# scure-bip39

Secure, [audited](#security) & minimal implementation of BIP39 mnemonic phrases.

Compared to popular `bip39` package, scure-bip39:

- Supports ESM and common.js
- Supports tree-shaking: only actually used wordlists are bundled
- Is 491KB all-bundled instead of 1.3MB
- Uses 2 dependencies instead of 15
- Wordlists are 157KB instead of 315KB
- Had an external security [audit](#security) by Cure53

Check out [scure-bip32](https://github.com/paulmillr/scure-bip32) if you need
hierarchical deterministic wallets ("HD Wallets").

### This library belongs to *scure*

> **scure** — secure, independently audited packages for every use case.

- All releases are signed with PGP keys
- As minimal as possible
- Check out all libraries:
  [base](https://github.com/paulmillr/scure-base),
  [bip32](https://github.com/paulmillr/scure-bip32),
  [bip39](https://github.com/paulmillr/scure-bip39),
  [btc-signer](https://github.com/paulmillr/scure-btc-signer)

## Usage

> npm install @scure/bip39

Or

> yarn add @scure/bip39

```js
import * as bip39 from '@scure/bip39';
import { wordlist } from '@scure/bip39/wordlists/english';

// Generate x random words. Uses Cryptographically-Secure Random Number Generator.
const mn = bip39.generateMnemonic(wordlist);
console.log(mn);

// Reversible: Converts mnemonic string to raw entropy in form of byte array.
const ent = bip39.mnemonicToEntropy(mn, wordlist)

// Reversible: Converts raw entropy in form of byte array to mnemonic string.
bip39.entropyToMnemonic(ent, wordlist);

// Validates mnemonic for being 12-24 words contained in `wordlist`.
bip39.validateMnemonic(mn, wordlist);

// Irreversible: Uses KDF to derive 64 bytes of key data from mnemonic + optional password.
await bip39.mnemonicToSeed(mn, 'password');
bip39.mnemonicToSeedSync(mn, 'password');
```

This submodule contains the word lists defined by BIP39 for Czech, English, French, Italian, Japanese, Korean, Simplified and Traditional Chinese, and Spanish. These are not imported by default, as that would increase bundle sizes too much. Instead, you should import and use them explicitly.

```typescript
function generateMnemonic(wordlist: string[], strength?: number): string;
function mnemonicToEntropy(mnemonic: string, wordlist: string[]): Uint8Array;
function entropyToMnemonic(entropy: Uint8Array, wordlist: string[]): string;
function validateMnemonic(mnemonic: string, wordlist: string[]): boolean;
function mnemonicToSeed(mnemonic: string, passphrase?: string): Promise<Uint8Array>;
function mnemonicToSeedSync(mnemonic: string, passphrase?: string): Uint8Array;
```

All wordlists:

```typescript
import { wordlist as czech } from '@scure/bip39/wordlists/czech';
import { wordlist as english } from '@scure/bip39/wordlists/english';
import { wordlist as french } from '@scure/bip39/wordlists/french';
import { wordlist as italian } from '@scure/bip39/wordlists/italian';
import { wordlist as japanese } from '@scure/bip39/wordlists/japanese';
import { wordlist as korean } from '@scure/bip39/wordlists/korean';
import { wordlist as simp } from '@scure/bip39/wordlists/simplified-chinese';
import { wordlist as spanish } from '@scure/bip39/wordlists/spanish';
import { wordlist as trad } from '@scure/bip39/wordlists/traditional-chinese';
```

## Security

The library has been audited by Cure53 on Jan 5, 2022. Check out the audit [PDF](./audit/2022-01-05-cure53-audit-nbl2.pdf) & [URL](https://cure53.de/pentest-report_hashing-libs.pdf). See [changes since audit](https://github.com/paulmillr/scure-bip39/compare/1.0.0..main).

1. The library was initially developed for [js-ethereum-cryptography](https://github.com/ethereum/js-ethereum-cryptography)
2. At commit [ae00e6d7](https://github.com/ethereum/js-ethereum-cryptography/commit/ae00e6d7d24fb3c76a1c7fe10039f6ecd120b77e), it
  was extracted to a separate package called `micro-bip39`
3. After the audit we've decided to use NPM namespace for security. Since `@micro` namespace was taken, we've renamed the package to `@scure/bip39`

## License

[MIT License](./LICENSE)

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