Security system architecture governs the composition of components in security systems and interactions between them. It
plays a central role in the design of software security systems that ensure secure access to distributed resources in networked
environment. In particular, the composition of the systems must consistently assure security policies that it is supposed to enforce.
However, there is currently no rigorous and systematic way to predict and assure such critical properties in security system design. In
this paper, a systematic approach is introduced to address the problem. We present a methodology for modeling security system
architecture and for verifying whether required security constraints are assured by the composition of the components. We introduce
the concept of security constraint patterns, which formally specify the generic form of security policies that all implementations of the
system architecture must enforce. The analysis of the architecture is driven by the propagation of the global security constraints onto
the components in an incremental process. We show that our methodology is both flexible and scalable. It is argued that such a
methodology not only ensures the integrity of critical early design decisions, but also provides a framework to guide correct
implementations of the design. We demonstrate the methodology through a case study in which we model and analyze the architecture
of the Resource Access Decision (RAD) Facility, an OMG standard for application-level authorization service.
IEEE Transactions on Knowledge and Data Engineering 15(5):1099-1119