Performance evaluation of a distributed OCSP protocol over MANETs

Several methods that rely on public or private cryptographic systems have been proposed for trust establishment in mobile ad hoc networks (MANETs). Such methods aim to provide end-entity authentication, communications integrity and privacy. When public key certificates schemes are deployed in MANETs, they must be accompanied by efficient mechanisms for certificate revocation and validation. In this paper we address this issue, and a distributed, on-demand, OCSP-based scheme is adapted to be applicable over MANETs. This scheme, called ADOPT, uses caches of OCSP responses that are distributed and stored on intermediate nodes. ADOPT takes into account the status of intermediate nodes, such as network topology, energy thresholds, and connectivity, to materialize the caching of OCSP responses. This paper uses different MANET con-figurations to evaluate the efficiency of ADOPT. The simulation results show that ADOPT manages to rapidly identify and locate the status of a certificate without introducing significant communication or storage costs. Keywords-OCSP; MANETs; certificate status information; caching