Summary

Vehicular ad hoc networks (VANETs) allow vehicles to disseminate messages about road conditions to other vehicles. As long as these messages are trustworthy, they can greatly increase traffic safety and efficiency. Hence, care must be exerted to ensure that vehicle-generated messages do not convey inaccurate or false content. A natural way to proceed is to request endorsement by nearby vehicles on the content of a message originated by a certain vehicle. However, such a message generation and peer-to-peer endorsement should not result in any privacy loss on the part of vehicles co-operating in it. We survey the available solutions to this security-privacy tension and discuss their limitations. We sketch a new privacy-preserving system which guarantees message authentication through both a priori and a posteriori countermeasures.