VANET Privacy Protection Protocol Based on Claimable Ring Signature

The Vehicular Ad-hoc Network (VANET), as a core component of intelligent transportation systems, connects participants such as vehicles and roadside units (RSUs) through information and communication technologies to enhance traffic safety and optimize road usage efficiency. However, as VANET applications expand, the security of information exchange and the protection of user privacy have emerged as critical challenges. If private data such as vehicle locations and driving routes are leaked, users may face significant risks. Ring signature schemes have been applied in VANETs to provide information authentication while preserving user privacy. However, in scenarios requiring accountability, the anonymity of traditional ring signature schemes hinders the ability to trace vehicle responsibility. To address this issue, this study introduces a claimable ring signature scheme, which allows the signer to reveal their identity to meet legal accountability requirements. By designing a DualRing structure, the scheme reduces signature size using inner-product parameters and constructs a dynamic anonymous ring, enhancing the flexibility and efficiency of privacy protection. Experimental results show that, while maintaining computational costs comparable to those of DualRing, the communication overhead of the claimable ring signature scheme is significantly lower than that of existing ring signature schemes.