Dependable and secure geocast in vehicular networks

Inter-vehicular communication envisions many applications to enhance traffic safety. One fundamental communication paradigm used to realize a wide range of such applications is called Geocast, that is, multi-hop broadcast dissemination of messages within a geographically restricted destination region. Because of the safety-related nature of many VANET applications, it is crucial that Geocast protocols ensure dependable dissemination of information. Here, dependability has two aspects. First, a Geocast protocol needs to scale to varying node densities - reliable delivery should be provided both in sparsely connected networks and also in scenarios with high channel load due to high node density. In addition, Geocast needs to be protected against attacks to achieve dependable dissemination of information even in presence of malicious nodes trying to suppress information delivery. In this work, we focus on the goal of Geocast security. We evaluate the impact of several attacks, and, based on these results, we introduce specific countermeasures against the discovered threats. Particularly, we highlight the intrinsic security properties already present in scalability-enhancing mechanisms. Thus, we show how security and scalability complement each other in Geocast protocols. In summary, our focus are lightweight and efficient measures to secure Geocast for usage in VANETs.