Reliable and Secure Design-Space-Exploration for Cyber-Physical Systems

Abstract

Given the widespread deployment of cyber-physical systems and their safety-critical nature, reliability and security guarantees offered by such systems are of paramount importance. While the security of such systems against sensor attacks have garnered significant attention from researchers in recent times, improving the reliability of a control software implementation against transient environmental disturbances need to be investigated further. Scalable formal methods for verification of actual control performance guarantee offered by software implementations of control laws in the face of sensory faults have been explored in recent work [20]. However, the formal verification of the improvement of system reliability by incorporating sensor fault mitigation techniques like Kalman filtering [29] and sensor fusion [18, 52] remains to be explored. Moreover, system designers face complex tradeoff choices for deciding upon the usage of fault and attack mitigation techniques and scheduling them on available system resources as they incur extra computation load. In the present work, our contributions are threefold. We formally analyze the actual performance guarantee of control software implementations enabled with additional fault mitigation techniques. We consider task-level models of such implementations enabled with security and fault tolerance primitives and construct a timed automata-based model which checks for schedulability on heterogeneous multi-core platforms. We leverage these methodologies in the context of a novel Design-Space-Exploration (DSE) framework that considers target reliability and security guarantees for a control system and computes schedulable design options while considering well-known platform-level security improvement and fault mitigation techniques. We validate our contributions over several case studies from the automotive domain.