Research On Efficient And Robust Dual Consensus Mechanism In Blockchain

With the great success achieved by digital currencies such as Bitcoin,blockchain technology as its underlying technology has gained widespread attention from domestic and international scholars.Blockchain has applied in many fields such as the Internet of Things,supply chain,medical data sharing and trusted data management.Consensus protocols are the core technological innovation driving blockchain applications and are used to ensure the consistency of the copies of data maintained by all nodes.However,existing consensus protocols face problems such as high security threats,extended transaction latency and low throughput,making it difficult to provide good service for blockchain applications.Based on this,this thesis conducts a study on efficient and robust dual consensus mechanism in blockchain based on the analysis of existing consensus protocol.First,this thesis proposes ERSCP,a synchronous consensus protocol with robustness,scalability,and high performance.ERSCP utilizes a verifiable random function to elect a small committee to perform an improved PBFT consensus that can be applied to blockchain networks consisting of large-scale nodes;Uses reputation as a node’s stake to resist Sybil attacks while designing an improved logistic regression model to evaluate reputation to increase the cost of Stake-grinding and bribery attacks by malicious nodes;And adds a pre-commit phase to reduce the number of communications between nodes,improving the performance of the protocol.Second,an asynchronous consensus protocol with robustness,decentralization and high performance(ERACH)is proposed to address the problem that ERSCP relies on the weak synchronization assumption and cannot be effectively applied to network link unreliability scenarios.ERACH uses cryptography to guarantee the robustness of the protocol;A distributed hashing algorithm is used to elect a committee containing at least one honest node to perform the improved Honey Badger consensus,which reduces the number of runs of the Honey Badger submodule and thus significantly improves the performance of the protocol;Threshold signatures use the improved Schnorr algorithm based on multi-party computation,which reduces the reliance on trusted third parties and ensures the decentralized nature of the protocol.ERSCP is suitable for the case of stable networks and ERACH is suitable for the case of sufficient computational resources,thus they can provide better quality of service for blockchain applications in different scenarios.Finally,security analysis demonstrates the robustness of ERSCP and ERACH.Experimental results show that ERSCP and ERACH have better performance in terms of transaction latency and throughput compared to existing consensus algorithms.