说明：  本文是一篇讨论关于常用文件加密解密算法的毕业设计论文，它详细的讲述了文件加密解密算法实现的过程中所用到的方法、技术。
(This article is a discussion about common file encryption and decryption algorithm design graduate thesis in detail about the methods, techniques used in the process of file encryption and decryption algorithm.)