BT’s first quantum key distribution network

The trial of a commercial quantum-secured metro network has started in London.

Professor Andrew Lord

The BT network enables customers to send data securely between sites by first sending encryption keys over optical fibre using a technique known as quantum key distribution (QKD).

The attraction of QKD is that any attempt to eavesdrop and intercept the keys being sent is discernable at the receiver.

The network uses QKD equipment and key management software from Toshiba while the trial also involves EY, the professional services company.

EY is using BT’s network to connect two of its London sites and will showcase the merits of QKD to its customers.

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ADVA adds quantum-resistant security to its optical systems

ADVA has demonstrated two encryption techniques for optical data transmission to counter the threat posed by quantum computing.  

“Quantum computers are very powerful tools to solve specific classes of mathematical problems,” says Jörg-Peter Elbers, senior vice president, advanced technology at ADVA. “One of these classes of problems is solving equations behind certain cryptographic schemes.”  

The use of three key exchange schemes over one infrastructure: classical public-key encryption using the Diffie-Hellman scheme, the quantum-resistant Neiderreiter algorithm, and a quantum-key distribution (QKD) scheme. Source: ADVA

Public-key encryption makes use of discrete logarithms, an example of a one-way function. Such functions use mathematical operations that for a conventional computer are easy to calculate in one direction but are too challenging to invert. Solving such complex mathematical problems, however, is exactly what quantum computers excel at. 

A fully-fledged quantum computer does not yet exist but the rapid progress being made in the basic technologies suggests it is only a matter of time. Once such computers exist, public key based security will be undermined. 

The looming advent of quantum computers already threatens data that must remain secure for years to come. There are agencies that specialise in tapping fibre, says Elbers, while the cost of storage is such that storing huge amounts of data traffic in a data centre is affordable. “The threat scenario is certainly a real one,” says Elbers. 

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