BT is preparing to build the UK's first "data centre to data centre" quantum-secure connection to test tech that will secure the nation against emerging threats, including "store today, decrypt later" attacks.
The great fear of today is that bad actors are busily amassing huge stockpiles of encrypted material and waiting for the day when quantum computers make it easy to crack them open, potentially revealing everything from trade secrets to hugely sensitive classified nation-state documents.
Quantum key distribution (QKD) is one solution, offering encryption that cannot be broken (for now) and will, therefore, keep data secure as we move into a new era of computing.
The network will stretch between one data centre in Slough, an unglamorous satellite town near London, and the new-build financial district of Canary Wharf.
All data transmitted between the data centres will be protected by Quantum Key Distribution (QKD), which BT described as "unique because the key exchange is secure against any computational or mathematical advance."
The connection uses pre-existing fibre and sends the actual data as usual, with keys exchanged by transmitting the smallest possible units of light, one at a time.
“The data between the data centres is carried as before - it’s just that we’re encrypting it with quantum encryption," Andrew Lord, BT Senior Manager of Optical Research, told The Stack. "So we also need to carry that quantum encryption on that fibre by sending single photons of light.
“What we’re doing is taking a laser and turning it right down so there’s literally just one photon at a time coming out of it. It’s an incredibly dim light source transmitted using fibre infrastructure."
Sending the single packet of light makes the transmission more secure for a number of simple and complex reasons, Lord explained.
“If I was sending a secret key using big chunks of light - each pulse would be carrying billions and billions of photons," he added. "If someone were to come along and steal a few, we wouldn’t notice. Even if you sent a secret key through billions of photons, the reciever wouldn’t notice if 5% was stolen.
“If a single photo is stolen - it’s gone. You can’t steal half a photon. When it's stolen, the key is gone and cannot be used. It’s intrinsically secure.”
Quantum computers and the double-slit experiment
The next step up into the quantum realm of complexity shows us that when a photon of light is speeding through a fibre optic cable, it also cannot be interfered with or even observed without the sender or recipient knowing.
Understanding why involves a quick trip into the sometimes bewildering laws of quantum physics and a flashback to the famous double slit experiment, which shows that particles like photons or electrons exhibit both wave-like and particle-like properties - depending on whether they are being observed.
If the particles are fired through two closely spaced slits and hit a screen, they create an interference fringe pattern characteristic of waves. However, if the particles are observed or measured at the slits, the interference pattern disappears, and they behave like particles.
The mechanics of the quantum realm mean that hackers are not able to access the key being sent (or observe it, in quantum terms) without causing a fundamental change that's easily picked up by defenders.
“Hackers want to go unnoticed," Lord continues. "But that doesn’t work because quantum physics stops you from looking at something without changing it. You cannot observe a photon without somehow getting involved and changing the state of that photon. That principle of quantum physics is relied upon by this encryption technique.”
Building a quantum-safe connection
The Great British quantum data centre connection will be built in collaboration with BT, Toshiba, and Equinix, which operates the facilities.
Howard Watson, Chief Security and Networks Officer at BT Group said the project "marks an important milestone in our journey towards accelerating the commercialisation of quantum-secure connectivity".
"With quantum technologies moving at an incredible speed, we continue to explore and test the practical technologies emerging from this highly innovative field to secure the UK’s digital infrastructure against future quantum threats," he said.
Previously, BT and Toshiba also joined forces to build and trial the "world’s first commercially available quantum-secured metro network."
Announced in 2021, the network connects sites in London’s Docklands, the City and the M4 Corridor, and provides data services secured using QKD and Post-Quantum Cryptography (PQC).
A range of quantum-secured services, including dedicated high bandwidth end-to-end encrypted links are available over the network, which is delivered using Openreach’s Optical Spectrum Access Filter Connect (OSA FC) solution for private fibre networks. QKD links are provided using a network including both core and access components, with Toshiba providing the quantum key distribution hardware and key management software.
HSBC was the first bank to trial the metro network, sending quantum secure test data over fibre-optic cables between its global HQ in Canary Wharf and a data centre in Berkshire, 62km away.
At the time, it described QKD as "an important technology that uses particles of light and the fundamental properties of quantum physics to deliver secret keys between parties", which relied on "keys that can be used to encrypt and decrypt sensitive data and are safe from eavesdroppers or cyber-attacks by quantum computers."
Talking about the latest quantum adventure, Bruce Owen, Managing Director UK at Equinix said: “We understand just how complex today’s digital challenges can be, which is why we are pioneering the democratisation of quantum secure communications, making it accessible as a service to thousands of businesses worldwide. This collaboration with BT Group and Toshiba is a welcome opportunity to enhance our customers’ access to innovation that will build resiliency in the quantum computing era.”
Hiroshi Tsukino, Corporate Officer and Corporate Vice President of Toshiba Corporation, and Vice President of ICT Solutions Division at Toshiba Digital Solutions, said the trio are working to build "ultra-secure networks that will be the bedrock for the future quantum internet".
“Our collaboration with BT Group and Equinix is a critical next step on our shared journey to commercialise QKD services in the UK, bringing quantum-secure communications to more organisations," he said. "We are focused on ensuring all businesses are provided with the opportunity to protect their data from retrospective attacks with a quantum computer."
When will quantum computers be available and break encryption?
The quantum threat is often referred to as "Y2Q", which is a nod to the infamous millennium bug that sparked more than $300 billion of IT panic buying. Unfortunately, Y2Q could end up even more expensive than Y2K.
"We do not have a good estimate on the overall cost of the transition to quantum-safe cryptography, but the size and complexity of Y2Q are significantly larger than Y2K, which makes it necessary to develop solutions over the next couple of decades," the World Economic Forum warned at the end of 2023. "Organisations need to start preparing as soon as possible.
To do this, the World Bank advisers leaders to start by collecting and understanding all information about the cryptography used for various applications within their company, so they can predict post quantum cryptography and hybrid algorithms would affect the performance.
"They should prepare a well-defined roadmap to start the actual migration," it advised. "In this phase, the transition to quantum-safe cryptography should be implemented in all systems across the organization. The upgraded systems should then be tested and validated for their expected security, functionality and performance."
If we gaze even further into the future, there may be a day when even PQC can be cracked.
“There are people out there trying to crack PQC, and we’re seeing publications in learned mathematical journals trying to apply the same techniques that have broken current cryptography with quantum computers to break PQC as well," said BT's quantum researcher Andrew Lord. "They haven’t managed it yet. Maybe they won’t. How long is PQC safe? Probably a very long time. But there’s an underlying doubt.”
It’s difficult to say exactly when quantum computers will arise to grind ye olde encryption into the dust of history. Yet he did set out a rough prediction for the development of this game-changing technology, which contains a strong note of optimism.
“Quantum computers are obviously in their infancy, and to break the codes that we’re talking about would require a device that is extremely powerful," Lord said. "But there are a lot more useful, positive things a quantum computer will be able to do with powers less than it needs to break encryption, such as chemistry or finding new drugs.
"To perform these tasks, quantum computers will not need to be as much of a beast as one capable of breaking codes. So that’s good news because it means that quantum computers will be a force for good before they start doing the bad things.”
How are you preparing for Y2Q? Get in touch with jasper@thestack.technology to let us know.
