  We present Carnot, a leader-based Byzantine Fault Tolerant (BFT) consensus
protocol that is responsive and operates under the partially synchronous model.
Responsive BFT consensus protocols exhibit wire-speed operation and deliver
instantaneous finality, thereby addressing a fundamental need in distributed
systems. A key challenge in scaling these protocols has been the computational
complexity associated with authenticator verification. We demonstrate that
Carnot effectively addresses this bottleneck by adeptly streamlining the
verification and aggregation of $O(log(N))$ authenticators per node. This
notable advancement marks a substantial improvement over the prevailing $O(N)$
state-of-the-art approaches. Leveraging this inherent property, Carnot
demonstrates its capacity to seamlessly scale to networks comprising tens to
hundreds of thousands of nodes. We envision Carnot as a critical stride towards
bridging the gap between classical BFT consensus mechanisms and blockchain
technology.
