2026-07-23T22:18:41Z https://drops.dagstuhl.de/oai

oai:drops-oai.dagstuhl.de:24875 2026-02-09T07:42:17Z ddc:004 open_access

Brief Announcement: Carry the Tail in Consensus Protocols Gupta, Suyash Kang, Dakai Malkhi, Dahlia Sadoghi, Mohammad Consensus Blockchain BFT We present Carry-the-Tail, the first deterministic atomic broadcast protocol in partial synchrony that, after GST, simultaneously guarantees two desirable properties: (i) a constant fraction of commits are proposed by non-faulty leaders against tail-forking attacks, and (ii) optimal, worst-case quadratic communication under a cascade of faulty leaders. The solution also guarantees linear amortized communication, i.e., the steady-state is linear. Combining these two desirable properties was not simultaneously achieved previously: on one hand, prior atomic broadcast solutions achieve per-view linear word communication complexity. However, they face a significant degradation in throughput under tail-forking attack. On the other hand, existing solutions to tail-forking attacks require either quadratic communication steps or computationally-prohibitive SNARK generation. The key technical contribution is Carry, a practical drop-in mechanism for streamlined protocols in the HotStuff family. Carry guarantees good performance against tail-forking and removes most leader-induced stalls, while retaining linear traffic and protocol simplicity. Carry-the-Tail implements the Carry mechanism on HotStuff-2. Schloss Dagstuhl – Leibniz-Zentrum für Informatik Suyash Gupta and Dakai Kang and Dahlia Malkhi and Mohammad Sadoghi 2025 Is Part Of LIPIcs, Volume 356, 39th International Symposium on Distributed Computing (DISC 2025) InProceedings Text doc-type:ResearchArticle publishedVersion application/pdf doi:10.4230/LIPIcs.DISC.2025.59 urn:nbn:de:0030-drops-248759 https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.DISC.2025.59 eng https://creativecommons.org/licenses/by/4.0/legalcode