61 lines
1.5 KiB
ActionScript
61 lines
1.5 KiB
ActionScript
/**
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* CFB8Mode
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*
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* An ActionScript 3 implementation of the CFB-8 confidentiality mode
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* Copyright (c) 2007 Henri Torgemane
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*
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* See LICENSE.txt for full license information.
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*/
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package com.hurlant.crypto.symmetric
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{
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import com.hurlant.crypto.tests.TestCase;
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import flash.utils.ByteArray;
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/**
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*
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* Note: The constructor accepts an optional padding argument, but ignores it otherwise.
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*/
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public class CFB8Mode extends IVMode implements IMode
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{
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public function CFB8Mode(key:ISymmetricKey, padding:IPad = null) {
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super(key, null);
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}
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public function encrypt(src:ByteArray):void {
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var vector:ByteArray = getIV4e();
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var tmp:ByteArray = new ByteArray;
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for (var i:uint=0;i<src.length;i++) {
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tmp.position = 0;
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tmp.writeBytes(vector);
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key.encrypt(vector);
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src[i] ^= vector[0];
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// rotate
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for (var j:uint=0;j<blockSize-1;j++) {
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vector[j] = tmp[j+1];
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}
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vector[blockSize-1] = src[i];
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}
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}
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public function decrypt(src:ByteArray):void {
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var vector:ByteArray = getIV4d();
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var tmp:ByteArray = new ByteArray;
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for (var i:uint=0;i<src.length;i++) {
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var c:uint = src[i];
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tmp.position = 0;
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tmp.writeBytes(vector); // I <- tmp
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key.encrypt(vector); // O <- vector
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src[i] ^= vector[0];
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// rotate
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for (var j:uint=0;j<blockSize-1;j++) {
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vector[j] = tmp[j+1];
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}
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vector[blockSize-1] = c;
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}
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}
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public function toString():String {
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return key.toString()+"-cfb8";
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}
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}
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} |