International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Information-Theoretically Secure Voting Without an Honest Majority

Anne Broadbent
Alain Tapp
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Abstract: We present three voting protocols with unconditional privacy and information-theoretic correctness, without assuming any bound on the number of corrupt voters or voting authorities. All protocols have polynomial complexity and require private channels and a simultaneous broadcast channel. Our first protocol is a basic voting scheme which allows voters to interact in order to compute the tally. Privacy of the ballot is unconditional, but any voter can cause the protocol to fail, in which case information about the tally may nevertheless transpire. Our second protocol introduces voting authorities which allow the implementation of the first protocol, while reducing the interaction and limiting it to be only between voters and authorities and among the authorities themselves. The simultaneous broadcast is also limited to the authorities. As long as a single authority is honest, the privacy is unconditional, however, a single corrupt authority or a single corrupt voter can cause the protocol to fail. Our final protocol provides a safeguard against corrupt voters by enabling a verification technique to allow the authorities to revoke incorrect votes. We also discuss the implementation of a simultaneous broadcast channel with the use of temporary computational assumptions, yielding versions of our protocols achieving everlasting security.
  title={Information-Theoretically Secure Voting Without an Honest Majority},
  booktitle={IACR Eprint archive},
  keywords={foundations / multiparty computation, voting, information-theoretic security},
  note={To appear in Proceedings of the IAVoSS Workshop On Trustworthy Elections (WOTE 2008) 14041 received 11 Jun 2008},
  author={Anne Broadbent and Alain Tapp},