Research On The Blockchain Consensus Algorithm Based On Practical Byzantine Fault Tolerance Algorithm

With the rise of digital currency,blockchain technology has also developed rapidly,and a large number of scholars and financial technology companies have begun to study blockchain technology.Blockchain is also used in many fields such as finance,traceability,Internet of Things,electronic notarization,etc.due to its decentralization,non-tampering,security and credibility and many other characteristics.As the core of blockchain technology,the consensus mechanism is directly related to the system throughput,transaction delay,fault tolerance and application scenarios.Therefore,how to design a safe and high-performance consensus mechanism has become the difficulty of blockchain development.This article systematically analyzes several mainstream consensus algorithms and finds that the RAFT and PAXOS algorithms have high throughput and low latency,but they are all designed based on Crash Fault Tolerance and are not suitable for the blockchain environment;The security foundation of the POW and POS algorithms is a large amount of computing power and a long delay,which determines that these two algorithms must be high energy consumption and high latency;The DPOS algorithm relies on state to ensure security,so it must issue currency to create equity,but in actual applications,issuing currency is not necessary,but may cause some financial attacks;The PBFT algorithm has superior performance and high security,but some problems will arise when the algorithm is directly applied to the blockchain(1)The scalability is poor,and the system must restart if nodes want to join or exit the network.(2)The communication complexity of the algorithm is high.In this paper,after systematically analyzing the principles of the above consensus algorithm,we have improved the PBFT algorithm and proposed a consensus algorithm suitable for the alliance chain environment,IPBFT.In response to the problem of high communication complexity in the PBFT algorithm,in IPBFT,we introduce a coordination node,which changes the exchange of messages between the two nodes into nodes send message to the coordination node for verification,and the coordination node is verified and then sent to Other nodes,thereby reducing traffic;for the problem of poor scalability of the original algorithm,the new algorithm introduces node join,exit,and recovery protocols,allowing nodes to freely enter and exit the network;for the situation where the error node in the original algorithm repeatedly commits evil,the new algorithm adds the error node removal protocol and the reputation credit mechanism to remove the error node in time to improve system stability.Therefore,compared with PBFT,the improved algorithm has the following advantages:(1)Better scalability.the node can dynamically participate in the network by performing consensus verification on the node's entry or exit.(2)Lower communication complexity.In each round of consensus,a coordination node is randomly selected to participate in the consensus.Through the cooperation of the master node and the coordination node,the communication complexity can be greatly reduced.(3)High system stability.The algorithm introduces the reputation credit mechanism and the error node removal protocol,which cleans up error nodes timely.Finally,we designed a simple blockchain system and tested the performance and function of the IPBFT algorithm.Experimental results show that the IPBFT algorithm is superior to the PBFT algorithm in terms of communication complexity and delay,and is more suitable for the blockchain environment.