecars(t, blobCount, util.WithSlot(3))
+	root3 := block3.Root()
+
+	toStore3 := make([]blocks.VerifiedRODataColumn, 0, numberOfColumns-uint64(len(indices)))
+	for i := range numberOfColumns {
+		if !indices[i] {
+			sidecar := verifiedSidecars3[i]
+			toStore3 = append(toStore3, sidecar)
+		}
+	}
+
+	err = storage.Save(toStore3)
+	require.NoError(t, err)
+
+	// Block 4
+	block4, _, verifiedSidecars4 := util.GenerateTestFuluBlockWithSidecars(t, blobCount, util.WithSlot(4))
+	root4 := block4.Root()
+	toStore4 := []blocks.VerifiedRODataColumn{verifiedSidecars4[106]}
+
+	err = storage.Save(toStore4)
+	require.NoError(t, err)
+
+	// Block 5
+	minimumColumnsCountToReconstruct := peerdas.MinimumColumnCountToReconstruct()
+	block5, _, verifiedSidecars5 := util.GenerateTestFuluBlockWithSidecars(t, blobCount, util.WithSlot(5))
+	root5 := block5.Root()
+
+	toStoreCount := minimumColumnsCountToReconstruct - 1
+	toStore5 := make([]blocks.VerifiedRODataColumn, 0, toStoreCount)
+
+	for i := uint64(0); uint64(len(toStore5)) < toStoreCount; i++ {
+		sidecar := verifiedSidecars5[minimumColumnsCountToReconstruct+i]
+		if sidecar.Index == 81 {
+			continue
+		}
+
+		toStore5 = append(toStore5, sidecar)
+	}
+
+	err = storage.Save(toStore5)
+	require.NoError(t, err)
+
+	// Custody columns with this private key and 4-cgc: 31, 81, 97, 105
+	privateKeyBytes := [32]byte{1}
+	privateKey, err := crypto.UnmarshalSecp256k1PrivateKey(privateKeyBytes[:])
+	require.NoError(t, err)
+
+	// Peers
+	protocol := fmt.Sprintf("%s/ssz_snappy", p2p.RPCDataColumnSidecarsByRangeTopicV1)
+
+	p2p, other := testp2p.NewTestP2P(t), testp2p.NewTestP2P(t, libp2p.Identity(privateKey))
+	p2p.Peers().SetConnectionState(other.PeerID(), peers.Connected)
+	p2p.Connect(other)
+
+	p2p.Peers().SetChainState(other.PeerID(), &ethpb.StatusV2{
+		HeadSlot: 5,
+	})
+
+	expectedRequest := &ethpb.DataColumnSidecarsByRangeRequest{
+		StartSlot: 4,
+		Count:     2,
+		Columns:   []uint64{31, 81},
+	}
+
+	clock := startup.NewClock(time.Now(), [fieldparams.RootLength]byte{})
+
+	gs := startup.NewClockSynchronizer()
+	err = gs.SetClock(startup.NewClock(time.Unix(4113849600, 0), [fieldparams.RootLength]byte{}))
+	require.NoError(t, err)
+
+	waiter := verification.NewInitializerWaiter(gs, nil, nil)
+	initializer, err := waiter.WaitForInitializer(t.Context())
+	require.NoError(t, err)
+
+	newDataColumnsVerifier := newDataColumnsVerifierFromInitializer(initializer)
+
+	other.SetStreamHandler(protocol, func(stream network.Stream) {
+		actualRequest := new(ethpb.DataColumnSidecarsByRangeRequest)
+		err := other.Encoding().DecodeWithMaxLength(stream, actualRequest)
+		assert.NoError(t, err)
+		assert.DeepEqual(t, expectedRequest, actualRequest)
+
+		err = WriteDataColumnSidecarChunk(stream, clock, other.Encoding(), verifiedSidecars4[31].DataColumnSidecar)
+		assert.NoError(t, err)
+
+		err = WriteDataColumnSidecarChunk(stream, clock, other.Encoding(), verifiedSidecars4[81].DataColumnSidecar)
+		assert.NoError(t, err)
+
+		err = WriteDataColumnSidecarChunk(stream, clock, other.Encoding(), verifiedSidecars5[81].DataColumnSidecar)
+		assert.NoError(t, err)
+
+		err = stream.CloseWrite()
+		assert.NoError(t, err)
+	})
+
+	params := DataColumnSidecarsParams{
+		Ctx:         t.Context(),
+		Tor:         clock,
+		P2P:         p2p,
+		RateLimiter: leakybucket.NewCollector(1., 10, time.Second, false /* deleteEmptyBuckets */),
+		CtxMap:      ctxMap,
+		Storage:     storage,
+		NewVerifier: newDataColumnsVerifier,
+	}
+
+	expected := map[[fieldparams.RootLength]byte][]blocks.VerifiedRODataColumn{
+		root1: {verifiedSidecars1[31], verifiedSidecars1[81], verifiedSidecars1[106]},
+		// no root2 (no commitments in this block)
+		root3: {verifiedSidecars3[31], verifiedSidecars3[81], verifiedSidecars3[106]},
+		root4: {verifiedSidecars4[31], verifiedSidecars4[81], verifiedSidecars4[106]},
+		root5: {verifiedSidecars5[31], verifiedSidecars5[81], verifiedSidecars5[106]},
+	}
+
+	blocks := []blocks.ROBlock{block1, block2, block3, block4, block5}
+	actual, err := FetchDataColumnSidecars(params, blocks, indices)
+	require.NoError(t, err)
+
+	require.Equal(t, len(expected), len(actual))
+	for root := range expected {
+		require.Equal(t, len(expected[root]), len(actual[root]))
+		for i := range expected[root] {
+			require.DeepSSZEqual(t, expected[root][i], actual[root][i])
+		}
+	}
+}
+
+func TestCategorizeIndices(t *testing.T) {
+	storage := filesystem.NewEphemeralDataColumnStorage(t)
+
+	_, verifiedRoSidecars := util.CreateTestVerifiedRoDataColumnSidecars(t, []util.DataColumnParam{
+		{Slot: 1, Index: 12, Column: [][]byte{{1}, {2}, {3}}},
+		{Slot: 1, Index: 14, Column: [][]byte{{1}, {2}, {3}}},
+	})
+
+	err := storage.Save(verifiedRoSidecars)
+	require.NoError(t, err)
+
+	expectedToQuery := map[uint64]bool{13: true}
+	expectedStored := map[uint64]bool{12: true, 14: true}
+
+	actualToQuery, actualStored := categorizeIndices(storage, verifiedRoSidecars[0].BlockRoot(), []uint64{12, 13, 14})
+
+	require.Equal(t, len(expectedToQuery), len(actualToQuery))
+	require.Equal(t, len(expectedStored), len(actualStored))
+
+	for index := range expectedToQuery {
+		require.Equal(t, true, actualToQuery[index])
+	}
+	for index := range expectedStored {
+		require.Equal(t, true, actualStored[index])
+	}
+}
+
+func TestSelectPeers(t *testing.T) {
+	const (
+		count = 3
+		seed  = 42
+	)
+
+	params := DataColumnSidecarsParams{
+		Ctx:         t.Context(),
+		RateLimiter: leakybucket.NewCollector(1., 10, time.Second, false /* deleteEmptyBuckets */),
+	}
+
+	randomSource := rand.New(rand.NewSource(seed))
+
+	indicesByRootByPeer := map[peer.ID]map[[fieldparams.RootLength]byte]map[uint64]bool{
+		"peer1": {
+			{1}: {12: true, 13: true},
+			{2}: {13: true, 14: true, 15: true},
+			{3}: {14: true, 15: true},
+		},
+		"peer2": {
+			{1}: {13: true, 14: true},
+			{2}: {13: true, 14: true, 15: true},
+			{3}: {14: true, 16: true},
+		},
+	}
+
+	expected := map[peer.ID]map[[fieldparams.RootLength]byte]map[uint64]bool{
+		"peer1": {
+			{1}: {12: true},
+			{3}: {15: true},
+		},
+		"peer2": {
+			{1}: {13: true, 14: true},
+			{2}: {13: true, 14: true, 15: true},
+			{3}: {14: true, 16: true},
+		},
+	}
+
+	actual, err := selectPeers(params, randomSource, count, indicesByRootByPeer)
+
+	require.NoError(t, err)
+	require.Equal(t, len(expected), len(actual))
+	for peerID := range expected {
+		require.Equal(t, len(expected[peerID]), len(actual[peerID]))
+		for root := range expected[peerID] {
+			require.Equal(t, len(expected[peerID][root]), len(actual[peerID][root]))
+			for indices := range expected[peerID][root] {
+				require.Equal(t, expected[peerID][root][indices], actual[peerID][root][indices])
+			}
+		}
+	}
+}
+
+func TestUpdateResults(t *testing.T) {
+	_, verifiedSidecars := util.CreateTestVerifiedRoDataColumnSidecars(t, []util.DataColumnParam{
+		{Slot: 1, Index: 12, Column: [][]byte{{1}, {2}, {3}}},
+		{Slot: 1, Index: 13, Column: [][]byte{{1}, {2}, {3}}},
+		{Slot: 2, Index: 13, Column: [][]byte{{1}, {2}, {3}}},
+		{Slot: 2, Index: 14, Column: [][]byte{{1}, {2}, {3}}},
+	})
+
+	missingIndicesByRoot := map[[fieldparams.RootLength]byte]map[uint64]bool{
+		verifiedSidecars[0].BlockRoot(): {12: true, 13: true},
+		verifiedSidecars[2].BlockRoot(): {13: true, 14: true, 15: true},
+	}
+
+	expectedMissingIndicesByRoot := map[[fieldparams.RootLength]byte]map[uint64]bool{
+		verifiedSidecars[2].BlockRoot(): {15: true},
+	}
+
+	expectedVerifiedSidecarsByRoot := map[[fieldparams.RootLength]byte][]blocks.VerifiedRODataColumn{
+		verifiedSidecars[0].BlockRoot(): {verifiedSidecars[0], verifiedSidecars[1]},
+		verifiedSidecars[2].BlockRoot(): {verifiedSidecars[2], verifiedSidecars[3]},
+	}
+
+	actualVerifiedSidecarsByRoot := updateResults(verifiedSidecars, missingIndicesByRoot)
+	require.DeepEqual(t, expectedMissingIndicesByRoot, missingIndicesByRoot)
+	require.DeepEqual(t, expectedVerifiedSidecarsByRoot, actualVerifiedSidecarsByRoot)
+}
+
+func TestFetchDataColumnSidecarsFromPeers(t *testing.T) {
+	const count = 4
+
+	params.SetupTestConfigCleanup(t)
+	cfg := params.BeaconConfig().Copy()
+	cfg.FuluForkEpoch = 0
+	params.OverrideBeaconConfig(cfg)
+
+	clock := startup.NewClock(time.Now(), [fieldparams.RootLength]byte{})
+	ctxMap, err := ContextByteVersionsForValRoot(params.BeaconConfig().GenesisValidatorsRoot)
+	require.NoError(t, err)
+
+	kzgCommitmentsInclusionProof := make([][]byte, 0, count)
+	for range count {
+		kzgCommitmentsInclusionProof = append(kzgCommitmentsInclusionProof, make([]byte, 32))
+	}
+
+	expectedResponseSidecarPb := &ethpb.DataColumnSidecar{
+		Index: 2,
+		SignedBlockHeader: &ethpb.SignedBeaconBlockHeader{
+			Header: &ethpb.BeaconBlockHeader{
+				Slot:       1,
+				ParentRoot: make([]byte, fieldparams.RootLength),
+				StateRoot:  make([]byte, fieldparams.RootLength),
+				BodyRoot:   make([]byte, fieldparams.RootLength),
+			},
+			Signature: make([]byte, fieldparams.BLSSignatureLength),
+		},
+		KzgCommitmentsInclusionProof: kzgCommitmentsInclusionProof,
+	}
+
+	expectedResponseSidecar, err := blocks.NewRODataColumn(expectedResponseSidecarPb)
+	require.NoError(t, err)
+
+	slotByRoot := map[[fieldparams.RootLength]byte]primitives.Slot{
+		{1}: 1,
+		{3}: 3,
+		{4}: 4,
+		{7}: 7,
+	}
+
+	slotsWithCommitments := map[primitives.Slot]bool{
+		1: true,
+		3: true,
+		4: true,
+		7: true,
+	}
+
+	expectedRequest := &ethpb.DataColumnSidecarsByRangeRequest{
+		StartSlot: 1,
+		Count:     7,
+		Columns:   []uint64{1, 2},
+	}
+
+	protocol := fmt.Sprintf("%s/ssz_snappy", p2p.RPCDataColumnSidecarsByRangeTopicV1)
+	p2p, other := testp2p.NewTestP2P(t), testp2p.NewTestP2P(t)
+	p2p.Connect(other)
+
+	other.SetStreamHandler(protocol, func(stream network.Stream) {
+		receivedRequest := new(ethpb.DataColumnSidecarsByRangeRequest)
+		err := other.Encoding().DecodeWithMaxLength(stream, receivedRequest)
+		assert.NoError(t, err)
+		assert.DeepEqual(t, expectedRequest, receivedRequest)
+
+		err = WriteDataColumnSidecarChunk(stream, clock, other.Encoding(), expectedResponseSidecarPb)
+		assert.NoError(t, err)
+
+		err = stream.CloseWrite()
+		assert.NoError(t, err)
+	})
+
+	indicesByRootByPeer := map[peer.ID]map[[fieldparams.RootLength]byte]map[uint64]bool{
+		other.PeerID(): {
+			{1}: {1: true, 2: true},
+			{3}: {1: true, 2: true},
+			{4}: {1: true, 2: true},
+			{7}: {1: true, 2: true},
+		},
+	}
+
+	params := DataColumnSidecarsParams{
+		Ctx:         t.Context(),
+		Tor:         clock,
+		P2P:         p2p,
+		CtxMap:      ctxMap,
+		RateLimiter: leakybucket.NewCollector(1., 1, time.Second, false /* deleteEmptyBuckets */),
+	}
+
+	expectedResponse := map[peer.ID][]blocks.RODataColumn{
+		other.PeerID(): {expectedResponseSidecar},
+	}
+
+	actualResponse := fetchDataColumnSidecarsFromPeers(params, slotByRoot, slotsWithCommitments, indicesByRootByPeer)
+	require.Equal(t, len(expectedResponse), len(actualResponse))
+
+	for peerID := range expectedResponse {
+		require.DeepSSZEqual(t, expectedResponse[peerID], actualResponse[peerID])
+	}
+}
+
+func TestSendDataColumnSidecarsRequest(t *testing.T) {
+	const count = 4
+
+	params.SetupTestConfigCleanup(t)
+	cfg := params.BeaconConfig().Copy()
+	cfg.FuluForkEpoch = 0
+	params.OverrideBeaconConfig(cfg)
+
+	kzgCommitmentsInclusionProof := make([][]byte, 0, count)
+	for range count {
+		kzgCommitmentsInclusionProof = append(kzgCommitmentsInclusionProof, make([]byte, 32))
+	}
+
+	expectedResponsePb := &ethpb.DataColumnSidecar{
+		Index: 2,
+		SignedBlockHeader: &ethpb.SignedBeaconBlockHeader{
+			Header: &ethpb.BeaconBlockHeader{
+				Slot:       1,
+				ParentRoot: make([]byte, fieldparams.RootLength),
+				StateRoot:  make([]byte, fieldparams.RootLength),
+				BodyRoot:   make([]byte, fieldparams.RootLength),
+			},
+			Signature: make([]byte, fieldparams.BLSSignatureLength),
+		},
+		KzgCommitmentsInclusionProof: kzgCommitmentsInclusionProof,
+	}
+
+	expectedResponse, err := blocks.NewRODataColumn(expectedResponsePb)
+	require.NoError(t, err)
+
+	clock := startup.NewClock(time.Now(), params.BeaconConfig().GenesisValidatorsRoot)
+	ctxMap, err := ContextByteVersionsForValRoot(params.BeaconConfig().GenesisValidatorsRoot)
+	require.NoError(t, err)
+
+	t.Run("contiguous", func(t *testing.T) {
+		indicesByRoot := map[[fieldparams.RootLength]byte]map[uint64]bool{
+			{1}: {1: true, 2: true},
+			{3}: {1: true, 2: true},
+			{4}: {1: true, 2: true},
+			{7}: {1: true, 2: true},
+		}
+
+		slotByRoot := map[[fieldparams.RootLength]byte]primitives.Slot{
+			{1}: 1,
+			{3}: 3,
+			{4}: 4,
+			{7}: 7,
+		}
+
+		slotsWithCommitments := map[primitives.Slot]bool{
+			1: true,
+			3: true,
+			4: true,
+			7: true,
+		}
+
+		expectedRequest := &ethpb.DataColumnSidecarsByRangeRequest{
+			StartSlot: 1,
+			Count:     7,
+			Columns:   []uint64{1, 2},
+		}
+
+		protocol := fmt.Sprintf("%s/ssz_snappy", p2p.RPCDataColumnSidecarsByRangeTopicV1)
+		p2p, other := testp2p.NewTestP2P(t), testp2p.NewTestP2P(t)
+		p2p.Connect(other)
+
+		other.SetStreamHandler(protocol, func(stream network.Stream) {
+			receivedRequest := new(ethpb.DataColumnSidecarsByRangeRequest)
+			err := other.Encoding().DecodeWithMaxLength(stream, receivedRequest)
+			assert.NoError(t, err)
+			assert.DeepEqual(t, expectedRequest, receivedRequest)
+
+			err = WriteDataColumnSidecarChunk(stream, clock, other.Encoding(), expectedResponsePb)
+			assert.NoError(t, err)
+
+			err = stream.CloseWrite()
+			assert.NoError(t, err)
+		})
+
+		params := DataColumnSidecarsParams{
+			Ctx:         t.Context(),
+			Tor:         clock,
+			P2P:         p2p,
+			CtxMap:      ctxMap,
+			RateLimiter: leakybucket.NewCollector(1., 1, time.Second, false /* deleteEmptyBuckets */),
+		}
+
+		actualResponse, err := sendDataColumnSidecarsRequest(params, slotByRoot, slotsWithCommitments, other.PeerID(), indicesByRoot)
+		require.NoError(t, err)
+		require.DeepEqual(t, expectedResponse, actualResponse[0])
+	})
+
+	t.Run("non contiguous", func(t *testing.T) {
+		indicesByRoot := map[[fieldparams.RootLength]byte]map[uint64]bool{
+			expectedResponse.BlockRoot(): {1: true, 2: true},
+			{4}:                          {1: true, 2: true},
+			{7}:                          {1: true, 2: true},
+		}
+
+		slotByRoot := map[[fieldparams.RootLength]byte]primitives.Slot{
+			expectedResponse.BlockRoot(): 1,
+			{4}:                          4,
+			{7}:                          7,
+		}
+
+		slotsWithCommitments := map[primitives.Slot]bool{
+			1: true,
+			3: true,
+			4: true,
+			7: true,
+		}
+
+		roots := [...][fieldparams.RootLength]byte{expectedResponse.BlockRoot(), {4}, {7}}
+
+		expectedRequest := &p2ptypes.DataColumnsByRootIdentifiers{
+			{
+				BlockRoot: roots[1][:],
+				Columns:   []uint64{1, 2},
+			},
+			{
+				BlockRoot: roots[2][:],
+				Columns:   []uint64{1, 2},
+			},
+			{
+				BlockRoot: roots[0][:],
+				Columns:   []uint64{1, 2},
+			},
+		}
+
+		protocol := fmt.Sprintf("%s/ssz_snappy", p2p.RPCDataColumnSidecarsByRootTopicV1)
+		p2p, other := testp2p.NewTestP2P(t), testp2p.NewTestP2P(t)
+		p2p.Connect(other)
+
+		other.SetStreamHandler(protocol, func(stream network.Stream) {
+			receivedRequest := new(p2ptypes.DataColumnsByRootIdentifiers)
+			err := other.Encoding().DecodeWithMaxLength(stream, receivedRequest)
+			assert.NoError(t, err)
+			assert.DeepSSZEqual(t, *expectedRequest, *receivedRequest)
+
+			err = WriteDataColumnSidecarChunk(stream, clock, other.Encoding(), expectedResponsePb)
+			assert.NoError(t, err)
+
+			err = stream.CloseWrite()
+			assert.NoError(t, err)
+		})
+
+		params := DataColumnSidecarsParams{
+			Ctx:         t.Context(),
+			Tor:         clock,
+			P2P:         p2p,
+			CtxMap:      ctxMap,
+			RateLimiter: leakybucket.NewCollector(1., 1, time.Second, false /* deleteEmptyBuckets */),
+		}
+
+		actualResponse, err := sendDataColumnSidecarsRequest(params, slotByRoot, slotsWithCommitments, other.PeerID(), indicesByRoot)
+		require.NoError(t, err)
+		require.DeepEqual(t, expectedResponse, actualResponse[0])
+	})
+}
+
+func TestBuildByRangeRequests(t *testing.T) {
+	const nullBatchSize = 0
+
+	t.Run("empty", func(t *testing.T) {
+		actual, err := buildByRangeRequests(nil, nil, nil, nullBatchSize)
+		require.NoError(t, err)
+
+		require.Equal(t, 0, len(actual))
+	})
+
+	t.Run("missing Root", func(t *testing.T) {
+		indicesByRoot := map[[fieldparams.RootLength]byte]map[uint64]bool{
+			{1}: {1: true, 2: true},
+		}
+
+		_, err := buildByRangeRequests(nil, nil, indicesByRoot, nullBatchSize)
+		require.NotNil(t, err)
+	})
+
+	t.Run("indices differ", func(t *testing.T) {
+		indicesByRoot := map[[fieldparams.RootLength]byte]map[uint64]bool{
+			{1}: {1: true, 2: true},
+			{2}: {1: true, 2: true},
+			{3}: {2: true, 3: true},
+		}
+
+		slotByRoot := map[[fieldparams.RootLength]byte]primitives.Slot{
+			{1}: 1,
+			{2}: 2,
+			{3}: 3,
+		}
+
+		actual, err := buildByRangeRequests(slotByRoot, nil, indicesByRoot, nullBatchSize)
+		require.NoError(t, err)
+		require.Equal(t, 0, len(actual))
+	})
+
+	t.Run("slots non contiguous", func(t *testing.T) {
+		indicesByRoot := map[[fieldparams.RootLength]byte]map[uint64]bool{
+			{1}: {1: true, 2: true},
+			{2}: {1: true, 2: true},
+		}
+
+		slotByRoot := map[[fieldparams.RootLength]byte]primitives.Slot{
+			{1}: 1,
+			{2}: 3,
+		}
+
+		slotsWithCommitments := map[primitives.Slot]bool{
+			1: true,
+			2: true,
+			3: true,
+		}
+
+		actual, err := buildByRangeRequests(slotByRoot, slotsWithCommitments, indicesByRoot, nullBatchSize)
+		require.NoError(t, err)
+		require.Equal(t, 0, len(actual))
+	})
+
+	t.Run("nominal", func(t *testing.T) {
+		const batchSize = 3
+
+		indicesByRoot := map[[fieldparams.RootLength]byte]map[uint64]bool{
+			{1}: {1: true, 2: true},
+			{3}: {1: true, 2: true},
+			{4}: {1: true, 2: true},
+			{7}: {1: true, 2: true},
+		}
+
+		slotByRoot := map[[fieldparams.RootLength]byte]primitives.Slot{
+			{1}: 1,
+			{3}: 3,
+			{4}: 4,
+			{7}: 7,
+		}
+
+		slotsWithCommitments := map[primitives.Slot]bool{
+			1: true,
+			3: true,
+			4: true,
+			7: true,
+		}
+
+		expected := []*ethpb.DataColumnSidecarsByRangeRequest{
+			{
+				StartSlot: 1,
+				Count:     3,
+				Columns:   []uint64{1, 2},
+			},
+			{
+				StartSlot: 4,
+				Count:     3,
+				Columns:   []uint64{1, 2},
+			},
+			{
+				StartSlot: 7,
+				Count:     1,
+				Columns:   []uint64{1, 2},
+			},
+		}
+
+		actual, err := buildByRangeRequests(slotByRoot, slotsWithCommitments, indicesByRoot, batchSize)
+		require.NoError(t, err)
+		require.DeepEqual(t, expected, actual)
+	})
+}
+
+func TestBuildByRootRequest(t *testing.T) {
+	root1 := [fieldparams.RootLength]byte{1}
+	root2 := [fieldparams.RootLength]byte{2}
+
+	input := map[[fieldparams.RootLength]byte]map[uint64]bool{
+		root1: {1: true, 2: true},
+		root2: {3: true},
+	}
+
+	expected := p2ptypes.DataColumnsByRootIdentifiers{
+		{
+			BlockRoot: root1[:],
+			Columns:   []uint64{1, 2},
+		},
+		{
+			BlockRoot: root2[:],
+			Columns:   []uint64{3},
+		},
+	}
+
+	actual := buildByRootRequest(input)
+	require.DeepSSZEqual(t, expected, actual)
+}
+
+func TestVerifyDataColumnSidecarsByPeer(t *testing.T) {
+	err := kzg.Start()
+	require.NoError(t, err)
+
+	t.Run("nominal", func(t *testing.T) {
+		const (
+			start, stop = 0, 15
+			blobCount   = 1
+		)
+
+		p2p := testp2p.NewTestP2P(t)
+
+		// Setup test data and expectations
+		_, roDataColumnSidecars, expected := util.GenerateTestFuluBlockWithSidecars(t, blobCount)
+
+		roDataColumnsByPeer := map[peer.ID][]blocks.RODataColumn{
+			"peer1": roDataColumnSidecars[start:5],
+			"peer2": roDataColumnSidecars[5:9],
+			"peer3": roDataColumnSidecars[9:stop],
+		}
+		gs := startup.NewClockSynchronizer()
+		err := gs.SetClock(startup.NewClock(time.Unix(4113849600, 0), [fieldparams.RootLength]byte{}))
+		require.NoError(t, err)
+
+		waiter := verification.NewInitializerWaiter(gs, nil, nil)
+		initializer, err := waiter.WaitForInitializer(t.Context())
+		require.NoError(t, err)
+
+		newDataColumnsVerifier := newDataColumnsVerifierFromInitializer(initializer)
+		actual, err := verifyDataColumnSidecarsByPeer(p2p, newDataColumnsVerifier, roDataColumnsByPeer)
+		require.NoError(t, err)
+
+		require.Equal(t, stop-start, len(actual))
+
+		for i := range actual {
+			actualSidecar := actual[i]
+			index := actualSidecar.Index
+			expectedSidecar := expected[index]
+			require.DeepEqual(t, expectedSidecar, actualSidecar)
+		}
+	})
+
+	t.Run("one rogue peer", func(t *testing.T) {
+		const (
+			start, middle, stop = 0, 5, 15
+			blobCount           = 1
+		)
+
+		p2p := testp2p.NewTestP2P(t)
+
+		// Setup test data and expectations
+		_, roDataColumnSidecars, expected := util.GenerateTestFuluBlockWithSidecars(t, blobCount)
+
+		// Modify one sidecar to ensure proof verification fails.
+		if roDataColumnSidecars[middle].KzgProofs[0][0] == 0 {
+			roDataColumnSidecars[middle].KzgProofs[0][0]++
+		} else {
+			roDataColumnSidecars[middle].KzgProofs[0][0]--
+		}
+
+		roDataColumnsByPeer := map[peer.ID][]blocks.RODataColumn{
+			"peer1": roDataColumnSidecars[start:middle],
+			"peer2": roDataColumnSidecars[5:middle],
+			"peer3": roDataColumnSidecars[middle:stop],
+		}
+		gs := startup.NewClockSynchronizer()
+		err := gs.SetClock(startup.NewClock(time.Unix(4113849600, 0), [fieldparams.RootLength]byte{}))
+		require.NoError(t, err)
+
+		waiter := verification.NewInitializerWaiter(gs, nil, nil)
+		initializer, err := waiter.WaitForInitializer(t.Context())
+		require.NoError(t, err)
+
+		newDataColumnsVerifier := newDataColumnsVerifierFromInitializer(initializer)
+		actual, err := verifyDataColumnSidecarsByPeer(p2p, newDataColumnsVerifier, roDataColumnsByPeer)
+		require.NoError(t, err)
+
+		require.Equal(t, middle-start, len(actual))
+
+		for i := range actual {
+			actualSidecar := actual[i]
+			index := actualSidecar.Index
+			expectedSidecar := expected[index]
+			require.DeepEqual(t, expectedSidecar, actualSidecar)
+		}
+	})
+}
+
+func TestComputeIndicesByRootByPeer(t *testing.T) {
+	peerIdStrs := []string{
+		"16Uiu2HAm3k5Npu6EaYWxiEvzsdLseEkjVyoVhvbxWEuyqdBgBBbq", // Custodies 89, 94, 97 & 122
+		"16Uiu2HAmTwQPAwzTr6hTgBmKNecCfH6kP3Kbzxj36ZRyyQ46L6gf", // Custodies 1, 11, 37 & 86
+		"16Uiu2HAmMDB5uUePTpN7737m78ehePfWPtBL9qMGdH8kCygjzNA8", // Custodies 2, 37, 38 & 68
+		"16Uiu2HAmTAE5Vxf7Pgfk7eWpmCvVJdSba4C9xg4xkYuuvnVbgfFx", // Custodies 10, 29, 36 & 108
+	}
+
+	headSlotByPeer := map[string]primitives.Slot{
+		"16Uiu2HAm3k5Npu6EaYWxiEvzsdLseEkjVyoVhvbxWEuyqdBgBBbq": 89,
+		"16Uiu2HAmTwQPAwzTr6hTgBmKNecCfH6kP3Kbzxj36ZRyyQ46L6gf": 10,
+		"16Uiu2HAmMDB5uUePTpN7737m78ehePfWPtBL9qMGdH8kCygjzNA8": 12,
+		"16Uiu2HAmTAE5Vxf7Pgfk7eWpmCvVJdSba4C9xg4xkYuuvnVbgfFx": 9,
+	}
+
+	p2p := testp2p.NewTestP2P(t)
+	peers := p2p.Peers()
+
+	peerIDs := make([]peer.ID, 0, len(peerIdStrs))
+	for _, peerIdStr := range peerIdStrs {
+		peerID, err := peer.Decode(peerIdStr)
+		require.NoError(t, err)
+
+		peers.SetChainState(peerID, &ethpb.StatusV2{
+			HeadSlot: headSlotByPeer[peerIdStr],
+		})
+
+		peerIDs = append(peerIDs, peerID)
+	}
+
+	slotByBlockRoot := map[[fieldparams.RootLength]byte]primitives.Slot{
+		[fieldparams.RootLength]byte{1}: 8,
+		[fieldparams.RootLength]byte{2}: 10,
+		[fieldparams.RootLength]byte{3}: 9,
+		[fieldparams.RootLength]byte{4}: 50,
+	}
+
+	indicesByBlockRoot := map[[fieldparams.RootLength]byte]map[uint64]bool{
+		[fieldparams.RootLength]byte{1}: {3: true, 4: true, 5: true},
+		[fieldparams.RootLength]byte{2}: {1: true, 10: true, 37: true, 80: true},
+		[fieldparams.RootLength]byte{3}: {10: true, 38: true, 39: true, 40: true},
+		[fieldparams.RootLength]byte{4}: {89: true, 108: true, 122: true},
+	}
+
+	expected := map[peer.ID]map[[fieldparams.RootLength]byte]map[uint64]bool{
+		peerIDs[0]: {
+			[fieldparams.RootLength]byte{4}: {89: true, 122: true},
+		},
+		peerIDs[1]: {
+			[fieldparams.RootLength]byte{2}: {1: true, 37: true},
+		},
+		peerIDs[2]: {
+			[fieldparams.RootLength]byte{2}: {37: true},
+			[fieldparams.RootLength]byte{3}: {38: true},
+		},
+		peerIDs[3]: {
+			[fieldparams.RootLength]byte{3}: {10: true},
+		},
+	}
+
+	peerIDsMap := make(map[peer.ID]bool, len(peerIDs))
+	for _, id := range peerIDs {
+		peerIDsMap[id] = true
+	}
+
+	actual, err := computeIndicesByRootByPeer(p2p, slotByBlockRoot, indicesByBlockRoot, peerIDsMap)
+	require.NoError(t, err)
+	require.Equal(t, len(expected), len(actual))
+
+	for peer, indicesByRoot := range expected {
+		require.Equal(t, len(indicesByRoot), len(actual[peer]))
+		for root, indices := range indicesByRoot {
+			require.Equal(t, len(indices), len(actual[peer][root]))
+			for index := range indices {
+				require.Equal(t, actual[peer][root][index], true)
+			}
+		}
+	}
+}
+
+func TestRandomPeer(t *testing.T) {
+	// Fixed seed.
+	const seed = 43
+	randomSource := rand.New(rand.NewSource(seed))
+
+	t.Run("no peers", func(t *testing.T) {
+		pid, err := randomPeer(t.Context(), randomSource, leakybucket.NewCollector(4, 8, time.Second, false /* deleteEmptyBuckets */), 1, nil)
+		require.NotNil(t, err)
+		require.Equal(t, peer.ID(""), pid)
+	})
+
+	t.Run("context cancelled", func(t *testing.T) {
+		ctx, cancel := context.WithCancel(t.Context())
+		cancel()
+
+		indicesByRootByPeer := map[peer.ID]map[[fieldparams.RootLength]byte]map[uint64]bool{peer.ID("peer1"): {}}
+		pid, err := randomPeer(ctx, randomSource, leakybucket.NewCollector(4, 8, time.Second, false /* deleteEmptyBuckets */), 1, indicesByRootByPeer)
+		require.NotNil(t, err)
+		require.Equal(t, peer.ID(""), pid)
+	})
+
+	t.Run("nominal", func(t *testing.T) {
+		const count = 1
+		collector := leakybucket.NewCollector(4, 8, time.Second, false /* deleteEmptyBuckets */)
+		peer1, peer2, peer3 := peer.ID("peer1"), peer.ID("peer2"), peer.ID("peer3")
+
+		indicesByRootByPeer := map[peer.ID]map[[fieldparams.RootLength]byte]map[uint64]bool{
+			peer1: {},
+			peer2: {},
+			peer3: {},
+		}
+
+		pid, err := randomPeer(t.Context(), randomSource, collector, count, indicesByRootByPeer)
+		require.NoError(t, err)
+		require.Equal(t, peer1, pid)
+
+		pid, err = randomPeer(t.Context(), randomSource, collector, count, indicesByRootByPeer)
+		require.NoError(t, err)
+		require.Equal(t, peer2, pid)
+	})
+}
+
+func TestCopyIndicesByRootByPeer(t *testing.T) {
+	original := map[peer.ID]map[[fieldparams.RootLength]byte]map[uint64]bool{
+		peer.ID("peer1"): {
+			[fieldparams.RootLength]byte{1}: {1: true, 3: true},
+			[fieldparams.RootLength]byte{2}: {2: true},
+		},
+		peer.ID("peer2"): {
+			[fieldparams.RootLength]byte{1}: {1: true},
+		},
+	}
+
+	copied := copyIndicesByRootByPeer(original)
+
+	require.Equal(t, len(original), len(copied))
+	for peer, indicesByRoot := range original {
+		require.Equal(t, len(indicesByRoot), len(copied[peer]))
+		for root, indices := range indicesByRoot {
+			require.Equal(t, len(indices), len(copied[peer][root]))
+			for index := range indices {
+				require.Equal(t, copied[peer][root][index], true)
+			}
+		}
+	}
+}
+
+func TestCompareIndices(t *testing.T) {
+	left := map[uint64]bool{3: true, 5: true, 7: true}
+	right := map[uint64]bool{5: true}
+	require.Equal(t, false, compareIndices(left, right))
+
+	left = map[uint64]bool{3: true, 5: true, 7: true}
+	right = map[uint64]bool{3: true, 6: true, 7: true}
+	require.Equal(t, false, compareIndices(left, right))
+
+	left = map[uint64]bool{3: true, 5: true, 7: true}
+	right = map[uint64]bool{5: true, 7: true, 3: true}
+	require.Equal(t, true, compareIndices(left, right))
+}
+
+func TestSlortedSliceFromMap(t *testing.T) {
+	input := map[uint64]bool{54: true, 23: true, 35: true}
+	expected := []uint64{23, 35, 54}
+	actual := sortedSliceFromMap(input)
+	require.DeepEqual(t, expected, actual)
+}
+
+func TestComputeSlotByBlockRoot(t *testing.T) {
+	const (
+		count      = 3
+		multiplier = 10
+	)
+
+	roBlocks := make([]blocks.ROBlock, 0, count)
+	for i := range count {
+		signedBlock := util.NewBeaconBlock()
+		signedBlock.Block.Slot = primitives.Slot(i).Mul(multiplier)
+		roSignedBlock, err := blocks.NewSignedBeaconBlock(signedBlock)
+		require.NoError(t, err)
+
+		roBlock, err := blocks.NewROBlockWithRoot(roSignedBlock, [fieldparams.RootLength]byte{byte(i)})
+		require.NoError(t, err)
+
+		roBlocks = append(roBlocks, roBlock)
+	}
+
+	expected := map[[fieldparams.RootLength]byte]primitives.Slot{
+		[fieldparams.RootLength]byte{0}: primitives.Slot(0),
+		[fieldparams.RootLength]byte{1}: primitives.Slot(10),
+		[fieldparams.RootLength]byte{2}: primitives.Slot(20),
+	}
+
+	actual := computeSlotByBlockRoot(roBlocks)
+
+	require.Equal(t, len(expected), len(actual))
+	for k, v := range expected {
+		require.Equal(t, v, actual[k])
+	}
+}
+
+func TestComputeTotalCount(t *testing.T) {
+	input := map[[fieldparams.RootLength]byte]map[uint64]bool{
+		[fieldparams.RootLength]byte{1}: {1: true, 3: true},
+		[fieldparams.RootLength]byte{2}: {2: true},
+	}
+
+	const expected = 3
+	actual := computeTotalCount(input)
+	require.Equal(t, expected, actual)
+}

beacon-chain/sync/fork_watcher.go

@@ -12,6 +12,7 @@ import (
 // Is a background routine that observes for new incoming forks. Depending on the epoch
 // it will be in charge of subscribing/unsubscribing the relevant topics at the fork boundaries.
 func (s *Service) forkWatcher() {
+	<-s.initialSyncComplete
 	slotTicker := slots.NewSlotTicker(s.cfg.clock.GenesisTime(), params.BeaconConfig().SecondsPerSlot)
 	for {
 		select {
@@ -28,9 +29,6 @@ func (s *Service) forkWatcher() {
 				log.WithError(err).Error("Unable to check for fork in the previous epoch")
 				continue
 			}
-			// Broadcast BLS changes at the Capella fork boundary
-			s.broadcastBLSChanges(currSlot)
-
 		case <-s.ctx.Done():
 			log.Debug("Context closed, exiting goroutine")
 			slotTicker.Done()