An efficient multi-receipt mechanism for uncoercible anonymous electronic voting

Despite well-known controversies surrounding electronic voting (e-voting), electronic voting systems are gradually replacing traditional paper-based ones in some developed countries. An anonymous e-voting system that can be used in elections with large electorates must meet various security requirements, such as anonymity, uncoercibility, tally correctness, completeness, unrecastability, verifiability, soundness, and honesty. In particular, the uncoercibility requirement is essential, since systems meeting this requirement can largely reduce the possibility of coercion and bribery in elections. If a voter obtains only one voting receipt in an electronic voting system, coercers or bribers can enforce the voter to show her/his voting receipt to identify whether the enforced voter followed their will or not. However, if a voter can obtain multiple receipts reflecting several possible intentions in an election, coercers cannot distinguish these receipts to decide how the voter actually voted. In this article, we analyze possible venues for successful coercion, and present ideas for developing an effective electronic voting protocol, allowing one to greatly reduce the chances of coercibility. This protocol is independent of the underlying cryptographic components, and it can be easily implemented in electronic voting systems. We use random oracle models to demonstrate that the proposed protocol possesses the necessary security features.