China has put into operation the world's longest line of secure quantum communication length of 712 km. On her pad took three years, she has 11 intermediate stations.
The station connected the city of Hefei (the administrative centre of Anhui province, eastern China) to Shanghai. The line will be one of the segments of similar highway link between Beijing and Shanghai, the construction of which is planned to be completed by the end of this year.
Quantum cryptography is based on the principles of particle behaviour in which it is impossible to measure one of the parameters, without distorting the other. If an e-mail to encode the light of these properties, and pass through the network, any unauthorized attempt to connect and see this information will change it. As a result, the offender will not be able to read an intercepted message, and the recipient will be able to tell by the amount of noise in the communication channel that was subjected to an attack.
Note that in August this year, China has carried out a successful launch of the first experimental satellite of the world for quantum communications. One of the main tasks of the unit "Mo-tse" will be the implementation of quantum information transfer and the establishment of a secure communication channel between China (Beijing) and Europe (Vienna) is completely invulnerable to hackers.