Three countries have accepted China's invitation to join a super-secure quantum communications network that will ultimately cover the planet, altering global data sharing, when scientists launch the first quantum satellite later this year.

While dedicated to quantum science experiments, the satellite serves as evidence that China is leading the world in quantum cryptography, said Pan Jianwei, a leading quantum expert with the Chinese Academy of Sciences.

"We wrote to the ground stations of Italy, Canada and Austria to express our willingness to connect them to our network and have received positive responses," said Pan, who leads an international team in quantum research at the University of Science and Technology of China.