## 2 Smart Health and ICS as Critical Cyber Infrastructure  
Generally, and according to the IEEE [25], \"the IoT is a system consisting of networks of sensors, actuators, and smart objects whose purpose is to interconnect all things, including every day and industrial objects, in such a way as to make them intelligent, programmable, and more capable of interacting with humans and each other\". In addition, IoT is used in healthcare to monitor the physiological health parameters of patients. However, there is no standard or unified definition of the IoT in healthcare. Some definitions emphasize the technical aspects, whereas the others focus more on uses and features. With respect to healthcare, the IoT primarily manages and comprises a network of interconnected medical devices over the Internet to create smart healthcare environments [26]. Networked medical devices in smart health \"can be worn (wearables) or implanted inside the body, for example, pacemakers,\" thereby providing services using smart methods. For example, \"wearable health devices use an assortment of sensors to measure everything from heart rate, activity to sleep patterns and come equipped with communication capabilities. Such devices can form an IoT network for patient telemonitoring in hospitals and can also be used for home telemonitoring\" [27]. Healthcare applications are projected to have the highest economic impact [28]. IoT-based healthcare and manufacturing applications are technologies that are expected to significantly affect society, as illustrated in Figure 2[28]. An IoT-based healthcare system is a complex cyber infrastructure that deploys a range of devices and sensors that communicate discerningly across a fabric of heterogeneous, full distributed networks while providing ubiquitous services that are available at any place and time.This ecosystem of integrated care improves the quality of life for patients, reduces the time and the cost of care, and provides accurate and timely information to facilitate fast and effective decision-making and monitoring of patients with chronic diseases [29]. The key idea of IoT-based healthcare systems is the facilitation of useful functions via the \"always-on\" connectivity anywhere at any time for any patient [30], thereby providing remote diagnostics and treatment services, self-monitoring, and improving the quality of life by supporting a connected healthcare community. The objective of the IoT-based CPS is to collect, manage, and analyze sensor data regardless of the corresponding protocols, formats, or network technologies used [31]. The development of such a flexible and adaptable architecture is essential. To this end, the IoT architecture comprises several layers that communicate with each other to connect the physical and virtual worlds. This architecture comprises three layers: the sensors/actuators, control/command and supervision levels [32; 33; 34]. Different typologies of architectures can be found in the literature to describe CPS; however, the Computer Integrated Manufacturing architecture (CIM) [35] will be presented to describe the different hierarchical levels. Figure 3 shows the architecture of an IoT-based CPS infrastructure. Each level is made up of characteristic elements and exchanges information with the other levels. The breakdown of this architecture is as follows:  
Level 1 (Sensors--Actuators): In the perception layer, sensors are deployed in the perception layer to detect and collect environmental information. Thus, the perception layer is responsible for sensing and actuating physical processes, detecting certain physical parameters and identifying smart objects. Sensors and actuators make the link between the digital part and the physical part, forming the physical system. This level is also called the Operative Part (OP). The goal is to transform a raw material into a finished product via the production flow. Thus, the system brings the process from an initial state to a final state by acting on the production flow while guaranteeing productivity and reliability.