Paper 2026/355

Forget-IT: Optimal Good-Case Latency For Information-Theoretic BFT

Ittai Abraham, a16z Crypto Research
Sourav Das, Category Labs
Yuval Efron, Ritual
Jovan Komatovic, Category Labs
Abstract

The good-case latency of a consensus protocol measures the latency from block proposal by a consensus leader to decision, in the case in which the leader is correct. It is arguably the efficiency metric most pertinent for discussing the practical latency performance of consensus protocols. Well understood in the context of the authenticated setting, with PBFT [Castro 99], Tendermint [Buchman 16] & Simplex [Chan, Pass 23] achieving the optimal good-case latency of 3 rounds, significant gaps remain in the unauthenticated setting. We present Forget-IT, an unauthenticated consensus protocol with optimal good-case latency of 3 rounds. Furthermore, our protocol only requires constant persistent storage, and has $O(n^2)$ message complexity per view.

Metadata
Available format(s)
PDF
Category
Applications
Publication info
Preprint.
Keywords
Byzantine agreementgood-case latency
Contact author(s)
ittaia @ gmail com
souravdas1547 @ gmail com
efronyuv @ gmail com
jovan komatovic @ gmail com
History
2026-02-23: approved
2026-02-22: received
See all versions
Short URL
https://ia.cr/2026/355
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2026/355,
      author = {Ittai Abraham and Sourav Das and Yuval Efron and Jovan Komatovic},
      title = {Forget-{IT}: Optimal Good-Case Latency For Information-Theoretic {BFT}},
      howpublished = {Cryptology {ePrint} Archive, Paper 2026/355},
      year = {2026},
      url = {https://eprint.iacr.org/2026/355}
}
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