On November 4th, as the nation prepared to elect its new president, a parallel test of electoral integrity was taking place within CSAIL. A new open source voting technology, known as Scantegrity II, has been developed by an international consortium of researchers, which includes CSAIL Professor Ron Rivest and graduate student Emily Shen.
The team of researchers has identified three major requirements for electoral integrity: that the votes are verifiably cast as intended, collected as cast, and counted as collected. Because of the need to protect ballot secrecy, current voting systems cannot offer voters a receipt to prove that one’s vote has been collected as cast. Furthermore, there are no guarantees that the votes have been counted as collected. The Scantegrity II system seeks to address these requirements and gives voters a clear and easy way to verify that their votes are counted correctly, and a way to contest an incorrect registration of one’s choice.
Cast as intended:
The Scantegrity II ballot is an optical scan ballot that the voter fills out with a special decoder pen, which activates invisible ink printed in the selected bubble to reveal a confirmation code. The confirmation codes, which are randomly generated and independent across ballots, can be written in a detachable bottom portion of the ballot. This serves as a receipt for the voter’s choice.
Collected as cast:
Once the results are tabulated, voters can verify that their confirmation codes are posted correctly on an election website. When a voter enters the serial number of her ballot onto the website, the confirmation codes for each of the voter’s choices are revealed. The actual choices themselves remain secret, eliminating the danger of vote buying.
Counted as collected:
Using an audit mechanism on the election website, anyone can verify that the collection of confirmation codes is properly translated into the collection of corresponding candidate choices, and that these choices are tallied correctly.
For more information on the Scantegrity project, please visit scantegrity.org.