RSA简洁幽雅，但计算速度比较慢，通常加密中并不是直接使用RSA 来对所有的信息进行加密， 最常见的情况是随机机产生一个对称加密的密钥，然后使用对称加密算法对信息加密，之后用 RSA对刚才的加密密钥进行加密。 已通过测试。

-RSA simple and elegant, but relatively slow computing speed, usually not directly use RSA encryption to encrypt all the information, the most common situation is randomly generated by a symmetric encryption key, then use the symmetric encryption algorithm to encrypt information after just encryption key is encrypted using RSA. Has been tested.