64 lines
1.5 KiB
ActionScript
64 lines
1.5 KiB
ActionScript
/**
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* CFBMode
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*
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* An ActionScript 3 implementation of the CFB 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 flash.utils.ByteArray;
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/**
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* This is the "full" CFB.
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* CFB1 and CFB8 are hiding somewhere else.
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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 CFBMode extends IVMode implements IMode
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{
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public function CFBMode(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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{
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var l:uint = src.length;
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var vector:ByteArray = getIV4e();
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for (var i:uint=0;i<src.length;i+=blockSize) {
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key.encrypt(vector);
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var chunk:uint = (i+blockSize<l)?blockSize:l-i;
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for (var j:uint=0;j<chunk;j++) {
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src[i+j] ^= vector[j];
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}
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vector.position=0;
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vector.writeBytes(src, i, chunk);
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}
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}
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public function decrypt(src:ByteArray):void
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{
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var l:uint = src.length;
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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+=blockSize) {
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key.encrypt(vector);
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var chunk:uint = (i+blockSize<l)?blockSize:l-i;
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tmp.position=0;
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tmp.writeBytes(src, i, chunk);
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for (var j:uint=0;j<chunk;j++) {
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src[i+j] ^= vector[j];
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}
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vector.position=0;
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vector.writeBytes(tmp);
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}
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}
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public function toString():String {
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return key.toString()+"-cfb";
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}
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}
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} |