There’s a good article that came out this week in Technology Review, which provides and approachable discussion of the “scratch-and-vote” method developed by MIT VTP colleagues Ron Rivest and Ben Adida. Here’s a short snip from the article describing the method:
The S&V approach makes this auditing process secure because it allows a ballot paper to be checked without having to involve an election official (who in theory could be corrupt and tamper with a ballot). When applied to the Prêt-à-Voter scheme, S&V adds a scratch surface on the side bearing the candidates’ names, while the order of the candidates’ names is encoded cryptographically beneath the tick boxes. “This scratch surface is exactly like a lottery card,” says Adida.
To check that a ballot paper hasn’t been rigged, the voter simply scratches off the surface to reveal a number that can be combined with a number corresponding to the order of the names and a publicly available encryption key. In theory, voters could use cryptographic software at the poll to perform these operations; but in practice, trusted third-party organizations could provide a means for voters to check their ballot papers. If the codes match, the “audit” ballot is legitimate, and it should be okay to vote with the other ballot.
It’s exciting to see research and development efforts like these, because they do represent the future of voting technology. However, as Michael Shamos points out towards the end of the Technology Review article, the trick will be to get public and political acceptance of these novel approaches to balloting.