Implementation Example: Silverfish

Abstract

Digital engineering is seeing increased applications in the conception, design, integration, verification and validation (V&V) of mission critical systems. As a greater number of safety and security considerations are included in the design process, mission systems, network architecture design, and verification have become increasingly complex. The Department of Defense (DoD) Cyber Resilient Weapon Systems (CRWS) initiative encourages a mission-level analysis of system vulnerabilities and potential adversary actions to evaluate mission resilience to cybersecurity effects. The research, and resulting use case, is focused on transition of an end-to-end systems engineering methodology intended to close the loop between mission-level resilience analysis and system development activities using digital engineering processes. In particular, the research offers an approach to model safety and security decisions, which are negotiations, into the system design model.

This use case presents both a novel and practical application of model-based system assurance methodologies. The methods, practices, and tools assess the quality of different requirements and design solutions based on safety and security risks in the presence of a determined cyberattack. The methods trade requirements and design decisions based on evaluation of hazard/risk, cost, and threat adversary properties. These methods also consider the dependencies between cybersecurity and system safety. In the cybersecurity domain, traditional assurance processes are inadequate, and further development is needed on new metrics, methods, and tools for hazard mitigation. In the context of digital engineering, finding the right approach to computationally support systems engineering and engineering activities of requirements, architecture, design, verification and validation for end-to-end solutions in the context of the mission is essential.

The full link from mission engineering to system requirements to design using formal modeling and dynamic simulations of the system is currently not well integrated. Transition to common standards, methods and processes, and tools and techniques are needed. This use case, based off Chapters 22–27, presents an opportunity to unify and standardize approaches to model-based systems assurance and mission engineering through formal modeling and dynamic simulations.

As a mechanism to guide understanding of the research (Mission Aware components [STPA-Sec, CSRM, Meta-Model and MBSE] and FOREST), a case study is presented. The case study clarifies how programs can design in cyber resilience to create more resilient system solutions through holistic consideration of associated requirements, engineering trade-offs, and quality attributes. The use case is organized by the CSRM steps and FOREST.