In 1988 we initiated our work on belief data. The work proceeded in two phases: in the first phase we formalized the concept of error in everyday record keeping, and in the second phase we considered multilevel security. The purpose of this report is to create an awareness about our works on belief data and to serve as a guide for the following manuscripts. The first two manuscripts are on the ...

Without proposing a new key assignment scheme, this paper presents a graph translation procedure that can be used to enforce non-hierarchical access control policies, in addition to those in a strict hierarchy. An interesting application is also given in this paper to show the importance of non-hierarchical access control. Key-Words: Key assignment, Multilevel security, Access control, Cryptogr...

The basic motivation of multilevel database systems is to share data from different security levels. However, current models have to rapidly store some information in different security levels to protect signal channel. Leakages could also occur when current models deal with the null values. In this research we propose a novel security model, the instance-based multilevel security model to solv...

A multilevel database is intended to provide the security needed for database systems that contain data at a variety of classifications and serve a set of users having different clearances. This paper describes a formal security model for a such a system. The model is formulated in two layers, one corresponding to a reference monitor that enforces mandatory security, and the second an extension...

Mandatory label-based policies may be used to support a wide-range of application security requirements. Labels encode the security state of system entities and the security policy speciies how these labels may change. Building on previous results, this paper develops a model for a kernelized framework for supporting these policies. The framework provides the basis for, what is essentially, an ...

This paper describes a logic we call Nonmonotonic Typed Multilevel Logic (NTML) for multilevel database applications. It also describes various approaches to viewing multilevel databases through NTML and discusses techniques for query evaluation and integrity checking.