Industrial Control Systems Testbed And Method Study Of The Encrypted Controller

In recent years,due to the frequently happened security incidents related to industrial control systems,researchers have been aware of the importance and urgency of enhancing the security of the industrial control systems.Researchers have carried out a lot of research work in order to enhance the security of the industrial control systems.Specifically,as a novel and promising method,the encrypted controller encrypts both signals transmitted over communication channels and the control law,so as to protect all information of a plant and its controller from attackers.However,the existing work about the encrypted controller mainly focuses on the theoretical research such as schematic design,which lacks the engineering realization and the experimental research under practical conditions.Therefore,in this thesis,we build up a security testbed of industrial control systems and carry out the experimental research of the encrypted controller.The main contents of the thesis are as follows:(1)In this thesis,we design and build a security testbed of industrial control systems for the experimental research of the encrypted controller.The testbed consists of five parts:the controller,the plant,the encryption/decryption unit,the communication networks,and the upper computer.For the convenience of the research in the testbed,we provide a framework for rapid application development.Meanwhile,the functionality of the testbed is tested in the thesis.(2)Considering the existing work about the encrypted controller mainly focuses on theoretical research,it is important to carry out the practical implementation and the experimental research of the encrypted controller in the testbed.Firstly,we implement three encrypted controller that encrypts the standard PID algorithm,industrial PID algorithm,and LQG algorithm respectively.Then,we verify and evaluate the encrypted controller method by using the encrypted controller implementation and a quadruple water tank system in the testbed.(3)In order to improve the security of the industrial control system which comprises the encrypted controller,we utilize the testbed as a tool and study in the system-level improvements.To solve the problem that the encrypted controller is hard to respond to attacks actively,we propose an improving scheme that combines the encrypted controller with the intrusion detection system.The effectiveness of the scheme is verified by carrying out attack and defense experiments in the testbed.Besides,we discuss the existing problems as well as improvement ideas in the method-level.