Blockchain-assisted certificateless signcryption for vehicle-to-vehicle communication in VANETs

In vehicular ad-hoc networks (VANETs), real-time messages are used to guarantee transportation efficiency and passenger safety through the exchange among vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I). Therefore, the timely acceptance of safety messages is critical to establishing efficient and reliable communication in VANETs, which hinges on an efficient privacy-preserving authentication mechanism. However, these mechanisms face either security or performance problems. Although some state-of-the-art signcryption schemes meet the needs of security requirements of authentication, performance is not efficient in computational overhead for an increase of the bilinear pairing operations in batch unsigncryption verification. Therefore, we have designed an efficient and provably secure blockchain-assisted certificateless signcryption (BACLS) that provides a feasible security communication in theoretical analysis and experiments. The BACLS scheme ensures security against type-I and type-II attackers in regard to existential unforgeability against adaptively chosen message attacks (EUF-CMA) under the hardness assumption of the gap bilinear Diffie- Hellman problem and indistinguishability against adaptive chosen ciphertext attack (IND-CCA2) under the hardness assumption of the elliptic curve discrete logarithm problem in the random oracle model (ROM). The experiments demonstrate that the BACLS scheme significantly reduces unsigncryption computational costs and power consumption in contrast to state-of-the-art schemes, and promotes the development of a decentralized authentication system in VANETs.