| Bitcoin,as a virtual currency,and its underlying technology blockchain are being paid much attention to and studied by a large number of people.With the characteristics of data security and transparency,anti-tampering,peer-to-peer,decentralisation and traceability,blockchain applications are beginning to emerge in the world.The essence of blockchain is a kind of distributed database.The most important of a distributed database is how to ensure consistency and how to reach consensus among multiple nodes.Consensus mechanism is an algorithm to reach consensus on the order of a particular data and transaction within a period of time.Consensus mechanism is the soul of blockchain and one of the current research hotspots.Numerous consensus mechanisms have emerged one after another for different application of blockchain projects and performance requirements of algorithms,and the development of blockchain cannot be separated from the continuous exploration and improvement of consensus algorithms.The proof of work consensus used in blockchain has been criticized for its low efficiency and certain consumption of power and arithmetic resources;the practical Byzantine faulttolerant algorithm in the classical distributed algorithm is only applicable to the consortium chain because of its performance bottleneck;many other consensus algorithms are basically combining and improving each other on the basis of these two algorithms,while relatively little research has been conducted on the consensus proof of authority used on the third-party platform of Ethernet.The consensus algorithms used on third-party platforms of Ethernet are relatively less studied.To this end,the paper proposes Verifiable Proof of Authority based on the Verifiable Random Function and the proof-of-authority consensus algorithms.The main research contents of this paper are as follows.(1)The problem that the remainder method for the leader node of the proof of authority consensus algorithm easily leads to the disclosure of the leader node and therefore is easily exposed and attacked.An improved scheme of the Verifiable Proof of Authority consensus algorithm(VPoA)based on the verifiable random function is proposed,which improves the leader node selection method,makes the selection of the leader node more random and hidden,and ensures the security of the authority node to meet the different business needs of the blockchain network.(2)In the proof-of-authority algorithm,the leader node needs to propose and confirm the block,but the selection of the leader node is generally predetermined by the system and cannot be changed.In order to improve the decentralisation of this algorithm,a dynamic change scheme of the authority node based on credit mechanism is proposed,thus the state change of the node can be achieved.If the authority node is evil,it will become an ordinary node or even be removed,and the ordinary node can become a new authority node even if it gets half of the votes of the authority node,which improves the security and participateability of the system.(3)Finally,we implement the VPoA and conduct the leader node selection and consensus process of the VPoA algorithm experiments,study the two main implementation of PoA algorithms,Aura and Clique.After comparing the three algorithms,the experiments show that VPoA has better block generating time and better performance.The improved algorithm was tested on a test chain built on Kovan,a three-party platform for ethernet,and the security analysis showed that the improvement worked properly,retaining the benefits of the PoA algorithm and improving the system’s accessibility. |
