Blockchain-Based Distributed Patient-Centric Image Management System
Round 1
Reviewer 1 Report
See attachment
Comments for author File: 
Comments.pdf
Author Response
We appreciate the reviewer taking the time to offer us valuable comments and useful insights to upgrade the paper. We have tried our best to address your constructive feedback. We hope that you will find these revisions meet your expectations. Please check the attached rebuttal report.
Author Response File: Author Response.pdf
Reviewer 2 Report
The paper proposes an image management system, which provides distributed immutable on-chain and off-chain storage enabling patient-centric management of images. The system is based on Ethereum blockchain and IPFS distributed file system.
The paper is well structured and well written. There are some general remarks/issues that should be taken into consideration before the paper could be accepted for publication.
The paper is missing the profound argumentation of why using public instead of consortium blockchain. Public type blockchain brings higher security while provoking higher costs (gas consumption, fees), delays in transaction processing, etc.
Another important issue lays in using IPFS. One of the most important benefits of IPFS is in the content propagation through the network – replicas. Robustness of the system is achieved through the replication. In the paper, it is mentioned that “the files can be accessed even if the host node is offline, as they are located in multiple locations for redundancy”. How many locations (nodes) hold the redundant copy? The propagation of the content in IPFS is made only if there is the interest of a particular node to hold the copy. It is totally different approach from the blockchain. So, if I am the only one interested in holding my images, then only my node will be hosting them. I believe that we understand what this means for the security of the system. Additionally, in the discussion section, it is mentioned that the proposed system is not allowing duplication of the content – so this is in contradiction to what IPFS stands for and what you mention earlier in the paper. The mentioned filecoin provisions financial recompensation for storing the content. But this means the replication of the content to reach higher propagation through the network, which you mention being a weakness of the MedChain project. So there are several contradictions considering the usage of IPFS. I believe this should be better explained to clear up doubts.
Another comment would be considering referring to blockchain technology in the introduction section. Bitcoin and Ethereum are mentioned as examples of blockchain technology. I would suggest being precise in this aspect – Bitcoin and Ethereum are applications of blockchain technology in the domain of cryptocurrencies. There are many other domains and many other applications. Often, talking about blockchain is related to Bitcoin or other cryptocurrencies. No doubt that blockchain technology reached its popularity due to the cryptocurrencies, but the technology is much more than just those applications. Therefore, I would suggest using more precise terminology.
Also when using the terminology of sharing data – the benefit here is in sharing access to data. We have efficient technologies for sharing data and for those purposes we would not need blockchain technology, but the huge benefit of the “novel technology” is in the shared access to data.
Author Response
We appreciate the reviewer taking the time to offer us valuable comments and useful insights to upgrade the paper. We have tried our best to address your constructive feedback. We hope that you will find these revisions meet your expectations.
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Authors adequately addressed my previous concerns. I believe that the manuscript is now ready for publication.
