main函数文件输入明文，调用秘钥留生成函数（get_k文件）以及加解密函数（encrypt_fcn文件），完成对明文的加密和解密(Encryption and decryption of plaintext are accomplished by inputting main function file into plaintext, calling secret key generation function (get_k file) and encryption and decryption function (encrypt_fcn file).)