The world is one step closer to secure conference calling, thanks to collaboration between the Quantum Communications Hub researchers and their German colleagues, allowing a secure quantum conversation to take place between four parties simultaneously.
The demonstration, led by Hub researchers based at Heriot-Watt University, is a timely advance given the global reliance on remote collaborative work, including conference calls, since the beginning of COVID-19 pandemic.
There have been reports of a significant increase in cyber attacks against teleconferencing platforms last year. This advance in secure quantum communications can lead to conference calls with insurmountable security measures, supported by the principles of quantum physics.
senior author, teacher Alessandro Fedrizzi, who led the team in Heriot-Watt, said: “We have long known that quantum entanglement, which Albert Einstein called ‘ghostly action at a distance,’ can be used to distribute secure keys. Our work is the first instance where this has been achieved through “ghostly action” between multiple users at the same time – something that a future quantum internet will be able to exploit. ”
Quantum Security Conference Calls That Rely on Encryption Keys
Secure communications depend on sharing cryptographic keys. The keys used on most systems are relatively short and therefore can be compromised by hackers, and the key distribution procedure is under increasing threat from rapidly advancing quantum computers. These growing threats to data security require new and secure methods of key distribution.
A mature quantum technology called Quantum Key Distribution (QKD), deployed in this demonstration in a network setting for the first time, leverages the properties of quantum physics to facilitate assured secure distribution of cryptographic keys.
The QKD has been used to secure communications for over three decades, facilitating communications over 400km over terrestrial fiber optics and recently even across space, however, crucially, these communications have only taken place between two parties, limiting the practicality of the technology used to facilitate secure conversations between multiple users.
Taking advantage of the entanglement of multiple parts
The system demonstrated by the team here utilizes a key quantum physics property, entanglement, which is the quantum physics property that provides correlations – stronger than any we are familiar with in everyday life – between two or more quantum systems, even when these are separated by great distances.
By taking advantage of the multi-part entanglement, the team was able to share keys simultaneously between the four parties through a process known as the ‘Quantum Conference Key Agreement’, overcoming the limitations of traditional QKD systems to share keys between just two users and enabling the first quantum teleconference to occur with the image of a Cheshire cat shared between the four parties, separated by up to 50 km of optical fiber.
Entanglement-based quantum networks are just one part of a larger program of work that the Quantum Communications Hub is committing to deliver future networks with quantum security.
The technology demonstrated here has the potential to dramatically reduce resource costs for conference calling over quantum networks when compared to standard bidirectional QKD methods. It is one of the first examples of the expected benefits of a future quantum internet, which should provide entanglement to a system of globally distributed nodes.