78 lines
2.0 KiB
JavaScript
78 lines
2.0 KiB
JavaScript
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;(function (root, factory, undef) {
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if (typeof exports === "object") {
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// CommonJS
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module.exports = exports = factory(require("./core"), require("./cipher-core"));
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}
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else if (typeof define === "function" && define.amd) {
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// AMD
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define(["./core", "./cipher-core"], factory);
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}
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else {
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// Global (browser)
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factory(root.CryptoJS);
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}
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}(this, function (CryptoJS) {
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/**
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* Cipher Feedback block mode.
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*/
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CryptoJS.mode.CFB = (function () {
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var CFB = CryptoJS.lib.BlockCipherMode.extend();
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CFB.Encryptor = CFB.extend({
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processBlock: function (words, offset) {
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// Shortcuts
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var cipher = this._cipher;
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var blockSize = cipher.blockSize;
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generateKeystreamAndEncrypt.call(this, words, offset, blockSize, cipher);
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// Remember this block to use with next block
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this._prevBlock = words.slice(offset, offset + blockSize);
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}
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});
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CFB.Decryptor = CFB.extend({
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processBlock: function (words, offset) {
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// Shortcuts
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var cipher = this._cipher;
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var blockSize = cipher.blockSize;
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// Remember this block to use with next block
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var thisBlock = words.slice(offset, offset + blockSize);
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generateKeystreamAndEncrypt.call(this, words, offset, blockSize, cipher);
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// This block becomes the previous block
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this._prevBlock = thisBlock;
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}
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});
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function generateKeystreamAndEncrypt(words, offset, blockSize, cipher) {
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// Shortcut
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var iv = this._iv;
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// Generate keystream
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if (iv) {
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var keystream = iv.slice(0);
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// Remove IV for subsequent blocks
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this._iv = undefined;
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} else {
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var keystream = this._prevBlock;
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}
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cipher.encryptBlock(keystream, 0);
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// Encrypt
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for (var i = 0; i < blockSize; i++) {
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words[offset + i] ^= keystream[i];
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}
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}
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return CFB;
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}());
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return CryptoJS.mode.CFB;
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}));
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