Anonymous-authentication scheme based on fog computing for VANET.

Privacy protection in vehicular ad hoc networks (VANETs) has always been a research hotspot, especially the issue of vehicle authentication, which is critical to ensure the safe communication of vehicles. However, using the real identity in the process of authentication can easily result in a leak of the privacy information of the vehicles. Therefore, most existing privacy-protection schemes use anonymous authentication and require one-to-one communication between vehicles and the trusted authority (TA). However, when the number of vehicles is too large, network congestion can take place. In addition, the process of updating the anonymous by the TA or the vehicle itself, can result in both poor real-time performance and leakage of the system master key. To solve these problems, this study proposes a fog-computing-based anonymous-authentication scheme for VANETs; the scheme reduces the communication burden of the TA by enabling self-authentication between vehicles and road-side units (RSUs), thus improving the vehicle-authentication efficiency. For updating the anonymous, we design a fog-computing-based pseudonym-updating and -tracking strategy, which guarantees real-time communication and reduces the instances of re-authentication interactions for legitimate vehicles. The experimental results show that the scheme not only meets the privacy-protection requirements of VANETs but also offers better performance than that of the existing anonymous-authentication schemes.