noble-bip32ed25519

Pure TypeScript BIP32-Ed25519 key derivation built on @noble/curves and @noble/hashes. Drop-in replacement for @stricahq/bip32ed25519 without the ~40MB libsodium-wrappers-sumo dependency.

4.5KB compressed. No WASM, no native bindings, no async init. Just math.

Install

npm install noble-bip32ed25519

Usage

import { Bip32PrivateKey } from 'noble-bip32ed25519';

// Entropy from BIP39 mnemonic (16-32 bytes)
const root = Bip32PrivateKey.fromEntropy(entropy);

// CIP-1852 derivation: m/1852'/1815'/0'/0/0
const paymentKey = root
  .derive(0x80000000 + 1852)
  .derive(0x80000000 + 1815)
  .derive(0x80000000)
  .derive(0)
  .derive(0);

// Sign
const privateKey = paymentKey.toPrivateKey();
const signature = privateKey.sign(message);

// Verify
const publicKey = privateKey.toPublicKey();
publicKey.verify(message, signature); // true

// Address construction
const keyHash = publicKey.hash(); // blake2b-224, 28 bytes

API

Bip32PrivateKey

| Method | Returns | Description | |---|---|---| | static fromEntropy(entropy: Uint8Array) | Bip32PrivateKey | Root key from BIP39 entropy (PBKDF2-HMAC-SHA512, Icarus scheme) | | derive(index: number) | Bip32PrivateKey | Hardened if index >= 0x80000000, soft otherwise | | toPrivateKey() | PrivateKey | Extract signing key | | toBip32PublicKey() | Bip32PublicKey | For public-only (watch-only) derivation |

Bip32PublicKey

| Method | Returns | Description | |---|---|---| | derive(index: number) | Bip32PublicKey | Soft derivation only (throws on hardened) | | toPublicKey() | PublicKey | Extract public key |

PrivateKey

| Method | Returns | Description | |---|---|---| | sign(message: Uint8Array) | Uint8Array | Ed25519 signature (64 bytes) | | toPublicKey() | PublicKey | Derive public key | | toBytes() | Uint8Array | Raw key bytes (64 bytes: kL || kR) |

PublicKey

| Method | Returns | Description | |---|---|---| | verify(message: Uint8Array, signature: Uint8Array) | boolean | Ed25519 verification | | toBytes() | Uint8Array | Raw public key (32 bytes) | | hash() | Uint8Array | blake2b-224 hash (28 bytes) |

All methods are synchronous. All byte values are Uint8Array.

Migrating from @stricahq/bip32ed25519

The API shape is nearly identical. The main differences: fromEntropy() is synchronous (no await), all byte types are Uint8Array instead of Buffer (use Uint8Array.from(buffer) / Buffer.from(uint8array) at boundaries if needed), and toPublicKey() on Bip32PrivateKey is replaced by toBip32PublicKey() which returns a Bip32PublicKey capable of soft derivation — call .toPublicKey() on that if you just need the raw public key. The derivation paths, key bytes, signatures, and hashes are byte-identical to the libsodium-based implementation.

libsodium shim

For projects that depend on libsodium-wrappers-sumo transitively (e.g., via @cardano-sdk/crypto), this package provides a drop-in shim that implements the 12 libsodium functions the Cardano JS ecosystem actually uses:

import sodium from 'noble-bip32ed25519/sodium';

await sodium.ready; // resolves immediately — no WASM to load
sodium.crypto_sign_detached(message, secretKey);

Use it via bundler aliases to eliminate libsodium from your build:

# esbuild
esbuild --alias:libsodium-wrappers-sumo=noble-bip32ed25519/sodium ...

# webpack (resolve.alias)
{ 'libsodium-wrappers-sumo': 'noble-bip32ed25519/sodium' }

Or via package.json imports map:

{
  "imports": {
    "libsodium-wrappers-sumo": "noble-bip32ed25519/sodium"
  }
}

Implemented functions: crypto_auth_hmacsha512, crypto_hash_sha512, crypto_generichash, crypto_scalarmult_ed25519_base_noclamp, crypto_core_ed25519_add, crypto_core_ed25519_scalar_add, crypto_core_ed25519_scalar_mul, crypto_core_ed25519_scalar_reduce, crypto_sign_detached, crypto_sign_seed_keypair, crypto_sign_verify_detached, ready.

All functions are tested against actual libsodium-wrappers-sumo for byte-identical output.

How it works

@stricahq/bip32ed25519 uses three libsodium functions. This library replaces them with @noble/curves equivalents:

| libsodium | noble | |---|---| | crypto_scalarmult_ed25519_base_noclamp | ed25519.Point.BASE.multiply(scalar) | | crypto_core_ed25519_scalar_add | 256-bit little-endian integer addition | | crypto_core_ed25519_add | point1.add(point2) |

The test suite includes cross-library verification against @stricahq/bip32ed25519 to ensure byte-identical output for root keys, derived payment/stake keys, public key hashes, and signatures.

Contributing

Contributions, forks, and issues are welcome. This is a small, focused library — the entire implementation is ~340 lines across two files (src/crypto.ts and src/index.ts).

License

MIT