What is Covert Channel

Transaction-processing systems (TPS) are becoming increasingly more available as commercial products. However, the approaches to the issues associated with using TPS in multilevel secure environments are still in the research stage. In this article, we address the issues of multilevel security in distributed transaction-processing systems. A distributed transaction-processing system (DTPS) is a collection of a finite number of centralized transaction-processing systems connected by a computer network. Each of these transaction- processing systems is controlled by a software layer and can be accessed both remotely and locally. Properties of a DTPS, such as data replication, may have a substantial effect on the security of the system. The security policies and integrity constraints adopted at each site may result in global security having inconsistent states. We address the issues of achieving a multilevel secure DTPS, and discuss the security constraints and data replication. In this work, we address the issues of achieving a multilevel secure DTPSs system and discuss the security constraints and the replication of data items. The next section provides some background. Then, next, an overview of a distributed transaction-processing system is presented. In the fourth section, security-related issues are discussed. In the fifth section, a multilevel secure distributed transactionprocessing system is presented. Then, in the next section, future trends are presented. The final section concludes the article.