A Group-Based Optimized Practical Byzantine Fault Tolerance Consensus Algorithm

Abstract

Focusing on the problems of high energy consumption, low efficiency and poor scalability of Practical Byzantine Fault Tolerance (PBFT) consensus algorithm existed in consortium blockchain, this paper presents a group-based optimized Practical Byzantine Fault Tolerance (GPBFT) consensus algorithm, which is a multi-stage algorithm. First, we propose a comprehensive reputation evaluation model to judge the credibility of a node from two aspects of transaction behavior and consensus performance. Then, the nodes with higher reputation value will be selected to enter the consensus group, and the other nodes with block packaging ability are selected as candidate nodes. Finally, we optimize the PBFT based on the application scenario of blockchain, change the three stages to two, which reduces the number of messages delivered by 50% at least. The experimental results demonstrate that GPBFT gains better performance. While ensuring the security and reliability of the system, it shows good scalability, thus it can be used in large-scale consortium blockchain system.