Definitions and Analysis of Quantum E-voting Protocols

TL;DR

This paper introduces formal security definitions for quantum e-voting protocols, systematically evaluates existing schemes, and identifies specific quantum attacks that compromise their security due to lack of formal models.

Contribution

It provides the first formal security framework for quantum e-voting and critically assesses previous protocols against these standards.

Findings

Existing quantum e-voting protocols lack formal security models.

Many protocols are vulnerable to specific quantum attacks.

Formal definitions reveal security claims are often unjustified.

Abstract

Recent advances indicate that quantum computers will soon be reality. Motivated by this ever more realistic threat for existing classical cryptographic protocols, researchers have developed several schemes to resist "quantum attacks". In particular, for electronic voting, several e-voting schemes relying on properties of quantum mechanics have been proposed. However, each of these proposals comes with a different and often not well-articulated corruption model, has different objectives, and is accompanied by security claims which are never formalized and are at best justified only against specific attacks. To address this, we propose the first formal security definitions for quantum e-voting protocols. With these at hand, we systematize and evaluate the security of previously-proposed quantum e-voting protocols; we examine the claims of these works concerning privacy, correctness and verifiability, and if they are correctly attributed to the proposed protocols. In all non-trivial cases, we identify specific quantum attacks that violate these properties. We argue that the cause of these failures lies in the absence of formal security models and references to the existing cryptographic literature.