To allow a Remote Desktop connection, in the client side can be use Remmina and in the server is mandatory enable the Remote Desktop option, it through Settings → Sharing. This GUI is the same for Ubuntu and Fedora.
In the bottom of the Remote Desktop window exists the Authentication section and the Verify Encryption button. If it is press it appears a small window with the Encryption Fingerprint value - it in the server side. For the client side - this value appears for the first attempt connection as a Certificate. Is mandatory accept that Certificate to accomplish the first connection and make others in the future.
Just being curious, for security reasons, is there a way to regenerate or create a new fingerprint?
Consider the case if exists 3 remote clients (does not matter if is the same person or not) and the laptop/PC of one of them was either compromised or stolen. Yes, I know that can be changed the User Name and Password, but to increase the security is possible change or recreate/generare a new Fingerprint?