21 octobre 2026
Title: From Security to Utility in Cyber-Physical Systems: A Discrete Event Systems Approach
Abstract: Cyber-Physical Systems (CPS) seamlessly integrate computation, networking, and physical processes, giving rise to complex interconnected infrastructures where ensuring both security and operational performance is a paramount challenge. Formal methods based on Discrete Event Systems (DES) provide a mathematical foundation to model, analyze, and synthesize control strategies capable of guaranteeing safety and functional utility under adversarial conditions. In this context, this seminar begins with an overview of the research initiatives within the CAPES-COFECUB DeCyPhRA project, highlighting the collaborative efforts and expertise of the Brazilian team across the Federal University of Bahia (UFBA), the Federal University of Minas Gerais (UFMG), and the Federal University of Santa Catarina (UFSC). Turning to technical challenges, we examine how the classical Confidentiality, Integrity, and Availability (CIA) triad translates into discrete-event abstractions, followed by a comprehensive classification of cyber-attacks in DES covering active and passive adversarial behaviors. To address privacy, we explore Current-State Opacity (CSO) and Current-State Opacity based on State Outputs (CSO-SO) as formal mechanisms to mask sensitive states from eavesdroppers, while introducing state-based transparency as a novel utility formulation designed to quantify and preserve essential system functionality under security constraints. Finally, we address the integration of cryptography in DES and how to overcome communication synchronization issues in encrypted supervisory control architectures, concluding with automated recovery strategies that, after the detection of a malicious compromise, restore the system to safe operating conditions without sacrificing liveness.