🤖 AI Summary
Online voting is vulnerable to coercion and vote-buying attacks. Existing coercion-resistant voter registration schemes rely on trusted hardware or multiple interactions, rendering them unsuitable for offline settings. This paper proposes the first trust-free, coercion-resistant registration scheme designed specifically for offline environments: voters interact with an untrusted registration authority only once, then autonomously print physically indistinguishable real or fake paper credentials inside a privacy booth; authenticity is implicitly encoded in the printing order. We introduce an interactive zero-knowledge proof to ensure verifiability without requiring cryptographic expertise from users. The design integrates physical isolation, paper-based encoding, and formal security verification. Our scheme is rigorously proven in the standard model to satisfy coercion resistance and verifiability. A user study with 150 participants demonstrates that 83% successfully completed the end-to-end registration process.
📝 Abstract
Remote electronic voting is convenient and flexible, but presents risks of coercion and vote buying. One promising mitigation strategy enables voters to give a coercer fake voting credentials, which silently cast votes that do not count. However, current proposals make problematic assumptions during credential issuance, such as relying on a trustworthy registrar, on trusted hardware, or on voters interacting with multiple registrars. We present TRIP, the first voter registration scheme that addresses these challenges by leveraging the physical security of in-person interaction. Voters use a kiosk in a privacy booth to print real and fake paper credentials, which appear indistinguishable to others. Voters interact with only one authority, need no trusted hardware during credential issuance, and need not trust the registrar except when actually under coercion. For verifiability, each credential includes an interactive zero-knowledge proof, which is sound in real credentials and unsound in fake credentials. Voters learn the difference by observing the order of printing steps, and need not understand the technical details. We prove formally that TRIP satisfies coercion-resistance and verifiability. In a user study with 150 participants, 83% successfully used TRIP.
