English

Sophisticated Attacks on Decoy Ballots: The Devil's Menu and the Market for Lemons

Computer Science and Game Theory 2017-12-18 v1

Abstract

Decoy ballots do not count in election outcomes, but otherwise they are indistinguishable from real ballots. By means of a game-theoretical model, we show that decoy ballots may not provide effective protection against a malevolent adversary trying to buy real ballots. If the citizenry is divided into subgroups (or districts), the adversary can construct a so-called "Devil's Menu" consisting of several prices. In equilibrium, the adversary can buy the real ballots of any strict subset of districts at a price corresponding to the willingness to sell on the part of the citizens holding such ballots. By contrast, decoy voters are trapped into selling their ballots at a low, or even negligible, price. Blowing up the adversary's budget by introducing decoy ballots may thus turn out to be futile. The Devil's Menu can also be applied to the well-known "Lemons Problem".

Keywords

Cite

@article{arxiv.1712.05477,
  title  = {Sophisticated Attacks on Decoy Ballots: The Devil's Menu and the Market for Lemons},
  author = {Hans Gersbach and Akaki Mamageishvili and Oriol Tejada},
  journal= {arXiv preprint arXiv:1712.05477},
  year   = {2017}
}