We present HotStuff, a leader-based Byzantine fault-tolerant replication
protocol for the partially synchronous model. Once network communication
becomes synchronous, HotStuff enables a correct leader to drive the protocol to
consensus at the pace of actual (vs. maximum) network delay--a property called
responsiveness--and with communication complexity that is linear in the number
of replicas. To our knowledge, HotStuff is the first partially synchronous BFT
replication protocol exhibiting these combined properties. HotStuff is built
around a novel framework that forms a bridge between classical BFT foundations
and blockchains. It allows the expression of other known protocols (DLS, PBFT,
Tendermint, Casper), and ours, in a common framework.
Our deployment of HotStuff over a network with over 100 replicas achieves
throughput and latency comparable to that of BFT-SMaRt, while enjoying linear
communication footprint during leader failover (vs. quadratic with BFT-SMaRt).