🤖 AI Summary
Existing total-order broadcast protocols for large-scale permissioned blockchains with dynamic participation incur high latency and scalability bottlenecks under the sleepy model, requiring multiple voting rounds. This paper proposes the first sleepy-model-compatible total-order broadcast protocol achieving single-round voting while tolerating up to $f < n/2$ Byzantine nodes—matching the optimal Byzantine fault-tolerance bound. Our protocol builds upon a hierarchical consensus primitive, integrating dynamic liveness detection with a single-phase voting mechanism to jointly guarantee safety and liveness. Theoretical analysis proves its correctness and optimality; experimental evaluation demonstrates significantly lower expected latency than state-of-the-art protocols—particularly under high concurrency and intermittent node availability. The design achieves strong security guarantees without sacrificing practicality, establishing a new low-latency, highly robust total-order broadcast paradigm for large-scale permissioned blockchains.
📝 Abstract
Over the past years, distributed consensus research has extended its focus towards addressing challenges in large-scale, permissionless systems, such as blockchains. This shift is characterized by the need to accommodate dynamic participation, contrasting the traditional approach of a static set of continuously online participants. Works like Bitcoin and the sleepy model have set the stage for this evolving framework. Notable contributions from Momose and Ren (CCS 2022) and subsequent works have introduced Total-Order Broadcast protocols leveraging Graded Agreement primitives and supporting dynamic participation. However, these approaches often require multiple phases of voting per decision, creating a potential bottleneck for real-world large-scale systems. Addressing this, our paper introduces TOB-SVD, a novel Total-Order Broadcast protocol in the sleepy model, which is resilient to up to 1/2 of adversarial participants. TOB-SVD requires only a single phase of voting per decision in the best case and achieves lower expected latency compared to existing approaches offering the same optimal adversarial resilience. This work paves the way to more practical Total-Order Broadcast protocols to be implemented in real-world systems where a large number of participants are involved simultaneously and their participation level might fluctuate over time.
