## 4 Related Work  
[PERSON] explains that scalability poses a significant challenge when it comes to improving the access management of IoT systems based on blockchain technology [18]. The study focuses on maximizing scalability by employing various access-managementconfigurations. The researchers emphasize that blockchain-based IoT systems have limited access-management capabilities due to resource sharing and permission restrictions [18]. The study introduces a flexible access management system based on blockchain technology, which operates on a decentralized digital ledger. According to the authors, this system offers several benefits, including isolated managerial domains, access control policies, and continuous administrative functions [18]. Additionally, this paper highlights that the proposed system is energy-efficient and cost-effective compared to other commercially available access management systems. The authors also implement a cross-platform communication system to validate interactions among IoT devices [18]. The paper concludes that utilizing blockchain access management configurations is a viable approach to enhancing scalability capabilities and performance capacities. To develop the blockchain-based access management system, the authors adopt the CoAP management interface developed by the Internet Engineering Task Force (IETF) [18]. As stated by [PERSON] et al., the main objective of IoT-based smart home automation systems is to enhance and simplify people's lives [19]. These systems utilize a variety of smart consumer products and sensors to provide convenience. The authors explain that the IoT industry incorporates automated electrical appliances, wearable electronics, and tracking devices across various sectors such as agriculture, healthcare, and energy [19]. However, due to their limited processing capacity, IoT devices are susceptible to security attacks. The authors have identified four major categories of IoT-related attacks, namely physical attacks, network attacks, software attacks, and data attacks [19]. To address these security concerns, the authors suggest that blockchain technology can serve as a robust solution. Blockchain has the potential to mitigate security issues like unauthorized access, privacy breaches, data tampering, and malicious actions [19]. Additionally, the authors highlight the advantages of blockchain technology in enhancing industrial productivity and efficiency within the manufacturing sector. They also propose that smart contracts can offer a secure environment for processing data and ensuring data integrity [19]. According to [PERSON], cybersecurity threats to IoT technologies arise from issues such as poor compatibility, limited processing power, and insecure data transmissions [20]. [PERSON] and the other authors of the study investigated the potential use of blockchain technology in IoT systems and put forth a novel architecture called Blockchain of Things (BCoT) [20]. They also examined the applicability of blockchain technology in conjunction with 5G cellular connections. The authors assert that the utilization of IoT cyber-physical systems presents challenges due to the wide array of devices and systems, complex networks, diverse IoT data, and resource limitations [20]. However, they also highlight the opportunities that blockchain technology can offer in addressing these challenges. The paper underscores the capability of blockchain technology to validate IoT data and establish a mutually trusted cyber system based on blockchain [20]. The authors introduce four key metrics for BCoT: interoperability, traceability, reliability, and autonomic interactions. Interoperability refers to the seamless exchange of information between IoT systems, while traceability pertains to the ability to track data blocks [20]. Reliability encompasses the quality of network services and IoT data availability. Autonomic interactions involve the ability to engage with trusted IoT systems. As emphasized by the authors, BCoT can be a potential solution for untrusted IoT networks [20].