c-kzg-4844/bindings/node.js/kzg.ts

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/**
* The public interface of this module exposes the functions as specified by
* https://github.com/ethereum/consensus-specs/blob/dev/specs/eip4844/polynomial-commitments.md#kzg
*/
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const kzg: KZG = require("./kzg.node");
const fs = require("fs");
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export type BLSFieldElement = Uint8Array; // 32 bytes
export type KZGProof = Uint8Array; // 48 bytes
export type KZGCommitment = Uint8Array; // 48 bytes
export type Blob = Uint8Array; // 4096 * 32 bytes
type SetupHandle = Object;
// The C++ native addon interface
type KZG = {
FIELD_ELEMENTS_PER_BLOB: number;
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BYTES_PER_FIELD_ELEMENT: number;
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loadTrustedSetup: (filePath: string) => SetupHandle;
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freeTrustedSetup: (setupHandle: SetupHandle) => void;
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blobToKzgCommitment: (blob: Blob, setupHandle: SetupHandle) => KZGCommitment;
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computeAggregateKzgProof: (
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blobs: Blob[],
setupHandle: SetupHandle,
) => KZGProof;
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verifyAggregateKzgProof: (
blobs: Blob[],
expectedKzgCommitments: KZGCommitment[],
kzgAggregatedProof: KZGProof,
setupHandle: SetupHandle,
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) => boolean;
verifyKzgProof: (
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polynomialKzg: KZGCommitment,
z: BLSFieldElement,
y: BLSFieldElement,
kzgProof: KZGProof,
setupHandle: SetupHandle,
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) => boolean;
};
type TrustedSetupJSON = {
setup_G1: string[];
setup_G2: string[];
setup_G1_lagrange: string[];
roots_of_unity: string[];
};
export const FIELD_ELEMENTS_PER_BLOB = kzg.FIELD_ELEMENTS_PER_BLOB;
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export const BYTES_PER_FIELD_ELEMENT = kzg.BYTES_PER_FIELD_ELEMENT;
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// Stored as internal state
let setupHandle: SetupHandle | undefined;
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function requireSetupHandle(): SetupHandle {
if (!setupHandle) {
throw new Error("You must call loadTrustedSetup to initialize KZG.");
}
return setupHandle;
}
export async function transformTrustedSetupJSON(
filePath: string,
): Promise<string> {
const data: TrustedSetupJSON = JSON.parse(fs.readFileSync(filePath));
const textFilePath = filePath.replace(".json", "") + ".txt";
try {
fs.unlinkSync(textFilePath);
} catch {}
const file = fs.createWriteStream(textFilePath);
file.write(`${FIELD_ELEMENTS_PER_BLOB}\n65\n`);
file.write(data.setup_G1.map((p) => p.replace("0x", "")).join("\n"));
file.write(data.setup_G2.map((p) => p.replace("0x", "")).join("\n"));
file.end();
const p = new Promise((resolve) => {
file.close(resolve);
});
await p;
return textFilePath;
}
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export function loadTrustedSetup(filePath: string): void {
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if (setupHandle) {
throw new Error(
"Call freeTrustedSetup before loading a new trusted setup.",
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);
}
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setupHandle = kzg.loadTrustedSetup(filePath);
}
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export function freeTrustedSetup(): void {
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kzg.freeTrustedSetup(requireSetupHandle());
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setupHandle = undefined;
}
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export function blobToKzgCommitment(blob: Blob): KZGCommitment {
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return kzg.blobToKzgCommitment(blob, requireSetupHandle());
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}
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export function computeAggregateKzgProof(blobs: Blob[]): KZGProof {
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return kzg.computeAggregateKzgProof(blobs, requireSetupHandle());
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}
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export function verifyKzgProof(
polynomialKzg: KZGCommitment,
z: BLSFieldElement,
y: BLSFieldElement,
kzgProof: KZGProof,
): boolean {
return kzg.verifyKzgProof(
polynomialKzg,
z,
y,
kzgProof,
requireSetupHandle(),
);
}
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export function verifyAggregateKzgProof(
blobs: Blob[],
expectedKzgCommitments: KZGCommitment[],
kzgAggregatedProof: KZGProof,
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): boolean {
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return kzg.verifyAggregateKzgProof(
blobs,
expectedKzgCommitments,
kzgAggregatedProof,
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requireSetupHandle(),
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);
}