Recently, several researchers motivated the need to integrate Zero Trust (ZT) principles when designing and implementing authentication and authorization systems for IoT. An integrated Zero Trust IoT system comprises the network infrastructure (physical and virtual) and operational policies in place for IoT as a product of a ZT architecture plan. This article proposes a novel Zero Trust architecture for IoT systems called ZTA-IoT. Additionally, based on different types of interactions between various layers and components in this architecture, we present ZTA-IoT-ACF, an access control framework that recognizes different interactions that need to be controlled in IoT systems. Within this framework, the article then refines its focus to object-level interactions, i.e., interactions where the target resource is a device (equivalently a thing) or an information file generated or stored by a device. Building on the recently proposed Zero Trust score-based authorization framework (ZT-SAF), we develop the object-level Zero Trust score-based authorization framework for IoT systems, denoted as ZTA-IoT-OL-SAF, to govern access requests in this context. With this machinery in place, we finally develop a novel usage control model for users-to-objects and devices-to-objects interactions, denoted as UCON \(_{IoT}\) . We give formal definitions, illustrative use cases, and a proof-of-concept implementation of UCON \(_{IoT}\) . This article is a first step toward establishing a rigorous formally defined score-based access control framework for Zero Trust IoT systems.

The internet of Things (IoT) refers to a network of physical objects that are equipped with sensors, software, and other technologies in order to communicate with other devices and systems over the internet. IoT has emerged as one of the most important technologies of this century over the past few years. To ensure IoT systems' sustainability and security over the long term, several researchers lately motivated the need to incorporate the recently proposed zero trust (ZT) cybersecurity paradigm when designing and implementing access control models for IoT systems. This poster proposes a hybrid access control approach incorporating traditional and deep learning-based authorization techniques toward score-based ZT authorization for IoT systems.

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$_{RC}$and HyBAC$_{AC}$, 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.

Zero trust (ZT) is the term for an evolving set of cybersecurity paradigms that move defenses from static, network-based perimeters to focus on users, assets, and resources. It assumes no implicit trust is granted to assets or user accounts based solely on their physical or network location. We have billions of devices in IoT ecosystems connected to enable smart environments, and these devices are scattered around different locations, sometimes multiple cities or even multiple countries. Moreover, the deployment of resource-constrained devices motivates the integration of IoT and cloud services. This adoption of a plethora of technologies expands the attack surface and positions the IoT ecosystem as a target for many potential security threats. This complexity has outstripped legacy perimeter-based security methods as there is no single, easily identified perimeter for different use cases in IoT. Hence, we believe that the need arises to incorporate ZT guiding principles in workflows, systems design, and operations that can be used to improve the security posture of IoT applications. This paper motivates the need to implement ZT principles when developing access control models for smart IoT systems. It first provides a structured mapping between the ZT basic tenets and the PEI framework when designing and implementing a ZT authorization system. It proposes the ZT authorization requirements framework (ZT-ARF), which provides a structured approach to authorization policy models in ZT systems. Moreover, it analyzes the requirements of access control models in IoT within the proposed ZT-ARF and presents the vision and need for a ZT score-based authorization framework (ZT-SAF) that is capable of maintaining the access control requirements for ZT IoT connected systems.

In this paper, we consider the Visibility Graph Recognition and Reconstruction problems in the context of terrains. Here, we are given a graph G with labeled vertices v₀, v₁, …, v_{n-1} such that the labeling corresponds with a Hamiltonian path H. G also may contain other edges. We are interested in determining if there is a terrain T with vertices p₀, p₁, …, p_{n-1} such that G is the visibility graph of T and the boundary of T corresponds with H. G is said to be persistent if and only if it satisfies the so-called X-property and Bar-property. It is known that every "pseudo-terrain" has a persistent visibility graph and that every persistent graph is the visibility graph for some pseudo-terrain. The connection is not as clear for (geometric) terrains. It is known that the visibility graph of any terrain T is persistent, but it has been unclear whether every persistent graph G has a terrain T such that G is the visibility graph of T. There actually have been several papers that claim this to be the case (although no formal proof has ever been published), and recent works made steps towards building a terrain reconstruction algorithm for any persistent graph. In this paper, we show that there exists a persistent graph G that is not the visibility graph for any terrain T. This means persistence is not enough by itself to characterize the visibility graphs of terrains, and implies that pseudo-terrains are not stretchable.