diff --git a/crypto/kzg4844/kzg4844.go b/crypto/kzg4844/kzg4844.go index 5969d1c2cee10..4561ef9de95b3 100644 --- a/crypto/kzg4844/kzg4844.go +++ b/crypto/kzg4844/kzg4844.go @@ -20,6 +20,7 @@ package kzg4844 import ( "embed" "errors" + "hash" "sync/atomic" ) @@ -108,3 +109,21 @@ func VerifyBlobProof(blob Blob, commitment Commitment, proof Proof) error { } return gokzgVerifyBlobProof(blob, commitment, proof) } + +// CalcBlobHashV1 calculates the 'versioned blob hash' of a commitment. +// The given hasher must be a sha256 hash instance, otherwise the result will be invalid! +func CalcBlobHashV1(hasher hash.Hash, commit *Commitment) (vh [32]byte) { + if hasher.Size() != 32 { + panic("wrong hash size") + } + hasher.Reset() + hasher.Write(commit[:]) + hasher.Sum(vh[:0]) + vh[0] = 0x01 // version + return vh +} + +// IsValidVersionedHash checks that h is a structurally-valid versioned blob hash. +func IsValidVersionedHash(h []byte) bool { + return len(h) == 32 && h[0] == 0x01 +}