You have a paper trail, it anonymous, and it's pretty easy to understand.
I guess if you modified the firmware on the scanner to disclose the vote counters continuously, and the worker at the end knew me by sight (the worker I showed my I'd to is on the other end of the room) you could find my vote. But you could also hide a camera in the booth, which is easier.
It is also easier to check whether there is a camera in the booth.
There is also the issue of voters selling their vote. It's pretty easy for them to wear a tracker that tells you when they were in the booth. On the other hand, with paper ballots, the buyer has no way to check the vote, since market ballots are null.
The second problem also isn't a problem, because the machine doesn't need to be right. The paper ballot is leading, the machine is just an indication. The ballots are still counted by hand afterwards using the normal process. That means that as long as citizens are able to review the manual counting, they don't need to know or care how the voting machine works.
And yes, that does probably negate 90% of the advantages of voting machines.
The machine can register what was vote was cast at 13:42. From there, the whole idea of anonymity disapears.
> The second problem also isn't a problem
The impossibility to have the second criterion is a problem because it prevents the first criterion from being verifiable by anyone.
The problem is impossible to solve if you want to respect the following requirements:
- No one can know who you voted for
- Anyone can oversee the process and understand why fraud can't happen
There simply is no way to prove voter anonymity with an electronic machine without enough technical knowledge to audit the system.