说明：  在实现本实例之前先来简要了解一下加密的概念，加密是指通过 某种特殊的方法，更改已有信息的内容，使得未授权的用户即使得到 了加密信息，如果没有正确解密的方法，也无法得到信息的内容。谈 到加密的话题，一些读者一定非常感兴趣，而且会联想到复杂的加密 算法，本实例主要使用异或“^”运算符简单地实现了对数字加密的 功能
(Take a brief look at the concept of encryption before implementing this example, encryption is defined by some special way, has changed the content of the information, the unauthorized users even get the encrypted information, if there is no correct decryption method can not get the information. When it comes to the topic of encryption, some readers will be very interested, and will associate the complex encryption algorithm. This example mainly uses XOR "^" operator to realize the function of digital encryption simply.)