Improvement And Implementation Of Byzantine Fault Tolerance Consensus Algorithm Based On Verifiable Random Function

Blockchain technology is the prototype of the next generation of cloud computing.It is expected to completely reshape human social activities like the Internet and realize the transition from the current information Internet to the value Internet.The consensus algorithm is the core of the blockchain technology,enabling the blockchain to build a decentralized trusted system without trusting a single node.The consensus algorithm can directly affect the performance of the blockchain,and the success of Bitcoin is inseparable from the clever design of Proof of Work(Po W).However,all of the current mainstream consensus algorithms have obvious defects.The Po W,which is used by Bitcoin,has been criticized by researchers for its waste of resources caused by computing power competition in the consensus process.The Practical Byzantine Fault Tolerance(PBFT)is suitable for the Consortium Blockchain,but its C/S architecture against decentralization and lack of support for the dynamic joining and exiting of the consensus nodes are both issues to be solved.Implementation of Raft is complex and it has no Byzantine fault tolerance,so that it is difficult to apply it to the Public Blockchain and the Consortium Blockchain.Due to the small number of transactions per second,such as Bitcoin and Ethereum,various consensus algorithms have emerged in recent years.More and more consensus algorithms are designed to participate in consensus by some nodes to improve the transaction speed,and this requires ensuring the fairness of the process of generating partial nodes.Verifiable Random Function(VRF)can generate a random number and can verify that the random number is indeed generated by someone,which can be used as a solution to generate consensus nodes fairly.A VRF-based Byzantine fault-tolerant consensus algorithm RBFT is proposed in this thesis.The main contribution are as follows:1.In the Ethereum derivative application Quorum,the performance experiment of the classical consensus algorithm was carried out,and the improvement direction was summarized by analyzing the experimental results;2.A number of improvements have been made to PBFT,including node addition and subtraction dynamization,replacement to P2 P network model,and other improvements to accelerate the consensus process;3.It introduces VRF for node lottery and provides verification capability.Combined with Po S,it improves security and fairness;4.Implement RBFT in Quorum and directly applied to the corporate Consortium Blockchain.The experimental results have obtained the actual results of RBFT,and have obvious advantages in performance,scalability and security compared to PBFT,Raft,Po W and other algorithms.