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, 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.

Domaines: Cryptographie et sécurité [cs.CR]

Jannik Dreier, Pascal Lafourcade, Yassine Lakhnech. Vote-Independence: A Powerful Privacy Notion for Voting Protocols. [Technical Report] VERIMAG UMR 5104, Université Grenoble Alpes, France. 2011. ⟨hal-01338071⟩