Specification and Management of Attribute-based Authorization Policy

Oct 08, 2003

Abstract

An approach to authorization that is based on attributes of the resource requester provides flexibility and scalability that is essential in the context of large distributed systems. Logic programming provides an elegant, expressive, and well-understood framework in which to work with attribute-based authorization policy. This talk will summarize one specific attribute-based authorization framework built on logic programming: RT, a family of Role-based Trust-management languages. RT's logic programming foundation has facilitated the conception and specification of several extensions that greatly enhance its expressivity with respect to important security concepts such as parameterized roles, thresholds, and separation of duties. After examining language design issues, the talk will consider the problem of assessing authorization policies with respect to vulnerability of resource owners to a variety of security risks due to delegations to other principals, risks such as undesired authorizations and unavailability of critical resources. We will consider several such properties of RT policies, many of which we will see can be decided efficiently. For other properties, we will see that the complexity depends on the subset of RT in which the policy is expressed. The research is joint work with Professor Ninghui Li of Purdue University and Professor John C. Mitchell of Stanford University. The talk will conclude by discussing some prospects for continued research in this area.