Biblio

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.

Information flow security has been considered as a critical requirement on complicated component-based software. The recent efforts on the compositional information flow analyses were limited on the expressiveness of security lattice and the efficiency of compositional enforcement. Extending these approaches to support more general security lattices is usually nontrivial because the compositionality of information flow security properties should be properly treated. In this work, we present a new extension of interface automaton. On this interface structure, we propose two refinement-based security properties, adaptable to any finite security lattice. For each property, we present and prove the security condition that ensures the property to be preserved under composition. Furthermore, we implement the refinement algorithms and the security condition decision procedure. We demonstrate the usability and efficiency of our approach with in-depth case studies. The evaluation results show that our compositional enforcement can effectively reduce the verification cost compared with global verification on composite system.