Multilevel Secure Transaction Processing: Status and Prospects

Since 1990, transaction processing in multilevel secure database management systems (DBMSs) has been receiving a great deal of attention from the database research community. Transaction processing in these systems requires modiication of conventional scheduling algorithms and commit protocols. These modiications are necessary because preserving the usual transaction properties when transactions are executing at diierent security levels often connicts with the enforcement of the security policy. Considerable eeort has been devoted to the development of eecient, secure algorithms for the major types of secure DBMS architectures: kernelized, repli-cated, and distributed. An additional problem that arises uniquely in multilevel secure DBMSs 2 Multilevel Secure Transaction Processing: Status and Prospects is that of secure, correct execution when data at multiple security levels must be written within one transaction. Signiicant progress has been made in a number of these areas, and a few of the techniques have been incorporated into commercial trusted DBMS products. However, there are many open problems remain to be explored. This paper reviews the achievements to date in transaction processing for multilevel secure DBMSs. The paper provides an overview of transaction processing needs and solutions in conventional DBMSs as background, explains the constraints introduced by multilevel security, and then describes the results of research in multilevel secure transaction processing. Research results and limitations in concurrency control, multilevel transaction management, and secure commit protocols are summarized. Finally, important new areas are identiied for secure transaction processing research.