Synchronous Hybrid Message-Adversary

TL;DR

This paper introduces the Hybrid Message-Adversary model, a novel synchronous framework for analyzing distributed systems with Byzantine faults, simplifying analysis by focusing on message delivery issues rather than processor failures.

Contribution

It proposes a new synchronous model that captures message adversaries, enabling easier analysis of Byzantine faults and revealing phenomena not seen in previous models.

Findings

Hybrid model effectively emulates real-world message failures.

It allows analysis of Byzantine faults in a simplified synchronous setting.

Reveals new phenomena in distributed fault tolerance.

Abstract

The theory of distributed computing, lagging in its development behind practice, has been biased in its modelling by employing mechanisms within the model mimicking reality. Reality means, processors can fail. But theory is about predicting consequences of reality, hence if we capture reality by "artificial models," but those nevertheless make analysis simpler, we should pursue the artificial models. Recently the idea was advocated to analyze distributed systems and view processors as infallible. It is the message delivery substrate that causes problems. This view not only can effectively emulate reality, but above all seems to allow to view any past models as \emph{synchronous} models. Synchronous models are easier to analyze than asynchronous ones. Furthermore, it gives rise to models we haven't contemplated in the past. One such model, presented here, is the Hybrid Message-Adversary. We motivate this model through the need to analyze Byzantine faults. The Hybrid model exhibits a phenomenon not seen in the past.