An Evaluation of Pseudonym Changes for Vehicular Networks in Large-Scale, Realistic Traffic Scenarios

Changing pseudonym certificates are the agreed-upon approach for privacy-friendly message authentication in upcoming vehicular ad hoc networks and are included in recent standards. This paper examines the performance of four different pseudonym change strategies and their parameters using simulations of realistic, large-scale traffic scenarios. The strategies are assessed by measuring their effectiveness and efficiency in protecting drivers from being tracked by an attacker with limited coverage. In an urban scenario, all strategies achieve satisfactory privacy protection, but the change frequency required is rather high. In a highway scenario, the attacker algorithm achieves a high-tracking success for all strategies, especially in low traffic, even for very short change intervals. This paper proposes concrete change intervals for urban scenarios, which are higher than currently foreseen, but concludes that privacy protection in uniform traffic conditions remains a challenge.