corrade-nucleus-nucleons – Rev 20

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(function(){

var C = (typeof window === 'undefined') ? require('./Crypto').Crypto : window.Crypto;

// Shortcuts
var util = C.util,
    charenc = C.charenc,
    UTF8 = charenc.UTF8,
    Binary = charenc.Binary;

C.PBKDF2 = function (password, salt, keylen, options) {

        // Convert to byte arrays
        if (password.constructor == String) password = UTF8.stringToBytes(password);
        if (salt.constructor == String) salt = UTF8.stringToBytes(salt);
        /* else, assume byte arrays already */

        // Defaults
        var hasher = options && options.hasher || C.SHA1,
            iterations = options && options.iterations || 1;

        // Pseudo-random function
        function PRF(password, salt) {
                return C.HMAC(hasher, salt, password, { asBytes: true });
        }

        // Generate key
        var derivedKeyBytes = [],
            blockindex = 1;
        while (derivedKeyBytes.length < keylen) {
                var block = PRF(password, salt.concat(util.wordsToBytes([blockindex])));
                for (var u = block, i = 1; i < iterations; i++) {
                        u = PRF(password, u);
                        for (var j = 0; j < block.length; j++) block[j] ^= u[j];
                }
                derivedKeyBytes = derivedKeyBytes.concat(block);
                blockindex++;
        }

        // Truncate excess bytes
        derivedKeyBytes.length = keylen;

        return options && options.asBytes ? derivedKeyBytes :
               options && options.asString ? Binary.bytesToString(derivedKeyBytes) :
               util.bytesToHex(derivedKeyBytes);

};

})();