Blinded additively homomorphic encryption schemes for self-tallying voting

Abstract

In this paper, we propose a self-tallying election protocol based public key homomorphic encryption. The additive homomorphism allows a set of participants (voters) to publish an encrypted value (ballot) and to compute the encrypted sum of all these values based on their ciphertexts. Our scheme has the particularity that anyone can decrypt the sum, but only once all participants have contributed to its computation. More precisely, the sum can be decrypted at all times, but remains blinded until all participants have contributed their vote, which contains a share of the unblinding key. Additionally, we propose an adaptation of Helios in order to provide self-tallying.