Research And Application Of Proof Of Authority Consensus Mechanism On Blockchain

With the continuous advancement of blockchain technology,consensus algorithms have become a core focus of attention.Among these algorithms,Proof of Authority(PoA)consensus mechanism has gained widespread application due to its resource-friendly features.It relies on authority nodes to generate blocks and adopts the longest-chain rule to reach consensus.However,due to the fact that only one block is appended to the blockchain in each round,the PoA mechanism suffers from performance,security,and decentralization issues.To address these shortcomings,this thesis conducts research on PoA mechanism in terms of performance security and decentralization,investigates the reasons behind these issues,and proposes specific solutions.The main contributions of this thesis are as follows:1.This thesis proposes Proof of Authority based on multi-node concurrent block generation(CoPoA).CoPoA enables all authority nodes to generate different types of blocks concurrently,making full use of each authority node’s resources.It also expands the single-chain structure of the original PoA to multiple parallel-chain structures,enabling each node to store more blockchain information and enhance performance.In addition,CoPoA designs a random beacon protocol and integrates it into the leader selection process,which can prevent an adversary from targeting the authority nodes.This thesis makes a theoretical analysis of CoPoA and demonstrates its performance through a prototype implementation and multiple tests.The experimental results indicate that CoPoA achieves 2x throughput improvement and 5x latency reduction compared to the original PoA protocol.2.This thesis proposes Proof of Authority based on a dynamic set of blockgenerating nodes(DyPoA).DyPoA decouples the right of generating and committing block to the blockchain owned by authority node in the original PoA.It enables the common nodes to perform the process of packing transactions into blocks,while authority nodes validate and commit blocks to the blockchain.Additionally,DyPoA desgins a contribution score mechanism to measure the work accomplished by each node in the network when a block is appended to the blockchain.Moreover,DyPoA selects some common nodes to participate in the process of validating and committing blocks to the blockchain based on the contribution score of each node.This thesis conducts a security analysis of DyPoA and demonstrates its degree of decentralization and availability of DyPoA through dencentralization metrics and performance tests.The experiment results show that the Shannon entropy,Gini coefficient and Nakamoto coefficient of DyPoA are1.5 times,0.7 times and 1.7 times of the original PoA,respectively,and achieves 2.2x throughput improvement and 3x latency reduction compared to the original PoA protocol.3.To solve the problems of news dissemination,this thesis proposes a News Consortium Chain Management System,which utilizes a combination of CoPoA and DyPoA consensus algorithms.The system adopts CoPoA and DyPoA to realize the function of adding news to the blockchain and maintaining the blockchain network decentralized.It also provides a user-friendly visual interface for ease of use.In order to prove the availability of the improved PoA algorithms,the system is implemented and tested in this thesis.