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Opinion: Just last month, Australian researchers made a global breakthrough in portable quantum cryptography. Read the first-hand account from the NSW Defence Innovation Network’s Lincoln Parker.
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In September of 2017, the Chinese Academy of Sciences prepared and carried out the world’s first secure intercontinental “quantum call” over a record distance of 7,600 kilometres between Beijing and Vienna.
The secure quantum call lasted 75 minutes and demonstrated China’s lead in quantum physics with the potential for a hack-proof quantum internet being developed and adopted, with Chinese characteristics, of course.
Over five years later and no other country in the world has been able to demonstrate such a capability.
Unhackable
Which is why last month’s demonstration in Sydney of an Australia-first (and in some respects, a world first) portable quantum cryptography system demonstrating a robust single photon source (SPS) based on impurities in hexagonal boron nitride (hBN) that act as single photon emitters, is so important.
I was lucky enough to attend with a room full of select invitees.
As Australians well know and have recently become accustomed to, communication security is becoming ever more perilous and therefore important. Communication security is also one of the biggest challenges in modern warfare. Our adversaries have mastered the art of hacking, eavesdropping, attacking and stealing.
This is why the future of communications technology is shifting towards quantum-based telecommunications. Single-photon sources are the perfect information carriers because they cannot be “copied” without detection, providing unconditional security.
Who done it?
About three years ago, the Defence Innovation Network (DIN) put out a call for a secure quantum communications project across our university network with the outstanding winning bid being accepted and funded. Due to security concerns, and to try and prevent the researchers and universities coming under attack themselves, I cannot name them or the collaborating universities. What I can say is that the project lead is a recognised leader in the field of solid state single photon sources, with over a decade of experience in engineering and characterising materials that host single photon emitters.
He (that narrows it down) is a professor at one of DIN’s eight-member universities. Let’s call him Professor X.
Under the hood
Professor X explained that the hBN emitters are unique in that they are very bright (>MHz count rate), optically stable and robust, and can be driven deterministically (i.e. one photon per one excitation pulse). Critically, single photon sources based on hBN outperform all other deterministic counterparts (e.g. quantum dots) in terms of repetition rate, brightness and polarisability at room temperature. Moreover, the hBN host that encapsulates the emitters is extremely robust against chemical deterioration and space radiation, making it very suitable for defence applications.
“So, what quantum key distribution gives you is this live monitoring of the channel, meaning that as you communicate with whoever you want to communicate, if there is an eavesdropper, you can detect it live and then change your communication protocol,” he said.
Prototype demonstration – real world conditions
The aim of the DIN-funded project was to demonstrate the deterministic source that will then be used as the source of the secure key, meaning that instead of going through a stochastic or non-linear process, the capability provides an on demand single photon source. “So you click, you get a photon, you click again, you get a photon,” Professor X explained.
The demonstration delivered that source in real terms, “meaning that we don’t want to be in the lab in a dark room, but we want to build a box that can be portable, and you want to have an ability to exchange the sources. You want to have the ability to swap them and operate them at room temperature and in bad conditions”, he said.
No limits
The demonstration proved that the key was shared, it was absolutely secure and that the security was run continuously. In other words, Professor X explained, “as we encode and decode an image of 1,000 bits, we can generate this key continuously. It means that you’re not limited by the key length. We’re actually not limited to any number, which means that if you want to transmit a key and you want to have a key with 2,000 bits or 8,000 bits or as many as you want, we can do that and that also was demonstrated, so our key basically has an unlimited length”.
What’s next?
One word, funding.
And an important question: do we want this capability to be funded and developed in Australia?
So far, DIN proposed and funded this project and capability to demonstrated prototype. As Professor X said, “in two years with a small team, a very competent team, we went from nothing to a TRL 4/5 device that actually does what you want it to do. So from here to a really usable device that actually can be employed, maybe 3–5 years is possible.”
But as Professor X pointed out to me, the next steps need to be done in close coordination with the eventual end user to tailor it to their needs rather than make it all things to all people.
Will that end user be Australian?
Note: Lincoln Parker works for the NSW Defence Innovation Network (an initiative of the NSW Government and eight Australian universities). The author’s views are his own.
