A Privacy Preserving and Format-Checkable E-voting Scheme.

Electronic voting (e-voting) is widely used because of its convenience and efficiency. In response to the security problems in e-voting, such as the legality of voters, privacy disclosure, etc., this paper proposes a novel e-voting scheme that can check the format of ballots without disclosing its content based on homomorphic encryption. Firstly, voters encrypt their ballots with Paillier encryption before sending them to the counter. Then, the counter decomposes the encrypted ballots using the proposed n-ary conversion protocol, and performs the format check of the ballots. Only ballots with the correct format are counted. During the whole process of voting, no one except the voter himself can know each ballot's content, even the counter, so that the privacy of ballots is preserved. Finally, the counter performs an additive homomorphism operation on the encrypted ballots and the voting manager decrypts it to tally the result. Besides the requirements including the legality, privacy, and integrity, we furtherly consider the validity of the ballots in e-voting and make the scheme more practical than the existing methods.