Communication security is a basic requirement for national information security and human economic and social life. For thousands of years, people’s pursuit of communication security has never stopped. However, traditional encryption techniques based on computational complexity have the potential to be deciphered in principle. As math and computing power continue to increase, the possibility of classic passwords being deciphered is increasing.
Quantum Secure Communication is the only known secure communication method that cannot be eavesdropped and undecipherable. On August 16, 2016, China successfully launched the first quantum science experimental satellite "Mozi".
Recently, the Chinese Academy of Sciences held a press conference in Beijing to announce that the "Mozi" quantum science experimental satellite has successfully and fully realized all three established scientific goals, and continues to lead the world in quantum technology development and spatial scale quantum physics in the future. The frontier research of problem testing has laid a solid foundation for science and technology.
Professor Pan Jianwei from the University of Science and Technology of China and his colleague Peng Chengzhi and other research teams, combined with the Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Wang Jianyu Research Group, Microsatellite Innovation Institute, Photoelectric Technology Research Institute, National Astronomical Observatory, etc., Space Science Strategy in Chinese Academy of Sciences With the support of the Sex Science and Technology Special Project, using the "Mozi" quantum science experimental satellite, the quantum key distribution from satellite to the ground and the quantum teleportation from the ground to the satellite have been successfully realized for the first time in the world.
The two results were published online on August 10 in the internationally authoritative academic journal Nature. This is the space that the Chinese scientists took the lead in realizing the two-dimensional quantum entanglement distribution of the kilometer-level star field and the non-locality test of quantum mechanics. The space realized by Chinese scientists using the "Mozi" quantum satellite was published. Two other major breakthroughs in quantum physics research.
Bai Chunli, dean of the Chinese Academy of Sciences and secretary of the party group, said that the "Mozi No." opened the door to global quantum communication, space quantum physics and quantum gravity experimental testing, and for China to seize the commanding heights of quantum technology innovation in the international arena and become an international peer. The benchmark has achieved the transformation of the "leaders".
It is generally believed that the main research contents of quantum communication include quantum key distribution (quantum secret communication) and quantum teleportation.
Through the transmission of quantum states, quantum key distribution shares unconditionally secure keys in users in remote places, and uses this key to encrypt information once and for all. This is the only known non-stealing and undecipherable human being. Unconditional and secure communication.
“In general terms, quantum key distribution is like a person who wants to pass a secret to another person. It needs to pass the secret box and a key to the recipient. The receiver can only use the key to open the box. To the secret. Without this key, others can't open the box, and once the key is touched by others, the transmitter will immediately find out that the original key is invalid and give a new key until the recipient gets it. "Pan Jianwei said.
Outer space optical signal loss is small, satellite assistance can greatly expand quantum communication distance
Quantum communication usually uses single photons as physical carriers. The most direct way is to transmit through optical fiber or near-surface free space channels. How to realize safe, long-distance, practical quantum communication is the biggest challenge in this field and the common goal of the international academic community for decades.
Wang Jianyu, a researcher at the Shanghai Institute of Technical Physics of the Chinese Academy of Sciences and executive deputy chief of the Quantum Science Experimental Satellite Engineering, said: "Using the almost vacuum in outer space and thus the loss of optical signals is very small, satellite communication can greatly expand quantum communication. At the same time, because satellites have the unique advantage of easily covering the entire earth, it is the most promising way to achieve ultra-long-distance practical quantum cryptography and quantum teleportation on a global scale."
Since the beginning of this century, this direction has become the focus of intense competition in the international academic community. The Pan Jianwei team carried out a series of pioneering experimental studies to realize the quantum communication of Xingdi.
Lay a solid technical foundation for building a globally secure quantum secure communication network
The completion of the Xingdi high-speed quantum key distribution experiment is one of the scientific goals of the "Mozi" quantum satellite.
Pan Jianwei said that this important achievement has laid a solid technical foundation for building a quantum secure communication network covering the whole world. Based on the distribution of the quantum key of the satellite, using the satellite as a trusted relay, key sharing can be realized at any two points on the earth, and the quantum key distribution range can be extended to cover the whole world. In addition, the quantum communication ground station and the inter-city optical quantum security communication network (such as Hefei Quantum Communication Network, Jinan Quantum Communication Network, Beijing-Shanghai trunk line) can be interconnected to build a world-wide integrated secret communication network.
The quantum teleportation experiment of the Earth Star is one of the other scientific goals of the "Mozi" quantum satellite. Peng Chengzhi said that this important achievement has laid a solid technical foundation for future research on space-scale quantum communication networks and space quantum physics and quantum gravity experimental tests.
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