Abstract

Coercion is one of the remaining issues on internet voting. Many developing
countries are prone to this problem due to lower income rate. In this study, a novel coercion-resistant protocol has been proposed that can be integrated with previously proposed e-voting systems. We call it nullification. We present it as a part of the VoteXX e-voting protocol that has been designed and implemented through this study.

Nullification gives the voter a strategic advantage over the coercer. The voter can share her keys with a trusted proxy, called a nullifier, for later flipping that vote. Integrity and ballot secrecy are provided simultaneously through the use of zero-knowledge proofs, specifically Σ-protocols. We show how our approach is different from (and potentially composable with) re-voting or panic password techniques that have been previously proposed in the academic literature.
Through designing this protocol, we solve several issues, design new Σ-protocols and protocols for the secure evaluation of basic logic functions like exclusive-or (xor) under encryption: True XOR and Online XOR have been proposed that improves the previously proposed Mix and Match protocol for secure multi-party computation of an arbitrary function under constrained input domain.