SmartMob-PPT-CLAMA: Traceable anonymous authentication for V2X mobility

Smart mobility ecosystems connect autonomous vehicles, shared mobility platforms, electric-vehicle charging infrastructure, pedestrians, and roadside units through real-time V2X messages. This paper redesigns PPT-CLAMA, a privacy-preserving and traceable certificateless anonymous mutual authentication scheme, for high-speed internet of vehicles (IoV) and smart mobility environments. The proposed SmartMob-PPT-CLAMA introduces mobility-adaptive pseudonym pools, RSU-assisted handover caching, lightweight V2X authentication headers, hierarchical traceability, and Sybil aware regional trust filtering. The protocol preserves the original security objectives of anonymity, unlinkability, perfect forward secrecy, known session-specific temporary information security, and lawful traceability, while addressing mobility-specific weaknesses such as long-lived pseudonym tracking, handover re-authentication delay, centralized trace authority failure, high-speed Sybil attacks, and broadcast replay. In the evaluated Raspberry Pi 4B and SUMO/NS-3 workload, the proposed design reduces authentication delay from 1.10 ms to 0.82 ms, reduces communication overhead from 470 bits to 312 bits, and achieves 99.1% handover re-authentication success. The design is mapped to ETSI ITS security, IEEE 1609.2, ISO/SAE 21434, and GDPR Article 32 requirements.