Research On Byzantine Fault Tolerance Mechanism For Cross Chain Environment

With the rapid expansion of the application field on Blockchain technology,heterogeneous Blockchain systems with different technical characteristics and design purposes have emerged one after another.However,the relatively closed technical system between different Blockchains limits the further development of Blockchain.Fortunately,the emergence of Cross Chain technology provides solutions to the communicate and transfer of data onto different Blockchains.Among them,the relay chain scheme using the consensus mechanism realizes the penetration of trust.It retains the decentralization characteristics of Blockchain and enables two chains reach consensus in the form of relay,which has become a hot research direction at present.To propose a Cross Chain consensus scheme with higher efficiency and lower cost,this thesis starts from the Cross Chain environment and explores the Cross Chain consensus scheme.The specific work contents are as follows:Aiming at the trust problem of Cross Chain environment,this thesis analyzes the requirements of Cross Chain environment,the Cross Chain transaction model and the Cross Chain trust mechanism in detail.Based on the Cosmos solution,a Cross Chain transaction model based on Try-Confirm-Cancel is proposed.By using Tendermint consensus engine to provide relay chain consensus service,the model divides the consensus behavior into three parts,which suits for different processing logics and skillfully integrates Cross Chain transactions and consensus.Futher tests have shown that it is more suitable for Cross Chain consensus environment.On the premise of ensuring security,it improves the consensus efficiency and reduces the communication cost.Aiming at the problems of high communication complexity,excessive signature transmission overhead,fixed node rights,elections process with no randomness,this thesis proposes a Cross Chain Byzantine fault tolerant scheme Cross Byzantine Fault Tolerance based on Tendermint scheme,which uses the Ed25519-FROST threshold signature scheme to reduce the communication complexity of consensus process;introduces the Round Trust credit evaluation model to dynamically adjust node rights with the consensus process;provides configurable node elections scheme to flexibly control the scale of the consensus network.Finally,this thesis uses the Hyperledger Fabric platform to build a parallel chain structure,which specifies the standardized Cross Chain data format in the data layer,accesses the CBFT consensus scheme in the consensus layer,and designs the smart contracts for Cross Chain business in the application layer.Then,a Cross Chain consensus system based on the CBFT scheme is finally implemented.