BAC-CRL: Blockchain-Assisted Coded Caching Certificate Revocation List for Authentication in VANETs

Vehicular Ad Hoc Networks (VANETs) are considered the technological upheaval for improving road safety and traffic efficiency by enabling the wireless and network communications among vehicles and infrastructures. Certificate Revocation List (CRL)-based schemes are the most widely used recovery mechanism for VANETs to eliminate the negative effect of security and privacy attacks. However, providing an efficient and low-cost CRL-based scheme for certificate revocation is still a challenging issue since the communication resources must be capable of carrying various applications apart from the security and privacy purposes. Thus, in this paper, a Blockchain-Assisted Coded Caching Certificate Revocation List, called BAC-CRL, is proposed for authentication in VANETs. In BAC-CRL, the blockchain technology is leveraged to unite regional Trust Authorities (TAs) and Road-Side Units (RSUs) into a blockchain network, which uniformly manages and stores multipart CRLs for preventing resource-constrained On-Board Units (OBUs) to be overwhelmed. In addition, a multi-layer coded caching strategy is further designed in BAC-CRL to distribute the minimum bits of CRLs that satisfies the revocation requirements, aiming to reduce the communication overhead and shorten the processing time cost. Moreover, a novel anonymous authentication mechanism is developed utilizing the proposed BACCRL to achieve conditional privacy preservation with efficient certificate revocation. Security analysis and extensive simulations demonstrate that the proposed BAC-CRL is secure and computationally efficient for vehicle revocation.