Optimal revocations in ephemeral networks: A game-theoretic framework

Revocation of public-key certificates is an important security primitive. In this paper, we design a fully distributed local certificate revocation scheme for ephemeral networks - a class of extremely volatile wireless networks with short-duration and short-range communications - based on a game-theoretic approach. First, by providing incentives, we can guarantee the successful revocation of the malicious nodes even if they collude. Second, thanks to the records of past behavior, we dynamically adapt the parameters to nodes' reputations and establish the optimal Nash equilibrium (NE) on-the-fly, minimizing the social cost of the revocation. Third, based on the analytical results, we define a unique optimal NE selection protocol and evaluate its performance through simulations. We show that our scheme is effective in quickly and efficiently removing malicious devices from the network.