SSH (Secure Shell) is a cryptographic network protocol that is used for secure data exchange, remote command line login, and remote command execution. The SSH protocol operates on a client-server model. It provides an encrypted channel between them and prevents unauthorized access to data.
SSH Mechanisms
The effectiveness of SSH lies in its reliability and versatility, which can be attributed to its key mechanisms: encryption, authentication and integrity.
Encryption. SSH uses three types of encryption. Symmetric encryption protects the actual data during transmission, while asymmetric encryption and hashing protect the initial connection setup.
Authentication. SSH uses public key authentication to verify the identity of the client on the server and vice versa. This prevents unauthorized users from gaining access.
Integrity. SSH uses cryptographic hashes to provide an additional layer of security. This approach ensures that the data has not been tampered with during transmission.
Using the SSH protocol
SSH’s robust security mechanisms make it an indispensable tool for many applications.
Secure file transfer. The SFTP and SCP protocols use SSH to ensure secure file transfer over the network.
Remote system administration. System administrators use SSH to remotely manage systems and applications.
Tunneling and port forwarding. SSH can create secure tunnels between networks, allowing insecure protocols to be encrypted.