Paper 2025/1993
A Simplified Round-by-round Soundness Proof of FRI
, zkSecurity, Ethereum FoundationAbstract
The FRI protocol (ICALP '18) is one of the most influential and widely deployed building blocks at the core of modern SNARK systems. While its concrete security is well understood, existing security proofs are intricate and technically complex. In this work, we present a significantly simpler security analysis of FRI, in particular its round-by-round soundness. Our approach is more accessible to a broader audience, lowering the barrier to understanding this fundamental protocol. Furthermore, the simplicity of our analysis may pave the way for future formal verification efforts of modern SNARK constructions.
Note: [Changelog: version 3, 31 Mar. 26] This update adds proofs that FRI upholds stronger security properties and covers batched FRI. [Changelog: version 2, 4 Nov. 25] This update fixes a mistake in the state function for the folding rounds, simplifies the "folding preserves agreement set" lemma and simplifies the proof for the folding rounds. Thank you to Ariel Gabizon for reviewing the previous draft and identifying our mistake.
Metadata
- Available format(s)
-
PDF
- Category
- Cryptographic protocols
- Publication info
- Preprint.
- Keywords
- FRIReed-Solomon codesProximity TestingMutual Correlated AgreementRound-by-round soundness
- Contact author(s)
-
albert @ nethermind io
nico @ zksecurity xyz
benedikt wagner @ ethereum org - History
- 2026-03-31: last of 2 revisions
- 2025-10-24: received
- See all versions
- Short URL
- https://ia.cr/2025/1993
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2025/1993,
author = {Albert Garreta and Nicolas Mohnblatt and Benedikt Wagner},
title = {A Simplified Round-by-round Soundness Proof of {FRI}},
howpublished = {Cryptology {ePrint} Archive, Paper 2025/1993},
year = {2025},
url = {https://eprint.iacr.org/2025/1993}
}
