noble-secp256k1

secp256k1, an elliptic curve that could be used for assymetric encryption and ECDSA signature scheme.

This library belongs to noble crypto

noble-crypto — high-security, easily auditable set of contained cryptographic libraries and tools.

  • No dependencies, one small file
  • Easily auditable TypeScript/JS code
  • Uses es2019 bigint. Supported in Chrome, Firefox, node 10+
  • All releases are signed and trusted
  • Check out all libraries: secp256k1, ed25519, ripemd160

Usage

npm install noble-secp256k1

import * as secp256k1 from "noble-secp256k1";

// You can also pass BigInt:
// const PRIVATE_KEY = 0xa665a45920422f9d417e4867efn;
const PRIVATE_KEY = Uint8Array.from([
  0xa6, 0x65, 0xa4, 0x59, 0x20, 0x42, 0x2f,
  0x9d, 0x41, 0x7e, 0x48, 0x67, 0xef
]);
const MESSAGE_HASH = "9c1185a5c5e9fc54612808977ee8f548b2258d31";

const publicKey = secp256k1.getPublicKey(PRIVATE_KEY);
const signature = secp256k1.sign(MESSAGE_HASH, PRIVATE_KEY);
const isMessageSigned = secp256k1.verify(signature, MESSAGE_HASH, publicKey);

API

function getPublicKey(privateKey: Uint8Array, isCompressed?: false): Uint8Array;
function getPublicKey(privateKey: string, isCompressed?: false): string;
function getPublicKey(privateKey: bigint): Point;

privateKey will be used to generate public key. Public key is generated by doing scalar multiplication of a base Point(x, y) by a fixed integer. The result is another Point(x, y) which we will by default encode to hex Uint8Array. isCompressed (default is false) determines whether the output should contain y coordinate of the point.

function sign(hash: Uint8Array, privateKey: Uint8Array | bigint, k?: bigint): Uint8Array;
function sign(hash: string, privateKey: string | bigint, k?: bigint): string;
  • hash: Uint8Array | string - message hash which would be signed
  • privateKey: Uint8Array | string | bigint - private key which will sign the hash
  • k?: bigint - optional random seed. Default is one from crypto.getRandomValues(). Must be cryptographically secure, which means Math.random() won't work.
  • Returns DER encoded ECDSA signature, as hex uint8a / string.
function verify(signature: Uint8Array | string | SignResult, hash: Uint8Array | string): boolean
  • signature: Uint8Array - object returned by the sign function
  • hash: string | Uint8Array - message hash that needs to be verified
  • publicKey: string | Point - e.g. that was generated from privateKey by getPublicKey
  • Returns boolean: true if signature == hash; otherwise false

The library also exports helpers:

// Finite field over prime Fp
secp256k1.P // 2 ^ 256 - 2 ^ 32 - 977

// Prime order
secp256k1.PRIME_ORDER // 2 ^ 256 - 432420386565659656852420866394968145599

// Base point
secp256k1.BASE_POINT // new secp256k1.Point(x, y) where
// x = 55066263022277343669578718895168534326250603453777594175500187360389116729240n
// y = 32670510020758816978083085130507043184471273380659243275938904335757337482424n;

// Elliptic curve point
secp256k1.Point {
  constructor(x: bigint, y: bigint);
  // Compressed elliptic curve point representation
  static fromHex(hex: Uint8Array | string);
  static fromCompressedHex(hex: string);
  toHex(): string;
  toCompressedHex(): string;
}
secp256k1.SignResult {
  constructor(r: bigint, s: bigint);
  // DER encoded ECDSA signature
  static fromHex(hex: Uint8Array | string);
  toHex()
}

License

MIT (c) Paul Miller (https://paulmillr.com), see LICENSE file.