# A Survey on Emerging Blockchain Technology Platforms for Securing the Internet of Things
## 6 Conclusions  
The IoT security ecosystem has witnessed a great transformation with the introduction of blockchain, and several research projects have explored this technology. This paper reviewed works from the blockchain platform perspective. This was achieved through a review of literature by identifying the gaps and positioning the contributions. This paper is more security-centric compared to the existing literature. It presents a detailed review of the emerging blockchain platforms used in IoT system security, with more emphasis on cryptography and other security components of the blockchain. The reviewed work  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**S/N** & **Security Challenges** & **Research Works** & **Blockchain Technologies** \\ \hline \multirow{2}{*}{1.} & Weak Authentication and & \multirow{2}{*}{[40; 55; 75]} & Immutable Ledger, \\  & Uncontrolled Access & & Decentralised Identity, \\  & & & Digitally signed Wallet \\ \hline \multirow{2}{*}{2.} & Insecure Network Services & \multirow{2}{*}{[47]} & Encrypted Communication, \\  & and Communication & & Smart Contracts/ Chain-code. \\ \hline \multirow{2}{*}{3.} & Lack of Secure Update & \multirow{2}{*}{[53]} & Immutable Update History, \\  & Mechanism & & Decentralised Distribution \\ \hline \multirow{2}{*}{4.} & \multirow{2}{*}{Insufficient Privacy Protection} & \multirow{2}{*}{[42]} & Data Access Control, DBA, \\  & & & Auditable Data Provenance \\ \hline \multirow{2}{*}{5.} & \multirow{2}{*}{Data Protection} & \multirow{2}{*}{[49; 79]} & Blockchain Digital signature, \\  & & & Consensus Algorithm \\ \hline \hline \end{tabular}
\end{table}
Table 4: Breakdown of IoT security enhancement with BC-components.  
presented a greater adoption of private and hybrid blockchains compared to exclusively public blockchains, with 55%, 25%, and 20%, respectively, in the number of works. Technology such as IPFS, cloud technology, TSL, fog, etc. has been identified as promising for complementing security in IoT-Blockchain Integration. Also, there has been an increase in research work in this field in the last few years and we expect more to come.  
Potential directions in this domain include the following: Improving the existing consensus mechanism to enhance more adoption of it in the resource-constrained IoT system without compromising security, such as using Proof of Location (PoL). Cryptography: More work should be done to further discover lightweight cryptography algorithms that will be quantum-proof. Innovative identity mechanisms, e.g., decentralised identity, can be adopted in place of full blockchain nodes for very light IoT devices.  
Conceptualization, Y.K., D.D. and E.G.; methodology, Y.K. and D.D.; validation, D.D. and E.G.; formal analysis, Y.K., D.D. and E.G.; investigation, Y.K., D.D. and E.G.; resources, Y.K., D.D. and E.G.; data curation, Y.K. and D.D.; writing--original draft preparation, Y.K. and D.D.; writing--review and editing, Y.K., D.D. and E.G.; visualization, Y.K. and D.D.; supervision, D.D. and E.G.; project administration, D.D.; funding acquisition, D.D. All authors have read and agreed to the published version of the manuscript.  
This research was funded by Arab-German Young Academy (AGYA) Academy grant number 01 DL20003 from BMBF. This research was funded by UWE Bristol: PHD Scholarship from Computer Science Research Centre, College of Arts, Technology and Environment, +CHIST-ERA EU Project grant number EP/Y036301/1 from EPSRC.  
No new data were created or analyzed in this study.  
Sincere appreciation to the reviewers for their insightful comments.  
The authors declare no conflicts of interest.