DAVINCI: A Decentralized Cryptographic Voting Protocol

Pau Escrich; Marta Bellés-Muñoz; Roger Baig; Jordi Piñana

Paper 2026/2282

DAVINCI: A Decentralized Cryptographic Voting Protocol

Pau Escrich, Polytechnic University of Catalonia, Vocdoni Association

Marta Bellés-Muñoz

, Pompeu Fabra University

Roger Baig, Polytechnic University of Catalonia

Jordi Piñana, Vocdoni Association

Abstract

We present DAVINCI, a decentralized end-to-end verifiable voting protocol with no trusted coordinator. The protocol is structured as a zero-knowledge (ZK) rollup: the election is a ZK-verified state machine in which every transition, from ballot submission to final tallying, is encoded as a circuit constraint, so that no actor can force the protocol into an invalid state without breaking the underlying proof system. A decentralized set of sequencers handles ballot validation and aggregation off-chain, while Ethereum serves as a public bulletin board and a data-availability layer via EIP-4844 blobs. For ballot secrecy, DAVINCI uses threshold ElGamal with distributed key generation; for receipt-freeness, sequencers re-encrypt ciphertexts before storing them, and voters may revote at any time. To make revoting effective against bribery and coercion, DAVINCI introduces silent revoting on every state update, sequencers also re-randomize a random subset of stored ballots, and we quantify how well this hides overwrites among routine refreshes. Our open-source implementation shows that DAVINCI supports large-scale elections with succinct on-chain verification and ballot proofs generated on commodity devices, under the honest-device assumption shared by several deployed verifiable-voting systems.

Metadata

Available format(s): PDF
Category: Cryptographic protocols
Publication info: Preprint.
Keywords: Cryptographic Voting End-to-End Verifiability Receipt-Freeness Zero-Knowledge Proofs Blockchain
Contact author(s): pau escrich @ upc edu
marta belles @ upf edu
roger baig @ upc edu
painan @ vocdoni org
History: 2026-10-03: approved; 2026-09-30: received; See all versions
Short URL: https://ia.cr/2026/2282
License: CC BY-SA

BibTeX

@misc{cryptoeprint:2026/2282,
      author = {Pau Escrich and Marta Bellés-Muñoz and Roger Baig and Jordi Piñana},
      title = {{DAVINCI}: A Decentralized Cryptographic Voting Protocol},
      howpublished = {Cryptology {ePrint} Archive, Paper 2026/2282},
      year = {2026},
      url = {https://eprint.iacr.org/2026/2282}
}