The World is moving towards invisible computers, Ubiquitous Computing (any information everywhere), Pervasive Computing (which combines current network technology with wireless computing), Ambient Intelligence (which refers to electronic environments that are sensitive and responsive to the presence of people), and Traditional Embedded System (which is a closed system, not only in the sense of closed physical locations or dedicated hardware, but also closed with respect to the boundaries, where CPS (Cyber Physical Systems) is an open system which integrate computing and communication with monitoring and/or control of entities in physical world. CPS is the integration of several Wireless Sensor Networks.CPS is used in several applications like Automotive electronics, Avionics, Medical systems, Forestry machines, Logistics, Autonomous Vehicles, and

Cyber-Physical Systems (CPS) entail the tight integration of and coordination between computational and physical resources. These systems are increasingly becoming vital to modernizing the national critical infrastructure systems ranging from healthcare, to transportation and energy, to homeland security and national defense. Advances in CPS technology are needed to help improve their current capabilities as well as their adaptability, autonomicity, efficiency, reliability, safety and usability. Due to the proliferation of increasingly sophisticated cyber threats with exponentially destructive effects, CPS defense systems must systematically evolve their detection, understanding, attribution, and mitigation capabilities. Unfortunately most of the current CPS defense systems fall short to adequately provision defense services while maintaining operational continuity and stability of the targeted CPS applications in presence of advanced persistent attacks. Most of these defense systems use un-coordinated combinations of disparate tools to provision defense services for the cyber and physical components. Such isolation and lack of awareness of and cooperation between defense tools may lead to massive resource waste due to unnecessary redundancy, and potential conflicts that can

Abstract. In an interconnected cyber-world, Cyber-Physical Systems (CPSs) appear to play an increasingly important role in smart ecosys-tems. A variety of resource-constrained thin clients, such as sensors, RFIDs, actuators and smart devices, are included in the list of CPS. These devices can be used in a number of medical, vehicular, aviation, military and smart cities applications. A plethora of sensitive data is transmitted in insecure wireless or wired environments whilst adversaries are eager to eavesdrop, modify or destroy sensed data invading the pri-vacy of user-centric CPSs. This work presents an overview and analysis of the most effective attacks, privacy challenges and mitigation techniques for preserving the privacy of users and their interconnected devices. In order to preserve privacy, a privacy-level model is proposed in which users have the capability of assigning different privacy levels based on the va-riety and severity of privacy challenges and devices ’ capabilities. Finally, we evaluate the performance of specific CPSs at different privacy-levels in terms of time and consumed energy in an experimental test-bed that we have developed.