A Searchable Encryption with Forward/Backward Security and Constant Storage
Round 1
Reviewer 1 Report
This paper proposes a dynamic searchable encryption in public-key setting. The new construction possesses forward and backward security under the RSA-Trapdoor Decisional Diffie-Hellman (n-TDDH) assumption and consists of a two-layer structure, Document Index Chain and Keyword Index Chain. The proposed bilinear pairing free scheme consumes lower computational overhead as compared to most existing bilinear pairing based schemes. The scheme uses nested hash function which leads to slightly higher computational overhead but it is still acceptable as the operation overhead of hash function is lower than that of bilinear pairing. The proposed scheme outperforms the existing schemes in terms of search time and update time with the increasing of number of keywords. In addition, the use of a two-layer structure helps to achieve constant storage cost on client-side. This structure shows significant advantage when the number of keywords increases.
The overall presentation and technical contribution of the paper is weak. Please find a few technical concerns as highlighted below:
- - A third party KGC is involved in the key generation which I believe is the Key Generator Center used to be referred in certificateless cryptographic schemes. However, the generation of both public and private keys by this KGC which seems odd from the viewpoint of the trust level. Please provide justifications if this is an appropriate setting.
- - No formal security notion and security analysis is provided. There is no formal theorem statement provided in Section 5 Security Analysis too.
- - Besides forward and backward security, the relevant security notions and security analysis for PEKS should be discussed too.
- - Please check the definition in Section 2.1, the n-TDDH problem on the adversarial advantage which does not seem right.
S Some obvious grammatical errors:
- Bilinear pairs -> bilinear pairings
- Please include a space before citing the references, e.g. servers(space)[2, 3].
- l.116: as follows
- l.159-160: The client user uploads the ciphertext to the server after encrypting the plaintext with the public key.
- Please check and improve the typesetting of all mathematical expressions.
- l.199: User calculates
- l.360: We proposed
Author Response
Dear reviewer:
Thank you for your careful review. Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our research. We have studied the comments carefully and have made a correction which we hope meet with approval.
We have provided a point-by-point response in the attachment.
We would love to thank you for allowing us to resubmit a revised copy of the manuscript and we highly appreciate your time and consideration.
Sincerely yours
Junjian Yan
Author Response File: 
Author Response.docx
Reviewer 2 Report
The research topic is excellent. However, very few improvements required.
There is no mention of research design/theoretical framework adopted. What type of methodology was used to conduct this study? Which other studies used similar methodology?
Comments for author File: 
Comments.pdf
Author Response
Dear reviewer:
Thank you for your precious comments and advice. Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our research. We have studied the comments carefully and have made a correction which we hope meet with approval.
We have provided a point-by-point response in the attachment.
We would love to thank you for allowing us to resubmit a revised copy of the manuscript and we highly appreciate your time and consideration.
Sincerely yours
Junjian Yan
Author Response File: Author Response.docx
