Unraveling Responsiveness of Chained BFT Consensus with Network Delay

TL;DR

This paper models and evaluates the responsiveness of chained BFT consensus protocols using a Markov Decision Process framework, revealing nuanced effects of responsiveness on protocol robustness and performance under various attack scenarios.

Contribution

It introduces a unified MDP-based framework for analyzing chained BFT protocols, providing new insights into attack strategies and the impact of responsiveness on protocol performance.

Findings

Responsiveness is not always beneficial for protocol performance.

Optimal attack strategies can be systematically derived using MDP analysis.

Experimental validation confirms theoretical insights across diverse scenarios.

Abstract

With the advancement of blockchain technology, chained Byzantine Fault Tolerant (BFT) protocols have been increasingly adopted in practical systems, making their performance a crucial aspect of the study. In this paper, we introduce a unified framework utilizing Markov Decision Processes (MDP) to model and assess the performance of three prominent chained BFT protocols. Our framework effectively captures complex adversarial behaviors, focusing on two key performance metrics: chain growth and commitment rate. We implement the optimal attack strategies obtained from MDP analysis on an existing evaluation platform for chained BFT protocols and conduct extensive experiments under various settings to validate our theoretical results. Through rigorous theoretical analysis and thorough practical experiments, we provide an in-depth evaluation of chained BFT protocols under diverse attack scenarios, uncovering optimal attack strategies. Contrary to conventional belief, our findings reveal that while responsiveness can enhance performance, it is not universally beneficial across all scenarios. This work not only deepens our understanding of chained BFT protocols, but also offers valuable insights and analytical tools that can inform the design of more robust and efficient protocols.