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source/com/hurlant/crypto/symmetric/SimpleIVMode.as

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+/**
+ * SimpleIVMode
+ * 
+ * A convenience class that automatically places the IV
+ * at the beginning of the encrypted stream, so it doesn't have to
+ * be handled explicitely.
+ * 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;
+	
+	public class SimpleIVMode implements IMode, ICipher
+	{
+		protected var mode:IVMode;
+		protected var cipher:ICipher;
+		
+		public function SimpleIVMode(mode:IVMode) {
+			this.mode = mode;
+			cipher = mode as ICipher;
+		}
+		
+		public function getBlockSize():uint {
+			return mode.getBlockSize();
+		}
+		
+		public function dispose():void {
+			mode.dispose();
+			mode = null;
+			cipher = null;
+			Memory.gc();
+		}
+		
+		public function encrypt(src:ByteArray):void {
+			cipher.encrypt(src);
+			var tmp:ByteArray = new ByteArray;
+			tmp.writeBytes(mode.IV);
+			tmp.writeBytes(src);
+			src.position=0;
+			src.writeBytes(tmp);
+		}
+		
+		public function decrypt(src:ByteArray):void {
+			var tmp:ByteArray = new ByteArray;
+			tmp.writeBytes(src, 0, getBlockSize());
+			mode.IV = tmp;
+			tmp = new ByteArray;
+			tmp.writeBytes(src, getBlockSize());
+			cipher.decrypt(tmp);
+			src.length=0;
+			src.writeBytes(tmp);
+		}
+		public function toString():String {
+			return "simple-"+cipher.toString();
+		}
+	}
+}