Consistent BFT Performance for Blockchains

There have been numerous solutions to improve the message complexity of Byzantine Fault Tolerant (BFT) protocols. Unfortunately, these solutions do not guarantee consistent performance and fall back to quadratic message complexity if a certain threshold of node failures is encountered in the network. Furthermore, reliance on a single primary to forward a proposed blockchain block to all replicas in the network can provide a potential attack vector, in which the primary can create discrepancies among histories of honest replicas. This results in increased latency during the view change (denial of service). Therefore, we propose a BFT-based protocol that guarantees consistent performance and shifts the reliance from a single primary to broadcast a candidate block to a sub-committee of replicas.