> With validation you could see people literally buying votes.

I think this is an area where you don't need a technological solution, just a legal one.

Vote selling/buying just needs to be as illegal as blackmail, fraud, etc. Fines and jail terms. (As I assume it already is?)

The thing is, it's going to be incredibly easy to catch, because if you're attempting to pay a group of people (employees, villagers, whatever) to sway their vote, there's always going to be at least one person who doesn't want to and inform the law. (Or else you don't need to be paying in the first place.) Hell, set up punitive damages so a whisteblower is guaranteed 50x whatever price they were being offered for their vote.