Secure Shell (operating system) (ssh) A Unix shell program for logging into, and executing commands on, a remote computer. ssh is intended to replace rlogin and rsh, and provide secure encrypted communications between two untrusted hosts over an insecure network. X11 connections and arbitrary TCP/IP ports can also be forwarded over the secure channel.
http://cs.hut.fi/ssh/. Last updated: 1997-01-07