Sporadic Authenticated Encryption on CAN-Bus: A Low-Cost Secure Method

The increasing complexity of modern vehicles and the widespread adoption of the Controller Area Network (CAN) Bus have amplified the need for efficient, low-cost security protocols to protect in-vehicle networks (IVNs) from cyberattacks. In this paper, we introduce the Sporadic Authenticated Encryption (SAE) method, a novel approach to securing CAN-Bus communication against replay, sniffing, and spoofing attacks. Unlike traditional methods which authenticate all messages or rely on fixed authentication intervals, SAE dynamically adjusts the interval of message authentications based on the Lyapunov stability, ensuring the system stability even in adverse conditions. Through extensive simulations, we demonstrated significant improvements of SAE over existing methods, achieving a 19% reduction in high-priority message delays and up to 23% improvement in low-priority message delays in comparison to the periodic authentication schemes. By leveraging Lyapunov theory, SAE optimally schedules authenticated messages while maintaining the system stability and reducing the communication overhead. Moreover, SAE ensures schedulability under worst-case conditions, guaranteeing the timely delivery of all messages. These results position SAE as a robust and practical solution for enhancing security and stability in resource-constrained automotive networks.