Paper 2025/2286 Original: eprint.iacr.org/2025/2286 ↗
Improving the Efficiency of zkSNARKs for Ballot Validity
Abstract
Homomorphic tallying in secure e-voting protocols enables privacy-preserving vote aggregation. For this approach, zero-knowledge proofs (ZKPs) for ensuring the validity of encrypted ballots are an essential component. While it has been common to construct tailored ZKPs for every kind of ballot and voting method at hand, recently Huber et al. demonstrated that also general-purpose ZKPs (GPZKPs), such as Groth16 zkSNARKs, are suited for checking ballot validity. Unlike tailored solutions, GPZKPs provide a unified, generic, and flexible framework for this task. In this work, we improve on the initial GPZKPs for ballot validity proposed by Huber et al. Specifically, we present several circuit-level optimizations that significantly reduce proving costs for exponential ElGamal-encrypted ballots. We provide an independent, ready-to-use Circom implementation along with concrete benchmarks, demonstrating substantial improvements in performance and practical usability over prior implementations.
Metadata
- Available format(s)
PDF- Category
- Implementation
- Publication info
- Preprint.
- History
- 2025-12-19: last updated
- 2025-12-19: published
- Short URL
- https://ia.cr/2025/2286
- License
- https://creativecommons.org/licenses/by/4.0/
BibTeX
@misc{cryptoeprint:2025/2286,
author = {Felix Röhr and Nicolas Huber and Ralf Küsters},
title = {Improving the Efficiency of zkSNARKs for Ballot Validity},
howpublished = {Cryptology {ePrint} Archive, Paper 2025/2286},
year = {2025},
url = {https://eprint.iacr.org/2025/2286}
}