This paper is concerned with authenticated communication using public
keys which has been designed to minimize the potential for
denial-of-service attacks in an ad-hoc network. To this aim, we use
substantial hardware support and require certain properties from the
network. We show how communication partners get the public keys and how
keys can be changed. We consider various methods of attack and their
effect on our system. Although we can diminish the attack possibilities,
we cannot completely protect our system from denial-of-service attacks
due to its ad-hoc nature.