Research And Application Of Practical Byzantine Fault Tolerance Consensus Mechanism On Blockchain

Consensus mechanism is one of the important research directions in the field of blockchain.How to design an efficient and secure consensus mechanism is a hot issue in recent years.Consortium blockchains face challenges in performance,security,and privacy when adopting a Practical Byzantine Fault Tolerance(PBFT)protocol for consensus.Most consortium chains focus on improving protocol performance and scalability while ignoring privacy protection or security.In addition,the consortium chain also has problems such as less coverage of application scenarios and low practicability of the consensus mechanism.In response to the above problems,a comprehensive consortium chain hierarchical consensus mechanism is proposed by combining Schnorr multi-signature,ring signature and PBFT protocol,and applies the consensus mechanism to the institutional employee file consortium chain system to solve the application scenario problem.The main contributions of this thesis are as follows:1.In this thesis,a privacy-protected multi-aggregate signature scheme is proposed,which aims to improve blockchain digital signatures,consensus efficiency and privacy.This scheme can provide nodes with non-anonymous signature,single-anonymous signature and multi-anonymous signature options,and the scheme includes a multisignature function.After multiple nodes sign the same data,an efficient short signature can be generated for verification.In this thesis,the security and anonymity of the scheme is proved through theoretical analysis,and the advantage of the scheme in terms of signature efficiency is proved through performance experiments.2.In this thesis,an improved layered PBFT consensus mechanism is proposed,which aims to improve the consensus network architecture for consensus efficiency.The proposed consensus adopts a layered structure to divide the consensus network.Each level contains multiple clusters,and nodes in the cluster can participate in a consensus,and after the intra-cluster consensus is completed,the block will be transmitted to the upper layer.The use of a layered architecture can prevent nodes that are not closely related or far apart from participating in specific consensus,which can overcome the scalability defect of PBFT and ensure decentralization.In this thesis,the rationality and application scenarios of the scheme is proved through theoretical analysis,and the advantages of the scheme in terms of consensus efficiency is proved through performance experiments.3.In this thesis,a scheme that combines improved PBFT and personal file consortium chain scenario is proposed.This combination scheme is used to design and implement the personal file consortium chain system of institutional employees.The consortium chain can provide secure,credible and authoritative file management.The system maps employees to nodes in a multi-layer consensus network,and employee levels to levels in the consensus.In this way,the file proposer and related employees can participate in the specific consensus to improve the transparency and authority of the files.In this thesis,the signature module,block construction module,consensus module,blockchain query and storage module are designed respectively,and a prototype system with basic consensus function is realized,which proves the practicability of the consensus theory in this thesis.