Research On Parallel Blockchain Consensus Protocol Based On Directed Acyclic Graph

Blockchain is a distributed storage technology that originated from Bitcoin,which came out in 2009,and has emerged rapidly in the following years.Advantages such as high availability have attracted wide attention from government departments,financial institutions,technology fields,and capital markets,and have broad application prospects in many important fields such as government affairs,finance,storage,and auditing.The development of blockchain technology has experienced version 1.0 of blockchain represented by Bitcoin and version 2.0 of blockchain represented by Ethereum,but in the following years of technical application and market performance,people found that blockchain The performance of the system has encountered a bottleneck in improving the performance of the system,which is mainly manifested in serious insufficient transaction throughput,very slow transaction confirmation,and wasted computing power.These factors limit the promotion and application of the blockchain system.The first two generations of blockchains based on one-way block linked lists work in serial mode,so that blocks cannot be executed concurrently.The new blockchain technology based on Directed Acyclic Graph(DAG)fundamentally changes the serial working mode of the traditional chain blockchain because of its high parallel characteristics,which can improve the efficiency of confirming transactions and generating blocks.The speed is expected to make the performance of the blockchain system break through the bottleneck.Therefore,the DAG blockchain has received more and more attention and research from academia and industry,and is considered by the industry as the possible evolution direction of the future blockchain version 3.0.This paper summarizes the development of three versions of blockchain technology,studies their characteristics,research status and typical applications,analyzes key technologies such as system model,data structure and consensus protocol;analyzes the limitations of blockchain systems properties,and various improvements.Then,aiming at the problems of low performance and waste of computing power of traditional blockchain,a blockchain based on directed acyclic graph(DAG)and its consensus protocol are proposed to provide the blockchain system in a decentralized environment.Parallel work mode.In this structure,each block is connected to the predecessor block through three pointers.The first pointer forms a puzzle chain with the blocks with more difficult proof of work(Po W)to provide the order of the blocks in the DAG.Consistency with distributed ledgers,thereby ensuring the decentralization and security of the system;through the longest chain principle and the most difficult chain principle,the consensus of the puzzle chain is reached.The second pointer links the respective blocks of different miners into a chain of miners so that transactions can be distributed to different miners.The third pointer points to unconfirmed blocks in the DAG,enhancing the connectivity between DAG blocks and extending the security of the puzzle chain to all blocks in the DAG.Without sacrificing security and decentralization,this solution makes full use of the computing resources of network nodes,improves the performance of the blockchain system,and reduces computing redundancy and computing power waste.After modeling and analysis,in a peer-to-peer network with 1,000 nodes,the transaction throughput reaches 950 transactions per second,and the proportion of wasted performance is only 5%.Finally,the problems and challenges to be solved in the research of blockchain technology are pointed out,and further research directions are given.