Research On Public Welfare Donation Traceability System And Consensus Algorithm Based On Blockchain

With the rapid development of public welfare informatization,the security and transparency of public welfare donation information have become particularly important.Aiming at the problems of opaque and untraceable donation flow and easy tampering of donation information in charity.The thesis designed and implemented a traceability system based on blockchain combined with the advantages of blockchain technology.At the same time,aiming at the low performance of consensus algorithm in traceability system,a blockchain consensus mechanism suitable for traceability scenario of charity is proposed.The system takes blockchain as the underlying service architecture of the whole platform,designs and explains the workflow and system architecture of the system.Set up four organizations corresponding to donors,recipients,charities and regulatory authorities,and build a Fabric network module.The intelligent contract technology is used to realize the business functions such as uploading to the blockchain and traceability of donation information,and introduce the encrypted transmission module to prevent the disclosure of private information.Finally,the system is developed and implemented on the open source blockchain framework Fabric,which verifies the feasibility of the traceability system’s function and performance,and compared it with the charity system based on other technical solutions.An improved PBFT algorithm based on grouping Raft mechanism is proposed,which is named K-DGRPBFT algorithm.By analyzing the problems of Raft algorithm and PBFT algorithm,clarified the design goal of consensus algorithm.Combining the high consensus efficiency of Raft algorithm with the tolerance of Byzantine errors of PBFT algorithm,a K-DGRPBFT algorithm suitable for the traceability scene of public welfare donations is proposed.The algorithm improves the original global consensus to a multi-centered two-level consensus,in which the intra-group consensus adopts an improved Raft consensus mechanism,introduces supervisory nodes to improve the security of intra-group consensus,and makes the leaders of intra-group consensus form a consensus committee to reach consensus among groups.An improved PBFT algorithm is adopted for inter-group consensus.For the state setting evaluation mechanism of nodes,the nodes divide into candidate nodes,ordinary nodes and invalid nodes.The status of the node is transformed according to the credit value,the random election of the primary node is improved to the election based on the node credit value,and the original three-stage submission is optimized to two stages,which simplifies the implementation process of the consistency protocol and improves the consensus efficiency of nodes.Experimental results show that K-DGRPBFT algorithm performs better than other consistency algorithms in consistency delay,communication overhead and throughput.