Researchers from Beijing have set a new world record for quantum secure direct communication (QSDC), which is now 102.2 km, beating the previous mark of 18 km. This was reported by The Eurasian Times. The data transfer rate was extremely low – 0.54 bits per second, but still enough to encrypt text messages and phone calls at a distance of 30 km, says the head of the study Long Guilu. The work can lead to the creation of a secure connection, as any attempt to eavesdrop on the quantum line can be detected instantly.
QSDC uses the entanglement principle to ensure network security. According to quantum physics, entangled particles are interconnected, so if you change the property of one of them by measuring it, the other will also change instantly, thus making hacking impossible. Theoretically, particles remain connected, even if they are at a distance of light years from each other, so such systems must operate at great distances.
The same research team set a previous record for fiber data transmission and developed a new physical system design with a new protocol to achieve greater distance. They simplified it by abandoning “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 system can withstand much more channel losses, which make it impossible to decrypt encrypted messages. This, in turn, allowed them to extend the fiber from 28.3 km to a record distance of 102.2 km. “The experiment shows that intercity quantum secure direct communication through the fiber is feasible with present-day technology.”
Researchers from China have previously made a secure quantum video call via satellite, but fiber is creating a different set of problems. “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.
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