Which protocol is commonly used for secure remote shell access?

The protocol commonly used for secure remote shell access is SSH, which stands for Secure Shell. SSH is designed to provide a secure channel over an unsecured network by using encryption. This allows users to access a remote computer over a network securely, ensuring that the data being transmitted is protected from eavesdropping, tampering, and other potential attacks.

SSH supports various authentication methods, including password-based and key-based authentication, making it versatile and secure for different use cases. By using SSH, both the commands sent to the remote server and the responses received are encrypted, providing confidentiality and integrity.

In contrast, protocols like Telnet and FTP do not have built-in security features and transmit data, including passwords, in plain text, which can be intercepted by malicious actors. HTTP, while capable of secure communication through HTTPS, is not specifically designed for remote shell access and does not provide the functionalities necessary for this purpose. Therefore, SSH is the preferred choice for securely accessing remote systems through a shell interface.