Byzantine fault-tolerant (BFT) state machine replication (SMR) has been studied for over 30 years. Recently it has received more attention due to its application in permissioned blockchain systems. A sequence of research efforts focuses on improving the commit latency of the SMR protocol in the common good case, including PBFT with $3$-round latency and $n\geq 3f+1$ and FaB with $2$-round latency and $n\geq 5f+1$. In this paper, we propose an authenticated protocol that solves $2$-round BFT S...
