Theoretical study of LFT2 consensus algorithm

Abstract

For decentralized and transparent society, blockchain technology has been developed. As consensus algorithm is a core technology for blockchain, quite a few consensus algorithms have been proposed. Consensus algorithms proposed to date can be generally divided into the Nakamoto consensus and Byzantine Fault Tolerance (BFT) based consensus. In this paper, we focus on BFT based consensus. In particular, we deeply analyze on the LFT2 consensus algorithm, which will be used by a blockchain system, ICON. First, we mathematically model the LFT2 consensus algorithm and then analyze safety and liveness, the most important properties in distributed consensus system. Under reasonable assumptions, we prove that LFT2 satisfies safety and liveness. In addition, we compare LFT2 with other BFT based consensus algorithms. Finally, based on the comparison, we show that the trade-offs between BFT-based consensus algorithms exist.