A study led by Quantum Communications Hub researchers has brought the world one step closer to secure conference calls by facilitating quantum-secure communications.
Scientists at Quantum Communications Hub based at Heriot-Watt University have demonstrated a quantum-secure communication taking place between four parties simultaneously. Their research has been published Science Advances.
Since the start of the COVID-19 pandemic, the global dependence on forms of remote collaborative working – such as conference calls – has massively increased. With this, there has been a significant escalation of cyber-attacks on teleconference platforms.
This novel advance in quantum-secure communications could result in conference calls with unhackable security measures reinforced by the principles of quantum physics.
Professor Alessandro Fedrizzi, the senior author, who led the team at Heriot-Watt, commented: “We’ve long known that quantum entanglement, which Albert Einstein called ‘spooky action at a distance’ can be used for distributing secure keys. Our work is the first example where this was achieved via ‘spooky action’ between multiple users at the same time — something that a future quantum internet will be able to exploit.”
Secure communications depend on the sharing of cryptographic keys. The keys used in most systems are quite short and thus can be corrupted by hackers, and the key distribution procedure is at a growing risk from rapidly advancing quantum computers. These increasing threats to data security necessitate new, secure methods of key distribution.
A mature quantum technology known as Quantum Key Distribution (QKD), implemented in this experiment in a network scenario for the first time, utilises the properties of quantum physics to enable the guaranteed secure distribution of cryptographic keys.
QKD has been employed to secure communications for over 30 years, allowing communications of over 400km over terrestrial optical fibre and, more recently, even through space. However, currently, these communications have solely taken place between two parties, restricting the practicality of the technology used to facilitate secure conversations between multiple users.
The system established by the researchers applies a key property of quantum physics – entanglement – which is the property of quantum physics that gives correlations between two or more quantum systems, even when they are separated by large distances.
By utilising multi-party entanglement, the group were able to share keys concurrently between the four parties through a process known as ‘Quantum Conference Key Agreement’, surmounting the confines of conventional QKD systems to share keys between just two users, and facilitating the first quantum conference call to take place with a picture of a Cheshire cat being shared between the four parties, separated by up to 50 km of optical fibre.
The quantum technology exhibited holds the possibility of significantly lessen the resource costs for conference calls in quantum networks in comparison to standard two-party QKD methods. It is one of the first models of the expected advantages of a future quantum internet, which is projected to supply entanglement to a system of globally distributed nodes.
