Research on information security technology based on hierarchical intelligent control system

With the advent of the information age, the field of industrial control has achieved rapid development. Industrial equipment is connected to each other through bus network, and the deployment is relatively dispersed. Due to the lack of sufficient security of bus protocol, intruders use the information security hidden danger of bus protocol to attack the system. Therefore, the research on information security of fieldbus protocol is of great significance for information security protection in industrial field. In this paper, starting from the theory and practice, the commonly used several kinds of fieldbus in the industrial control system, namely the Modbus/RTU, CAN, Mr CAT bus research and analysis. Firstly, the Petri net formalized modeling method was used to model and analyze the above bus respectively. Secondly, the accessibility analysis method was used to analyze and verify the boundedness, reversibility and initiative of the model. Finally, the correctness of the model was guaranteed. Aiming at the hidden trouble existing in the current bus protocol, the attack behavior is formally described by Petri net model. In the experiment part, Modbus/RTU, CAN and Ether CAT field buses are used to build a hierarchical intelligent control system to simulate the actual industrial control scene. The system is divided into decision layer, control layer and executive layer to realize the communication between each layer and the upper and lower layers. In order to simulate the behavior of attackers, several attack experiments were carried out, including flood attack, eavesdropping to steal data frames, man-in-the-middle attack and other attack methods, to disrupt the normal operation of the system and record the experimental results. Finally, a bus monitoring system is designed, taking CAN bus as the monitoring object. The system CAN conduct real-time monitoring of the state when CAN bus transmits data according to the flow of data frames, and meanwhile conduct data collection to identify illegal data frames, so as to realize information security protection of the control system to a certain extent.The focus of this paper is to use Petri net modeling analysis method to analyze and study several field buses, and through the attack experiment to analyze the bus system information security risks, hoping that the research content of this paper can provide theoretical reference for the design and security protection of industrial control system.