Blog: Computer Scientists Deploy First Practical Web-Based Secure, Verifiable Voting System

Computer Scientists Deploy First Practical Web-Based Secure, Verifiable Voting System
Harvard University School of Engineering and Applied Sciences (03/05/09) Rutter, Michael Patrick

The Harvard School of Engineering and Applied Sciences' Center for Research on Computation and Society (CRCS) and scientists at the University Catholique de Louvain in Belgium deployed a Web-based, secure, verifiable-voting system for the Belgium presidential election that was held in early March. Called Helios, the system was developed by CRCS fellow Ben Adida. "Helios allows any participant to verify that their ballot was correctly captured, and any observer to verify that all captured ballots were correctly tallied," Adida says. "We call this open-audit voting because the complete auditing process is now available to any observer." The open source software uses advanced cryptographic techniques to maintain ballot secrecy while providing a mathematical proof that the election tally was correctly computed. Helios uses public-key homomorphic encryption, a method in which a public key is used to encrypt a message, or a vote. Homomorphic encryption allows messages to be combined while still encrypted, which works for counting votes, and requires multiple private keys to decrypt a message, which was the election tally. In an election, voters receive a tracking number for each of their votes, and each vote is encrypted with the election public key before leaving the voter's browser. Voters can then use their tracking numbers to verify that their ballot was correctly captured by the voting system, which publishes a list of all tracking numbers received before tallying. Finally, the voter, or any observer, can verify that the tracking numbers and votes were tallied appropriately. Adida says the encryption allows the entire verification process to take place without revealing the contents of each vote.

View Full Article