Efficient access enforcement in distributed role-based access control (RBAC) deployments

We address the distributed setting for enforcement of a centralized Role-Based Access Control (RBAC) protection state. We present a new approach for time- and space-efficient access enforcement. Underlying our approach is a data structure that we call a cas-cade Bloom filter. We describe our approach, provide details about the cascade Bloom filter, its associated algorithms, soundness and completeness properties for those algorithms, and provide an em-pirical validation for distributed access enforcement of RBAC. We demonstrate that even in low-capability devices such as WiFi net-work access points, we can perform thousands of access checks in a second

A theory based on security analysis for comparing the expressive power of access control models

We present a theory for comparing the expressive power of access control models. Our theory is based on reductions that preserve the results of security analysis. Security analysis is an approach to the verification of security policies in access control systems. We demonstrate the effectiveness of the theory by applying it in several cases. Also, we present related results on safety analysis in Discretionary Access Control (DAC) and security analysis in Role-Based Access Control (RBAC)

COMPARING THE EXPRESSIVE POWER OF ACCESS CONTROL MODELS

Comparing the expressive power of access control models is recognized as a fundamental problem in computer security. Such comparisons are generally based on simulations between different access control schemes. However, the definitions for simulations that are used in the literature make it impossible to put results and claims about the expressive power of access control models into a single context. Furthermore, some definitions for simulations used in the literature such as those used for comparing RBAC (Role-Based Access Control) with other models, are too weak to distinguish access control models from one another in a meaningful way. We propose a theory for comparing the expressive power of access control models. We perceive access control systems as state-transition systems and require simulations to preserve security properties. We discuss the rationale behind such a theory, apply the theory to reexamine some existing work on the expressive power of access control models in the literature and present three results. We show that: (1) RBAC with a particular administrative model from the literature (ARBAC97) is limited in its expressive power; (2) ATAM (Augmented Typed Access Matrix) is more expressive than TAM (Typed Access Matrix), thereby solving an open problem posed in the literature; and (3) a trust-management language is at least as expressive as RBAC with a particular administrative model (the URA97 component of ARBAC97)

SECURITY ANALYSIS IN ROLE-BASED ACCESS CONTROL

The administration of large Role-Based Access Control (RBAC) systems is a challenging problem. In order to administer such systems, decentralization of administration tasks by the use of delegation is an effective approach. While the use of delegation greatly enhances flexibility and scalability, it may reduce the control that an organization has over its resources, thereby diminishing a major advantage RBAC has over Discretionary Access Control (DAC). We propose to use security analysis techniques to maintain desirable security properties while delegating administrative privileges. We give a precise definition of a family of security analysis problems in RBAC, which is more general than safety analysis that is studied in the literature. We show that two classes of problems in the family can be reduced to similar analysis in the RT[և, ∩] role-based trust-management language, thereby establishing an interesting relationship between RBAC and the RT framework. The reduction gives efficient algorithms for answering most kinds of queries in these two classes and establishes the complexity bounds for the intractable cases

A Theory for Comparing the Expressive Power of Access Control Models

Comparing the expressive power of access control models is recognized as a fundamental problem in computer security. While such comparisons are generally based on simulations between different access control schemes, the definitions for simulations that are used in the literature are informal, and make it impossible to put results and claims about the expressive power of access control models into a single context. Furthermore, some definitions for simulations used in the literature such as those used for comparing RBAC (Role-Based Access Control) with other models, are too weak to distinguish access control models from one another in a meaningful way. We propose a theory for comparing the expressive power of access control models. We perceive access control systems as state-transition systems and require simulations to preserve security properties. We discuss the rationale behind such a theory, apply the theory to reexamine some existing work on the expressive power of access control models in the literature, and present four results. We show that: (1) the well known HRU scheme is limited in its expressive power when compared to a rather simple trust-management scheme, thereby formally establishing a conjecture from the literature; (2) RBAC with a particular administrative scheme from the literature (ARBAC97) is limited in its expressive power, countering claims in the literature that RBAC is more expressive than DAC (Discretionary Access Control) schemes; (3) the ability to check for the absence of rights (in addition to the presence of rights) causes ATAM (Augmented Typed Access Matrix) to be more expressive than TAM (Typed Access Matrix); and (4) a trust-management scheme is at least as expressive as RBAC with a particular administrative scheme (the URA97 component of ARBAC97)