"All you'd have to do is build a plugin and you could completely pwn the software."

I'm building an application using plugins. I think all you have to do is build a plugin and copy it into the correct directory and my main program would happily run it. I'd like the main program to be smart enough to detect unauthorized plugins and reject them. An encrypted signature on each plugin would work well. Has anyone done anything toward a secured, and cross platform, framework for Qt plugins? Or a cross platform library for generating signatures for shared libraries?

I'm aware of how windows does this. Linux not so much. I don't need Mac compatibility.

Thanks for your time!