  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.
