一种面向区块链的优化PBFT共识算法

An optimized PBFT consensus algorithm for blockchain

区块链技术具有去中心化,数据不可篡改和数据透明等特点,使得该技术的应用领域不断扩展,但目前应用于区块链系统的共识算法存在着资源浪费和共识效率较低等问题,限制了区块链技术的发展.针对此问题,基于实用拜占庭容错算法(Practical Byzantine Fault Tolerance,PBFT),算法的基本思想,提出了一种优化的共识算法.该算法引入积分机制,根据节点积分挑选参与共识的节点,以降低网络中的通信开销;在不存在拜占庭节点的情况下,优化PBFT算法的一致性协议;引入升降级机制,动态更新参与共识的节点集合,以保证算法在大部分时间内都执行优化一致性协议.实验结果表明:与PBFT算法相比,本文提出的共识算法将共识过程的时间复杂度从O(N^2)下降到O(N),有效降低了网络中的通信开销,平均时延从55ms降到37ms,平均吞吐量从342TPS提升到677TPS.

Blockchain technology has the characteristics of decentralization,data tamper-resistantand data transparency,which makes the application field of blockchain technology expand continuously.However,the consensus algorithm applied to the blockchain system currently has problems of resource waste and low efficiency,which limits the development of blockchain technology.Aiming at this problem,this paper proposes an optimized consensus algorithm based on the basic idea of PBFT(Practical Byzantine Fault Tolerance)algorithm.This algorithm introduces an integration mechanism to select nodes participating in the consensus based on node points to reduce communication overhead in the network,and optimizes the consistency protocol of the PBFT algorithm in the absence of Byzantine nodes.It also introduces a lifting level mechanism to dynamically update the nodes participating in the consensus process to ensure that the algorithm performs the optimized coherence protocol most of the time.The experiment results show that the new consensus algorithm reduces the time complexity of the consensus process from O(N^2)to O(N),which effectively reduces the communication overhead in the network,and decreases average delay from 55 ms to 37 ms,increases average throughput from 342 TPS to 677 TPS,as compared to the original PBFT algorithm.