Cryptology ePrint Archive: Report 2019/606

An Efficient and Provable Masked Implementation of qTESLA

François Gérard and Mélissa Rossi

Abstract: Now that the NIST's post-quantum cryptography competition has entered in its second phase, the time has come to focus more closely on practical aspects of the candidates. While efficient implementations of the proposed schemes are somewhat included in the submission packages, certain issues like the threat of side-channel attacks are often lightly touched upon by the authors. Hence, the community is encouraged by the NIST to join the war effort to treat those peripheral, but nonetheless crucial, topics. In this paper, we study the lattice-based signature scheme qTESLA in the context of the masking countermeasure. Continuing a line of research opened by Barthe et al. at Eurocrypt 2018 with the masking of the GLP signature scheme, we extend and modify their work to mask qTESLA . The masking can be done at any order and specialized gadgets are used to get maximal efficiency at order 1. We implemented our countermeasure in the original code of the submission and did tests at different orders to assess the feasibility of our technique.

Category / Keywords: public-key cryptography / lattice-based signature masking side-channel nist qtesla

Date: received 30 May 2019

Contact author: fragerar at ulb ac be, melissa rossi@ens fr

Available format(s): PDF | BibTeX Citation

Version: 20190602:113640 (All versions of this report)

Short URL: ia.cr/2019/606


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