Design And Analysis Of A High Performance Public Blockchain Consensus Protocol

With the release of the white paper on bitcoin in 2008,blockchain technology has become hot.Bitcoin has solved the trust problem commonly existing in the Internet,and can conduct detrusting transactions without an authoritative center,which is a historic breakthrough.In the peer-to-peer network environment,blockchain constructs unforgeable,untamperable and traceable blockchain data structures in a specific order through transparent credible rules to promote the transaction processing mode between groups.It is a new application mode of computer technology such as distributed data storage,point-to-point transmission,consensus mechanism and encryption algorithm.It has been used in digital currency,financial services,supply chain technology,government governance,game services and other industries and has gradually become a research hotspot in academia and industry.Blockchains are usually divided into private chains,alliance chains and public chains.They have different focuses on decentralization,scalability and security.This paper focuses on the research of high-performance public chain consensus technology.The public chain usually runs in the unauthorized network environment,and the nodes are large.The traditional distributed algorithm is difficult to apply,and the probability consensus mechanism is more used.Research on public chain consensus technology usually focuses on improving its scalability as much as possible on the basis of ensuring certain decentralization and security.In view of the above research directions,the main contributions of this paper are summarized as follows :(1)For the research of Nakamoto consensus protocol,a public blockchain enhanced consensus protocol ORIC based on graph-chain account structure is proposed,which has the characteristics of decentralized,high bandwidth utilization,security provable and bandwidth adaptive.In the public blockchain environment characterized by free participation and full openness,the accounting efficiency of the Nakamoto consensus algorithm is far less than the requirements of current high-frequency transactions.At the same time,with the development of network technology,the available bandwidth of each node is generally improved,and the transaction efficiency of the Nakamoto protocol is still stable,which is also a waste of network resources.Therefore,this paper proposes a simple and efficient public blockchain consensus protocol based on graph-chain account structure,which draws on bitcoin core protocol and designs a special mining mechanism,allowing nodes to generate multiple blocks concurrently in one block-time,increasing the block generation rate so as to improve the maximum transaction throughput and bandwidth utilization.During the operation of the protocol,each high block is self-organized into a Directed Acyclic Graph(DAG)structure,and its sorting algorithm allows any honest node to obtain the same block sequence.Based on the existing theoretical results of bitcoin core protocol,the security and liveness of public ledger generated by the protocol are proved.The simulation results show that the bandwidth utilization rate is very high,and the protocol can also adaptively adjust the throughput to the theoretical optimum without sacrificing security when the available bandwidth of the node changes.(2)Aiming at the research of blockchain sharding technology,a sharding consensus protocol ORIC-Shard with partition sharing security and more scalability is proposed based on ORIC protocol.Most of the enhanced consensus protocols only focus on the scalability tips in terms of transaction efficiency.However,with the increase of transaction users and transaction frequency,the scalability problems in terms of state storage pressure,book storage pressure and calculation processing pressure of a single node will be highlighted.The sharding technology in the traditional database field is also applied to the blockchain system to alleviate the above problems.Therefore,this paper proposes a sharding improved protocol ORICShard based on ORIC protocol,which further improves the scalability.Through network sharding,transaction sharding and state sharding,the scheme significantly reduces the storage pressure and computing resource consumption of single node.Through the cross-sharding transaction model,the problem of transaction interoperability between shards is solved,and the final atomicity of cross-shard transactions is ensured.Through the reporting mechanism and error correction mechanism,the security of sharing the whole network computing power between the partitions is ensured without reducing the security of each partition due to sharding.The hybrid blockchain network topology model based on the combination of Gossip protocol and Kademila index technology accelerates the transaction-oriented broadcasting in shards and alleviates the problem of block message flooding.Through simulation experiments and theoretical analysis,ORIC-Shard compared with ORIC protocol,in a certain range,the storage pressure and computing pressure of nodes decrease linearly with the increase of the number of shards,and the transaction throughput is better.The innovation of this study is to propose a relatively complete consensus protocol for the main problems faced by the current public blockchain,which breaks through the problems from the underlying technology and provides the basis for the upper application.The research in this paper has positive significance for the future construction of new information infrastructure with blockchain,especially public blockchain as the core.