65 lines
1.8 KiB
JavaScript
65 lines
1.8 KiB
JavaScript
/*
|
|
CryptoJS v3.1.2
|
|
code.google.com/p/crypto-js
|
|
(c) 2009-2013 by Jeff Mott. All rights reserved.
|
|
code.google.com/p/crypto-js/wiki/License
|
|
*/
|
|
/**
|
|
* Cipher Feedback block mode.
|
|
*/
|
|
CryptoJS.mode.CFB = (function () {
|
|
var CFB = CryptoJS.lib.BlockCipherMode.extend();
|
|
|
|
CFB.Encryptor = CFB.extend({
|
|
processBlock: function (words, offset) {
|
|
// Shortcuts
|
|
var cipher = this._cipher;
|
|
var blockSize = cipher.blockSize;
|
|
|
|
generateKeystreamAndEncrypt.call(this, words, offset, blockSize, cipher);
|
|
|
|
// Remember this block to use with next block
|
|
this._prevBlock = words.slice(offset, offset + blockSize);
|
|
}
|
|
});
|
|
|
|
CFB.Decryptor = CFB.extend({
|
|
processBlock: function (words, offset) {
|
|
// Shortcuts
|
|
var cipher = this._cipher;
|
|
var blockSize = cipher.blockSize;
|
|
|
|
// Remember this block to use with next block
|
|
var thisBlock = words.slice(offset, offset + blockSize);
|
|
|
|
generateKeystreamAndEncrypt.call(this, words, offset, blockSize, cipher);
|
|
|
|
// This block becomes the previous block
|
|
this._prevBlock = thisBlock;
|
|
}
|
|
});
|
|
|
|
function generateKeystreamAndEncrypt(words, offset, blockSize, cipher) {
|
|
// Shortcut
|
|
var iv = this._iv;
|
|
|
|
// Generate keystream
|
|
if (iv) {
|
|
var keystream = iv.slice(0);
|
|
|
|
// Remove IV for subsequent blocks
|
|
this._iv = undefined;
|
|
} else {
|
|
var keystream = this._prevBlock;
|
|
}
|
|
cipher.encryptBlock(keystream, 0);
|
|
|
|
// Encrypt
|
|
for (var i = 0; i < blockSize; i++) {
|
|
words[offset + i] ^= keystream[i];
|
|
}
|
|
}
|
|
|
|
return CFB;
|
|
}());
|