Breakthrough allows for secure data transfer between cities

Breakthrough allows for secure data transfer between cities [Image: NicoElNino via iStock]

The Cambridge Research Laboratory of Toshiba Research Europe has devised a new way of transferring data securely between cities.

According to the researchers, the range of transfer will extend to over 500 km of standard telecom fibre.

This advance, called Twin-Field QKD (quantum key distribution), enables the protection of sensitive data transmitted in optical networks between cities. It would allow a secure link between cities like London, Paris, Brussels, Amsterdam or Dublin.

QKD’s security relies on encoding each bit of the key upon a single photon (particle of light) transmitted, for example through an ordinary optical fibre. The researchers explained that any attempt to read the photons alters their encoding, which allows the secrecy of each key to be tested and guaranteed.

They added that unlike existing security solutions, quantum cryptography is secure from all future advances in mathematics and computing, even from a quantum computer. They therefore expect it to be an essential tool for protecting communication infrastructure from cyber attacks in the future and giving businesses the advantage when it comes to protecting operation-critical information.

Dr Andrew Shields, assistant managing director at the Cambridge Research Laboratory, said: “Twin-Field QKD would enable a bank in London to connect to a data centre in Leeds via a link that can guarantee the secure transmission of customer data.

“At present, the bank would have to place trust in intermediate nodes at secure, guarded locations between London and Leeds. Our breakthrough means that businesses can create a QKD network that connects their sites across the country for the first time.”

Until now, the typical range of QKD has been limited to a few hundred kilometres of optical fibre because the photons carrying the information can be scattered, and thereby lost from the fibre. This then reduces the rate at which secret keys can be formed.