The existence of errors or inconsistencies in the configuration of security components, such as filtering routers and or firewalls, may lead to weak access control policies -- potentially easy to be evaded by unauthorized parties. We present in this paper a proposal to create, manage, and deploy consistent policies in those components in an efficient way. To do so, we combine two main approaches. The first approach is the use of an aggregation mechanism that yields consistent configurations or signals inconsistencies. Through this mechanism we can fold existing policies of a given system and create a consistent and global set of access control rules -- easy to maintain and manage by using a single syntax. The second approach is the use of a refinement mechanism that guarantees the proper deployment of such a global set of rules into the system, yet free of inconsistencies.
However, their work does not fix, from our point of view, clear semantics, and their concept of role becomes ambiguous as we pointed out in @cite_10 . Another work based on policy refinement is the RBNS model @cite_16 . However, and although the authors claim that their work is based on the RBAC model @cite_13 , it seems that they only keep from this model only the concept of role. Indeed, the specification of network entities and role and permission assignments are not rigorous and does not fit any reality @cite_10 .
@cite_13 @cite_16 @cite_10
2144565093 2115403742 1986989788 1967221886
Several models for incorporating spatial constraints into role-based access control (RBAC) have been proposed, and researchers are now focusing on the challenge of ensuring such policies are enforced correctly. However, existing approaches have a major shortcoming, as they assume the server is trustworthy and require complete disclosure of sensitive location information by the user. In this work, we propose a novel framework and a set of protocols to solve this problem. Specifically, in our scheme, a user provides a service provider with role and location tokens along with a request. The service provider consults with a role authority and a location authority to verify the tokens and evaluate the policy. However, none of the servers learn the requesting user's identity, role, or location. In this paper, we define the protocols and the policy enforcement scheme, and present a formal proof of a number of security properties. In this paper we present a context-aware RBAC (CARBAC) model for pervasive computing applications. The design of this model has been guided by the context-based access control requirements of such applications. These requirements are related to users' memberships in roles, permission executions by role members, and context-based dynamic integration of services in the environment with an application. Context information is used in role admission policies, in policies related to permission executions by role members, and in policies related to accessing of dynamically interfaced services by role members. The dynamic nature of context information requires model-level support for revocations of role memberships and permission activations when certain context conditions fail to hold. Based on this model we present a programming framework for building context-aware applications, providing mechanisms for specifying and enforcing context-based access control requirements. Role-Based Access Control (RBAC) is supported directly or in a closely related form, by a number of products. This article presents a formalization of RBAC using graph transformations that is a graphical specification technique based on a generalization of classical string grammars to nonlinear structures. The proposed formalization provides an intuitive description for the manipulation of graph structures as they occur in information systems access control and a precise specification of static and dynamic consistency conditions on graphs and graph transformations. The formalism captures the RBAC models published in the literature, and also allows a uniform treatment of user roles and administrative roles, and a detailed analysis of the decentralization of administrative roles. In this article, we present a comprehensive approach for privacy preserving access control based on the notion of purpose. In our model, purpose information associated with a given data element specifies the intended use of the data element. A key feature of our model is that it allows multiple purposes to be associated with each data element and also supports explicit prohibitions, thus allowing privacy officers to specify that some data should not be used for certain purposes. An important issue addressed in this article is the granularity of data labeling, i.e., the units of data with which purposes can be associated. We address this issue in the context of relational databases and propose four different labeling schemes, each providing a different granularity. We also propose an approach to represent purpose information, which results in low storage overhead, and we exploit query modification techniques to support access control based on purpose information. Another contribution of our work is that we address the problem of how to determine the purpose for which certain data are accessed by a given user. Our proposed solution relies on role-based access control (RBAC) models as well as the notion of conditional role which is based on the notions of role attribute and system attribute.