Decentralized handover authentication for internet of vehicles based on dual blockchains

In the Internet of Vehicles (IoV), vehicles communicate with roadside units (RSUs) over open wireless channels, and frequent handovers create a critical security surface. We propose a decentralized handover authentication scheme based on a dual-blockchain architecture that separates authentication state according to its scope and lifetime. A global blockchain maintains long-term identities and public keys, whereas local blockchains shared among geographically adjacent RSUs store short-lived handover tokens. This separation enables intra- and inter-group handover authentication without pre-shared inter-RSU keys or a secure inter-RSU channel, while avoiding global replication of temporary credentials. We analyse security informally against conventional and blockchain-specific threats under the practical Byzantine fault tolerance (PBFT) fault bound, prove session-key security in the real-or-random model, and verify the protocol using AVISPA. Performance is evaluated through computation and communication costs compared with blockchain-assisted handover schemes and recent authentication frameworks, PBFT latency simulations, and SUMO-based mobility simulations across 135 scenarios. The results show that intra-handover requires 9.721 ms and 1664 bits, that newly issued tokens can be confirmed before the next handover in all evaluable cases even under a 2.138-s consensus delay, and that per-RSU token storage decreases in proportion to the number of local blockchain groups.