Ensuring Security and Availability through Model-Based Cross-Layer Adaptation

Situationand resource-aware security is essential for the process control systems, composed of networked entities with sensors and actuators, that monitor and control the national critical infrastructure. However, security cannot be addressed at a single layer because of the inherent dependencies and tradeoffs among crosscutting concerns. Techniques applied at one layer to improve security affect security, timing, and power consumption at other layers. This paper argues for an integrated treatment of security across multiple layers of abstraction (application, middleware, operating system including network stack, and hardware). An important step in realizing this integrated treatment of situationand resource-aware security is first understanding the cross-layer interactions between security policies and then exploiting these interactions to design efficient adaptation strategies (i) to balance security, quality of service, and energy needs, and (ii) to maximize system availability. We propose a novel approach that employs a compositional method within an iterative tuning framework based on lightweight formal methods with dynamic adaptation.