Punchscan is an optical scan voting system invented by David Chaum that allows voters to take a piece of the ballot home with them as a receipt. This receipt does not allow voters to prove how they voted to others, but it does permit them to:
- Verify that they have properly indicated their votes to election officials (cast-as-intended)
- Verify with extremely high assurance that all votes were counted properly (counted-as-cast).
More here Punchscan.org
I saw the demo video and am impressed. This is a really good method of solving all the major issues in voting. Pre-vote tamper proof, verifiable and post-vote tamper proof. My big complaint about paper receipts is that it could be used by fanatical pastors, union bosses or other unethical individuals to enforce a voting agenda on subordinates.