The toughest part is ensuring anonymity and privacy while ensuring someone can only vote once, ensure the vote is legitimate, and accounted for. The only way I

The toughest part is ensuring anonymity and privacy while ensuring someone can only vote once, ensure the vote is legitimate, and accounted for. The only way I can see that is using a PKI-based ID to validate the ID of someone, but then how do you ensure that person can vote anonymously and only once?