Files
lighthouse/beacon_node/beacon_chain/src/kzg_utils.rs
Eitan Seri-Levi 027fdc1a68 Merge conflicts
2026-04-30 09:48:04 +02:00

1058 lines
40 KiB
Rust

use kzg::{
Cell as KzgCell, CellRef as KzgCellRef, CellsAndKzgProofs, Error as KzgError, Kzg, KzgBlobRef,
};
use rayon::prelude::*;
use ssz_types::{FixedVector, VariableList};
use std::sync::Arc;
use tracing::instrument;
use tree_hash::TreeHash;
use types::data::{
Cell, CellBitmap, ColumnIndex, DataColumn, DataColumnSidecarError, PartialDataColumn,
PartialDataColumnHeader, PartialDataColumnSidecarRef,
};
use types::kzg_ext::KzgCommitments;
use types::{
Blob, BlobSidecar, BlobSidecarList, ChainSpec, DataColumnSidecar, DataColumnSidecarFulu,
DataColumnSidecarGloas, DataColumnSidecarList, EthSpec, Hash256, KzgCommitment, KzgProof,
SignedBeaconBlock, SignedBeaconBlockHeader, SignedBlindedBeaconBlock, Slot,
};
/// Converts a blob ssz FixedVector to a reference to a fixed-size array
/// to be used with `rust_eth_kzg`.
fn ssz_blob_to_kzg_blob_ref<E: EthSpec>(blob: &Blob<E>) -> Result<KzgBlobRef<'_>, KzgError> {
blob.as_ref().try_into().map_err(|e| {
KzgError::InconsistentArrayLength(format!(
"blob should have a guaranteed size due to FixedVector: {e:?}"
))
})
}
/// Converts a cell ssz FixedVector to a reference to a fixed-size array
/// to be used with `rust_eth_kzg`.
fn ssz_cell_to_crypto_cell<E: EthSpec>(cell: &Cell<E>) -> Result<KzgCellRef<'_>, KzgError> {
let cell_bytes: &[u8] = cell.as_ref();
cell_bytes
.try_into()
.map_err(|e| KzgError::InconsistentArrayLength(format!("expected cell to have size BYTES_PER_CELL. This should be guaranteed by the `FixedVector` type: {e:?}")))
}
/// Validate a single blob-commitment-proof triplet from a `BlobSidecar`.
pub fn validate_blob<E: EthSpec>(
kzg: &Kzg,
blob: &Blob<E>,
kzg_commitment: KzgCommitment,
kzg_proof: KzgProof,
) -> Result<(), KzgError> {
let _timer = crate::metrics::start_timer(&crate::metrics::KZG_VERIFICATION_SINGLE_TIMES);
let kzg_blob = ssz_blob_to_kzg_blob_ref::<E>(blob)?;
kzg.verify_blob_kzg_proof(kzg_blob, kzg_commitment, kzg_proof)
}
/// Validate a batch of full `DataColumnSidecar`s.
///
/// Full columns have all cells present, so we iterate over all cells directly.
pub fn validate_full_data_columns<'a, E: EthSpec>(
kzg: &Kzg,
data_column_iter: impl Iterator<Item = &'a Arc<DataColumnSidecar<E>>>,
) -> Result<(), (Option<u64>, KzgError)> {
let mut cells = Vec::new();
let mut proofs = Vec::new();
let mut column_indices = Vec::new();
let mut commitments = Vec::new();
for data_column in data_column_iter {
let col_index = *data_column.index();
if data_column.column().is_empty() {
return Err((Some(col_index), KzgError::KzgVerificationFailed));
}
for cell in data_column.column() {
cells.push(ssz_cell_to_crypto_cell::<E>(cell).map_err(|e| (Some(col_index), e))?);
column_indices.push(col_index);
}
for &proof in data_column.kzg_proofs() {
proofs.push(proof.0);
}
// In Gloas, commitments come from the block's ExecutionPayloadBid, not the sidecar.
// This function requires Fulu sidecars with embedded commitments.
let kzg_commitments = match data_column.as_ref() {
DataColumnSidecar::Fulu(dc) => &dc.kzg_commitments,
DataColumnSidecar::Gloas(_) => {
return Err((
Some(col_index),
KzgError::InconsistentArrayLength(
"Gloas data columns require commitments from block".to_string(),
),
));
}
};
for &commitment in kzg_commitments.iter() {
commitments.push(commitment.0);
}
let expected_len = column_indices.len();
// We make this check at each iteration so that the error is attributable to a specific column
if cells.len() != expected_len
|| proofs.len() != expected_len
|| commitments.len() != expected_len
{
return Err((
Some(col_index),
KzgError::InconsistentArrayLength("Invalid data column".to_string()),
));
}
}
kzg.verify_cell_proof_batch(&cells, &proofs, column_indices, &commitments)
}
/// Validate a batch of partial `VerifiablePartialDataColumn`s.
///
/// Partial columns may have missing cells, indicated by a bitmap. We only verify present cells.
pub fn validate_partial_data_columns<'a, E: EthSpec>(
kzg: &Kzg,
data_column_iter: impl Iterator<Item = (ColumnIndex, PartialDataColumnSidecarRef<'a, E>)>,
kzg_commitments: &[KzgCommitment],
) -> Result<(), (Option<u64>, KzgError)> {
let mut cells = Vec::new();
let mut proofs = Vec::new();
let mut column_indices = Vec::new();
let mut commitments = Vec::new();
for (col_index, sidecar) in data_column_iter {
if sidecar.column.is_empty() {
return Err((Some(col_index), KzgError::KzgVerificationFailed));
}
// Partial columns have a bitmap indicating present cells
// We iterate over the bitmap and only process present cells
let mut present_iterator = sidecar.column.iter().zip(sidecar.kzg_proofs.iter());
for (present, commitment) in sidecar.cells_present_bitmap.iter().zip(kzg_commitments) {
if present {
let (cell, proof) = present_iterator.next().ok_or((
Some(col_index),
KzgError::InconsistentArrayLength(
"Partial column has fewer cells than bitmap indicates".to_string(),
),
))?;
cells.push(ssz_cell_to_crypto_cell::<E>(cell).map_err(|e| (Some(col_index), e))?);
column_indices.push(col_index);
proofs.push(proof.0);
commitments.push(commitment.0);
}
}
let expected_len = column_indices.len();
// We make this check at each iteration so that the error is attributable to a specific column
if cells.len() != expected_len
|| proofs.len() != expected_len
|| commitments.len() != expected_len
{
return Err((
Some(col_index),
KzgError::InconsistentArrayLength("Invalid data column".to_string()),
));
}
}
kzg.verify_cell_proof_batch(&cells, &proofs, column_indices, &commitments)
}
/// Validate a batch of blob-commitment-proof triplets from multiple `BlobSidecars`.
pub fn validate_blobs<E: EthSpec>(
kzg: &Kzg,
expected_kzg_commitments: &[KzgCommitment],
blobs: Vec<&Blob<E>>,
kzg_proofs: &[KzgProof],
) -> Result<(), KzgError> {
let _timer = crate::metrics::start_timer(&crate::metrics::KZG_VERIFICATION_BATCH_TIMES);
let blobs = blobs
.into_iter()
.map(|blob| ssz_blob_to_kzg_blob_ref::<E>(blob))
.collect::<Result<Vec<_>, KzgError>>()?;
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<E: EthSpec>(
kzg: &Kzg,
blob: &Blob<E>,
kzg_commitment: KzgCommitment,
) -> Result<KzgProof, KzgError> {
let kzg_blob = ssz_blob_to_kzg_blob_ref::<E>(blob)?;
kzg.compute_blob_kzg_proof(kzg_blob, kzg_commitment)
}
/// Compute the kzg commitment for a given blob.
pub fn blob_to_kzg_commitment<E: EthSpec>(
kzg: &Kzg,
blob: &Blob<E>,
) -> Result<KzgCommitment, KzgError> {
let kzg_blob = ssz_blob_to_kzg_blob_ref::<E>(blob)?;
kzg.blob_to_kzg_commitment(kzg_blob)
}
/// Compute the kzg proof for a given blob and an evaluation point z.
pub fn compute_kzg_proof<E: EthSpec>(
kzg: &Kzg,
blob: &Blob<E>,
z: Hash256,
) -> Result<(KzgProof, Hash256), KzgError> {
let kzg_blob = ssz_blob_to_kzg_blob_ref::<E>(blob)?;
kzg.compute_kzg_proof(kzg_blob, &z.0)
.map(|(proof, z)| (proof, Hash256::from_slice(&z)))
}
/// Verify a `kzg_proof` for a `kzg_commitment` that evaluating a polynomial at `z` results in `y`
pub fn verify_kzg_proof<E: EthSpec>(
kzg: &Kzg,
kzg_commitment: KzgCommitment,
kzg_proof: KzgProof,
z: Hash256,
y: Hash256,
) -> Result<bool, KzgError> {
kzg.verify_kzg_proof(kzg_commitment, &z.0, &y.0, kzg_proof)
}
/// Build data column sidecars from a signed beacon block and its blobs.
#[instrument(skip_all, level = "debug", fields(blob_count = blobs.len()))]
pub fn blobs_to_data_column_sidecars<E: EthSpec>(
blobs: &[&Blob<E>],
cell_proofs: Vec<KzgProof>,
block: &SignedBeaconBlock<E>,
kzg: &Kzg,
spec: &ChainSpec,
) -> Result<DataColumnSidecarList<E>, DataColumnSidecarError> {
if blobs.is_empty() {
return Ok(vec![]);
}
let kzg_commitments = block
.message()
.body()
.blob_kzg_commitments()
.map_err(|_err| DataColumnSidecarError::PreDeneb)?;
let signed_block_header = block.signed_block_header();
if cell_proofs.len() != blobs.len() * E::number_of_columns() {
return Err(DataColumnSidecarError::InvalidCellProofLength {
expected: blobs.len() * E::number_of_columns(),
actual: cell_proofs.len(),
});
}
let proof_chunks = cell_proofs
.chunks_exact(E::number_of_columns())
.collect::<Vec<_>>();
// NOTE: assumes blob sidecars are ordered by index
let zipped: Vec<_> = blobs.iter().zip(proof_chunks).collect();
let blob_cells_and_proofs_vec = zipped
.into_par_iter()
.map(|(blob, proofs)| {
let blob = blob.as_ref().try_into().map_err(|e| {
KzgError::InconsistentArrayLength(format!(
"blob should have a guaranteed size due to FixedVector: {e:?}"
))
})?;
kzg.compute_cells(blob).and_then(|cells| {
let proofs = proofs.try_into().map_err(|e| {
KzgError::InconsistentArrayLength(format!(
"proof chunks should have exactly `number_of_columns` proofs: {e:?}"
))
})?;
Ok((cells, proofs))
})
})
.collect::<Result<Vec<_>, KzgError>>()?;
if block.fork_name_unchecked().gloas_enabled() {
build_data_column_sidecars_gloas(
signed_block_header.message.tree_hash_root(),
block.slot(),
blob_cells_and_proofs_vec,
spec,
)
.map_err(DataColumnSidecarError::BuildSidecarFailed)
} else {
let kzg_commitments_inclusion_proof =
block.message().body().kzg_commitments_merkle_proof()?;
build_data_column_sidecars_fulu(
kzg_commitments.clone(),
kzg_commitments_inclusion_proof,
signed_block_header,
blob_cells_and_proofs_vec,
spec,
)
.map_err(DataColumnSidecarError::BuildSidecarFailed)
}
}
/// Build Gloas data column sidecars from blobs, computing cells and proofs locally.
pub fn blobs_to_data_column_sidecars_gloas<E: EthSpec>(
blobs: &[&Blob<E>],
beacon_block_root: Hash256,
slot: Slot,
kzg: &Kzg,
spec: &ChainSpec,
) -> Result<DataColumnSidecarList<E>, DataColumnSidecarError> {
if blobs.is_empty() {
return Ok(vec![]);
}
let blob_cells_and_proofs_vec = blobs
.into_par_iter()
.map(|blob| {
let blob = blob.as_ref().try_into().map_err(|e| {
KzgError::InconsistentArrayLength(format!(
"blob should have a guaranteed size due to FixedVector: {e:?}"
))
})?;
kzg.compute_cells_and_proofs(blob)
})
.collect::<Result<Vec<_>, KzgError>>()?;
build_data_column_sidecars_gloas(beacon_block_root, slot, blob_cells_and_proofs_vec, spec)
.map_err(DataColumnSidecarError::BuildSidecarFailed)
}
/// Build data column sidecars from a signed beacon block and its blobs.
#[instrument(skip_all, level = "debug", fields(blob_count = blobs_and_proofs.len()))]
pub fn blobs_to_partial_data_columns<E: EthSpec>(
blobs_and_proofs: Vec<Option<(&Blob<E>, &[KzgProof])>>,
header: &PartialDataColumnHeader<E>,
kzg: &Kzg,
spec: &ChainSpec,
) -> Result<Vec<PartialDataColumn<E>>, DataColumnSidecarError> {
if blobs_and_proofs.is_empty() {
return Ok(vec![]);
}
let blob_cells_and_proofs_vec = blobs_and_proofs
.into_par_iter()
.map(|maybe_blob_and_proofs| {
let Some((blob, proofs)) = maybe_blob_and_proofs else {
return Ok(None);
};
let blob = blob.as_ref().try_into().map_err(|e| {
KzgError::InconsistentArrayLength(format!(
"blob should have a guaranteed size due to FixedVector: {e:?}"
))
})?;
kzg.compute_cells(blob).and_then(|cells| {
let proofs = proofs.try_into().map_err(|e| {
KzgError::InconsistentArrayLength(format!(
"proof chunks should have exactly `number_of_columns` proofs: {e:?}"
))
})?;
Ok(Some((cells, proofs)))
})
})
.collect::<Result<Vec<_>, KzgError>>()?;
build_partial_data_columns(header, blob_cells_and_proofs_vec, spec)
.map_err(DataColumnSidecarError::BuildSidecarFailed)
}
pub fn compute_cells<E: EthSpec>(blobs: &[&Blob<E>], kzg: &Kzg) -> Result<Vec<KzgCell>, KzgError> {
let cells_vec = blobs
.into_par_iter()
.map(|blob| {
let blob: KzgBlobRef<'_> = blob.as_ref().try_into().map_err(|e| {
KzgError::InconsistentArrayLength(format!(
"blob should have a guaranteed size due to FixedVector: {e:?}",
))
})?;
kzg.compute_cells(blob)
})
.collect::<Result<Vec<_>, KzgError>>()?;
let cells_flattened: Vec<KzgCell> = cells_vec.into_iter().flatten().collect();
Ok(cells_flattened)
}
pub(crate) fn build_data_column_sidecars_fulu<E: EthSpec>(
kzg_commitments: KzgCommitments<E>,
kzg_commitments_inclusion_proof: FixedVector<Hash256, E::KzgCommitmentsInclusionProofDepth>,
signed_block_header: SignedBeaconBlockHeader,
blob_cells_and_proofs_vec: Vec<CellsAndKzgProofs>,
spec: &ChainSpec,
) -> Result<DataColumnSidecarList<E>, String> {
if spec
.fork_name_at_slot::<E>(signed_block_header.message.slot)
.gloas_enabled()
{
return Err("Attempting to construct Fulu data columns post-Gloas".to_owned());
}
let number_of_columns = E::number_of_columns();
let max_blobs_per_block = spec
.max_blobs_per_block(signed_block_header.message.slot.epoch(E::slots_per_epoch()))
as usize;
let mut columns = vec![Vec::with_capacity(max_blobs_per_block); number_of_columns];
let mut column_kzg_proofs = vec![Vec::with_capacity(max_blobs_per_block); number_of_columns];
for (blob_cells, blob_cell_proofs) in blob_cells_and_proofs_vec {
// we iterate over each column, and we construct the column from "top to bottom",
// pushing on the cell and the corresponding proof at each column index. we do this for
// each blob (i.e. the outer loop).
for col in 0..number_of_columns {
let cell = blob_cells
.get(col)
.ok_or(format!("Missing blob cell at index {col}"))?;
let cell: Vec<u8> = cell.to_vec();
let cell =
Cell::<E>::try_from(cell).map_err(|e| format!("BytesPerCell exceeded: {e:?}"))?;
let proof = blob_cell_proofs
.get(col)
.ok_or(format!("Missing blob cell KZG proof at index {col}"))?;
let column = columns
.get_mut(col)
.ok_or(format!("Missing data column at index {col}"))?;
let column_proofs = column_kzg_proofs
.get_mut(col)
.ok_or(format!("Missing data column proofs at index {col}"))?;
column.push(cell);
column_proofs.push(*proof);
}
}
let sidecars: Result<Vec<Arc<DataColumnSidecar<E>>>, String> = columns
.into_iter()
.zip(column_kzg_proofs)
.enumerate()
.map(
|(index, (col, proofs))| -> Result<Arc<DataColumnSidecar<E>>, String> {
Ok(Arc::new(DataColumnSidecar::Fulu(DataColumnSidecarFulu {
index: index as u64,
column: DataColumn::<E>::try_from(col)
.map_err(|e| format!("MaxBlobCommitmentsPerBlock exceeded: {e:?}"))?,
kzg_commitments: kzg_commitments.clone(),
kzg_proofs: VariableList::try_from(proofs)
.map_err(|e| format!("MaxBlobCommitmentsPerBlock exceeded: {e:?}"))?,
signed_block_header: signed_block_header.clone(),
kzg_commitments_inclusion_proof: kzg_commitments_inclusion_proof.clone(),
})))
},
)
.collect();
sidecars
}
pub(crate) fn build_data_column_sidecars_gloas<E: EthSpec>(
beacon_block_root: Hash256,
slot: Slot,
blob_cells_and_proofs_vec: Vec<CellsAndKzgProofs>,
spec: &ChainSpec,
) -> Result<DataColumnSidecarList<E>, String> {
if !spec.fork_name_at_slot::<E>(slot).gloas_enabled() {
return Err("Attempting to construct Gloas data columns pre-Gloas".to_owned());
}
let number_of_columns = E::number_of_columns();
let max_blobs_per_block = spec.max_blobs_per_block(slot.epoch(E::slots_per_epoch())) as usize;
let mut columns = vec![Vec::with_capacity(max_blobs_per_block); number_of_columns];
let mut column_kzg_proofs = vec![Vec::with_capacity(max_blobs_per_block); number_of_columns];
for (blob_cells, blob_cell_proofs) in blob_cells_and_proofs_vec {
// we iterate over each column, and we construct the column from "top to bottom",
// pushing on the cell and the corresponding proof at each column index. we do this for
// each blob (i.e. the outer loop).
for col in 0..number_of_columns {
let cell = blob_cells
.get(col)
.ok_or(format!("Missing blob cell at index {col}"))?;
let cell: Vec<u8> = cell.to_vec();
let cell =
Cell::<E>::try_from(cell).map_err(|e| format!("BytesPerCell exceeded: {e:?}"))?;
let proof = blob_cell_proofs
.get(col)
.ok_or(format!("Missing blob cell KZG proof at index {col}"))?;
let column = columns
.get_mut(col)
.ok_or(format!("Missing data column at index {col}"))?;
let column_proofs = column_kzg_proofs
.get_mut(col)
.ok_or(format!("Missing data column proofs at index {col}"))?;
column.push(cell);
column_proofs.push(*proof);
}
}
let sidecars: Result<Vec<Arc<DataColumnSidecar<E>>>, String> = columns
.into_iter()
.zip(column_kzg_proofs)
.enumerate()
.map(
|(index, (col, proofs))| -> Result<Arc<DataColumnSidecar<E>>, String> {
Ok(Arc::new(DataColumnSidecar::Gloas(DataColumnSidecarGloas {
index: index as u64,
column: DataColumn::<E>::try_from(col)
.map_err(|e| format!("MaxBlobCommitmentsPerBlock exceeded: {e:?}"))?,
kzg_proofs: VariableList::try_from(proofs)
.map_err(|e| format!("MaxBlobCommitmentsPerBlock exceeded: {e:?}"))?,
beacon_block_root,
slot,
})))
},
)
.collect();
sidecars
}
pub(crate) fn build_partial_data_columns<E: EthSpec>(
header: &PartialDataColumnHeader<E>,
blob_cells_and_proofs_vec: Vec<Option<CellsAndKzgProofs>>,
spec: &ChainSpec,
) -> Result<Vec<PartialDataColumn<E>>, String> {
let number_of_columns = E::number_of_columns();
let max_blobs_per_block =
spec.max_blobs_per_block(header.slot().epoch(E::slots_per_epoch())) as usize;
let mut bitmap =
CellBitmap::<E>::with_capacity(blob_cells_and_proofs_vec.len()).map_err(|_| {
format!(
"Exceeded max committment count: {} (got {})",
E::max_blob_commitments_per_block(),
blob_cells_and_proofs_vec.len()
)
})?;
let mut columns = vec![Vec::with_capacity(max_blobs_per_block); number_of_columns];
let mut column_kzg_proofs = vec![Vec::with_capacity(max_blobs_per_block); number_of_columns];
for (idx, maybe_cells_and_proofs) in blob_cells_and_proofs_vec.into_iter().enumerate() {
let Some((blob_cells, blob_cell_proofs)) = maybe_cells_and_proofs else {
continue;
};
bitmap
.set(idx, true)
.expect("bitmap constructed from iterator length above");
// we iterate over each column, and we construct the column from "top to bottom",
// pushing on the cell and the corresponding proof at each column index. we do this for
// each blob (i.e. the outer loop).
for col in 0..number_of_columns {
let cell = blob_cells
.get(col)
.ok_or(format!("Missing blob cell at index {col}"))?;
let cell: Vec<u8> = cell.to_vec();
let cell =
Cell::<E>::try_from(cell).map_err(|e| format!("BytesPerCell exceeded: {e:?}"))?;
let proof = blob_cell_proofs
.get(col)
.ok_or(format!("Missing blob cell KZG proof at index {col}"))?;
let column = columns
.get_mut(col)
.ok_or(format!("Missing data column at index {col}"))?;
let column_proofs = column_kzg_proofs
.get_mut(col)
.ok_or(format!("Missing data column proofs at index {col}"))?;
column.push(cell);
column_proofs.push(*proof);
}
}
let block_root = header.signed_block_header.message.canonical_root();
let sidecars: Result<Vec<PartialDataColumn<E>>, String> = columns
.into_iter()
.zip(column_kzg_proofs)
.enumerate()
.map(|(index, (col, proofs))| {
let column = PartialDataColumn {
block_root,
index: index as u64,
sidecar: types::data::PartialDataColumnSidecar {
cells_present_bitmap: bitmap.clone(),
column: VariableList::try_from(col)
.map_err(|e| format!("MaxBlobCommitmentsPerBlock exceeded: {e:?}"))?,
kzg_proofs: VariableList::try_from(proofs)
.map_err(|e| format!("MaxBlobCommitmentsPerBlock exceeded: {e:?}"))?,
header: None.into(),
},
};
Ok(column)
})
.collect();
sidecars
}
// TODO(gloas) blob reconstruction will fail post gloas. We should just return `Blob`s
// instead of a `BlobSidecar`. This might require a beacon api spec change as well.
/// Reconstruct blobs from a subset of data column sidecars (requires at least 50%).
///
/// If `blob_indices_opt` is `None`, this function attempts to reconstruct all blobs associated
/// with the block.
/// This function does NOT use rayon as this is primarily used by a non critical path in HTTP API
/// and it will be slow if the node needs to reconstruct the blobs
pub fn reconstruct_blobs<E: EthSpec>(
kzg: &Kzg,
mut data_columns: Vec<Arc<DataColumnSidecar<E>>>,
blob_indices_opt: Option<Vec<u64>>,
signed_block: &SignedBlindedBeaconBlock<E>,
spec: &ChainSpec,
) -> Result<BlobSidecarList<E>, String> {
// Sort data columns by index to ensure ascending order for KZG operations
data_columns.sort_unstable_by_key(|dc| *dc.index());
let first_data_column = data_columns
.first()
.ok_or("data_columns should have at least one element".to_string())?;
let blob_indices: Vec<usize> = match blob_indices_opt {
Some(indices) => indices.into_iter().map(|i| i as usize).collect(),
None => {
// TODO(gloas): support blob reconstruction for Gloas
// https://github.com/sigp/lighthouse/issues/7413
let num_of_blobs = first_data_column
.kzg_commitments()
.map_err(|_| "Gloas blob reconstruction not yet supported".to_string())?
.len();
(0..num_of_blobs).collect()
}
};
let blob_sidecars = blob_indices
.into_iter()
.map(|row_index| {
let mut cells: Vec<KzgCellRef> = vec![];
let mut cell_ids: Vec<u64> = vec![];
for data_column in &data_columns {
let cell = data_column
.column()
.get(row_index)
.ok_or(format!("Missing data column at row index {row_index}"))
.and_then(|cell| {
ssz_cell_to_crypto_cell::<E>(cell).map_err(|e| format!("{e:?}"))
})?;
cells.push(cell);
cell_ids.push(*data_column.index());
}
let num_cells_original_blob = E::number_of_columns() / 2;
let blob_bytes = if data_columns.len() < E::number_of_columns() {
let (recovered_cells, _kzg_proofs) = kzg
.recover_cells_and_compute_kzg_proofs(&cell_ids, &cells)
.map_err(|e| {
format!("Failed to recover cells and compute KZG proofs: {e:?}")
})?;
recovered_cells
.into_iter()
.take(num_cells_original_blob)
.flat_map(|cell| cell.into_iter())
.collect()
} else {
cells
.into_iter()
.take(num_cells_original_blob)
.flat_map(|cell| (*cell).into_iter())
.collect()
};
let blob = Blob::<E>::new(blob_bytes).map_err(|e| format!("{e:?}"))?;
let kzg_proof = KzgProof::empty();
BlobSidecar::<E>::new_with_existing_proof(row_index, blob, signed_block, kzg_proof)
.map(Arc::new)
.map_err(|e| format!("{e:?}"))
})
.collect::<Result<Vec<_>, _>>()?;
let max_blobs = spec.max_blobs_per_block(signed_block.epoch()) as usize;
BlobSidecarList::new(blob_sidecars, max_blobs).map_err(|e| format!("{e:?}"))
}
/// Reconstruct all data columns from a subset of data column sidecars (requires at least 50%).
pub fn reconstruct_data_columns<E: EthSpec>(
kzg: &Kzg,
mut data_columns: Vec<Arc<DataColumnSidecar<E>>>,
spec: &ChainSpec,
) -> Result<DataColumnSidecarList<E>, KzgError> {
// Sort data columns by index to ensure ascending order for KZG operations
data_columns.sort_unstable_by_key(|dc| *dc.index());
let first_data_column = data_columns
.first()
.ok_or(KzgError::InconsistentArrayLength(
"data_columns should have at least one element".to_string(),
))?;
// TODO(gloas): support data column reconstruction for Gloas
// https://github.com/sigp/lighthouse/issues/7413
let num_of_blobs = first_data_column
.kzg_commitments()
.map_err(|_| {
KzgError::InconsistentArrayLength(
"Gloas data column reconstruction not yet supported".to_string(),
)
})?
.len();
let blob_cells_and_proofs_vec = (0..num_of_blobs)
.into_par_iter()
.map(|row_index| {
let mut cells: Vec<KzgCellRef> = vec![];
let mut cell_ids: Vec<u64> = vec![];
for data_column in &data_columns {
let cell = data_column.column().get(row_index).ok_or(
KzgError::InconsistentArrayLength(format!(
"Missing data column at row index {row_index}"
)),
)?;
cells.push(ssz_cell_to_crypto_cell::<E>(cell)?);
cell_ids.push(*data_column.index());
}
kzg.recover_cells_and_compute_kzg_proofs(&cell_ids, &cells)
})
.collect::<Result<Vec<_>, KzgError>>()?;
match first_data_column.as_ref() {
DataColumnSidecar::Fulu(first_column) => {
// Clone sidecar elements from existing data column, no need to re-compute
build_data_column_sidecars_fulu(
first_column.kzg_commitments.clone(),
first_column.kzg_commitments_inclusion_proof.clone(),
first_column.signed_block_header.clone(),
blob_cells_and_proofs_vec,
spec,
)
.map_err(KzgError::ReconstructFailed)
}
DataColumnSidecar::Gloas(first_column) => build_data_column_sidecars_gloas(
first_column.beacon_block_root,
first_column.slot,
blob_cells_and_proofs_vec,
spec,
)
.map_err(KzgError::ReconstructFailed),
}
}
#[cfg(test)]
mod test {
use crate::kzg_utils::{
blobs_to_data_column_sidecars, blobs_to_data_column_sidecars_gloas, reconstruct_blobs,
reconstruct_data_columns, validate_full_data_columns,
};
use bls::Signature;
use eth2::types::BlobsBundle;
use execution_layer::test_utils::generate_blobs;
use kzg::{Kzg, KzgCommitment, trusted_setup::get_trusted_setup};
use types::{
BeaconBlock, BeaconBlockFulu, BlobsList, ChainSpec, EmptyBlock, EthSpec, ForkName,
FullPayload, Hash256, KzgProofs, MainnetEthSpec, SignedBeaconBlock, Slot,
kzg_ext::KzgCommitments,
};
type E = MainnetEthSpec;
// Loading and initializing PeerDAS KZG is expensive and slow, so we group the tests together
// only load it once.
#[test]
fn test_build_data_columns_sidecars() {
let kzg = get_kzg();
let fulu_spec = ForkName::Fulu.make_genesis_spec(E::default_spec());
test_build_data_columns_empty(&kzg, &fulu_spec);
test_build_data_columns_fulu(&kzg, &fulu_spec);
test_reconstruct_data_columns(&kzg, &fulu_spec);
test_reconstruct_data_columns_unordered(&kzg, &fulu_spec);
test_reconstruct_blobs_from_data_columns(&kzg, &fulu_spec);
test_reconstruct_blobs_from_data_columns_unordered(&kzg, &fulu_spec);
test_validate_data_columns(&kzg, &fulu_spec);
let gloas_spec = ForkName::Gloas.make_genesis_spec(E::default_spec());
test_build_data_columns_gloas(&kzg, &gloas_spec);
test_build_data_columns_gloas_empty(&kzg, &gloas_spec);
}
#[track_caller]
fn test_validate_data_columns(kzg: &Kzg, spec: &ChainSpec) {
let num_of_blobs = 2;
let (signed_block, blobs, proofs) =
create_test_fulu_block_and_blobs::<E>(num_of_blobs, spec);
let blob_refs = blobs.iter().collect::<Vec<_>>();
let column_sidecars =
blobs_to_data_column_sidecars(&blob_refs, proofs.to_vec(), &signed_block, kzg, spec)
.unwrap();
let result = validate_full_data_columns(kzg, column_sidecars.iter());
assert!(result.is_ok());
}
#[track_caller]
fn test_build_data_columns_empty(kzg: &Kzg, spec: &ChainSpec) {
let num_of_blobs = 0;
let (signed_block, blobs, proofs) =
create_test_fulu_block_and_blobs::<E>(num_of_blobs, spec);
let blob_refs = blobs.iter().collect::<Vec<_>>();
let column_sidecars =
blobs_to_data_column_sidecars(&blob_refs, proofs.to_vec(), &signed_block, kzg, spec)
.unwrap();
assert!(column_sidecars.is_empty());
}
#[track_caller]
fn test_build_data_columns_gloas(kzg: &Kzg, spec: &ChainSpec) {
let num_of_blobs = 2;
let (blobs, _proofs) = create_test_gloas_blobs::<E>(num_of_blobs);
let beacon_block_root = Hash256::random();
let slot = Slot::new(0);
let blob_refs: Vec<_> = blobs.iter().collect();
let column_sidecars = blobs_to_data_column_sidecars_gloas::<E>(
&blob_refs,
beacon_block_root,
slot,
kzg,
spec,
)
.unwrap();
assert_eq!(column_sidecars.len(), E::number_of_columns());
for (idx, col_sidecar) in column_sidecars.iter().enumerate() {
assert_eq!(*col_sidecar.index(), idx as u64);
assert_eq!(col_sidecar.column().len(), num_of_blobs);
assert_eq!(col_sidecar.kzg_proofs().len(), num_of_blobs);
let gloas_col = col_sidecar.as_gloas().expect("should be Gloas sidecar");
assert_eq!(gloas_col.beacon_block_root, beacon_block_root);
assert_eq!(gloas_col.slot, slot);
}
}
#[track_caller]
fn test_build_data_columns_gloas_empty(kzg: &Kzg, spec: &ChainSpec) {
let blob_refs: Vec<&types::Blob<E>> = vec![];
let column_sidecars = blobs_to_data_column_sidecars_gloas::<E>(
&blob_refs,
Hash256::random(),
Slot::new(0),
kzg,
spec,
)
.unwrap();
assert!(column_sidecars.is_empty());
}
#[track_caller]
fn test_build_data_columns_fulu(kzg: &Kzg, spec: &ChainSpec) {
// Using at least 2 blobs to make sure we're arranging the data columns correctly.
let num_of_blobs = 2;
let (signed_block, blobs, proofs) =
create_test_fulu_block_and_blobs::<E>(num_of_blobs, spec);
let blob_refs = blobs.iter().collect::<Vec<_>>();
let column_sidecars =
blobs_to_data_column_sidecars(&blob_refs, proofs.to_vec(), &signed_block, kzg, spec)
.unwrap();
let block_kzg_commitments = signed_block
.message()
.body()
.blob_kzg_commitments()
.unwrap()
.clone();
let block_kzg_commitments_inclusion_proof = signed_block
.message()
.body()
.kzg_commitments_merkle_proof()
.unwrap();
assert_eq!(column_sidecars.len(), E::number_of_columns());
for (idx, col_sidecar) in column_sidecars.iter().enumerate() {
assert_eq!(*col_sidecar.index(), idx as u64);
assert_eq!(col_sidecar.kzg_commitments().unwrap().len(), num_of_blobs);
assert_eq!(col_sidecar.column().len(), num_of_blobs);
assert_eq!(col_sidecar.kzg_proofs().len(), num_of_blobs);
assert_eq!(
col_sidecar.kzg_commitments().unwrap().clone(),
block_kzg_commitments
);
assert_eq!(
col_sidecar
.kzg_commitments_inclusion_proof()
.unwrap()
.clone(),
block_kzg_commitments_inclusion_proof
);
assert!(col_sidecar.as_fulu().unwrap().verify_inclusion_proof());
}
}
#[track_caller]
fn test_reconstruct_data_columns(kzg: &Kzg, spec: &ChainSpec) {
// Using at least 2 blobs to make sure we're arranging the data columns correctly.
let num_of_blobs = 2;
let (signed_block, blobs, proofs) =
create_test_fulu_block_and_blobs::<E>(num_of_blobs, spec);
let blob_refs = blobs.iter().collect::<Vec<_>>();
let column_sidecars =
blobs_to_data_column_sidecars(&blob_refs, proofs.to_vec(), &signed_block, kzg, spec)
.unwrap();
// Now reconstruct
let reconstructed_columns = reconstruct_data_columns(
kzg,
column_sidecars.iter().as_slice()[0..column_sidecars.len() / 2].to_vec(),
spec,
)
.unwrap();
for i in 0..E::number_of_columns() {
assert_eq!(reconstructed_columns.get(i), column_sidecars.get(i), "{i}");
}
}
#[track_caller]
fn test_reconstruct_data_columns_unordered(kzg: &Kzg, spec: &ChainSpec) {
// Using at least 2 blobs to make sure we're arranging the data columns correctly.
let num_of_blobs = 2;
let (signed_block, blobs, proofs) =
create_test_fulu_block_and_blobs::<E>(num_of_blobs, spec);
let blob_refs = blobs.iter().collect::<Vec<_>>();
let column_sidecars =
blobs_to_data_column_sidecars(&blob_refs, proofs.to_vec(), &signed_block, kzg, spec)
.unwrap();
// Test reconstruction with columns in reverse order (non-ascending)
let mut subset_columns: Vec<_> =
column_sidecars.iter().as_slice()[0..column_sidecars.len() / 2].to_vec();
subset_columns.reverse(); // This would fail without proper sorting in reconstruct_data_columns
let reconstructed_columns = reconstruct_data_columns(kzg, subset_columns, spec).unwrap();
for i in 0..E::number_of_columns() {
assert_eq!(reconstructed_columns.get(i), column_sidecars.get(i), "{i}");
}
}
#[track_caller]
fn test_reconstruct_blobs_from_data_columns(kzg: &Kzg, spec: &ChainSpec) {
let num_of_blobs = 3;
let (signed_block, blobs, proofs) =
create_test_fulu_block_and_blobs::<E>(num_of_blobs, spec);
let blob_refs = blobs.iter().collect::<Vec<_>>();
let column_sidecars =
blobs_to_data_column_sidecars(&blob_refs, proofs.to_vec(), &signed_block, kzg, spec)
.unwrap();
// Now reconstruct
let signed_blinded_block = signed_block.into();
// Using at least 2 blobs to make sure we're arranging the data columns correctly.
let blob_indices = vec![1, 2];
let reconstructed_blobs = reconstruct_blobs(
kzg,
column_sidecars[0..column_sidecars.len() / 2].to_vec(),
Some(blob_indices.clone()),
&signed_blinded_block,
spec,
)
.unwrap();
for i in blob_indices {
let reconstructed_blob = &reconstructed_blobs
.iter()
.find(|sidecar| sidecar.index == i)
.map(|sidecar| sidecar.blob.clone())
.expect("reconstructed blob should exist");
let original_blob = blobs.get(i as usize).unwrap();
assert_eq!(reconstructed_blob, original_blob, "{i}");
}
}
#[track_caller]
fn test_reconstruct_blobs_from_data_columns_unordered(kzg: &Kzg, spec: &ChainSpec) {
let num_of_blobs = 2;
let (signed_block, blobs, proofs) =
create_test_fulu_block_and_blobs::<E>(num_of_blobs, spec);
let blob_refs = blobs.iter().collect::<Vec<_>>();
let column_sidecars =
blobs_to_data_column_sidecars(&blob_refs, proofs.to_vec(), &signed_block, kzg, spec)
.unwrap();
// Test reconstruction with columns in reverse order (non-ascending)
let mut subset_columns: Vec<_> =
column_sidecars.iter().as_slice()[0..column_sidecars.len() / 2].to_vec();
subset_columns.reverse(); // This would fail without proper sorting in reconstruct_blobs
let signed_blinded_block = signed_block.into();
let reconstructed_blobs =
reconstruct_blobs(kzg, subset_columns, None, &signed_blinded_block, spec).unwrap();
for (i, original_blob) in blobs.iter().enumerate() {
let reconstructed_blob = &reconstructed_blobs.get(i).unwrap().blob;
assert_eq!(reconstructed_blob, original_blob, "{i}");
}
}
fn get_kzg() -> Kzg {
Kzg::new_from_trusted_setup(&get_trusted_setup()).expect("should create kzg")
}
fn create_test_fulu_block_and_blobs<E: EthSpec>(
num_of_blobs: usize,
spec: &ChainSpec,
) -> (
SignedBeaconBlock<E, FullPayload<E>>,
BlobsList<E>,
KzgProofs<E>,
) {
let mut block = BeaconBlock::Fulu(BeaconBlockFulu::empty(spec));
let mut body = block.body_mut();
let blob_kzg_commitments = body.blob_kzg_commitments_mut().unwrap();
*blob_kzg_commitments =
KzgCommitments::<E>::new(vec![KzgCommitment::empty_for_testing(); num_of_blobs])
.unwrap();
let mut signed_block = SignedBeaconBlock::from_block(block, Signature::empty());
let fork = signed_block.fork_name_unchecked();
let (blobs_bundle, _) = generate_blobs::<E>(num_of_blobs, fork).unwrap();
let BlobsBundle {
blobs,
commitments,
proofs,
} = blobs_bundle;
*signed_block
.message_mut()
.body_mut()
.blob_kzg_commitments_mut()
.unwrap() = commitments;
(signed_block, blobs, proofs)
}
fn create_test_gloas_blobs<E: EthSpec>(num_of_blobs: usize) -> (BlobsList<E>, KzgProofs<E>) {
let (blobs_bundle, _) = generate_blobs::<E>(num_of_blobs, ForkName::Gloas).unwrap();
(blobs_bundle.blobs, blobs_bundle.proofs)
}
}