As a sensor with mature holographic sensing technology and low cost, millimeter wave radar has been widely used in Blind Spot Detection (BSD) and Adaptive Cruise Control (ACC) of autonomous vehicles. Millimeter wave radar receives vehicle speed and angular velocity information from Controller Area Network (CAN) bus, and sends sensor sensing information to CAN bus constantly. This operation principle brings security threats to autonomous vehicles for attackers could transmit false information to Electronic Control Units (ECUs) and in-vehicle sensors. This paper proposes a security protection method based on digital watermarking for the communication between in-vehicle millimeter wave radar sensor and ECUs. The method can verify data integrity without increasing in-vehicle network load and prevent tamper attack effectively. In this method, the redundant bits of CAN bus communication data are embedded into the digital watermarking information, and the digital watermarking is extracted and checked at the end of receiving data to judge whether the data is complete or tampered with. We simulate this method on embedded devices and the simulation results show that the method can prevent tamper attack of the communication between millimeter wave radar sensor and ECUs effectively.

in-vehicle network;cyber security;digital watermarking;millmeter wave radar