SSH is an acronym for Secure Shell and is the common name of a suite of programs designed by Tatu Ylönen [Tat97]. The main program, ssh, is designed to be a direct replacement for the rsh ( Remote Shell) program found on many Unix systems. SSH provides strong authentication and eliminates many known vulnerabilities. For instance, passwords are never sent over the network in clear text using SSH. In fact, using SSH, all network communications are automatically and transparently encrypted. Replacements for other utilities in the `` r*''-family of commands, such as rlogin, rsh, rcp, and rdist are also provided with ssh.
Work is underway within a working group of the IETF ( Internet Engineering Task Force) to standardize the SSH protocol.