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Dr Jennewein’s proposal is for Alice to beam polarisation-encoded photons to a satellite. Once she has established a key, Bob, on another continent, will wait until MK bags satellite passes over him so he can send some more photons to it to create a second key. The satellite will then mix Michael Kors Handbag keys together and transmit Michael Kors Purse result to Bob, who can work out Michael Kors Satchel first key because he has Michael Kors Shoulder Bag second. Alice and Bob now possess a shared key, so they can communicate securely by normal (less intellectually exhausting) terrestrial networks. Dr Jennewein plans to test Michael Kors Tote idea, using an aircraft rather than a satellite, at some point during Michael Kors Wallet next 12 months.

An alternative, but more involved, satellite method is to use entangled photon pairs. Both Dr Zeilinger’s and Dr Ling’s teams have been trying this.

Entanglement is a quantum effect that connects photons intimately, even when they are separated by a large distance. Measure one particle and you know Micheal Kors 2013 New Style Handbags state of its partner. In this way Alice and Bob can share a key made of entangled photon pairs generated on a satellite. Dr Zeilinger hopes to try this with a QKD transmitter based on Michael Kors Outlet 2013 International Space Station. He and his team have been experimenting with entanglement at ground level for several years. In 2007 they sent entangled photon pairs 144km through Wholesale Micheal Kors Handbags air across Michael Kors Outlet Online Canary Islands. Dr Ling’s device will test entanglement in orbit, but not send photons down to Earth.

If this sort of thing works at scale, it should keep Alice and Bob ahead for years. As for poor Eve, she will find herself entangled in an unbreakable quantum web.