isso/isso/js/app/lib/pbkdf2.js

define(["q", "app/lib/sha1"], function(Q, sha1) {
    /*
     * JavaScript implementation of Password-Based Key Derivation Function 2
     * (PBKDF2) as defined in RFC 2898.
     * Version 1.5
     * Copyright (c) 2007, 2008, 2009, 2010, 2011, 2012, 2013 Parvez Anandam
     * parvez@anandam.com
     * http://anandam.com/pbkdf2
     *
     * Distributed under the BSD license
     *
     * Uses Paul Johnston's excellent SHA-1 JavaScript library sha1.js:
     * http://pajhome.org.uk/crypt/md5/sha1.html
     * (uses the binb_sha1(), rstr2binb(), binb2str(), rstr2hex() functions from that libary)
     *
     * Thanks to Felix Gartsman for pointing out a bug in version 1.0
     * Thanks to Thijs Van der Schaeghe for pointing out a bug in version 1.1
     * Thanks to Richard Gautier for asking to clarify dependencies in version 1.2
     * Updated contact information from version 1.3
     * Thanks to Stuart Heinrich for pointing out updates to PAJ's SHA-1 library in version 1.4
     */


    /*
     * The four arguments to the constructor of the PBKDF2 object are
     * the password, salt, number of iterations and number of bytes in
     * generated key. This follows the RFC 2898 definition: PBKDF2 (P, S, c, dkLen)
     *
     * The method deriveKey takes two parameters, both callback functions:
     * the first is used to provide status on the computation, the second
     * is called with the result of the computation (the generated key in hex).
     *
     * Example of use:
     *
     *    <script src="sha1.js"></script>
     *    <script src="pbkdf2.js"></script>
     *    <script>
     *    var mypbkdf2 = new PBKDF2("mypassword", "saltines", 1000, 16);
     *    var status_callback = function(percent_done) {
     *        document.getElementById("status").innerHTML = "Computed " + percent_done + "%"};
     *    var result_callback = function(key) {
     *        document.getElementById("status").innerHTML = "The derived key is: " + key};
     *    mypbkdf2.deriveKey(status_callback, result_callback);
     *    </script>
     *    <div id="status"></div>
     *
     */

    var PBKDF2 = function(password, salt, num_iterations, num_bytes)
    {
        // Remember the password and salt
        var m_bpassword = sha1.rstr2binb(password);
        var m_salt = salt;

        // Total number of iterations
        var m_total_iterations = num_iterations;

        // Run iterations in chunks instead of all at once, so as to not block.
        // Define size of chunk here; adjust for slower or faster machines if necessary.
        var m_iterations_in_chunk = 10;

        // Iteration counter
        var m_iterations_done = 0;

        // Key length, as number of bytes
        var m_key_length = num_bytes;

        // The hash cache
        var m_hash = null;

        // The length (number of bytes) of the output of the pseudo-random function.
        // Since HMAC-SHA1 is the standard, and what is used here, it's 20 bytes.
        var m_hash_length = 20;

        // Number of hash-sized blocks in the derived key (called 'l' in RFC2898)
        var m_total_blocks = Math.ceil(m_key_length/m_hash_length);

        // Start computation with the first block
        var m_current_block = 1;

        // Used in the HMAC-SHA1 computations
        var m_ipad = new Array(16);
        var m_opad = new Array(16);

        // This is where the result of the iterations gets sotred
        var m_buffer = new Array(0x0,0x0,0x0,0x0,0x0);

        // The result
        var m_key = "";

        // This object
        var m_this_object = this;

        // The function to call with the result
        var m_result_func;

        // The function to call with status after computing every chunk
        var m_status_func;

        // Set up the HMAC-SHA1 computations
        if (m_bpassword.length > 16) m_bpassword = sha1.binb_sha1(m_bpassword, password.length * chrsz);
        for(var i = 0; i < 16; ++i)
        {
            m_ipad[i] = m_bpassword[i] ^ 0x36363636;
            m_opad[i] = m_bpassword[i] ^ 0x5C5C5C5C;
        }


        // Starts the computation
        this.deriveKey = function(status_callback, result_callback)
        {
            m_status_func = status_callback;
            m_result_func = result_callback;
            setTimeout(function() { m_this_object.do_PBKDF2_iterations() }, 0);
        }


        // The workhorse
        this.do_PBKDF2_iterations = function()
        {
            var iterations = m_iterations_in_chunk;
            if (m_total_iterations - m_iterations_done < m_iterations_in_chunk)
                iterations = m_total_iterations - m_iterations_done;

            for(var i=0; i<iterations; ++i)
            {
                // compute HMAC-SHA1
                if (m_iterations_done == 0)
                {
                    var salt_block = m_salt +
                        String.fromCharCode(m_current_block >> 24 & 0xF) +
                        String.fromCharCode(m_current_block >> 16 & 0xF) +
                        String.fromCharCode(m_current_block >>  8 & 0xF) +
                        String.fromCharCode(m_current_block       & 0xF);

                    m_hash = sha1.binb_sha1(m_ipad.concat(sha1.rstr2binb(salt_block)),
                        512 + salt_block.length * 8);
                    m_hash = sha1.binb_sha1(m_opad.concat(m_hash), 512 + 160);
                }
                else
                {
                    m_hash = sha1.binb_sha1(m_ipad.concat(m_hash),
                        512 + m_hash.length * 32);
                    m_hash = sha1.binb_sha1(m_opad.concat(m_hash), 512 + 160);
                }

                for(var j=0; j<m_hash.length; ++j)
                    m_buffer[j] ^= m_hash[j];

                m_iterations_done++;
            }

            // Call the status callback function
            m_status_func( (m_current_block - 1 + m_iterations_done/m_total_iterations) / m_total_blocks * 100);

            if (m_iterations_done < m_total_iterations)
            {
                setTimeout(function() { m_this_object.do_PBKDF2_iterations() }, 0);
            }
            else
            {
                if (m_current_block < m_total_blocks)
                {
                    // Compute the next block (T_i in RFC 2898)

                    m_key += sha1.rstr2hex(sha1.binb2rstr(m_buffer));

                    m_current_block++;
                    m_buffer = new Array(0x0,0x0,0x0,0x0,0x0);
                    m_iterations_done = 0;

                    setTimeout(function() { m_this_object.do_PBKDF2_iterations() }, 0);
                }
                else
                {
                    // We've computed the final block T_l; we're done.

                    var tmp = sha1.rstr2hex(sha1.binb2rstr(m_buffer));
                    m_key += tmp.substr(0, (m_key_length - (m_total_blocks - 1) * m_hash_length) * 2 );

                    // Call the result callback function
                    m_result_func(m_key);
                }
            }
        }
    }

    return function(text, salt, iterations, size) {

        var deferred = Q.defer();

        Q.when(text, function(text) {
            var pbkdf2 = new PBKDF2(text, salt, iterations, size);
            pbkdf2.deriveKey(function(bla) {}, function(rv) {
                deferred.resolve(rv);
            });
        })

        return deferred.promise;
    }
})