Secure Shell (SSH) provides a technology for encrypting communication between two computers. The Open Source OpenSSH project provides a freely available implementation for all major operating systems. Many Ruby on Rails utilities, as well as plain old shell access, make use of SSH terminal sessions. SSH also provides secure communication tunnels for other applications, and secure file transfer between hosts.
With a basic SSH setup, you have to enter your password every time you log in to the server, which is not unreasonable from a security perspective. But if just use a password, you'll end up typing that it over and over again, even for a single deployment. Fortunately, there is a mechanism to avoid this ... continue...