Blockchain-based security for the Internet of Vehicles (IoV) research emphasizes how decentralized ledger technology can address trust, privacy, and reliability challenges in highly dynamic vehicular networks. Research papers in this area explore blockchain’s role in securing vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), and vehicle-to-everything (V2X) communications by ensuring tamper-proof data sharing, preventing spoofing, and mitigating Sybil or denial-of-service attacks. Studies highlight applications such as secure traffic data exchange, decentralized vehicular identity management, accident forensics, automated tolling, and fraud-resistant vehicular payments. Smart contracts are investigated for enabling autonomous services like ride-sharing, insurance claims, and predictive maintenance, all while ensuring transparency and accountability. Key challenges including scalability, latency, storage overhead, and privacy protection in fast-moving vehicular environments are analyzed, with proposed solutions such as lightweight consensus algorithms, sharding, off-chain storage, and integration with edge/fog computing. Overall, research in this domain demonstrates how blockchain strengthens IoV ecosystems by creating secure, reliable, and efficient infrastructures for next-generation intelligent transportation.