Computer Science and Engineering, Department of


First Advisor

Peter Revesz

Date of this Version



A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Computer Science, Under the Supervision of Professor Peter Revesz. Lincoln, Nebraska :December 2003

Copyright 2003 Scot Anderson


Constraint Datalog holds an increasing role in Trust Management. We discuss several Trust Management systems and give a description of the environment and requirements for Trust Management. Constraint Datalog using addition constraints and approximation theory provides an expressive semantic with which to describe security policies for credentials, delegations and authorizations. Approximation theory allows halting in Constraint Datalog over addition constraints. We use the decision problem of Diophantine equations to show that Constraint Datalog over addition constraints is complete. Combining these two concepts provides an approximately complete, safe language. The problem of constant additions to closed languages provides reasons for using an approximately complete, safe language for Trust Management. Semantics for the Role-based Trust Management framework (RT) are given in Constraint Datalog over addition constraints including an alternate form of a threshold policy.

Advisor: Peter Revesz