A secure and privacy-preserving event reporting scheme for vehicular Ad Hoc networks

In Vehicular Ad Hoc Networks (VANETs), vehicles should report events to warn the drivers of unexpected hazards on the roads. While these reports can contribute to safer driving, VANETs suffer from various security threats; a major one is Sybil attacks. In these attacks, an individual attacker can pretend as several vehicles that report a false event. In this paper, we propose a secure event-reporting scheme that is resilient to Sybil attacks and preserves the privacy of drivers. Instead of using asymmetric key cryptography, we use symmetric key cryptography to decrease the computation overhead. We propose an efficient pseudonym generation technique. The vehicles receive a small number of long-term secrets to compute pseudonyms/keys to be used in reporting the events without leaking private information about the drivers. In addition, we propose a scheme to identify the vehicles that use their pool of pseudonyms to launch Sybil attacks without leaking private information to road side units (RSUs). We also study a strong adversary model assuming that attackers can share their pool of pseudonyms to launch colluding Sybil attacks. Our security analysis and simulation results demonstrate that our scheme can detect Sybil attackers effectively with low communication and computation overhead. Copyright c © 2015 John Wiley & Sons, Ltd.