{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,9]],"date-time":"2026-04-09T14:48:07Z","timestamp":1775746087805,"version":"3.50.1"},"reference-count":34,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2025,7,24]],"date-time":"2025-07-24T00:00:00Z","timestamp":1753315200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"European Union\u2014DIGI4ECO project","award":["101112883"],"award-info":[{"award-number":["101112883"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["BDCC"],"abstract":"<jats:p>This study evaluates leadership uniformity\u2014the degree to which the proposer role is evenly distributed among validator nodes over time\u2014in Quorum-based Byzantine Fault Tolerance (QBFT), a Byzantine Fault-Tolerant (BFT) consensus algorithm used in permissioned blockchain networks. By introducing simulated follower timeouts derived from uniform, normal, lognormal, and Weibull distributions, it models a range of network conditions and latency patterns across nodes. This approach integrates Raft-inspired timeout mechanisms into the QBFT framework, enabling a more detailed analysis of leader selection under different network conditions. Three leader selection strategies are tested: Direct selection of the node with the shortest timeout, and two quorum-based approaches selecting from the top 20% and 30% of nodes with the shortest timeouts. Simulations were conducted over 200 rounds in a 10-node network. Results show that leader selection was most equitable under the Weibull distribution with shape k=0.5, which captures delay behavior observed in real-world networks. In contrast, the uniform distribution did not consistently yield the most balanced outcomes. The findings also highlight the effectiveness of quorum-based selection: While choosing the node with the lowest timeout ensures responsiveness in each round, it does not guarantee uniform leadership over time. In low-variability distributions, certain nodes may be repeatedly selected by chance, as similar timeout values increase the likelihood of the same nodes appearing among the fastest. Incorporating controlled randomness through quorum-based voting improves rotation consistency and promotes fairer leader distribution, especially under heavy-tailed latency conditions. However, expanding the candidate pool beyond 30% (e.g., to 40% or 50%) introduced vote fragmentation, which complicated quorum formation in small networks and led to consensus failure. Overall, the study demonstrates the potential of timeout-aware, quorum-based leader selection as a more adaptive and equitable alternative to round-robin approaches, and provides a foundation for developing more sophisticated QBFT variants tailored to latency-sensitive networks.<\/jats:p>","DOI":"10.3390\/bdcc9080196","type":"journal-article","created":{"date-parts":[[2025,7,24]],"date-time":"2025-07-24T11:58:53Z","timestamp":1753358333000},"page":"196","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Leadership Uniformity in Timeout-Based Quorum Byzantine Fault Tolerance (QBFT) Consensus"],"prefix":"10.3390","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0009-0009-6120-5986","authenticated-orcid":false,"given":"Andreas Polyvios","family":"Delladetsimas","sequence":"first","affiliation":[{"name":"Department of Digital Innovation, School of Business, University of Nicosia, Nicosia 2417, Cyprus"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8354-9546","authenticated-orcid":false,"given":"Stamatis","family":"Papangelou","sequence":"additional","affiliation":[{"name":"Department of Digital Innovation, School of Business, University of Nicosia, Nicosia 2417, Cyprus"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4694-8556","authenticated-orcid":false,"given":"Elias","family":"Iosif","sequence":"additional","affiliation":[{"name":"Department of Digital Innovation, School of Business, University of Nicosia, Nicosia 2417, Cyprus"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7824-633X","authenticated-orcid":false,"given":"George","family":"Giaglis","sequence":"additional","affiliation":[{"name":"Department of Digital Innovation, School of Business, University of Nicosia, Nicosia 2417, Cyprus"}]}],"member":"1968","published-online":{"date-parts":[[2025,7,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"43620","DOI":"10.1109\/ACCESS.2021.3065880","article-title":"A Comprehensive Review of Blockchain Consensus Mechanisms","volume":"9","author":"Lashkari","year":"2021","journal-title":"IEEE Access"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Delladetsimas, A.P., Papangelou, S., Iosif, E., and Giaglis, G. 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