Reversible Data Hiding in Encrypted Image Based on Multi-MSB Embedding Strategy

Round 1

Reviewer 1 Report

Journal: Applied Sciences

Manuscript ID: applsci-737587 

Type of manuscript: Article

TITLE: “Reversible Data Hiding in Encrypted Image Based on Multi-MSB Embedding Strategy”

Authors: Dewang Wang, Xianquan Zhang, Chunqiang Yu, and Zhenjun Tang

Dear Editor,

This work focus on studying the RDHEI method based on multi-MSB embedding strategy with a very high embedding rate. Which includes three steps: (i) The secret bits has been embedded in the encrypted images without any pixel oversaturation in plaintext domain. (ii) The secrets bits has been directly extracted from encrypted domain from the multi-MSB of pixels without any error. Besides, the reconstructed image with very high visual quality has been obtained in the case of the encryption key is only obtained. (iii) Comparison with the other state-of-the-art methods.

The manuscript is very well written and easy to read. The presentation, exhibition of the results are well commented in the text and the bibliography describes well the background on the subject matter and the contributions of the research group. 

This work fulfils, in my opinion, the requirements to be published with optional minor revision.

Best regards,

Reviewer

Here are some detailed comments on the manuscript:

-(Page 1, line 44), you should put here the abbreviation definition of (AES).

-(Page 3, line 145), I think you don't need to define: "|·| is the absolute value function", therefore you should delete it.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

1. Overall the academic writing is below standard. The author need to work on grammatical errors and I recommend proof reading before next submission. 
2. The abstract need to be well written. Currently the abstract is quite vague and it is quite hard to identify the outcome of this project. I recommend the author to quantify the outcome of the research and add it in the abstract.
3.  Introduction part -
• A bit more detailed explanation of the problem is required. The problem formulation is not presented well. 
• Research gap should be supported by well-reviewed literature.
• A thorough literature review is required to understand the gaps.
• The author needs to put past experimental results and achievements so far made in image encryption.
• Line 89-90 need reference.
4. Proposed Method - A flow chart is required to explain the steps in more logical manner.
5. Sec 2.1- Distribution of black pixels around white pixels reveal there are only 3 combinations. The combinations can be more and in this case the author need to define why only 3 cases were chosen.
6. Sec 2.1- Line 140 - explanation f these equations is required
7. Sec 2.2 - In encrypting images the author needs to explain why RC4 is chosen over other encryption techniques.
8. Under Section 4 Experimental Results and Analysis - couple of comments:
•  Line 374 - 376 - The author should include other measuring tools other than histogram. If only histogram is chosen, then it is important to explain a bit more of the choice.
•  Comparisons with related methods - sec 4.3: Why these methods are chosen needs to be explained from literature.
• Need to focus more on the explanation of the results. Explanation of the tables and graphs need more input.
• Further elaborate figure 8 and figure 9. Quantify them and present your actual findings. This will help to build abstract as well. 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

I can see the author has made substantial changes in the paper and all my concerns are addressed properly.