/*
* Copyright (c) 2013 Pavol Rusnak
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
* of the Software, and to permit persons to whom the Software is furnished to do
* so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/*
* Javascript port from python by Ian Coleman
*
* Requires code from sjcl
* https://github.com/bitwiseshiftleft/sjcl
*/
var Mnemonic = function(language) {
var PBKDF2_ROUNDS = 2048;
var RADIX = 2048;
var self = this;
var wordlist = [];
var hmacSHA512 = function(key) {
var hasher = new sjcl.misc.hmac(key, sjcl.hash.sha512);
this.encrypt = function() {
return hasher.encrypt.apply(hasher, arguments);
};
};
function init() {
wordlist = WORDLISTS[language];
if (wordlist.length != RADIX) {
err = 'Wordlist should contain ' + RADIX + ' words, but it contains ' + wordlist.length + ' words.';
throw err;
}
}
self.generate = function(strength) {
strength = strength || 128;
var r = strength % 32;
if (r > 0) {
throw 'Strength should be divisible by 32, but it is not (' + r + ').';
}
var hasStrongCrypto = 'crypto' in window && window['crypto'] !== null;
if (!hasStrongCrypto) {
throw 'Mnemonic should be generated with strong randomness, but crypto.getRandomValues is unavailable';
}
var buffer = new Uint8Array(strength / 8);
var data = crypto.getRandomValues(buffer);
return self.toMnemonic(data);
}
self.toMnemonic = function(byteArray) {
if (byteArray.length % 4 > 0) {
throw 'Data length in bits should be divisible by 32, but it is not (' + byteArray.length + ' bytes = ' + byteArray.length*8 + ' bits).'
}
//h = hashlib.sha256(data).hexdigest()
var data = byteArrayToWordArray(byteArray);
var hash = sjcl.hash.sha256.hash(data);
var h = sjcl.codec.hex.fromBits(hash);
// b is a binary string, eg '00111010101100...'
//b = bin(int(binascii.hexlify(data), 16))[2:].zfill(len(data) * 8) + \
// bin(int(h, 16))[2:].zfill(256)[:len(data) * 8 / 32]
//
// a = bin(int(binascii.hexlify(data), 16))[2:].zfill(len(data) * 8)
// c = bin(int(h, 16))[2:].zfill(256)
// d = c[:len(data) * 8 / 32]
var a = byteArrayToBinaryString(byteArray);
var c = zfill(hexStringToBinaryString(h), 256);
var d = c.substring(0, byteArray.length * 8 / 32);
// b = line1 + line2
var b = a + d;
var result = [];
var blen = b.length / 11;
for (var i=0; i<blen; i++) {
var idx = parseInt(b.substring(i * 11, (i + 1) * 11), 2);
result.push(wordlist[idx]);
}
return result.join(' ');
}
self.check = function(mnemonic) {
var mnemonic = mnemonic.split(' ')
if (mnemonic.length % 3 > 0) {
return false
}
// idx = map(lambda x: bin(self.wordlist.index(x))[2:].zfill(11), mnemonic)
var idx = [];
for (var i=0; i<mnemonic.length; i++) {
var word = mnemonic[i];
var wordIndex = wordlist.indexOf(word);
if (wordIndex == -1) {
return false;
}
var binaryIndex = zfill(wordIndex.toString(2), 11);
idx.push(binaryIndex);
}
var b = idx.join('');
var l = b.length;
//d = b[:l / 33 * 32]
//h = b[-l / 33:]
var d = b.substring(0, l / 33 * 32);
var h = b.substring(l - l / 33, l);
//nd = binascii.unhexlify(hex(int(d, 2))[2:].rstrip('L').zfill(l / 33 * 8))
var nd = binaryStringToWordArray(d);
//nh = bin(int(hashlib.sha256(nd).hexdigest(), 16))[2:].zfill(256)[:l / 33]
var ndHash = sjcl.hash.sha256.hash(nd);
var ndHex = sjcl.codec.hex.fromBits(ndHash);
var ndBstr = zfill(hexStringToBinaryString(ndHex), 256);
var nh = ndBstr.substring(0,l/33);
return h == nh;
}
self.toSeed = function(mnemonic, passphrase) {
passphrase = passphrase || '';
mnemonic = self.normalizeString(mnemonic)
passphrase = self.normalizeString(passphrase)
passphrase = "mnemonic" + passphrase;
var mnemonicBits = sjcl.codec.utf8String.toBits(mnemonic);
var passphraseBits = sjcl.codec.utf8String.toBits(passphrase);
var result = sjcl.misc.pbkdf2(mnemonicBits, passphraseBits, PBKDF2_ROUNDS, 512, hmacSHA512);
var hashHex = sjcl.codec.hex.fromBits(result);
return hashHex;
}
self.normalizeString = function(str) {
if (typeof str.normalize == "function") {
return str.normalize("NFKD");
}
else {
// TODO decide how to handle this in the future.
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/normalize
return str;
}
}
function byteArrayToWordArray(data) {
var a = [];
for (var i=0; i<data.length/4; i++) {
v = 0;
v += data[i*4 + 0] << 8 * 3;
v += data[i*4 + 1] << 8 * 2;
v += data[i*4 + 2] << 8 * 1;
v += data[i*4 + 3] << 8 * 0;
a.push(v);
}
return a;
}
function byteArrayToBinaryString(data) {
var bin = "";
for (var i=0; i<data.length; i++) {
bin += zfill(data[i].toString(2), 8);
}
return bin;
}
function hexStringToBinaryString(hexString) {
binaryString = "";
for (var i=0; i<hexString.length; i++) {
binaryString += zfill(parseInt(hexString[i], 16).toString(2),4);
}
return binaryString;
}
function binaryStringToWordArray(binary) {
var aLen = binary.length / 32;
var a = [];
for (var i=0; i<aLen; i++) {
var valueStr = binary.substring(0,32);
var value = parseInt(valueStr, 2);
a.push(value);
binary = binary.slice(32);
}
return a;
}
// Pad a numeric string on the left with zero digits until the given width
// is reached.
// Note this differs to the python implementation because it does not
// handle numbers starting with a sign.
function zfill(source, length) {
source = source.toString();
while (source.length < length) {
source = '0' + source;
}
return source;
}
init();
}
