[EM] My "bible meeting" attack on Rivest, saga continues...

[Warren Smith]

Yes, Ka-Ping Yee is right my new attack on
Rivest scheme can be argued not "really" to be an attack because
(a) it is a 3-way collusion (voters, vote-buyers, and govt)
 and my Rivest description only claimed it to be secure against ONE
 of these players, not all 3 in collusion,
and
(b) those voters gave up their receipts, like driving without seatbelt on, so
 why should it work anymore?

However, I feel that
(1) THIS collusion happens to be pretty likely-sounding,
 whereas the usual point with large collusions is they are supposed to be unlikely.
(2) It doesn't actually feel like a large collusion since while millions could be involved,
 only a few need to be in on the secret and the rest could be entirely innocent,
 or at least could justifiably claim they were.  I mean, it is like you give a bank robber
 driving directions to a bank that you dislike, whie having little or no certainty it
 was a bank robber.  Is that a "collusion"?
(3) When you leave off your seatbelt, you know you are taking a risk.  When you
 give up your receipt to an organization on your side, you know you
 are being protected, and indeed (with the fraud scheme) in fact over-protected (you
 will be miraculously granted 3 votes instead of just 1).  So that analogy doesn't
 make me happy.
(4) Sure this would be out-and-out fraud, but the whole damn point of Rivestism, was
 it was supposed to PROTECT us against fraud (assure it would be detected, anyhow).
 If it does not, as here, then it failed.

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Next, Juho Laatu's idea sounds a lot more promising:
>The voting machine could make some additional copies of the receipts
>and distribute them to other voters. Then voters could not be sure
>that they have the only copy of the receipt.

Aahh.  This, I like.   Let us say, 1% of all voters, randomly selected, are
"lucky voters" who get an extra receipt handed to them from somebody else's vote.

That is big protection against the attack I outlined.  However,
if the machine can do that, then it is risky the machine can remember stuff,
or risky the machine could permit the govt to see what got copied, both of
which would be bad and would enable cheating.

Still, this sounds like a least the beginning of an excellent idea
for saving Rivest's skin...

OK (variant): the machine (let us say) is dumping all the ballots random-order into a big bin.
Each voter rolls 2 dice, and if gets 6&6 is selected to be a lucky voter
who gets to pull a ballot out of the bin randomly and get a copy of it.
That way, no memory goes on, and randomness is self-evident.

Hey, *that* really does seem to fix it.

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You know, this whole development is just the weirdest experience.
Alice in Wonderland goes voting.  Lewis Carroll, you know, was a
prominent voting researcher.

--
Warren D. Smith
http://RangeVoting.org  <-- add your endorsement
and
math.temple.edu/~wds/homepage/works.html