Definition
SSH, or Secure Shell, is a network protocol used for secure remote login and other secure network services over an unsecured network. It achieves security by encrypting the entire session, ensuring that data transmitted between two networked computers remains confidential and unaltered. SSH typically operates by establishing an encrypted tunnel between a client and a server, allowing for secure command execution, file transfers, and tunneling of other network protocols. This protocol is crucial for system administrators and developers who need to manage servers and transfer sensitive data remotely without risking exposure. For instance, an administrator might use SSH to securely connect to a cloud server to deploy an application update. Unlike Telnet, which transmits data in plain text, SSH provides robust encryption to protect against eavesdropping and man-in-the-middle attacks. You will encounter SSH concepts on exams like CompTIA Security+, CySA+, and CISSP, as well as in cloud architecture domains.