Paper 2020/1351
Tight State-Restoration Soundness in the Algebraic Group Model
Ashrujit Ghoshal and Stefano Tessaro
Abstract
Most efficient zero-knowledge arguments lack a concrete security analysis, making parameter choices and efficiency comparisons challenging. This is even more true for non-interactive versions of these systems obtained via the Fiat-Shamir transform, for which the security guarantees generically derived from the interactive protocol are often too weak, even when assuming a random oracle. This paper initiates the study of state-restoration soundness in the algebraic group model (AGM) of Fuchsbauer, Kiltz, and Loss (CRYPTO '18). This is a stronger notion of soundness for an interactive proof or argument which allows the prover to rewind the verifier, and which is tightly connected with the concrete soundness of the non-interactive argument obtained via the Fiat-Shamir transform. We propose a general methodology to prove tight bounds on state-restoration soundness, and apply it to variants of Bulletproofs (Bootle et al, S&P '18) and Sonic (Maller et al., CCS '19). To the best of our knowledge, our analysis of Bulletproofs gives the first non-trivial concrete security analysis for a non-constant round argument combined with the Fiat-Shamir transform.
Note: Major update with updated security definitions
Metadata
- Available format(s)
-
PDF
- Category
- Foundations
- Publication info
- A major revision of an IACR publication in CRYPTO 2021
- Keywords
- Zero-knowledge proof systemsconcrete securityFiat-Shamir transformAlgebraic Group Modelstate-restoration soundness.
- Contact author(s)
- ashrujit @ cs washington edu
- History
- 2021-06-25: last of 5 revisions
- 2020-10-29: received
- See all versions
- Short URL
- https://ia.cr/2020/1351
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2020/1351,
author = {Ashrujit Ghoshal and Stefano Tessaro},
title = {Tight State-Restoration Soundness in the Algebraic Group Model},
howpublished = {Cryptology {ePrint} Archive, Paper 2020/1351},
year = {2020},
url = {https://eprint.iacr.org/2020/1351}
}
