Gaining Flexibility by Security Protocol Transfer

Even though PDAs in general - but smartcards in particular - are preferred over general-purpose computers to keep secrets, because they have meager resources, including them in security protocols is difficult. The PDAs - and again smartcards in particular - end up as a mere key-store and their processing power is not used. We describe a mechanism that allows such anemic computers to fully participate in protocols, even if the protocol in question by far exceeds their capabilities. This is done by means of machinery for transferring, at runtime, the protocol proper to a more powerful machine. We describe the mechanisms that make this possible (mainly a domain specific programming language named Obol and its implementation) and we discuss the credentials and certificates needed for the solution to maintain correctness.