Why the Chinese Quantum Satellite Test is Important
A Chinese experimental satellite, called QSS (Quantum Science Satellite), will test a quantum encryption scheme that aims to improve the security of satellite communications. The satellite will test a technique called quantum key distribution to make encrypted signals much less hackable. The scheme exploits the quantum principle of entanglement and the quantum principle that measuring the state of a quantum object changes its state. Entangled photons, composing the encryption key, are simultaneously transmitted by the satellite to receivers on Earth. Any attempt to observe the photons while in transit will alter the quantum state. If the quantum states of the photons match at both receivers, then the parties know the encryption key is secure. If the states do not match, then it is possible someone has attempted to observe the photons composing the encryption key.
The U.S., China, and Europe are already using Quantum key distribution on fibre-optic networks. However, today's technology limits the distance of these networks to a few hundred kilometers as it becomes difficult to reliably match the quantum state of photons over longer distances. Even though QUESS will be located 1,200 km away from the receiving stations, photons travel more easily through space.
Why this news is important
The team testing QSS includes researchers in China, Australia, Italy, and Germany. If the experiment is successful, the new technology could lead to the deployment of a satellite constellation, within 10-15 years, that can share ultra-secure (spy proof) quantum encryption keys anywhere in the world.
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