Cryptology ePrint Archive: Report 2021/1699

A Compact Digital Signature Scheme Based on the Module-LWR problem*

Hiroki Okada and Atsushi Takayasu and Kazuhide Fukushima and Shinsaku Kiyomoto and Tsuyoshi Takagi

Abstract: We propose a lattice-based digital signature scheme MLWRSign by modifying Dilithium, which is one of the third-Round finalists of NIST’s call for post-quantum cryptographic standards. To the best of our knowledge, our scheme MLWRSign is the first signature scheme whose security is based on the (module) learning with rounding (LWR) problem. Due to the simplicity of the LWR, the secret key size is reduced by approximately 30% in our scheme compared to Dilithium, while achieving the same level of security. Moreover, we implemented MLWRSign and observed that the running time of MLWRSign is comparable to that of Dilithium.

Category / Keywords: public-key cryptography / Lattice Cryptography, Digital Signatures, Learning with Rounding

Original Publication (with minor differences): IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E104.A(9), pp. 1219–1234

Date: received 28 Dec 2021

Contact author: ir-okada at kddi-research jp

Available format(s): PDF | BibTeX Citation

Note: This paper is a revised version of [OTF+21]. We have corrected an error in Eq. (3), and slightly modified the Sign procedure of MLWRSign. See Appendix A for the details.

Version: 20211230:171353 (All versions of this report)

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