Combining components and policies

Several mathematical models have been developed which describe various kinds of composition for secure systems. These models can be complex and unsatisfactory in the sense that it is difficult for a system designer to determine exactly how to connect components together to achieve a particular (security) property. We provide a simple mathematical model which we use to describe security policies and components. The model provides a means for describing the combination of both components and policies and for showing whether combinations of components will satisfy specified policies. If the system designer can describe a system in the terms we present, then the designer can use these terms to analyze some of the security properties of the system.<>