If your problem doesn't fit into PGP or TLS, refactor your problem.<p>There are high-level crypto libraries (though none that I recommend without hesitation) that provide essentially the same features as PGP. If you're going to make a concession, perhaps that's the one you could consider. However:<p>* I don't recommend doing so, and<p>* It's not that much of a concession, because you still have to wrap your application around the cryptosystem, not the other way around.