功能如下： 实现对文本文件的联合加密，用DES对文本文档进行加密，利用RSA对DES的密钥进行加密。程序按照加密标准的规范，进行加密。-Function as follows: to achieve the joint text file encryption, using DES encryption for text documents, using RSA key for DES encryption. Encryption Standard procedures in accorda