OciorCOOL: Faster Byzantine Agreement and Reliable Broadcast

TL;DR

OciorCOOL improves upon the COOL Byzantine agreement protocol by reducing communication rounds, and it also introduces an optimal reliable broadcast protocol with fewer rounds, enhancing efficiency in distributed systems.

Contribution

The paper presents OciorCOOL, an optimized Byzantine agreement protocol with fewer communication rounds, and a new reliable broadcast protocol with optimal round complexity.

Findings

OciorCOOL reduces one communication round compared to COOL.

The reliable broadcast protocol requires only six rounds, which is optimal.

The protocols maintain correctness and efficiency in Byzantine settings.

Abstract

COOL (Chen'21) is an error-free and deterministic Byzantine agreement protocol that achieves consensus on an $\ell$-bit message with a communication complexity of $O(\max\{n\ell, n t \log t \})$ bits in four phases, given $n\geq 3t + 1$, for a network of $n$ nodes, where up to $t$ nodes may be dishonest. In this work we show that COOL can be optimized by reducing one communication round. The new protocol is called OciorCOOL. Additionally, building on OciorCOOL, we design an optimal reliable broadcast protocol that requires only six communication rounds.