The rapid progress of the Internet of Vehicles (IoV) has created new potential for intelligent transportation systems (ITS), including improved connectivity between vehicles, roadside units (RSUs), and cloud servers. However, effective, safe, and scalable authentication and key management are required to maintain the security of vehicle communication. This paper introduces a certificate-less authentication and key management mechanism explicitly designed for dynamic IoV environments. The proposed framework uses secure key exchange, cluster formation for efficient intra-vehicle communication, and mutual authentication between vehicles, RSUs, and cloud servers rather than traditional certificate-based public key infrastructures (PKI). By eliminating the certificate requirement, the protocol minimizes communication overhead and computational complexity while retaining a strong security posture. Simulation results show that the protocol is effective at securing vehicle-to-vehicle (V2V), vehicle-to-RSU (V2RSU), and RSU-to-cloud server communications, with low latency, high scalability, and resilience to known security attacks such as replay, impersonation, and man-in-the-middle attacks. This study provides a unique, lightweight, and secure approach for next-generation IoV systems, supporting a safe and efficient ITS ecosystem.