The Venezuelan system does have a voter-verified paper trail:
The voter then goes into the voting booth. He pushes an electronic keyboard that brings up the picture of his candidate on a touch screen monitor. The screen then asks if it has the picture of the candidate he selected. When the voter pushes the yes button on the screen, he receives a paper ballot. He then takes the paper ballot, leaves the machine and puts it in a cardboard box. The electronic tally is on each machine. The tally is also transmitted over the Internet to a central place.
After he puts the ballot in the box, he goes to another desk where he puts his little finger in indelible ink to make sure he can be detected if he tries to vote again.
The paper ballot has printed material that does three things. First, it includes a code to make sure that paper ballot box hasn't been manipulated. Second, it tells the voter he has voted. Third, it indicates who he has voted for. It doesn't indicate who the voter is.
When polls close, that paper tally for that one machine is correlated against all the paper ballots put in a cardboard box by everyone at the polling place. Although statisticians say a 3% audit is more than sufficient, the Venezuelan Council went further: 54.3% of the machines, arbitrarily selected, have their tallies audited by comparing the paper ballots with the electronic tally.
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