Review of Fuzzy Methods Application in IIoT Security—Challenges and Perspectives

Traditional methods often fail when confronted with data characterised by uncertainty, incompleteness, and dynamically evolving threats within the Industrial Internet of Things (IIoT) environment. This paper presents the role of fuzzy set methods as a response to these challenges in ensuring IIoT security. A systematic literature review reveals how fuzzy set methods contribute to supporting and enabling actions ranging from anomaly detection to risk analysis. The work focuses on fuzzy systems such as the Fuzzy Inference System (FIS) and the Adaptive Neuro-Fuzzy Inference System (ANFIS), highlighting their strengths, including their resilience to imperfect data and the intuitiveness of their rules. It also identifies challenges related to optimisation and scalability. The article outlines directions for further research, indicating the potential of fuzzy methods as a cornerstone of future, intelligent IIoT cyber defence systems, capable of effectively responding to complex and changing attack scenarios.