Vote-Independence: A Powerful Privacy Notion for Voting Protocols

Jannik Dreier (1) , Pascal Lafourcade (2) , Yassine Lakhnech (3)

1 CASSIS - Combination of approaches to the security of infinite states systems
2 LIMOS - Laboratoire d'Informatique, de Modélisation et d'optimisation des Systèmes
3 VERIMAG - IMAG - VERIMAG

Recently an attack on ballot privacy in Helios has been discovered [20], which is essentially based on copying other voter's votes. To capture this and similar attacks, we extend the classical threat model and introduce a new security notion for voting protocols: Vote-Independence. We give a formal definition and analyze its relationship to established privacy properties such as Vote-Privacy, Receipt-Freeness and Coercion-Resistance. In particular we show that even Coercion-Resistant protocols do not necessarily ensure Vote-Independence.

Mots clés: Privacy; Anonymity; Electronic Voting; Security; Formal Verification; Coercion-Resistance; Receipt-Freeness

Domaines: Cryptographie et sécurité [cs.CR]

Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech. Vote-Independence: A Powerful Privacy Notion for Voting Protocols. 4th Canada-France MITACS Workshop on Foundations & Practice of Security (FPS'11), May 2011, Paris, France. ⟨10.1007/978-3-642-27901-0_13⟩. ⟨hal-01338070⟩