A Decentralized Group Privacy Protocol for Vehicular Networks

Vehicular Networks by means of Car-to-X (C2X) communication aims to enhance road safety and traffic efficiency by exchanging foresighted traffic information. For successfully establishing this technology on the market, C2X messages have to be secured and the driver's privacy must not be violated. However, currently applied pseudonymization strategies provide only basic protection against profiling and are entirely ineffective towards a powerful global adversary. We present a novel group privacy protocol, which creates dynamic cryptographic 'Mix Zones' in a decentralized and cooperative way. The proposed protocol obfuscates pseudonym changes and thus reduces trace ability of vehicles significantly. While geographical cells are used to establish a secret group key among all members, the group is maintained even when travelling along the road. Using the group key, a vehicle is able to send secure authenticated messages, though its anonymity is preserved. We simulate the proposed protocol by means of a dedicated C2X simulator and evaluate the achieved privacy enhancements with respect to a global passive adversary.