Highly Anonymous Mobility-Tolerant Location-Based Onion Routing for VANETs

Vehicular ad hoc networks (VANETs) have received considerable attention in recent years. Like any other network, privacy and anonymity are a requirement in VANETs. Classic anonymous routing protocols such as onion routing algorithm are fragile in mobile networks due to frequent link breaks. In this article, we propose a novel onion-based anonymous routing protocol for highly mobile vehicular networks. It introduces the concept of location-based dynamic relay groups. In this concept, vehicles dynamically form groups around specific locations to act as cryptographic onion relays. The proposed protocol satisfies source anonymity, destination anonymity, and route anonymity features and is very scalable. Employment of pseudo-IDs further helps in keeping the real identity of vehicles anonymous. The proposed protocol can modify the chain structure on the fly and make it longer to maintain source/destination location anonymity or cut it short to maintain performance. The extensive simulations conducted based on the SUMO traffic simulator showed that the proposed protocol significantly outperforms the naïve onion routing protocol in terms of delivery ratio, delay and number of retransmissions.