Message Integrity and Authenticity in Secure CAN

Existing vehicles and emerging smart vehicles organize their architecture around a controller area network (CAN) bus. Control messages with commands from one component cause another component to take an action. If a control message and action resulting from it is recorded by an adversary, it might be replayed for the same action. A connected smart vehicle is vulnerable to new attack vectors originating from other systems within a smart community. Existing CAN protocol does not prevent replay attacks. We develop a secure CAN protocol. A shared secret between nodes allows for confidential and authenticated messages. Use of a freshness value and keyed hash offer message integrity and staleness prevention. The distributed (centralized) bandwidth of 958.5 (934.3125) Kb/s compares favorably with the CAN protocol. Base CAN-FD protocol without any security achieves $9.8\%$ higher bandwidth than the distributed secure CAN.