Offloading KZG Proof Computation from the beacon node (#7117)

Addresses #7108

- Add EL integration for `getPayloadV5` and `getBlobsV2`
- Offload proof computation and use proofs from EL RPC APIs

consensus/types/src/data_column_sidecar.rs

@@ -1,7 +1,7 @@
 use crate::beacon_block_body::{KzgCommitments, BLOB_KZG_COMMITMENTS_INDEX};
 use crate::test_utils::TestRandom;
 use crate::BeaconStateError;
-use crate::{BeaconBlockHeader, Epoch, EthSpec, Hash256, KzgProofs, SignedBeaconBlockHeader, Slot};
+use crate::{BeaconBlockHeader, Epoch, EthSpec, Hash256, SignedBeaconBlockHeader, Slot};
 use bls::Signature;
 use derivative::Derivative;
 use kzg::Error as KzgError;
@@ -56,7 +56,7 @@ pub struct DataColumnSidecar<E: EthSpec> {
     pub column: DataColumn<E>,
     /// All the KZG commitments and proofs associated with the block, used for verifying sample cells.
     pub kzg_commitments: KzgCommitments<E>,
-    pub kzg_proofs: KzgProofs<E>,
+    pub kzg_proofs: VariableList<KzgProof, E::MaxBlobCommitmentsPerBlock>,
     pub signed_block_header: SignedBeaconBlockHeader,
     /// An inclusion proof, proving the inclusion of `blob_kzg_commitments` in `BeaconBlockBody`.
     pub kzg_commitments_inclusion_proof: FixedVector<Hash256, E::KzgCommitmentsInclusionProofDepth>,

consensus/types/src/eth_spec.rs

@@ -4,8 +4,8 @@ use safe_arith::SafeArith;
 use serde::{Deserialize, Serialize};
 use ssz_types::typenum::{
     bit::B0, UInt, U0, U1, U10, U1024, U1048576, U1073741824, U1099511627776, U128, U131072,
-    U134217728, U16, U16777216, U17, U2, U2048, U256, U262144, U32, U4, U4096, U512, U625, U64,
-    U65536, U8, U8192,
+    U134217728, U16, U16777216, U17, U2, U2048, U256, U262144, U32, U33554432, U4, U4096, U512,
+    U625, U64, U65536, U8, U8192,
 };
 use std::fmt::{self, Debug};
 use std::str::FromStr;
@@ -146,6 +146,11 @@ pub trait EthSpec:
     /// Must be set to `BytesPerFieldElement * FieldElementsPerCell`.
     type BytesPerCell: Unsigned + Clone + Sync + Send + Debug + PartialEq;
 
+    /// The maximum number of cell commitments per block
+    ///
+    /// FieldElementsPerExtBlob * MaxBlobCommitmentsPerBlock
+    type MaxCellsPerBlock: Unsigned + Clone + Sync + Send + Debug + PartialEq;
+
     /*
      * New in Electra
      */
@@ -421,6 +426,7 @@ impl EthSpec for MainnetEthSpec {
     type FieldElementsPerExtBlob = U8192;
     type BytesPerBlob = U131072;
     type BytesPerCell = U2048;
+    type MaxCellsPerBlock = U33554432;
     type KzgCommitmentInclusionProofDepth = U17;
     type KzgCommitmentsInclusionProofDepth = U4; // inclusion of the whole list of commitments
     type SyncSubcommitteeSize = U128; // 512 committee size / 4 sync committee subnet count
@@ -474,6 +480,7 @@ impl EthSpec for MinimalEthSpec {
     type MaxWithdrawalRequestsPerPayload = U2;
     type FieldElementsPerCell = U64;
     type FieldElementsPerExtBlob = U8192;
+    type MaxCellsPerBlock = U33554432;
     type BytesPerCell = U2048;
     type KzgCommitmentsInclusionProofDepth = U4;
 
@@ -566,6 +573,7 @@ impl EthSpec for GnosisEthSpec {
     type MaxPendingDepositsPerEpoch = U16;
     type FieldElementsPerCell = U64;
     type FieldElementsPerExtBlob = U8192;
+    type MaxCellsPerBlock = U33554432;
     type BytesPerCell = U2048;
     type KzgCommitmentsInclusionProofDepth = U4;
 

consensus/types/src/lib.rs

@@ -272,7 +272,14 @@ pub type Address = fixed_bytes::Address;
 pub type ForkVersion = [u8; 4];
 pub type BLSFieldElement = Uint256;
 pub type Blob<E> = FixedVector<u8, <E as EthSpec>::BytesPerBlob>;
-pub type KzgProofs<E> = VariableList<KzgProof, <E as EthSpec>::MaxBlobCommitmentsPerBlock>;
+// Note on List limit:
+// - Deneb to Electra: `MaxBlobCommitmentsPerBlock`
+// - Fulu: `MaxCellsPerBlock`
+// We choose to use a single type (with the larger value from Fulu as `N`) instead of having to
+// introduce a new type for Fulu. This is to avoid messy conversions and having to add extra types
+// with no gains - as `N` does not impact serialisation at all, and only affects merkleization,
+// which we don't current do on `KzgProofs` anyway.
+pub type KzgProofs<E> = VariableList<KzgProof, <E as EthSpec>::MaxCellsPerBlock>;
 pub type VersionedHash = Hash256;
 pub type Hash64 = alloy_primitives::B64;