I. Introduction
Cyber-physical systems (CPSs), as the networked system that integrates physical and networked components to enable real-time monitoring, have attracted much attention in recent years. It has a flexible structure that provides greater autonomy, efficiency, and reliability because of the integration of physical entities and networks [1]. Due to these advantages and with the flourishing development of control, communication, and computation technologies, CPSs have attracted much attention. Especially, numerous theoretical results of CPSs have been obtained and applied in many engineering applications in the past decade, such as smart grids [2], robot control systems [3], and other advanced fields. For example, in [4], a novel distributed filter was proposed to solve the distributed recursive filtering problem for CPSs, and the effectiveness of the method was verified by applying it to a standard IEEE 39-bus power system. In contrast to traditional physical systems, the physical components of the CPSs can be adequately coordinated and controlled through key components, such as networks and control centers. However, communication networks and increasingly complex system architectures pose increasing challenges [5]. While introducing communication and computing components to ensure greater flexibility and scalability, it is also important to ensure the reliability of interactions between the components of the CPSs and the security of the CPSs under malicious cyber attacks. Therefore, the security and reliability of CPSs are getting more and more attention [6].