Anyone for quantum-as-a-service?

Is QkaaS (quantum keys-as-a-service) about to become one of our industry’s next acronyms? BT must hope so. Its ongoing research into quantum-secured networks with Toshiba is getting closer to commercialization with a trial of quantum-secured metro network services in London. BT’s Senior Manager of Optical Research, Andrew Lord discussed what the telco is up to. BT is one of a number of communications service providers (CSPs) worldwide looking to secure its data and those of its customers from hackers who in the future will be able to use quantum computers to unlock encrypted data. The world is still several years from quantum computer-enabled security attacks – BT cites estimates of between 5 to 10 years. Nonetheless, the problem is already pressing because encryption used to secure data today could be cracked in the future when a sufficiently powerful quantum computer is available.

BT and Toshiba have been working together on quantum-based security for several years. They have now announced they will build and trial a

commercially available quantum-secured metro network connecting sites in London’s Docklands, the City and the M4 Corridor,

Much of the BT research team’s recent efforts have focused on ensuring it can transmit data secured using quantum key distribution (QKD) and post-quantum cryptography (PQC) over BT’s standard fiber networks, some of which are decades old. “Rather than doing the basic physics which is largely done, it’s been around…getting it to work on standard BT fiber,” said Lord. “If this needs really special [fiber], that’s not going to be good for us,” he said, explaining that the choice was between “building a dedicated quantum service using dedicated fiber, or enabling quantum and data channels to work on the same fiber. I think customers might…want …the whole thing in one package. And it’s that latter that we’ve been…pushing.” The trial will also evaluate how the technology behaves on a network, rather than between two points.

“What we need to do, and what the industry needs to do, is explore how quantum works within a network scenario, because we don’t just have a collection of points.”

Sending keys through space BT's and Toshiba's trial will initially focus on enterprise customers carrying sensitive data, such as database backups between sites, and will explore potential future services such as encrypted links and “quantum keys-as-a-service”. BT will also be able to use the QKD and PQC technology to secure its own networks. “Any classical security mechanism is at risk,” explained Lord, although some forms of security are easier to break than others, namely public key cryptography. Symmetric cryptography, whereby both parties share a private key, is much more secure, he explained.

“If I can get a key from me to you, securely and privately, we’re good to go,” he added. “But the problem is how do I get that key to you?”

BT is addressing the issue of transmitting secure quantum keys, which are photons, via satellite through an exclusive agreement in the UK with the quantum software company Arqit. Although the satellite system is not in place today, the expectation is it will be within the next couple of years or so. “Arqit is…trying to find a solution for large scale network up symmetric keys, so completely bypassing this problem of public key crypto that computers are going to hack into.” The idea, said Lord is that “you distribute the [quantum] keys through space [and] you have ground stations scattered around the globe and you hand over to your fiber distribution system.” “That gives us a head start in providing…global connectivity for banks [for example] for their virtual private networks.” Going the distance Currently, however, the service is limited to a distance of around 100 kilometers. “You don't want to suffer unnecessary losses or attenuation in the fiber because quantum hates attenuation and you really can't afford to lose too many of these photons,” said Lord. However, the limitations of distance are both surmountable and changing, according to Lord. “If you go 100 kilometers, that’s not the end of it…you pop the quantum bits into protected secure, locked away quantum nodes again. So you can build these quantum-safe, trusted nodes around your network.” Lord also expects further innovation from Toshiba to extend the distances over which BT can offer a service.

“This field hasn’t finished; it’s just reached the point where it can be commercialized,” he said. “We can expect this to go on and on for the next 10 years and really improve.”

At the same time telcos, including BT, are trying to find an answer to the separate problem of how to connect quantum computers over a quantum network. “Everybody [worldwide] is working on this…project to build interconnected quantum computers using quantum communications. That’s a big next step [and] I think we will be taking both of those directions …in parallel.”