基于动态授权的拜占庭容错共识算法的区块链性能改进研究
发布时间：2018-11-13 19:48
【摘要】：随着以比特币为代表的数字货币的风靡,区块链作为其关键底层技术也越来越受各国政府和企业巨头的关注。区块链的去中心化、数据不可篡改性、动态灵活的体系特征,使得其在银行、征信、金融等多领域应用前景非常广泛。但目前区块链系统在交易吞吐量、时延等方面远远无法满足大部分应用场景的性能需求。以工作量证明(POW)、权益证明(POS)为主的公有区块链的TPS只有7不到,一笔交易平均确认时间为10分钟,交易无法篡改的时间更是达到1小时;且POW、POS等共识算法效率低下,耗能严重,无法满足区块链系统性能需求;而Paxos、Raft为代表的传统分布式一致性算法没有考虑拜占庭容错问题,同样不适用于诚实与恶意节点共存的区块链系统;实用拜占庭容错算法设计初衷是面向分布式系统消息、系统指令执行顺序问题而设计的的,采用的是C/S的架构,三阶段的广播协议严重浪费了带宽,静态的网络拓扑结构,无法符合区块链动态对等的系统特征。本文在研究了以上共识算法的原理后,将DPOS算法的授权机制应用到PBFT中,对PBFT加以改进,提出了适用于区块链应用的动态授权拜占庭容错算法。DDBFT相比于PBFT具有以下三方面的优势:1)授权选举机制,共识记账节点专业化并辅以"升降级"机制,动态更新共识记账代表2)精简的共识状态,减少PBFT三阶段共识广播机制带来的网络开销3)去C/S架构,纯P2P网络拓扑,完全符合区块链系统特征最后,用Java程序设计并测试基于DDBFT的区块链系统。实验结果表明,该算法在最佳出块时间20秒的时间间隔下,可以最大限度地利用网路带宽,TPS可以达到10000-12000,时延控制在100-200ms之间,可以满足绝大部分应用系统的性能需求。
[Abstract]:With the popularity of digital currency represented by Bitcoin, block chain, as its key underlying technology, has attracted more and more attention from governments and corporate giants. The decentralization of block chain, the non-tampering of data, and the dynamic and flexible system feature make it widely used in many fields, such as banking, credit information, finance and so on. However, the current blockchain system can not meet the performance requirements of most application scenarios in terms of transaction throughput, delay and so on. The TPS of the public block chain whose (POW), rights and interests are mainly proved by the workload is less than 7, the average confirmation time of a transaction is 10 minutes, and the time that the transaction can not be tampered with is 1 hour. The consensus algorithms such as POW,POS are inefficient and energy-consuming, and can not meet the performance requirements of blockchain systems. The traditional distributed consistency algorithm represented by Paxos,Raft does not take Byzantine fault tolerance into account, nor is it suitable for block chain systems where honest and malicious nodes coexist. The practical Byzantine Fault-Tolerant algorithm was originally designed for distributed system message and system instruction execution order, and adopted the C / S architecture. The three-stage broadcast protocol seriously wasted bandwidth and static network topology. Unable to meet the block chain dynamic peer-to-peer system characteristics. After studying the principle of the above consensus algorithm, this paper applies the authorization mechanism of DPOS algorithm to PBFT, and improves PBFT. This paper proposes a dynamic authorization Byzantine fault-tolerant algorithm for block chain applications. Compared with PBFT, DDBFT has the following three advantages: 1) the mechanism of authorization election, the specialization of consensus accounting node and the mechanism of "upgrade and upgrade". Dynamic updating consensus bookkeeping represents 2) reduced consensus state, reducing network overhead brought by PBFT three-stage consensus broadcasting mechanism 3) removing C / S architecture, pure P2P network topology, completely consistent with block chain system characteristics. The block chain system based on DDBFT is designed and tested by Java program. Experimental results show that the proposed algorithm can make maximum use of the network bandwidth at the optimal time interval of 20 seconds. The TPS can reach 10000-12000, and the time delay is controlled between 100-200ms. It can meet the performance requirements of most application systems.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP311.13
本文编号：2330257
[Abstract]:With the popularity of digital currency represented by Bitcoin, block chain, as its key underlying technology, has attracted more and more attention from governments and corporate giants. The decentralization of block chain, the non-tampering of data, and the dynamic and flexible system feature make it widely used in many fields, such as banking, credit information, finance and so on. However, the current blockchain system can not meet the performance requirements of most application scenarios in terms of transaction throughput, delay and so on. The TPS of the public block chain whose (POW), rights and interests are mainly proved by the workload is less than 7, the average confirmation time of a transaction is 10 minutes, and the time that the transaction can not be tampered with is 1 hour. The consensus algorithms such as POW,POS are inefficient and energy-consuming, and can not meet the performance requirements of blockchain systems. The traditional distributed consistency algorithm represented by Paxos,Raft does not take Byzantine fault tolerance into account, nor is it suitable for block chain systems where honest and malicious nodes coexist. The practical Byzantine Fault-Tolerant algorithm was originally designed for distributed system message and system instruction execution order, and adopted the C / S architecture. The three-stage broadcast protocol seriously wasted bandwidth and static network topology. Unable to meet the block chain dynamic peer-to-peer system characteristics. After studying the principle of the above consensus algorithm, this paper applies the authorization mechanism of DPOS algorithm to PBFT, and improves PBFT. This paper proposes a dynamic authorization Byzantine fault-tolerant algorithm for block chain applications. Compared with PBFT, DDBFT has the following three advantages: 1) the mechanism of authorization election, the specialization of consensus accounting node and the mechanism of "upgrade and upgrade". Dynamic updating consensus bookkeeping represents 2) reduced consensus state, reducing network overhead brought by PBFT three-stage consensus broadcasting mechanism 3) removing C / S architecture, pure P2P network topology, completely consistent with block chain system characteristics. The block chain system based on DDBFT is designed and tested by Java program. Experimental results show that the proposed algorithm can make maximum use of the network bandwidth at the optimal time interval of 20 seconds. The TPS can reach 10000-12000, and the time delay is controlled between 100-200ms. It can meet the performance requirements of most application systems.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP311.13
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