Toward Practical Authorization-dependent User Obligation Systems

Many authorization system models include some notion of obligation. Little attention has been given to user obligations that depend on and affect authorizations. However, to be usable, the system must ensure users have the authorizations they need when their obligations must be performed. Prior work in this area introduced accountability properties that ensure failure to fulfill obligations is not due to lack of required authorizations. That work presented inconclusive and purely theoretical results concerning the feasibility of maintaining accountability in practice. The results of the current paper include algorithms and performance analysis that support the thesis that maintaining accountability in a reference monitor is reasonable in many applications.