About the Helios System
Helios is a cryptographically-verifiable voting system that enables voters to check the accuracy of the tally, rather than having to trust election administrators or equipment. A browser-based voting client written to an open specification is used to present options to the voter and to encrypt the voter's selections. The voter has the option to either submit the encrypted ballot or to "challenge" it to ensure that it is a proper encryption of the voter's selections.
Once an encrypted ballot is prepared, a voter can cast that ballot by presenting identification credentials. Challenged ballots can be posted as well. Once the election closes, the (threshold encrypted) ballots which have been properly cast by qualified voters are homomorphically combined to form a single aggregate encrypted ballot that represents the sum of the original ballots. The election trustees then use their respective decryption keys to open the resulting aggregate ballot and reveal the election tally. The correctness of the aggregation, the aggregate ballot decryption, and the decryption of any posted challenge ballots can be verified by one or more independent applications written to an open specification.
More information about Helios - including a paper describing its recent use in electing the president of UCL in Belgium - can be found at http://heliosvoting.org .