Rewrite Specifications of Access Control Policies in Distributed Environments

Abstract

Abstract. We define a metamodel for access control that takes into account the requirements of distributed environments, where resources and access control policies may be distributed across several sites. This distributed metamodel is an extension of the category-based metamodel proposed in previous work (from which standard centralised access control models such as MAC, DAC, RBAC, Bell-Lapadula, etc. can be derived). We use a declarative formalism in order to give an operational semantics to the distributed metamodel. We then show how various distributed access control models can be derived as instances of the distributed metamodel, including distributed models where each site implements a different kind of local access control model.

A metamodel of access control for distributed environments: Applications and properties

“…This paper is based on preliminary work on rewrite-based specifications for the category-based metamodel presented in [19,20], and extends this previous work by providing new applications and new techniques for the analysis of policies obtained as instances of the metamodel.…”

“…Following [20], we first axiomatise a distributed access control metamodel, then give a rewrite-based operational semantics for this metamodel using the techniques introduced in [18], which allow us to deal in a uniform way with distributed systems where different access control policies are maintained locally. We demonstrate the expressive power of the distributed metamodel by showing how a distributed, dynamic, event-based access control model (the Distributed DEBAC model [18]) can be defined as an instance of the metamodel.…”

A graph-based framework for the analysis of access control policies

“…An axiomatisation of distributed category-based access control was proposed in [18] to specify federative policies as a composition of individual access control policies. In a federation, each member has its own access control policy, and contributes to the definition of a global access control policy.…”

“…Previous works on CBAC policies have used only textual languages and have focused mainly on the expressivity of the model, the analysis of policies and the techniques that can be used to enforce policies [9,17,18,19,1]. Graphbased languages have been used in the literature to model and analyse access control problems, but not within CBAC (with the exception of [3], which is the basis for this paper and considers CBAC policies without prohibitions).…”

Access Control and Obligations in the Category-Based Metamodel: A Rewrite-Based Semantics

“…There are other alternatives, e.g., considering undeterminate as answer if there is not enough information to grant the request. More generally, the relations BARCA and BAR were introduced in [6] to explicitly represent prohibitions, that is, to specify that an action is forbidden on a resource; UN DET was introduced to specify undeterminate answers. These relations obey the following axioms:…”