You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 

123 lines
3.2 KiB

var assert = require('assert')
var crypto = require('crypto')
var pbkdf2 = require('pbkdf2-compat').pbkdf2Sync
var randomBytes = require('randombytes')
var unorm = require('unorm')
var DEFAULT_WORDLIST = require('./wordlists/en.json')
function mnemonicToSeed(mnemonic, password) {
return pbkdf2(mnemonic, salt(password), 2048, 64, 'sha512')
}
function mnemonicToSeedHex(mnemonic, password) {
return mnemonicToSeed(mnemonic, password).toString('hex')
}
function mnemonicToEntropy(mnemonic, wordlist) {
wordlist = wordlist || DEFAULT_WORDLIST
var words = mnemonic.split(' ')
assert(words.length % 3 === 0, 'Invalid mnemonic')
var belongToList = words.every(function(word) {
return wordlist.indexOf(word) > -1
})
assert(belongToList, 'Invalid mnemonic')
// convert word indices to 11 bit binary strings
var bits = words.map(function(word) {
var index = wordlist.indexOf(word)
return lpad(index.toString(2), '0', 11)
}).join('')
// split the binary string into ENT/CS
var dividerIndex = Math.floor(bits.length / 33) * 32
var entropy = bits.slice(0, dividerIndex)
var checksum = bits.slice(dividerIndex)
// calculate the checksum and compare
var entropyBytes = entropy.match(/(.{1,8})/g).map(function(bin) {
return parseInt(bin, 2)
})
var entropyBuffer = new Buffer(entropyBytes)
var newChecksum = checksumBits(entropyBuffer)
assert(newChecksum === checksum, 'Invalid mnemonic checksum')
return entropyBuffer.toString('hex')
}
function entropyToMnemonic(entropy, wordlist) {
wordlist = wordlist || DEFAULT_WORDLIST
var entropyBuffer = new Buffer(entropy, 'hex')
var entropyBits = bytesToBinary([].slice.call(entropyBuffer))
var checksum = checksumBits(entropyBuffer)
var bits = entropyBits + checksum
var chunks = bits.match(/(.{1,11})/g)
var words = chunks.map(function(binary) {
var index = parseInt(binary, 2)
return wordlist[index]
})
return words.join(' ')
}
function generateMnemonic(strength, rng, wordlist) {
strength = strength || 128
rng = rng || randomBytes
var hex = rng(strength / 8).toString('hex')
return entropyToMnemonic(hex, wordlist)
}
function validateMnemonic(mnemonic, wordlist) {
try {
mnemonicToEntropy(mnemonic, wordlist)
} catch (e) {
return false
}
return true
}
function checksumBits(entropyBuffer) {
var hash = crypto.createHash('sha256').update(entropyBuffer).digest()
// Calculated constants from BIP39
var ENT = entropyBuffer.length * 8
var CS = ENT / 32
return bytesToBinary([].slice.call(hash)).slice(0, CS)
}
function salt(password) {
return 'mnemonic' + (unorm.nfkd(password) || '') // Use unorm until String.prototype.normalize gets better browser support
}
//=========== helper methods from bitcoinjs-lib ========
function bytesToBinary(bytes) {
return bytes.map(function(x) {
return lpad(x.toString(2), '0', 8)
}).join('');
}
function lpad(str, padString, length) {
while (str.length < length) str = padString + str;
return str;
}
module.exports = {
mnemonicToSeed: mnemonicToSeed,
mnemonicToSeedHex: mnemonicToSeedHex,
mnemonicToEntropy: mnemonicToEntropy,
entropyToMnemonic: entropyToMnemonic,
generateMnemonic: generateMnemonic,
validateMnemonic: validateMnemonic
}