;(function (root, factory, undef) {
    if (typeof exports === "object") {
        // CommonJS
        module.exports = exports = factory(require("./core"), require("./sha1"), require("./hmac"));
    } else if (typeof define === "function" && define.amd) {
        // AMD
        define(["./core", "./sha1", "./hmac"], factory);
    } else {
        // Global (browser)
        factory(root.CryptoJS);
    }
}(this, function (CryptoJS) {

    (function () {
        // Shortcuts
        var C = CryptoJS;
        var C_lib = C.lib;
        var Base = C_lib.Base;
        var WordArray = C_lib.WordArray;
        var C_algo = C.algo;
        var SHA1 = C_algo.SHA1;
        var HMAC = C_algo.HMAC;

        /**
         * Password-Based Key Derivation Function 2 algorithm.
         */
        var PBKDF2 = C_algo.PBKDF2 = Base.extend({
            /**
             * Configuration options.
             *
             * @property {number} keySize The key size in words to generate. Default: 4 (128 bits)
             * @property {Hasher} hasher The hasher to use. Default: SHA1
             * @property {number} iterations The number of iterations to perform. Default: 1
             */
            cfg: Base.extend({
                keySize: 128 / 32,
                hasher: SHA1,
                iterations: 1
            }),

            /**
             * Initializes a newly created key derivation function.
             *
             * @param {Object} cfg (Optional) The configuration options to use for the derivation.
             *
             * @example
             *
             *     var kdf = CryptoJS.algo.PBKDF2.create();
             *     var kdf = CryptoJS.algo.PBKDF2.create({ keySize: 8 });
             *     var kdf = CryptoJS.algo.PBKDF2.create({ keySize: 8, iterations: 1000 });
             */
            init: function (cfg) {
                this.cfg = this.cfg.extend(cfg);
            },

            /**
             * Computes the Password-Based Key Derivation Function 2.
             *
             * @param {WordArray|string} password The password.
             * @param {WordArray|string} salt A salt.
             *
             * @return {WordArray} The derived key.
             *
             * @example
             *
             *     var key = kdf.compute(password, salt);
             */
            compute: function (password, salt) {
                // Shortcut
                var cfg = this.cfg;

                // Init HMAC
                var hmac = HMAC.create(cfg.hasher, password);

                // Initial values
                var derivedKey = WordArray.create();
                var blockIndex = WordArray.create([0x00000001]);

                // Shortcuts
                var derivedKeyWords = derivedKey.words;
                var blockIndexWords = blockIndex.words;
                var keySize = cfg.keySize;
                var iterations = cfg.iterations;

                // Generate key
                while (derivedKeyWords.length < keySize) {
                    var block = hmac.update(salt).finalize(blockIndex);
                    hmac.reset();

                    // Shortcuts
                    var blockWords = block.words;
                    var blockWordsLength = blockWords.length;

                    // Iterations
                    var intermediate = block;
                    for (var i = 1; i < iterations; i++) {
                        intermediate = hmac.finalize(intermediate);
                        hmac.reset();

                        // Shortcut
                        var intermediateWords = intermediate.words;

                        // XOR intermediate with block
                        for (var j = 0; j < blockWordsLength; j++) {
                            blockWords[j] ^= intermediateWords[j];
                        }
                    }

                    derivedKey.concat(block);
                    blockIndexWords[0]++;
                }
                derivedKey.sigBytes = keySize * 4;

                return derivedKey;
            }
        });

        /**
         * Computes the Password-Based Key Derivation Function 2.
         *
         * @param {WordArray|string} password The password.
         * @param {WordArray|string} salt A salt.
         * @param {Object} cfg (Optional) The configuration options to use for this computation.
         *
         * @return {WordArray} The derived key.
         *
         * @static
         *
         * @example
         *
         *     var key = CryptoJS.PBKDF2(password, salt);
         *     var key = CryptoJS.PBKDF2(password, salt, { keySize: 8 });
         *     var key = CryptoJS.PBKDF2(password, salt, { keySize: 8, iterations: 1000 });
         */
        C.PBKDF2 = function (password, salt, cfg) {
            return PBKDF2.create(cfg).compute(password, salt);
        };
    }());


    return CryptoJS.PBKDF2;

}));