OpenSSH is a suite of secure networking utilities based on the Secure Shell (SSH) protocol, which provides a secure channel over an unsecured network in a client-server architecture. It is an open-source implementation of the SSH protocol, based on the free version by Tatu Ylonen and further developed by the OpenBSD team and the user community. OpenSSH is not a single computer program, but rather a suite of programs that serve as alternatives to unencrypted protocols like Telnet and FTP. The suite consists of several tools, including ssh, scp, sftp, ssh-add, ssh-keysign, ssh-keyscan, ssh-keygen, sshd, sftp-server, and ssh-agent. OpenSSH encrypts all traffic to eliminate eavesdropping, connection hijacking, and other attacks, and provides a large suite of secure tunneling capabilities, several authentication methods, and sophisticated configuration options. OpenSSH is integrated into several operating systems, including Microsoft Windows, macOS, and most Linux operating systems, while the portable version is available as a package in other systems. The OpenSSH server program is called sshd, and the server is typically started during boot.