International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Lattice-Based Blind Signatures, Revisited

Eduard Hauck , Ruhr University Bochum
Eike Kiltz , Ruhr University Bochum
Julian Loss , University of Maryland, College Park
Ngoc Khanh Nguyen , IBM Research - Zurich
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Conference: CRYPTO 2020
Abstract: We observe that all previously known lattice-based blind signatures schemes contain subtle flaws in their security proofs (e.g.,~Rückert, ASIACRYPT '08) or can be attacked (e.g., BLAZE by Alkadri et al., FC~'20). Motivated by this, we revisit the problem of constructing blind signatures from standard lattice assumptions. We propose a new three-round lattice-based blind signature scheme whose security can be proved, in the random oracle model, from the standard SIS assumption. Our starting point is a modified version of the insecure three-round BLAZE scheme, which itself is based Lyubashevsky's three-round identification scheme combined with a new aborting technique to reduce the correctness error. Our proof builds upon and extends the recent modular framework for blind signatures of Hauck, Kiltz, and Loss (EUROCRYPT~'19). It also introduces several new techniques to overcome the additional challenges posed by the correctness error which is inherent to all lattice-based constructions. While our construction is mostly of theoretical interest, we believe it to be an important stepping stone for future works in this area.
Video from CRYPTO 2020
  title={Lattice-Based Blind Signatures, Revisited},
  author={Eduard Hauck and Eike Kiltz and Julian Loss and Ngoc Khanh Nguyen},