Add nim-kzg4844 and use it in validate_blobs (#4732)

.gitmodules

@@ -203,3 +203,6 @@
 [submodule "vendor/withdrawals-testnets"]
 	path = vendor/withdrawals-testnets
 	url = https://github.com/ethpandaops/withdrawals-testnet.git
+[submodule "vendor/nim-kzg4844"]
+	path = vendor/nim-kzg4844
+	url = https://github.com/status-im/nim-kzg4844/

beacon_chain/gossip_processing/block_processor.nim

@@ -26,7 +26,6 @@ from ../consensus_object_pools/block_quarantine import
 from ../validators/validator_monitor import
   MsgSource, ValidatorMonitor, registerAttestationInBlock, registerBeaconBlock,
   registerSyncAggregateInBlock
-from ../spec/state_transition_block import validate_blobs_sidecar
 
 export sszdump, signatures_batch
 

beacon_chain/spec/datatypes/deneb.nim

@@ -24,7 +24,9 @@ import
   ../digest,
   "."/[base, phase0, altair, bellatrix, capella]
 
-export json_serialization, base
+from  ../../vendor/nim-kzg4844/kzg4844 import KZGCommitment, KZGProof
+
+export json_serialization, base, kzg4844
 
 const
   # https://github.com/ethereum/consensus-specs/blob/v1.3.0-rc.3/specs/deneb/polynomial-commitments.md#constants
@@ -39,11 +41,6 @@ const
   MIN_EPOCHS_FOR_BLOB_SIDECARS_REQUESTS* = 4096'u64
 
 type
-  # this block belongs elsewhere - will figure out after implementing c-kzg bindings
-  KZGCommitment* = array[48, byte]
-  KZGProof* = array[48, byte]
-  BLSFieldElement* = array[32, byte]
-
   KZGCommitments* = List[KZGCommitment, Limit MAX_BLOBS_PER_BLOCK]
   Blobs* = List[Blob, Limit MAX_BLOBS_PER_BLOCK]
 

beacon_chain/spec/state_transition_block.nim

@@ -22,8 +22,9 @@
 import
   chronicles, metrics,
   ../extras,
-  ./datatypes/[phase0, altair, bellatrix],
-  "."/[beaconstate, eth2_merkleization, helpers, validator, signatures]
+  ./datatypes/[phase0, altair, bellatrix, deneb],
+  "."/[beaconstate, eth2_merkleization, helpers, validator, signatures],
+  kzg4844/kzg_abi, kzg4844/kzg_ex
 
 from std/algorithm import fill, sorted
 from std/sequtils import count, filterIt, mapIt
@@ -751,23 +752,19 @@ func process_blob_kzg_commitments(
   else:
     return err("process_blob_kzg_commitments: verify_kzg_commitments_against_transactions failed")
 
-# https://github.com/ethereum/consensus-specs/blob/v1.3.0-alpha.2/specs/eip4844/beacon-chain.md#validate_blobs_sidecar
-proc validate_blobs_sidecar*(slot: Slot, root: Eth2Digest,
-                          expected_kzg_commitments: seq[deneb.KZGCommitment],
-                          blobs_sidecar: deneb.BlobsSidecar):
-                            Result[void, cstring] =
-  if slot != blobs_sidecar.beacon_block_slot:
-    return err("validate_blobs_sidecar: different slot in block and sidecar")
+# https://github.com/ethereum/consensus-specs/blob/v1.3.0-rc.3/specs/deneb/fork-choice.md#validate_blobs
+proc validate_blobs*(expected_kzg_commitments: seq[KZGCommitment],
+                     blobs: seq[KzgBlob],
+                     proofs: seq[KZGProof]):
+                       Result[void, cstring] =
+  if expected_kzg_commitments.len != blobs.len:
+    return err("validate_blobs: different commitment and blob lengths")
 
-  if root != blobs_sidecar.beacon_block_root:
-    return err("validate_blobs_sidecar: different root in block and sidecar")
+  if proofs.len != blobs.len:
+    return err("validate_blobs: different proof and blob lengths")
 
-  if expected_kzg_commitments.len != blobs_sidecar.blobs.len:
-    return err("validate_blobs_sidecar: different commitment lengths")
-
-  # TODO
-  # if not kzg_4844.verify_aggregate_kzg_proof(asSeq(blobs_sidecar.blobs), expected_kzg_commitments, blobs_sidecar.kzg_aggregated_proof):
-  #  return err("validate_blobs_sidecar: aggregated kzg proof verification failed")
+  if verifyProofs(blobs, expected_kzg_commitments, proofs).isErr():
+    return err("validate_blobs: proof verification failed")
 
   ok()
 

config.nims

@@ -193,6 +193,9 @@ switch("hint", "XCannotRaiseY:off")
 # Useful for Chronos metrics.
 #--define:chronosFutureTracking
 
+--define:kzgExternalBlst
+--define:kzgExternalBlstNoSha256
+
 # ############################################################
 #
 #                    No LTO for crypto

vendor/nim-kzg4844

@@ -0,0 +1 @@
+Subproject commit 95978add33f743efcd46725c38fc074d96f7b5fb