Secure and Efficient Attribute-Based Batch Authentication Scheme for VANETs

Cloud server plays an important role in VANETs. Both vehicles and RSUs need to get data and services from the cloud server in VANETs. How to ensure the security and efficiency in the communication with cloud server is a very necessary requirement. The cloud server wishes to ensure the legality of the requirements from vehicles and RSUs before providing its services. At the same time, vehicles etc wish the cloud server to response their requirements as quickly as soon. Especially when a large number of vehicles and RSUs need the services of the cloud server, how to reduce the response time of the cloud server is an interesting topic for VANETs. This paper proposes an efficient attribute-based batch authentication scheme over lattice for VANETs. The fine-grained access control of the cloud server is achieved by designing an attribute-based signature scheme over lattice in this paper. Moreover, the cloud server can batch authenticate multiple messages from different vehicles and RSUs, which is important to reduce the response time of the cloud server in VANETs. We prove that the proposed scheme is strong unforgeable under the adaptive selective attributes and adaptive chosen message attacks in random oracle model, under the hardness of the ring shortest integer solution problem. The comparisons with several known schemes show that the proposed scheme shares some advantages with respect to the space and computation efficiency, such as the signature length and the signing/verifying time which are checked by using the Java program on a personal computer with Intel (R) Core (TM) i9-14900HX processor (2.20GHz) and 32GB RAM. A network simulation by using NS3 is also given to verify the advantages of communication effects, such as the response latency and average message loss ratios. The results show that the proposed batch authentication scheme can save about 94.81% response time of the cloud server in VANETs. Furthermore, the average message loss rate is also controlled within an acceptable interval (much less than 4.15%) even in very tense communication scenario for 1000 vehicles and fast movement speeds (25 m/s). At last, since the post quantum security of the lattice-based cryptographic, the proposed scheme is still secure even under the quantum attacks.