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
• ➰ 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. Notice Warnings about BIP32.

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/bip32

deno add jsr:@scure/bip32

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

import { HDKey } from '@scure/bip32';
import { sha256 } from '@noble/hashes/sha2.js';
import { randomBytes } from '@noble/hashes/utils.js';

const seed = randomBytes(32);
const root = HDKey.fromMasterSeed(seed);
const base58key = root.privateExtendedKey;
const restored = HDKey.fromExtendedKey(base58key);
const fromJson = HDKey.fromJSON({ xpriv: base58key });
const child = fromJson.derive("m/0/2147483647'/1");
const msgHash = sha256(new TextEncoder().encode('hello scure-bip32'));

// props
[root.depth, root.index, root.chainCode];
[restored.privateKey, restored.publicKey];
const sig = child.sign(msgHash);
child.verify(msgHash, sig);

Note: chainCode property is essentially a private part of a secret "master" key, it should be guarded from unauthorized access. Byte-array getters return copies so callers cannot mutate an HDKey's internal state. These snapshots remain caller-owned and are not zeroed by wipePrivateData().

For backwards compatibility, JSON.stringify() currently serializes both the private and public extended keys of an HDKey. Treat the result as secret key material. A future v3 release will make automatic JSON serialization public-only.

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 } | { xpub: string }): HDKey;

  readonly versions: Versions;
  readonly depth: number = 0;
  readonly index: number = 0;
  readonly parentFingerprint: number = 0;

  get fingerprint(): number;
  get identifier(): Uint8Array | undefined;
  get pubKeyHash(): Uint8Array | undefined;
  get privateKey(): Uint8Array | null;
  get publicKey(): Uint8Array | null;
  get chainCode(): 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;
  // TODO(v3): Make automatic JSON serialization public-only.
  toJSON(): { xpriv: string; xpub: string };
  // Explicitly exports private key material. Treat the result as a secret.
  toPrivateJSON(): { xpriv: string; xpub: string };
}

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.

Warnings about BIP32

BIP32 is a bad standard. It would be great if we've had something better.

• Network IDs (different currencies) are taken from a single GitHub document called SLIP-0044
• There were new projects, which did not yet have SLIP. Exchanges added support of those projects to their cold wallets. Then after the projects were added to SLIP, the exchanges were required to re-generate their cold wallets - a complicated task
• BIP32 is unusable for many different elliptic curves. For example, ETH2 uses bls12-381 curve, and with bip32 54% of generated keys would be invalid. So, they’re using much better BLS-only EIP-2333 as a replacement.
• It’s easy to shoot yourself in foot with non-hardened keys, which could allow simple de-anonimization of all addresses

Security

The library has been audited:

• at version 2.2.0, in Apr 2026, by ourselves (self-audited)
  • Scope: everything
  • Changes since audit
• at version 1.0.1, in Jan 2022, independently, 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. Be sure to verify the commit signatures
• Releases are made transparently through token-less GitHub CI and Trusted Publishing. Be sure to verify the provenance logs for authenticity.
• Rare releasing is practiced to minimize the need for re-audits by end-users.
• Dependencies are minimized and strictly pinned to reduce supply-chain risk.
  • We use as few dependencies as possible.
  • Version ranges are locked, and changes are checked with npm-diff.
• Dev dependencies are excluded from end-user installs; they’re only used for development and build steps.

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
• jsbt is 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

License

MIT License

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