Authorization recycling in hierarchical RBAC systems

As distributed applications increase in size and complexity, traditional authorization architectures based on a dedicated authorization server become increasingly fragile because this decision point represents a single point of failure and a performance bottleneck. Authorization caching, which enables the reuse of previous authorization decisions, is one technique that has been used to address these challenges. This article introduces and evaluates the mechanisms for authorization “recycling” in RBAC enterprise systems. The algorithms that support these mechanisms allow making precise and approximate authorization decisions, thereby masking possible failures of the authorization server and reducing its load. We evaluate these algorithms analytically as well as using simulation and a prototype implementation. Our evaluation results demonstrate that authorization recycling can improve the performance of distributed-access control mechanisms.