Is quantum communications technology the backbone of tomorrow’s digital economy?

Innovation in quantum key distribution is starting to enable a communications vision

Guy Matthews

It’s early days for real-world applications of quantum communications technology, with essential elements still very much in the trial phase or yet to be invented. But its future implications are already clear. It promises the secure movement of essential data, at scale and on a global basis, in a world of mounting cyberthreats, in ways that traditional connectivity cannot match.

“Quantum communications uses principles of quantum mechanics and advanced mathematics to generate provably secure communications channels, resilient to cyberattack,” explains Dr Joe Spencer, quantum technology specialist with consulting firm Global Quantum Intelligence. The longer-term impact will go beyond security, he argues. “On top of improved resilience, quantum comms opens up new channels for developing a connected world through a quantum internet.” 

As an example of this latter idea in action he cites EuroQCI, a prototype infrastructure initiative backed by the European Commission in collaboration with the European Space Agency. When complete it will integrate quantum-based systems with existing fibre networks and span the whole of the EU.

But it is the battleground of safeguarding sensitive and valuable data where most of quantum’s early use cases are likely to be found. Secure wide area communications have traditionally relied on public key infrastructure (PKI), whereby data is encrypted and despatched over fibre, accompanied by the digital keys needed to unlock it at the other end. But basic binary encryption of this sort leaves data vulnerable to well organised bad actors, able to intercept and copy information in transit without leaving any evidence of their activity. Quantum secure communications uses photons of light to transmit data in the form of quantum bits, or qubits. Any attempt to access these qubits in transit will degrade them and leave signs of interference.

“Quantum communications uses principles of quantum mechanics and advanced mathematics to generate provably secure communications channels, resilient to cyberattack”

Dr Joe Spencer, Global Quantum Intelligence

An important emerging quantum technology model is quantum key distribution (QKD), whereby data is locked and unlocked using robust cryptographic keys. QKD is already applicable today in point-to-point metro-level connectivity, but its big limitation is that it relies on “trusted” nodes which at present can be spaced up to 100km apart. Data must be decrypted and re-encrypted at each of these nodes, but can’t pass through the kind of amplifiers used by intercontinental fibre networks. The next frontier, while a new generation of quantum-compatible repeaters and amplifiers is being developed, lies logically with satellite communications and its potential to allow qubits to be sent securely all over the world via space.

China is setting the pace with satellite-driven QKD, having established a proof of concept back in 2016. It is currently working to refine secure links between LEO (low Earth orbit) satellites and optical ground terminals, with its Micius satellite having already proven the feasibility of quantum cryptography by carrying traffic to remote corners of China. Catch-up projects are ongoing across Europe and North America, supported by a mix of public and private sector interests from governments and universities to technology vendors and start-ups.

The quantum race to deep space

In October 2023, space agency NASA launched the Psyche mission, bringing to life its pioneering Deep Space Optical Communications (DSOC) experiment. DSOC is all about proving that it is possible to transmit data at high rates from deep space using single-photon quantum optical communication rather than the decades-old radio wave communications used for space connectivity. When Psyche reaches Mars it will be the first step in a long-term plan to stream video from deep space. Higher data rates could allow future deep space missions to carry more sophisticated scientific instruments and return more data than is currently possible.

Optical communication can already offer much higher data rates for telecommunications satellites in low-Earth orbits. But to use it at deep space distances will necessitate high-power, high-accuracy lasers and super-sensitive single-photon detectors that do not yet exist with the required performance.

QKD in the UK

The UK is a centre for pioneering QKD research. The Yorkshire-based Quantum Communications Hub is one of the main players in a consortium that is bidding to turn quantum science into mainstream technological applications for economic benefit. It has collaborated with BT and Toshiba on commercial quantum communications trials on behalf of EY and HSBC. 

Professor Gerald Buller of Heriot-Watt’s Institute of Photonics and Quantum Sciences is the Hub’s principal investigator-designate. “It will be interesting to see where the UK goes in terms of infrastructure,” he says. “The Chinese are obviously well ahead of us with three large satellites in play. We need to be in the game, and require a satellite program to support that. Really the only way to do that is to link with other countries, perhaps with the US or the EU.”

He describes the work of BT and Toshiba as “brilliant, but local”. “And we’re talking low data rates,” he cautions. “The real challenge is to do this at much higher rates.”

Given its current state of evolution, Buller doesn’t see quantum communications overtaking and replacing traditional optical networking any time soon, probably remaining complementary for a number of years yet. “PKI’s problem is that quantum computing will before much longer render much of it insecure,” he says. “People talk of a ‘Q-Day’ when PKI becomes effectively obsolete, but I think the future is a bit more nuanced than that. Quantum is certainly part of the solution, and the future might be one of hybrid classical and quantum systems.” 

Looking to the longer term, Buller believes the direction of travel will take us beyond today’s trusted node QKD and towards the galaxy of possibilities offered by quantum entanglement: “Entanglement will give us huge advantages on the security side,” he says. “It will be usable in quantum repeaters, so can support communications over very long distances.”

“Entanglement will give us huge advantages on the security side”

Professor Gerald Buller, Institute of Photonics and Quantum Sciences

But what is quantum entanglement? Defining it is where the science can get confusing for the physicist and non-physicist alike. Famously described by Albert Einstein as “spooky action at a distance”, quantum entanglement is a counterintuitive concept with important implications for a new generation of communications. It is based around the phenomenon whereby two subatomic particles, photons or electrons, can have an intimate linkage with each other, even if separated by a considerable distance, perhaps even by billions of light years. Despite geographic separation, a change induced in one will affect the other.

Jasper Krauser, quantum technology central coordinator with Airbus, an infrastructure provider in the aerospace sector, offers to decode its significance. “If you want to really exploit quantum technologies and what they can do in terms of computing and sensing, you need to be able to connect different quantum devices,” he explains. “This won’t be like the internet as we know it today with bits of information flying around. Instead you will need quantum entanglement to be able to share information between these different devices.”

Entanglement, he says, will allow quantum information to be sent from one quantum computer to another such that distance is irrelevant: “There are operational challenges to overcome first,” warns Krauser. “We will need, for example, quantum repeaters that we don’t have today. The best we have at present is just a precursor to a full quantum information network.”

Along with the lead being taken by private sector interests like Airbus, much of the thought leadership on quantum entanglement, and related quantum disciplines, is happening in academia. The University of Bristol’s Quantum Engineering Technology Labs (QET Labs), for example, has already experimentally demonstrated entanglement-based quantum key distribution over a range of 144km. It is also a pioneer in the field of “quantum advantage”, working with researchers at Imperial College London and Hewlett Packard Enterprise to demonstrate how a quantum computer can perform a task much faster than the world’s most powerful supercomputers. The University of Bristol has also worked with the University of Waterloo in Canada and the University of Strathclyde in Glasgow to test new ways of distributing quantum encryption keys from space.

A lot is at stake with the next stages of the evolution of quantum communications. Step one is to get the technology refined and deployed at scale ahead of the cybercriminal fraternity. The next step will be to develop and popularise chargeable services that work reliably. Then we can start to imagine a world where quantum devices communicate securely and with no distance limitations, offering a likely basis for how the digital economy of the future will function.

Banks, energy, healthcare, and pharma

As a market for quantum communications products and services opens up, what are the early opportunities for start-ups and investors likely to look like?

“Depending on the solution implemented, whether that is a software-based algorithm or a hardware-based photonic system, there are numerous opportunities,” believes Dr Joe Spencer of consulting firm Global Quantum Intelligence. “In the QKD sector, hardware is necessary such as photon sources and detectors, as well as quantum repeaters and integrated systems. Early opportunities of a services nature might be in the area of providing test-beds and analysis to assess products and software libraries against emerging standards.”

Which industry sectors are likely to be the early adopters? Here’s a few likely ones:

  • Banks are already safeguarding sensitive customer information with quantum technology. Some, for example, are using quantum random number generators (QRNG) to produce keys that are the basis of cryptologic operations such as authentication, digital signatures and secure access control. It is vital that banks are able to protect valuable data while ensuring that it is available for transactions on a real-time basis.
  • With credit card fraud costing about $14 billion a year globally, quantum communications technology is already showing potential for encrypting credit cards and protecting them from criminal organisations. Unhackable credit cards that use quantum cryptography are in the pipeline. Such a card would contain a strip of nanoparticles instead of a magnetic stripe or embedded computer chip. A laser directed against the nanoparticles would create a unique pattern.
  • Quantum communications is expected to allow governments and defence departments to protect large amounts of classified data, both within borders and on a global scale. The most dependable way to avoid state-sponsored espionage will be through unbreakable quantum key exchange.
  • Much confidential healthcare information currently resides in data centres, sometimes on public cloud platforms. Quantum key distribution is already being trialled to provide long-term security for such data.
  • On the agenda of every energy producer is finding better ways to transmit power efficiently and sustainably over a stable grid. The networking of quantum sensors over a wide area could be used for measuring magnetic fields, temperatures and other parameters with precision, enabling better grid monitoring.
  • Pharmaceutical and biomedical companies need to protect sensitive patent information resulting from a development cycle that might be up to 10 years long. Like banks, they have the resources to invest in cutting-edge security solutions to offset the risk of hackers.
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Guy Matthews
Guy Matthews / Writer

Guy has been a technology journalist for over 35 years during which time he has edited and written for numerous newspapers and magazines. A particular specialism for the past 20 years has been the market for wholesale telecoms services. As one of the main freelance writers for Capacity magazine, Guy has written in depth on topics ranging from developments in subsea cabling and the evolution of the Internet of Things to Carrier Ethernet standards and the challenges of network security. He has also contributed to European Communications, Mobile Europe, Vanilla Plus, IoT Now and The Register.