Date Added: Apr 2013
Collaborative applications have lately gained extra momentum due to two recent phenomena: data explosion and cloud computing. With more and more data and applications being hosted in the ''Cloud'', it becomes easier for organizations with varying levels of mutual trust to share and collaborate over resources. However, a pressing challenge remains with the need of each organization to control access to its resources. Authorization, usually implemented as Role-Based Access Control (RBAC), has been recently proposed as a consolidated, multi-tenant cloud service, whereby RBAC rules of the collaborating organizations are stored centrally with a trusted authorization provider to mask heterogeneity and to simplify management.