Carnot: A highly Scalable and Responsive BFT Consensus protocol

TL;DR

Carnot is a scalable, responsive BFT consensus protocol that reduces authenticator verification complexity, enabling efficient operation in large networks of tens to hundreds of thousands of nodes with instant finality.

Contribution

Carnot introduces a novel verification and aggregation method that streamlines authenticator processing, significantly improving scalability over existing protocols.

Findings

Operates efficiently with $O(log(N))$ authenticators per node

Scales to networks with hundreds of thousands of nodes

Achieves wire-speed operation with instant finality

Abstract

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.