NTRU-CLSC: Efficient Quantum-Resistant NTRU Lattice-Based Certificateless Signcryption Scheme for VANETs

With the development of the Internet of Things (IoT), ensuring secure, real-time communication and privacy in Vehicular Ad Hoc Networks (VANETs) has become a critical challenge. Certificateless signcryption offers a promising solution by eliminating certificate management issues, however, existing schemes struggle to balance post-quantum security with computational efficiency. Most rely on computationally expensive bilinear pairings or general lattices and often lack robust defenses against public key replacement attacks. To address these issues, we propose NTRU-CLSC, an efficient NTRU Lattice-based certificateless signcryption scheme. We leverage efficient polynomial-ring operations to reduce computational cost. We further adopt the Antrag trapdoor mechanism to bind user public keys to the KGC-generated primary trapdoor, thereby preventing public key replacement attacks. In addition, the scheme supports batch verification to reduce latency in high-concurrency scenarios. Security proofs and performance evaluations demonstrate that the proposed scheme can satisfy the security and privacy requirements of VANETs, while achieving better efficiency compared with existing quantum-resistant signcryption schemes.