Secure Shell, commonly known as SSH, is a cryptographic network protocol that enables secure communication between devices over an unsecured network. It is widely used for remote login and command execution, providing a secure channel over an otherwise insecure connection, such as the internet. By encrypting the data transmitted between the client and server, SSH ensures that sensitive information remains confidential and protected from eavesdropping. It is an essential tool for system administrators and developers, allowing them to manage servers and transfer files securely, thereby enhancing overall network security.