## 1 Introduction
### Motivation  
The existing access control system only relies on identity-based, role-based, or attribute-based methods. Through analysis and comparison, it is observed that ABE is the optimal access control model among existing access models [7]. However, the public-key encryption does not fulfill the security requirements for attribute-based encryption. In our proposed approach, we use attribute-based signature (ABS) because it provides unforgettability and anonymity of the signer [8]. One of the main motivating problems of our proposed scheme is giving security to the subject, object, and personal health record (PHR) with both vital data confidentiality, and flexible fine-grained user anonymity access control without imposing an additional cost on them. We propose a novel data-sharing protocol by combining and exploiting two of the latest attribute-based cryptographic techniques to achieve our goals. They are attribute-based encryption (ABE) and attribute-based signature (ABS) with trust-based access control (TBAC) model using distributed ledger fabric [9]. Furthermore, we also provide a detailed comparison of our proposed scheme with several of the latest existing schemes. The development of urban areas environment, as well as and communication technology (ICT) industries, refer to the term \"smart city\". There is a global trend toward smart cities as global urbanization continues to expand, with the overall population anticipated to double by 2050 [10]. In order to accommodate the expanding population, cities require infrastructure and amenities to address transportation and environmental concerns. As a result, smart cities have emerged as a viable solution to the aforementioned issues. The rapid development of low-cost devices, including radio-frequency identification (RFID) devices, sensors, and actuators, are combined with the Internet of Things (IoT)-oriented infrastructure and wireless communication technology. For smart city applications, one of the major enabling technologies is the IoT that refers to the use of Internet technology to connect computer devices. In the Internet of Things, data is gathered via wireless networks and numerous physical sensors and analyzed in real time. The data gathered and analyzed is used to operate the actuators [11]. As a result, in the holistic development of IoT infrastructure in smart cities, critical factors, such as centralization, scalability, trust, privacy, and security, must be ensured. IoT systems, on the other hand, are heterogeneous and highly distributed in nature, and thus differ from traditional systems. Because of the unique characteristics of IoT, such as trust, privacy, IoT security maintenance, battery life, network bandwidth, processing capabilities, and memory capacity, the design of sustainable smart cities has proven problematic. However, the interconnectedness of numerous IoT sensors in smart networks creates a slew of potential aimed attacks. This research paper discusses the privacy issues associated with the use of consortium blockchain in IIoT environments. The reason for choosing Hyperledger Fabric blockchain is due to it being one of the most popular blockchain ecosystems utilized for implementing decentralized applications (Dapps). A report was carried out in mid-2020 by Coin Telegraph which shows that the number of Hyperledger Fabric accounts is around four times the number of Bitcoin addresses, highlighting its popularity among blockchain enthusiasts.There are various implementations of blockchain that utilize different frameworks and protocols based on the application they serve. These include, but are not limited to, the well-known Bitcoin [12] and Hyperledger [13]. There are multiple blockchain use-cases covering various industries, including healthcare [14], energy utilities, and government sector [15]. The significant difference between our proposed scheme and the traditional one is the application of the computational trust value.