## 4 Related Work
As per the authors, this approach guarantees the security of community interactions while dealing with potential inter-community attacks [24]. The test results are stored in the local blockchain. Also, the authors expect to address the security goals of confidentiality, integrity, and availability concerns by this new approach [24]. In the study conducted by [PERSON] et al., it was emphasized that as cyber-attacks and cybercrimes continue to evolve, it is crucial to ensure the security of digital health systems and have a mechanism in place to identify abnormal behaviours within these systems [25]. The authors propose that a permissioned blockchain architecture can effectively safeguard electronic health systems, providing reliability and accountability. Additionally, modern blockchain applications are designed to detect anomalous behaviours in blockchain networks, making it feasible to utilize blockchain technology in sensor networks to enhance data integrity and accountability [25]. This can be achieved through the implementation of an integrity-protection service model, which aims to ensure transparency in blockchain transactions within a permissioned network. By implementing this model in a sensor network, both security and performance aspects can be assessed [25]. According to [PERSON] et al., medical data security and the secure transmission of health information have become vital components of analysing medical big data [26]. As per the authors, the development of IoT technologies has led to the advancement of medical big data mining and analysis. These technologies utilize health sensors based on IoT to gather patient data for analysis. The authors have mentioned that health sensors are interconnected through the internet, forming IoT-based health sensor networks [26]. However, sensitive health information and health systems remain targets for cyber threats. The occurrence of cyber-attacks poses challenges to data integrity and accountability. To address this issue, blockchain technology has been proposed as a potential solution for protecting sensitive information against cyber-attacks by the authors [26]. The utilization of blockchain technology helps to mitigate privacy and confidentiality risks, as all block data transactions are safeguarded using encryption algorithms [26]. The purpose of the literature review is to show that there is a gap in the literature that this paper fills, as only a limited number of research papers have been published regarding scalability. Also, there has been very little research conducted to evaluate blockchain scalability using real test systems. Most existing related works have missed the importance of scalability that may occur in real blockchain systems. To bridge this gap, we have developed a blockchain-based sensor network to evaluate the scalability concerns. Our test results show the blockchain network parameters, including the blockchain architecture and number of users, can impact the scalability factor of blockchain networks. Our approach is based on experiments using real systems that can be used as a reference to develop similar blockchain-based sensor networks that consider scalability issues. Although researchers have identified blockchain as a potential security solution for IoT sensor networks, most existing blockchain applications are incompatible with commercially available IoT low-powered devices. We consider this a critical concern in this research paper, and our study shows that every blockchain application is not a possible solution for IoT low-powered devices. We discuss the research methodology and test bed development of the blockchain network prototype in the next section.