With the rapid development of ICV(Intelligent Connected Vehicle) industry, data exchange between vehicle and human, vehicle and vehicle as well as between vehicle and external environment has become nor mal, automobile safety has been seriously threatened, and it is very important to study automobile safety certification. Safety certification of vehicle-mounted PEPS (Passive Entry Passive Start) and EMS (Engine Management System) determines the safety performance of the vehicle, which is the prerequisite to ensure the safe operation of the vehicle. At present, 128bits AES algorithm is widely used in the industry to realize the security certification of PEPS and EMS. Because the AES key generation and key scheduling algorithm is more complex than the national encryption algorithm SM4, the encryption and decryption time is longer, and the amount of code implemented by the algorithm is larger, which takes up too much MCU resources. Therefore, it is proposed to apply the national secret SM4 algorithm to the safety certification of on-board PEPS and EMS, shorten the encryption and decryption time, and effectively improve the efficiency of data transmission. At the same time, the high level language is used to implement the algorithm and transplanted to the domestic MCU GD32F103 to realize localization of the product and reduce the cost. The state secret algorithm SM4 is extended to provide a research basis for ICV security certification.