We are thrilled to announce that our esteemed partner University of Nicosia has proceed to a new achievement within the context of DIGI4ECO project.
The article “Leadership Uniformity in Timeout-Based Quorum Byzantine Fault Tolerance (QBFT) Consensus” has been published at “Big data and cognitive computing” Journal, by MDPI.
The authors of the article are: Andreas Polyvios Delladetsimas , Stamatis Papangelou , Elias Iosif and George Giaglis and its respective DOI is the following: https://doi.org/10.3390/bdcc9080196
The abstract and the keywords of the publication can be found below:
Abstract:
This study evaluates leadership uniformity—the degree to which the proposer role is evenly distributed among validator nodes over time—in 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.
QBFT; consensus algorithms; permissioned systems; leadership uniformity; blockchain optimization; distributed consensus
You can reach the full article following this link: https://www.mdpi.com/2504-2289/9/8/196