[EM] Re: touch screen voting machines

[Rob Speer]

On Wed, Nov 12, 2003 at 11:58:01AM +1300, R.G.'Stumpy' Marsh wrote:
> I disagree. As far as auditing is concerned, I think this sort of mass
> near-random testing is ideal. Sure the vast majority may not check
> their votes, but enough people on all sides of the election would
> check to make systematic fraud nigh on certain to be detected.
> 
> The only problem I see is with privacy, particularly the
> afore-mentioned stand-over problem. One way to get around that would
> be to provide the option of creating false receipts as well as the
> real one. The false receipt would be identical to the real one in
> every respect, except that the fake one has a false random ID and a
> false checksum. 

Everyone gets this idea as a solution to vote coercion. But you (most
likely) can't have anonymity, verifiability, and freedom from coercion
at the same time.

(No, I haven't seen a proof of this, but I'd like to; it would be a sort
of "Arrow's Theorem" for voting mechanisms.)

The "fake votes" method breaks verifiability, because you have no way to
verify that YOUR vote was not marked as "fake". If there is such a way,
then the thug demanding your vote can verify the same thing.

-- 
Rob Speer