ndn-js/contrib/securityLib/sha256.js

A JavaScript client library for Named Data Networking

/*
CryptoJS v3.1.2
code.google.com/p/crypto-js
(c) 2009-2013 by Jeff Mott. All rights reserved.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and 
associated documentation files (the "Software"), to deal in the Software without restriction, including 
without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or 
sell copies of the Software, and to permit persons to whom the Software is furnished to do so, 
subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

code.google.com/p/crypto-js/wiki/License
*/

var C = require('./core.js').CryptoJS;
(function (Math) {
    // Shortcuts
    var C_lib = C.lib;
    var WordArray = C_lib.WordArray;
    var Hasher = C_lib.Hasher;
    var C_algo = C.algo;

    // Initialization and round constants tables
    var H = [];
    var K = [];

    // Compute constants
    (function () {
        function isPrime(n) {
            var sqrtN = Math.sqrt(n);
            for (var factor = 2; factor <= sqrtN; factor++) {
                if (!(n % factor)) {
                    return false;
                }
            }

            return true;
        }

        function getFractionalBits(n) {
            return ((n - (n | 0)) * 0x100000000) | 0;
        }

        var n = 2;
        var nPrime = 0;
        while (nPrime < 64) {
            if (isPrime(n)) {
                if (nPrime < 8) {
                    H[nPrime] = getFractionalBits(Math.pow(n, 1 / 2));
                }
                K[nPrime] = getFractionalBits(Math.pow(n, 1 / 3));

                nPrime++;
            }

            n++;
        }
    }());

    // Reusable object
    var W = [];

    /**
     * SHA-256 hash algorithm.
     */
    var SHA256 = C_algo.SHA256 = Hasher.extend({
        _doReset: function () {
            this._hash = new WordArray.init(H.slice(0));
        },

        _doProcessBlock: function (M, offset) {
            // Shortcut
            var H = this._hash.words;

            // Working variables
            var a = H[0];
            var b = H[1];
            var c = H[2];
            var d = H[3];
            var e = H[4];
            var f = H[5];
            var g = H[6];
            var h = H[7];

            // Computation
            for (var i = 0; i < 64; i++) {
                if (i < 16) {
                    W[i] = M[offset + i] | 0;
                } else {
                    var gamma0x = W[i - 15];
                    var gamma0  = ((gamma0x << 25) | (gamma0x >>> 7))  ^
                                  ((gamma0x << 14) | (gamma0x >>> 18)) ^
                                   (gamma0x >>> 3);

                    var gamma1x = W[i - 2];
                    var gamma1  = ((gamma1x << 15) | (gamma1x >>> 17)) ^
                                  ((gamma1x << 13) | (gamma1x >>> 19)) ^
                                   (gamma1x >>> 10);

                    W[i] = gamma0 + W[i - 7] + gamma1 + W[i - 16];
                }

                var ch  = (e & f) ^ (~e & g);
                var maj = (a & b) ^ (a & c) ^ (b & c);

                var sigma0 = ((a << 30) | (a >>> 2)) ^ ((a << 19) | (a >>> 13)) ^ ((a << 10) | (a >>> 22));
                var sigma1 = ((e << 26) | (e >>> 6)) ^ ((e << 21) | (e >>> 11)) ^ ((e << 7)  | (e >>> 25));

                var t1 = h + sigma1 + ch + K[i] + W[i];
                var t2 = sigma0 + maj;

                h = g;
                g = f;
                f = e;
                e = (d + t1) | 0;
                d = c;
                c = b;
                b = a;
                a = (t1 + t2) | 0;
            }

            // Intermediate hash value
            H[0] = (H[0] + a) | 0;
            H[1] = (H[1] + b) | 0;
            H[2] = (H[2] + c) | 0;
            H[3] = (H[3] + d) | 0;
            H[4] = (H[4] + e) | 0;
            H[5] = (H[5] + f) | 0;
            H[6] = (H[6] + g) | 0;
            H[7] = (H[7] + h) | 0;
        },

        _doFinalize: function () {
            // Shortcuts
            var data = this._data;
            var dataWords = data.words;

            var nBitsTotal = this._nDataBytes * 8;
            var nBitsLeft = data.sigBytes * 8;

            // Add padding
            dataWords[nBitsLeft >>> 5] |= 0x80 << (24 - nBitsLeft % 32);
            dataWords[(((nBitsLeft + 64) >>> 9) << 4) + 14] = Math.floor(nBitsTotal / 0x100000000);
            dataWords[(((nBitsLeft + 64) >>> 9) << 4) + 15] = nBitsTotal;
            data.sigBytes = dataWords.length * 4;

            // Hash final blocks
            this._process();

            // Return final computed hash
            return this._hash;
        },

        clone: function () {
            var clone = Hasher.clone.call(this);
            clone._hash = this._hash.clone();

            return clone;
        }
    });

    /**
     * Shortcut function to the hasher's object interface.
     *
     * @param {WordArray|string} message The message to hash.
     *
     * @return {WordArray} The hash.
     *
     * @static
     *
     * @example
     *
     *     var hash = CryptoJS.SHA256('message');
     *     var hash = CryptoJS.SHA256(wordArray);
     */
    C.SHA256 = Hasher._createHelper(SHA256);

    /**
     * Shortcut function to the HMAC's object interface.
     *
     * @param {WordArray|string} message The message to hash.
     * @param {WordArray|string} key The secret key.
     *
     * @return {WordArray} The HMAC.
     *
     * @static
     *
     * @example
     *
     *     var hmac = CryptoJS.HmacSHA256(message, key);
     */
    C.HmacSHA256 = Hasher._createHmacHelper(SHA256);
}(Math));

exports.CryptoJS = C;
module.exports = exports;