[Cryptography] practical verifiable systems -- forensic and otherwise, cheap and otherwise

[Jonathan Thornburg]

On Mon, Mar 02, 2015 at 01:09:57PM -0700, John Denker wrote:
> Here's another example dear to my heart:  Vote-counting
> equipment.  Consider a setup where each voter goes to
> the polling place, marks a paper ballot, and feeds it 
> into a scanner right there at the polling place.  At 
> the end of the day, the scanner prints a tape with 
> the tally for that polling place.  Then the tape, and
> a duplicate tape, and the original ballots are sent
> downtown.  I'm leaving out a lot of details, but if
> done right, this setup is vastly more secure than
> an all-paper scheme or an all-electronic scheme.

It seems to me that any system involving a scanner and software is
much *less* secure than an all-paper scheme (with humans counting the
ballots at the polling site after polling closes, watched by multiple
other humans from different parties) (multiple other humans have of
course also checked that the ballot boxes were empty at the start of
polling, and have watched the ballot boxes all day):
* scanner+software --> vulnerable to a variety of software attacks
                   --> a single software attack can potentially
                       compromise the count at every polling place
                       across the country
* all-paper + human watchers/counters
                   --> vulnerable to "up-the-sleeve" and other
                       "stage-magician" tricks
                   --> those attacks require a trained/skilled attacker
                       at the (each) polling place, and hence are very
                       hard to run -- and keep secret -- at a big enough
                       scale to affect national results

ciao,

-- 
-- "Jonathan Thornburg [remove -animal to reply]" <jthorn at astro.indiana-zebra.edu>
   Dept of Astronomy & IUCSS, Indiana University, Bloomington, Indiana, USA
   "There was of course no way of knowing whether you were being watched
    at any given moment.  How often, or on what system, the Thought Police
    plugged in on any individual wire was guesswork.  It was even conceivable
    that they watched everybody all the time."  -- George Orwell, "1984"