Research And Implementation On Consensus Algorithm Of Blockchain Based On Ethereum

With the continuous development of blockchain technologies such as Ethereum,smart contracts,and consensus algorithms,blockchain technology has changed from a single financial field to smart medical,smart transportation,and smart government affairs that are closely related to people's lives.As one of the core technologies of the blockchain,the consensus algorithm directly affects the performance of the blockchain system(such as transaction throughput,scalability,and fault tolerance)and then affects people's quality of life.To this end,this thesis studies the mainstream consensus algorithms such as Proof of Work(PoW),Proof of Stake(PoS)and Delegated Proof of Stake(DPoS).It also focuses on the problems existing in the current DPOS consensus algorithm with high usage rate.The main research contents of this thesis are as follows:(1)Aiming at the problems of DPoS consensus algorithm such as low enthusiasm of voting nodes and easy selection of malicious nodes as proxy nodes,a reputation-based Delegated Proof of Stake(RDPoS)consensus algorithm is proposed.In the RDPoS consensus algorithm,the reputation model is first used to evaluate the historical behavior of the node to obtain the reputation value of the node,and then a comprehensive score is made based on the reputation value and the number of votes,and finally the proxy node is selected to participate in block generation and verification based on the comprehensive score.In addition,the introduction of a hybrid incentive mechanism into the RDPoS consensus algorithm improves the enthusiasm of nodes to vote through reputation rewards.The experimental results prove that the RDPoS consensus algorithm can effectively reduce the probability of malicious nodes being selected as proxy nodes under the premise of ensuring the enthusiasm of nodes to vote.(2)In the RDPoS consensus algorithm,nodes still use the voting method of the DPoS consensus algorithm when voting.The number of votes obtained by the voted node is proportional to the number of tokens owned by the voting node(total number of votes = number of votes * number of tokens),which will affect the fairness of the proxy node selection in the RDPoS consensus algorithm.Based on the RDPoS consensus algorithm,a Delegated Proof of Stake based on Voting Trust Model(DPoSVT)is proposed to solve the problem of unfair proxy node selection.In the DPoSVT consensus algorithm,first use the voting trust model to evaluate the voting situation of the entire network to obtain the trust value of the node,and then perform a comprehensive score based on the trust value of the node,the reputation value in the RDPoS consensus algorithm and the number of votes of the node,and finally according to the comprehensive score,the proxy node is selected to participate in block generation and verification.The experimental results prove that the DPoSVT consensus algorithm can effectively reduce the probability of malicious nodes being selected as proxy nodes under the premise of ensuring the fairness of node voting.(3)Use the DPoSVT consensus algorithm to replace the PoW consensus algorithm in Ethereum,and design and implement a decentralized electronic medical record management system based on the improved Ethereum platform.Tests on all functions in the system prove that the Ethereum platform improved based on the DPoSVT consensus algorithm can meet the basic requirements of the electronic medical record management system.