[Haskell-cafe] Tips for deployment?

Hi all, my haskell app is getting closer to shipping and what I need to do now is to give product protection some thought. The product is for hospitals and therefore a very limited set of clients. I do not expect anyone to try to "hack" my application but I need a basic protection mechanism in place, if only to check for a valid license key. As I've never done this before I'd be grateful for some suggestions here. Günther