Access control is the process of mediating every request to resources and data maintained by a system and determining whether the request should be granted or denied. The access control decision is enforced by a mechanism implementing regulations established by a security policy. Different access control policies can be applied, corresponding to different criteria for defining what should, and ...

XML access control policies involving updates may contain security flaws, here called inconsistencies, in which a forbidden operation may be simulated by performing a sequence of allowed operations. This paper investigates the problem of deciding whether a policy is consistent, and if not, how its inconsistencies can be repaired. We consider policies expressed in terms of annotated DTDs definin...

The Web 2.0, GRID applications and more recently semantic desktop applications are bringing the Web to a situation where more and more data and metadata are shared and made available to large user groups. Things are further complicated by the highly unpredictable and autonomous dynamics of data, users, permissions and access control rules. For this novel scenario, a new access control model, Re...

Autonomous policy domains often need to share resources to accomplish a common task. To do this they must negotiate a common access control policy to the shared resources. We use mathematical techniques from game theory to show that the outcome of such negotiations can often be predicted from the distribution of power among the participants, independent of the actual mechanics of negotiation. W...

Access control mechanisms protect critical resources of systems from unauthorized access. In a policy-based management approach, administrators define user privileges as rules that determine the conditions and the extent of users’ access rights. As rules become more complex, analytical skills are required to identify conflicts and interactions within the rules that comprise a system policy – es...

The stack-based access control mechanism plays a fundamental role in the security architecture of Java and Microsoft CLR (common language runtime). It is enforced at runtime by inspecting methods in the current call stack for granted permissions before the program performs safety-critical operations. Although stack inspection is well studied, there is relatively little work on automated generat...

The capture, deployment and enforcement of appropriate access control policies are crucial aspects of many modern software-based systems. Previously, there has been a significant amount of research undertaken with respect to the formal modelling and analysis of access control policies; however, only a limited proportion of this work has been concerned with dynamic policies. In this paper we exp...

When defining Access Control Policies for XML Databases administrators need to make sure that they are not inconsistent, this is, that it is not possible to perform a forbidden operation through a sequence of allowed operations. This problem has been studied before for policies defined using authorizations based in insert, delete, replace and replaceVal types to control updates in documents tha...

Security requirements of a software product need to receive attention throughout its development lifecycle. This paper proposes the required notation and format to represent security requirements, especially access control policies in use case diagram and use case description. Such enhancements offer simple representation for positive and negative authorization, grouping sensitive use cases tha...

An extension of the λ-calculus is proposed, to study historybased access control. It allows for security policies with a possibly nested, local scope. We define a type and effect system that, given a program, extracts a history expression, i.e. a correct approximation to the set of histories obtainable at run-time. Validity of history expressions is non-regular, because the scope of policies ca...