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Merge pull request #3 from dcousens/master

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BIP39 compliance clarifications
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Wei Lu 2014-06-24 08:45:22 +08:00
commit b6798c95f8
2 changed files with 66 additions and 53 deletions
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85
index.js
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@ -1,79 +1,91 @@
var CryptoJS = require('crypto-js') var CryptoJS = require('crypto-js')
var path = require('path')
var includeFolder = require('include-folder')
var Wordlists = includeFolder(path.join(__dirname, 'wordlists'))
var crypto = require('crypto') var crypto = require('crypto')
module.exports = BIP39 var includeFolder = require('include-folder')
var path = require('path')
var wordlists = includeFolder(path.join(__dirname, 'wordlists'))
function BIP39(language){ function BIP39(language) {
language = language || 'en' language = language || 'en'
this.wordlist = JSON.parse(Wordlists[language]) this.wordlist = JSON.parse(wordlists[language])
} }
BIP39.prototype.mnemonicToSeed = function(mnemonic, password){ BIP39.prototype.mnemonicToSeed = function(mnemonic, password) {
var options = {iterations: 2048, hasher: CryptoJS.algo.SHA512, keySize: 512/32} var options = {iterations: 2048, hasher: CryptoJS.algo.SHA512, keySize: 512/32}
return CryptoJS.PBKDF2(mnemonic, salt(password), options).toString(CryptoJS.enc.Hex) return CryptoJS.PBKDF2(mnemonic, salt(password), options).toString(CryptoJS.enc.Hex)
} }
BIP39.prototype.entropyToMnemonic = function(entropy){ BIP39.prototype.entropyToMnemonic = function(entropy) {
var entropyBuffer = new Buffer(entropy, 'hex') var entropyBuffer = new Buffer(entropy, 'hex')
var hash = crypto.createHash('sha256').update(entropyBuffer).digest() var entropyBits = bytesToBinary([].slice.call(entropyBuffer))
var checksum = checksumBits(entropyBuffer)
var combined = Buffer.concat([entropyBuffer, hash]) var bits = entropyBits + checksum
var bitLength = entropyBuffer.length * 8 + entropyBuffer.length / 4 var chunks = bits.match(/(.{1,11})/g)
var bits = bytesToBinary([].slice.call(combined)).substr(0, bitLength)
var chunks = (bits).match(/(.{1,11})/g) var words = chunks.map(function(binary) {
return chunks.map(function(binary){
var index = parseInt(binary, 2) var index = parseInt(binary, 2)
return this.wordlist[index] return this.wordlist[index]
}, this).join(' ') }, this)
return words.join(' ')
} }
BIP39.prototype.generateMnemonic = function(strength){ BIP39.prototype.generateMnemonic = function(strength) {
strength = strength || 128 strength = strength || 128
var entropy = crypto.randomBytes(strength/8).toString('hex') var entropy = crypto.randomBytes(strength/8).toString('hex')
return this.entropyToMnemonic(entropy) return this.entropyToMnemonic(entropy)
} }
BIP39.prototype.validate = function(mnemonic){ BIP39.prototype.validate = function(mnemonic) {
mnemonic = mnemonic.split(' ') var words = mnemonic.split(' ')
if(mnemonic.length % 3 !== 0) return false if (words.length % 3 !== 0) return false
var wordlist = this.wordlist var wordlist = this.wordlist
var belongToList = mnemonic.reduce(function(memo, m){ var belongToList = words.every(function(word) {
return memo && (wordlist.indexOf(m) > -1) return wordlist.indexOf(word) > -1
}, true) })
if(!belongToList) return false if (!belongToList) return false
var bits = mnemonic.map(function(m){ // convert word indices to 11 bit binary strings
var id = wordlist.indexOf(m) var bits = words.map(function(word) {
return lpad(id.toString(2), '0', 11) var index = wordlist.indexOf(word)
return lpad(index.toString(2), '0', 11)
}).join('') }).join('')
var length = bits.length // split the binary string into ENT/CS
var dividerIndex = Math.floor(length / 33) * 32 var dividerIndex = Math.floor(bits.length / 33) * 32
var checksum = bits.substring(dividerIndex) var entropy = bits.slice(0, dividerIndex)
var checksum = bits.slice(dividerIndex)
var data = bits.substring(0, dividerIndex) // calculate the checksum and compare
var bytes = data.match(/(.{1,8})/g).map(function(bin){ var entropyBytes = entropy.match(/(.{1,8})/g).map(function(bin) {
return parseInt(bin, 2) return parseInt(bin, 2)
}) })
var hash = crypto.createHash('sha256').update(new Buffer(bytes)).digest() var entropyBuffer = new Buffer(entropyBytes)
var checksumBits = bytesToBinary([].slice.call(hash)) var newChecksum = checksumBits(entropyBuffer)
var checksum2 = checksumBits.substr(0, length - dividerIndex)
return checksum === checksum2 return newChecksum === checksum
}
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) { function salt(password) {
return encode_utf8('mnemonic' + (password || '')) return encode_utf8('mnemonic' + (password || ''))
} }
function encode_utf8(s){ function encode_utf8(s) {
return unescape(encodeURIComponent(s)) return unescape(encodeURIComponent(s))
} }
@ -90,3 +102,4 @@ function lpad(str, padString, length) {
return str; return str;
} }
module.exports = BIP39

34
test/index.js
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@ -1,49 +1,49 @@
var vectors = require('./vectors.json').english
var BIP39 = require('../index.js')
var wordlist = require('../wordlists/en.json')
var assert = require('assert') var assert = require('assert')
var wordlist = require('../wordlists/en.json')
var vectors = require('./vectors.json').english
var BIP39 = require('../index.js')
var bip39 = new BIP39() var bip39 = new BIP39()
describe('constructor', function(){ describe('constructor', function() {
it('defaults language to english', function(){ it('defaults language to english', function() {
assert.deepEqual(bip39.wordlist, wordlist) assert.deepEqual(bip39.wordlist, wordlist)
}) })
}) })
describe('mnemonicToSeed', function(){ describe('mnemonicToSeed', function() {
vectors.forEach(function(v, i){ vectors.forEach(function(v, i) {
it('works for tests vector ' + i, function(){ it('works for tests vector ' + i, function() {
assert.equal(bip39.mnemonicToSeed(v[1], 'TREZOR'), v[2]) assert.equal(bip39.mnemonicToSeed(v[1], 'TREZOR'), v[2])
}) })
}) })
}) })
describe('entropyToMnemonic', function(){ describe('entropyToMnemonic', function() {
vectors.forEach(function(v, i){ vectors.forEach(function(v, i) {
it('works for tests vector ' + i, function(){ it('works for tests vector ' + i, function() {
assert.equal(bip39.entropyToMnemonic(v[0]), v[1]) assert.equal(bip39.entropyToMnemonic(v[0]), v[1])
}) })
}) })
}) })
describe('validate', function(){ describe('validate', function() {
vectors.forEach(function(v, i){ vectors.forEach(function(v, i) {
it('passes check ' + i, function(){ it('passes check ' + i, function() {
assert(bip39.validate(v[1])) assert(bip39.validate(v[1]))
}) })
}) })
it('fails for mnemonics of wrong length', function(){ it('fails for mnemonics of wrong length', function() {
assert(!bip39.validate('sleep kitten')) assert(!bip39.validate('sleep kitten'))
assert(!bip39.validate('sleep kitten sleep kitten sleep kitten')) assert(!bip39.validate('sleep kitten sleep kitten sleep kitten'))
}) })
it('fails for mnemonics that contains words not from the word list', function(){ it('fails for mnemonics that contains words not from the word list', function() {
assert(!bip39.validate("turtle front uncle idea crush write shrug there lottery flower risky shell")) assert(!bip39.validate("turtle front uncle idea crush write shrug there lottery flower risky shell"))
}) })
it('fails for mnemonics of invalid checksum', function(){ it('fails for mnemonics of invalid checksum', function() {
assert(!bip39.validate('sleep kitten sleep kitten sleep kitten sleep kitten sleep kitten sleep kitten')) assert(!bip39.validate('sleep kitten sleep kitten sleep kitten sleep kitten sleep kitten sleep kitten'))
}) })
}) })