SSHprotokolla

SSHprotokolla, or Secure Shell protocol, is a cryptographic network protocol for operating network services securely over an unsecured network. It is commonly used for remote login and command-line execution. SSH provides a secure channel over which a client can send and receive data to and from a remote server. The primary security features include strong encryption, authentication, and data integrity.

The protocol operates on the application layer and typically runs over TCP port 22. SSH consists of three main parts: the transport layer protocol, the user authentication protocol, and the connection protocol. The transport layer handles encryption and integrity checks for the data stream. The user authentication protocol handles verifying the identity of the user attempting to connect, commonly using passwords or public-key cryptography. The connection protocol multiplexes several logical channels over the secure SSH link, allowing for features like port forwarding.

SSH was developed as a replacement for Telnet and rlogin, which transmit data, including passwords, in clear text and are therefore highly insecure. SSH's widespread adoption has made it a fundamental tool for system administrators and developers for managing remote systems. Its flexibility extends to secure file transfers via SFTP (SSH File Transfer Protocol) and SCP (Secure Copy Protocol), as well as tunneling other network protocols.