Amun: Securing E-Voting Against Over-the-Shoulder Coercion

Riccardo Longo; Chiara Spadafora

Paper 2021/851

Amun: Securing E-Voting Against Over-the-Shoulder Coercion

Riccardo Longo

, Fondazione Bruno Kessler, Center for Cyber Security

Chiara Spadafora

, University of Trento

Abstract

In an election where each voter may express $P$ preferences among $M$ possible choices, the Amun protocol allows to secure vote casting against over-the-shoulder adversaries, retaining privacy, fairness, end-to-end verifiability, and correctness. Before the election, each voter receives a ballot containing valid and decoy tokens: only valid tokens contribute in the final tally, but they remain indistinguishable from the decoys. Since the voter is the only one who knows which tokens are valid (without being able to prove it to a coercer), over-the-shoulder attacks are thwarted. We prove the security of the construction under the standard Decisional Diffie Hellman assumption in the random oracle model.

Metadata

Available format(s): PDF
Category: Cryptographic protocols
Publication info: Published elsewhere. Minor revision. SECRYPT 2024
DOI: 10.5220/0012786800003767
Keywords: E-Voting Over-the-Shoulder Attack End-to-End Verifiability Diffie-Hellman Assumption Formal Proof of Security
Contact author(s): rlongo @ fbk eu
chiara spadafora @ unitn it
History: 2024-11-05: last of 4 revisions; 2021-06-22: received; See all versions
Short URL: https://ia.cr/2021/851
License: CC BY

BibTeX

@misc{cryptoeprint:2021/851,
      author = {Riccardo Longo and Chiara Spadafora},
      title = {Amun: Securing E-Voting Against Over-the-Shoulder Coercion},
      howpublished = {Cryptology {ePrint} Archive, Paper 2021/851},
      year = {2021},
      doi = {10.5220/0012786800003767},
      url = {https://eprint.iacr.org/2021/851}
}