stunnel is a universal wrapper that adds SSL (read `encryption', and
therefore greater security) to any network service. It can
be installed site-wide, or used on an ad-hoc basis by an individual
user for an individual service for port forwarding (like SSH).
It lives at
http://www.stunnel.org/. At CCIS, we use it for the web server that serves mailing
lists at
http://lists.ccs.neu.edu/, so people's mailing list passwords aren't transmitted in the
clear.
There's a handy cheat-sheet for using
stunnel along with
thttpd (or any other non-SSL-capable HTTP server) at
http://halplant.com:88/server/thttpd_FAQ.txt, about two-thirds of the way down. You can also use it (with
some trouble) to access SSL-secured pages with a non-SSL web browser;
I've used this on my iPAQ to access CCIS'
Nomad login page, for instance.