Privacy Protection in Vehicular Ad-Hoc Networks

The first main contribution of this chapter is to take a non-trivial step towards providing a robust and scalable solution to privacy protection in vehicular networks. To promote scalability and robustness the authors employ two strategies. First, they view vehicular networks as consisting of non-overlapping subnetworks, each local to a geographic area referred to as a cell. Each cell has a server that maintains a list of pseudonyms that are valid for use in the cell. Each pseudonym has two components: the cell’s ID and a random number as host ID. Instead of issuing pseudonyms to vehicles proactively (as virtually all existing schemes do) the authors issue pseudonyms only to those vehicles that request them. This strategy is suggested by the fact that, in a typical scenario, only a fraction of the vehicles in an area will engage in communication with other vehicles and/or with the infrastructure and, therefore, do not need pseudonyms. The second main contribution is to model analytically the time-varying request for pseudonyms in a given cell. This is important for capacity planning purposes since it allows system managers to predict, by taking into account the time-varying attributes of the traffic, the probability that a given number of pseudonyms will be required at a certain time as well as the expected number of pseudonyms in use in a cell at a certain time. Empirical results obtained by detailed simulation confirm the accuracy of the authors’ analytical predictions.