Byzantine Fault Tolerance for Nondeterministic Applications

TL;DR

This paper introduces a systematic classification and handling mechanisms for nondeterminism in Byzantine fault-tolerant systems, addressing a gap in managing complex nondeterministic behaviors in practical applications.

Contribution

It provides a comprehensive classification of nondeterminism types and designs core mechanisms to handle them within BFT systems, improving replica consistency.

Findings

Classified common nondeterminism types relevant to BFT

Developed core mechanisms for handling nondeterminism

Enhanced BFT replica consistency in nondeterministic applications

Abstract

All practical applications contain some degree of nondeterminism. When such applications are replicated to achieve Byzantine fault tolerance (BFT), their nondeterministic operations must be controlled to ensure replica consistency. To the best of our knowledge, only the most simplistic types of replica nondeterminism have been dealt with. Furthermore, there lacks a systematic approach to handling common types of nondeterminism. In this paper, we propose a classification of common types of replica nondeterminism with respect to the requirement of achieving Byzantine fault tolerance, and describe the design and implementation of the core mechanisms necessary to handle such nondeterminism within a Byzantine fault tolerance framework.