One of the coolest things about UNIX has been that there is not one but several different ways to administer systems from remote consoles. Sad to say, most of these methods (Telnet, rsh and X, to name a few) send everything . . .
One of the coolest things about UNIX has been that there is not one but several different ways to administer systems from remote consoles. Sad to say, most of these methods (Telnet, rsh and X, to name a few) send everything over the network in clear text, including passwords. The combination of our reliance on the Internet with the proliferation of script kiddies and other packet-sniffing deviants has made administrative clear-text network applications obsolete.

But a few years ago Finnish über-hacker Tatu Ylonen created a mind-blowingly cool thing called the Secure Shell, or ssh. ssh is a suite of tools that roughly correspond to Sun's rsh, rcp and rlogin commands, but with one very important difference: paranoia. ssh lets you do everything rsh, rcp and rlogin do, using your choice of libertarian-grade encryption and authentication methods. But wait--there's a catch--ssh version 1 relies heavily on RSA, an excellent, but as we say, encumbered (patented) technology that requires any application that uses it to be licensed (paid for) unless it's used in noncommercial settings (even in noncommercial use ssh's legality has always been murky, especially in the US). But wait, you say, RSA's US patents expired in September 2000--problem solved, right? Almost: Tatu's got to earn a living, so by the time RSA became less encumbered, ssh itself had become more so as his company F-Secure tightened the licensing reins. In fact, beginning with ssh version 2.0, unlicensed/free commercial use (regardless of RSA issues) was no longer permitted. All this despite Tatu's sincere desire that ssh become an Internet standard, one of the requirements of which is that at least one free implementation be available.

The link for this article located at Linux Journal is no longer available.