I'm not kidding. I wanted to try Krita on my Windows 10. I got a blue dialog claiming that the installer was stopped since it came from an unknown developer.



I don't know how this is done, but it needs to be done none the less.

if you click on "more info" in the dialog window you posted you can choose to install the software.

I'm not a developer but I believe it is not as simple as just making the software "recognized" under windows.

Yes, certificates cost money, and the question is: is it worth the money? Especially if it doesn't matter for how well krita runs. Just don't download krita from kickass.to...