| On the road of the development of intelligent networked vehicles,the upgrade function of vehicle networking has gradually become one of the indispensable technologies.Enterprises have opened the OTA upgrade function in their respective models to continuously improve the driving experience and driving safety performance for users.Usually,the life cycle of software in in-vehicle equipment can accompany the vehicle for a long time,but now car developers can remotely upgrade the code of invehicle equipment using the interface that the car opens to the outside world by means of vehicle networking.These increasing numbers of open interfaces also bring serious security risks.Some unscrupulous persons can use wireless communication technology or the diagnostic interface of the physical connection to the vehicle to launch various attacks on the car,and even in serious cases the behavior of directly manipulating the car affects the life safety of consumers.Therefore,with the development of various emerging technologies,how to ensure the user’s driving safety and privacy is also a very important issue,because it is the most important issue that all smart cars can bring to users.The cornerstone of a beautiful and comfortable experience is an indispensable key link on the road of automobile intelligence.In the history of automobile development,bus technology occupies a very important part.Because the life cycle of a car is very long,the on-board equipment and electronic control unit ECU carried in it should have high reliability,and the bus technology and on-board network technology are to better solve the communication between the ECUs in the car,and Nowadays,the CAN bus communication protocol,which is widely used in the car,has many advantages.It can well meet the real-time and reliability of the communication between the nodes in the car while using a simple and cheap hardware.It is urgently needed for the in-vehicle network.However,even in the past few decades,the CAN bus protocol has been widely used,it still has some design deficiencies,lacks some identity verification mechanisms for online devices,and does not have an effective means to protect the transmission in the bus,which is based on broadcast-based data dissemination and the existence of data packets in plaintext are its two serious flaws.In other words,in the current era,the in-vehicle CAN network cannot meet some vehicle security requirements very well.The abovementioned vulnerabilities related to information security can be exploited by some people in a low-cost way,so that the history of hacking attacks against these vulnerabilities is almost impossible and it never stopped.Hackers can use these vulnerabilities to randomly change and forge the nodes and data in the vehicle network.Therefore,in the automotive OTA upgrade technology,the above defects of the CAN network should be protected and a method that can ensure the identity authentication and transmission of each node during communication should be designed.This paper analyzes the security requirements related to the communication between the nodes in the vehicle in the OTA upgrade scenario of the intelligent networked vehicle,and combines the different security risks faced in this process to conclude that the information security in the vehicle in this scenario should be based on the identity of the nodes.Authentication,how to ensure that privacy is not leaked during data transmission,and how to ensure that the data is correct and complete should be considered.In addition,relevant means to resist replay attacks and DOS attacks should be designed to prevent vehicles from being systematically risked and causing vehicles to be illegally controlled.Based on this idea,the main research contents of this paper include:（1）This paper analyzes the current development background of connected vehicles on intelligent roads and the advantages and information security risks brought by the vehicle OTA remote upgrade technology,and summarizes the research on information security mechanisms for the vehicle CAN bus communication environment at home and abroad.and overview.（2）After a systematic introduction to the CAN bus communication protocol,the limitations of information security and the threats it may face,such as wireless communication or physical access are listed.Information security requirements for communication between nodes,and then briefly summarizes several concepts and technical principles involved in automotive OTA upgrades,and proposes some information protection goals based on this specific scenario.（3）A digital certificate-oriented vehicle OTA upgrade in-vehicle node identity authentication and data encryption transmission mechanism based on CAN bus is proposed.The theoretical model and research design ideas are proposed based on some assumptions.Based on these assumptions,the in-vehicle nodes are analyzed.Different basic algorithms applicable to the data transmission node in the authentication phase and by redefining the content of the data field in the CAN data frame to achieve secure data transmission,the algorithms include the public key algorithm SM2 in the authentication phase and the key agreement algorithm based on ECC encryption,which can realize node identification and key exchange,and use a combination of symmetric encryption algorithm and digest algorithm in data communication to ensure the security of CAN network data transmission.（4）The identity authentication mechanism between the in-vehicle nodes in the OTA upgrade process of the vehicle is introduced in detail.First,the relevant principles of the national encryption algorithm SM2 based on the ECC curve are deeply analyzed.The national commercial encryption technology has the advantages of national independent research and development and can reduce the Relying on foreign related technologies,the algorithm is improved and developed in combination with related technical foundations,which has the advantages of higher performance and better security.On the other hand,the idea of challenge and response can well deal with replay attacks and provide higher security strength for authentication and data transmission between nodes in the vehicle.Secondly,it introduces the principle of key exchange technology in SM2 algorithm and how to use this technology to securely share encryption keys between nodes,which provides communication guarantee for data transmission.The implementation details of the symmetric encryption algorithm SM4 are analyzed in detail.The data security communication mechanism using the combination of the two algorithms is introduced in detail,which provides security guarantees such as data correctness,integrity and freshness for vehicle-mounted device communication.（5）A small CAN bus network with the functions of simulating in-vehicle gateway nodes and common ECU nodes is built to verify the identity verification and data encryption transmission functions between nodes using digital certificates and other mechanisms proposed above.The performance of certificate signature verification,key exchange,message digest generation,and data encryption and decryption,etc.,experiments show that the algorithm based on the national secret system adopted in this paper has good performance standards and can meet the requirements of resource-constrained embedded vehicle equipment environment.information security requirements in. |
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