A Dynamic Coding Scheme for Preventing Controllable Cyber-Attacks in Cyber-Physical Systems
Mahdi Taheri, K. Khorasani, Nader Meskin · 2024
Controllable attacks are considered as perfectly undetectable cyber-attacks that are performed by compromising input communication channels of cyber-physical systems (CPS). They are referred to as perfectly undetectable since they have zero impact on the sensor measurements of the system. In this paper, we investigate conditions under which adversaries are capable of performing controllable cyberattacks and develop methods for designing these attack signals. Moreover, under certain assumptions, conditions for designing controllable attacks in terms of the Markov parameters of the CPS are derived. In order to analyze the vulnerability of the CPS to controllable attacks from the system operators’ point of view, a security metric designated as the security effort (SE) for controllable attacks is formally defined and proposed. The SE for controllable attacks denotes the minimum number of input communication channels that need to be secured to prevent adversaries from executing this type of cyberattack. Consequently, as a countermeasure, we develop a coding scheme on the input communication channels that increases the minimum number of required input communication channels for performing controllable attacks to its maximum possible value. Consequently, in presence of the proposed coding scheme, adversaries need to compromise all the input communication channels to execute controllable attacks. Therefore, securing only one input channel prevents adversaries from performing controllable cyber-attacks. Finally, an illustrative numerical case study is provided to demonstrate the effectiveness and capabilities of our derived conditions and proposed methodologies.