84 lines
3.2 KiB
JavaScript
84 lines
3.2 KiB
JavaScript
import { sha256 } from 'ethereum-cryptography/sha256.js';
|
|
import { utf8ToBytes } from './bytes.js';
|
|
/**
|
|
* These utilities for constructing blobs are borrowed from https://github.com/Inphi/eip4844-interop.git
|
|
*/
|
|
const BYTES_PER_FIELD_ELEMENT = 32;
|
|
const FIELD_ELEMENTS_PER_BLOB = 4096;
|
|
const USEFUL_BYTES_PER_BLOB = 32 * FIELD_ELEMENTS_PER_BLOB;
|
|
const MAX_BLOBS_PER_TX = 2;
|
|
const MAX_USEFUL_BYTES_PER_TX = USEFUL_BYTES_PER_BLOB * MAX_BLOBS_PER_TX - 1;
|
|
const BLOB_SIZE = BYTES_PER_FIELD_ELEMENT * FIELD_ELEMENTS_PER_BLOB;
|
|
function get_padded(data, blobs_len) {
|
|
const pdata = new Uint8Array(blobs_len * USEFUL_BYTES_PER_BLOB).fill(0);
|
|
pdata.set(data);
|
|
pdata[data.byteLength] = 0x80;
|
|
return pdata;
|
|
}
|
|
function get_blob(data) {
|
|
const blob = new Uint8Array(BLOB_SIZE);
|
|
for (let i = 0; i < FIELD_ELEMENTS_PER_BLOB; i++) {
|
|
const chunk = new Uint8Array(32);
|
|
chunk.set(data.subarray(i * 31, (i + 1) * 31), 0);
|
|
blob.set(chunk, i * 32);
|
|
}
|
|
return blob;
|
|
}
|
|
export const getBlobs = (input) => {
|
|
const data = utf8ToBytes(input);
|
|
const len = data.byteLength;
|
|
if (len === 0) {
|
|
throw Error('invalid blob data');
|
|
}
|
|
if (len > MAX_USEFUL_BYTES_PER_TX) {
|
|
throw Error('blob data is too large');
|
|
}
|
|
const blobs_len = Math.ceil(len / USEFUL_BYTES_PER_BLOB);
|
|
const pdata = get_padded(data, blobs_len);
|
|
const blobs = [];
|
|
for (let i = 0; i < blobs_len; i++) {
|
|
const chunk = pdata.subarray(i * USEFUL_BYTES_PER_BLOB, (i + 1) * USEFUL_BYTES_PER_BLOB);
|
|
const blob = get_blob(chunk);
|
|
blobs.push(blob);
|
|
}
|
|
return blobs;
|
|
};
|
|
export const blobsToCommitments = (kzg, blobs) => {
|
|
const commitments = [];
|
|
for (const blob of blobs) {
|
|
commitments.push(kzg.blobToKzgCommitment(blob));
|
|
}
|
|
return commitments;
|
|
};
|
|
export const blobsToProofs = (kzg, blobs, commitments) => {
|
|
const proofs = blobs.map((blob, ctx) => kzg.computeBlobKzgProof(blob, commitments[ctx]));
|
|
return proofs;
|
|
};
|
|
/**
|
|
* Converts a vector commitment for a given data blob to its versioned hash. For 4844, this version
|
|
* number will be 0x01 for KZG vector commitments but could be different if future vector commitment
|
|
* types are introduced
|
|
* @param commitment a vector commitment to a blob
|
|
* @param blobCommitmentVersion the version number corresponding to the type of vector commitment
|
|
* @returns a versioned hash corresponding to a given blob vector commitment
|
|
*/
|
|
export const computeVersionedHash = (commitment, blobCommitmentVersion) => {
|
|
const computedVersionedHash = new Uint8Array(32);
|
|
computedVersionedHash.set([blobCommitmentVersion], 0);
|
|
computedVersionedHash.set(sha256(commitment).subarray(1), 1);
|
|
return computedVersionedHash;
|
|
};
|
|
/**
|
|
* Generate an array of versioned hashes from corresponding kzg commitments
|
|
* @param commitments array of kzg commitments
|
|
* @returns array of versioned hashes
|
|
* Note: assumes KZG commitments (version 1 version hashes)
|
|
*/
|
|
export const commitmentsToVersionedHashes = (commitments) => {
|
|
const hashes = [];
|
|
for (const commitment of commitments) {
|
|
hashes.push(computeVersionedHash(commitment, 0x01));
|
|
}
|
|
return hashes;
|
|
};
|
|
//# sourceMappingURL=blobs.js.map
|