A Voting Scheme Based on Revised-SVRM and Confirmation Numbers

Abstract

This thesis improves the performance of the revised-simplified verifiable re-encryption mixnet (R-SVRM) based e-voting scheme by introducing confirmation numbers (𝐶𝑁s) that are used in the 𝐶𝑁 based e-voting scheme. Although 𝐶𝑁 based and R-SVRM based schemes had made e-voting schemes more practical by excluding zero knowledge proof (ZKP) that requires large volume of computations, still they are not efficient enough. Namely, the 𝐶𝑁 based scheme adopts RSA encryption functions that are not probabilistic or commutative, therefore to satisfy essential requirements of elections, extra random factors are necessary for individual votes, election authorities must sign on votes and they must keep encryption keys as their secrets. On the other hand, although the R-SVRM based scheme uses ElGamal encryption functions that are probabilistic and commutative, vote forms in it is complicated, i.e. vote forms consist of at least 3 items and they include information about candidates as exponents. The improved scheme simplifies vote forms by exploiting 𝐶𝑁s, and extensively reduces the number of operations required for individual votes. Also, the scheme successfully satisfies all essential requirements of e-voting systems, i.e. it is endowed with features about privacy, robustness, accuracy, incoercibility and fairness as 𝐶𝑁 based and RSVRM based schemes are.