OTTAWA — An Ottawa physicist has developed a way to generate random numbers, the key to encrypting data in ways that hackers can't figure out.

Ben Sussman builds quantum technologies at the National Research Council. He's tapping into the fact that at the tiny (or quantum) scale of photons and electrons, events don't follow our familiar ideas of cause and effect, and can happen in completely random ways.

To people who want to encrypt data, this is a potential source of randomly-chosen numbers that are used as a "key" to lock and unlock sensitive data — military transmissions, banking transactions, or your email.

The idea is that if no one knows how the key was created in the first place, hackers and code-breakers won't be able to figure out the secret and decode the messages.

Sussman's new method, involving pulses of laser light in an Ottawa lab, has the potential to create truly random numbers in large quantities, and fast.

"If you want to defeat an adversary who is trying to hack into your system, basically you need large quantities of random numbers," he said in an interview.

"This has the potential to scale to extraordinarily fast rates, which is becoming more and more important as information networks expand and there are higher data rate requirements."

Sussman's Ottawa lab uses a pulse of laser light that lasts a few trillionths of a second.

His team shines it at a diamond. The light goes in and comes out again, but along the way, it changes.

"This out-coming light is very, very special," Sussman says.

It is changed because it has interacted with quantum vacuum fluctuations, the microscopic flickering of the amount of energy in a point in space.

Normally, we can know what happens to objects in physics, at least on the scale of most objects big enough to see. Even dice aren't truly random. We usually don't know enough to predict how they will roll, but they are still governed by laws of motion.

But the interactions changing the light are different. "What quantum mechanics tells us is that it's against the laws of physics to know" exactly what happens, Sussman said.

What happens to the light is unknown — and unknowable. Sussman's lab can measure the pulses of laser light that emerge from this mysterious transformation, and the measurements are random in a way that nothing in our ordinary surroundings is.

Those measurements are his random numbers.

The NRC notes in an announcement of his work that "most current technologies depend on number sequences generated by computational algorithms that are actually deterministic — only giving the appearance of being random.

"As technologies depending upon random number sequences proliferate, the fact that the numbers are not really random becomes increasingly problematic."

Picking random numbers can even ensure that a lottery is fair.

Sussman adds that "a truly random number generator will provide impenetrable encryption for communications — be they military transmissions, secure banking, or online purchasing — that underpin the modern connected world."

Ottawa Citizen

tspears@ottawacitizen.com