Design and implementation of a distributed database

We describe an approach for controlling certain unauthorized inferences in a multilevel secure distributed database management system. In such a system, two or more multilevel secure database management systems are connected via a trusted network. Furthermore, the environment that we have considered is a limited heterogeneous one where not all of the nodes handle the same accreditation ranges. In our approach, security constraints, which are rules that assign security levels to the data, are processed during the distributed query, update, and database design operations in such a way that users do not acquire information to which they are not authorized via logical deductions. We describe the design and implementation of the distributed inference controller which functions during the query operation.<>