简易的rc4加密法演示程序。rc4在加密过程中会改变key，因此用同一个rc4类实例不能对一个字符串同时加密和解密。详情请看代码。

jackyzoufeng@hotmail.com-simple rc4 cryptography demonstration program. Rc4 in the process of encryption key will change. So using the same example of a type not rc4 to a string while encryption and decryption. For more information, please see code. Jackyzoufeng@hotmail.com