Post-Snowden China looks to 'hack-proof' quantum communications

Ten months after Edward Snowden revealed the extent of the US' global surveillance programme, China started to build the world's longest quantum communications network, transmitting signals some 2,000km from Beijing to Shanghai.

Pan Jian-Wei, a quantum physicist with the University of Science and Technology of China who heads the project, told the journal Nature in April that the network would "provide the highest level of protection for government and financial data."

China is plans to launch the world's first quantum satellite, the Chinese Quantum Science Satellite, in 2016, Pan said. It will test how to teleport quantum particles from the space to the earth.

China is not alone doing this. A Switzerland-based start-up, ID Quantique, last October installed a 650km quantum link in the US, media reported. It is now looking to secure funding to build a network linking all major US cities, which could exceed 10,000km.

Quantum communication, which transfers information by using a technology called quantum key distribution, is the holy grail of data encryption. Theoretically, it is impossible to hack.

In quantum mechanics, connections are made between two points when photons of light become entangled. This creates an encryption key that can be used to send the message through normal channels.