Byzantine Consensus in the Random Asynchronous Model

TL;DR

This paper introduces the random asynchronous model, a relaxation of the classic asynchronous network model, enabling Byzantine consensus with probabilistic guarantees under certain thresholds, unlike traditional models.

Contribution

It proposes the random asynchronous model removing adversarial message scheduling and analyzes Byzantine consensus thresholds with probabilistic guarantees.

Findings

Consensus achievable with probabilistic guarantees at different thresholds

Impossibility results establishing limits of consensus in the new model

Comparison with standard asynchronous and partially synchronous models

Abstract

We propose a novel relaxation of the classic asynchronous network model, called the random asynchronous model, which removes adversarial message scheduling while preserving unbounded message delays and Byzantine faults. Instead of an adversary dictating message order, delivery follows a random schedule. We analyze Byzantine consensus at different resilience thresholds ($n=3f+1$, $n=2f+1$, and $n=f+2$) and show that our relaxation allows consensus with probabilistic guarantees which are impossible in the standard asynchronous model or even the partially synchronous model. We complement these protocols with corresponding impossibility results, establishing the limits of consensus in the random asynchronous model.