Page 363 - Towards Trustworthy Elections New Directions in Electronic Voting by Ed Gerck (auth.), David Chaum, Markus Jakobsson, Ronald L. Rivest, Peter Y. A. Ryan, Josh Benaloh, Miroslaw Kutylowski, Ben Adida ( (z-lib.org (1)

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Scratch, Click & Vote: E2E Voting over the Internet
Checking integrity of R table is performed just as before, as well as vote counting:
the number of × marks does not change, the number of votes is now the number of rows
of table R divided by 4k.
How do the masked ballot columns help to preserve anonymity? The key observation
is that the number of masked ballot columns of each kind is determined uniquely by
the election result. Therefore R table provides no additional information. So the Strauss’
attack and any other attack based on the particular choice of ballot columns fails.
The same technique may be applied to ThreeBallot scheme.
5Final Remarks
SC&V allows for secure and verifiable vote casting over the Internet with unconditional
integrity. Privacy is preserved with the assumption that both authorities do not collude.
A voter cannot prove how she voted unless vote-casting is physically supervised by
an adversary (it is not the case in Internet version of Punchscan [15]).
Online vote-selling is almost impossible. In order to buy a vote, a buyer needs to
obtain:
– the record of a voting session from the voter’s computer (the serial numbers of
ballot and coding card, and the voter’s choices),
– ballot and coding card used.

Even if the voter’s PC is infected by viruses, her choice remains secret. Moreover, any
attempt of modification of voter’s choice is detected with high probability.

References

1. Top-to-bottom review. top-to-bottom report conducted by Secretary of State Debra Bowen
of many of the voting systems certified for use in California (2007),
http://www.sos.ca.gov/elections/elections_vsr.htm
2. Chaum, D.: Punchscan (2005), http://www.punchscan.org
3. Chaum, D., Clarkson, M.R., Haber, S., Jakobsson, M., Popoveniuc, S., Zagórski, F.: Internet
voting as secure as polling-place voting (preprint)
4. Chaum, D., Essex, A., Carback, R., Clark, J., Popoveniuc, S., Rivest, R.L., Ryan, P.Y.A.,
Shen, E., Sherman, A.: Scantegrity ii: End-to-end voter-verifiable optical scan election sys-
tems using invisible ink confirmation codes. In: USENIX/ACCURATE EVT 2008 (2008)
5. Chaum, D., Essex, A., Carback, R., Clark, J., Popoveniuc, S., Sherman, A., Vora, P.: Scant-
egrity: End-to-end voter-verifiable optical- scan voting. IEEE Security and Privacy 6(3),
40–46 (2008)
6. Chaum, D., Ryan, P.Y.A., Schneider, S.: A practical voter-verifiable election scheme. In:
di Vimercati, S.d.C., Syverson, P.F., Gollmann, D. (eds.) ESORICS 2005. LNCS, vol. 3679,
pp. 118–139. Springer, Heidelberg (2005)
7. Cicho´ n, J., Kutyłowski, M., W˛eglorz, B.: Short ballot assumption and threeballot voting
protocol. In: Geffert, V., Karhumäki, J., Bertoni, A., Preneel, B., Návrat, P., Bieliková, M.
(eds.) SOFSEM 2008. LNCS, vol. 4910, pp. 585–598. Springer, Heidelberg (2008)
8. Flajolet, P., Sedgewick, R.: Analytic combinatorics (2008)