Improvement of the DPoS Consensus Mechanism in Blockchain Based on Vague Sets

United Nations security council resolutions are voted on by fifteen members of the security council. A resolution will be deemed to be adopted if more than nine of the member states adopt it and all five permanent members do not use the veto. The five permanent members can vote yes, no, and abstain against a resolution. The vague set can be explained intuitively with the voting model, indicating the three conditions for voting. Which are favor, against, and abstention. When the agent nodes were selected by the consensus mechanism of delegated proof of stake (DPoS), the voting node can only vote support instead of against and abstention, and there are no penalties for malicious nodes. Besides, there is no clear method to select the agent node if the votes obtained by the last agent node are the same as the votes cast by others. This article puts forward a kind of vague set to improve DPoS consensus mechanism. Just like how human elections are held, this method allows each node to vote for the agent node. This is a fair and effective way of selecting agent node when alternate nodes are of the same value, it improves the security and fairness of blockchain, reduces the probability that malicious nodes will be selected as agent nodes. We prove that the maximum probability of nodes after the vote of the fuzzy membership degree is 0.5. The feasibility and effectiveness of the improved consensus mechanism is verified by examples.