Conditional privacy-preserving and efficient distributed IoV data sharing scheme based on a hierarchical and zonal blockchain

With the prevalence of intelligent driving, the vehicular data corresponding to driving safety and traffic management efficiency is widely applied by the Internet of Vehicles (IoV) applications. Vehicular data is shared frequently in IoV, leading to privacy leakage of the message sender, yet most privacy-preserving measures bring difficulties for receivers to detect malicious messages. To trade-off between privacy and security, conditional privacy-preserving authentication (CPPA) solutions have been proposed. However, CPPA protocols deployed in IoV rely on hardware devices or center servers to manage key generation and updates. This paper proposed a blockchain-based CPPA mechanism for IoV data-sharing to mitigate these challenges. A hierarchical key generation mechanism is presented to protect drivers' privacy and authenticate messages which is suitable for resource-limited IoV nodes. Management nodes can issue temporary pseudo-identity (PID) from their keys for vehicles to interact in their area and trace the malicious behaviors, but know nothing about vehicles' activities outside their administration. A hierarchical and zonal blockchain is presented to realize distributed fine-grained IoV management and enhance efficiency concerning traditional blockchain. Specifically, we propose a cross-domain data-sharing mechanism, which can facilitate efficient communication and a mutual cross-domain chain verification to guarantee the security of each domain blockchain in our IoV system. The security analysis and performance evaluation demonstrate the security as well as computational and storage efficiency of our scheme.