The current version of SSH (Secure Shell) is SSH-2, which was released in 2006.
SSH is a cryptographic network protocol that allows secure communication between two networked devices. SSH works by providing a secure channel between two devices for data exchange, while also providing authentication and encryption. The encryption provided by SSH prevents attackers from eavesdropping on the communication or tampering with the data being transmitted.
The technical description of the SSH process involves several steps. First, the client initiates a connection to the server by sending a TCP SYN packet. The server then responds with a TCP SYN-ACK packet. Once the TCP handshake is complete, the client and server establish an SSH handshake.
During the SSH handshake, the client and server agree on a cipher suite to use for encryption and key exchange. The server then sends its public key to the client for authentication. The client uses the server’s public key to encrypt a random session key and sends it back to the server. The server decrypts the session key using its private key and sends an acknowledgement to the client indicating that the session key has been received.
Once the key exchange is complete, the client and server use the session key to encrypt and decrypt data during the session. The data is also hashed to ensure its integrity. The session key is discarded when the session is closed.
Overall, SSH provides a secure and reliable method for remote access and data transfer over a network, making it a popular choice for system administrators and developers.
