scure-bip32

Audited & minimal implementation of BIP32 hierarchical deterministic (HD) wallets over secp256k1.

• 🔒 Audited by an independent security firm
• 🔻 Tree-shakeable: unused code is excluded from your builds
• 📦 ESM and common.js
• ➰ Only 3 audited dependencies by the same author: noble-curves, noble-hashes, and scure-base
• 🪶 18KB gzipped with all dependencies bundled

Check out scure-bip39 if you need mnemonic phrases. See key-producer if you need SLIP-0010/BIP32 ed25519 hdkey implementation.

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, starknet

Usage

npm install @scure/bip32

deno add jsr:@scure/bip32

deno doc jsr:@scure/bip32 # command-line documentation

This module exports a single class HDKey, which should be used like this:

import { HDKey } from '@scure/bip32';
const hdkey1 = HDKey.fromMasterSeed(seed);
const hdkey2 = HDKey.fromExtendedKey(base58key);
const hdkey3 = HDKey.fromJSON({ xpriv: string });

// props
[hdkey1.depth, hdkey1.index, hdkey1.chainCode];
console.log(hdkey2.privateKey, hdkey2.publicKey);
console.log(hdkey3.derive("m/0/2147483647'/1"));
const sig = hdkey3.sign(hash);
hdkey3.verify(hash, sig);

Note: chainCode property is essentially a private part of a secret "master" key, it should be guarded from unauthorized access.

The full API is:

class HDKey {
  public static HARDENED_OFFSET: number;
  public static fromMasterSeed(seed: Uint8Array, versions: Versions): HDKey;
  public static fromExtendedKey(base58key: string, versions: Versions): HDKey;
  public static fromJSON(json: { xpriv: string }): HDKey;

  readonly versions: Versions;
  readonly depth: number = 0;
  readonly index: number = 0;
  readonly chainCode: Uint8Array | null = null;
  readonly parentFingerprint: number = 0;

  get fingerprint(): number;
  get identifier(): Uint8Array | undefined;
  get pubKeyHash(): Uint8Array | undefined;
  get privateKey(): Uint8Array | null;
  get publicKey(): Uint8Array | null;
  get privateExtendedKey(): string;
  get publicExtendedKey(): string;

  derive(path: string): HDKey;
  deriveChild(index: number): HDKey;
  sign(hash: Uint8Array): Uint8Array;
  verify(hash: Uint8Array, signature: Uint8Array): boolean;
  wipePrivateData(): this;
}

interface Versions {
  private: number;
  public: number;
}

The module implements bip32 standard: check it out for additional documentation.

The implementation is loosely based on cryptocoinjs/hdkey, which has MIT License.

Security

The library has been independently audited:

• at version 1.0.1, in Jan 2022, by cure53
  • PDFs: online, offline
  • Changes since audit.
  • The audit has been funded by Ethereum Foundation with help of Nomic Labs

The library was initially developed for js-ethereum-cryptography. At commit ae00e6d7, it was extracted to a separate package called micro-bip32. After the audit we've decided to use @scure NPM namespace for security.

Supply chain security

• Commits are signed with PGP keys, to prevent forgery. Make sure to verify commit signatures
• Releases are transparent and built on GitHub CI. Make sure to verify provenance logs
• Rare releasing is followed to ensure less re-audit need for end-users
• Dependencies are minimized and locked-down: any dependency could get hacked and users will be downloading malware with every install.
  • We make sure to use as few dependencies as possible
  • Automatic dep updates are prevented by locking-down version ranges; diffs are checked with npm-diff
• Dev Dependencies are disabled for end-users; they are only used to develop / build the source code

For this package, there are 3 dependencies; and a few dev dependencies:

• noble-hashes provides cryptographic hashing functionality
• noble-curves provides ECDSA
• scure-base provides base58
• micro-bmark, micro-should and jsbt are used for benchmarking / testing / build tooling and developed by the same author
• prettier, fast-check and typescript are used for code quality / test generation / ts compilation. It's hard to audit their source code thoroughly and fully because of their size

Contributing & testing

• npm install && npm run build && npm test will build the code and run tests.
• npm run lint / npm run format will run linter / fix linter issues.
• npm run build:release will build single file

License

MIT License

Copyright (c) 2022 Patricio Palladino, Paul Miller (paulmillr.com)