One way hash with secret salt would work. You enter a secret password as a salt and get a hash code from all your votes so you have a provable record your vote got counted that you can verify but no body can reverse to know it's you.
Then stick all the votes up on a server somewhere. Let us go and check our votes are in the list. We could then have informal verification and audits of the counts.
>you can't prove how you voted (i.e. so you can't sell your vote). //
I assumed that if anything it was to prevent people being pressured in to voting a particular way (eg an abusive spouse) - what' wrong with selling your vote, surely that's still democratic: you've chosen to accept a particular candidate based on the outcome for you.
Vote buying is not about a voluntary market in a tradeable commodity - it is about your boss not being able to say 'prove you vote my way or I will sack you' or your landlord saying 'prove you vote may way or I will evict you'.
Nonsense. Existing laws protecting employees from employer retribution (e.g. for sexual orientation, or religion, or...) are still enforceable (and the judgments for plaintiffs are large, too).
There is no reason to prevent someone from verifying that their vote was counted -- not vote buying (or the presumed ease thereof), not vote tampering or stuffing (really?), not potential outside coercion of any kind. Laws exist for all of these things already, and would not suddenly become unenforceable or ineffective in the presence of vote verification.
Coercive voting has disappeared because it is impossible for the coercee to prove to the coercer that they complied.
My granny used to tell of tying red ribbons (red being for the left) on the goats in the country and her mother getting a lift to the polls from the Tories (when women first got the vote) and voting Labour.
Verifying your vote cannot relate to ballot stuffing at all - so you can prove to yourself that you voted X, but I have 1,000,000 made-up votes for Y.
But it would only be handed over to the highest bidder if the individuals chose to hand it over ... which is how democracy is supposed to work isnt it? Arguably the current system favours a cadre of the super-rich already. People now can vote for whichever party will make them individually richer. It just seems to me like a logical extension of capitalist economics.
Voters can sell their vote with or without a receipt. Furthermore, they can sell with a reasonable degree of certainty (if the buyer demanded it) already by submitting to a lie detector test.
There is no valid reason, moral or technical, for preventing voters from verifying their votes were accurately counted, and verification does not enable any new crimes – but it does prevent the current crime where someone's vote is either miscounted or not counted at all.
If voters are given a receipt, buyers of votes can demand to see said receipt to verify they voted the correct way. boss/abusive family member/mafia can demand to see the vote receipt on threat of your job/safety/family returning safely tonight. The potential for a vote receipt means that these 3rd parties can reward/punish you based on the way you voted. Without it, they have no way of knowing if their coercion/blackmail worked or not.
Personally, I would like to have a receipt because I think the danger of my vote not having been recorded is greater than the danger of someone demanding my vote receipt off me.
What is this mythical lie detector you speak of? No trustworthy lie detector exists. If you disagree: does yours work for all mental variations (psychopaths, autism, retardedness, ...) and physical variations (Down syndrome, a score of other genetic abnormalities, ...)? Have you actually verified the research or trust someone who did?
No lie detector exists that is effective to the standards we demand in a court of law, but that doesn't mean there isn't one effective enough for the purposes of an organized crime syndicate looking to buy votes.
Make the receipt optional for each voter. Assholes will still be assholes regardless of the existence of receipts. If someone is extorting you to vote a certain way, I doubt the outcome of an election will affect your life very much. You have bigger problems.