/**

 * CBCMode

 * 

 * An ActionScript 3 implementation of the CBC confidentiality mode

 * Copyright (c) 2007 Henri Torgemane

 * 

 * See LICENSE.txt for full license information.

 */

package com.hurlant.crypto.symmetric

{

	import flash.utils.ByteArray;

	

	/**

	 * CBC confidentiality mode. why not.

	 */

	public class CBCMode extends IVMode implements IMode

	{

		

		public function CBCMode(key:ISymmetricKey, padding:IPad = null) {

			super(key, padding);

		}



		public function encrypt(src:ByteArray):void {

			padding.pad(src);

			var vector:ByteArray = getIV4e();

			for (var i:uint=0;i<src.length;i+=blockSize) {

				for (var j:uint=0;j<blockSize;j++) {

					src[i+j] ^= vector[j];

				}

				key.encrypt(src, i);

				vector.position=0;

				vector.writeBytes(src, i, blockSize);

			}

		}

		public function decrypt(src:ByteArray):void {

			var vector:ByteArray = getIV4d();

			var tmp:ByteArray = new ByteArray;

			for (var i:uint=0;i<src.length;i+=blockSize) {

				tmp.position=0;

				tmp.writeBytes(src, i, blockSize);

				key.decrypt(src, i);

				for (var j:uint=0;j<blockSize;j++) {

					src[i+j] ^= vector[j];

				}

				vector.position=0;

				vector.writeBytes(tmp, 0, blockSize);

			}

			padding.unpad(src);

		}

		

		public function toString():String {

			return key.toString()+"-cbc";

		}

	}

}