SSL when running Calibre as local server

I am using Calibre as server running on my own personal computer.
Then I succeeded in putting it online using the https://my.noip.com service.
You may reach it here:
http://sinapsi.zapto.org/
and obviously it works only when Calibre is running on my pc.

I'd like to implement the SSL protocol
https://sinapsi.zapto.org/

I've seen the option in advanced server settings.
But I don't know where get these SSL certificate and SSL private key.

Any help?

Many thanks.