The University of British Columbia

Traditional authorization mechanisms based on the request-response model are generally supported by point-to-point communication between applications and authorization servers. As distributed applications increase in size and complexity, an authorization architecture based on point-to-point communication becomes fragile and difficult to manage. This paper presents the use of the publish-subscribe (pub-sub) model for delivering authorization requests and responses between the applications and the authorization servers. Our analysis suggests that using the pub-sub architecture improves authorization system availability and reduces system administration overhead. We evaluate our design using a prototype implementation, which confirms the improvement in availability. Although the response time is also increased, this impact can be reduced by bypassing the pub-sub channel when returning authorizations or by caching coupled with local inference of authorization decisions based on previously cached authorizations.