RQ5: Does blockchain pose new security threats when implemented to safeguard the IoT applications?
| Name of the challenge | Description | References |
| Scalable data management issues | This is the only security threat found when implementing BC in IoT devices as the large amount of data generated by IoT devices presents the most significant barrier. The blockchain isn’t designed for a large amount of data as its implementation can only process a few transactions per second. Following that, there aren’t proper measures with an increase in the scale of blockchain with many heterogeneous devices. The heterogeneity can pose severe security such as malware injection. | Moin et al., 2019 |
| Data synchronization | It consumes a lot of time to identify and compute header to header information of large datasets of blockchain networks. | |
| Complexity | A blockchain network could be cumbersome and slow hence taking hours to process bitcoin logging transaction due to the decentralized complexities. | |
| Network speed | The blockchain technology neglects the physical aspects of networks and devices hence leading to slower generation speed of distribution over the whole IoT network. | Wang et al., 2019 |
| Energy wastage | The majority of popular blockchain technologies need to perform multiple computations to achieve consensus hence leading to energy wastage. | Sengupta et al., 2020 |
| Communication overhead | New transactions added to blockchain need to broadcast to all peers resulting in a lot of communication overhead. Additionally, all the peers need to synchronize and retain the copy blockchain further adding to the overhead. | |
| Efficiency | The verification algorithm runs on multiple times to the peers drastically reduces the operational efficiency. | |
| Storage capacity | The requirement of storing all transactions in one node introduces a problem of excessive system storage due to properties of distributed storage. | Yang et al., 2019 |
| Scalability | Many blockchains suffer from poor throughput which limits the extensive usage in large scale IoT | Dai et al., 2019 |
| Time latency | The validation of transaction in bitcoin blockchain takes around 10 minutes thus creating a problem for real-time applications | Kouicem et al., 2018 |
| Bandwidth consumption | It consumes a lot of bandwidth to validate many transactions generated by the IoT devices. |