Speaking at Mobile World Congress in September, Luke Ibbetson, Vodafone’s Head of R&D said, “Quantum computing is by far the biggest revolution in computing since the 1950s.”
This is no exaggeration. Quantum computers will be able to perform calculations beyond the capabilities of classical computers, including those involved in cracking public-key cryptography algorithms. These encryption techniques are used today to protect much of our valuable data – from WhatsApp messages to bank transfers. What happens when these fortresses fall?
At the forefront of this discussion are telecom providers who are responsible for ensuring network security. But even as the threat of quantum computing evolves from theory to reality, creating a quantum-secure network has proven to be an ongoing challenge. Solutions have always had a significant downside: either a high bill for overhauling an entire network, or trade-offs in distance and performance of existing networks. With new innovations in this field, that will all change.
A growing threat
Quantum computers have been discussed in academic circles since the early 1980s. However, despite ongoing research, they remained a pipe dream until private investment accelerated innovation in recent years. Understandably, the conversation about the threat such computers posed to cybersecurity had always felt somewhat academic.
Thanks to a recent innovation arms race, companies around the world have been competing to harness the computational advantages of quantum, with IBM releasing the first integrated quantum computing system – IBM Quantum System One – in 2019. Shortly thereafter, Google’s 54-qubit Sycamore processor performed a computation in 200 seconds that would have taken the world’s most powerful classical supercomputer 10,000 years.
Not only do quantum computers exist today, but Fujitsu predicts that it will not produce its first commercially available quantum computer until next year.
There is understandably a lot of excitement about the potential benefits of quantum computing, including increasing the accuracy of molecular simulation, faster and cheaper drug development and discovery. However, these advantages are outweighed by the fact that once the technology is available on the commercial market, it is no longer controlled and its power can be used for nefarious means.
In fact, malicious actors have already started harvesting data protected by traditional public-key cryptography in “harvest now, decrypt later” attacks: they already anticipate the commercial availability of quantum computers that will enable them are going to crack them. As we reach the edge of this reality, there is increasing concern from scientists and industry associations about the development of quantum-safe technologies.
Quantum Safe Solutions
In July, the US National Institute of Standards and Technology (NIST) selected four encryption algorithms that it believes will be more resilient to known quantum computing algorithms. The World Economic Forum predicts that 20 billion devices will need to be upgraded or replaced over the next two decades to support new forms of quantum-resistant encryption.
Furthermore, the network itself is a key point to resist the threat by protecting data in transit. A tremendous amount of investment and research has gone into the problem of how to create quantum-safe networks; Quantum Key Distribution (QKD) has proven to be an exciting field here.
QKD technology leverages the laws of quantum physics to ensure that even with powerful new quantum computers, attackers cannot decrypt data in transit, while maintaining security over other high-performance computers.
For telecom providers, QKD technology offers a way to protect customers from current and future cyber security threats. However, integrating QKD into existing networks has traditionally led to complications, including the need to introduce dedicated dark fiber cables alongside the original infrastructure to carry the QKD signal.
Implementing additional dark fibers might be feasible for some sections of the network, but metro and “access tail” environments – which are often built-up locations such as cities – pose a significant challenge: it would be expensive for telecom providers to use dedicated ones Fiber optics to be used within the underground segment of the network. Such obstacles prevent many vendors from making rapid progress with the installation of quantum-proof technologies.
Multiplexing: opportunity and obstacle
Wavelength Division Multiplexing (WDM) is a common technique used in fiber optic networks that places many different optical data wavelength channels on the same fiber, greatly increasing the data carrying capacity of the fiber.
WDM – or simply “multiplexing” – is the simplest solution for integrating QKD into existing telecom carrier fibres, carrying the secret encryption keys on the fibers already carrying traditional telecom data services.
In the past, QKD was typically implemented on dedicated fibers. However, dark fiber can be a scarce and valuable commodity, especially in metro networks. The dedicated fibers previously required for QKD could be used more profitably for customer data or may not be available at all. The ability to combine QKD and data signals on common fibers using WDM is key to the conundrum for telecom operators.
From possible to feasible
New technologies bring hope to the cause as the quantum threat looms ever closer. Toshiba has been pioneering quantum-safe solutions for decades, but we have now discovered a technique that allows multiplexing on the same fiber without sacrificing performance.
Although it is possible to multiplex QKD signals into the C-band (around a wavelength of 1550 nm) traditionally used for data traffic, the best performance is achieved when the quantum channel is placed in the O-band at 1310 nm . This allows a degree of spectral separation between the QKD (at 1310nm) and conventional data signals (around 1550nm) within the optical fiber, allowing more effective filtering of the noise generated by the strong data signals.
While QKD has been available over dedicated fibers for some time, this innovation makes QKD economical for the first time, including for the access tails to the customer. With this system, it is possible to easily implement QKD into an existing network infrastructure without having to introduce new fibers for the quantum signals – radically reducing the quantum security costs of a current infrastructure. Meanwhile, with this brand new multiplexing technique, providers can also maintain existing performance standards.
Two factors have come together to make this a particularly important time for telcos to plan for adapting their infrastructure. Rapid advances in quantum computing mean that the cybersecurity threat has become more real and urgent. Meanwhile, for the first time, new multiplexing technology makes it possible for telcos to integrate QKD without having to choose between a prohibitively expensive overhaul to install dedicated Dark Fires or a performance hit with previous types of multiplexing.
With this exciting new innovation, telecom providers can protect their existing network from the future quantum threat while delivering the transmission distance and speed their customers demand.
About the author
Andrew Shields leads R&D and business development at Toshiba Europe for quantum technologies. According to Google Scholar, he has published over 500 research papers and patents in the field of quantum devices and systems, which have been cited over 23,000 times and have a Hirsch Index of >70. He co-founded ETSI’s Industry Specification Group for QKD and served as chair for several years. He is a member of the management team of the EU OpenQKD project and heads the AQuaSeC consortium developing next-generation quantum communication technology.
Featured image: ©Eduard Muzhevskyi