stunnel

The stunnel program is designed to work as an SSL encryption wrapper
between a remote client and the local (inetd-startable) or remote
server. The concept is that by having non-SSL aware daemons running on
your system, you can easily set them to communicate with clients over a
secure SSL channel. Stunnel can be used to add SSL functionality to
commonly used inetd daemons, such as POP-2, POP-3, and IMAP servers,
without any changes to the program code.