Biblio

This work describes a top down systems security requirements analysis approach for understanding and eliciting security requirements for a notional small unmanned aerial system (SUAS). More specifically, the System-Theoretic Process Analysis approach for Security (STPA-Sec) is used to understand and elicit systems security requirements. The effort employs STPA-Sec on a notional SUAS system case study to detail the development of functional-level security requirements, design-level engineering considerations, and architectural-level security specification criteria early in the system life cycle when the solution trade-space is largest rather than merely examining components and adding protections during system operation or sustainment. These details were elaborated during a semester independent study research effort by two United States Air Force Academy Systems Engineering cadets, guided by their instructor and a series of working group sessions with UAS operators and subject matter experts. This work provides insight into a viable systems security requirements analysis approach which results in traceable security, safety, and resiliency requirements that can be designed-for, built-to, and verified with confidence.

Today's highly interconnected and technology reliant environment places great emphasis on the need for secure cyber-physical systems. This work addresses this need by detailing a top down systems security requirements analysis approach for understanding and eliciting security requirements for a notional space system. More specifically, the System-Theoretic Process Analysis approach for Security (STPA-Sec) is used to understand and elicit systems security requirements during the conceptual stage of development. This work employs STPA-Sec in a notional space system to detail the development of functional-level security requirements, design-level engineering considerations, and architectural-level security specifications early in the system life cycle when the solution trade-space is largest rather than merely examining components and adding protections during system operation, maintenance, or sustainment. Lastly, this approach employs a holistic viewpoint which aligns with the systems and software engineering processes as detailed in ISO/IEC/IEEE 152SS and NIST SP SOO-160 Volume 1. This work seeks to advance the science of systems security by providing insight into a viable systems security requirements analysis approach which results in traceable security, safety, and resiliency requirements that can be designed-for, built-to, and verified with confidence.

Trust is an important topic in today's interconnected world. Breaches of trust in today's systems has had profound effects upon us all, and they are very difficult and costly to fix especially when caused by flaws in the system's architecture. Trust modeling can expose these types of issues, but modeling trust in complex multi-tiered system architectures can be very difficult. Often experts have differing views of trust and how it applies to systems within their domain. This work presents a graph-based modeling methodology that normalizes the application of trust across disparate system domains allowing the modeling of complex intersystem trust relationships. An algorithm is proposed that applies graph theory to model, validate and evaluate trust in system architectures. Also, it provides the means to apply metrics to compare and prioritize the effectiveness of trust management in system and component architectures. The results produced by the algorithm can be used in conjunction with systems engineering processes to ensure both trust and the efficient use of resources.

Today's highly interconnected and technology reliant environment places greater emphasis on the need for dependably secure systems. This work addresses this problem by detailing a systems security analysis approach for understanding and eliciting security requirements for complex cyber-physical systems. First, a readily understandable description of key architectural analysis definitions and desirable characteristics is provided along with a survey of commonly used security architecture analysis approaches. Next, a tailored version of the System-Theoretic Process Analysis approach for Security (STPA-Sec) is detailed in three phases which supports the development of functional-level security requirements, architectural-level engineering considerations, and design-level security criteria. In particular, these three phases are aligned with the systems and software engineering processes defined in the security processes of NIST SP 800-160. Lastly, this work is important for advancing the science of systems security by providing a viable systems security analysis approach for eliciting, defining, and analyzing traceable security, safety, and resiliency requirements which support evaluation criteria that can be designed-for, built-to, and verified with confidence.