Achieving Database Security through Data Replication: the Sintra Prototype

There are several proposed approaches for multilevel secure (MLS) database systems which protect classi ed information. The SINTRA database system, which is currently being prototyped at the Naval Research Laboratory, is a multilevel trusted database system based on a replicated data approach. This approach uses physical separation of classi ed data as a protection measure. Each database contains data at a given security level and replicas of all data at lower security levels. Project goals include good performance and full database capability. For practical reasons (e.g., ease of evaluation, portability) the SINTRA database system uses as many readily-available commercial components as possible. In this paper, security constraints and the rationale for the SINTRA prototype are described. We also present the structure and function of each component of the SINTRA prototype: the global scheduler, the query preprocessor, and the user interface. A brief description of the SINTRA recovery mechanism is also presented.