Comment by Thlom

You don’t, but you can validate the system as a whole. If you wish you can show up in the morning, confirm the ballot box is empty, look at the ballot box all day, follow the box out back and observe the ballots are poured onto a table, sorted in stacks and counted first electronically and then manually and see that the result is the same that shows up in the official tally. Validating that my single vote is counted correctly is worthless if the result is manipulated on the backend and it’s much harder (impossible) for any regular Joe to validate that an entire cryptographically secure voting system doesn’t manipulate the count somewhere.