Implementation and evaluation of a method to defend in-vehicle networks using SAE J1939-91C to authenticate network messages between multiple ECUs.

The objective of this paper is to understand the effort required to integrate the hardware and software of in-vehicle cybersecurity systems. The in-vehicle cybersecurity method discussed is the SAE J1939-91C, which involves Network formation, Rekeying, and secure Message Exchange between Electronic Control Units (ECUs). The SAE J1939-91C network security protocol operates over a CAN-FD network to perform necessary cryptographic operations and key generation. To evaluate the method, test vectors were created to validate SAE J1939-91C key generations and cryptographic operations on the simulated ECU in-vehicle network system hardware. The evaluation results provide a benchmark for network system performance that can be used in a system test bench to assess compliance with the SAE J1939-91C standard and to test the standard's effectiveness in ambiguous edge cases. In the future, this benchmark could be utilized in "Plugtests" to assign test scores to non-uniform SAE J1939-91C implementations, aiding in improving system interoperability.