分别实现DES的加密和解密，该程序加密的对象为8位字符串，加密后显示的结果为将64比特转为字符串的形式。加密的正确性可通过解密的结果来验证。-This program aims to encrypt and decrypt DES respectively, and the encrypted object of the program is the 8-bit string, i.e. converting the 64 bits into the form of strings. The validity of the encrypting could be verified by the results of the decrypting.