A resilient in-network aggregation mechanism for VANETs based on dissemination redundancy

In the field of Vehicular Ad-hoc Networks (VANETs), traffic efficiency applications, such as traffic information systems, are particularly challenging, because they often require the dissemination of information within large geographic areas. Forwarding information over multiple hops is a necessity, and due to the amount of available information, the available wireless capacity is easily exhausted. In-network aggregation protocols are often used to cope with wireless channel restrictions. Their aim is to collaboratively create summaries of traffic information and other information items as information is disseminated within the network. But in-network aggregation is challenging form a security perspective: insider attackers may be able to alter not only their own observations but also modify already aggregated information, or they may introduce false aggregates. As a result, wrong routing decisions may be taken, or drivers may engage in dangerous driving maneuvers. Existing security mechanisms for in-network aggregation often introduce considerable additional overhead, resulting from cryptographic proofs, such as signatures. In this work, we follow a different approach: we design a resilient aggregation mechanism that leverages already existing communication redundancy and combines it with data consistency checks to identify and filter false aggregates information. Our security mechanism introduces limited additional overhead, and simulation results show that at least 20% attacker vehicles can be tolerated by our mechanism. (C) 2015 Elsevier B.V. All rights reserved.