src/js/jsbip39.js

   1 /*
   2  * Copyright (c) 2013 Pavol Rusnak
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a copy of
   5  * this software and associated documentation files (the "Software"), to deal in
   6  * the Software without restriction, including without limitation the rights to
   7  * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
   8  * of the Software, and to permit persons to whom the Software is furnished to do
   9  * so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice shall be included in all
  12  * copies or substantial portions of the Software.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  17  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  18  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  19  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  20  */
  21
  22 /*
  23  * Javascript port from python by Ian Coleman
  24  *
  25  * Requires code from sjcl
  26  * https://github.com/bitwiseshiftleft/sjcl
  27  */
  28
  29 var Mnemonic = function(language) {
  30
  31     var PBKDF2_ROUNDS = 2048;
  32     var RADIX = 2048;
  33
  34     var self = this;
  35     var wordlist = [];
  36
  37     var hmacSHA512 = function(key) {
  38         var hasher = new sjcl.misc.hmac(key, sjcl.hash.sha512);
  39         this.encrypt = function() {
  40             return hasher.encrypt.apply(hasher, arguments);
  41         };
  42     };
  43
  44     function init() {
  45         wordlist = WORDLISTS[language];
  46         if (wordlist.length != RADIX) {
  47             err = 'Wordlist should contain ' + RADIX + ' words, but it contains ' + wordlist.length + ' words.';
  48             throw err;
  49         }
  50     }
  51
  52     self.generate = function(strength) {
  53         strength = strength || 128;
  54         var r = strength % 32;
  55         if (r > 0) {
  56             throw 'Strength should be divisible by 32, but it is not (' + r + ').';
  57         }
  58         var hasStrongCrypto = 'crypto' in window && window['crypto'] !== null;
  59         if (!hasStrongCrypto) {
  60             throw 'Mnemonic should be generated with strong randomness, but crypto.getRandomValues is unavailable';
  61         }
  62         var buffer = new Uint8Array(strength / 8);
  63         var data = crypto.getRandomValues(buffer);
  64         return self.toMnemonic(data);
  65     }
  66
  67     self.toMnemonic = function(byteArray) {
  68         if (byteArray.length % 4 > 0) {
  69             throw 'Data length in bits should be divisible by 32, but it is not (' + byteArray.length + ' bytes = ' + byteArray.length*8 + ' bits).'
  70         }
  71
  72         //h = hashlib.sha256(data).hexdigest()
  73         var data = byteArrayToWordArray(byteArray);
  74         var hash = sjcl.hash.sha256.hash(data);
  75         var h = sjcl.codec.hex.fromBits(hash);
  76
  77         // b is a binary string, eg '00111010101100...'
  78         //b = bin(int(binascii.hexlify(data), 16))[2:].zfill(len(data) * 8) + \
  79         //    bin(int(h, 16))[2:].zfill(256)[:len(data) * 8 / 32]
  80         //
  81         // a = bin(int(binascii.hexlify(data), 16))[2:].zfill(len(data) * 8)
  82         // c = bin(int(h, 16))[2:].zfill(256)
  83         // d = c[:len(data) * 8 / 32]
  84         var a = byteArrayToBinaryString(byteArray);
  85         var c = zfill(hexStringToBinaryString(h), 256);
  86         var d = c.substring(0, byteArray.length * 8 / 32);
  87         // b = line1 + line2
  88         var b = a + d;
  89
  90         var result = [];
  91         var blen = b.length / 11;
  92         for (var i=0; i<blen; i++) {
  93             var idx = parseInt(b.substring(i * 11, (i + 1) * 11), 2);
  94             result.push(wordlist[idx]);
  95         }
  96         return self.joinWords(result);
  97     }
  98
  99     self.check = function(mnemonic) {
 100         var mnemonic = self.splitWords(mnemonic);
 101         if (mnemonic.length == 0 || mnemonic.length % 3 > 0) {
 102             return false
 103         }
 104         // idx = map(lambda x: bin(self.wordlist.index(x))[2:].zfill(11), mnemonic)
 105         var idx = [];
 106         for (var i=0; i<mnemonic.length; i++) {
 107             var word = mnemonic[i];
 108             var wordIndex = wordlist.indexOf(word);
 109             if (wordIndex == -1) {
 110                 return false;
 111             }
 112             var binaryIndex = zfill(wordIndex.toString(2), 11);
 113             idx.push(binaryIndex);
 114         }
 115         var b = idx.join('');
 116         var l = b.length;
 117         //d = b[:l / 33 * 32]
 118         //h = b[-l / 33:]
 119         var d = b.substring(0, l / 33 * 32);
 120         var h = b.substring(l - l / 33, l);
 121         //nd = binascii.unhexlify(hex(int(d, 2))[2:].rstrip('L').zfill(l / 33 * 8))
 122         var nd = binaryStringToWordArray(d);
 123         //nh = bin(int(hashlib.sha256(nd).hexdigest(), 16))[2:].zfill(256)[:l / 33]
 124         var ndHash = sjcl.hash.sha256.hash(nd);
 125         var ndHex = sjcl.codec.hex.fromBits(ndHash);
 126         var ndBstr = zfill(hexStringToBinaryString(ndHex), 256);
 127         var nh = ndBstr.substring(0,l/33);
 128         return h == nh;
 129     }
 130
 131     self.toSeed = function(mnemonic, passphrase) {
 132         passphrase = passphrase || '';
 133         mnemonic = self.joinWords(self.splitWords(mnemonic)); // removes duplicate blanks
 134         var mnemonicNormalized = self.normalizeString(mnemonic);
 135         passphrase = self.normalizeString(passphrase)
 136         passphrase = "mnemonic" + passphrase;
 137         var mnemonicBits = sjcl.codec.utf8String.toBits(mnemonicNormalized);
 138         var passphraseBits = sjcl.codec.utf8String.toBits(passphrase);
 139         var result = sjcl.misc.pbkdf2(mnemonicBits, passphraseBits, PBKDF2_ROUNDS, 512, hmacSHA512);
 140         var hashHex = sjcl.codec.hex.fromBits(result);
 141         return hashHex;
 142     }
 143
 144     self.splitWords = function(mnemonic) {
 145         return mnemonic.split(/\s/g).filter(function(x) { return x.length; });
 146     }
 147
 148     self.joinWords = function(words) {
 149         // Set space correctly depending on the language
 150         // see https://github.com/bitcoin/bips/blob/master/bip-0039/bip-0039-wordlists.md#japanese
 151         var space = " ";
 152         if (language == "japanese") {
 153             space = "\u3000"; // ideographic space
 154         }
 155         return words.join(space);
 156     }
 157
 158     self.normalizeString = function(str) {
 159         if (typeof str.normalize == "function") {
 160             return str.normalize("NFKD");
 161         }
 162         else {
 163             // TODO decide how to handle this in the future.
 164             // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/normalize
 165             return str;
 166         }
 167     }
 168
 169     function byteArrayToWordArray(data) {
 170         var a = [];
 171         for (var i=0; i<data.length/4; i++) {
 172             v = 0;
 173             v += data[i*4 + 0] << 8 * 3;
 174             v += data[i*4 + 1] << 8 * 2;
 175             v += data[i*4 + 2] << 8 * 1;
 176             v += data[i*4 + 3] << 8 * 0;
 177             a.push(v);
 178         }
 179         return a;
 180     }
 181
 182     function byteArrayToBinaryString(data) {
 183         var bin = "";
 184         for (var i=0; i<data.length; i++) {
 185             bin += zfill(data[i].toString(2), 8);
 186         }
 187         return bin;
 188     }
 189
 190     function hexStringToBinaryString(hexString) {
 191         binaryString = "";
 192         for (var i=0; i<hexString.length; i++) {
 193             binaryString += zfill(parseInt(hexString[i], 16).toString(2),4);
 194         }
 195         return binaryString;
 196     }
 197
 198     function binaryStringToWordArray(binary) {
 199         var aLen = binary.length / 32;
 200         var a = [];
 201         for (var i=0; i<aLen; i++) {
 202             var valueStr = binary.substring(0,32);
 203             var value = parseInt(valueStr, 2);
 204             a.push(value);
 205             binary = binary.slice(32);
 206         }
 207         return a;
 208     }
 209
 210     // Pad a numeric string on the left with zero digits until the given width
 211     // is reached.
 212     // Note this differs to the python implementation because it does not
 213     // handle numbers starting with a sign.
 214     function zfill(source, length) {
 215         source = source.toString();
 216         while (source.length < length) {
 217             source = '0' + source;
 218         }
 219         return source;
 220     }
 221
 222     init();
 223
 224 }