## 3 Hyperledger Fabric
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Reference** & **Type of Security** & **Key Characteristics** \\ \hline
[20] & Authentication mechanism & Decentralization, simplicity, general application \\ \hline
[25] & Attribute-based access control (ABAC) mechanism for IoT devices & Development of ABAC mechanism, access control system design and policies, rules for network and channel settings, signature and Implicit Meta policies, resource access control lists (ACLs) \\ \hline
[24] & Authentication and Authorization model & Securing edge computing devices, traceability of IoT data, scalability, smart-contract queries \\ \hline
[29] & Lightweight group management (H-LGM) model & Group management for IoT devices, lightweight rekeying, group key (GK) utilization, agent-based rekeying \\ \hline
[26] & Blockchain-based access control system for IoT &
\begin{tabular}{c} Dynamic access control management, record tracing, \\ Attribute-Based Access Control (ABAC) model, secure sharing \\ of data resources, simplified sharing mode and storage \\ structure, device access control policy based on ABAC \\ \end{tabular} \\ \hline
[27] & Access control system for Industrial Internet of Things (IIoT) &
\begin{tabular}{c} Decentralized, fine-grained, and dynamic access control management, attribute-based access control (ABAC), three smart contracts for policy management, resource URL storage, and access control \\ \end{tabular} \\ \hline
[21] & Distributed identity-based authentication scheme &
\begin{tabular}{c} Distributed PKG, elimination of single point of failure and key \\ escrow problem, security protocol for IoT device authentication \\ using IBE \\ \end{tabular} \\ \hline
[22] & Distributed authentication infrastructure &
\begin{tabular}{c} Distribution of trust points, cross-certification, decentralized \\ trust model (Meta-PKI) \\ \end{tabular} \\ \hline
[30] & Privacy protection scheme with ring signature and aggregated signature &
\begin{tabular}{c} Identity privacy protection, prevention of identity leakage, ring \\ signature method, aggregated signature method, accountability \\ mechanism, three-role scheme architecture \\ \end{tabular} \\ \hline
[23] & Decentralized authorization model with multiple ASs and two blockchains &
\begin{tabular}{c} Multiple authorization servers (ASs), two blockchains for \\ authorization and payments, interledger mechanisms, OAuth \\ 2.0 delegated authorization framework, CBOR Web Token \\ (CWT) format \\ \end{tabular} \\ \hline
[28] & Attribute-Based Access Control Model for IoT &
\begin{tabular}{c} Fine-grained and expressive access control, attribute-based \\ permission management \\ \end{tabular} \\ \hline
[31] & Decentralized data integrity auditing scheme &
\begin{tabular}{c} Utilization of separate communication channels for \\ User-TPA-CSP, mitigating risks of privacy breaches \\ \end{tabular} \\ \hline
[32] & Secure data transfer scheme &
\begin{tabular}{c} Utilization of IPFS for encrypted storage, design of \\ Keyword-index, use of Chaincode and ECDSA for data \\ integrity and mutual authentication \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 1: HF-based mechanisms and schemes for IoT. use cases and trust models. For instance, fully byzantine fault-tolerant consensus may be deemed redundant and an undue drag on performance and throughput when it is deployed within a single business or when it is controlled by a trusted authority. In circumstances such as these, a consensus protocol that is crash fault-tolerant (CFT) may be more than sufficient; however, in a multi-party, decentralized use case, a consensus protocol that is byzantine fault-tolerant (BFT) may be necessary [36]. For all these reasons, HF can be a viable blockchain platform to develop upon lightweight blockchain-based security solutions for IoMT networks [15; 37]. In HF, the workflow from the initiation of a transaction to the update of the ledger involves several stages, as shown in Figure 1. As a first step, a transaction is initiated by a client.