Morpheus Consensus: Excelling on trails and autobahns

TL;DR

Morpheus Consensus is a versatile blockchain protocol that adapts between low and high throughput modes, achieving low latency and complexity in both scenarios by morphing between leaderless and leader-based consensus mechanisms.

Contribution

It introduces a novel consensus protocol that dynamically switches between leaderless and leader-based modes, optimizing performance across different throughput conditions.

Findings

Performs comparably to DAG-based protocols during high throughput.

Exhibits lower latency than PBFT and Tendermint during low throughput.

Maintains forkless blockchain production when blocks do not conflict.

Abstract

Recent research in consensus has often focussed on protocols for State-Machine-Replication (SMR) that can handle high throughputs. Such state-of-the-art protocols (generally DAG-based) induce undue overhead when the needed throughput is low, or else exhibit unnecessarily-poor latency and communication complexity during periods of low throughput. Here we present Morpheus Consensus, which naturally morphs from a quiescent low-throughput leaderless blockchain protocol to a high-throughput leader-based DAG protocol and back, excelling in latency and complexity in both settings. During high-throughout, Morpheus pars with state-of-the-art DAG-based protocols, including Autobahn. During low-throughput, Morpheus exhibits competitive complexity and lower latency than standard protocols such as PBFT and Tendermint, which in turn do not perform well during high-throughput. The key idea of Morpheus is that as long as blocks do not conflict (due to Byzantine behaviour, network delays, or high-throughput simultaneous production) it produces a forkless blockchain, promptly finalizing each block upon arrival. It assigns a leader only if one is needed to resolve conflicts, in a manner and with performance not unlike Autobahn.