Marrying safety with privacy: A holistic solution for location privacy in VANETs

Existing privacy measures often conflict with the requirements of future vehicular networks. First and foremost, in attempting to achieve local privacy, they interfere with the primary purpose of vehicular networks: to improve road safety. Other solutions undermine accountability or introduce too high overhead to be of practical use. For this reason, proper privacy protection is disregarded in many field experiments, proposals, and standardization documents. In this paper, we take a structured approach to deriving a holistic solution for location privacy protection in Vehicular Ad-Hoc Networks (VANETs): Under reasonable assumptions about an adversary's capability, local privacy is neither required nor can it be achieved without compromising traffic safety. Our approach is therefore based on synchronized time-slotted pseudonym pools and the local announcing of pseudonym changes. By this, we overcome the privacy-safety problem while at the same time increasing privacy for all users. Our system is fully compatible with the requirements of vehicular networks and current standardization efforts.