Assurance Oriented Hardware Decomposition: A Deterministic Approach to Security Assurance

Security assurance for modern hardware systems requires reasoning that is traceable, repeatable, and grounded in documented architectural structure. However, existing assurance practices provide limited methodological support for deterministically transforming heterogeneous engineering documentation into structured assurance representations. This paper presents Assurance Oriented Hardware Decomposition (AHD), a multi-phase methodology for deriving assurance-relevant artefacts from documentation through semantics guided and provenance preserving transformations. AHD reconstructs assurance obligations, exposure boundaries, feasibility conditions, and consolidated assurance execution units using a formal knowledge base that enforces rule governed and reproducible reasoning. An evaluation across three heterogeneous hardware systems examines the methodological behavior of AHD under varied architectural and documentary conditions. The results indicate that the methodology produces stable and coherent assurance structures that reflect differences in system architecture and documentation characteristics. These findings suggest that deterministic, evidence grounded decomposition, supported by bounded AI annotation, provides a structured foundation for hardware assurance reasoning without asserting security effectiveness.