说明：  公钥密码！主要是实现文件的加密和解密功能，突破传统对称的密码体制的缺点，对网络密钥的分配起到了很好的作用
(Public-Key Cryptography! Mainly the realization of the document encryption and decryption functions, has broken through the traditional symmetric cryptosystem shortcomings, the distribution of keys on the network has played a good role)