Revisiting Post-Quantum Fiat-Shamir

Qipeng Liu; Mark Zhandry

Paper 2019/262 Original: eprint.iacr.org/2019/262 ↗

Revisiting Post-Quantum Fiat-Shamir

Qipeng Liu

Mark Zhandry

Abstract

The Fiat-Shamir transformation is a useful approach to building non-interactive arguments (of knowledge) in the random oracle model. Unfortunately, existing proof techniques are incapable of proving the security of Fiat-Shamir in the quantum setting. The problem stems from (1) the difficulty of quantum rewinding, and (2) the inability of current techniques to adaptively program random oracles in the quantum setting. In this work, we show how to overcome the limitations above in many settings. In particular, we give mild conditions under which Fiat-Shamir is secure in the quantum setting. As an application, we show that existing lattice signatures based on Fiat-Shamir are secure without any modifications.

Metadata

Available format(s): PDF
Category: Foundations
Publication info: Preprint.
History: 2019-03-06: last updated; 2019-03-06: published
Short URL: https://ia.cr/2019/262
License: https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2019/262,
      author = {Qipeng Liu and Mark Zhandry},
      title = {Revisiting Post-Quantum Fiat-Shamir},
      howpublished = {Cryptology {ePrint} Archive, Paper 2019/262},
      year = {2019},
      url = {https://eprint.iacr.org/2019/262}
}