mirror of https://github.com/status-im/bip39.git
106 lines
2.8 KiB
JavaScript
106 lines
2.8 KiB
JavaScript
var CryptoJS = require('crypto-js')
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var crypto = require('crypto')
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var secureRandom = require('secure-random')
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var DEFAULT_WORDLIST = require('./wordlists/en.json')
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function BIP39(wordlist) {
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this.wordlist = wordlist || DEFAULT_WORDLIST
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}
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BIP39.prototype.mnemonicToSeed = function(mnemonic, password) {
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var options = {iterations: 2048, hasher: CryptoJS.algo.SHA512, keySize: 512/32}
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return CryptoJS.PBKDF2(mnemonic, salt(password), options).toString(CryptoJS.enc.Hex)
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}
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BIP39.prototype.entropyToMnemonic = function(entropy) {
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var entropyBuffer = new Buffer(entropy, 'hex')
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var entropyBits = bytesToBinary([].slice.call(entropyBuffer))
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var checksum = checksumBits(entropyBuffer)
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var bits = entropyBits + checksum
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var chunks = bits.match(/(.{1,11})/g)
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var words = chunks.map(function(binary) {
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var index = parseInt(binary, 2)
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return this.wordlist[index]
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}, this)
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return words.join(' ')
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}
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BIP39.prototype.generateMnemonic = function(strength, rng) {
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strength = strength || 128
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rng = rng || secureRandom.randomBuffer
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var hex = rng(strength / 8).toString('hex')
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return this.entropyToMnemonic(hex, this.wordlist)
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}
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BIP39.prototype.validate = function(mnemonic) {
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var words = mnemonic.split(' ')
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if (words.length % 3 !== 0) return false
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var wordlist = this.wordlist
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var belongToList = words.every(function(word) {
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return wordlist.indexOf(word) > -1
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})
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if (!belongToList) return false
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// convert word indices to 11 bit binary strings
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var bits = words.map(function(word) {
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var index = wordlist.indexOf(word)
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return lpad(index.toString(2), '0', 11)
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}).join('')
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// split the binary string into ENT/CS
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var dividerIndex = Math.floor(bits.length / 33) * 32
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var entropy = bits.slice(0, dividerIndex)
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var checksum = bits.slice(dividerIndex)
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// calculate the checksum and compare
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var entropyBytes = entropy.match(/(.{1,8})/g).map(function(bin) {
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return parseInt(bin, 2)
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})
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var entropyBuffer = new Buffer(entropyBytes)
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var newChecksum = checksumBits(entropyBuffer)
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return newChecksum === checksum
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}
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function checksumBits(entropyBuffer) {
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var hash = crypto.createHash('sha256').update(entropyBuffer).digest()
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// Calculated constants from BIP39
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var ENT = entropyBuffer.length * 8
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var CS = ENT / 32
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return bytesToBinary([].slice.call(hash)).slice(0, CS)
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}
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function salt(password) {
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return encode_utf8('mnemonic' + (password || ''))
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}
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function encode_utf8(s) {
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return unescape(encodeURIComponent(s))
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}
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//=========== helper methods from bitcoinjs-lib ========
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function bytesToBinary(bytes) {
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return bytes.map(function(x) {
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return lpad(x.toString(2), '0', 8)
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}).join('');
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}
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function lpad(str, padString, length) {
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while (str.length < length) str = padString + str;
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return str;
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}
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module.exports = BIP39
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