Researchers break the world record for quantum-encrypted communications

According to The Eurasian Times, researchers in Beijing have set a new world record for quantum-encrypted communications also called as quantum secure direct communication (QSDC) of 102.2 km (64 miles), breaking the previous record of 18 km (11 miles).

Quantum-Encrypted Communications – Securing Networks

Transmission speeds were extremely slow at 0.54 bits per second, but adequate for text message and phone call encryption over a distance of 30 km (19 miles), according to Long Guile, the study’s lead author, in Nature. Because any eavesdropping attempt on a quantum line can be detected instantly, the work could eventually lead to hack-proof communication.

To secure networks, QSDC employs the entanglement principle. According to quantum physics, entangled particles are linked in such a way that if you change the property of one by measuring it, the other will instantly change, effectively making hacking impossible. In theory, even if the particles are light-years apart, they remain linked, so such systems should work over long distances.

‘Novel design of physical system with new protocol’

The same research team set the previous fiber record, and devised a “novel design of physical system with a new protocol” to achieve the longer distance. They simplified it by eliminating the “complicated active compensation subsystem” used in the previous model. “This enables an ultra-low quantum bit error rate (QBER) and the long-term stability against environmental noises.”

As a result, the quantum-encrypted communications system can withstand much more so-called channel loss, which makes decoding encrypted messages impossible. As a result, they were able to extend the fibre from 28.3 km to the record-breaking 102.2 km. “The experiment demonstrates that intercity quantum secure direct communication via fiber is feasible with current technology,” the researchers wrote in Nature.

Researchers in China previously made a secure quantum-enabled video call by satellite, but fiber poses a different set of challenges. “If we replace parts of the internet today, where more eavesdropping attacks happen, with quantum channels, those parts will have the added ability to sense and prevent eavesdropping, making communication even safer,” said Long.