## 12 Conclusions, Limitations, and Future Work
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**S. No.**} & **Application Methodology** & **Description** & **Research Challenges** & **Reference** \\ \hline \multirow{6}{*}{06.} & \multirow{6}{*}{Smart Provenance} & Uses blockchain technology to prove the provenance of distributed data. Their paper suggested using blockchain technology to collect, verify, and manage data provenance. Additionally, smart contracts and open provenance models were studied to interpret the data trails. & A higher computation cost is associated with allocating each updated document, as it maintains the old memory for each document. Process identity is revealed through the use of a public address system. & \multirow{6}{*}{[57]} \\ \cline{3-3}  & & & A cloud-based blockchain for sharing knowledge about injection mould redesign in a secure manner. For private and blockchain technologies, cloud-based knowledge is recommended. The platform was redesigned to meet privacy and data format requirements. Similarly, the K-nearest neighbor algorithm was developed to retrieve information. & & \\ \hline \multirow{6}{*}{08.} & \multirow{6}{*}{B-RAN stands for blockchain Radio Access Network} & Using blockchain radio access (B-RANs), they developed decentralized, fast, and efficient methods to manage network access and authentication among inherently distrusting networks. & \multirow{6}{*}{[59]} \\ \cline{3-3}  & & Using blockchain to tamper-proof EHRs via the cloud. & Using cloud-based technology, they designed secure-health systems that eliminate illegal modifications. They analyzed communication overhead as as computational overhead with reduced computation time. & A blockchain is created by colluding between the data server and its corresponding transactions. In the absence of a central authority, multiple tokens need to be requested, which creates an environment of non-trust. & \\ \hline \multirow{6}{*}{09.} & \multirow{6}{*}{Census Bookkeeping using blockchain} & A cloud-network collaboration scenario can break the monopoly of Internet companies on network data by using blockchain token authorization and the right confirmation mechanism in the ledger, in conjunction with blockchain encryption, immutability, and traceability characteristics. It is confirmed that the data belongs to each user. A company that needs personal behavior data will use Token to process payments to individual users and provide credible authorization at the data layer to protect the legitimate interests of consumers. In this article, consensus accounting and blockchain technology are used when users purchase cloud services and network services to protect users’ privacy and avoid uploading their local data to cloud servers. Blockchain technology is also used to ensure transaction security in cloud-network collaborations. & \multirow{6}{*}{[61,62]} \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \hline \hline \end{tabular}  
* The article explains why DBFT consensus is superior to other consensus mechanisms for cloud-based collaboration with network delays, transmission errors, security holes, hacking, and malicious nodes, which are some of the major issues bookkeeping systems face using blockchain technology.  
\end{table} 
Table 4: _Cont._integrating cloud computing with blockchain technology. Based on the most current and relevant publications in the literature, we have conducted an extensive review of cloud computing. **Security services. ** The following are the results of the investigation as a whole, setting the stage by providing an overview of blockchain and cloud computing integration designs and models, as well as an explanation of the responsibilities played by clouds in the blockchain. Different blockchain security services in the cloud computing concept are being classified and discussed. We only look at how cloud computing may enhance the blockchain. The fourth part of the supplemental materials provides major cloud providers' current positions in merging cloud and blockchain.