A CP-ABE Scheme Based on Lattice LWE and Its Security Analysis

Round 1

Reviewer 1 Report

In this paper, the authors get a CP-ABE scheme, which is at least as secure as the original scheme under the same conditions, and has a shorter ciphertext and they provide an innovative design idea for designing CP ABE schemes only based on LWE. The obtained analysis results prove that the performance of the CP ABE innovative design idea. In addition, the structure of this paper is well organized and explanation of key part is clear, thus the paper is easy to understand. However, the reviewer has some comments, as is listed below.

- In subsection 2.2 : Definition 3, the authors show that the Decrypt equation holds if CP-ABE scheme is correct. The authors should more explain CP-ABE decryption process.

- In section 3, the authors present the proof of theorem 2 to prove the efficiency of their algorithms. However, the authors should make more efforts to explain this proof to prove that the CP-ABE scheme selectively secure under linear independence restriction.

- The conclusion must be improved.

Author Response

Dear reviewers,

We have revised the paper according to your request. The details are in the attachment. Please check it. Thank you very much.

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper is devoted to the interesting topic of the construction of a cryptographic CP-ABE scheme.

At present, CP-ABE and multi-authority attribute encryption schemes are actively discussed, but there are not many known efficient solutions for the problem of their construction. Known existing schemes are hard for practical implementation, so are usually replaced by ordinary asymmetric cryptography. In this paper, the authors propose a new CP-ABE with reduced ciphertext length.

The following aspects of the paper can be considered as its strengths:

1. The considered problem is interesting, new, and potentially very practical for future cryptographic applications.

2. Presented solutions are new and interesting.

3. Authors present strict proof for the security and correctness of their scheme.

As possible shortcomings of the paper, the following may be considered:

1. The presentation of the obtained materials is not complete without a proper example of the proposed scheme operating. In view of this, another section with detailed examples must be added to simplify the understanding of the obtained results.

2. There are no practical values of the parameters of the proposed scheme (providing its proper security) mentioned in the paper (parameters are listed in Table 2). So, there is no understanding of the real amount of memory saved for ciphertext storage when using authors' modifications.

3. There is no proper data about the computational complexity of the proposed scheme when compared with the original one.

Anyhow, I must admit that mentioned disadvantages do not reduce the overall positive impression of the presented paper. I think it may be interesting for cryptography research and may be recommended for publishing after proper corrections.

There are a few small typos that can be noted:

1. “A” should not be uppercase in line 95.

2. “this” should be from the capital in line 131.

3. The comma should be after the formula in line 167.

4. The point is missed in 273.

5. “But” must be from the capital in 416.

6. There is just a template information in the Patent section, consider fulfilling or removing it.

Author Response

Dear reviewers,

    We have revised the paper according to your request. The details are in the attachment. Please check it. Thank you very much.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Authors have addressed all my comments.