Efficient VANET safety message delivery and authenticity with privacy preservation.

Vehicular ad-hoc networks (VANETs) play an essential role in the development of the intelligent transportation system (ITS). VANET supports many types of applications that have strict time constraints. The communication and computational overheads are minimal for these computations and there are many security requirements that should be maintained. We propose an efficient message authentication system with a privacy preservation protocol. This protocol reduces the overall communication and computational overheads. The proposed protocol consists of three main phases: the group registration phase, send/receive messages phase, and the leave/join phase. For cryptography algorithms, we combined symmetric and asymmetric key algorithms. The symmetric key was generated and exchanged without using the Diffie-Hellman (DH) protocol. Furthermore, we used an efficient version of the RSA algorithm called CRT-RSA. The experimental results showed that the computational overhead in the registration phase was significantly reduced by 91.7%. The computational overhead for sending and receiving the non-safety message phase was reduced by 41.2% compared to other existed protocols. Moreover, our results showed that the time required to broadcast a safety and non-safety group message was below 100 ms and 150 ms, respectively. The average computational time of sending and receiving a one-to-one message was also calculated. The proposed protocol was also evaluated with respect to performance and security and was shown to be invulnerable to many security attacks.