The bip39 npm package is a JavaScript implementation of the BIP39 standard for generating mnemonic codes for generating deterministic keys. It is commonly used in cryptocurrency applications for creating and managing mnemonic phrases, which can be used to derive cryptographic keys.

What are bip39's main functionalities?

Generate Mnemonic

This feature allows you to generate a random mnemonic phrase. The mnemonic phrase is a set of words that can be used to generate a deterministic wallet.

const bip39 = require('bip39');
const mnemonic = bip39.generateMnemonic();
console.log(mnemonic);

Validate Mnemonic

This feature allows you to validate a given mnemonic phrase. It checks if the mnemonic is valid according to the BIP39 standard.

const bip39 = require('bip39');
const mnemonic = 'praise you muffin lion enable neck grocery crumble super myself license ghost';
const isValid = bip39.validateMnemonic(mnemonic);
console.log(isValid);

Mnemonic to Seed

This feature converts a mnemonic phrase to a seed. The seed can be used to derive cryptographic keys.

const bip39 = require('bip39');
const mnemonic = 'praise you muffin lion enable neck grocery crumble super myself license ghost';
const seed = bip39.mnemonicToSeedSync(mnemonic).toString('hex');
console.log(seed);

Mnemonic to Seed with Password

This feature converts a mnemonic phrase to a seed using an optional password. The password adds an extra layer of security.

const bip39 = require('bip39');
const mnemonic = 'praise you muffin lion enable neck grocery crumble super myself license ghost';
const seed = bip39.mnemonicToSeedSync(mnemonic, 'password').toString('hex');
console.log(seed);

Other packages similar to bip39

BIP39

JavaScript implementation of Bitcoin BIP39: Mnemonic code for generating deterministic keys

Reminder for developers

Please remember to allow recovery from mnemonic phrases that have invalid checksums (or that you don't have the wordlist)

When a checksum is invalid, warn the user that the phrase is not something generated by your app, and ask if they would like to use it anyway. This way, your app only needs to hold the wordlists for your supported languages, but you can recover phrases made by other apps in other languages.

However, there should be other checks in place, such as checking to make sure the user is inputting 12 words or more separated by a space. ie. phrase.trim().split(/\s+/g).length >= 12

Examples

// Generate a random mnemonic (uses crypto.randomBytes under the hood), defaults to 128-bits of entropy
var mnemonic = bip39.generateMnemonic()
// => 'seed sock milk update focus rotate barely fade car face mechanic mercy'

bip39.mnemonicToSeedHex('basket actual')
// => '5cf2d4a8b0355e90295bdfc565a022a409af063d5365bb57bf74d9528f494bfa4400f53d8349b80fdae44082d7f9541e1dba2b003bcfec9d0d53781ca676651f'

bip39.mnemonicToSeed('basket actual')
// => <Buffer 5c f2 d4 a8 b0 35 5e 90 29 5b df c5 65 a0 22 a4 09 af 06 3d 53 65 bb 57 bf 74 d9 52 8f 49 4b fa 44 00 f5 3d 83 49 b8 0f da e4 40 82 d7 f9 54 1e 1d ba 2b ...>

bip39.validateMnemonic(mnemonic)
// => true

bip39.validateMnemonic('basket actual')
// => false

var bip39 = require('bip39')

// defaults to BIP39 English word list
// uses HEX strings for entropy
var mnemonic = bip39.entropyToMnemonic('00000000000000000000000000000000')
// => zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo wrong

// reversible
bip39.mnemonicToEntropy(mnemonic)
// => '133755ff'

FAQs

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Package last updated on 17 Aug 2017

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