1) Encryption mechanism: data encryption is

And form ciphertext that is difficult to understand. According to the similarities and differences between the encryption key and the decryption key, there are two kinds of symmetric cryptosystems (encryption and decryption use the same key) and asymmetric cryptosystems. 2) PKI and digital signature PKI is the foundation of Ca security certification system, which can realize the management of Ca and certificate: key backup and recovery