TetraBFT: Reducing Latency of Unauthenticated, Responsive BFT Consensus

TL;DR

TetraBFT is an unauthenticated Byzantine fault tolerant protocol that achieves low latency, optimal communication, and high resilience without cryptography, suitable for blockchain systems.

Contribution

It introduces TetraBFT, the first unauthenticated BFT protocol with constant storage, optimal communication, and rapid consensus, including pipelined multi-shot extensions.

Findings

TetraBFT achieves consensus in 5 message delays.

It requires only constant local storage.

The protocol is secure against computationally unbounded adversaries.

Abstract

This paper presents TetraBFT, a novel unauthenticated Byzantine fault tolerant protocol for solving consensus in partial synchrony, eliminating the need for public key cryptography and ensuring resilience against computationally unbounded adversaries. TetraBFT has several compelling features: it necessitates only constant local storage, has optimal communication complexity, satisfies optimistic responsiveness -- allowing the protocol to operate at actual network speeds under ideal conditions -- and can achieve consensus in just 5 message delays, which outperforms all known unauthenticated protocols achieving the other properties listed. We validate the correctness of TetraBFT through rigorous security analysis and formal verification. Furthermore, we extend TetraBFT into a multi-shot, chained consensus protocol, making a pioneering effort in applying pipelining techniques to unauthenticated protocols. This positions TetraBFT as a practical and deployable solution for blockchain systems aiming for high efficiency.