Issues in distributed database security

The requirements for multilevel security have been shown to conflict with some database integrity and consistency properties. The authors examine the data consistency requirements for a distributed database system, consider the effects of multilevel security on meeting those requirements, and consider architecture for achieving them. They discuss the problem of providing serializability in a single-site database system and propose a solution based on optimistic concurrency control. They then extend this solution to a distributed database system. They also describe an approach for weak consistency concurrency control in a distributed database system based on the Optimistic Protocol