/**
 * 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";
        }
    }
}