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/**
* CFBMode
*
* An ActionScript 3 implementation of the CFB confidentiality mode
* Copyright (c) 2007 Henri Torgemane
*
* See LICENSE.txt for full license information.
*/
package com.hurlant.crypto.symmetric
{
import flash.utils.ByteArray;
/**
* This is the "full" CFB.
* CFB1 and CFB8 are hiding somewhere else.
*
* Note: The constructor accepts an optional padding argument, but ignores it otherwise.
*/
public class CFBMode extends IVMode implements IMode
{
public function CFBMode(key:ISymmetricKey, padding:IPad = null) {
super(key,null);
}
public function encrypt(src:ByteArray):void
{
var l:uint = src.length;
var vector:ByteArray = getIV4e();
for (var i:uint=0;i<src.length;i+=blockSize) {
key.encrypt(vector);
var chunk:uint = (i+blockSize<l)?blockSize:l-i;
for (var j:uint=0;j<chunk;j++) {
src[i+j] ^= vector[j];
}
vector.position=0;
vector.writeBytes(src, i, chunk);
}
}
public function decrypt(src:ByteArray):void
{
var l:uint = src.length;
var vector:ByteArray = getIV4d();
var tmp:ByteArray = new ByteArray;
for (var i:uint=0;i<src.length;i+=blockSize) {
key.encrypt(vector);
var chunk:uint = (i+blockSize<l)?blockSize:l-i;
tmp.position=0;
tmp.writeBytes(src, i, chunk);
for (var j:uint=0;j<chunk;j++) {
src[i+j] ^= vector[j];
}
vector.position=0;
vector.writeBytes(tmp);
}
}
public function toString():String {
return key.toString()+"-cfb";
}
}
}
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