Full Paper: Assessing and Improving Privacy in VANETs

Vehicular ad hoc networks (VANETs) and many vehicular applications rely on periodic broadcast of location information of cars. At the same time, this information can be used to track the users whereabouts. Protecting the privacy of the users using VANETs is important, because lack of privacy may hinder the broad acceptance of this technology. We carry out an extensive risk analysis for VANETs, where we identify attacks threatening the privacy of users based on a simple cost estimation. We explicitly include existing technologies such as cellular phones in the analysis and argue that using VANET technology makes attacks on privacy less expensive. Further we identify – and rectify, where those measures have already been proposed – countermeasures against the most common attacks. As changing pseudonyms addresses many of the privacy problems that are discussed in this paper, their effectiveness is discussed as well. Finally, we propose and discuss a novel approach to changing pseudonyms, called mix contexts to improve the privacy of users in VANETs. We conclude by outlining future research directions in the field.