offer new ways to ensure privacy and
secure audit trails.
Punchscan is described as a “vote capture system.” What it offers is a means for
counting encrypted OpScan ballots that are
auditable, secure, and private. The voter
can verify his or her vote, and it provides
for a transparent count. The system was
used successfully in a student election at
allows the computer program to decode the
order candidates appeared so the vote can
be computed accurately. The scanned ballot
is then kept by the voter as a receipt.
Since the order of letters is scrambled
separately on the top and bottom sheets,
neither one alone is enough to say how the
vote was cast. “You have an encrypted
receipt,” Essex explains.
So is it going to be possible to have totally electronic
voting that is PRIVATE when cast, TRANSPARENT
when counted, and RELIABLE when reported?
the University of Ottawa and subsequently
won the grand prize last year in the
VoComp University Voting Completion.
For an explanation of how Punchscan
works, David Chaum had me talk with
Aleks Essex, currently a doctoral candidate
at the University of Ottawa, who organized
the field trial there.
Essex explains that Punchscan voters are
handed a two-layer ballot and a bingo
dauber (one of those foam-tipped inking
devices used to mark the called numbers in
a bingo game). The process involves multiple-choice selection for candidates where
the A, B, C, D beside their names is printed
in random order. Beneath the names, holes
in the top layer show A, B, C, D printed on
the bottom one—again in random order.
Voters mark the letter for the chosen
candidate, and because the bingo dauber is
a bigger than the hole, both layers get
inked. The layers are ripped apart and one
is fed to the shredder and the other to the
scanner. A serial number on the ballot
After the election, the voter can go
online and look up the serial number to see
what Essex calls a “cartoon version” of the
scanned ballot to check against the receipt
so the voter can ensure the ballot was
recorded as marked.
There are other safeguards, and those
interested will want to check the Punchscan
site, but the system isn’t perfect.
Chaum and his team have since released
their work on Scantegrity, an updated system that addresses some of the issues that
were raised with Punchscan.
“Scantegrity was born out of the
Ottawa election,” explains Essex. “We
achieved what we wanted to, but how
could we make it better?” The team decided the bingo-daubers and two-page ballots
had to go.
Scantegrity uses a more traditional fill-in-the-bubble optical scan ballot with a
tear-off receipt that halves a bar code.
Voters can mark the tear-off portion with
the letters of the chosen candidates.