Expressing Access Control Policies Research Articles

A revocable attribute-based access control system using blockchain

Attribute-based access control is an effective cryptographic mechanism that allows a data owner to perform attribute-level access control over users’ access capabilities. In the application background of blockchain, it is urgent to use attribute-based access control to solve a series of security problems. Although there exist several similar schemes, they do not consider attribute revocation. By adopting the attribute revocation technique based on binary trees, we extended Waters’ ciphertext policy attribute-based encryption (CP-ABE) scheme into a revocable CP-ABE (RCP-ABE) scheme. By combining our RCP-ABE with blockchain, we constructed a revocable attribute-based access control system. The new system supports expressive access control policies and allows the attribute authority to revoke users’ attributes or part of their attributes. The security analysis shows that the new system satisfies several ideal properties, i.e., forward security, backward security, confidentiality, and integrity.

Oblivious Transfer with Fine Grained Access Control from Ciphertext Policy Attribute Based Encryption in the Standard Model

In this work, an oblivious transfer with complex access control scheme that is constructed based on ciphertext policy attribute based encryption (CP-ABE) scheme is proposed. In this scheme, the database server can enforce fine grained access control for each record where the authorized user is allowed to access, but the unauthorized user cannot, whereas it learns neither which record a user accesses, nor which attributes a user has. This scheme has the advantages as follows: First, it allows the expressive access control policies where access structures are based on linear secret sharing scheme that directly supports AND, OR and Threshold gates. Second, the communication complexity in this scheme is constant in the numbers of records which have been accessed. Third, this scheme is constructed in prime order bilinear group. Fourth, this scheme is secure in the standard model. To the best of our knowledge, this scheme is the first to obtain these features simultaneously.

Extensible access control markup language integrated with Semantic Web technologies

The eXtensible Access Control Markup Language (XACML) is a standard language for expressing access control policies. The concept of authorization policy has been introduced in XACML-based Web security systems to reduce policy conflicts, enhance policy reusability, simplify policy analysis, and facilitate interoperability. Achieving these goals requires intelligent dynamic authorization. Unfortunately, conventional XACML lacks the computer interpretability needed to support knowledge representation. This study addresses the issue by defining a Multi-layer Semantic XACML Framework (MSACF) for integrating Semantic Web technologies in XACML. Based on the MSACF, this study also develops LAPAR, an intelligent XACML shell consisting of an Ontology Base, an XML-Based Repository, and an Inference Engine to enable different approaches for enhancing knowledge representations. The feasibility of LAPAR is confirmed in a prototype java-based implementation that can be associated with various domain ontologies and knowledge to enable dynamic authorization for different security applications.

Distributed access control policies for spectrum sharing

ABSTRACTCognitive radio is a novel wireless communication technology that allows for adaptive configuration of the reception parameters of a terminal, based on the information collected from the environment. Cognitive radio technology can be used in innovative spectrum management approaches such as spectrum sharing, where radio frequency spectral bands can be shared among various users through a dynamic exclusive‐use spectrum access model. Spectrum sharing can be applied to various scenarios in the commercial, public safety and military domain. In some scenarios, spectrum sharing demands a mechanism for expressing and enforcing access control policies for the allocation of resources including spectral bands. The access control polices should state what are the available resources (e.g., transmission/reception bandwidths), what are the users that are allowed to access them and under what conditions. However, because of the intrinsically highly dynamic nature of specific scenarios (e.g., public safety, military), where parties with various levels of authority may suddenly appear, it may be difficult to establish in advance what are the most suitable access control policies. Trust negotiation is a well‐known approach for expressing and enforcing distributed access control policies that depend on two or more parties. In this work, we present a trust negotiation‐based framework that allows for the definition of highly expressive and flexible distributed access control policies for the allocation of spectrum resources. Copyright © 2012 John Wiley & Sons, Ltd.

Policy analysis for Administrative Role-Based Access Control

Role-Based Access Control (RBAC) is a widely used model for expressing access control policies. In large organizations, the RBAC policy may be collectively managed by many administrators. Administrative RBAC (ARBAC) models express the authority of administrators, thereby specifying how an organization’s RBAC policy may change. Changes by one administrator may interact in unintended ways with changes by other administrators. Consequently, the effect of an ARBAC policy is hard to understand by simple inspection. In this paper, we consider the problem of analyzing ARBAC policies. Specifically, we consider reachability properties (e.g., whether a user can eventually be assigned to a role by a group of administrators), availability properties (e.g., whether a user cannot be removed from a role by a group of administrators), containment properties (e.g., every member of one role is also a member of another role) satisfied by a policy, and information flow properties. We show that reachability analysis for ARBAC is PSPACE-complete. We also give algorithms and complexity results for reachability and related analysis problems for several categories of ARBAC policies, defined by simple restrictions on the policy language. Some of these results are based on the connection we establish between security policy analysis and planning problems in Artificial Intelligence.

Encoding information flow in AURA (abstract only)

Two of the main ways to protect security-sensitive resources in computer systems are to enforce access-control policies and information-flow policies. In this paper, we show how to enforce information-flow policies in AURA, which is a programming language for access control. When augmented with this mechanism for enforcing information-flow polices, AURA can further improve the security of reference monitors that implement access control. We show how to encode security types and lattices of security labels using AURA's existing constructs for authorization logic. We prove a noninterference theorem for this encoding. We also investigate how to use expressive access-control policies specified in authorization logic as the policies for information declassification.

A Time and Mutable Attribute-Based Access Control Model

Access control is one of the most important technologies to guarantee computer security. A new model with support for valid time and usage constraint is described based on full analysis of flaws in existing models. In the new model, authorization rules can express access control policies completely and access constraints are necessary conditions to prevent authorization abuse. To solve the problems in implementation of the model, a sound scheme for administration of authorizations is proposed and some access decision algorithms are developed.

A general approach to securely querying XML

XML access control requires the enforcement of highly expressive access control policies to support schema-, document and object-specific protection requirements. Access control models for XML data can be classified in two major categories: node filtering and query rewriting systems. The first category includes approaches that use access policies to compute secure user views on XML data sets. User queries are then evaluated on those views. In the second category of approaches, authorization rules are used to transform user queries to be evaluated against the original XML data set. The pros and cons for these approaches have been widely discussed in the framework of XML access control standardization activities. The aim of this paper is to describe a model combining the advantages of these approaches and overcoming their limitations, suitable as the basis of a standard technique for XML access control enforcement. The model specification is given using a Finite State Automata, ensuring generality w.r.t. specific implementation techniques.