Communications encrypted with the use of quantum-entangled photons:
Chinese satellite to begin quantum communications experiments
China launched a pioneering satellite mission Monday to prove the viability of quantum communications from space, an innovation that could led to a worldwide network to transmit hack-proof messages among military forces, financial institutions and multinational companies.
The concept calls for an instrument aboard the newly-launched satellite to generate a pair of photons, tiny sub-atomic particles of light. Then a high-power telescope on satellite will beam one half of the pair to ground stations in China and Europe.
The photons will be in a quantum state, meaning their properties depend on the other. Quantum entanglement has never been proven over such great distances before.
Scientists on the ground will use the photons to create a secret key, allowing messages to be exchanged between Europe and China via conventional networks like the Internet. The key is needed to break the encrypted code.
The satellite can then establish a quantum cryptographic key, for example, between China and Austria to be the first worldwide secure quantum communication, Zeilinger said in an interview with Spaceflight Now.
The benefit of quantum communication is in its security. According to a report by Nature in July, the key is derived from the polarization of a string of photons, and any attempt to hack or tinker with the messages is immediately detectable.
Quantum Entanglement Simplified - Microscopic Universe