We present a control-theoretic approach to achieve Cyber-Physical Systems (CPS) resilient designs. We assume situations in which the CPS must maintain the correct operation of a set of crucial functionalities despite ongoing adversarial misbehavior. The approach is based on a moving target defense paradigm, driven by a linear switching of state-space matrices, and applied at both the physical and network layers of a networked-control system. We show that the final system maintains stability. We also evaluate, via simulation, a step-by-step procedure that takes a transfer function, representing the dynamics of the physical process. As a result, we obtain a resilient CPS design structured around a topology of decentralized controllers. Results show that the obtained approach is both innovative and promising.

Information systems of companies and organizations are increasingly designed using web services that allow different applications written in different programming languages to communicate. These systems or some parts of them are often outsourced on the cloud, first to leverage the benefits of cloud platforms (e.g., scalability) and also to reduce operational costs of companies as well. However, web services as well as cloud platforms may be the target of attacks that alter their security, and the security of web services is not completely addressed. The solutions proposed in the literature are sometimes specific to certain types of attacks and they cannot ensure the attack tolerance of web services. Attack tolerance can be defined as the capability of a system to function properly with minimal degradation of performance, even if the presence of an attack is detected. As such, we claim that, to achieve attack tolerance, one should detect attacks by a continuous monitoring and mitigate the effects of these attacks by reliable reaction mechanisms. For this aim, an attack tolerance framework is proposed in this paper. This framework includes the risks analysis of attacks and is based on diversification and software reflection techniques. We applied this framework to cloud applications that are based on web services. After describing the core foundation of this approach, we express such cloud applications as choreographies of web services according to their distributed nature. The framework has been validated through an electronic voting system. The results of these experiments show the capability of the framework to ensure the required attack tolerance of cloud applications.

Digital Twin (DT) is one of the pillars of modern information technologies that plays an important role on industry's digitalization. A DT is composed of a real physical object, a virtual abstraction of the object and a bidirectional data flow between the physical and virtual components. This paper presents a DT-based tool, called TaS, to easily test and simulate IoT environments. The objective is to improve the testing methodologies in IoT systems to evaluate the possible impact of it on the physical world. We provide the conditions to test, predict errors and stress application depending on hardware, software and real world physical process. The tool is based on the DT concept in order to detect and predict failures in evolving IoT environments. In particular, the way to prepare the DT to support fault injection and cybersecurity threats is analyzed. The TaS tool is tested through an industrial case study, the Intelligent Transport System (ITS) provided by the INDRA company. Results of experiments are presented that show that our DT is closely linked to the real world.

No abstract

No abstract