An unlinkably divisible and intention attachable ticket scheme for runoff elections

Abstract

In a runoff election, the second round of voting must be performed to elect an absolute-majority winner when no candidate receives more than 50% of the votes in the first round of voting. Many states, such as France, Portugal, and Russia, have adopted this type of voting systems to elect their Presidents. In this paper, an unlinkably divisible and intention attachable ticket scheme is designed for runoff elections. A ticket in our scheme is composed of a main vote and a spare vote. The main vote containing some voter's intention can be extracted from the ticket for the first round of voting. If the second round of voting is required, the tally center enables the spare votes such that each voter can derive a spare vote from his ticket. A voter can then attach his intention to his spare vote for the second round of voting and, especially, the spare vote cannot be linked to the main vote by the tally center.