Reliable, secure and privacy-preserving collaborative downloading scheme in VANETs

Collaborative downloading, as a promising application in Vehicular Ad-hoc Networks (VANETs), can effectively address the demand of vehicles for high-quality resources in VANETs. However, there are still security and privacy issues in collaborative downloading. Therefore, in this paper, we propose a reliable, secure and privacy-preserving collaborative downloading scheme which effectively achieves message authentication and privacy protection. Besides, in the proposed scheme, we also use a homomorphic network coded signature to ensure sequential verification of file blocks and design a new vehicle selection algorithm, a reward and contract mechanism to improve the reliability of collaborative downloading. Experiments show that our scheme is reliable and practical.