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How Quantum Cryptology Works

        Science | Everyday Myths

Votes cast in the Swiss canton of Geneva were protected for the first time by quantum cryptography.
Votes cast in the Swiss canton of Geneva were protected for the first time by quantum cryptography.
Fabrice Coffrini/AFP/Getty Images

The idea that a vote cast by a person remains the same after he submitted it is taken very seriously in any democracy. Voting is the right of the citizen, and it's how we choose the people who make important decisions on our behalf. When the security of the ballot is compromised, so, too, is the individual's right to choose his leaders.

There are plentiful examples of vote tampering throughout history in the United States and in other countries. Votes get lost, the dead manage to sho­w up on the poll results, and sometimes votes are even changed when they're tallied.

­But, hopefully, the days when paper ballots get lost on the back roads of Florida en route to be counted will soon be gone, and the hanging chad will become an obscure joke on sitcom reruns from the early 21st century. In other words, it's possible that the votes we cast will soon become much more secure.

One of the ways to safeguard votes is to limit access to them when they're being transferred from precincts to central polling stations where they're tallied. And this is just what the Swiss are looking into. The nation best known for its neutrality is on the cutting edge of research into quantum cryptography. But unlike traditional cryptology methods -- encoding and decoding information or messages -- quantum cryptology depends on physics, not mathematics.


U­sing a machine developed by Swiss manufacturer Id Quantique, votes cast in the Swiss canton of Geneva during the October 2007 parliamentary elections were transmitted using a secure encryption encoded by a key generated using photons -- tiny, massless packets of light. Since this method uses physics instead of math to create the key used to encrypt the data, there's little chance it can be cracked using mathematics. In other words, the votes cast by citizens in Geneva are more protected than ever.

Id Quantiques' quantum encryption is the first public use of such a technique. What's more, it has catapulted the little-known world of quantum cryptology onto the world stage. So how does it work? Since it's based on quantum physics -- the smallest level of matter science has been able to detect -- it can seem a little confusing. But don't worry, even quantum physicists find quantum physics incredibly perplexing.

In this article, we'll get to the bottom of how quantum encryption works, and how it differs from modern cryptology. But first, we'll look at the uses and the limitations of traditional cryptology methods.