29 Oct 2007
Last week's Swiss national elections made history by using a quantum cryptography system to protect the results.
Quantum cryptography was used in a real-world application for the first time when the Swiss went to vote in their national elections last week. A quantum key distribution (QKD) system protected the dedicated line that transmitted the ballots to the counting station, guaranteeing the secrecy and security of the data.
"Integrity of the data is the issue, it is vital that the data can't be modified during their communication from the location at which the ballots are counted and registered in computers to where the data are stored," Nicolas Gisin, a professor at the University of Geneva, told optics.org.
Developed by id Quantique, an industrial spin-off from the University of Geneva, the quantum key distribution apparatus uses single photons to produce a binary code, or key, to encrypt information. The rules of quantum mechanics ensure that anyone intercepting the key is detected, which in turn provides highly secure transmission.
According to Gisin, the system will not change the way people vote. "People will still use paper ballots, which are all collected in a central ballot processing location where they are counted," he said. "The results are then continuously sent to a Geneva state-owned data center."
Existing telecommunication glass fibers will be used to transmit the results over a distance of about 4km. "The system integrates a QKD apparatus and a classical advanced encryption standard (AES) encryptor running at 1 Gbit/s," explained Gisin. "In this way, the encryption key used by the AES encryptor is provided and secured by the QKD and can be changed up to four times per second. The entire system is fully automated and transparent from the user point of view."
The system was delivered and installed in early September and has since been thoroughly tested by the Center for Information Technology for the state of Geneva. "This is a commercial product and has been tested numerous times by many potential customers," commented Gisin. "We will see that the data arrive at the receiving data center uncorrupted."
The ability to secure data in any public fiber-optic network lends itself well to any company with sensitive data such as banks and insurance companies. "For the University there is a huge motivation to work on the next generation of QKD systems," concluded Gisin.