Secure and efficient vehicle data downloading scheme with privacy-preserving in VANETs

Data downloading is a basic data transfer requirement in VANETs. Cooperation data downloading can use V2C, V2I and V2V communications to improve the data downloading efficiency. Security and identity privacy preserving of data downloading should be paid more attention to protect the required vehicle. Otherwise, the data and identity information leakages would lead to immeasurable loss. To address these challenges, we propose a lattice-based secure vehicle data downloading scheme with privacy-preserving for VANETs. The vehicle request message authentication and identity privacy of the vehicle are achieved by a designed lattice-based ring signature. We prove that the proposed scheme is strong unforgeable and unconditional privacy preserving in the random oracle model. The request data also is encrypted by a symmetric encryption algorithm to achieve the data confidentiality. Moreover, thanks to the post-quantum security of the lattice based cryptographic tools, the proposed data downloading also can defend against the quantum attacks. the same time, cooperation data downloading also can be used in this paper to improve the effects of data downloading. Performance comparison and analysis shows that the proposed scheme shares some advantages with respect to the space and computation efficiency. The main character of the proposed scheme is that the impact of the vehicle ring group number on both the computation and space efficiency is effective controlled, such as the fixed signature length for any ring group size. As a result, the bandwidth and computation resources of VANETs can be saved by using the proposed scheme. We also simulate the proposed scheme by NS which shows the average download success ratio is always within the interval [95% - 100%] and cooperative downloading can improve the downloading efficiency by 86%.