Breaking verifiability and vote privacy in CHVote

Breaking verifiability and vote privacy in CHVote. Véronique Cortier, Alexandre Debant, and Pierrick Gaudry. In Esorics 2025 - 30th European Symposium on Research in Computer Security, Toulouse, France, 2025.

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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.

BibTeX

@inproceedings{breakingCHVote-Esorics25,
      author = {V\'eronique Cortier and Alexandre Debant and Pierrick Gaudry},
      title = {Breaking verifiability and vote privacy in {CHVote}},
      booktitle = {Esorics 2025 - 30th European Symposium on Research in Computer Security},
      year = {2025},
      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.},
      address = {Toulouse, France},
      year = {2025},
}