Edge work: Using quantum mechanics to protect our privacy
Why? It will make electronic communications more secure.
Where? Université de Montréal
Initial response: “Very few people took it seriously.”
Privacy wonks should love Gilles Brassard. He is the guy who has delivered their seemingly impossible desire: an absolutely confidential way to send electronic messages. Unfortunately, it involves quantum mechanics, the twilight zone of physics. Brassard, a 52-year-old professor of computer science at the Université de Montréal, turned the wild idea of using the quantum world to send messages electronically into something real. Soon it may be essential.
Quantum cryptography ensures complete privacy because any attempt to observe the transmission will change the message. It is a basic principle of quantum mechanics: The act of observing affects the thing observed. “If I send you information in the form of quantum signals and someone tries to eavesdrop on that signal,” Brassard explains, “the act of eavesdropping will disturb the signal. It will also alert the recipient if the transmission has been compromised.”
As a child Brassard wanted to be a mathematician, but he became fascinated with programming when he took a computer science course at the Université de Montréal, which he entered at age 13. A decade later, in 1979, he became fascinated with how the strange properties of quantum mechanics could be harnessed to send confidential messages without an elaborate encoded key, as required by conventional cryptography. In 1983 he codeveloped BB84, the first practical quantum cryptography scheme, and he continued to refine it for years.
Today, along with physicists like Christopher A. Fuchs of the Perimeter Institute for Theoretical Physics in Waterloo, Ontario, he is also reexamining the foundations of quantum mechanics to see where information fits in. Brassard suspects that underlying the fundamental laws of the universe are information theory axioms rather than waves or particles. “I don’t have any formal training as a physicist,” he says, “but sometimes that’s good. It helps you see things differently.”