Update kzg interface (#4077)

* Update kzg interface

* Update utils

* Update dependency

* Address review comments

beacon_node/beacon_chain/src/kzg_utils.rs

@@ -1,54 +1,57 @@
 use kzg::{Error as KzgError, Kzg, BYTES_PER_BLOB};
-use types::{Blob, BlobsSidecar, EthSpec, Hash256, KzgCommitment, KzgProof, Slot};
+use types::{Blob, EthSpec, KzgCommitment, KzgProof};
 
+/// Converts a blob ssz List object to an array to be used with the kzg
+/// crypto library.
 fn ssz_blob_to_crypto_blob<T: EthSpec>(blob: Blob<T>) -> kzg::Blob {
     let blob_vec: Vec<u8> = blob.into();
     let mut arr = [0; BYTES_PER_BLOB];
     arr.copy_from_slice(&blob_vec);
     arr.into()
 }
 
-pub fn validate_blobs_sidecar<T: EthSpec>(
+/// Validate a single blob-commitment-proof triplet from a `BlobSidecar`.
+pub fn validate_blob<T: EthSpec>(
     kzg: &Kzg,
-    slot: Slot,
-    beacon_block_root: Hash256,
-    expected_kzg_commitments: &[KzgCommitment],
-    blobs_sidecar: &BlobsSidecar<T>,
+    blob: Blob<T>,
+    kzg_commitment: KzgCommitment,
+    kzg_proof: KzgProof,
 ) -> Result<bool, KzgError> {
-    if slot != blobs_sidecar.beacon_block_slot
-        || beacon_block_root != blobs_sidecar.beacon_block_root
-        || blobs_sidecar.blobs.len() != expected_kzg_commitments.len()
-    {
-        return Ok(false);
-    }
-
-    let blobs = blobs_sidecar
-        .blobs
-        .clone() // TODO(pawan): avoid this clone
-        .into_iter()
-        .map(|blob| ssz_blob_to_crypto_blob::<T>(blob))
-        .collect::<Vec<_>>();
-
-    kzg.verify_aggregate_kzg_proof(
-        &blobs,
-        expected_kzg_commitments,
-        blobs_sidecar.kzg_aggregated_proof,
+    kzg.verify_blob_kzg_proof(
+        ssz_blob_to_crypto_blob::<T>(blob),
+        kzg_commitment,
+        kzg_proof,
     )
 }
 
-pub fn compute_aggregate_kzg_proof<T: EthSpec>(
+/// Validate a batch of blob-commitment-proof triplets from multiple `BlobSidecars`.
+pub fn validate_blobs<T: EthSpec>(
     kzg: &Kzg,
+    expected_kzg_commitments: &[KzgCommitment],
     blobs: &[Blob<T>],
-) -> Result<KzgProof, KzgError> {
+    kzg_proofs: &[KzgProof],
+) -> Result<bool, KzgError> {
     let blobs = blobs
         .iter()
-        .map(|blob| ssz_blob_to_crypto_blob::<T>(blob.clone())) // TODO(pawan): avoid this clone
+        .map(|blob| ssz_blob_to_crypto_blob::<T>(blob.clone())) // Avoid this clone
         .collect::<Vec<_>>();
 
-    kzg.compute_aggregate_kzg_proof(&blobs)
+    kzg.verify_blob_kzg_proof_batch(&blobs, expected_kzg_commitments, kzg_proofs)
+}
+
+/// Compute the kzg proof given an ssz blob and its kzg commitment.
+pub fn compute_blob_kzg_proof<T: EthSpec>(
+    kzg: &Kzg,
+    blob: Blob<T>,
+    kzg_commitment: KzgCommitment,
+) -> Result<KzgProof, KzgError> {
+    kzg.compute_blob_kzg_proof(ssz_blob_to_crypto_blob::<T>(blob), kzg_commitment)
 }
 
-pub fn blob_to_kzg_commitment<T: EthSpec>(kzg: &Kzg, blob: Blob<T>) -> KzgCommitment {
-    let blob = ssz_blob_to_crypto_blob::<T>(blob);
-    kzg.blob_to_kzg_commitment(blob)
+/// Compute the kzg commitment for a given blob.
+pub fn blob_to_kzg_commitment<T: EthSpec>(
+    kzg: &Kzg,
+    blob: Blob<T>,
+) -> Result<KzgCommitment, KzgError> {
+    kzg.blob_to_kzg_commitment(ssz_blob_to_crypto_blob::<T>(blob))
 }

crypto/kzg/Cargo.toml

@@ -16,7 +16,7 @@ serde_derive = "1.0.116"
 eth2_serde_utils = "0.1.1"
 hex = "0.4.2"
 eth2_hashing = "0.3.0"
-c-kzg = {git = "https://github.com/ethereum/c-kzg-4844", rev = "69f6155d7524247be9d3f54ab3bfbe33a0345622" }
+c-kzg = {git = "https://github.com/ethereum/c-kzg-4844", rev = "549739fcb3aaec6fe5651e1912f05c604b45621b" }
 arbitrary = { version = "1.0", features = ["derive"], optional = true }
 
 [features]

crypto/kzg/src/kzg_commitment.rs

@@ -1,3 +1,4 @@
+use c_kzg::{Bytes48, BYTES_PER_COMMITMENT};
 use derivative::Derivative;
 use serde::de::{Deserialize, Deserializer};
 use serde::ser::{Serialize, Serializer};
@@ -7,12 +8,16 @@ use std::fmt::{Debug, Display, Formatter};
 use std::str::FromStr;
 use tree_hash::{PackedEncoding, TreeHash};
 
-const KZG_COMMITMENT_BYTES_LEN: usize = 48;
-
 #[derive(Derivative, Clone, Encode, Decode)]
 #[derivative(PartialEq, Eq, Hash)]
 #[ssz(struct_behaviour = "transparent")]
-pub struct KzgCommitment(pub [u8; KZG_COMMITMENT_BYTES_LEN]);
+pub struct KzgCommitment(pub [u8; BYTES_PER_COMMITMENT]);
+
+impl From<KzgCommitment> for Bytes48 {
+    fn from(value: KzgCommitment) -> Self {
+        value.0.into()
+    }
+}
 
 impl Display for KzgCommitment {
     fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
@@ -22,21 +27,21 @@ impl Display for KzgCommitment {
 
 impl Default for KzgCommitment {
     fn default() -> Self {
-        KzgCommitment([0; KZG_COMMITMENT_BYTES_LEN])
+        KzgCommitment([0; BYTES_PER_COMMITMENT])
     }
 }
 
 impl TreeHash for KzgCommitment {
     fn tree_hash_type() -> tree_hash::TreeHashType {
-        <[u8; KZG_COMMITMENT_BYTES_LEN] as TreeHash>::tree_hash_type()
+        <[u8; BYTES_PER_COMMITMENT] as TreeHash>::tree_hash_type()
     }
 
     fn tree_hash_packed_encoding(&self) -> PackedEncoding {
         self.0.tree_hash_packed_encoding()
     }
 
     fn tree_hash_packing_factor() -> usize {
-        <[u8; KZG_COMMITMENT_BYTES_LEN] as TreeHash>::tree_hash_packing_factor()
+        <[u8; BYTES_PER_COMMITMENT] as TreeHash>::tree_hash_packing_factor()
     }
 
     fn tree_hash_root(&self) -> tree_hash::Hash256 {
@@ -86,15 +91,15 @@ impl FromStr for KzgCommitment {
     fn from_str(s: &str) -> Result<Self, Self::Err> {
         if let Some(stripped) = s.strip_prefix("0x") {
             let bytes = hex::decode(stripped).map_err(|e| e.to_string())?;
-            if bytes.len() == KZG_COMMITMENT_BYTES_LEN {
-                let mut kzg_commitment_bytes = [0; KZG_COMMITMENT_BYTES_LEN];
+            if bytes.len() == BYTES_PER_COMMITMENT {
+                let mut kzg_commitment_bytes = [0; BYTES_PER_COMMITMENT];
                 kzg_commitment_bytes[..].copy_from_slice(&bytes);
                 Ok(Self(kzg_commitment_bytes))
             } else {
                 Err(format!(
                     "InvalidByteLength: got {}, expected {}",
                     bytes.len(),
-                    KZG_COMMITMENT_BYTES_LEN
+                    BYTES_PER_COMMITMENT
                 ))
             }
         } else {
@@ -112,7 +117,7 @@ impl Debug for KzgCommitment {
 #[cfg(feature = "arbitrary")]
 impl arbitrary::Arbitrary<'_> for KzgCommitment {
     fn arbitrary(u: &mut arbitrary::Unstructured<'_>) -> arbitrary::Result<Self> {
-        let mut bytes = [0u8; KZG_COMMITMENT_BYTES_LEN];
+        let mut bytes = [0u8; BYTES_PER_COMMITMENT];
         u.fill_buffer(&mut bytes)?;
         Ok(KzgCommitment(bytes))
     }

crypto/kzg/src/kzg_proof.rs

@@ -1,3 +1,4 @@
+use c_kzg::{Bytes48, BYTES_PER_PROOF};
 use serde::de::{Deserialize, Deserializer};
 use serde::ser::{Serialize, Serializer};
 use ssz_derive::{Decode, Encode};
@@ -6,15 +7,19 @@ use std::fmt::Debug;
 use std::str::FromStr;
 use tree_hash::{PackedEncoding, TreeHash};
 
-const KZG_PROOF_BYTES_LEN: usize = 48;
-
 #[derive(PartialEq, Hash, Clone, Copy, Encode, Decode)]
 #[ssz(struct_behaviour = "transparent")]
-pub struct KzgProof(pub [u8; KZG_PROOF_BYTES_LEN]);
+pub struct KzgProof(pub [u8; BYTES_PER_PROOF]);
+
+impl From<KzgProof> for Bytes48 {
+    fn from(value: KzgProof) -> Self {
+        value.0.into()
+    }
+}
 
 impl KzgProof {
     pub fn empty() -> Self {
-        let mut bytes = [0; KZG_PROOF_BYTES_LEN];
+        let mut bytes = [0; BYTES_PER_PROOF];
         bytes[0] = 192;
         Self(bytes)
     }
@@ -28,33 +33,33 @@ impl fmt::Display for KzgProof {
 
 impl Default for KzgProof {
     fn default() -> Self {
-        KzgProof([0; KZG_PROOF_BYTES_LEN])
+        KzgProof([0; BYTES_PER_PROOF])
     }
 }
 
-impl From<[u8; KZG_PROOF_BYTES_LEN]> for KzgProof {
-    fn from(bytes: [u8; KZG_PROOF_BYTES_LEN]) -> Self {
+impl From<[u8; BYTES_PER_PROOF]> for KzgProof {
+    fn from(bytes: [u8; BYTES_PER_PROOF]) -> Self {
         Self(bytes)
     }
 }
 
-impl Into<[u8; KZG_PROOF_BYTES_LEN]> for KzgProof {
-    fn into(self) -> [u8; KZG_PROOF_BYTES_LEN] {
+impl Into<[u8; BYTES_PER_PROOF]> for KzgProof {
+    fn into(self) -> [u8; BYTES_PER_PROOF] {
         self.0
     }
 }
 
 impl TreeHash for KzgProof {
     fn tree_hash_type() -> tree_hash::TreeHashType {
-        <[u8; KZG_PROOF_BYTES_LEN]>::tree_hash_type()
+        <[u8; BYTES_PER_PROOF]>::tree_hash_type()
     }
 
     fn tree_hash_packed_encoding(&self) -> PackedEncoding {
         self.0.tree_hash_packed_encoding()
     }
 
     fn tree_hash_packing_factor() -> usize {
-        <[u8; KZG_PROOF_BYTES_LEN]>::tree_hash_packing_factor()
+        <[u8; BYTES_PER_PROOF]>::tree_hash_packing_factor()
     }
 
     fn tree_hash_root(&self) -> tree_hash::Hash256 {
@@ -104,15 +109,15 @@ impl FromStr for KzgProof {
     fn from_str(s: &str) -> Result<Self, Self::Err> {
         if let Some(stripped) = s.strip_prefix("0x") {
             let bytes = hex::decode(stripped).map_err(|e| e.to_string())?;
-            if bytes.len() == KZG_PROOF_BYTES_LEN {
-                let mut kzg_proof_bytes = [0; KZG_PROOF_BYTES_LEN];
+            if bytes.len() == BYTES_PER_PROOF {
+                let mut kzg_proof_bytes = [0; BYTES_PER_PROOF];
                 kzg_proof_bytes[..].copy_from_slice(&bytes);
                 Ok(Self(kzg_proof_bytes))
             } else {
                 Err(format!(
                     "InvalidByteLength: got {}, expected {}",
                     bytes.len(),
-                    KZG_PROOF_BYTES_LEN
+                    BYTES_PER_PROOF
                 ))
             }
         } else {
@@ -130,7 +135,7 @@ impl Debug for KzgProof {
 #[cfg(feature = "arbitrary")]
 impl arbitrary::Arbitrary<'_> for KzgProof {
     fn arbitrary(u: &mut arbitrary::Unstructured<'_>) -> arbitrary::Result<Self> {
-        let mut bytes = [0u8; KZG_PROOF_BYTES_LEN];
+        let mut bytes = [0u8; BYTES_PER_PROOF];
         u.fill_buffer(&mut bytes)?;
         Ok(KzgProof(bytes))
     }

crypto/kzg/src/lib.rs

@@ -3,6 +3,7 @@ mod kzg_proof;
 mod trusted_setup;
 
 pub use crate::{kzg_commitment::KzgCommitment, kzg_proof::KzgProof, trusted_setup::TrustedSetup};
+use c_kzg::Bytes48;
 pub use c_kzg::{
     Blob, Error as CKzgError, KZGSettings, BYTES_PER_BLOB, BYTES_PER_FIELD_ELEMENT,
     FIELD_ELEMENTS_PER_BLOB,
@@ -13,9 +14,9 @@ use std::path::PathBuf;
 pub enum Error {
     InvalidTrustedSetup(CKzgError),
     InvalidKzgProof(CKzgError),
-    InvalidLength(String),
+    InvalidBytes(CKzgError),
     KzgProofComputationFailed(CKzgError),
-    InvalidBlob(String),
+    InvalidBlob(CKzgError),
 }
 
 /// A wrapper over a kzg library that holds the trusted setup parameters.
@@ -51,40 +52,67 @@ impl Kzg {
         })
     }
 
-    /// Compute the aggregated kzg proof given an array of blobs.
-    pub fn compute_aggregate_kzg_proof(&self, blobs: &[Blob]) -> Result<KzgProof, Error> {
-        c_kzg::KZGProof::compute_aggregate_kzg_proof(blobs, &self.trusted_setup)
+    /// Compute the kzg proof given a blob and its kzg commitment.
+    pub fn compute_blob_kzg_proof(
+        &self,
+        blob: Blob,
+        kzg_commitment: KzgCommitment,
+    ) -> Result<KzgProof, Error> {
+        c_kzg::KZGProof::compute_blob_kzg_proof(blob, kzg_commitment.into(), &self.trusted_setup)
             .map_err(Error::KzgProofComputationFailed)
-            .map(|proof| KzgProof(proof.to_bytes()))
+            .map(|proof| KzgProof(proof.to_bytes().into_inner()))
     }
 
-    /// Verify an aggregate kzg proof given the blobs that generated the proof, the kzg commitments
-    /// and the kzg proof.
-    pub fn verify_aggregate_kzg_proof(
+    /// Verify a kzg proof given the blob, kzg commitment and kzg proof.
+    pub fn verify_blob_kzg_proof(
+        &self,
+        blob: Blob,
+        kzg_commitment: KzgCommitment,
+        kzg_proof: KzgProof,
+    ) -> Result<bool, Error> {
+        c_kzg::KZGProof::verify_blob_kzg_proof(
+            blob,
+            kzg_commitment.into(),
+            kzg_proof.into(),
+            &self.trusted_setup,
+        )
+        .map_err(Error::InvalidKzgProof)
+    }
+
+    /// Verify a batch of blob commitment proof triplets.
+    ///
+    /// Note: This method is slightly faster than calling `Self::verify_blob_kzg_proof` in a loop sequentially.
+    /// TODO(pawan): test performance against a parallelized rayon impl.
+    pub fn verify_blob_kzg_proof_batch(
         &self,
         blobs: &[Blob],
-        expected_kzg_commitments: &[KzgCommitment],
-        kzg_aggregated_proof: KzgProof,
+        kzg_commitments: &[KzgCommitment],
+        kzg_proofs: &[KzgProof],
     ) -> Result<bool, Error> {
-        if blobs.len() != expected_kzg_commitments.len() {
-            return Err(Error::InvalidLength(
-                "blobs and expected_kzg_commitments should be of same size".to_string(),
-            ));
-        }
-        let commitments = expected_kzg_commitments
+        let commitments_bytes = kzg_commitments
+            .iter()
+            .map(|comm| Bytes48::from_bytes(&comm.0))
+            .collect::<Result<Vec<Bytes48>, _>>()
+            .map_err(Error::InvalidBytes)?;
+
+        let proofs_bytes = kzg_proofs
             .iter()
-            .map(|comm| comm.0.into())
-            .collect::<Vec<c_kzg::KZGCommitment>>();
-        let proof: c_kzg::KZGProof = kzg_aggregated_proof.0.into();
-        proof
-            .verify_aggregate_kzg_proof(blobs, &commitments, &self.trusted_setup)
-            .map_err(Error::InvalidKzgProof)
+            .map(|proof| Bytes48::from_bytes(&proof.0))
+            .collect::<Result<Vec<Bytes48>, _>>()
+            .map_err(Error::InvalidBytes)?;
+        c_kzg::KZGProof::verify_blob_kzg_proof_batch(
+            blobs,
+            &commitments_bytes,
+            &proofs_bytes,
+            &self.trusted_setup,
+        )
+        .map_err(Error::InvalidKzgProof)
     }
 
     /// Converts a blob to a kzg commitment.
-    pub fn blob_to_kzg_commitment(&self, blob: Blob) -> KzgCommitment {
-        KzgCommitment(
-            c_kzg::KZGCommitment::blob_to_kzg_commitment(blob, &self.trusted_setup).to_bytes(),
-        )
+    pub fn blob_to_kzg_commitment(&self, blob: Blob) -> Result<KzgCommitment, Error> {
+        c_kzg::KZGCommitment::blob_to_kzg_commitment(blob, &self.trusted_setup)
+            .map_err(Error::InvalidBlob)
+            .map(|com| KzgCommitment(com.to_bytes().into_inner()))
     }
 }