BAP: A Blockchain-Assisted Privacy-Preserving Authentication Protocol With User-Controlled Data Linkability for VANETs

With the proliferation of vehicular networking and data in the era of Vehicular Ad-hoc Networks (VANETs), ensuring privacy-preserving authentication and data privacy during analysis has emerged as a pivotal research focus. In this paper, we propose a blockchain-assisted privacy-preserving authentication protocol Bap with user-controlled data unlinkability for VANETs. We leverage Pointcheval-Sanders (PS) signatures to design a privacy-preserving authentication protocol that supports user traceability and revocation of malicious users. Additionally, we introduce an auxiliary data processor (DP) in our model to analyze VANET data with explicit and implicit linkability. The DP is capable of linking messages on the same or different topics, enabling minimal privacy disclosure during Big Data analysis. We provide a detailed proof and demonstrate that our scheme satisfies the required properties. Finally, performance evaluations demonstrate the efficiency of our proposed scheme. While supporting the mentioned functionalities, the gas cost is limited to a small range, and the signature size is only 354 bytes.