Preservation of Policy Adherence under Refinement

Policy-basedmanagement is an approach to the management of sys-tems with respect to issues such as security, access control and trustby the enforcement of policy rules. This paper addresses the problemof integrating the requirements imposed by a policy with the systemdevelopment process. In order to take a policy specification into ac-count in the development of a system specification, the notion of policyadherence is formalized as a relation between policy specifications andsystem specifications. Adherence of a system specification to a policyspecification means that the former satisfies the latter. The integrateddevelopment process is supported by refinement, where both the policyspecification and the system specification may be developed under anynumber of refinement steps. This paper characterizes the conditionsunder which adherence is preserved under refinement and identifies de-velopment rules that guarantee adherence preservation. By results oftransitivity and compositionality the integrated development processand the analysis tasks can be conducted in a stepwise and modularway, thereby facilitating development.