Supernerds given the ultimate honour!

Two brilliant supergeeks had their genius immortalised last week with the awarding of the 2025 Turing Award (and a tasty $1 million!) for their inventing quantum cryptography.

(Well played legends - the godfathers of quantum cryptography Charles Bennett and Gilles Brassard)

(first published on my substack where you can get #NerdNews, marvellous maths and general geekery)

Don’t let those two words 'quantum cryptography' scare you. This is an awesome story. I’ll walk you through it nice and slow.

 Step into the light, Charles Bennett and Gilles Brassard, the two people whose work helped create quantum information science and the first serious practical ideas behind quantum cryptography.

“They were there since before quantum computing was even a field.” Scott Aaronsen, University of Texas, Austin.

In plain English, they helped show how physics itself can be used to spot cyber eavesdroppers.

A new way of keeping safe.

Quantum cryptography is a fundamentally different approach to the way we normally lock things up online. Most of today’s encryption relies on maths problems that are so hard they’d take an absurdly long time to untangle.

You might have heard of the RSA algorithm. It’s built around taking a ridiculously large number – about 600 digits long – that is two huge prime numbers multiplied together, and saying “if you want to crack this code, split this monster back into those two primes.”

For even a super‑powerful modern computer to brute‑force all the possibilities would take longer than the age of the universe.

But a big enough quantum computer could, in theory, do the same job in hours.

Well quantum cryptography does something more secure and tbh more beautiful.  

Instead of saying, “Please don’t attack this code because the sums are nasty,” it says, “Go on then, try listening in. The laws of quantum physics will rat on you.”

That’s the genius of Bennett and Brassard’s BB84 idea. If someone intercepts the key exchange, they disturb the quantum states and leave fingerprints behind.

Slow down Adam, wtf’s a key exchange?

A key exchange is just the process where two parties agree on the secret code they’ll use to scramble and unscramble messages. The key itself is not the message. It’s the thing that locks and unlocks the message.

In the RSA example above, the secret key is essentially the two prime factors of that mega‑number.

The magic of quantum key exchange is that the key can be shared in a way that exposes snoops, because measuring the quantum states changes them. That is annoyingly brilliant.

Again Adam, slow down; “measuring the quantum states”?

Back in the 1980s, Charles Bennett and Gilles Brassard had a beautiful idea.

Instead of emailing numbers around, they used single photons – tiny packets of light – to carry the key, with each photon set to point in a certain direction.

If a baddie wants to steal the data, they first have to steal the key. In this setup, that means reading those photons as they zip past. But photons, being slippery little buggers at the quantum level, don’t like being stared at. The very act of measuring them can change them.

So later, when the two legit parties compare notes on a handful of photons, those changed ones will show up as wrong answers. They don’t need to catch the hacker in the act, because the act of snooping itself has already messed with the key they were trying to steal.

That’s the Bennett–Brassard magic.

I should point out that while we are not all using Bennett and Brassard’s quantum key trick on our phones just yet, their idea lit the fuse under a whole industry now racing to make our everyday encryption safe in a world with quantum computers.

It’s the initial idea, and the entire field it spawned, that see B&B win that Turing bling.

I’m happy for these geeks, but why should I care?

Because this is about whether your secrets stay secret in an increasingly digital world.

If you’re a bank, government, telecom, or anyone moving sensitive data around, the appeal is obvious. A higher level of security grounded in physics, not just difficult maths.

With quantum computers seemingly coming closer to fruition, we need new, robust protections for the systems that hold together modern life, from online banking to secure government communications.

“Quantum information science is now home to thousands of active researchers, but until the mid-1990s it was a small community whose insights were often dismissed by outsiders. Bennett and Brassard were among its most vocal early advocates.” Ben Brubaker, Quanta Magazine.

In fact the transition to post-quantum cryptography is already underway.

NIST guidance and industry planning are pushing organizations away from RSA and other legacy algorithms over the coming years, with a broad migration horizon around 2030 to 2035.

In other words: the cryptography we trust today is not being declared useless tomorrow, but its expiry date is now visible on the calendar.

Bloody well done Charles Bennett and Gilles Brassard.

Hey I'm now also on substack.