/// <summary>
/// Check if ``indexed_attestation`` has valid indices and signature.
/// </summary>
public bool IsValidIndexedAttestation(BeaconState state, IndexedAttestation indexedAttestation, Domain domain)
{
MiscellaneousParameters miscellaneousParameters = _miscellaneousParameterOptions.CurrentValue;
IList <ValidatorIndex> bit0Indices = indexedAttestation.CustodyBit0Indices;
IList <ValidatorIndex> bit1Indices = indexedAttestation.CustodyBit1Indices;
// Verify no index has custody bit equal to 1 [to be removed in phase 1]
if (bit1Indices.Count != 0) // [to be removed in phase 1]
{
if (_logger.IsWarn())
{
_logger.LogWarning(Event.InvalidIndexedAttestation,
"Invalid indexed attestion from committee {CommitteeIndex} for slot {Slot}, because it has {BitIndicesCount} bit 1 indices.",
indexedAttestation.Data.Index, indexedAttestation.Data.Slot, bit1Indices.Count());
}
return(false); //[to be removed in phase 1]
}
// Verify max number of indices
int totalIndices = bit0Indices.Count + bit1Indices.Count;
if ((ulong)totalIndices > miscellaneousParameters.MaximumValidatorsPerCommittee)
{
if (_logger.IsWarn())
{
_logger.LogWarning(Event.InvalidIndexedAttestation,
"Invalid indexed attestion from committee {CommitteeIndex} for slot {Slot}, because it has total indices {TotalIndices}, more than the maximum validators per committe {MaximumValidatorsPerCommittee}.",
indexedAttestation.Data.Index, indexedAttestation.Data.Slot, totalIndices, miscellaneousParameters.MaximumValidatorsPerCommittee);
}
return(false);
}
// Verify index sets are disjoint
IEnumerable <ValidatorIndex> intersect = bit0Indices.Intersect(bit1Indices);
if (intersect.Count() != 0)
{
if (_logger.IsWarn())
{
_logger.LogWarning(Event.InvalidIndexedAttestation,
"Invalid indexed attestion from committee {CommitteeIndex} for slot {Slot}, because it has {IntersectingValidatorCount} validator indexes in common between custody bit 0 and custody bit 1.",
indexedAttestation.Data.Index, indexedAttestation.Data.Slot, intersect.Count());
}
return(false);
}
// Verify indices are sorted
if (bit0Indices.Count() > 1)
{
for (int index = 0; index < bit0Indices.Count() - 1; index++)
{
if (!(bit0Indices[index] < bit0Indices[index + 1]))
{
if (_logger.IsWarn())
{
_logger.LogWarning(Event.InvalidIndexedAttestation,
"Invalid indexed attestion from committee {CommitteeIndex} for slot {Slot}, because custody bit 0 index {IndexNumber} is not sorted.",
indexedAttestation.Data.Index, indexedAttestation.Data.Slot, index);
}
return(false);
}
}
}
if (bit1Indices.Count() > 1)
{
for (int index = 0; index < bit1Indices.Count() - 1; index++)
{
if (!(bit1Indices[index] < bit1Indices[index + 1]))
{
if (_logger.IsWarn())
{
_logger.LogWarning(Event.InvalidIndexedAttestation,
"Invalid indexed attestion from committee {CommitteeIndex} for slot {Slot}, because custody bit 1 index {IndexNumber} is not sorted.",
indexedAttestation.Data.Index, indexedAttestation.Data.Slot, index);
}
return(false);
}
}
}
// Verify aggregate signature
IEnumerable <BlsPublicKey> bit0PublicKeys = bit0Indices.Select(x => state.Validators[(int)(ulong)x].PublicKey);
BlsPublicKey bit0AggregatePublicKey = _cryptographyService.BlsAggregatePublicKeys(bit0PublicKeys);
IEnumerable <BlsPublicKey> bit1PublicKeys = bit1Indices.Select(x => state.Validators[(int)(ulong)x].PublicKey);
BlsPublicKey bit1AggregatePublicKey = _cryptographyService.BlsAggregatePublicKeys(bit1PublicKeys);
BlsPublicKey[] publicKeys = new[] { bit0AggregatePublicKey, bit1AggregatePublicKey };
AttestationDataAndCustodyBit attestationDataAndCustodyBit0 = new AttestationDataAndCustodyBit(indexedAttestation.Data, false);
Hash32 messageHashBit0 = attestationDataAndCustodyBit0.HashTreeRoot();
AttestationDataAndCustodyBit attestationDataAndCustodyBit1 = new AttestationDataAndCustodyBit(indexedAttestation.Data, true);
Hash32 messageHashBit1 = attestationDataAndCustodyBit1.HashTreeRoot();
Hash32[] messageHashes = new[] { messageHashBit0, messageHashBit1 };
BlsSignature signature = indexedAttestation.Signature;
bool isValid = _cryptographyService.BlsVerifyMultiple(publicKeys, messageHashes, signature, domain);
if (!isValid)
{
if (_logger.IsWarn())
{
_logger.LogWarning(Event.InvalidIndexedAttestation,
"Invalid indexed attestion from committee {CommitteeIndex} for slot {Slot}, because the aggregate signature does not match.",
indexedAttestation.Data.Index, indexedAttestation.Data.Slot);
}
return(false);
}
return(true);
}