PONE-D-19-24458

Framework and algorithms for identifying honest blocks in blockchain

PLOS ONE

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He Debiao

Academic Editor

PLOS ONE

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Partly

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: N/A

Reviewer #2: I Don't Know

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3. Have the authors made all data underlying the findings in their manuscript fully available?

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Reviewer #1: Yes

Reviewer #2: No

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

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Reviewer #1: Yes

Reviewer #2: No

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: It is a very interesting article where authors had the objective presents a novel universal framework MaxCord based on graph theory for identifying the honest blocks in BlockDAG. The authors suggest that their study is pioneering and new research needs to be done to develop a better model for MaxCord. This article is well written, results are considerable.

Reviewer #2: This paper present a new algorithm to recognize honest blocks in the blockchain technology. This problem is timely with a great importance. Using the generalization of max independent set problem seems very interesting. The English needs improvement. The following are my comments and suggestions if the paper is selected for publication:

-The authors correctly identified the scalability and low transaction rate as key challenges of blockchain. However, it only applies to BitCoin blockchain with proof of work (PoW) mining methods and there exist a lot of other mining methods such as Proof of Stake (PoS), hybrid PoW/PoS, Proof of Importance (PoI), Delegated Proof of Stake (DPoS), PoL (Proof of Luck), and Stellar Consensus Protocol (SCP) to accelerate the block validation process that is not mentioned in the introduction.

-It seems to me that the BlockDAG is somewhat related to the Tangle structure that is considered to (or at least is claimed to) replace the blockchain structure in the next generation of blockchains to solve the scalability issue. For example, see the following reference. Please clarify on this matter.

Popov, Serguei. "The tangle." cit. on (2016): 131.

-Please clarify on the “honesty” concept in the early pages of the paper. Is it equivalent to tampered blocks with false information, or blocks that are mined by illegitimate miner? The reader should wait until section 2 to get what you mean.

-Please explain Equation (1). Why discord is finite when $d_{AB}^D$ is infinite and there is no common descendent for blocks A and B. I may miss a point here but it does not mean that B is not in the anticone of A?

-Please explain why the discord is smaller than $10$ for two honest blocks. First, why it is larger for dishonest blocks and secondly where the threshold 10 coming from. Does it depend on the size of networks, transaction rates, etc?

-My another question is that this screening mechanism applies to blocks after they join the graph and anticones are formed. Due to the random block selection methods, it may take a long time for a pair of two blocks to appear in each other’s anticone. Please clarify.

-The difference between the Maxcord-IFA and Maxcord-0Greedy is not clear to me.

-It would be useful to introduce the simulation Environment.

-The figures are barely readable. Perhaps adding some Tables would be helpful.

-The authors compared Maxcord family algorithms, but I encourage the authors to compare their method against other methods as well.

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Reviewer #1: No

Reviewer #2: Yes: Abolfazl Razi

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Framework and algorithms for identifying honest blocks in blockchain

PONE-D-19-24458R1

Dear Dr. Wu,

We are pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it complies with all outstanding technical requirements.

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With kind regards,

He Debiao

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #2: All comments have been addressed

Reviewer #3: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #2: Yes

Reviewer #3: Yes

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #2: Yes

Reviewer #3: Yes

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4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #2: Yes

Reviewer #3: Yes

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #2: No

Reviewer #3: Yes

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #2: Thanks you for addressing the comments. The paper is in much better shape now. The figures looks low-quality and blurred, I would only suggest to include high-quality figures in the last version, and further improve the English.

Reviewer #3: The manuscript makes important contributions to the research field and the authors adequately answered the questions of both reviewers. Based on that, I am in favor of its publication.

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

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Reviewer #2: Yes: Abolfazl Razi

Reviewer #3: No