A 75-mile, quantum-secured, high-speed fiber link has been built in the United Kingdom, the largest internet supplier there has said.
Particles of light, known as photons, carry encryption keys over the same connection as data. Hijacking those photons within the link immediately notifies the system that the keys have become bad — the thief interfering with those keys alters them and then they can’t be used by the interceptor — and the traffic becomes garbled instantly.
It’s “virtually un-hackable,” said Gavin Patterson, outgoing BT chief executive, announcing the link at Internet of Things World Europe that I attended in London last month.
BT and its partners’ pipe is the first real-world, quantum-secured, high-speed network in the U.K, BT claimed in a news release. The fiber runs between Cambridge University’s Engineering Department and BT’s lab in Suffolk. The equipment comes from ID Quantique and ADVA optical networks.
Entwined cryptographic keys, such as is used in quantum-key distribution (QKD) are un-breachable, experts say. That’s because the pieces of subatomic particles used in the key are so intertwined that they impact each other wherever they are physically in the link. It means that a network manager can see at any time if data is getting messed with or erased — the cryptographic key changes. Any interruption becomes thus highly visible very quickly and is consequently tagged. The added benefit is that the changed key can no longer be used.
BT said it has set the link up to demonstrate the security to end users.
BT’s isn’t the first QKD link. The city of Jinan, Shandong Province in China started working with one in May 2017, and Spain has one.
Cambridge, U.K., the site of BT’s quantum network termination, is also where the Quantum Communications Hub (a consortium of eight U.K. universities and private sector enterprises and the group working with BT) has set up a QKD-connected hub of three sites around the city, the consortium said in June. Quantum Communications claims to be able to send ultra-secure data in multiple 100 gigabit channels and to generate photon keys at speeds of two to three megabits per second. Whereas BT said its link sends data at 500 gigabits per second.
Using photons to secure networks
Photons, as used in the quantum-key distribution work, will likely end up securing future networks and could turn out to be a crucial element to upcoming quantum computing overall.
The particles of light are good for moving qubits (quantum information carriers) because they can travel distances and work with fabricated chips, explained the University of Maryland in a news article announcing what it said is a breakthrough in photon-carried quantum computing.
The school said it has invented the first single-photon transistor from a semiconductor chip — a photon transistor, in other words. Traditional transistors are the miniscule routing switches used in every form of computing. Producing a photon-based one, where the switches interact with each other, could “attain exponential speedup for certain computational problems.” Photons don’t natively interact — a prior downside.
“Roughly 1 million of these new transistors could fit inside a single grain of salt. It is also fast and able to process 10 billion photonic qubits every second,” the school said.
“Quantum communications technologies are starting to play a significant role in securing our data and communications,” said Dr. Grégoire Ribordy, head of IDQ on a webpage related to the BT project. It’s coming “in an era where the quantum computer will render vulnerable much of today’s [existing] cryptography.”