Today: Security of voting systems, Monday, April 27th

Interesting application of cryptography. Challenging primarily because of the need for a secret ballot (how individual people voted).

Voting is not just about producing an answer, but also evidence that the answer is correct: convince losers that they lost fair and square.

Voting tech survey

Questions to ask of every voting system:

Retail fraud vs. wholesale fraud

Voting requirements

Security threats




Software independence (SI): a voting system is software dependent if an undetected error in the software can cause an undetectable change in the reported election outcome

New voting system proposals: "end to end"


VVPAT only gets the first: once ballot is cast, "chain of custody" determines what happens

Twin (Rivest and Smith)

Twin has all the "end-to-end" properties.

Scantegrity II (Chaum et al)