Breaking verifiability and vote privacy in CHVote

Véronique Cortier; Alexandre Debant; Pierrick Gaudry

Paper 2025/080

Breaking verifiability and vote privacy in CHVote

Véronique Cortier, Université de Lorraine, CNRS, Inria

Alexandre Debant, Université de Lorraine, CNRS, Inria

Pierrick Gaudry, Université de Lorraine, CNRS, Inria

Abstract

Abstract. CHVote is one of the two main electronic voting systems developed in the context of political elections in Switzerland, where the regulation requires a specific setting and specific trust assumptions. We show that actually, CHVote fails to achieve vote secrecy and individual verifiability (here, recorded-as-intended), as soon as one of the online components is dishonest, contradicting the security claims of CHVote. In total, we found 9 attacks or variants against CHVote, 2 of them being based on a bug in the reference implementation. We confirmed our findings through a proof-of-concept implementation of our attacks.

Metadata

Available format(s): PDF
Category: Applications
Publication info: Preprint.
Contact author(s): veronique cortier @ loria fr
alexandre debant @ inria fr
pierrick gaudry @ loria fr
History: 2025-01-20: approved; 2025-01-18: received; See all versions
Short URL: https://ia.cr/2025/080
License: CC BY

BibTeX

@misc{cryptoeprint:2025/080,
      author = {Véronique Cortier and Alexandre Debant and Pierrick Gaudry},
      title = {Breaking verifiability and vote privacy in {CHVote}},
      howpublished = {Cryptology {ePrint} Archive, Paper 2025/080},
      year = {2025},
      url = {https://eprint.iacr.org/2025/080}
}