Chapter 23 - Policies, Access Control, and Formal Methods

With the increasingly strict requirement for computer system security, access control models have become more complex. Existing models, such as discretionary access control (DAC) model, mandatory access control (MAC) model, role based access control (RBAC) model, and attribute based access control (ABAC) model, all have advantages and disadvantages regarding practicability and security. In addition, there is an inherent security risk in these access control models. The models merely control the access permission, but ignore the verification for the identity credibility of the entities involved in the access. With the proposal of trusted computing and the application of trusted platform, it is possible to implement, on stand-alone computers, the verification of identity credibility for the entities involved in the access. In this paper, we analyze the authorization and access decision policy of the RBAC model and the ABAC model. The characteristics of the trusted computing, which can ensure the identity credibility of the entities involved in the access, is also considered. Based on the above analysis, we establish a trusted computing based enhanced access control (TCBEAC) model, which can be deployed on stand-alone computers for common users.

Radio and television monitoring system is widely adopted by corporations such as transmission monitoring centers and transmitting stations in many provinces. The system is an important technical means to ensure the security of signal transmission and associated facilities. The use privilege management module, an important part of the monitoring system, has significance in protecting the security of transmission and transmitting system of radio and television. However, the problem is that dynamic execution environment constraint and device state constraint have not been considered in authentication and authorization process. In this paper, we introduce a new access control model based on rules constraint especially device status constraint. By establishing custom permission described statements, it can accurately describe fine-grained permission. The simple implementation of the authorization management module is given in the paper.

Combining the role-based access control (RBAC) model with the attribute-based access control (ABAC) model is a popular direction of current research on access control models. At present, many RABAC (RBAC + ABAC) models have been proposed. On the basis of RBAC model, these models dynamically apply ABAC rules to user-role mapping, role-permission mapping and user-permission mapping, thus realizing the usability and flexibility of access control models to some extent. But these models still have some insufficiencies in access control granularity and flexibility. This paper analyzes the defects of existing RABAC models and their causes, proposes a more fine-grained, flexible and efficient RABAC model, and realizes an access control system based on this model. Through the well-designed ABAC rules and their application modes, the system has achieved the goal of the RABAC model proposed by this paper and facilitated the administrator's management of access control rules.

Internet of Things (IoT) is revolutionizing and enhancing the quality of human lives in every aspect. With a disruption of IoT devices and applications, attackers are leveraging weak authentication and access control mechanisms on these IoT devices and applications to gain unauthorized access on user devices and data and cause them harm. Access control is a critical security mechanism to secure the IoT ecosystem which comprises cloud computing and edge computing services along with smart devices. Today major cloud and IoT service providers including Amazon Web Services (AWS), Google Cloud Platform (GCP), and Azure utilize some customized forms of Role-Based Access Control (RBAC) model along with specific authorization policies enabled by policy-based access control models. To enable fine-grained access control and overcome limitations of existing access control models, there is an imminent need to develop a flexible and dynamic access control model for securing smart devices, data and resources in the cloud-enabled IoT architecture. In this paper, we develop a formal attribute-based access control (ABAC) model for AWS IoT by building upon and extending previously developed access control model for AWS IoT, known as AWS-IoTAC model. We demonstrate the applicability of our proposed model through an industrial IoT use case and its implementation in the AWS IoT platform. Our proposed fine grained model for AWS IoT incorporates its existing capabilities and introduces new attributes for IoT entities and attribute-based policies for enabling expressive access control in AWS IoT. We also evaluate the performance of our model on the AWS cloud and IoT platform with the future smart industries use-case to depict the feasibility of our model in a real-world platform.

Access control is one of the techniques to provide accessibility, flexibility and control over the cloud resources. The traditional access control model is no longer sufficient to provide protection of data. Due to the rising data breaches, it is important to evolve our data security mechanisms. Therefore, it is better to combine several techniques to bring out the most efficient technique. Thus, this paper introduces custom access control model where Role- Based Access Control (RBAC) model and Attribute-Based Access Control (ABAC) model is combined to give a single hybrid model. This technique brings out the best qualities of both models. It provides both flexibility and dynamicity. The assignment of attributes provides better security. Key Words: Access Control, Role-Based Access Control, Attribute-Based Access Control, Cloud Computing

Smart homes are interconnected homes in which a wide variety of digital devices with limited resources communicate with multiple users and among themselves using multiple protocols. The deployment of resource-limited devices and the use of a wide range of technologies expand the attack surface and position the smart home as a target for many potential security threats. Access control is among the top security challenges in smart home IoT. Several access control models have been developed or adapted for IoT in general, with a few specifically designed for the smart home IoT domain. Most of these models are built on the role-based access control (RBAC) model or the attribute-based access control (ABAC) model. However, recently some researchers demonstrated that the need arises for a hybrid model combining ABAC and RBAC, thereby incorporating the benefits of both models to better meet IoT access control challenges in general and smart homes requirements in particular. In this paper, we used two approaches to develop two different hybrid models for smart home IoT. We followed a role-centric approach and an attribute-centric approach to develop HyBAC <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_{RC}$</tex-math></inline-formula> and HyBAC <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_{AC}$</tex-math></inline-formula> , respectively. We formally define these models and illustrate their features through a use case scenario demonstration. We further provide a proof-of-concept implementation for each model in Amazon Web Services (AWS) IoT platform. Finally, we conduct a theoretical comparison between the two models proposed in this paper in addition to the EGRBAC model (RBAC model for smart home IoT) and HABAC model (ABAC model for smart home IoT), which were previously developed to meet smart homes' challenges.

Internet of Things (IoT) brings not only wide range of opportunities but also security and privacy concerns. Consisting of many connected devices used in a highly interactive way, one of the main security concerns in IoT is unauthorized access. Traditional access control models do not support dynamic and fine-grained access control policies. Attribute-Based Access Control (ABAC) model is usually considered the most satisfactory access control model for running IoT applications. In this paper, we propose to take into the user authentication matching score obtained from a biometric authentication system consideration during making access control decisions. We emphasize the need of fine-grained access control and suggest to create access control policies per functionality of the device instead of per device regarding to the least privilege principle of information security. We give full or partial permission to certain functionalities of the IoT devices based on the user's authentication matching score thus provide more fine-grained and powerful access control mechanism. We present an extended Attribute-Based Access Control model that includes the assurance level of user authentication in access control policies and partially or fully permit the request accordingly.

A novel system for medical equipment supply chain traceability based on alliance chain and attribute and role access control

A Virtual Organization (VO) consists of some real organizations with common interests, which aims to provide inter organizational associations to reach some common goals by sharing their resources with each other. Providing security mechanisms, and especially a suitable access control mechanism, which enforces the defined security policy is a necessary requirement in VOs. Since VO is a complex environment with the huge number of users and resources, traditional access control models cannot satisfy VOs security requirements. Most of the current proposals are basically based on the attributes of users and resources. In this paper, we suggest using a combination of the semantic based access control (SBAC) model, and the attribute based access control (ABAC) model with the shared ontology of subjects' attributes in VOs. In this model, each participating organization makes its access control decisions according to an enhanced model of the ABAC model. However, access decision in the VO is made in more abstract level through an enhanced model of theSBACmodel. Using the ontology of users and resources in this model facilitates access control in large scale VOs with numerous organizations. By the combination ofSBACand ABAC, we attain their benefits and eliminate their shortcomings. In order to show the applicability of the proposed model, an access control system, based on the proposed model, has been implemented in Java using available APIs, including Sun's XACML API, Jena, Pellet, and Protege.

Collaborative environments need access control to data and resources to increase working cooperation efficiently yet effectively. Several approaches are proposed and multiple access control models are recommended in this domain. In this paper, four Role-Based Access Control (RBAC) based collaborative models are selected for analysis and comparison. The standard RBAC model, Team-based Access Control (TMAC) model, Privacy-aware Role-Based Access Control (P-RBAC) model and Dynamic Sharing and Privacy-aware RBAC (DySP-RBAC) model are used for experiments. A prototype is developed for each of these models and pros and cons of these models are discussed. Performance and sharing parameters are used to compare these collaborative models. The standard RBAC model is found better by having a quick response time for queries as compared to other RBAC models. The DySP-RBAC model outperforms other models by providing enhanced sharing capabilities.

The access control model is a core aspect of trusted information systems. Based on the role based access control (RBAC) model, we put forward the concept of thehomonymous role, which extends the role control categories in RBAC, balances the control granularity and the storage space requirements, and executes the fine‐grained access control. Instead of the traditional global access control policies (GACP), we propose thehomonymous control domain(HCD) mechanism to enable the coexistence of multiple types of access control policies in a single system, thereby improving the control granularity and flexibility. The HCD mechanism facilitates the discretionary supporting of independent access control policies for its homonymous user. The HCD mechanism and the traditional access control mechanism can be linked to construct a two‐layer access control policy mechanism for a system. Notably, we also consider the temporal characteristic in HCD, which is a critical feature of modern access control models. Furthermore, we analyze the conflicts between the HCD and GACP mechanisms. Finally, we design and implement our HCD on FreeBSD to demonstrate the advantages of the two‐layer access control mechanism. Copyright © 2008 John Wiley &amp; Sons, Ltd.

Delegation of access rights is becoming a common requirement of cloud based organizations. In this regard, various delegation models have been proposed. These models are strongly coupled with their specific access control model (ACM). For instance, if organization has deployed Role based Access Control (RBAC) model then it must use Role Based Delegation Model (RBDM). Similarly, Attribute Based Access Control (ABAC) model requires Attribute Based Delegation (ABDM) and so on. However, when organizations need to work in a collaborative environment, their heterogeneous environment in the context of ACMs, makes the delegation process difficult to achieve. To solve this issue, we have proposed a Generic Access Rights Delegation (GARD) framework for collaborative environment. We have considered group-centric Secure Information Sharing (g-SIS) model to develop a collaborative environment. Our framework generates a delegation policy as per underlying ACM of participating organization, dynamically. GARD provides interoperability between different ACMs during generation of delegation policies.

The rapid growth of Internet of Things (IoT)-enabled smart home environments has amplified the need for robust, scalable, and context-aware access control mechanisms. Traditional Role-Based Access Control (RBAC) and Attribute-Based Access Control (ABAC) models offer distinct advantages such as hierarchical simplicity and contextual granularity, respectively, yet exhibit critical limitations when deployed in isolation. To address these constraints, this study proposes and implements a discrete, hybrid RBAC–ABAC access control framework, engineered as a smart contract on the Binance Smart Chain (BSC), to ensure a secure, decentralized model for managing access to IoT resources. The framework leverages blockchain’s inherent strengths cryptographic integrity, immutable message digests, and tamper-resistant audit trails to reinforce data confidentiality and policy enforcement. Validated on a real-world testbed comprising ESP32-based IoT devices, a Raspberry Pi gateway, and a blockchain backend, the proposed system demonstrates enhanced resilience and trust. Quantitative evaluations benchmark the hybrid model against standalone RBAC and ABAC mechanisms across key metrics, including gas consumption, access latency, access decision accuracy, and scalability. The results indicate the hybrid model achieves superior accuracy (97.2%) and scalability (supporting 50 concurrent users and 30 devices), with moderate gas usage (15,000 gwei) and acceptable latency (1.8 seconds). Furthermore, the use of laser-secure transaction protocols and cryptographic primitives within the smart contract enhances the protection of access rights and resource interactions. This hybrid smart contract architecture not only bridges the gap between theoretical access control models and practical blockchain deployments but also sets a foundation for adaptive, secure, and decentralized policy enforcement in next-generation smart homes, particularly in resource-constrained environments.

The area of smart homes is one of the most popular for deploying smart connected devices. One of the most vulnerable aspects of smart homes is access control. Recent advances in IoT have led to several access control models being developed or adapted to IoT from other domains, with few specifically designed to meet the challenges of smart homes. Most of these models use role-based access control (RBAC) or attribute-based access control (ABAC) models. As of now, it is not clear what the advantages and disadvantages of ABAC over RBAC are in general, and in the context of smart-home IoT in particular. In this paper, we introduce HABACα, an attribute-based access control model for smart-home IoT. We formally define HABACα and demonstrate its features through two use-case scenarios and a proof-of-concept implementation. Furthermore, we present an analysis of HABACα as compared to the previously published EGRBAC (extended generalized role-based access control) model for smart-home IoT by first describing approaches for constructing HABACα specification from EGRBAC and vice versa in order to compare the theoretical expressiveness power of these models, and second, analyzing HABACα and EGRBAC models against standard criteria for access control models. Our findings suggest that a hybrid model that combines both HABACα and EGRBAC capabilities may be the most suitable for smart-home IoT, and probably more generally.

Wireless sensor networks (WSNs) have recently attracted much interest in the research community because of their wide range of applications. An emerging application for WSNs involves their use in healthcare where they are generally termed wireless medical sensor networks. In a hospital, outfitting every patient with tiny, wearable, wireless vital sign sensors would allow doctors, nurses, and other caregivers to continuously monitor the state of their patients. In such a scenario, patients are expected to be treated in reasonable time, so an access control model is needed, which will provide both real-time access to comprehensive medical records and detect unauthorized access to sensitive data. In emergency situations, a doctor or nurse needs to access data immediately. The loss in data availability can result in further decline in the patient's condition or can even lead to death. Therefore, the availability of data is more important than any security concern in emergency situations. To address that research issue for medical data in WSNs, we propose the break-the-glass access control (BTG-AC) model that is a modified and redesigned version of the break-the-glass role-based access control (BTG-RBAC) model to address data availability issue and to detect the security policy violations from both authorized and unauthorized users. Several changes within the access control engine are made in BTG-RBAC in order to make the new BTG-AC to apply and fit in WSNs. This paper presents the detailed design and development of the BTG-AC model based on a healthcare scenario. The evaluation results show that the concepts of BTG, prevention and detection mechanism, and obligation provide more flexible access than other current access control models in WSNs. Additionally, we compare the BTG-AC model with an adaptive access control (A2C) model, which has similar properties, for further evaluation. Alongside with the comparison, the advantages and disadvantages of BTG-AC over current WSN access control models are presented.