The HTTP protocol:
HTTP is a hypertext transfer protocol, which is an application layer protocol based on TCP. It has three versions:
1 HTTP 1.0 can only handle one request at a time. 2 HTTP 1.1 can handle multiple requests at a time (long connection). New header fields such as Etag, if-none-match, and range are added Multiple requests can be processed concurrently (multiplexing), header data compression, server push, and data transfer in binary format
TCP protocol
TCP is a transmission control protocol characterized by a three-way handshake and a four-way wave
The three-way handshake prevents the invalid connection request segment from being sent to the server
1 The client requests a connection. 2 After receiving the request, the server confirms the online information and notifies the client. 3 After receiving the response and verifying the connection, the client notifies the server to confirm the connection.
Four waves disconnect the connection process
1 The client requests for disconnection. 2 The server notifies the client of disconnection if no task is assigned. 3 The client disconnects from the server after receiving the message.
UDP protocol.
UDP user datagram protocol (UDP) is a connectionless transport layer protocol with unreliable connections. It is a packet porter with few protocol control items, simple packets, small size, high speed, and high real-time performance. UDP is used in teleconference and multimedia data scenarios.
The HTTPS protocol
HTTP packets are transmitted in plain text. You can capture packets to view the packet content, which is easy to be hijacked and tampered with. Therefore, HTTPS, HTTPS = HTTP + TLS(Secure Transport Protocol) HTTP uses port 80. 2 HTTPS requires a certificate. 3 HTTP is a hypertext transfer protocol, which is used for plaintext transmission
The TLS protocol
The TLS protocol: Safe transport protocol for between two applications to provide confidentiality and data integrity, using asymmetric encryption algorithm to do the authentication in communication, exchange of symmetric key as talks after the key, therefore the HTTPS is divided into two stages 1 through asymmetric encryption to confirm each other legal identity, if legal session key generated 2 message before sending, First use the session key to encrypt the conversation before transmission
TLS handshake four 1 client requests to establish the SSL connection, the server receives the request and sends A random number to the client A and 2 client certificate issued by the CA authorities, after the certificate verification by generating A random number B using public key encryption, A signature is generated by B at the same time, sent to the server after 3 server receives with the private key to decrypt, The decrypted key is compared with the signature sent by the client. After the authentication succeeds, A random number C is generated and encrypted with A private key. At the same time, A hash value is generated using C and sent to the client. Subsequent packets are transmitted through symmetric session key encryption
