1) handshake protocol: This protocol is responsible for the encryption parameters used for the session between the client and the server. When SSL client and server start to communicate, they agree on the protocol version, choose encryption algorithm and verification method, and use public key technology to generate * * * shared key.

2) Recording protocol: this protocol is used to exchange application data. Application messages are divided into manageable data blocks, which can also be compressed to generate MAC (Message Authentication Code), and then the results are encrypted and transmitted. The receiver accepts and decrypts the data, checks the MAC, decompresses and reassembles the data, and provides the results to the application protocol.

3) Warning protocol: This protocol is used to indicate when an error occurs or when the session between two hosts is terminated. The handshake steps of SSL protocol communication are as follows: