/js/lib/Socket.IO-node/support/socket.io-client/lib/vendor/web-socket-js/flash-src/com/hurlant/crypto/symmetric/OFBMode.as

/**

 * OFBMode

 * 

 * An ActionScript 3 implementation of the OFB confidentiality mode

 * Copyright (c) 2007 Henri Torgemane

 * 

 * See LICENSE.txt for full license information.

 */

package com.hurlant.crypto.symmetric

{

	import flash.utils.ByteArray;



	public class OFBMode extends IVMode implements IMode

	{

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

		{

			super(key, null);

		}

		

		public function encrypt(src:ByteArray):void

		{

			var vector:ByteArray = getIV4e();

			core(src, vector);

		}

		

		public function decrypt(src:ByteArray):void

		{

			var vector:ByteArray = getIV4d();

			core(src, vector);

		}

		

		private function core(src:ByteArray, iv:ByteArray):void { 

			var l:uint = src.length;

			var tmp:ByteArray = new ByteArray;

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

				key.encrypt(iv);

				tmp.position=0;

				tmp.writeBytes(iv);

				var chunk:uint = (i+blockSize<l)?blockSize:l-i;

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

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

				}

				iv.position=0;

				iv.writeBytes(tmp);

			}

		}

		public function toString():String {

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

		}

		

	}

}