L-TCM: A Lightweight Privacy-Preserving Traffic Condition Monitoring Scheme With Source Authentication in Cloud-Assisted VANETs

In vehicular ad hoc networks (VANETs), the vehicle constantly collects traffic condition messages and uploads them to the traffic management department (TMD) for traffic analysis. Traffic condition messages usually consist of vehicle-related information as well as safety-related messages. Vehicle-related information usually contains vehicles' privacy, which cannot be broadcasted. At the same time, the safety-related message does not contain the privacy of vehicles and can be broadcasted in VANETs to ease traffic congestion. However, transmitting two types of messages separately consumes numerous computation and communication costs, which is not realistic for resource-limited vehicles. In this article, we propose a lightweight privacy-preserving traffic condition monitoring (L-TCM) scheme, where the sanitizable signature is used to enable the vehicle to broadcast safety-related messages and upload traffic condition messages by sending one message. In addition, searchable encryption is used to help the TMD retrieve traffic condition messages stored in the cloud server. Security analysis demonstrates that L-TCM satisfies security goals in VANETs. Besides, the performance of L-TCM concerning computation and communication costs makes it appropriate for traffic condition monitoring.