[tantanel]

In Estonia they allow you to vote multiple times and only the latest vote counts. They even allow you to then go and vote in the booth which renders your e-vote invalid. I don’t know the internals of how they store the votes but I can’t think of a way to do this without the side effect of knowing who voted for whom.

[toast0]

If you do this with two systems, the e-vote could be encrypted to the second system, but submitted to the first system. During voting hours, the first system would collect the votes and apply the latest value wins rules. Then, once voting is complete, it sends the votes (without envelope information) to the second system to tally. In order to know who voted for whom, you need collusion between the systems.