Concepts of Trust and Resilience in Cyber‐Physical Systems

System assurance is the confidence that a system functions as intended and is secure from vulnerabilities, whether intentional or unintentional. Cyber‐Physical Systems (CPS) are vulnerable to new types of threats due to their interconnected computing and communication backbone. Designing resilient CPS involves ensuring security, functionality, and interconnectedness. System trust is based on the mutual assurance between interconnected systems. System assurance requires a comprehensive systems engineering approach covering system structure, engineering processes, and supporting models and techniques for evidence‐based judgments. This chapter examines historical and evolving methods for system assurance in CPS. Old assurance methods are no longer suitable for today's complex systems and new tools are needed. The chapter reviews traditional assurance practices and their limitations and discusses the need for improved practices through functional and formal design methods. Other chapters elucidate research efforts that explore (1) system architectures for achieving resilience, (2) system methodologies, frameworks, and analysis tools for prioritizing resilience solutions, (3) the roles and procedures for engaging operators in the real‐time management of system reconfigurations that provide resilience, and (4) designing in resilience through the engineering process.