Satellite beams 'unbreakable' cipher from space


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If you are closely following the Quantum advancements, you would have come across the news of Chinese satellite "Mozi" launch in August, 2016. With this successful launch, Chinese proved they are way ahead (atleast per the public information) and are taking quantum-communication seriously. Mozi is dedicated to understand and test the phenomenon of Quantum entanglement. Mozi, a 500Kg satellite derived it's name from the 5th century BC chinese scientist and is motivated to perform Quantum Experiments at Space Scale (QUESS). It constitutes,

  1. Quantum Key communicator
  2. Quantum Entanglement emitter
  3. Entanglement source
  4. Processing Unit
  5. Laser Communicator

Today, August 10th 2017, Chinese scientists successfully became the first to perform the quantum key distribution from satellite to the ground as Xinhua reports. This achievement is a milestone in the quantum progression and is applauded by scientific community & NATURE journal reviewers! In the past, researchers reported in the Science,

... by beaming photons between the satellite and two distant ground stations, they have shown that particles can remain in a linked quantum state at a record-breaking distance of more than 1,200 kilometres.

In reference to the cutting edge security, Quantum communication is "secure" because any interference is detectable. Once intercepted or measured, the quantum state of the message will change, and the information being intercepted will self-destruct! Pan Jianwei, a lead scientist of QUESS and an academician of the Chinese Academy of Sciences (CAS), said,

An eavesdropper on the quantum channel attempting to gain information on the key will inevitably introduce disturbance to the system, and can be detected by the communicating users.
The communication distance between the satellite and the ground station varies from 645 kilometers to 1,200 kilometers, and the quantum key transmission rate from satellite to ground is up to 20 orders of magnitude more efficient than that expected using an optical fiber of the same length.

Thus, in the future using quantum entanglement, two (2) parties can exchange secret messages by sharing an encryption key encoded in the properties of entangled particles. This mission can be the catalyst, for early adoption of global quantum communication network.

While this is a war of nations, US and China investing heaviliy in Quantum research and implementations; it surely is a win for science!

References and attributions,

  1. Hacker News:
  2. Xinhua News:
  3. NASA Spaceflight: