## 3 Results and Discussion  
In the context of this study on the issue of applying multi-criteria decision making methods to optimal consensus protocol selection for blockchain-based IoT networks, the following main stages of developing a conceptual model of the selection system can be identified (Figure 1). Stage 1. Formalization of the problem as a multi-criteria decision-making problem. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Sources** & **Protocols** & **IoT** & **MCDM** \\ \hline
[4] [PERSON] et al. (2021) & 130 & - & - \\
[5] [PERSON] et al. (2021) & 15 & - & - \\
[6] [PERSON] (2021) & 28 & - & - \\
[7] [PERSON] et al. (2019) & 20 & - & - \\
[8] [PERSON] et al. (2020) & 18 & - & - \\
[10] [PERSON] et al. (2022) & 58 & - & - \\
[12] [PERSON] et al. (2022) & 12 & + & - \\
[13] [PERSON] et al. (2022) & 28 & + & - \\
[14] [PERSON] et al. (2020) & 24 & + & - \\
[16] [PERSON] et al. (2020) & 1 & + & - \\
[19] [PERSON] et al. (2020) & 10 & - & - \\
[21] [PERSON] et al. (2022) & 18 & - & + \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparative table of the works devoted to consensus protocols in light of the IoT and application of MCDM methods. Notation: + considered, - not considered. Figure 1: System for optimal consensus protocol selection for blockchain-based IoT networks. The Internet of Things environment is characterized by its diversity, incorporating a broad range of hardware and software solutions that must meet strict requirements related to power consumption, storage, and computational capabilities. In addition, IoT devices operate in dynamic environments where sensors generate constant data, and they must function in ad hoc networks that involve going online and offline depending on their power requirements. As a result of their flexibility, IoT devices are widely used in various applications, such as smart cities, supply chains, and healthcare. Consensus mechanisms are a critical component of blockchain deployments, and their selection is particularly important in IoT-targeted blockchain deployments. However, all blockchains have trade-offs, and there is no perfect blockchain solution. Some are more resource-intensive, while others are faster or more centralized. To compare various blockchains, this paper establishes a set of requirements to better understand their usability and impact in IoT environments. These requirements include processor usage, security, decentralization, storage, and transactions per second (TPS). Processor usage is critical in determining how IoT devices will agree on the content and order of the blockchain. Security is a vital factor to consider, given that blockchain implementations may offer stronger security guarantees than traditional IoT networks with central points of failure. Decentralization is a choice that operates on a sliding scale and affects the speed and scalability of the network. Storage is a crucial consideration for security and decentralization aspects, as IoT devices do not have the capacity to store large amounts of blockchain data. Finally, transactions per second is another important trade-off, where a higher number of nodes participating in consensus could result in lower speed but higher decentralization, and a lower number of nodes could lead to increased transaction throughput and lower block times, which is generally desirable for IoT devices. When choosing a consensus protocol, requirements are first determined that take into account a specific use case. The choice of the blockchain consensus protocol is formalized as an MCDM task as follows [21]. Let \(A=\{A_{1},A_{2},...,A_{m}\}\), which is the set of alternatives (consensus protocols). Let \(C=\{C_{1},C_{2},...,C_{n}\}\), which is the set of criteria. Let \(W=\{w_{1},w_{2},...,w_{n}\}\), which is the set of the weights of corresponding criteria, such that \(w_{j}\in[0,1]\), \(\sum_{j=1}^{n}w_{j}=1\).