The serious and ever-evolving threat posed by cybercriminals is forcing governments, businesses and communications providers to explore more secure methods of transmitting critical information.
The traditional way is encrypting data and sending it over fibre, along with the digital keys needed to decrypt it. But wrapping data and keys in binary forms leaves them vulnerable to increasingly well-organised and well-funded bad actors with the means to intercept and copy information in transit, usually without leaving any evidence.
An emerging alternative is quantum secure communications. This leverages the laws of quantum physics to turn digital ones and zeros into something far less crackable. It uses light, in the form of photons, to transmit data as quantum bits (qubits). Qubits degrade if they are tampered with while in motion, which becomes a tell-tale sign of interference.
A version of this technology – quantum key distribution (QKD) – is a practical reality in point-to-point metro-level connectivity, with data locked and unlocked using robust cryptographic keys based on light’s quantum properties. But there are limitations it.
“This kind of communication is reliant on ‘trusted’ nodes, around 100km apart and connected with fibre,” explains Tim Spiller, hub director of the UK-based Quantum Communications Hub. “Information needs to be decrypted and re-encrypted at each of these physical nodes. In a small country like the UK, you might only need a few of them and fan out from there. BT and Toshiba have done a commercial trial in London with EY as a customer.”
But QKD’s 100km limit means it is of no use for intercontinental communications, not least because quantum secured communications cannot pass through amplifiers used by undersea fibre. The solution to photons degenerating over longer distances appears to lie with satellite communications, which could allow quantum secured information to be sent across the world.
At present, this is a concept rather than a commercial reality, as a there are a number of practical hurdles to overcome before billable services can be offered. But efforts to resolve them are underway. Since a China-led initiative established a proof of concept, work has being continuing on refining secure links between low Earth orbit (LEO) satellites and optical ground terminals. In 2016, China’s Micius satellite demonstrated the feasibility of satellite-based quantum cryptography, combining it with a fibre-based QKD backbone to carry traffic securely to remote areas of China. Several projects across Europe and north America, backed by consortiums of public and private sector interests, including governments, academia, technology vendors and players from the satellite comms sector, are currently underway.
“If you have one station on the ground and a single satellite in space, then they can only communicate once a day, so you need to build up a network of ground stations,” explained Dr Ross Donaldson, research fellow at Heriot-Watt University. The University is collaborating with the Quantum Communications Hub to establish optical ground stations to receive quantum encrypted signals at Errol Airfield, near Perth in Scotland. “The ground station is therefore the most important aspect of making quantum communications over satellite cost effective. That’s my area – making the ground station side more practical, higher in performance and cheaper.”
With much work to be done both on the ground and in space, what future use cases look like is a matter of conjecture. Donaldson predicts that the military and financial industry will find applications for it.
“The technology could be used for sharing encryption and digital signatures between ships and aircraft,” he speculates. “The finance sector would be a market too, where you want to make sure large sums of money are secure when transferring them.”
However, he is certain that quantum communication will feature in the next generations of mobile communication technology.
“Optical communications will be a big driver for 6G, and beyond that for 7G, and we can be sure quantum will play a part here,” he says. “People need to be thinking already about how they will integrate quantum and satellite into that.”
Spiller agrees that in order to seize the opportunities quantum encryption provides early, service providers should focus on where high-value information needs to be protected. “It will be applicable where substantial company information is being transferred,” he says. “Banks and governments engaging with each other – not so much consumers. At least, not to begin with.”
Rik Turner is a senior principal analyst with Omdia’s IT security and technology team. He has been watching emerging quantum communications trends with interest.
“I expect uses cases to include very sensitive patent information,” he says. “Think of pharmaceutical and biomedical research. Companies here have money to spend on this sort of solution and valuable information to protect. If you’ve spent 10 years developing a cure for something and someone hacks it, you’re going to be a bit upset.”
The satellite sector is also keeping tabs on developments in quantum security, with future opportunities in mind. Salim Yaghmour, director of space communications innovation at Intelsat, sees a long-term future for quantum security in a range of fixed and mobile broadband applications.
“Internet infrastructure itself can be made as secure as possible,” he says. “Moving from 5G to 6G, it will be critical to secure infrastructure with highly encrypted techniques. This applies to anything transactional where information needs to be stored and secured for a long time. There will be certain [internet of things] use cases as well. In fact, anything where security is vital.”
Along with improved security through quantum key distribution, quantum communications and satellite will have other applications, according to Cyrille Laborde, leader for quantum and optical communications with Thales Alenia Space, which is collaborating with the European Space Agency on a project aimed at developing quantum space-to-Earth communications technologies.
“The first applications of this technology will be around security,” Laborde says. “But there’s also what we call quantum information networking, to improve both the links between quantum computers and sensors and the capacity between various ground systems. When you connect one quantum computer with another, you multiply their capacity. Satellite is necessary for this task because of the distance between them.”
These predictions lead to questions about what technical sticking points is preventing turning research and development investment and proofs of concept into commercial products.
Spiller believes the main task is improving data rates. “The Chinese demonstration showed you can send quantum signals from space and catch them on Earth,” he says. “The next stage is to establish a secure encryption key and use that between ground base stations. But at the moment, key technology is not allowing for a high data rate. Faster light sources from space and better detection on Earth will push the key distribution rate up and let you provide a more competitive offering.”
Satellites need to get bigger and better too, he adds. “At the moment we have some very small satellites up there proving the concept, the size of a shoebox. Bigger and more robust satellites will support multiple tasks. The satellite technology is already there. It’s the appropriate quantum technology to put on them that needs to be developed. Plus, there’s scope for improvement in the efficiency of detection equipment on the ground.”
Turner believes that much of the next wave of development will happen in academia, with the support of private investment. “Satellite companies will be keeping an eye on this, perhaps employing some research people to look at it,” he says. “Vendors with technology in the optical sector will be doing plenty of work, and governments are interested, hyperaware that China is ahead here, or certainly were a few years ago.”
There are other important constraints, according to Yaghmour, including practical and conceptual issues that must be considered.
“The other constraint is around distance,” he says. “When you transfer a photon over more than metro distance, performance is not good. Implementation costs are another important factor if you want to transfer this to large commercial operations. Thinking is needed on commercialisation. Interoperability is an issue too, with a need for a standard algorithm to connect source with destination over the solutions of multiple vendors. It’s not in place and could take some time.”
Yaghmour notes that Intelsat is still in the early stages of evaluating QKD, but a lot of engineering work has already been done to assess its possibilities. Meanwhile, the satellite company is a member of several working groups that are helping to develop a roadmap for the technology, and solutions for different use cases.
“Perhaps the biggest barrier is around cost of devices,” Yaghmour concludes. “When that is solved, I see commercialisation within five years or so. Perhaps not on a large scale, but something that can be hosted on a satellite. Eventually space with be just another network node, with more and more space connectivity deployed to support different applications.”
Laborde believes security-driven applications will come online in three to four years.
“I expect vendors like Cisco and Toshiba coming up with solutions here,” he says. “In the same timeframe, we’ll see some new satellite capacity for [QKD], making new service possible. Then it could be another three years before these services are fully operational, by 2030 ideally. A number of technical developments need to happen first, mostly around taking technology in the ground and getting it into space.”
The ultimate goal is what technologists are dubbing the “quantum internet of things” – the ability to connect quantum computers in any part of the globe and deploying sensors in every kind of remote location. But the answer to whether quantum communication will replace today’s internet or become a niche channel, only carrying the most valuable data remains in the stars.
