From emacs-devel:

Hello there.

I'm writing you to submit a patch for rcirc.el to give it support for
SSL connections. 

For example, the following 2 servers will connect with SSL, one using a
custom function (which can be anything, and re-implements this idea
https://github.com/nealey/rcirc/wiki ), one simply adding :use-tls t.

(setq rcirc-server-alist '(("irc.freenode.net" 
			    :nick "nick"
			    :user-name "username"
			    :port 6697
                            ;; use open-tls-stream as function to connect
			    :custom-connect-function open-tls-stream 
			    :channels ("#rcirc" "#emacs"))
			   ("irc.otherserver.org" 
			    :nick "nick"
			    :username "username"
                            ;; just say use-tls, more intuitive
                            ;; also prompted when C-u M-x rcirc
			    :use-tls t
			    :port 7000
			    :channels ("#channel1" "#channel 2"))))


The last 2 chunks of the patch are meant to strip the IRC colors. Not
really part of the "connection" patch, but IMHO useful.

The patch is meant to be applied to the latest revision published on
github by rcy:

https://github.com/rcy/rcirc

In case you're interested, I signed the emacs papers some years ago.

Bests

        Marco