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

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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
+	{
+		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());
+			}
+			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";
+		}
+	}
+}