Cryptology ePrint Archive: Report 2021/1565

Practical, Round-Optimal Lattice-Based Blind Signatures

Shweta Agrawal and Elena Kirshanova and Damien Stehle and Anshu Yadav

Abstract: Blind signatures have numerous applications in privacy-preserving technologies. While there exist many practical blind signatures from number-theoretic assumptions, the situation is far less satisfactory from post-quantum assumptions. In this work, we provide the first round-optimal, practical lattice based blind signature.

Our scheme relies on the Gentry, Peikert and Vainkuntanathan signature [STOC’08] and non-interactive zero-knowledge proofs for linear relations with small unknowns, which are significantly more efficient than their general purpose counterparts. Its security stems from a new and arguably natural assumption which we introduce: one-more-ISIS. This assumption can be seen as a lattice analogue of the one-more-RSA assumption by Bellare et al [JoC’03]. To gain confidence, we provide a detailed overview of diverse attack strategies.

Category / Keywords: public-key cryptography / Blind signatures, practical, round-optimal, lattices

Date: received 29 Nov 2021, last revised 16 Mar 2022

Contact author: shweta a at cse iitm ac in, elenakirshanova at gmail com, damien stehle at ens-lyon fr, anshu yadav06 at gmail com

Available format(s): PDF | BibTeX Citation

Note: This version does not contain one of the constructions from the earlier version. That construction has been substantially improved and will appear as a separate report.

Version: 20220316:143808 (All versions of this report)

Short URL: ia.cr/2021/1565