More than 700 optical fibers with two earth-satellite links to distribute quantum keys over 4,600 kilometers constitute what is the world’s first quantum communication network .
Behind the project, as published in a study in Nature, is a team of Chinese scientists led by Jianwei Pan, Yuao Chen, Chengzhi Peng from the University of Science and Technology of China in Hefei (USTC).
Impossible to hack
Quantum communication is based on the exchange of quantum keys (QKD), which uses the quantum states of the particles to form a chain of zeros and ones, while any interference between the sender and receiver will change this string or key and it will be noticed immediately: therefore, unlike conventional encryption, quantum communication is considered impossible to hack .
Specifically, the foundation of this technology lies in the fact that each pair of entangled photons encodes one bit of key information. Its entanglement guarantees that if one of the photons is altered, for example, because someone has managed to observe it, its physical properties change instantly and the entanglement is broken, so the encrypted message cannot be compromised.
Until now, the most common QKD technology uses fiber optics for transmissions of several hundred kilometers, with high stability but considerable channel loss, but researchers have gone further using a new technology called double-field QKD (TF-QKD).
They also aim to develop cost-effective small-scale QKD satellites and terrestrial receivers, as well as medium and high earth orbit satellites to achieve ten thousand kilometer level QKD all the time. For its part, the European Union has also been launched with an initiative called the European Union Quantum Communication Initiative