Research On Hierarchical Anonymous Voting Scheme Based On Flexible Threshold Ring Signature

Voting is a common way in modern democratic society,involving politics,joint-stock enterprises,court decisions and other fields.Voting as a specific form of balloting,with only two candidates in pro and con.The final result will be reached if one party has more than half of the votes.Security issues have always been a bottleneck restricting the development of electronic voting.In voting scenarios,users pay great attention to the security requirements of the fairness,anonymity and verifiability of the voting process;in certain voting scenarios,users have different weights which is defined as hierarchical voting.Blockchain is a digital accounting technology with the characteristics of time stamp,openness and non-tamperability which satisfy the transparency and verifiability of voting.In order to realize the anonymity of voting,this thesis uses ring signature to hide the correspondence between voting content and the voter.A flexible threshold ring signature scheme is proposed in this thesis.Furthermore,a hierarchical mechanism is designed by generating virtual identities for voters;and then a hierarchical anonymous voting protocol is proposed,which solves common security problems in electronic voting systems.The specific work in this thesis is as follows:(1)A flexible threshold ring signature scheme in chronological order is proposed,which has two advantages for solving the update problem and chronological problem in practice.When the signature is updated from d-out-of-n to d+1-out-of-n,the old signature can be reused.This is called “Flexibility”.The d participating signers should be ranked in chronological order.The scheme is a nontrivial extension of Yuen et al.'s signature scheme and has three security properties: unforgeability,anonymity and chronological sorting.The scheme is proved without random oracles and is tested over the Intel Edison development platform simulating practical edge servers.(2)A hierarchical anonymous voting protocol based on the flexible threshold ring signature scheme is designed,which realizes the legitimacy,confidentiality,unforgeability,non-repeatability,updateability,verifiability and immutability of voting.It can be used in situations where the votes vary from voter to voter.And the smart contract is used to analyze and implement the main functions of the voting protocol.