The breakthrough was reportedly reached by China’s Quantum Experiments at Space Scale (QUESS) satellite, nicknamed “Micius” after a 5th century BC Chinese philosopher. The satellite was launched in August 2016, with the US Pentagon calling it a "notable advance in cryptography research".
Xinhua News Agency today announced that experiments conducted by the satellite had been successful, managing to send quantum keys to ground stations in north China's Hebei Province, and northwest China's Xinjiang Uygur Autonomous Region. The distances between the satellite and these stations varied between 646 km and 1,200 km, and the transmission rate is reported to be up to 20 times more efficient than using optical cables of the same length.
China has transmitted an “unbreakable” quantum code from a satellite to the Earth’s surface, in what Chinese state media is calling the foundation for a “hack-proof global quantum communications network”.