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/**
* ECBMode
*
* An ActionScript 3 implementation of the ECB confidentiality mode
* Copyright (c) 2007 Henri Torgemane
*
* See LICENSE.txt for full license information.
*/
package com.hurlant.crypto.symmetric
{
import flash.utils.ByteArray;
import com.hurlant.util.Memory;
import com.hurlant.util.Hex;
/**
* ECB mode.
* This uses a padding and a symmetric key.
* If no padding is given, PKCS#5 is used.
*/
public class ECBMode implements IMode, ICipher
{
private var key:ISymmetricKey;
private var padding:IPad;
public function ECBMode(key:ISymmetricKey, padding:IPad = null) {
this.key = key;
if (padding == null) {
padding = new PKCS5(key.getBlockSize());
} else {
padding.setBlockSize(key.getBlockSize());
}
this.padding = padding;
}
public function getBlockSize():uint {
return key.getBlockSize();
}
public function encrypt(src:ByteArray):void {
padding.pad(src);
src.position = 0;
var blockSize:uint = key.getBlockSize();
var tmp:ByteArray = new ByteArray;
var dst:ByteArray = new ByteArray;
for (var i:uint=0;i<src.length;i+=blockSize) {
tmp.length=0;
src.readBytes(tmp, 0, blockSize);
key.encrypt(tmp);
dst.writeBytes(tmp);
}
src.length=0;
src.writeBytes(dst);
}
public function decrypt(src:ByteArray):void {
src.position = 0;
var blockSize:uint = key.getBlockSize();
// sanity check.
if (src.length%blockSize!=0) {
throw new Error("ECB mode cipher length must be a multiple of blocksize "+blockSize);
}
var tmp:ByteArray = new ByteArray;
var dst:ByteArray = new ByteArray;
for (var i:uint=0;i<src.length;i+=blockSize) {
tmp.length=0;
src.readBytes(tmp, 0, blockSize);
key.decrypt(tmp);
dst.writeBytes(tmp);
}
padding.unpad(dst);
src.length=0;
src.writeBytes(dst);
}
public function dispose():void {
key.dispose();
key = null;
padding = null;
Memory.gc();
}
public function toString():String {
return key.toString()+"-ecb";
}
}
}
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