private function decode(data:ByteArray):ByteArray{
			var dest:ByteArray = new ByteArray();
			var index:int;
			var key:String = "I‘m a big big girl with a big big hole";
			var count:int;
			var i:int;
			while (i < data.length) {
				if (index>= key.length){
					index = 0;
					count++;
					if (count >= 40){
						dest.writeBytes(data, (40 * key.length), (data.length - (40 * key.length)));
						break;
					};
				};
				dest.writeByte((data[i] - key.charCodeAt(index)));
				i++;
				index++;
			};
			dest.position = 0;
			return dest;
		}
		
		private var key:String = ‘helloworld‘;
		private function decode2(src:ByteArray, type:int):ByteArray{
			var dest:ByteArray = new ByteArray();
			var index:int;
			var count:int;
			var i:int;
			while (i < src.length) {
				if (index >= key.length){
					index = 0;
					count++;
					if (count >= 50){
						dest.writeBytes(src, (50 * key.length), (src.length - (50 * key.length)));
						break;
					};
				};
				if (type == 0){
					dest.writeByte((src[i] + key.charCodeAt(index)));
				} else {
					if (type == 1){
						dest.writeByte((src[i] - key.charCodeAt(index)));
					};
				};
				i++;
				index++;
			};
			dest.position = 0;
			return (dest);
		}
原文地址:http://www.cnblogs.com/zc22/p/3809965.html