Research On Information Security Defense Based On Multi-stage Game In Train Control Systems

The urban rail transit train control system is a key system to ensure the safe and efficient operation of trains.With the continuous introduction of new technologies such as computers,signals,networks,and controls,the degree of automation and informatization of urban rail transit train control system has been unprecedentedly improved.However,the introduction of advanced general technology has also brought many information security risks and threats to the train control system.In recent years,information security accidents have occurred frequently in all walks of life,and the means of attack have become more and more complicated,and have begun to show obvious phase characteristics,traditional defense methods,such as firewalls,have been difficult to exert satisfactory defense effects.Information security attacks in traditional IT systems and industrial control systems are very different from those in train control systems,the "information-physical" characteristics of the system itself and the stage of the attack make the impact of information attacks on the train control system more complicated.At the same time,research on information security defense equipment designed for the network environment and business logic of train control systems is still in its infancy.In summary,the research on the complex attack defense methods of the train control system has both theoretical and practical significance.This thesis analyzes the complex information security attack scenario of train control system based on the characteristics of working principle of train control system of urban rail transit,network structure and security protection,and studies the active defense methods covering the entire process of train control system complex attack.In addition,for the two stages of information attack in train control systems,active defense methods based on attack path prediction and mobile target defense are designed,and the proposed scheme is simulated and verified combined with the minimum system.The main content of the thesis is as follows:(1)Combined with the urban rail transit train control system architecture and working principle,the information security risks and complex attack scenarios of the train control system are analyzed.Based on this,the requirements and overall framework for the active defense of complex information attacks in the urban rail transit train control system were proposed.Based on this,the requirements and overall framework for the active defense of complex information attacks in urban rail transit train control systems are proposed.(2)The defense method of the complex attack penetration stage of the train control system based on the attack path prediction is studied.The multi-layer game is used to establish the chain interaction process model of the attack and defense parties in the penetration stage.A quantitative method of attack and defense behavior in the penetration stage of the train control system is proposed and the calculation method and analysis process of game equilibrium are given.(3)The defense method of the complex attack destruction stage of the train control system based on mobile target defense is studied,and the terminal information hopping technology is innovatively introduced into the train control system.The destructive behavior defense mechanism based on IP hopping is designed,Based on the repeated game,a defensive strategy optimization model is established and Fictitious Play(FP)is used to solve the infinitely repeated game model.(4)The minimum system of urban rail transit train control system is established,and the two parts of the defense mechanism are simulated and analyzed to verify the effectiveness of the defense mechanism.Finally,the defense capabilities of the complex attack defense method of the train control system are analyzed from an overall perspective.34 charts,26 tables,73 references.