LaRRS: Lattice-Based Revocable Ring Signature and Its Application for VANETs.

Vehicular ad-hoc networks (VANETs) have drawn a lot of attention for their potential to improve traffic efficiency and safety. To deal with anonymous authentication and message integrity during communication, many protocols have been designed. One important approach is using Ring Signature to obtain superior security and better efficiency. However, most of the previous Ring Signature-Based authentication protocols could not support the Trusted Authority (TA) to revoke the vehicle user's identity whenever it wanted. In this article, we solve this problem and realize Conditional Privacy-Preservation Authentication successfully. As part of our work, we propose the first Lattice-based Revocable Ring Signature scheme, and prove its security under the random oracle model, which could be of independent interest. It is quantum-resistant, highly efficient, and suitable for scenarios where the TA needs to be accountable. Lastly, it is worth mentioning that we adopted a similar structure with the NIST signature standard CRYSTALS-Dilithium, which will increase the richness of the algorithm and standardization.