Research And Implement On Blockchain Consensus Mechanism Based On Credibility Assessment

With the popularity of Bitcoin all over the world,block chain technology as its underlying technology has attracted the attention of governments and giant enterprises.The system features of decentralization,non-tampering,traceability and dynamic flexibility of block chains make their application prospects in various financial fields very wide.Consensus algorithm is the engine and core of block chain,which determines the security,stability and performance of block chain.However,with the development of mathematics,cryptography and computer technology,power-based consensus algorithms will become more and more fragile,and the possibility of solving mathematical problems will become greater and greater.Moreover,the consensus algorithm based on arithmetic itself has some attacks,such as double attacks,lightning attacks and so on.To solve these problems,I propose a block chain consensus mechanism based on credibility assessment.This block chain node defines the strength of the node by the trust value determined by its performance on the whole block chain,rather than by its relatively fast and temporary absolute computing power.The research contents of this paper are as follows:(1).The block chain encryption principle is analyzed,and the principle and shortcomings of traditional consensus algorithm are analyzed.A new consensus mechanism is proposed,which combines POW consensus algorithm,random function and consensus group methods.This method can ensure the electoral timeliness,at the same time,it can increase the difficulty of elections,and increase the cost of attack.Consensus groups are generated randomly and dynamically according to the ranking of trust values.Election among them can ensure that leaders have good credit.(2).For power-based attacks,this consensus mechanism creates a set of trust evaluation algorithms.The final trust value of the node consists of internal trust value and external trust value weighted.The internal trust value examines the contribution and regularity of the node's work,and the external trust value includes the transaction with others.Through the evaluation of these three aspects,the trust value of the node is established.This evaluation method will not only increase the difficulty of the attacker's attack,but also increase the time of the attacker.Moreover,when the node deviates from the system regulations and produces negative behavior,the system can reduce its trust value and make it unable to attack the system.Other POW-based systems punish them only by revoking the rewards of these nodes,and do not prevent them from attacking the system again.(3).Aiming at the problem that the efficiency and security of traditional consensus algorithms can not achieve a good balance,this paper proposes a consensus algorithm of multiple signatures,when consensus is reached between the selected leaders and consensus groups.Digital signature can ensure that the data is not tampered with,and can also verify the identity of the signer.The consensus method of "three handshakes" can ensure that leaders and consensus groups do not cheat alone.(4).Finally,the performance of the consensus mechanism is tested,and the security is analyzed.Compared with other block chain systems,it shows that the consensus mechanism not only resists power-based attacks,but also increases the cost of attacks and strengthens the security of block chain.