Weird
Just checked -AMSO's meshes are just plain msh files with accurate data - you can load them easily. (On the other hand I checked version 1.16 and not the most recent, plus i checked only few meshes)
Anyway, there is no technical limitations for encrypting orbiter's meshes - you can decipher mesh into temporary file, oapiLoadMeshGlobal it and delete file.
Or if you think having file is insecure way, you can cipher meshes data and not the file itself.
But this will giveaway the number of groups and vertices you use so you'd better try to dynamicaly generates meshes. I have no idea about it. Try asking Artlav about Orulex - It looks like he knows the way.
Still it leaves your data vulnerable - it is in memory and not encrypted - you'd better clean or encrypt after every orbiter's render.
But that will kill framerates and will not make your data really safe - it can be attacked during render. So have to wait next orbiter's version and make your own visualisation program for it.
Also try to limit printscreening ability of user - it will make reverse engineering your mesh difficult.
But seriously, what's the point? Limiting use of your meshes just limits growth of orbiter (indirectly but it does). Still it is your property, so If you don't wan't your meshes to be reused just tell/write so - it will be enough. (or apply few transformations and shuffle vertices - that will be more than enough
EDIT: found the original thread. Looks like AMSO is indeed encrypting it's meshes. Strange move. I doubt anyone in orbiter community would steal the meshes. At least as long as AMSO is up and running.
The only thing that comes to mind: AMSO preparing to go commercial with it's own game engine. Looks like Alain Capt trying to protect meshes from salvaging after AMSO's departure from Orbitersim.
