2026-07-26T17:22:35Z https://drops.dagstuhl.de/oai

oai:drops-oai.dagstuhl.de:22556 2025-10-02T11:06:12Z ddc:004 open_access

How Robust Are Synchronous Consensus Protocols? Milošević, Nenad Cason, Daniel Milošević, Zarko Pedone, Fernando Synchronous Consensus Byzantine Failures Blockchain Synchronous Byzantine fault-tolerant (BFT) protocols have long been a reality in an academic setting, yet their practicality remains debated. The main concern of skeptics of synchronous systems is that the correctness of these protocols depends on the timely delivery of all messages within a predefined synchronous bound, Δ. This dependency creates a challenging tradeoff between protocol correctness and performance, as Δ directly impacts both. In this paper, we examine this tradeoff in detail. Specifically, we introduce BoundBFT, a new synchronous BFT consensus protocol. We analyze how BoundBFT’s correctness can be compromised and use this analysis to design and implement the most effective attack strategies that malicious processes could employ. Furthermore, we experimentally determine the synchronous bound Δ that provides sufficient confidence in maintaining protocol correctness even in the presence of malicious replicas. Finally, we apply this discovered bound to BoundBFT, evaluate its performance, and compare it to state-of-the-art synchronous and partially synchronous protocols. Schloss Dagstuhl – Leibniz-Zentrum für Informatik Nenad Milošević and Daniel Cason and Zarko Milošević and Fernando Pedone 2025 Is Part Of LIPIcs, Volume 324, 28th International Conference on Principles of Distributed Systems (OPODIS 2024) InProceedings Text doc-type:ResearchArticle publishedVersion application/pdf doi:10.4230/LIPIcs.OPODIS.2024.20 urn:nbn:de:0030-drops-225560 https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.OPODIS.2024.20 eng https://creativecommons.org/licenses/by/4.0/legalcode