Vote&Check: Secure Postal Voting with Reduced Trust Assumptions

Vote&Check: Secure Postal Voting with Reduced Trust Assumptions. VÃ©ronique Cortier, Alexandre Debant, Pierrick Gaudry, and LÃ©o Louistisserand. In PETS 2025 - Privacy Enhancing Technologies Symposium, Washington, DC, USA, 2025.

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Abstract

Postal voting is a frequently used alternative to on-site voting. Traditionally, its security relies on organizational measures, and voters have to trust many entities. In the recent years, several schemes have been proposed to add verifiability properties to postal voting, while preserving vote privacy. Postal voting comes with specific constraints. We conduct a systematic analysis of this setting and we identify a list of generic attacks, highlighting that some attacks seem unavoidable. This study is applied to existing systems of the literature. We then propose \VC, a postal voting protocol which provides a high level of security, with a reduced number of authorities. Furthermore, it requires only basic cryptographic primitives, namely hash functions and signatures. The security properties are proven in a symbolic model, with the help of the ProVerif tool.

BibTeX

@inproceedings{VoteCheck-PETS25,
      author = {VÃ©ronique Cortier and Alexandre Debant and Pierrick Gaudry and LÃ©o Louistisserand},
      title = {Vote&Check: Secure Postal Voting with Reduced Trust Assumptions},
      booktitle = {PETS 2025 - Privacy Enhancing Technologies Symposium},
      year = {2025},
      abstract = {    Postal voting is a frequently used alternative to on-site voting.
    Traditionally, its security relies on organizational measures, and
    voters have to trust many entities.
    In the recent years, several schemes have been proposed to add
    verifiability properties to postal voting, while preserving vote privacy.
    Postal voting comes with specific constraints. 
    We conduct a systematic analysis of this setting and we identify a
    list of generic attacks, highlighting that
    some attacks seem unavoidable. This study is applied to existing
    systems of the literature.
    We then propose \VC, a postal voting protocol which provides a high level
    of security, with a reduced number of authorities. Furthermore, it requires
    only basic cryptographic primitives, namely hash functions and signatures.
    The security properties are proven in a symbolic model, with the
    help of the ProVerif tool.},
      address = {Washington, DC, USA},
}