관리-도구

편집 파일: mode-cfb.js

;(function (root, factory, undef) {
	if (typeof exports === "object") {
		// CommonJS
		module.exports = exports = factory(require("./core"), require("./cipher-core"));
	}
	else if (typeof define === "function" && define.amd) {
		// AMD
		define(["./core", "./cipher-core"], factory);
	}
	else {
		// Global (browser)
		factory(root.CryptoJS);
	}
}(this, function (CryptoJS) {

/**
	 * 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;
	}());

return CryptoJS.mode.CFB;

}));