Authorization specification and enforcement in Federated Database systems

A federated system is a collection of cooperating autonomous databases. Federated systems represent today one of the new emerging technologies for data management. This success comes from the need to integrate and work on different existing systems that have been developed and have evolved independently. The necessity of making them available to users as if they were a single system, while at the same time not affecting their independent working, arises several issues with respect to authorization management and specification and to access control enforcement. In this paper we discuss some of these issues and present an authorization model for the specification and enforcement of authorizations in federated database systems. The model allows users to make their data available to the federation and to choose among different administrative policies for regulating the specification of authorizations.