add js library files

lib/BlockModes.js

@@ -0,0 +1,378 @@
+/*!
+ * Crypto-JS contribution from Simon Greatrix
+ */
+
+(function(){
+
+var C = (typeof window === 'undefined') ? require('./Crypto').Crypto : window.Crypto;
+
+// Create pad namespace
+var C_pad = C.pad = {};
+
+// Calculate the number of padding bytes required.
+function _requiredPadding(cipher, message) {
+    var blockSizeInBytes = cipher._blocksize * 4;
+    var reqd = blockSizeInBytes - message.length % blockSizeInBytes;
+    return reqd;
+};
+
+// Remove padding when the final byte gives the number of padding bytes.
+var _unpadLength = function (message) {
+        var pad = message.pop();
+        for (var i = 1; i < pad; i++) {
+            message.pop();
+        }
+    };
+
+// No-operation padding, used for stream ciphers
+C_pad.NoPadding = {
+        pad : function (cipher,message) {},
+        unpad : function (message) {}
+    };
+
+// Zero Padding.
+//
+// If the message is not an exact number of blocks, the final block is
+// completed with 0x00 bytes. There is no unpadding.
+C_pad.ZeroPadding = {
+    pad : function (cipher, message) {
+        var blockSizeInBytes = cipher._blocksize * 4;
+        var reqd = message.length % blockSizeInBytes;
+        if( reqd!=0 ) {
+            for(reqd = blockSizeInBytes - reqd; reqd>0; reqd--) {
+                message.push(0x00);
+            }
+        }
+    },
+
+    unpad : function (message) {}
+};
+
+// ISO/IEC 7816-4 padding.
+//
+// Pads the plain text with an 0x80 byte followed by as many 0x00
+// bytes are required to complete the block.
+C_pad.iso7816 = {
+    pad : function (cipher, message) {
+        var reqd = _requiredPadding(cipher, message);
+        message.push(0x80);
+        for (; reqd > 1; reqd--) {
+            message.push(0x00);
+        }
+    },
+
+    unpad : function (message) {
+        while (message.pop() != 0x80) {}
+    }
+};
+
+// ANSI X.923 padding
+//
+// The final block is padded with zeros except for the last byte of the
+// last block which contains the number of padding bytes.
+C_pad.ansix923 = {
+    pad : function (cipher, message) {
+        var reqd = _requiredPadding(cipher, message);
+        for (var i = 1; i < reqd; i++) {
+            message.push(0x00);
+        }
+        message.push(reqd);
+    },
+
+    unpad : _unpadLength
+};
+
+// ISO 10126
+//
+// The final block is padded with random bytes except for the last
+// byte of the last block which contains the number of padding bytes.
+C_pad.iso10126 = {
+    pad : function (cipher, message) {
+        var reqd = _requiredPadding(cipher, message);
+        for (var i = 1; i < reqd; i++) {
+            message.push(Math.floor(Math.random() * 256));
+        }
+        message.push(reqd);
+    },
+
+    unpad : _unpadLength
+};
+
+// PKCS7 padding
+//
+// PKCS7 is described in RFC 5652. Padding is in whole bytes. The
+// value of each added byte is the number of bytes that are added,
+// i.e. N bytes, each of value N are added.
+C_pad.pkcs7 = {
+    pad : function (cipher, message) {
+        var reqd = _requiredPadding(cipher, message);
+        for (var i = 0; i < reqd; i++) {
+            message.push(reqd);
+        }
+    },
+
+    unpad : _unpadLength
+};
+
+// Create mode namespace
+var C_mode = C.mode = {};
+
+/**
+ * Mode base "class".
+ */
+var Mode = C_mode.Mode = function (padding) {
+    if (padding) {
+        this._padding = padding;
+    }
+};
+
+Mode.prototype = {
+    encrypt: function (cipher, m, iv) {
+        this._padding.pad(cipher, m);
+        this._doEncrypt(cipher, m, iv);
+    },
+
+    decrypt: function (cipher, m, iv) {
+        this._doDecrypt(cipher, m, iv);
+        this._padding.unpad(m);
+    },
+
+    // Default padding
+    _padding: C_pad.iso7816
+};
+
+
+/**
+ * Electronic Code Book mode.
+ * 
+ * ECB applies the cipher directly against each block of the input.
+ * 
+ * ECB does not require an initialization vector.
+ */
+var ECB = C_mode.ECB = function () {
+    // Call parent constructor
+    Mode.apply(this, arguments);
+};
+
+// Inherit from Mode
+var ECB_prototype = ECB.prototype = new Mode;
+
+// Concrete steps for Mode template
+ECB_prototype._doEncrypt = function (cipher, m, iv) {
+    var blockSizeInBytes = cipher._blocksize * 4;
+    // Encrypt each block
+    for (var offset = 0; offset < m.length; offset += blockSizeInBytes) {
+        cipher._encryptblock(m, offset);
+    }
+};
+ECB_prototype._doDecrypt = function (cipher, c, iv) {
+    var blockSizeInBytes = cipher._blocksize * 4;
+    // Decrypt each block
+    for (var offset = 0; offset < c.length; offset += blockSizeInBytes) {
+        cipher._decryptblock(c, offset);
+    }
+};
+
+// ECB never uses an IV
+ECB_prototype.fixOptions = function (options) {
+    options.iv = [];
+};
+
+
+/**
+ * Cipher block chaining
+ * 
+ * The first block is XORed with the IV. Subsequent blocks are XOR with the
+ * previous cipher output.
+ */
+var CBC = C_mode.CBC = function () {
+    // Call parent constructor
+    Mode.apply(this, arguments);
+};
+
+// Inherit from Mode
+var CBC_prototype = CBC.prototype = new Mode;
+
+// Concrete steps for Mode template
+CBC_prototype._doEncrypt = function (cipher, m, iv) {
+    var blockSizeInBytes = cipher._blocksize * 4;
+
+    // Encrypt each block
+    for (var offset = 0; offset < m.length; offset += blockSizeInBytes) {
+        if (offset == 0) {
+            // XOR first block using IV
+            for (var i = 0; i < blockSizeInBytes; i++)
+            m[i] ^= iv[i];
+        } else {
+            // XOR this block using previous crypted block
+            for (var i = 0; i < blockSizeInBytes; i++)
+            m[offset + i] ^= m[offset + i - blockSizeInBytes];
+        }
+        // Encrypt block
+        cipher._encryptblock(m, offset);
+    }
+};
+CBC_prototype._doDecrypt = function (cipher, c, iv) {
+    var blockSizeInBytes = cipher._blocksize * 4;
+
+    // At the start, the previously crypted block is the IV
+    var prevCryptedBlock = iv;
+
+    // Decrypt each block
+    for (var offset = 0; offset < c.length; offset += blockSizeInBytes) {
+        // Save this crypted block
+        var thisCryptedBlock = c.slice(offset, offset + blockSizeInBytes);
+        // Decrypt block
+        cipher._decryptblock(c, offset);
+        // XOR decrypted block using previous crypted block
+        for (var i = 0; i < blockSizeInBytes; i++) {
+            c[offset + i] ^= prevCryptedBlock[i];
+        }
+        prevCryptedBlock = thisCryptedBlock;
+    }
+};
+
+
+/**
+ * Cipher feed back
+ * 
+ * The cipher output is XORed with the plain text to produce the cipher output,
+ * which is then fed back into the cipher to produce a bit pattern to XOR the
+ * next block with.
+ * 
+ * This is a stream cipher mode and does not require padding.
+ */
+var CFB = C_mode.CFB = function () {
+    // Call parent constructor
+    Mode.apply(this, arguments);
+};
+
+// Inherit from Mode
+var CFB_prototype = CFB.prototype = new Mode;
+
+// Override padding
+CFB_prototype._padding = C_pad.NoPadding;
+
+// Concrete steps for Mode template
+CFB_prototype._doEncrypt = function (cipher, m, iv) {
+    var blockSizeInBytes = cipher._blocksize * 4,
+        keystream = iv.slice(0);
+
+    // Encrypt each byte
+    for (var i = 0; i < m.length; i++) {
+
+        var j = i % blockSizeInBytes;
+        if (j == 0) cipher._encryptblock(keystream, 0);
+
+        m[i] ^= keystream[j];
+        keystream[j] = m[i];
+    }
+};
+CFB_prototype._doDecrypt = function (cipher, c, iv) {
+    var blockSizeInBytes = cipher._blocksize * 4,
+        keystream = iv.slice(0);
+
+    // Encrypt each byte
+    for (var i = 0; i < c.length; i++) {
+
+        var j = i % blockSizeInBytes;
+        if (j == 0) cipher._encryptblock(keystream, 0);
+
+        var b = c[i];
+        c[i] ^= keystream[j];
+        keystream[j] = b;
+    }
+};
+
+
+/**
+ * Output feed back
+ * 
+ * The cipher repeatedly encrypts its own output. The output is XORed with the
+ * plain text to produce the cipher text.
+ * 
+ * This is a stream cipher mode and does not require padding.
+ */
+var OFB = C_mode.OFB = function () {
+    // Call parent constructor
+    Mode.apply(this, arguments);
+};
+
+// Inherit from Mode
+var OFB_prototype = OFB.prototype = new Mode;
+
+// Override padding
+OFB_prototype._padding = C_pad.NoPadding;
+
+// Concrete steps for Mode template
+OFB_prototype._doEncrypt = function (cipher, m, iv) {
+
+    var blockSizeInBytes = cipher._blocksize * 4,
+        keystream = iv.slice(0);
+
+    // Encrypt each byte
+    for (var i = 0; i < m.length; i++) {
+
+        // Generate keystream
+        if (i % blockSizeInBytes == 0)
+            cipher._encryptblock(keystream, 0);
+
+        // Encrypt byte
+        m[i] ^= keystream[i % blockSizeInBytes];
+
+    }
+};
+OFB_prototype._doDecrypt = OFB_prototype._doEncrypt;
+
+/**
+ * Counter
+ * @author Gergely Risko
+ *
+ * After every block the last 4 bytes of the IV is increased by one
+ * with carry and that IV is used for the next block.
+ *
+ * This is a stream cipher mode and does not require padding.
+ */
+var CTR = C_mode.CTR = function () {
+    // Call parent constructor
+    Mode.apply(this, arguments);
+};
+
+// Inherit from Mode
+var CTR_prototype = CTR.prototype = new Mode;
+
+// Override padding
+CTR_prototype._padding = C_pad.NoPadding;
+
+CTR_prototype._doEncrypt = function (cipher, m, iv) {
+    var blockSizeInBytes = cipher._blocksize * 4;
+    var counter = iv.slice(0);
+
+    for (var i = 0; i < m.length;) {
+        // do not lose iv
+        var keystream = counter.slice(0);
+
+        // Generate keystream for next block
+        cipher._encryptblock(keystream, 0);
+
+        // XOR keystream with block
+        for (var j = 0; i < m.length && j < blockSizeInBytes; j++, i++) {
+            m[i] ^= keystream[j];
+        }
+
+        // Increase counter
+        if(++(counter[blockSizeInBytes-1]) == 256) {
+            counter[blockSizeInBytes-1] = 0;
+            if(++(counter[blockSizeInBytes-2]) == 256) {
+                counter[blockSizeInBytes-2] = 0;
+                if(++(counter[blockSizeInBytes-3]) == 256) {
+                    counter[blockSizeInBytes-3] = 0;
+                    ++(counter[blockSizeInBytes-4]);
+                }
+            }
+        }
+    }
+};
+CTR_prototype._doDecrypt = CTR_prototype._doEncrypt;
+
+})();