Serviio

The console is running on http://host:23423/console/
How to make the server secure, running on https with credentials? Also for rest API, of course.

(It would be good for any system, my is running on Linux, so I prefer a solution for it.)

It is accessible via HTTPS (use 23523 as the port number) but there is no way to require credentials to access it. It shouldn't be an issue within your home network (unless kids or friends like to mess with you), and I would never make the console visible through your network firewall on the public Internet.