Abstract conceptual image of spiralling random colours

From spy thrillers to laser beams: quantum encryption is coming

Publication date
Friday, 26 Jun 2020

2020: another day, another headline announcing a new data breach. Even though it’s only June, we’re already on track to see hacking records broken. In the first quarter of this year alone, 8.4 billion records were exposed1.

Worldwide, spending on cyber security is skyrocketing. But our current methods for safe-guarding information don’t protect us from the biggest security threat looming around the corner: the inevitable breakdown of all encryption systems with increased computing power.

To find a solution, ANU researchers are looking to the realm of quantum physics. And: laser beams.

It sounds like a crossover between the Marvel Cinematic Universe and a John le Carré spy thriller — except in this case, fact may be even stranger than fiction.

A brief history of quantum mechanics

Professor Ping Koy Lam, outside with autumn leaves

Professor Ping Koy Lam.

“Quantum mechanics is a probabilistic theory. When you look closely, randomness and noise are everywhere around us,” says Professor Ping Koy Lam from the ANU Research School of Physics, explaining what happens when you go beyond the scale of an atom and into the quantum realm.

“Even if you have an empty space that is totally dark, and totally devoid of matter, virtual particles would be spontaneously appearing and disappearing.”

According to the theory of quantum mechanics, the laws of nature start behaving very strangely at this scale. So strange that Einstein himself deemed them to be just plain “spooky”.

But Professor Lam is less interested in the “spooky” aspects of quantum mechanics and more interested in harnessing a measurable quantum phenomenon: randomness.

“One thing we do in our labs is create random numbers using a laser beam.”

Back in the U.S.S.R.

To understand why Professor Lam’s lasers are so important to cyber security, we first need to go back to the Cold War.

Back then, KGB spies used an encryption method developed in the early 1900s known as one-time pad, where a random string of numbers is used to shift the position of letters of the alphabet.

Two spies would get identical note pads, each with the same string of random numbers on the first page. After writing or reading an encoded message, you would destroy the list of random numbers.

“If another person intercepted the whole encrypted message, the message would just be a random shuffle of letters that didn’t mean anything,” says Professor Lam.

This type of encryption has a major benefit over other methods: if the random numbers are only used once, there is no mathematical way to decode the message.

Computer games

Scientists working in quantum optics lab.

Dr Syed Assad (furthest right) and his team working in the ANU Quantum Optics Lab. The colour pattern displayed on the computer, and at the top of this article, were generated by quantum fluctuations.

Apart from one-time pad, most of our other current encryption methods rely on mathematical complexity and the fact that “some mathematical functions are easier to solve going one way and harder to solve going the other way,” says Professor Lam.

But these methods are far from perfect.

“If you have a big enough computer you may, by chance, eventually break the code,” he says. “So modern encryption security is dependent on the amount of resources you have. And the organisations that are well resourced have an information advantage over organisations that are poorly resourced.”

On top of this, government and industry are counting down the days until the inevitable development of quantum computers which will be powerful enough to break current mathematical encryption even faster.

Old-school rules

One-time pad doesn’t rely on mathematical complexity. Professor Lam says this century-old technique can be applied to modern computing and is proven to be absolutely secure. Unless, of course, you have access to the original string of random numbers.

“Some organisations used to generate one-time pads,” he says. “They then took a physical copy of the random numbers, via someone handcuffed to a briefcase delivering them to a secure location.”

This is kind of cool, but obviously pretty inconvenient, and additionally, there are many ways to compromise this kind of information security protocol.

“What if the random numbers are duplicated? What if someone sells your random numbers?”

Beam me up

This is where Professor Lam’s laser beam comes in, proving that you don’t need a quantum computer to produce unbreakable encryption. But you do need some help from quantum mechanics.

Light could allow for truly random numbers to be sent across the globe by harnessing the peculiar behaviour of quantum particles such as the photons of a laser beam.

“If you turn on a laser beam, and if you measure it with high accuracy, you can record fluctuations in the brightness of light,” he says.

“What we do is encode random numbers on the beam of a laser light, and we send that laser light to a receiver.”

As this information is encrypted in the laser beam, nobody can intercept the message: if an eavesdropper disrupts the laser beam, the act will be revealed to both the sender and the receiver. The string of random numbers will subsequently be discarded from use.

“If you get quantum encryption working properly, you can only break the code if the laws of physics themselves are broken.

“So, if our understanding of the laws of physics is correct, we have an unbreakable code.”

It’s like, so random

Professor Lam and his colleagues are in the business of providing true randomness to those who need it most. Their spin-off company QuintessenceLabs, works with major corporations to provide ‘quantum enhanced cyber security’.

But the random nature of quantum mechanics isn’t just useful for quantum encryption.

“Computer modelling—including for economics, climate change, and meteorological forecasting—uses a lot of random numbers.”

You can generate random numbers using computer algorithms, but according to Professor Lam, these random numbers could be biased.

Professor Ping Koy Lam in the optics lab

“Our random numbers are based on a physical system that we are very confident is truly random.”

The University’s Quantum Optics Group share random numbers for free on their website. Since the site was online in 2012, it has received more than 300 million requests for random numbers worldwide.

It is often used by computer scientists and engineers in place of algorithmic-based random numbers. “They will rely on our laser system to guarantee them true randomness.”

It is this experience in harnessing quantum mechanics for real-world applications which makes ANU a recognised leader in quantum research, education and commercialisation.

“At ANU we have an excellent track record of translating our research into commercial applications through start-up companies.”

Welcome to the quantum age

From secure quantum communications, to enhanced medical imaging and precisely modelling the impacts of climate change; it’s easy to see how quantum mechanics will swiftly and vastly change life as we know it in the coming years.

According to a recent study conducted by CSIRO, Australia’s burgeoning quantum industry, alone, is expected to generate more than $4 billion a year in revenue and 16,000 jobs by 2040.

Professor Lam says that the ANU Master of Science in Quantum Technology is one of the world’s pioneering educational programs to prepare people for the future quantum workforce.

“At the Department of Quantum Science, our research contributions span from enhancing gravitational wave detection with LIGO, to quantum data storage.”

But why stop there.

“Why can’t we make all modern devices thinner or lighter? If we can do it, it means we have to rely on fewer and fewer atoms to function. Eventually, you will have to analyse the whole system on the atomic scale, which is where quantum mechanics comes in,” says Professor Lam.

“Quantum physics is teaching us what the ultimate limit to our technological capability is.”

And the good news is that you won’t need to handcuff yourself to a briefcase to get in on the ground floor of this technological revolution.

Trench coats, however, are optional. 


Beam me up! With an ANU Master of Science in Quantum Technology, you not only learn from the research experts. These experts also happen to be leaders in the quantum industry. Who knows, you might even end up becoming the next Steve Jobs or Bill Gates of quantum technology.

[1] https://selfkey.org/data-breaches-in-2019/

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