A single-level scheduler for the replicated architecture for multilevel-secure databases

The replicated architecture for multilevel secure database systems provides security by replicating data into separate untrusted single-level database systems. To be successful, a system using the replicated architecture must have a concurrency and replica control algorithm that does not introduce any covert channels. Jajodia and Kogan (1990) have developed one such algorithm that uses update projections and a write-all replica control algorithm. The authors describe an alternative algorithm. The new algorithm uses replicated transactions and a set of queues organized according to security class. A new definition of correctness is required for this approach, so they present one and use it to show that the algorithm is correct. The existence of this new algorithm increases the viability of the replicated architecture as an alternative to kernelized approaches