According to The Eurasian Times, researchers in Beijing have achieved a new world record for quantum secure direct communication (QSDC) of 102.2 kilometers (64 miles), breaking the previous record of 18 km (11 miles). Transmission speeds were extremely sluggish at 0.54 bits per second, but enough for text message and phone call encryption across a distance of 30 km (19 miles), according to Long Guilu, the study's principal author, in Nature. Because every eavesdropping effort on a quantum connection may be detected quickly, the technique might eventually lead to hack-proof communication.
To protect networks, QSDC employs the entanglement principle. According to quantum physics, entangled particles are connected so that if you change the attribute of one by measuring it, the other will instantaneously change, thereby making hacking impossible. In principle, even if the particles are light-years distant, they remain connected. Therefore such systems should operate over long distances.
The previous fiber record was established by the same research team, who created a "unique design of the physical system with a new protocol" to accomplish the larger distance. They removed the prior model's "complex active compensation component." This permits an ultra-low quantum bit error rate (QBER) and long-term stability in the face of external sounds.
Consequently, the system can survive far greater so-called channel loss, making encrypted decoding information difficult. As a result, they could expand the fiber from 28.3 km to the record-breaking 102.2 km. The experiment demonstrates that intercity quantum secure direct communication through fiber is achievable with current technology, the researchers stated in Nature.
Researchers in China previously used a satellite to make a secure quantum-enabled video conversation, but fiber presents obstacles. Suppose we replace sections of the internet today that are more vulnerable to eavesdropping assaults with quantum channels. In that case, those parts will have the extra capacity to recognize and prevent eavesdropping, making communication even safer, Long explained.