85 lines
2.7 KiB
JavaScript
85 lines
2.7 KiB
JavaScript
var coinUtil = require('../util');
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var sjcl = require('./sjcl');
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var SecureRandom = require('./SecureRandom');
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var hmacSHA512 = function(key) {
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var hasher = new sjcl.misc.hmac(key, sjcl.hash.sha512);
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this.encrypt = function() {
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return hasher.encrypt.apply(hasher, arguments);
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};
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};
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var pbkdf2Sync_sha512 = function(password, salt, iterations, keylen) {
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var derivedKey = sjcl.misc.pbkdf2(password, salt, iterations, 512, hmacSHA512);
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return sjcl.codec.hex.fromBits(derivedKey)
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};
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var BIP39 = function() {};
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BIP39.mnemonic = function(wordlist, bits) {
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if (!bits)
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bits = 128;
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if (bits % 32 != 0)
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throw new Error("bits must be multiple of 32");
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var buf = SecureRandom.getRandomBuffer(bits / 8);
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return BIP39.entropy2mnemonic(wordlist, buf);
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}
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BIP39.entropy2mnemonic = function(wordlist, buf) {
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var hash = coinUtil.sha256(buf);
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var bin = "";
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var bits = buf.length * 8;
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for (var i = 0; i < buf.length; i++) {
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bin = bin + ("00000000" + buf[i].toString(2)).slice(-8);
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}
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var hashbits = hash[0].toString(2);
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hashbits = ("00000000" + hashbits).slice(-8).slice(0, bits / 32);
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bin = bin + hashbits;
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if (bin.length % 11 != 0)
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throw new Error("internal error - entropy not an even multiple of 11 bits - " + bin.length);
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var mnemonic = "";
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for (var i = 0; i < bin.length / 11; i++) {
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if (mnemonic != "")
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mnemonic = mnemonic + " ";
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var wi = parseInt(bin.slice(i * 11, (i + 1) * 11), 2);
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mnemonic = mnemonic + wordlist[wi];
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}
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return mnemonic;
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}
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BIP39.check = function(wordlist, mnemonic) {
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var words = mnemonic.split(' ');
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var bin = "";
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for (var i = 0; i < words.length; i++) {
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var ind = wordlist.indexOf(words[i]);
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if (ind < 0)
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return false;
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bin = bin + ("00000000000" + ind.toString(2)).slice(-11);
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}
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if (bin.length % 11 != 0) {
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throw new Error("internal error - entropy not an even multiple of 11 bits - " + bin.length);
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}
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var cs = bin.length / 33;
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var hash_bits = bin.slice(-cs);
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var nonhash_bits = bin.slice(0, bin.length - cs);
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var buf = new Buffer(nonhash_bits.length / 8);
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for (var i = 0; i < nonhash_bits.length / 8; i++) {
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buf.writeUInt8(parseInt(bin.slice(i * 8, (i + 1) * 8), 2), i);
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}
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var hash = coinUtil.sha256(buf);
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var expected_hash_bits = hash[0].toString(2);
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expected_hash_bits = ("00000000" + expected_hash_bits).slice(-8).slice(0, cs);
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return expected_hash_bits == hash_bits;
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}
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BIP39.mnemonic2seed = function(mnemonic, passphrase) {
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if (!passphrase)
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passphrase = "";
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var hex = pbkdf2Sync_sha512(mnemonic, "mnemonic" + passphrase, 2048, 64);
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var buf = new Buffer(hex, 'hex');
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return buf;
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}
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module.exports = BIP39;
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