Enhanced modified SecOC protocol for secure automotive networks a comprehensive cryptographic framework

In this paper, we propose an Enhanced Secure Onboard Communication (SecOC) protocol with dynamic freshness values and multi-layered authentication, addressing advanced cybersecurity threats in in-vehicle networks. Compared to conventional SeCOC, our modified protocol integrates timestamp-based freshness values to ensure uniqueness and mitigate replay attacks. Additionally, a three-layer authentication mechanism is introduced, combining digital signatures (RSA-2048), HMAC-based message integrity (SHA-256), and symmetric key encryption (AES-GCM) to authenticate communication at multiple levels. Our enhanced protocol demonstrates a 10% CPU cycle reduction and 12% improvement in response time, while maintaining low communication overhead (5%) and an average system latency of 3 ms. Security evaluation results indicate a 95% threat detection rate with a 2% false positive rate, showcasing its robustness in preventing message injection, manipulation, and replay attacks. These modifications make the protocol scalable, energy-efficient, and compatible with modern resource-constrained automotive systems, exceeding current industry cybersecurity standards.