Deriving and Formalising Safety and Security Requirements for Control Systems

Safety-critical control systems become increasingly open and interconnected. However, there is still a lack of the techniques that enable an integrated analysis of safety and security requirements. In this paper, we propose an approach that allows the designers to derive and formalise safety and security requirements in a structured systematic way. To elicit both types of the requirements, we adapt and integrate traditional safety and security analysis techniques. To formally specify and verify them, we rely on Event-B framework. The framework allows us to develop a complex specification of system behaviour in presence of both accidental faults and security attacks and analyse mutual interdependencies between safety and security requirements.