通过设计自己的用户名和密码，隐藏自己要打开的文件，这个文件需要是excel的，实现对excel的加密功能-By designing your own user name and password, and hide their want to open the file, this file needs to be excel, and achieve excel encryption capabilities

DES加密解密用于文件的普通加密，可用于学习。-DES encryption decryption the ordinary for file encryption