Coordinated cyber-physical attacks (CCPA) have been touted as a serious threat for several years, where "coordinated" means that attackers have complete knowledge of the physical plant and status, and sometimes can even create physical defects, to assist cyber attacks, and vice versa. In recent years, these attacks have crept from theory to reality, with attacks on vehicles, electrical grids, and industrial plants, which have the potential to cause destruction and even death outside of the digital world. CCPA raise a unique challenge with respect to cyber-physical systems (CPS) safety. Historically, technologies to defend cyber attacks and physical attacks are developed separately under different assumptions and models. For instance, cyber security technologies often require the complete profile of the physical dynamics and the observation of the system state, which may not be available when physical defects exist. Similarly, existing system control techniques may efficiently compensate for the physical damage, but under the assumption that the control software and the sensor data are not compromised. There is a lack of unified approaches against CCPA. With this observation, this project focuses on the development of unified models with coherent set of assumptions, supported by integrated technologies, upon which CCPA can be defended much more effectively.

The project outcomes viewed from the perspectives of intellectual merit and broader of impacts are described below.

Intellectual Merit

Over the past four years, the project has established the theoretical foundations and engineering principles for resilient CPS architectures and investigated the unified models and platforms that represent the scientific understanding of resilient CPS against CCPA. The interdisciplinary research aimed at the predictable performance for resilient CPS, with the following targets:

• significantly enhanced levels of safety and security of CPS in highly unpredictable and adversary environments;
• a significant reduction in the verification time of CPS from hours to seconds;
• reliable sensor samplings and cyber-physcial communications, 
• efficient CPS recovery from CCPA.

Broader of Impacts

The technological advancements resulting from this project can be transfered to industrial use cases to build new CPS infrastructure in the modern society, greatly promoting industrial automation and boosting economy. For example, the L₁Simplex framework can be directly applied to the industrial, commercial, military and civilian aircraft, vehicles and unmanned systems to enhance system security and safety. The PIs are actively engaged in NASA, DOD, and industrial research. The PIs have promoted awareness of the research results through publications, conferences, workshops, and seminars, for education of a broader audience beyond UIUC.

To achieve the goals of the project, the group led by PI Naira Hovakimyan, Co-PI Petros Voulgaris and Co-PI Lui Sha over the past four years has developed  (1) a container-based attack-resilient Simplex architecture which provides strong separation between the high-performance and high-assurance controllers while maintaining reliability, (2) L₁ sampled-data adaptive controller with the integration of Simplex fault-tolerant architecture for resilient control of cyber-physical systems, (3) an advanced attack-resilient estimation algorithm for given state and input constraints, (4) a resilient control framework for single UAV as well as the multi-agent time-critical coordination network against GPS spoofing attacks, and (5)  a new security measure and escape time for resilient UAVs with respect to GPS spoofing attacks. Meanwhile, the group has introduced a new class of stealthy attacks and corresponding detection and defense mechanisms for networked CPS. The proposed frameworks of detection and mitigation of attacks were validated in flight tests of a quadrotor in Intelligent Robotics Laboratory of UIUC.

Last Modified: 12/20/2021
Modified by: Naira Hovakimyan