A Security-Enhanced Pairing-Free Certificateless Aggregate Signcryption Scheme for Decentralized Vehicular Sensor Networks

Vehicular Sensor Networks (VSNs) are integral to intelligent transportation systems, enabling real-time communication and collaborative sensing among vehicles. However, their open wireless communication environment presents significant challenges in terms of data security and privacy protection. Although various certificateless aggregate signcryption (CLASC) schemes have been proposed to address these issues, many still suffer from security vulnerabilities and performance inefficiencies. We conduct a detailed security analysis of a recently proposed CLASC scheme by Dai et al., highlighting its susceptibility to public key replacement attacks. To demonstrate this vulnerability, we construct a specific attack algorithm and, based on our findings, propose a security-enhanced CLASC scheme. The proposed solution integrates blockchain technology to improve system decentralization, enhances resistance to collusion attacks, and supports malicious identity revocation mechanism. We provide formal security proofs under standard cryptographic hardness assumptions and evaluate the performance of the scheme through both theoretical analysis and experimental validation. The results show that our approach significantly strengthens security while maintaining high efficiency, making it well-suited for secure and scalable communication in vehicular sensor network (VSN) environments.