ThermoEquil: a secure protocol for committee-based permissionless blockchains

Abstract

Proof of work, as a widely accepted method, is limited by its low throughput. A significant approach toovercoming the performance and scalability limitations is to make hybrid blockchains by combining proofof work with other decentralized systems. The committee-based protocol is proposed to split the overheadsof processing transactions among multiple, smaller groups of nodes to work in parallel to maximizeperformance. However, most existing solutions compromise security or decentralization because of the highdemand for hash power in proof of work. We present a novel distributed ledger that preserves long-termsecurity under permissionless operation. Our design follows the same premise with proof of work but haslow demand for hash power and no limitation for scalability. It ensures security and correctness by manymember exchanges that guarantee the percentage of honest nodes. Our detailed mathematical modelingand calculation prove the security of the protocol. An evaluation of our experimental prototype shows thatour protocol has the same security as proof of work and can tolerate less than 50% adversaries. Ourexperimental results show the effectiveness of our work is the best than the other three popular protocols.The transaction processing speed is more than ten times that of proof of work. We believe it can be usedwidely instead of proof of work in many scenarios.