10-Aug-2017: China uses a quantum satellite to transmit potentially un-hackable data

China has demonstrated a world first by sending data over long distances using satellites which is potentially unhackable, laying the basis for next generation encryption based on so-called quantum cryptography. Last year, China launched a quantum satellite into space. Using this satellite, Chinese researchers at the Quantum Experiments at Space Scale (QUESS) project, were now able to transmit secret messages from space to Earth at a further distance than ever before.

The technology is called quantum key distribution (QKD). Typical encryption relies on traditional mathematics and while for now it is more or less adequate and safe from hacking, the development of quantum computing threatens that. Quantum computing refers to a new era of faster and more powerful computers, and the theory goes that they would be able to break current levels of encryption. QKD works by using photons — the particles which transmit light — to transfer data.

QKD allows two distant users, who do not share a long secret key initially, to produce a common, random string of secret bits, called a secret key. Using the one-time pad encryption this key is proven to be secure to encrypt and decrypt a message, which can then be transmitted over a standard communication channel.

The encryption is “unbreakable” and that’s mainly because of the way data is carried via the photon. A photon cannot be perfectly copied and any attempt to measure it will disturb it. This means that a person trying to intercept the data will leave a trace. Any eavesdropper on the quantum channel attempting to gain information of the key will inevitably introduce disturbance to the system, and can be detected by the communicating users. The implications could be huge for cybersecurity, making businesses safer, but also making it more difficult for governments to hack into communication.