Biblio

Access control is a widely used technology to protect information security. The implementation of access control depends on the response generated by access control policies to users’ access requests. Therefore, ensuring the correctness of access control policies is an important step to ensure the smooth implementation of access control mechanisms. To solve this problem, this paper proposes a constraint based access control policy security analysis framework (CACPSAF) to perform security analysis on access control policies. The framework transforms the problem of security analysis of access control policy into the satisfiability of security principle constraints. The analysis and calculation of access control policy can be divided into formal transformation of access control policy, SMT coding of policy model, generation of security principle constraints, policy detection and evaluation. The security analysis of policies is divided into mandatory security principle constraints, optional security principle constraints and user-defined security principle constraints. The multi-dimensional security analysis of access control policies is realized and the semantic expression of policy analysis is stronger. Finally, the effectiveness of this framework is analyzed by performance evaluation, which proves that this framework can provide strong support for fine-grained security analysis of policies, and help to correctly model and conFigure policies during policy modeling, implementation and verification.

In the smart grid, the sharing of power data among various energy entities can make the data play a higher value. However, there may be unauthorized access while sharing data, which makes many entities unwilling to share their data to prevent data leakage. Based on blockchain and ABAC (Attribute-based Access Control) technology, this paper proposes an access control scheme, so that users can achieve fine-grained access control of their data when sharing them. The solution uses smart contract to achieve automated and reliable policy evaluation. IPFS (Interplanetary File System) is used for off-chain distributed storage to share the storage pressure of blockchain and guarantee the reliable storage of data. At the same time, all processes in the system are stored in the blockchain, ensuring the accountability of the system. Finally, the experiment proves the feasibility of the proposed scheme.

This work describes the architecture and prototype implementation of a novel trust-aware continuous authorization technology that targets consumer Internet of Things (IoT), e.g., Smart Home. Our approach extends previous authorization models in three complementary ways: (1) By incorporating trust-level evaluation formulae as conditions inside authorization rules and policies, while supporting the evaluation of such policies through the fusion of an Attribute-Based Access Control (ABAC) authorization policy engine with a Trust-Level-Evaluation-Engine (TLEE). (2) By introducing contextualized, continuous monitoring and re-evaluation of policies throughout the authorization life-cycle. That is, mutable attributes about subjects, resources and environment as well as trust levels that are continuously monitored while obtaining an authorization, throughout the duration of or after revoking an existing authorization. Whenever change is detected, the corresponding authorization rules, including both access control rules and trust level expressions, are re-evaluated.(3) By minimizing the computational and memory footprint and maximizing concurrency and modular evaluation to improve performance while preserving the continuity of monitoring. Finally we introduce an application of such model in Zero Trust Architecture (ZTA) for consumer IoT.

Many modern business models of the manufacturing industry use the possibilities of digitization. In particular, the idea of connecting machines to networks and communication infrastructure is gaining momentum. However, in addition to the considerable economic advantages, this development also brings decisive disadvantages. By connecting previously encapsulated industrial networks with untrustworthy external networks such as the Internet, machines and systems are suddenly exposed to the same threats as conventional IT systems. A key problem today is the typical network paradigm with static routers and switches that cannot meet the dynamic requirements of a modern industrial network. Current security solutions often only threat symptoms instead of tackling the cause. In this paper we will therefore analyze the weaknesses of current networks and security solutions using the example of industrial remote maintenance. We will then present a novel concept of how Software-Defined Networking (SDN) in combination with a policy framework that supports attribute-based access control can be used to meet current and future security requirements in dynamic industrial networks. Furthermore, we will introduce an examplary implementation of this novel security framework for the use case of industrial remote maintenance and evaluate the solution. Our results show that SDN in combination with an Attribute-based Access Control (ABAC) policy framework is perfectly suited to increase flexibility and security of modern industrial networks at the same time.

Attribute-Based Access Control (ABAC), a promising alternative to traditional models of access control, has gained significant attention in recent academic literature. This attention has lead to the creation of a number of ABAC models including our previous contribution, Hierarchical Group and Attribute-Based Access Control (HGABAC). However, to date few complete solutions exist that provide both an ABAC model and architecture that could be implemented in real life scenarios. This work aims to advance progress towards a complete ABAC solution by introducing Hierarchical Group Attribute Architecture (HGAA), an architecture to support HGABAC and close the gap between a model and real world implementation. In addition to HGAA we also present an attribute certificate specification that enables users to provide proof of attribute ownership in a pseudonymous and off-line manner, as well as an update to the Hierarchical Group Policy Language (HGPL) to support our namespace for uniquely identifying attributes across disparate security domains. Details of our HGAA implementation are given and a preliminary analysis of its performance is discussed as well as directions for future work.

The concept of Internet of Things (IoT) has received considerable attention and development in recent years. There have been significant studies on access control models for IoT in academia, while companies have already deployed several cloud-enabled IoT platforms. However, there is no consensus on a formal access control model for cloud-enabled IoT. The access-control oriented (ACO) architecture was recently proposed for cloud-enabled IoT, with virtual objects (VOs) and cloud services in the middle layers. Building upon ACO, operational and administrative access control models have been published for virtual object communication in cloud-enabled IoT illustrated by a use case of sensing speeding cars as a running example. In this paper, we study AWS IoT as a major commercial cloud-IoT platform and investigate its suitability for implementing the afore-mentioned academic models of ACO and VO communication control. While AWS IoT has a notion of digital shadows closely analogous to VOs, it lacks explicit capability for VO communication and thereby for VO communication control. Thus there is a significant mismatch between AWS IoT and these academic models. The principal contribution of this paper is to reconcile this mismatch by showing how to use the mechanisms of AWS IoT to effectively implement VO communication models. To this end, we develop an access control model for virtual objects (shadows) communication in AWS IoT called AWS-IoT-ACMVO. We develop a proof-of-concept implementation of the speeding cars use case in AWS IoT under guidance of this model, and provide selected performance measurements. We conclude with a discussion of possible alternate implementations of this use case in AWS IoT.

Attribute-based access control (ABAC) expresses authorization policy via attributes while relationship-based access control (ReBAC) does so via relationships. While ABAC concepts have been around for a long time, ReBAC is relatively recent emerging with its essential application in online social networks. Even as ABAC and ReBAC continue to evolve, there are conflicting claims in the literature regarding their comparison. It has been argued that ABAC can subsume ReBAC since attributes can encode relationships. Conversely there are claims that the multilevel (or indirect) relations of ReBAC bring fundamentally new capabilities. So far there is no rigorous comparative study of ABAC vis a vis ReBAC. This paper presents a comparative analysis of ABAC and ReBAC, and shows how various ReBAC features can be realized with different types of ABAC. We first identify several attribute types such as entity/non-entity and structured attributes that significantly influence ABAC or ReBAC expressiveness. We then develop a family of ReBAC models and a separate family of ABAC models based on the identified attribute types, with the goal of comparing the expressive power of these two model families. Further, we identify different dynamics of the models that are crucial for model comparison. We also consider different solutions for representing multilevel relationships with attributes. Finally, the ABAC and ReBAC model families are compared in terms of relative expressiveness and performance implications.

Authorization policy authoring has required tools from the start. With access policy governance now an executive-level responsibility, it is imperative that such a tool expose the policy to business users' with little or no IT intervention-as natural language. NIST SP 800-162 [1] first prescribes natural language policies (NLPs) as the preferred expression of policy and then implicitly calls for automated translation of NLP to machine-executable code. This paper therefore proposes an interoperable model for the NLP's human expression. It furthermore documents the research and development of a tool set for end-to-end authoring and translation. This R&D journey-focusing constantly on end users' has debunked certain myths, has responded to steadily increasing market sophistication, has applied formal disciplines (e.g. ontologies, grammars and compiler design) and has motivated an informal demonstration of autonomic code generation. The lessons learned should be of practical value to the entire ABAC community. The research in progress' increasingly complex policies, proactive rule analytics, and expanded NLP authoring language support will require collaboration with an ever-expanding technical community from industry and academia.

Fast Health Interoperability Services (FHIR) is the most recent in the line of standards for healthcare resources. FHIR represents different types of medical artifacts as resources and also provides recommendations for their authorized disclosure using web-based protocols including O-Auth and OpenId Connect and also defines security labels. In most cases, Role Based Access Control (RBAC) is used to secure access to FHIR resources. We provide an alternative approach based on Attribute Based Access Control (ABAC) that allows attributes of subjects and objects to take part in authorization decision. Our system allows various stakeholders to define policies governing the release of healthcare data. It also authenticates the end user requesting access. Our system acts as a middle-layer between the end-user and the FHIR server. Our system provides efficient release of individual and batch resources both during normal operations and also during emergencies. We also provide an implementation that demonstrates the feasibility of our approach.

The Internet of Things (IoT) is the latest evolution of the Internet, encompassing an enormous number of connected physical "things." The access-control oriented (ACO) architecture was recently proposed for cloud-enabled IoT, with virtual objects (VOs) and cloud services in the middle layers. A central aspect of ACO is to control communication among VOs. This paper develops operational and administrative access control models for this purpose, assuming topic-based publishsubscribe interaction among VOs. Operational models are developed using (i) access control lists for topics and capabilities for virtual objects and (ii) attribute-based access control, and it is argued that role-based access control is not suitable for this purpose. Administrative models for these two operational models are developed using (i) access control lists, (ii) role-based access control, and (iii) attribute-based access control. A use case illustrates the details of these access control models for VO communication, and their differences. An assessment of these models with respect to security and privacy preserving objectives of IoT is also provided.

The American National Standards Institute (ANSI) has standardized an access control approach, Next Generation Access Control (NGAC), that enables simultaneous instantiation of multiple access control policies. For large complex enterprises this is critical to limiting the authorized access of insiders. However, the specifications describe the required access control capabilities but not the related algorithms. While appropriate, this leave open the important question as to whether or not NGAC is scalable. Existing cubic reference implementations indicate that it does not. For example, the primary NGAC reference implementation took several minutes to simply display the set of files accessible to a user on a moderately sized system. To solve this problem we provide an efficient access control decision algorithm, reducing the overall complexity from cubic to linear. Our other major contribution is to provide a novel mechanism for administrators and users to review allowed access rights. We provide an interface that appears to be a simple file directory hierarchy but in reality is an automatically generated structure abstracted from the underlying access control graph that works with any set of simultaneously instantiated access control policies. Our work thus provides the first efficient implementation of NGAC while enabling user privilege review through a novel visualization approach. These capabilities help limit insider access to information (and thereby limit information leakage) by enabling the efficient simultaneous instantiation of multiple access control policies.

In recent years, Attribute Based Access Control (ABAC) has evolved as the preferred logical access control methodology in the Department of Defense and Intelligence Community, as well as many other agencies across the federal government. Gartner recently predicted that “by 2020, 70% of enterprises will use attribute-based access control (ABAC) as the dominant mechanism to protect critical assets, up from less that 5% today.” A definition and introduction to ABAC can be found in NIST Special Publication 800-162, Guide to Attribute Based Access Control (ABAC) Definition and Considerations and Intelligence Community Policy Guidance (ICPG) 500.2, Attribute-Based Authorization and Access Management. Within ABAC, attributes are used to make critical access control decisions, yet standards for attribute assurance have just started to be researched and documented. This presentation outlines factors influencing attributes that an authoritative body must address when standardizing attribute assurance and proposes some notional implementation suggestions for consideration. Attribute Assurance brings a level of confidence to attributes that is similar to levels of assurance for authentication (e.g., guidelines specified in NIST SP 800-63 and OMB M-04-04). There are three principal areas of interest when considering factors related to Attribute Assurance. Accuracy establishes the policy and technical underpinnings for semantically and syntactically correct descriptions of Subjects, Objects, or Environmental conditions. Interoperability considers different standards and protocols used for secure sharing of attributes between systems in order to avoid compromising the integrity and confidentiality of the attributes or exposing vulnerabilities in provider or relying systems or entities. Availability ensures that the update and retrieval of attributes satisfy the application to which the ABAC system is applied. In addition, the security and backup capability of attribute repositories need to be considered. Similar to a Level of Assurance (LOA), a Level of Attribute Assurance (LOAA) assures a relying party that the attribute value received from an Attribute Provider (AP) is accurately associated with the subject, resource, or environmental condition to which it applies. An Attribute Provider (AP) is any person or system that provides subject, object (or resource), or environmental attributes to relying parties regardless of transmission method. The AP may be the original, authoritative source (e.g., an Applicant). The AP may also receive information from an authoritative source for repacking or store-and-forward (e.g., an employee database) to relying parties or they may derive the attributes from formulas (e.g., a credit score). Regardless of the source of the AP's attributes, the same standards should apply to determining the LOAA. As ABAC is implemented throughout government, attribute assurance will be a critical, limiting factor in its acceptance. With this presentation, we hope to encourage dialog between attribute relying parties, attribute providers, and federal agencies that will be defining standards for ABAC in the immediate future.