Abstract: Modern vehicles are equipped with a large number of electronic devices， which may become a way for hackers to invade the vehicle network system. In order to prevent attacks， it is necessary to introduce a security mechanism for the CAN-FD vehicle bus. A CAN-FD hierarchical security model was established to distinguish signal， frame， and ECU-level security levels， based on frame AES encryption and adding MAC message authentication codes. According to the proposed model， a signal packaging safety constraint that can effectively reduce the hardware cost of ECU safety design was developed. By introducing the greedy algorithm into the crossover operator and mutation operator of the genetic algorithm， a safety-based hybrid genetic algorithm was designed to package and optimize CAN-FD signals with different safety levels. Experiments show that the hybrid genetic algorithm can achieve lower bandwidth utilization than the greedy algorithm， and the impact of this security design on bandwidth utilization is analyzed through experiments.

Key words: CAN-FD signal packing; layered security model; signal packaging security constraints; hybrid genetic algorithm