This article appears in the 2026 BetaKit Most Ambitious issue. Read more stories of the Canadian tech innovators strengthening our autonomy, security, and prosperity here.
In 1983, Gilles Brassard’s studies in quantum information yielded an important discovery, almost two decades before the first quantum computer was ever built. He and his colleague Charles H. Bennett couldn’t have foreseen just how crucial the breakthrough would become: a communication protocol theoretically unhackable even by the most powerful quantum computer.
Forty years later, the breadth of their work would win them computer science’s highest honour, the Turing Award (in the spirit of Most Ambitious, we’re happily breaking our own rules by including Brassard in this section, ed.). Brassard is honoured by the award because it was granted by his peers. That recognition gives his ideas reach, and more leverage—two things he’s been fighting for his entire career.
Brassard considers himself the quantum industry’s Cassandra. For decades, he’s shouted from the rooftops about a threat lurking under the surface. Somewhere in the world, a quantum computer will eventually—or might already—have the power to crack modern encryption.
Brassard insists that its emergence will be catastrophic. A substantially powerful quantum computer could reveal the internet’s secure browsing and communication data, culminating in a cyberexposure event known as Q-Day.
“For decades, I was giving talks all over the world telling people, ‘Hey, this is serious,’” Brassard said. “When quantum computers completely break the current infrastructure, we’ll be in very, very big trouble. Don’t wait until it happens.”
A failed mathematician
Brassard first fell in love with mathematics when his older brother taught him college-level content when he was still in grade school (the Turing winner still refers to himself as a “failed mathematician”). The prodigious kid enrolled at the Université de Montréal to pursue a math degree at just 13 years old.
When he made the switch to computer science, he wanted to pursue artificial intelligence. “But then I was seduced by a course on theoretical computer science, and I decided it was much more interesting because it’s closer to mathematics.”
He eventually went to Cornell University to complete his Ph.D. under the tutelage of 1986 Turing winner John Hopcroft; around roughly the same time, he met his Turing Award co-honouree, Bennett, at an international conference.
The past is gone, forget it. It’s not too late to save the future.
Gilles Brassard
Brassard and Bennett’s protocol, known as BB84 (named after its authors and the year it was published), proposed a secure way to communicate information through quantum systems—with no eavesdropping and no leakages. This was a large part of their later Turing Award win.
BB84 and protocols like it are a necessary safeguard against the power of quantum computers. In the 1990s, mathematician and collaborator Peter Shor’s algorithm proved that a quantum computer could effectively solve how the world encrypts its messages. Shor’s algorithm factors large integers (including prime numbers) much faster than classical algorithms. Since these numbers underpin much of modern public-key encryption, quantum computers threaten the security of the internet we surf, potentially exposing the world’s private browsing and communications data.
Brassard says this reality is not a matter of if, but when. And bad actors are already harvesting encrypted communications for storage so they can later decrypt that information when quantum computers can reveal it.
“The past is gone, forget it,” Brassard said. “It’s not too late to save the future.”
To do that, “we have to move away from the current infrastructure to something that’s more resistant to quantum computers.”
Sovereign states of being
For years, Brassard’s warnings have been largely shrugged off. But governments and industry are starting to take the threat to traditional encryption systems very seriously.
Today, versions of the BB84 algorithm are live in some quantum-communication networks around the world, using both landlines via fibre and free-space communication through satellites.
Though Brassard said that Canada is making inroads toward quantum-safe communications and is bolstered by a strong research community, it’s still behind other places in the world. China, for example, has built a hack-resistant quantum network and aims to launch a global quantum-communication service by 2027.
Building the infrastructure to enable quantum-safe communication to protect Canada’s data is akin to the nation-building construction of railways or highways, Brassard argued. “I think we’re on the right path,” he said.
To Brassard, the sovereignty aspect is crucial. Though he was deeply honoured by the Turing Award, he won’t attend the ceremony in San Francisco this June—he refuses to enter the US as long as “the little dictator” is in charge.
“Ever since [Trump] declared war on Canada, I’ve boycotted the United States in all possible means,” Brassard said. “I’m not setting foot in that country anymore for any purpose whatsoever, not even to get this award.”
“I think that everybody should pull out of the US…no matter how much profit they make. Every country in the world should just tell the bully, ‘[We’re] not playing with you anymore.’”
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Feature image courtesy Studio Wyse for BetaKit.