Coercion-Resistant Cast-as-Intended Verifiability for Computationally Limited Voters

In this work, we investigate if two essential properties in electronic voting, coercion-resistance and cast-as-intended verifiability, can be jointly achieved in settings where voters are (very) limited from a computational point of view. This may be the case in elections where voters use a voting station or webpage to cast their votes but do not have specialized software or devices to perform complicated cryptographic operations (for instance, to verify zero-knowledge proofs or to generate one-way trapdoors). We provide a solution where the only things voters have to do are: remember and compare strings of numbers, on the one hand, and press a button at the appropriate moment, on the other hand. This button activates the participation of an online entity, which is trusted to choose a random nonce for each voter and to publish it only when that voter presses the button (and not before). The most expensive part of the verification is an OR proof of knowledge, which can be done by any (powerful enough) external verifier.