scure-starknet

Audited & minimal JS implementation of Starknet cryptography.

• 🔒 Audited by an independent security firm
• 🧜‍♂️ Stark curve, pedersen and poseidon hashes
• ➰ Uses noble-curves for underlying arithmetics

This library belongs to scure

scure — audited micro-libraries.

• Zero or minimal dependencies
• Highly readable TypeScript / JS code
• PGP-signed releases and transparent NPM builds
• Check out homepage & all libraries: base, bip32, bip39, btc-signer, sr25519, starknet

Usage

npm install @scure/starknet

jsr add jsr:@scure/starknet

import * as starknet from '@scure/starknet';

We support all major platforms and runtimes.

Note: the examples use the 'deepStrictEqual' function from the 'assert' built-in NodeJS module to compare values.

In Typescript, you must first install the '@types/node' npm package and then import like this: import { deepStrictEqual } from 'assert';.

In vanilla Javascript, just do this: const { deepStrictEqual } = require("assert");

Curve

import { deepStrictEqual } from 'node:assert';
import * as starknet from '@scure/starknet';

// Signing and verification
const privateKey = '2dccce1da22003777062ee0870e9881b460a8b7eca276870f57c601f182136c';
const publicKey = starknet.getPublicKey(privateKey);
const messageHash = 'c465dd6b1bbffdb05442eb17f5ca38ad1aa78a6f56bf4415bdee219114a47';
const sig = starknet.sign(messageHash, privateKey);
const { r, s } = sig;
deepStrictEqual(r.toString(16), '5f496f6f210b5810b2711c74c15c05244dad43d18ecbbdbe6ed55584bc3b0a2');
deepStrictEqual(s.toString(16), '4e8657b153787f741a67c0666bad6426c3741b478c8eaa3155196fc571416f3');
deepStrictEqual(starknet.verify(sig, messageHash, publicKey), true);

// Private key to StarkKey
deepStrictEqual(
  starknet.getStarkKey('0x178047D3869489C055D7EA54C014FFB834A069C9595186ABE04EA4D1223A03F'),
  '0x1895a6a77ae14e7987b9cb51329a5adfb17bd8e7c638f92d6892d76e51cebcf'
);

// Pedersen hash
deepStrictEqual(
  starknet.pedersen(
    '0x3d937c035c878245caf64531a5756109c53068da139362728feb561405371cb',
    '0x208a0a10250e382e1e4bbe2880906c2791bf6275695e02fbbc6aeff9cd8b31a'
  ),
  '0x30e480bed5fe53fa909cc0f8c4d99b8f9f2c016be4c41e13a4848797979c662'
);

// Create private key from ethereum signature
const ethSignature =
  '0x21fbf0696d5e0aa2ef41a2b4ffb623bcaf070461d61cf7251c74161f82fec3a43' +
  '70854bc0a34b3ab487c1bc021cd318c734c51ae29374f2beb0e6f2dd49b4bf41c';
deepStrictEqual(
  starknet.ethSigToPrivate(ethSignature),
  '766f11e90cd7c7b43085b56da35c781f8c067ac0d578eabdceebc4886435bda'
);

Private key from mnemonic

npm install @scure/bip32 @scure/bip39

import { deepStrictEqual } from 'node:assert';
import * as bip32 from '@scure/bip32';
import * as bip39 from '@scure/bip39';
import * as starknet from '@scure/starknet';

const layer = 'starkex';
const application = 'starkdeployement';
const mnemonic =
  'range mountain blast problem vibrant void vivid doctor cluster enough melody ' +
  'salt layer language laptop boat major space monkey unit glimpse pause change vibrant';
const ethAddress = '0xa4864d977b944315389d1765ffa7e66F74ee8cd7';
const hdKey = bip32.HDKey.fromMasterSeed(bip39.mnemonicToSeedSync(mnemonic)).derive(
  starknet.getAccountPath(layer, application, ethAddress, 0)
);
if (!hdKey.privateKey) throw new Error('expected hdKey.privateKey');
deepStrictEqual(
  starknet.grindKey(hdKey.privateKey),
  '6cf0a8bf113352eb863157a45c5e5567abb34f8d32cddafd2c22aa803f4892c'
);

Poseidon

Poseidon hash can be used in the following way:

type PoseidonFn = ReturnType<typeof poseidon> & {
  m: number;
  rate: number;
  capacity: number;
};
function poseidonHash(x: bigint, y: bigint, fn?: PoseidonFn): bigint;
function poseidonHashFunc(x: Uint8Array, y: Uint8Array, fn?: PoseidonFn): Uint8Array;
function poseidonHashSingle(x: bigint, fn?: PoseidonFn): bigint;
function poseidonHashMany(values: bigint[], fn?: PoseidonFn): bigint;

Utils

import { deepStrictEqual } from 'node:assert';
import * as starknet from '@scure/starknet';

// Hash list of elements (same as hashChain, but includes single values and preserves order)
deepStrictEqual(
  starknet.computeHashOnElements([1, 2, 3]),
  '0xf9d95fbf356fbeda26538c92f7040abe51bf142350f73c9ee5ba7c660bae71'
);

// Key grinding
deepStrictEqual(
  starknet.grindKey('86F3E7293141F20A8BAFF320E8EE4ACCB9D4A4BF2B4D295E8CEE784DB46E0519'),
  '5c8c8683596c732541a59e03007b2d30dbbbb873556fe65b5fb63c16688f941'
);

// Starknet keccak
deepStrictEqual(
  starknet.keccak(new TextEncoder().encode('hello')),
  0x8aff950685c2ed4bc3174f3472287b56d9517b9c948127319a09a7a36deac8n
);

Security

The library has been independently audited:

• at version 0.3.0, in Sep 2023, by Kudelski Security
  • PDFs: offline
  • Changes since audit
  • Scope: scure-starknet and its related abstract modules of noble-curves: curve, modular, poseidon, weierstrass
  • The audit has been funded by Starkware

Speed

npm run bench

Benchmark results on Apple M4:

pedersen x 1,131 ops/sec @ 883μs/op
poseidon x 10,916 ops/sec @ 91μs/op
verify x 820 ops/sec @ 1ms/op

Contributing & testing

1. Clone the repository
2. npm install to install build dependencies like TypeScript
3. npm run build to compile TypeScript code
4. npm run test will execute all main tests

Resources

• Starknet docs
• SNARK Security and Performance calculating security level of snarks.

License

The MIT License (MIT)

Copyright (c) 2022 Paul Miller (https://paulmillr.com)

See LICENSE file.