PeerDAS: Implement DAS (#15367)

* PeerDAS: Implement DAS

* Fix Terence's comment.

* Fix Terence comment.

* Fix Terence's comment.

* Fix James' comment.

* Fix James' comment.

* Rename some variable/files with blobs.

* Fix James' comment.

* Fix James' comment.

* Fix James' comment.

beacon-chain/das/BUILD.bazel

@@ -3,22 +3,27 @@ load("@prysm//tools/go:def.bzl", "go_library", "go_test")
 go_library(
     name = "go_default_library",
     srcs = [
-        "availability.go",
-        "cache.go",
+        "availability_blobs.go",
+        "availability_columns.go",
+        "blob_cache.go",
+        "data_column_cache.go",
         "iface.go",
         "mock.go",
     ],
     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",
         "//config/params:go_default_library",
         "//consensus-types/blocks:go_default_library",
         "//consensus-types/primitives:go_default_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",
     ],
@@ -27,13 +32,18 @@ go_library(
 go_test(
     name = "go_default_test",
     srcs = [
-        "availability_test.go",
-        "cache_test.go",
+        "availability_blobs_test.go",
+        "availability_columns_test.go",
+        "blob_cache_test.go",
+        "data_column_cache_test.go",
     ],
     embed = [":go_default_library"],
     deps = [
+        "//beacon-chain/core/peerdas:go_default_library",
         "//beacon-chain/db/filesystem:go_default_library",
         "//beacon-chain/verification:go_default_library",
+        "//cmd/beacon-chain/flags:go_default_library",
+        "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
         "//consensus-types/blocks:go_default_library",
         "//consensus-types/primitives:go_default_library",
@@ -41,6 +51,7 @@ 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

@@ -20,16 +20,16 @@ var (
 	errMixedRoots = errors.New("BlobSidecars must all be for the same block")
 )
 
-// LazilyPersistentStore is an implementation of AvailabilityStore to be used when batch syncing.
+// LazilyPersistentStoreBlob is an implementation of AvailabilityStore to be used when batch syncing.
 // This implementation will hold any blobs 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 LazilyPersistentStore struct {
+type LazilyPersistentStoreBlob struct {
 	store    *filesystem.BlobStorage
-	cache    *cache
+	cache    *blobCache
 	verifier BlobBatchVerifier
 }
 
-var _ AvailabilityStore = &LazilyPersistentStore{}
+var _ AvailabilityStore = &LazilyPersistentStoreBlob{}
 
 // BlobBatchVerifier enables LazyAvailabilityStore to manage the verification process
 // going from ROBlob->VerifiedROBlob, while avoiding the decision of which individual verifications
@@ -42,10 +42,10 @@ type BlobBatchVerifier interface {
 
 // NewLazilyPersistentStore creates a new LazilyPersistentStore. This constructor should always be used
 // when creating a LazilyPersistentStore because it needs to initialize the cache under the hood.
-func NewLazilyPersistentStore(store *filesystem.BlobStorage, verifier BlobBatchVerifier) *LazilyPersistentStore {
-	return &LazilyPersistentStore{
+func NewLazilyPersistentStore(store *filesystem.BlobStorage, verifier BlobBatchVerifier) *LazilyPersistentStoreBlob {
+	return &LazilyPersistentStoreBlob{
 		store:    store,
-		cache:    newCache(),
+		cache:    newBlobCache(),
 		verifier: verifier,
 	}
 }
@@ -53,25 +53,31 @@ 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 *LazilyPersistentStore) Persist(current primitives.Slot, sc ...blocks.ROBlob) error {
-	if len(sc) == 0 {
+func (s *LazilyPersistentStoreBlob) Persist(current primitives.Slot, sidecars ...blocks.ROSidecar) error {
+	if len(sidecars) == 0 {
 		return nil
 	}
-	if len(sc) > 1 {
-		first := sc[0].BlockRoot()
-		for i := 1; i < len(sc); i++ {
-			if first != sc[i].BlockRoot() {
+
+	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 sidecar.BlockRoot() != firstRoot {
 				return errMixedRoots
 			}
 		}
 	}
-	if !params.WithinDAPeriod(slots.ToEpoch(sc[0].Slot()), slots.ToEpoch(current)) {
+	if !params.WithinDAPeriod(slots.ToEpoch(blobSidecars[0].Slot()), slots.ToEpoch(current)) {
 		return nil
 	}
-	key := keyFromSidecar(sc[0])
+	key := keyFromSidecar(blobSidecars[0])
 	entry := s.cache.ensure(key)
-	for i := range sc {
-		if err := entry.stash(&sc[i]); err != nil {
+	for _, blobSidecar := range blobSidecars {
+		if err := entry.stash(&blobSidecar); err != nil {
 			return err
 		}
 	}
@@ -80,7 +86,7 @@ func (s *LazilyPersistentStore) Persist(current primitives.Slot, sc ...blocks.RO
 
 // IsDataAvailable returns nil if all the commitments in the given block are persisted to the db and have been verified.
 // BlobSidecars already in the db are assumed to have been previously verified against the block.
-func (s *LazilyPersistentStore) IsDataAvailable(ctx context.Context, current primitives.Slot, b blocks.ROBlock) error {
+func (s *LazilyPersistentStoreBlob) IsDataAvailable(ctx context.Context, current primitives.Slot, b blocks.ROBlock) error {
 	blockCommitments, err := commitmentsToCheck(b, current)
 	if err != nil {
 		return errors.Wrapf(err, "could not check data availability for block %#x", b.Root())

beacon-chain/das/availability_blobs_test.go

@@ -116,9 +116,11 @@ func TestLazilyPersistent_Missing(t *testing.T) {
 	ctx := context.Background()
 	store := filesystem.NewEphemeralBlobStorage(t)
 
-	blk, scs := util.GenerateTestDenebBlockWithSidecar(t, [32]byte{}, 1, 3)
+	blk, blobSidecars := util.GenerateTestDenebBlockWithSidecar(t, [32]byte{}, 1, 3)
 
-	mbv := &mockBlobBatchVerifier{t: t, scs: scs}
+	scs := blocks.NewSidecarsFromBlobSidecars(blobSidecars)
+
+	mbv := &mockBlobBatchVerifier{t: t, scs: blobSidecars}
 	as := NewLazilyPersistentStore(store, mbv)
 
 	// Only one commitment persisted, should return error with other indices
@@ -141,12 +143,14 @@ func TestLazilyPersistent_Mismatch(t *testing.T) {
 	ctx := context.Background()
 	store := filesystem.NewEphemeralBlobStorage(t)
 
-	blk, scs := util.GenerateTestDenebBlockWithSidecar(t, [32]byte{}, 1, 3)
+	blk, blobSidecars := util.GenerateTestDenebBlockWithSidecar(t, [32]byte{}, 1, 3)
 
 	mbv := &mockBlobBatchVerifier{t: t, err: errors.New("kzg check should not run")}
-	scs[0].KzgCommitment = bytesutil.PadTo([]byte("nope"), 48)
+	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]))
 	err := as.IsDataAvailable(ctx, 1, blk)
@@ -155,7 +159,10 @@ func TestLazilyPersistent_Mismatch(t *testing.T) {
 }
 
 func TestLazyPersistOnceCommitted(t *testing.T) {
-	_, scs := util.GenerateTestDenebBlockWithSidecar(t, [32]byte{}, 1, 6)
+	_, 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...))
@@ -163,10 +170,13 @@ func TestLazyPersistOnceCommitted(t *testing.T) {
 	require.ErrorIs(t, as.Persist(1, scs...), ErrDuplicateSidecar)
 
 	// ignores index out of bound
-	scs[0].Index = 6
-	require.ErrorIs(t, as.Persist(1, scs[0]), errIndexOutOfBounds)
+	blobSidecars[0].Index = 6
+	require.ErrorIs(t, as.Persist(1, blocks.NewSidecarFromBlobSidecar(blobSidecars[0])), errIndexOutOfBounds)
+
+	_, moreBlobSidecars := util.GenerateTestDenebBlockWithSidecar(t, [32]byte{}, 1, 4)
+
+	more := blocks.NewSidecarsFromBlobSidecars(moreBlobSidecars)
 
-	_, more := util.GenerateTestDenebBlockWithSidecar(t, [32]byte{}, 1, 4)
 	// ignores sidecars before the retention period
 	slotOOB, err := slots.EpochStart(params.BeaconConfig().MinEpochsForBlobsSidecarsRequest)
 	require.NoError(t, err)

beacon-chain/das/availability_columns.go

@@ -0,0 +1,208 @@
+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
+	custodyInfo            *peerdas.CustodyInfo
+	newDataColumnsVerifier verification.NewDataColumnsVerifier
+}
+
+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, custodyInfo *peerdas.CustodyInfo) *LazilyPersistentStoreColumn {
+	return &LazilyPersistentStoreColumn{
+		store:                  store,
+		nodeID:                 nodeID,
+		cache:                  newDataColumnCache(),
+		custodyInfo:            custodyInfo,
+		newDataColumnsVerifier: newDataColumnsVerifier,
+	}
+}
+
+// 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/dev/specs/fulu/p2p-interface.md#datacolumnsidecarsbyrange-v1
+	verifier := s.newDataColumnsVerifier(roDataColumns, verification.ByRangeRequestDataColumnSidecarRequirements)
+
+	if err := verifier.ValidFields(); err != nil {
+		return errors.Wrap(err, "valid")
+	}
+
+	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) {
+	// 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 spoch.
+	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 the groups count.
+	custodyGroupCount := s.custodyInfo.ActualGroupCount()
+
+	// Retrieve peer info.
+	peerInfo, _, err := peerdas.Info(nodeID, custodyGroupCount)
+	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

@@ -0,0 +1,303 @@
+package das
+
+import (
+	"context"
+	"testing"
+
+	"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/cmd/beacon-chain/flags"
+	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, &peerdas.CustodyInfo{})
+		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 := map[[fieldparams.RootLength]byte][]util.DataColumnParams{
+			{1}: {{ColumnIndex: 1}},
+			{2}: {{ColumnIndex: 2}},
+		}
+
+		roSidecars, _ := roSidecarsFromDataColumnParamsByBlockRoot(t, dataColumnParamsByBlockRoot)
+		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, enode.ID{}, nil, &peerdas.CustodyInfo{})
+
+		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 := map[[fieldparams.RootLength]byte][]util.DataColumnParams{
+			{1}: {{ColumnIndex: 1}},
+		}
+
+		roSidecars, _ := roSidecarsFromDataColumnParamsByBlockRoot(t, dataColumnParamsByBlockRoot)
+		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, enode.ID{}, nil, &peerdas.CustodyInfo{})
+
+		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) {
+		dataColumnStorage := filesystem.NewEphemeralDataColumnStorage(t)
+
+		dataColumnParamsByBlockRoot := map[[fieldparams.RootLength]byte][]util.DataColumnParams{
+			{}: {{ColumnIndex: 1}, {ColumnIndex: 5}},
+		}
+
+		roSidecars, roDataColumns := roSidecarsFromDataColumnParamsByBlockRoot(t, dataColumnParamsByBlockRoot)
+		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, enode.ID{}, nil, &peerdas.CustodyInfo{})
+
+		err := lazilyPersistentStoreColumns.Persist(0, roSidecars...)
+		require.NoError(t, err)
+		require.Equal(t, 1, len(lazilyPersistentStoreColumns.cache.entries))
+
+		key := cacheKey{slot: 0, root: [32]byte{}}
+		entry := lazilyPersistentStoreColumns.cache.entries[key]
+
+		// 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 := context.Background()
+
+	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, &peerdas.CustodyInfo{})
+
+		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)
+		root := signedRoBlock.Root()
+
+		dataColumnStorage := filesystem.NewEphemeralDataColumnStorage(t)
+		lazilyPersistentStoreColumns := NewLazilyPersistentStoreColumn(dataColumnStorage, enode.ID{}, newDataColumnsVerifier, &peerdas.CustodyInfo{})
+
+		indices := [...]uint64{1, 17, 87, 102}
+		dataColumnsParams := make([]util.DataColumnParams, 0, len(indices))
+		for _, index := range indices {
+			dataColumnParams := util.DataColumnParams{
+				ColumnIndex:    index,
+				KzgCommitments: commitments,
+			}
+
+			dataColumnsParams = append(dataColumnsParams, dataColumnParams)
+		}
+
+		dataColumnsParamsByBlockRoot := util.DataColumnsParamsByRoot{root: dataColumnsParams}
+		_, verifiedRoDataColumns := util.CreateTestVerifiedRoDataColumnSidecars(t, dataColumnsParamsByBlockRoot)
+
+		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, 0 /*current 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) {
+			resetFlags := flags.Get()
+			gFlags := new(flags.GlobalFlags)
+			gFlags.SubscribeAllDataSubnets = true
+			flags.Init(gFlags)
+			defer flags.Init(resetFlags)
+
+			b := tc.block(t)
+			s := NewLazilyPersistentStoreColumn(nil, enode.ID{}, nil, &peerdas.CustodyInfo{})
+
+			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, dataColumnParamsByBlockRoot util.DataColumnsParamsByRoot) ([]blocks.ROSidecar, []blocks.RODataColumn) {
+	roDataColumns, _ := util.CreateTestVerifiedRoDataColumnSidecars(t, dataColumnParamsByBlockRoot)
+
+	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/blob_cache.go

@@ -4,33 +4,29 @@ import (
 	"bytes"
 
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filesystem"
+	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/pkg/errors"
 )
 
-var (
-	ErrDuplicateSidecar   = errors.New("duplicate sidecar stashed in AvailabilityStore")
-	errIndexOutOfBounds   = errors.New("sidecar.index > MAX_BLOBS_PER_BLOCK")
-	errCommitmentMismatch = errors.New("KzgCommitment of sidecar in cache did not match block commitment")
-	errMissingSidecar     = errors.New("no sidecar in cache for block commitment")
-)
+var errIndexOutOfBounds = errors.New("sidecar.index > MAX_BLOBS_PER_BLOCK")
 
 // cacheKey includes the slot so that we can easily iterate through the cache and compare
 // slots for eviction purposes. Whether the input is the block or the sidecar, we always have
 // the root+slot when interacting with the cache, so it isn't an inconvenience to use both.
 type cacheKey struct {
 	slot primitives.Slot
-	root [32]byte
+	root [fieldparams.RootLength]byte
 }
 
-type cache struct {
-	entries map[cacheKey]*cacheEntry
+type blobCache struct {
+	entries map[cacheKey]*blobCacheEntry
 }
 
-func newCache() *cache {
-	return &cache{entries: make(map[cacheKey]*cacheEntry)}
+func newBlobCache() *blobCache {
+	return &blobCache{entries: make(map[cacheKey]*blobCacheEntry)}
 }
 
 // keyFromSidecar is a convenience method for constructing a cacheKey from a BlobSidecar value.
@@ -44,34 +40,34 @@ func keyFromBlock(b blocks.ROBlock) cacheKey {
 }
 
 // ensure returns the entry for the given key, creating it if it isn't already present.
-func (c *cache) ensure(key cacheKey) *cacheEntry {
+func (c *blobCache) ensure(key cacheKey) *blobCacheEntry {
 	e, ok := c.entries[key]
 	if !ok {
-		e = &cacheEntry{}
+		e = &blobCacheEntry{}
 		c.entries[key] = e
 	}
 	return e
 }
 
 // delete removes the cache entry from the cache.
-func (c *cache) delete(key cacheKey) {
+func (c *blobCache) delete(key cacheKey) {
 	delete(c.entries, key)
 }
 
-// cacheEntry holds a fixed-length cache of BlobSidecars.
-type cacheEntry struct {
+// blobCacheEntry holds a fixed-length cache of BlobSidecars.
+type blobCacheEntry struct {
 	scs         []*blocks.ROBlob
 	diskSummary filesystem.BlobStorageSummary
 }
 
-func (e *cacheEntry) setDiskSummary(sum filesystem.BlobStorageSummary) {
+func (e *blobCacheEntry) setDiskSummary(sum filesystem.BlobStorageSummary) {
 	e.diskSummary = sum
 }
 
 // stash adds an item to the in-memory cache of BlobSidecars.
 // Only the first BlobSidecar of a given Index will be kept in the cache.
 // stash will return an error if the given blob is already in the cache, or if the Index is out of bounds.
-func (e *cacheEntry) stash(sc *blocks.ROBlob) error {
+func (e *blobCacheEntry) stash(sc *blocks.ROBlob) error {
 	maxBlobsPerBlock := params.BeaconConfig().MaxBlobsPerBlock(sc.Slot())
 	if sc.Index >= uint64(maxBlobsPerBlock) {
 		return errors.Wrapf(errIndexOutOfBounds, "index=%d", sc.Index)
@@ -92,7 +88,7 @@ func (e *cacheEntry) stash(sc *blocks.ROBlob) error {
 // commitments were found in the cache and the sidecar slice return value can be used
 // to perform a DA check against the cached sidecars.
 // filter only returns blobs that need to be checked. Blobs already available on disk will be excluded.
-func (e *cacheEntry) filter(root [32]byte, kc [][]byte, slot primitives.Slot) ([]blocks.ROBlob, error) {
+func (e *blobCacheEntry) filter(root [32]byte, kc [][]byte, slot primitives.Slot) ([]blocks.ROBlob, error) {
 	count := len(kc)
 	if e.diskSummary.AllAvailable(count) {
 		return nil, nil

beacon-chain/das/blob_cache_test.go

@@ -14,7 +14,7 @@ import (
 )
 
 func TestCacheEnsureDelete(t *testing.T) {
-	c := newCache()
+	c := newBlobCache()
 	require.Equal(t, 0, len(c.entries))
 	root := bytesutil.ToBytes32([]byte("root"))
 	slot := primitives.Slot(1234)
@@ -25,18 +25,18 @@ func TestCacheEnsureDelete(t *testing.T) {
 
 	c.delete(k)
 	require.Equal(t, 0, len(c.entries))
-	var nilEntry *cacheEntry
+	var nilEntry *blobCacheEntry
 	require.Equal(t, nilEntry, c.entries[k])
 }
 
-type filterTestCaseSetupFunc func(t *testing.T) (*cacheEntry, [][]byte, []blocks.ROBlob)
+type filterTestCaseSetupFunc func(t *testing.T) (*blobCacheEntry, [][]byte, []blocks.ROBlob)
 
 func filterTestCaseSetup(slot primitives.Slot, nBlobs int, onDisk []int, numExpected int) filterTestCaseSetupFunc {
-	return func(t *testing.T) (*cacheEntry, [][]byte, []blocks.ROBlob) {
+	return func(t *testing.T) (*blobCacheEntry, [][]byte, []blocks.ROBlob) {
 		blk, blobs := util.GenerateTestDenebBlockWithSidecar(t, [32]byte{}, slot, nBlobs)
 		commits, err := commitmentsToCheck(blk, blk.Block().Slot())
 		require.NoError(t, err)
-		entry := &cacheEntry{}
+		entry := &blobCacheEntry{}
 		if len(onDisk) > 0 {
 			od := map[[32]byte][]int{blk.Root(): onDisk}
 			sumz := filesystem.NewMockBlobStorageSummarizer(t, od)
@@ -125,12 +125,12 @@ func TestFilter(t *testing.T) {
 	require.NoError(t, err)
 	cases := []struct {
 		name  string
-		setup func(t *testing.T) (*cacheEntry, [][]byte, []blocks.ROBlob)
+		setup func(t *testing.T) (*blobCacheEntry, [][]byte, []blocks.ROBlob)
 		err   error
 	}{
 		{
 			name: "commitments mismatch - extra sidecar",
-			setup: func(t *testing.T) (*cacheEntry, [][]byte, []blocks.ROBlob) {
+			setup: func(t *testing.T) (*blobCacheEntry, [][]byte, []blocks.ROBlob) {
 				entry, commits, expected := filterTestCaseSetup(denebSlot, 6, []int{0, 1}, 4)(t)
 				commits[5] = nil
 				return entry, commits, expected
@@ -139,7 +139,7 @@ func TestFilter(t *testing.T) {
 		},
 		{
 			name: "sidecar missing",
-			setup: func(t *testing.T) (*cacheEntry, [][]byte, []blocks.ROBlob) {
+			setup: func(t *testing.T) (*blobCacheEntry, [][]byte, []blocks.ROBlob) {
 				entry, commits, expected := filterTestCaseSetup(denebSlot, 6, []int{0, 1}, 4)(t)
 				entry.scs[5] = nil
 				return entry, commits, expected
@@ -148,7 +148,7 @@ func TestFilter(t *testing.T) {
 		},
 		{
 			name: "commitments mismatch - different bytes",
-			setup: func(t *testing.T) (*cacheEntry, [][]byte, []blocks.ROBlob) {
+			setup: func(t *testing.T) (*blobCacheEntry, [][]byte, []blocks.ROBlob) {
 				entry, commits, expected := filterTestCaseSetup(denebSlot, 6, []int{0, 1}, 4)(t)
 				entry.scs[5].KzgCommitment = []byte("nope")
 				return entry, commits, expected

beacon-chain/das/data_column_cache.go

@@ -0,0 +1,131 @@
+package das
+
+import (
+	"bytes"
+	"slices"
+
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filesystem"
+	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
+	"github.com/pkg/errors"
+)
+
+var (
+	ErrDuplicateSidecar   = errors.New("duplicate sidecar stashed in AvailabilityStore")
+	errColumnIndexTooHigh = errors.New("column index too high")
+	errCommitmentMismatch = errors.New("KzgCommitment of sidecar in cache did not match block commitment")
+	errMissingSidecar     = errors.New("no sidecar in cache for block commitment")
+)
+
+type dataColumnCache struct {
+	entries map[cacheKey]*dataColumnCacheEntry
+}
+
+func newDataColumnCache() *dataColumnCache {
+	return &dataColumnCache{entries: make(map[cacheKey]*dataColumnCacheEntry)}
+}
+
+// ensure returns the entry for the given key, creating it if it isn't already present.
+func (c *dataColumnCache) ensure(key cacheKey) *dataColumnCacheEntry {
+	entry, ok := c.entries[key]
+	if !ok {
+		entry = &dataColumnCacheEntry{}
+		c.entries[key] = entry
+	}
+
+	return entry
+}
+
+// delete removes the cache entry from the cache.
+func (c *dataColumnCache) delete(key cacheKey) {
+	delete(c.entries, key)
+}
+
+// dataColumnCacheEntry holds a fixed-length cache of BlobSidecars.
+type dataColumnCacheEntry struct {
+	scs         [fieldparams.NumberOfColumns]*blocks.RODataColumn
+	diskSummary filesystem.DataColumnStorageSummary
+}
+
+func (e *dataColumnCacheEntry) setDiskSummary(sum filesystem.DataColumnStorageSummary) {
+	e.diskSummary = sum
+}
+
+// stash adds an item to the in-memory cache of DataColumnSidecars.
+// Only the first DataColumnSidecar of a given Index will be kept in the cache.
+// stash will return an error if the given data colunn is already in the cache, or if the Index is out of bounds.
+func (e *dataColumnCacheEntry) stash(sc *blocks.RODataColumn) error {
+	if sc.Index >= fieldparams.NumberOfColumns {
+		return errors.Wrapf(errColumnIndexTooHigh, "index=%d", sc.Index)
+	}
+
+	if e.scs[sc.Index] != nil {
+		return errors.Wrapf(ErrDuplicateSidecar, "root=%#x, index=%d, commitment=%#x", sc.BlockRoot(), sc.Index, sc.KzgCommitments)
+	}
+
+	e.scs[sc.Index] = sc
+
+	return nil
+}
+
+func (e *dataColumnCacheEntry) filter(root [32]byte, commitmentsArray *safeCommitmentsArray) ([]blocks.RODataColumn, error) {
+	nonEmptyIndices := commitmentsArray.nonEmptyIndices()
+	if e.diskSummary.AllAvailable(nonEmptyIndices) {
+		return nil, nil
+	}
+
+	commitmentsCount := commitmentsArray.count()
+	sidecars := make([]blocks.RODataColumn, 0, commitmentsCount)
+
+	for i := range nonEmptyIndices {
+		if e.diskSummary.HasIndex(i) {
+			continue
+		}
+
+		if e.scs[i] == nil {
+			return nil, errors.Wrapf(errMissingSidecar, "root=%#x, index=%#x", root, i)
+		}
+
+		if !sliceBytesEqual(commitmentsArray[i], e.scs[i].KzgCommitments) {
+			return nil, errors.Wrapf(errCommitmentMismatch, "root=%#x, index=%#x, commitment=%#x, block commitment=%#x", root, i, e.scs[i].KzgCommitments, commitmentsArray[i])
+		}
+
+		sidecars = append(sidecars, *e.scs[i])
+	}
+
+	return sidecars, nil
+}
+
+// safeCommitmentsArray is a fixed size array of commitments.
+// This is helpful for avoiding gratuitous bounds checks.
+type safeCommitmentsArray [fieldparams.NumberOfColumns][][]byte
+
+// count returns the number of commitments in the array.
+func (s *safeCommitmentsArray) count() int {
+	count := 0
+
+	for i := range s {
+		if s[i] != nil {
+			count++
+		}
+	}
+
+	return count
+}
+
+// nonEmptyIndices returns a map of indices that are non-nil in the array.
+func (s *safeCommitmentsArray) nonEmptyIndices() map[uint64]bool {
+	columns := make(map[uint64]bool)
+
+	for i := range s {
+		if s[i] != nil {
+			columns[uint64(i)] = true
+		}
+	}
+
+	return columns
+}
+
+func sliceBytesEqual(a, b [][]byte) bool {
+	return slices.EqualFunc(a, b, bytes.Equal)
+}

beacon-chain/das/data_column_cache_test.go

@@ -0,0 +1,144 @@
+package das
+
+import (
+	"testing"
+
+	"github.com/OffchainLabs/prysm/v6/beacon-chain/db/filesystem"
+	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
+	"github.com/OffchainLabs/prysm/v6/consensus-types/blocks"
+	"github.com/OffchainLabs/prysm/v6/testing/require"
+	"github.com/OffchainLabs/prysm/v6/testing/util"
+)
+
+func TestEnsureDeleteSetDiskSummary(t *testing.T) {
+	c := newDataColumnCache()
+	key := cacheKey{}
+	entry := c.ensure(key)
+	require.DeepEqual(t, dataColumnCacheEntry{}, *entry)
+
+	diskSummary := filesystem.NewDataColumnStorageSummary(42, [fieldparams.NumberOfColumns]bool{true})
+	entry.setDiskSummary(diskSummary)
+	entry = c.ensure(key)
+	require.DeepEqual(t, dataColumnCacheEntry{diskSummary: diskSummary}, *entry)
+
+	c.delete(key)
+	entry = c.ensure(key)
+	require.DeepEqual(t, dataColumnCacheEntry{}, *entry)
+}
+
+func TestStash(t *testing.T) {
+	t.Run("Index too high", func(t *testing.T) {
+		dataColumnParamsByBlockRoot := util.DataColumnsParamsByRoot{{1}: {{ColumnIndex: 10_000}}}
+		roDataColumns, _ := util.CreateTestVerifiedRoDataColumnSidecars(t, dataColumnParamsByBlockRoot)
+
+		var entry dataColumnCacheEntry
+		err := entry.stash(&roDataColumns[0])
+		require.NotNil(t, err)
+	})
+
+	t.Run("Nominal and already existing", func(t *testing.T) {
+		dataColumnParamsByBlockRoot := util.DataColumnsParamsByRoot{{1}: {{ColumnIndex: 1}}}
+		roDataColumns, _ := util.CreateTestVerifiedRoDataColumnSidecars(t, dataColumnParamsByBlockRoot)
+
+		var entry dataColumnCacheEntry
+		err := entry.stash(&roDataColumns[0])
+		require.NoError(t, err)
+
+		require.DeepEqual(t, roDataColumns[0], entry.scs[1])
+
+		err = entry.stash(&roDataColumns[0])
+		require.NotNil(t, err)
+	})
+}
+
+func TestFilterDataColumns(t *testing.T) {
+	t.Run("All available", func(t *testing.T) {
+		commitmentsArray := safeCommitmentsArray{nil, [][]byte{[]byte{1}}, nil, [][]byte{[]byte{3}}}
+
+		diskSummary := filesystem.NewDataColumnStorageSummary(42, [fieldparams.NumberOfColumns]bool{false, true, false, true})
+
+		dataColumnCacheEntry := dataColumnCacheEntry{diskSummary: diskSummary}
+
+		actual, err := dataColumnCacheEntry.filter([fieldparams.RootLength]byte{}, &commitmentsArray)
+		require.NoError(t, err)
+		require.IsNil(t, actual)
+	})
+
+	t.Run("Some scs missing", func(t *testing.T) {
+		commitmentsArray := safeCommitmentsArray{nil, [][]byte{[]byte{1}}}
+
+		diskSummary := filesystem.NewDataColumnStorageSummary(42, [fieldparams.NumberOfColumns]bool{})
+
+		dataColumnCacheEntry := dataColumnCacheEntry{diskSummary: diskSummary}
+
+		_, err := dataColumnCacheEntry.filter([fieldparams.RootLength]byte{}, &commitmentsArray)
+		require.NotNil(t, err)
+	})
+
+	t.Run("Commitments not equal", func(t *testing.T) {
+		root := [fieldparams.RootLength]byte{}
+		commitmentsArray := safeCommitmentsArray{nil, [][]byte{[]byte{1}}}
+
+		dataColumnParamsByBlockRoot := util.DataColumnsParamsByRoot{root: {{ColumnIndex: 1}}}
+		roDataColumns, _ := util.CreateTestVerifiedRoDataColumnSidecars(t, dataColumnParamsByBlockRoot)
+
+		var scs [fieldparams.NumberOfColumns]*blocks.RODataColumn
+		scs[1] = &roDataColumns[0]
+
+		dataColumnCacheEntry := dataColumnCacheEntry{scs: scs}
+
+		_, err := dataColumnCacheEntry.filter(root, &commitmentsArray)
+		require.NotNil(t, err)
+	})
+
+	t.Run("Nominal", func(t *testing.T) {
+		root := [fieldparams.RootLength]byte{}
+		commitmentsArray := safeCommitmentsArray{nil, [][]byte{[]byte{1}}, nil, [][]byte{[]byte{3}}}
+
+		diskSummary := filesystem.NewDataColumnStorageSummary(42, [fieldparams.NumberOfColumns]bool{false, true})
+
+		dataColumnParamsByBlockRoot := util.DataColumnsParamsByRoot{root: {{ColumnIndex: 3, KzgCommitments: [][]byte{[]byte{3}}}}}
+		expected, _ := util.CreateTestVerifiedRoDataColumnSidecars(t, dataColumnParamsByBlockRoot)
+
+		var scs [fieldparams.NumberOfColumns]*blocks.RODataColumn
+		scs[3] = &expected[0]
+
+		dataColumnCacheEntry := dataColumnCacheEntry{scs: scs, diskSummary: diskSummary}
+
+		actual, err := dataColumnCacheEntry.filter(root, &commitmentsArray)
+		require.NoError(t, err)
+
+		require.DeepEqual(t, expected, actual)
+	})
+}
+
+func TestCount(t *testing.T) {
+	s := safeCommitmentsArray{nil, [][]byte{[]byte{1}}, nil, [][]byte{[]byte{3}}}
+	require.Equal(t, 2, s.count())
+}
+
+func TestNonEmptyIndices(t *testing.T) {
+	s := safeCommitmentsArray{nil, [][]byte{[]byte{10}}, nil, [][]byte{[]byte{20}}}
+	actual := s.nonEmptyIndices()
+	require.DeepEqual(t, map[uint64]bool{1: true, 3: true}, actual)
+}
+
+func TestSliceBytesEqual(t *testing.T) {
+	t.Run("Different lengths", func(t *testing.T) {
+		a := [][]byte{[]byte{1, 2, 3}}
+		b := [][]byte{[]byte{1, 2, 3}, []byte{4, 5, 6}}
+		require.Equal(t, false, sliceBytesEqual(a, b))
+	})
+
+	t.Run("Same length but different content", func(t *testing.T) {
+		a := [][]byte{[]byte{1, 2, 3}, []byte{4, 5, 6}}
+		b := [][]byte{[]byte{1, 2, 3}, []byte{4, 5, 7}}
+		require.Equal(t, false, sliceBytesEqual(a, b))
+	})
+
+	t.Run("Equal slices", func(t *testing.T) {
+		a := [][]byte{[]byte{1, 2, 3}, []byte{4, 5, 6}}
+		b := [][]byte{[]byte{1, 2, 3}, []byte{4, 5, 6}}
+		require.Equal(t, true, sliceBytesEqual(a, b))
+	})
+}

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.ROBlob) error
+	Persist(current primitives.Slot, sc ...blocks.ROSidecar) error
 }

beacon-chain/das/mock.go

@@ -5,6 +5,7 @@ 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.
@@ -24,9 +25,13 @@ 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.ROBlob) error {
+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")
+	}
 	if m.PersistBlobsCallback != nil {
-		return m.PersistBlobsCallback(current, sc...)
+		return m.PersistBlobsCallback(current, blobSidecars...)
 	}
 	return nil
 }

beacon-chain/sync/backfill/blobs.go

@@ -90,7 +90,10 @@ func (bs *blobSync) validateNext(rb blocks.ROBlob) error {
 	if err := v.SidecarKzgProofVerified(); err != nil {
 		return err
 	}
-	if err := bs.store.Persist(bs.current, rb); err != nil {
+
+	sc := blocks.NewSidecarFromBlobSidecar(rb)
+
+	if err := bs.store.Persist(bs.current, sc); err != nil {
 		return err
 	}
 

beacon-chain/sync/initial-sync/round_robin.go

@@ -166,7 +166,8 @@ func (s *Service) processFetchedDataRegSync(ctx context.Context, data *blocksQue
 		"firstUnprocessed": bwb[0].Block.Block().Slot(),
 	}
 	for i, b := range bwb {
-		if err := avs.Persist(s.clock.CurrentSlot(), b.Blobs...); err != nil {
+		sidecars := blocks.NewSidecarsFromBlobSidecars(b.Blobs)
+		if err := avs.Persist(s.clock.CurrentSlot(), sidecars...); err != nil {
 			log.WithError(err).WithFields(batchFields).WithFields(syncFields(b.Block)).Warn("Batch failure due to BlobSidecar issues")
 			return uint64(i), err
 		}
@@ -324,7 +325,10 @@ func (s *Service) processBatchedBlocks(ctx context.Context, bwb []blocks.BlockWi
 		if len(bb.Blobs) == 0 {
 			continue
 		}
-		if err := avs.Persist(s.clock.CurrentSlot(), bb.Blobs...); err != nil {
+
+		sidecars := blocks.NewSidecarsFromBlobSidecars(bb.Blobs)
+
+		if err := avs.Persist(s.clock.CurrentSlot(), sidecars...); err != nil {
 			return 0, err
 		}
 	}

beacon-chain/sync/initial-sync/service.go

@@ -331,16 +331,17 @@ func (s *Service) fetchOriginBlobs(pids []peer.ID) error {
 	}
 	shufflePeers(pids)
 	for i := range pids {
-		sidecars, err := sync.SendBlobSidecarByRoot(s.ctx, s.clock, s.cfg.P2P, pids[i], s.ctxMap, &req, rob.Block().Slot())
+		blobSidecars, err := sync.SendBlobSidecarByRoot(s.ctx, s.clock, s.cfg.P2P, pids[i], s.ctxMap, &req, rob.Block().Slot())
 		if err != nil {
 			continue
 		}
-		if len(sidecars) != len(req) {
+		if len(blobSidecars) != len(req) {
 			continue
 		}
 		bv := verification.NewBlobBatchVerifier(s.newBlobVerifier, verification.InitsyncBlobSidecarRequirements)
 		avs := das.NewLazilyPersistentStore(s.cfg.BlobStorage, bv)
 		current := s.clock.CurrentSlot()
+		sidecars := blocks.NewSidecarsFromBlobSidecars(blobSidecars)
 		if err := avs.Persist(current, sidecars...); err != nil {
 			return err
 		}
@@ -348,7 +349,7 @@ func (s *Service) fetchOriginBlobs(pids []peer.ID) error {
 			log.WithField("root", fmt.Sprintf("%#x", r)).WithField("peerID", pids[i]).Warn("Blobs from peer for origin block were unusable")
 			continue
 		}
-		log.WithField("nBlobs", len(sidecars)).WithField("root", fmt.Sprintf("%#x", r)).Info("Successfully downloaded blobs for checkpoint sync block")
+		log.WithField("nBlobs", len(blobSidecars)).WithField("root", fmt.Sprintf("%#x", r)).Info("Successfully downloaded blobs for checkpoint sync block")
 		return nil
 	}
 	return fmt.Errorf("no connected peer able to provide blobs for checkpoint sync block %#x", r)

beacon-chain/verification/data_column.go

@@ -38,6 +38,15 @@ var (
 		RequireSidecarProposerExpected,
 	}
 
+	// ByRangeRequestDataColumnSidecarRequirements defines the set of requirements that DataColumnSidecars received
+	// via the by range request must satisfy in order to upgrade an RODataColumn to a VerifiedRODataColumn.
+	// https://github.com/ethereum/consensus-specs/blob/dev/specs/fulu/p2p-interface.md#datacolumnsidecarsbyrange-v1
+	ByRangeRequestDataColumnSidecarRequirements = []Requirement{
+		RequireValidFields,
+		RequireSidecarInclusionProven,
+		RequireSidecarKzgProofVerified,
+	}
+
 	errColumnsInvalid = errors.New("data columns failed verification")
 	errBadTopicLength = errors.New("topic length is invalid")
 	errBadTopic       = errors.New("topic is not of the one expected")

changelog/manu-peerdas-das.md

@@ -0,0 +1,2 @@
+### Added 
+- PeerDAS: Implement DAS.

consensus-types/blocks/BUILD.bazel

@@ -13,6 +13,7 @@ go_library(
         "roblob.go",
         "roblock.go",
         "rodatacolumn.go",
+        "rosidecar.go",
         "setters.go",
         "types.go",
     ],
@@ -53,6 +54,7 @@ go_test(
         "roblob_test.go",
         "roblock_test.go",
         "rodatacolumn_test.go",
+        "rosidecar_test.go",
     ],
     embed = [":go_default_library"],
     deps = [
@@ -72,5 +74,6 @@ go_test(
         "@com_github_prysmaticlabs_fastssz//:go_default_library",
         "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
         "@com_github_prysmaticlabs_gohashtree//:go_default_library",
+        "@com_github_stretchr_testify//require:go_default_library",
     ],
 )

consensus-types/blocks/rosidecar.go

@@ -0,0 +1,96 @@
+package blocks
+
+import (
+	"github.com/pkg/errors"
+)
+
+// ROSidecar represents a read-only sidecar with its block root.
+type ROSidecar struct {
+	blob       *ROBlob
+	dataColumn *RODataColumn
+}
+
+var (
+	errBlobNeeded       = errors.New("blob sidecar needed")
+	errDataColumnNeeded = errors.New("data column sidecar needed")
+)
+
+// NewSidecarFromBlobSidecar creates a new read-only (generic) sidecar from a read-only blob sidecar.
+func NewSidecarFromBlobSidecar(blob ROBlob) ROSidecar {
+	return ROSidecar{blob: &blob}
+}
+
+// NewSidecarFromDataColumnSidecar creates a new read-only (generic) sidecar from a read-only data column sidecar.
+func NewSidecarFromDataColumnSidecar(dataColumn RODataColumn) ROSidecar {
+	return ROSidecar{dataColumn: &dataColumn}
+}
+
+// NewSidecarsFromBlobSidecars creates a new slice of read-only (generic) sidecars from a slice of read-only blobs sidecars.
+func NewSidecarsFromBlobSidecars(blobSidecars []ROBlob) []ROSidecar {
+	sidecars := make([]ROSidecar, 0, len(blobSidecars))
+	for _, blob := range blobSidecars {
+		blobSidecar := ROSidecar{blob: &blob} // #nosec G601
+		sidecars = append(sidecars, blobSidecar)
+	}
+
+	return sidecars
+}
+
+// NewSidecarsFromDataColumnSidecars creates a new slice of read-only (generic) sidecars from a slice of read-only data column sidecars.
+func NewSidecarsFromDataColumnSidecars(dataColumnSidecars []RODataColumn) []ROSidecar {
+	sidecars := make([]ROSidecar, 0, len(dataColumnSidecars))
+	for _, dataColumn := range dataColumnSidecars {
+		dataColumnSidecar := ROSidecar{dataColumn: &dataColumn} // #nosec G601
+		sidecars = append(sidecars, dataColumnSidecar)
+	}
+
+	return sidecars
+}
+
+// Blob returns the blob sidecar.
+func (sc *ROSidecar) Blob() (ROBlob, error) {
+	if sc.blob == nil {
+		return ROBlob{}, errBlobNeeded
+	}
+
+	return *sc.blob, nil
+}
+
+// DataColumn returns the data column sidecar.
+func (sc *ROSidecar) DataColumn() (RODataColumn, error) {
+	if sc.dataColumn == nil {
+		return RODataColumn{}, errDataColumnNeeded
+	}
+
+	return *sc.dataColumn, nil
+}
+
+// BlobSidecarsFromSidecars creates a new slice of read-only blobs sidecars from a slice of read-only (generic) sidecars.
+func BlobSidecarsFromSidecars(sidecars []ROSidecar) ([]ROBlob, error) {
+	blobSidecars := make([]ROBlob, 0, len(sidecars))
+	for _, sidecar := range sidecars {
+		blob, err := sidecar.Blob()
+		if err != nil {
+			return nil, errors.Wrap(err, "blob")
+		}
+
+		blobSidecars = append(blobSidecars, blob)
+	}
+
+	return blobSidecars, nil
+}
+
+// DataColumnSidecarsFromSidecars creates a new slice of read-only data column sidecars from a slice of read-only (generic) sidecars.
+func DataColumnSidecarsFromSidecars(sidecars []ROSidecar) ([]RODataColumn, error) {
+	dataColumnSidecars := make([]RODataColumn, 0, len(sidecars))
+	for _, sidecar := range sidecars {
+		dataColumn, err := sidecar.DataColumn()
+		if err != nil {
+			return nil, errors.Wrap(err, "data column")
+		}
+
+		dataColumnSidecars = append(dataColumnSidecars, dataColumn)
+	}
+
+	return dataColumnSidecars, nil
+}

consensus-types/blocks/rosidecar_test.go

@@ -0,0 +1,109 @@
+package blocks
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestNewSidecarFromBlobSidecar(t *testing.T) {
+	blob := ROBlob{}
+	sidecar := NewSidecarFromBlobSidecar(blob)
+
+	// Check that the blob is set
+	retrievedBlob, err := sidecar.Blob()
+	require.NoError(t, err)
+	require.Equal(t, blob, retrievedBlob)
+
+	// Check that data column is not set
+	_, err = sidecar.DataColumn()
+	require.ErrorIs(t, err, errDataColumnNeeded)
+}
+
+func TestNewSidecarFromDataColumnSidecar(t *testing.T) {
+	dataColumn := RODataColumn{}
+	sidecar := NewSidecarFromDataColumnSidecar(dataColumn)
+
+	// Check that the data column is set
+	retrievedDataColumn, err := sidecar.DataColumn()
+	require.NoError(t, err)
+	require.Equal(t, dataColumn, retrievedDataColumn)
+
+	// Check that blob is not set
+	_, err = sidecar.Blob()
+	require.ErrorIs(t, err, errBlobNeeded)
+}
+
+func TestNewSidecarsFromBlobSidecars(t *testing.T) {
+	blobSidecars := []ROBlob{{}, {}}
+	sidecars := NewSidecarsFromBlobSidecars(blobSidecars)
+
+	require.Equal(t, len(blobSidecars), len(sidecars))
+
+	for i, sidecar := range sidecars {
+		retrievedBlob, err := sidecar.Blob()
+		require.NoError(t, err)
+		require.Equal(t, blobSidecars[i], retrievedBlob)
+	}
+}
+
+func TestNewSidecarsFromDataColumnSidecars(t *testing.T) {
+	dataColumnSidecars := []RODataColumn{{}, {}}
+	sidecars := NewSidecarsFromDataColumnSidecars(dataColumnSidecars)
+
+	require.Equal(t, len(dataColumnSidecars), len(sidecars))
+
+	for i, sidecar := range sidecars {
+		retrievedDataColumn, err := sidecar.DataColumn()
+		require.NoError(t, err)
+		require.Equal(t, dataColumnSidecars[i], retrievedDataColumn)
+	}
+}
+
+func TestBlobSidecarsFromSidecars(t *testing.T) {
+	// Create sidecars with blobs
+	blobSidecars := []ROBlob{{}, {}}
+	sidecars := NewSidecarsFromBlobSidecars(blobSidecars)
+
+	// Convert back to blob sidecars
+	retrievedBlobSidecars, err := BlobSidecarsFromSidecars(sidecars)
+	require.NoError(t, err)
+	require.Equal(t, len(blobSidecars), len(retrievedBlobSidecars))
+
+	for i, blob := range retrievedBlobSidecars {
+		require.Equal(t, blobSidecars[i], blob)
+	}
+
+	// Test with a mix of sidecar types
+	mixedSidecars := []ROSidecar{
+		NewSidecarFromBlobSidecar(ROBlob{}),
+		NewSidecarFromDataColumnSidecar(RODataColumn{}),
+	}
+
+	_, err = BlobSidecarsFromSidecars(mixedSidecars)
+	require.Error(t, err)
+}
+
+func TestDataColumnSidecarsFromSidecars(t *testing.T) {
+	// Create sidecars with data columns
+	dataColumnSidecars := []RODataColumn{{}, {}}
+	sidecars := NewSidecarsFromDataColumnSidecars(dataColumnSidecars)
+
+	// Convert back to data column sidecars
+	retrievedDataColumnSidecars, err := DataColumnSidecarsFromSidecars(sidecars)
+	require.NoError(t, err)
+	require.Equal(t, len(dataColumnSidecars), len(retrievedDataColumnSidecars))
+
+	for i, dataColumn := range retrievedDataColumnSidecars {
+		require.Equal(t, dataColumnSidecars[i], dataColumn)
+	}
+
+	// Test with a mix of sidecar types
+	mixedSidecars := []ROSidecar{
+		NewSidecarFromDataColumnSidecar(RODataColumn{}),
+		NewSidecarFromBlobSidecar(ROBlob{}),
+	}
+
+	_, err = DataColumnSidecarsFromSidecars(mixedSidecars)
+	require.Error(t, err)
+}