Towards Realising Post-Quantum Secure ElectionGuard

ElectionGuard is a toolkit used to enable end-to-end verification of elections. Since
ElectionGuard uses exponential ElGamal, it is vulnerable to later vote decryption when
faced with quantum adversaries. Therefore, to avoid influences on voter behaviour, a
post-quantum adaption of ElectionGuard is needed to make the toolkits usage secure for
the foreseeable future.
In this work, we present cryptographic components that can be used to construct a
post-quantum version of ElectionGuard. We use the homomorphic encryption scheme
BGV and the commitment scheme BDLOP in a lattice setting. Applying existing and
new zero knowledge proofs, we construct the elements needed to show that votes are
well-formed and later aggregated correctly. As a final step, we show how to verifiably
decrypt the resulting tally.
In this paper, we lay the foundation for realising post-quantum secure ElectionGuard.
We provide the components for post-quantum vote encryption, aggregation, tallying and
verifiable decryption. Our work can be extended by distributed key generation and the
components for end-to-end verification.