Example for crypto-js#259

core.js

/*globals window, global, require*/

/**
 * CryptoJS core components.
 */
var CryptoJS = CryptoJS || (function (Math, undefined) {

    var crypto;

    // Native crypto from window (Browser)
    if (typeof window !== 'undefined' && window.crypto) {
        crypto = window.crypto;
    }

    // Native (experimental IE 11) crypto from window (Browser)
    if (!crypto && typeof window !== 'undefined' && window.msCrypto) {
        crypto = window.msCrypto;
    }

    // Native crypto from global (NodeJS)
    if (!crypto && typeof global !== 'undefined' && global.crypto) {
        crypto = global.crypto;
    }

    /* delete all the `require()` for RN support as modern NodeJS will not reach the following line */
    // Native crypto import via require (NodeJS)
    /* deleted */
    

    /*
     * Cryptographically secure pseudorandom number generator
     *
     * As Math.random() is cryptographically not safe to use
     */
    var cryptoSecureRandomInt = function () {
        if (crypto) {
            // Use getRandomValues method (Browser)
            if (typeof crypto.getRandomValues === 'function') {
                try {
                    return crypto.getRandomValues(new Uint32Array(1))[0];
                } catch (err) {}
            }

            // Use randomBytes method (NodeJS)
            if (typeof crypto.randomBytes === 'function') {
                try {
                    return crypto.randomBytes(4).readInt32LE();
                } catch (err) {}
            }
        }

        throw new Error('Native crypto module could not be used to get secure random number.');
    };

    /*
     * Local polyfill of Object.create
     */
    var create = Object.create || (function () {
        function F() {}

        return function (obj) {
            var subtype;

            F.prototype = obj;

            subtype = new F();

            F.prototype = null;

            return subtype;
        };
    }())

    /**
     * CryptoJS namespace.
     */
    var C = {};

    /**
     * Library namespace.
     */
    var C_lib = C.lib = {};

    /**
     * Base object for prototypal inheritance.
     */
    var Base = C_lib.Base = (function () {


        return {
            /**
             * Creates a new object that inherits from this object.
             *
             * @param {Object} overrides Properties to copy into the new object.
             *
             * @return {Object} The new object.
             *
             * @static
             *
             * @example
             *
             *     var MyType = CryptoJS.lib.Base.extend({
             *         field: 'value',
             *
             *         method: function () {
             *         }
             *     });
             */
            extend: function (overrides) {
                // Spawn
                var subtype = create(this);

                // Augment
                if (overrides) {
                    subtype.mixIn(overrides);
                }

                // Create default initializer
                if (!subtype.hasOwnProperty('init') || this.init === subtype.init) {
                    subtype.init = function () {
                        subtype.$super.init.apply(this, arguments);
                    };
                }

                // Initializer's prototype is the subtype object
                subtype.init.prototype = subtype;

                // Reference supertype
                subtype.$super = this;

                return subtype;
            },

            /**
             * Extends this object and runs the init method.
             * Arguments to create() will be passed to init().
             *
             * @return {Object} The new object.
             *
             * @static
             *
             * @example
             *
             *     var instance = MyType.create();
             */
            create: function () {
                var instance = this.extend();
                instance.init.apply(instance, arguments);

                return instance;
            },

            /**
             * Initializes a newly created object.
             * Override this method to add some logic when your objects are created.
             *
             * @example
             *
             *     var MyType = CryptoJS.lib.Base.extend({
             *         init: function () {
             *             // ...
             *         }
             *     });
             */
            init: function () {
            },

            /**
             * Copies properties into this object.
             *
             * @param {Object} properties The properties to mix in.
             *
             * @example
             *
             *     MyType.mixIn({
             *         field: 'value'
             *     });
             */
            mixIn: function (properties) {
                for (var propertyName in properties) {
                    if (properties.hasOwnProperty(propertyName)) {
                        this[propertyName] = properties[propertyName];
                    }
                }

                // IE won't copy toString using the loop above
                if (properties.hasOwnProperty('toString')) {
                    this.toString = properties.toString;
                }
            },

            /**
             * Creates a copy of this object.
             *
             * @return {Object} The clone.
             *
             * @example
             *
             *     var clone = instance.clone();
             */
            clone: function () {
                return this.init.prototype.extend(this);
            }
        };
    }());

    /**
     * An array of 32-bit words.
     *
     * @property {Array} words The array of 32-bit words.
     * @property {number} sigBytes The number of significant bytes in this word array.
     */
    var WordArray = C_lib.WordArray = Base.extend({
        /**
         * Initializes a newly created word array.
         *
         * @param {Array} words (Optional) An array of 32-bit words.
         * @param {number} sigBytes (Optional) The number of significant bytes in the words.
         *
         * @example
         *
         *     var wordArray = CryptoJS.lib.WordArray.create();
         *     var wordArray = CryptoJS.lib.WordArray.create([0x00010203, 0x04050607]);
         *     var wordArray = CryptoJS.lib.WordArray.create([0x00010203, 0x04050607], 6);
         */
        init: function (words, sigBytes) {
            words = this.words = words || [];

            if (sigBytes != undefined) {
                this.sigBytes = sigBytes;
            } else {
                this.sigBytes = words.length * 4;
            }
        },

        /**
         * Converts this word array to a string.
         *
         * @param {Encoder} encoder (Optional) The encoding strategy to use. Default: CryptoJS.enc.Hex
         *
         * @return {string} The stringified word array.
         *
         * @example
         *
         *     var string = wordArray + '';
         *     var string = wordArray.toString();
         *     var string = wordArray.toString(CryptoJS.enc.Utf8);
         */
        toString: function (encoder) {
            return (encoder || Hex).stringify(this);
        },

        /**
         * Concatenates a word array to this word array.
         *
         * @param {WordArray} wordArray The word array to append.
         *
         * @return {WordArray} This word array.
         *
         * @example
         *
         *     wordArray1.concat(wordArray2);
         */
        concat: function (wordArray) {
            // Shortcuts
            var thisWords = this.words;
            var thatWords = wordArray.words;
            var thisSigBytes = this.sigBytes;
            var thatSigBytes = wordArray.sigBytes;

            // Clamp excess bits
            this.clamp();

            // Concat
            if (thisSigBytes % 4) {
                // Copy one byte at a time
                for (var i = 0; i < thatSigBytes; i++) {
                    var thatByte = (thatWords[i >>> 2] >>> (24 - (i % 4) * 8)) & 0xff;
                    thisWords[(thisSigBytes + i) >>> 2] |= thatByte << (24 - ((thisSigBytes + i) % 4) * 8);
                }
            } else {
                // Copy one word at a time
                for (var i = 0; i < thatSigBytes; i += 4) {
                    thisWords[(thisSigBytes + i) >>> 2] = thatWords[i >>> 2];
                }
            }
            this.sigBytes += thatSigBytes;

            // Chainable
            return this;
        },

        /**
         * Removes insignificant bits.
         *
         * @example
         *
         *     wordArray.clamp();
         */
        clamp: function () {
            // Shortcuts
            var words = this.words;
            var sigBytes = this.sigBytes;

            // Clamp
            words[sigBytes >>> 2] &= 0xffffffff << (32 - (sigBytes % 4) * 8);
            words.length = Math.ceil(sigBytes / 4);
        },

        /**
         * Creates a copy of this word array.
         *
         * @return {WordArray} The clone.
         *
         * @example
         *
         *     var clone = wordArray.clone();
         */
        clone: function () {
            var clone = Base.clone.call(this);
            clone.words = this.words.slice(0);

            return clone;
        },

        /**
         * Creates a word array filled with random bytes.
         *
         * @param {number} nBytes The number of random bytes to generate.
         *
         * @return {WordArray} The random word array.
         *
         * @static
         *
         * @example
         *
         *     var wordArray = CryptoJS.lib.WordArray.random(16);
         */
        random: function (nBytes) {
            var words = [];

            for (var i = 0; i < nBytes; i += 4) {
                words.push(cryptoSecureRandomInt());
            }

            return new WordArray.init(words, nBytes);
        }
    });

    /**
     * Encoder namespace.
     */
    var C_enc = C.enc = {};

    /**
     * Hex encoding strategy.
     */
    var Hex = C_enc.Hex = {
        /**
         * Converts a word array to a hex string.
         *
         * @param {WordArray} wordArray The word array.
         *
         * @return {string} The hex string.
         *
         * @static
         *
         * @example
         *
         *     var hexString = CryptoJS.enc.Hex.stringify(wordArray);
         */
        stringify: function (wordArray) {
            // Shortcuts
            var words = wordArray.words;
            var sigBytes = wordArray.sigBytes;

            // Convert
            var hexChars = [];
            for (var i = 0; i < sigBytes; i++) {
                var bite = (words[i >>> 2] >>> (24 - (i % 4) * 8)) & 0xff;
                hexChars.push((bite >>> 4).toString(16));
                hexChars.push((bite & 0x0f).toString(16));
            }

            return hexChars.join('');
        },

        /**
         * Converts a hex string to a word array.
         *
         * @param {string} hexStr The hex string.
         *
         * @return {WordArray} The word array.
         *
         * @static
         *
         * @example
         *
         *     var wordArray = CryptoJS.enc.Hex.parse(hexString);
         */
        parse: function (hexStr) {
            // Shortcut
            var hexStrLength = hexStr.length;

            // Convert
            var words = [];
            for (var i = 0; i < hexStrLength; i += 2) {
                words[i >>> 3] |= parseInt(hexStr.substr(i, 2), 16) << (24 - (i % 8) * 4);
            }

            return new WordArray.init(words, hexStrLength / 2);
        }
    };

    /**
     * Latin1 encoding strategy.
     */
    var Latin1 = C_enc.Latin1 = {
        /**
         * Converts a word array to a Latin1 string.
         *
         * @param {WordArray} wordArray The word array.
         *
         * @return {string} The Latin1 string.
         *
         * @static
         *
         * @example
         *
         *     var latin1String = CryptoJS.enc.Latin1.stringify(wordArray);
         */
        stringify: function (wordArray) {
            // Shortcuts
            var words = wordArray.words;
            var sigBytes = wordArray.sigBytes;

            // Convert
            var latin1Chars = [];
            for (var i = 0; i < sigBytes; i++) {
                var bite = (words[i >>> 2] >>> (24 - (i % 4) * 8)) & 0xff;
                latin1Chars.push(String.fromCharCode(bite));
            }

            return latin1Chars.join('');
        },

        /**
         * Converts a Latin1 string to a word array.
         *
         * @param {string} latin1Str The Latin1 string.
         *
         * @return {WordArray} The word array.
         *
         * @static
         *
         * @example
         *
         *     var wordArray = CryptoJS.enc.Latin1.parse(latin1String);
         */
        parse: function (latin1Str) {
            // Shortcut
            var latin1StrLength = latin1Str.length;

            // Convert
            var words = [];
            for (var i = 0; i < latin1StrLength; i++) {
                words[i >>> 2] |= (latin1Str.charCodeAt(i) & 0xff) << (24 - (i % 4) * 8);
            }

            return new WordArray.init(words, latin1StrLength);
        }
    };

    /**
     * UTF-8 encoding strategy.
     */
    var Utf8 = C_enc.Utf8 = {
        /**
         * Converts a word array to a UTF-8 string.
         *
         * @param {WordArray} wordArray The word array.
         *
         * @return {string} The UTF-8 string.
         *
         * @static
         *
         * @example
         *
         *     var utf8String = CryptoJS.enc.Utf8.stringify(wordArray);
         */
        stringify: function (wordArray) {
            try {
                return decodeURIComponent(escape(Latin1.stringify(wordArray)));
            } catch (e) {
                throw new Error('Malformed UTF-8 data');
            }
        },

        /**
         * Converts a UTF-8 string to a word array.
         *
         * @param {string} utf8Str The UTF-8 string.
         *
         * @return {WordArray} The word array.
         *
         * @static
         *
         * @example
         *
         *     var wordArray = CryptoJS.enc.Utf8.parse(utf8String);
         */
        parse: function (utf8Str) {
            return Latin1.parse(unescape(encodeURIComponent(utf8Str)));
        }
    };

    /**
     * Abstract buffered block algorithm template.
     *
     * The property blockSize must be implemented in a concrete subtype.
     *
     * @property {number} _minBufferSize The number of blocks that should be kept unprocessed in the buffer. Default: 0
     */
    var BufferedBlockAlgorithm = C_lib.BufferedBlockAlgorithm = Base.extend({
        /**
         * Resets this block algorithm's data buffer to its initial state.
         *
         * @example
         *
         *     bufferedBlockAlgorithm.reset();
         */
        reset: function () {
            // Initial values
            this._data = new WordArray.init();
            this._nDataBytes = 0;
        },

        /**
         * Adds new data to this block algorithm's buffer.
         *
         * @param {WordArray|string} data The data to append. Strings are converted to a WordArray using UTF-8.
         *
         * @example
         *
         *     bufferedBlockAlgorithm._append('data');
         *     bufferedBlockAlgorithm._append(wordArray);
         */
        _append: function (data) {
            // Convert string to WordArray, else assume WordArray already
            if (typeof data == 'string') {
                data = Utf8.parse(data);
            }

            // Append
            this._data.concat(data);
            this._nDataBytes += data.sigBytes;
        },

        /**
         * Processes available data blocks.
         *
         * This method invokes _doProcessBlock(offset), which must be implemented by a concrete subtype.
         *
         * @param {boolean} doFlush Whether all blocks and partial blocks should be processed.
         *
         * @return {WordArray} The processed data.
         *
         * @example
         *
         *     var processedData = bufferedBlockAlgorithm._process();
         *     var processedData = bufferedBlockAlgorithm._process(!!'flush');
         */
        _process: function (doFlush) {
            var processedWords;

            // Shortcuts
            var data = this._data;
            var dataWords = data.words;
            var dataSigBytes = data.sigBytes;
            var blockSize = this.blockSize;
            var blockSizeBytes = blockSize * 4;

            // Count blocks ready
            var nBlocksReady = dataSigBytes / blockSizeBytes;
            if (doFlush) {
                // Round up to include partial blocks
                nBlocksReady = Math.ceil(nBlocksReady);
            } else {
                // Round down to include only full blocks,
                // less the number of blocks that must remain in the buffer
                nBlocksReady = Math.max((nBlocksReady | 0) - this._minBufferSize, 0);
            }

            // Count words ready
            var nWordsReady = nBlocksReady * blockSize;

            // Count bytes ready
            var nBytesReady = Math.min(nWordsReady * 4, dataSigBytes);

            // Process blocks
            if (nWordsReady) {
                for (var offset = 0; offset < nWordsReady; offset += blockSize) {
                    // Perform concrete-algorithm logic
                    this._doProcessBlock(dataWords, offset);
                }

                // Remove processed words
                processedWords = dataWords.splice(0, nWordsReady);
                data.sigBytes -= nBytesReady;
            }

            // Return processed words
            return new WordArray.init(processedWords, nBytesReady);
        },

        /**
         * Creates a copy of this object.
         *
         * @return {Object} The clone.
         *
         * @example
         *
         *     var clone = bufferedBlockAlgorithm.clone();
         */
        clone: function () {
            var clone = Base.clone.call(this);
            clone._data = this._data.clone();

            return clone;
        },

        _minBufferSize: 0
    });

    /**
     * Abstract hasher template.
     *
     * @property {number} blockSize The number of 32-bit words this hasher operates on. Default: 16 (512 bits)
     */
    var Hasher = C_lib.Hasher = BufferedBlockAlgorithm.extend({
        /**
         * Configuration options.
         */
        cfg: Base.extend(),

        /**
         * Initializes a newly created hasher.
         *
         * @param {Object} cfg (Optional) The configuration options to use for this hash computation.
         *
         * @example
         *
         *     var hasher = CryptoJS.algo.SHA256.create();
         */
        init: function (cfg) {
            // Apply config defaults
            this.cfg = this.cfg.extend(cfg);

            // Set initial values
            this.reset();
        },

        /**
         * Resets this hasher to its initial state.
         *
         * @example
         *
         *     hasher.reset();
         */
        reset: function () {
            // Reset data buffer
            BufferedBlockAlgorithm.reset.call(this);

            // Perform concrete-hasher logic
            this._doReset();
        },

        /**
         * Updates this hasher with a message.
         *
         * @param {WordArray|string} messageUpdate The message to append.
         *
         * @return {Hasher} This hasher.
         *
         * @example
         *
         *     hasher.update('message');
         *     hasher.update(wordArray);
         */
        update: function (messageUpdate) {
            // Append
            this._append(messageUpdate);

            // Update the hash
            this._process();

            // Chainable
            return this;
        },

        /**
         * Finalizes the hash computation.
         * Note that the finalize operation is effectively a destructive, read-once operation.
         *
         * @param {WordArray|string} messageUpdate (Optional) A final message update.
         *
         * @return {WordArray} The hash.
         *
         * @example
         *
         *     var hash = hasher.finalize();
         *     var hash = hasher.finalize('message');
         *     var hash = hasher.finalize(wordArray);
         */
        finalize: function (messageUpdate) {
            // Final message update
            if (messageUpdate) {
                this._append(messageUpdate);
            }

            // Perform concrete-hasher logic
            var hash = this._doFinalize();

            return hash;
        },

        blockSize: 512/32,

        /**
         * Creates a shortcut function to a hasher's object interface.
         *
         * @param {Hasher} hasher The hasher to create a helper for.
         *
         * @return {Function} The shortcut function.
         *
         * @static
         *
         * @example
         *
         *     var SHA256 = CryptoJS.lib.Hasher._createHelper(CryptoJS.algo.SHA256);
         */
        _createHelper: function (hasher) {
            return function (message, cfg) {
                return new hasher.init(cfg).finalize(message);
            };
        },

        /**
         * Creates a shortcut function to the HMAC's object interface.
         *
         * @param {Hasher} hasher The hasher to use in this HMAC helper.
         *
         * @return {Function} The shortcut function.
         *
         * @static
         *
         * @example
         *
         *     var HmacSHA256 = CryptoJS.lib.Hasher._createHmacHelper(CryptoJS.algo.SHA256);
         */
        _createHmacHelper: function (hasher) {
            return function (message, key) {
                return new C_algo.HMAC.init(hasher, key).finalize(message);
            };
        }
    });

    /**
     * Algorithm namespace.
     */
    var C_algo = C.algo = {};

    return C;
}(Math));