Correction: A scaling distributed access control model for blockchain-based file storage systems

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.

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.

Access control systems allow organizations to control user access to their resources with high reliability and availability. Blockchain technology can help in this case. However, when it comes to storing access control data, especially the matrix that defines user rights to files (DAC model) may be too large to be handled by blockchain as is. Thus, a decentralized access control model that results in a small amount of data storage on the blockchain can be beneficial in terms of the reliability of blockchain networks while allowing it to scale by adding large numbers of users and files. We present access control DAC model which uses a Merkle tree to store data, minimizes the storage size on the blockchain. This solution can be used with a variety of file storage systems, regardless of the used file storage technology. The proposed approach suggests additionally caching some requests to increase scaling. The proposed model was tested on 500 objects in a distributed environment.

Access control is an important component in the security of communication systems. While cryptography has rightfully been a significant component in the design of large scale communication systems, its relation to access control, especially its complementarity, has not often been brought out in full. With the wide availability of SELinux, a comprehensive model of access control has all the more become important. In many large scale systems, access control and trust management have become important components in the design. In survivable systems, models of group communication systems may have to be integrated with access control models. In this paper, we discuss the problem of integrating various formalisms often encountered in large scale communication systems, especially in connection with dynamic access control policies as well as trust management.

Access control is an important part of security in software, such as business applications, since it determines the access of users to objects and operations and the constraints of this access. Business and access control models are expressed using different representations. In addition, access control rules are not generally defined explicitly from access control models. Even though the business model and access control model are two separate modeling abstractions, they are inter-connected as access control is part of any business model. Therefore, the first goal is to add access control models to business models using the same fundamental building blocks. The second goal is to use these models and define general access control rules explicitly from these models so that the connection between models and their realizations are also present. This paper describes a new common representation for business models and classes of access control models based on the Resource---Event---Agent (REA) modeling approach to business models. In addition, the connection between models and their represented rules is clearly defined. We present a uniform approach to business and access control models. First, access control primitives are mapped onto REA-based access control patterns. Then, REA-based access control patterns are combined to define access control models. Based on these models, general access control rules are expressed in Extended Backus---Naur Form.

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.

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.

The EHR systems consist of very sensitive data originated by the interaction of the patients with the healthcare system. In order to control who can do what on the data in the system, it is necessary to use a security mechanism that is the access control (AC). In this paper, an innovative AC model is defined. It meets the main features that have to be satisfied by an EHR. Our proposal is an advanced access control model that combines access control models known in the literature. It adds the characteristics of modularity and easiness in the management of access policies, focusing attention on patient’s privacy and consent (patient privacy centric). The proposed model presents the following characteristics: attribute-based, multi-level, modular and with a dynamic and temporal management of the users’ lists. Besides, we have defined support functionalities that allow patients, organisations and physicians to take advantage of the AC potential.

In this paper, we review the important theoretical models of computer access control systems. Using the IBM Multiple Virtual Storage (MVS) operating system as the example, we show how the principles expressed in these models can be implemented. The roots of user authentication and access control on MVS are examined, tracing the convergence of the requirement for controls with the development of appropriate software. The paper also highlights security and auditing features unique to the host-centric computing model and discusses how these existing technologies might be applied to the security problems presented by the newer networking computing models. Finally, we look to the future and suggest the environment that will result when the host-centric computing model for security and access control is interoperated with the networking computing models.

Pervasive computing environments (PCE) derive the emergence of new pervasive application ranging from home to healthcare domain. These applications can be accessed from any place; at any time from anyone as in PCE users are mobile and may use mobile devices in accessing the resources and services. Thus controlling access to resource/services is a concern security question in PCE. Researchers have constructed many methods in order to restrict access in this environment such as context based access control (CBAC), trust based access control (TBAC) and recently many researchers have focused on enhance the role based access control (RBAC) model with other parameter/areas such as context information, business rule management, credential, neural network, trust and risk in order to come out with a new access control model that able to fit in PCE. This paper is to review the existing models that have extended RBAC model with those above mentioned areas.

On how to evaluate the performance of access control models, a method ofN-dimensional security entropy is described in this paper. According to the definition and description of the information entropy in information theory, the definition of the One-dimensional Security Entropy is introduced and the one-dimensional security entropy in Discretionary-access Control model is discussed firstly. Then theN-dimensional security entropy is extended based on the unauthorized access, and by means of theN-dimensional security entropy, the quantitative security performance is measured in RBAC model. In order to measure the security of management information system with complex role level, an extension of RBAC access control (EXRBAC) model is presented in this paper, which could get quantitative analysis withN-dimensional security entropy methods. Through analyzing and comparing the security performance of these three access control models, it is shown that the EXRBAC model performance is improved in multi-class and multi-level roles condition.

As a new computing mode, cloud computing can provide users with virtualized and scalable web services, which faced with serious security challenges, however. Access control is one of the most important measures to ensure the security of cloud computing. But applying traditional access control model into the Cloud directly could not solve the uncertainty and vulnerability caused by the open conditions of cloud computing. In cloud computing environment, only when the security and reliability of both interaction parties are ensured, data security can be effectively guaranteed during interactions between users and the Cloud. Therefore, building a mutual trust relationship between users and cloud platform is the key to implement new kinds of access control method in cloud computing environment. Combining with Trust Management(TM), a mutual trust based access control (MTBAC) model is proposed in this paper. MTBAC model take both user's behavior trust and cloud services node's credibility into consideration. Trust relationships between users and cloud service nodes are established by mutual trust mechanism. Security problems of access control are solved by implementing MTBAC model into cloud computing environment. Simulation experiments show that MTBAC model can guarantee the interaction between users and cloud service nodes.

Current access control mechanisms of the hospital information system can hardly identify the real access intention of system users. A relaxed access control increases the risk of compromise of patient privacy. To reduce unnecessary access of patient information by hospital staff, this paper proposes a knowledge-constrained role-based access control (KC-RBAC) model in which a variety of medical domain knowledge is considered in access control. Based on the proposed Purpose Tree and knowledge-involved algorithms, the model can dynamically define the boundary of access to the patient information according to the context, which helps to protect patient privacy by controlling access. Compared with the role-based access control model, KC-RBAC can effectively protect patient information according to the results of the experiments.

We propose the role-and-relation-based access control (R 2 BAC) model for workflow systems. In R 2 BAC, in addition to a user’s role memberships, the user’s relationships with other users help determine whether the user is allowed to perform a certain step in a workflow. For example, a constraint may require that two steps must not be performed by users who have a conflict of interest. We also study the workflow satisfiability problem, which asks whether a set of users can complete a workflow. We show that the problem is NP-complete for R 2 BAC, and is NP-complete for any workflow model that supports certain simple types of constraints (e.g., constraints that state certain two steps must be performed by two different users). After that, we apply tools from parameterized complexity theory to better understand the complexities of this problem. We show that the problem is fixed-parameter tractable when the only relations used are = and \(\ne\), and is fixed-parameter intractable when user-defined binary relations can be used. Finally, we study the resiliency problem in workflow systems, which asks whether a workflow can be completed even if a number of users may be absent. We formally define three levels of resiliency in workflow systems, namely, static resiliency, decremental resiliency and dynamic resiliency, and study computational problems related to these notions of resiliency.