Ahmad Salehi Shahraki

May Alhajri, Carsten Rudolph, Ahmad Salehi Shahraki

Wearable fitness devices are widely used to track an individual's health and physical activities to improve the quality of health services. These devices sense a considerable amount of sensitive data processed by a centralized third party. While many researchers have thoroughly evaluated privacy issues surrounding wearable fitness trackers, no study has addressed privacy issues in trackers by giving control of the data to the user. Blockchain is an emerging technology with outstanding advantages in resolving consent management privacy concerns. As there are no fully transparent, legally compliant solutions for sharing personal fitness data, this study introduces an architecture for a human-centric, legally compliant, decentralized and dynamic consent system based on blockchain and smart contracts. Algorithms and sequence diagrams of the proposed system's activities show consent-related data flow among various agents, which are used later to prove the system's trustworthiness by formalizing the security requirements. The security properties of the proposed system were evaluated using the formal security modeling framework SeMF, which demonstrates the feasibility of the solution at an abstract level based on formal language theory. As a result, we have empirically proven that blockchain technology is suitable for mitigating the privacy issues of fitness providers by recording individuals' consent using blockchain and smart contracts.

Jithu Geevargheese Panicker, Ahmad Salehi S., Carsten Rudolph

Device-to-device (D2D) communication is one of the most recent advancements in wireless communication technology. It was introduced in cellular communication technology by the 3rd Generation Partnership Project (3GPP) to lay a foundation for the evolving 5G architecture. It has now emerged as a promising technology for proximate devices. It enables proximate devices to communicate directly without the involvement of a third party network infrastructure. Researchers are analysing various methods to facilitate the smooth integration of D2D communication technology into the existing network system architecture. This paper lists all the different possible modes of operation in D2D communication based on the varying use-case scenarios and highlights the security and privacy requirements for D2D communication. Some of the recent authentication proposals for D2D communication technology are further reviewed, and their security and privacy capabilities are analysed. Apart from authentication, we also reviewed some recent proposals of access control in D2D and highlighted the security issues addressed. We then identified the open issues that prevail in implementing D2D technology in a real-world scenario for future researchers, emphasising the existing authentication and access control techniques in D2D communication.

M Ridwanur Rahman, Ahmad Salehi Shahraki, Carsten Rudolph

Access control models have been developed to control authorized access to sensitive resources. This control of access is important as there is now a need for collaborative resource sharing between multiple organizations over open environments like the internet. Although there are multiple access control models that are being widely used, these models are providing access control within a closed environment i.e. within the organization using it. These models have restricted capabilities in providing access control in open environments. Attribute-Based Access Control (ABAC) has emerged as a powerful access control model to bring fine-grained authorization to organizations that possess sensitive data and resources and want to collaborate over open environments. In an ABAC system, access to resources that an organization possess can be controlled by applying policies on attributes of the users. These policies are conditions that need to be satisfied by the requester in order to gain access to the resource. In this paper, we provide an introduction to ABAC and by carrying forward the architecture of ABAC, we propose a Decentralized Policy Information Point (PIP) model. Our model proposes the decentralization of PIP, which is an entity of the ABAC model that allows the storage and query of user attributes and enforces fine-grained access control for controlling the access of sensitive resources over multiple domains. Our model makes use of the concept of a cryptographic primitive called Attribute-Based Signature (ABS) to keep the identities of the users involved, private. Our model can be used for collaborative resource sharing over the internet. The evaluation of our model is also discussed to reflect the application of the proposed decentralized PIP model.