And equally important, no one should be able to prove to someone else how they voted (because if they can prove it, coerced[1] voting could be a thing). "Secure voting" is a complicated beast, at the best of times.

[1] I am using "coerced" a bit loose here, I am including both "vote X, or else" as well as "if you vote X, I will give you this $SUM money". If it is by structure impossible to show that you complied, it is less likely that either will happen.