>“The satellite’s two-year mission will be to develop

>>8275134
>hack-proof
hah

>>8275134
>and at speeds faster than light
topkek, someone didn't get the difference between causality and locality in QM

>>8275146

Yeah, probably the journalist, since they're generally the ones responsible for stupid or lying science headlines.

>>8275134
I didn't get how this is gonna work. At all.

>>8275138
What's funny about that?
https://en.wikipedia.org/wiki/Quantum_key_distribution

File: top nep.png (401KB, 500x708px) Image search: [Google]

401KB, 500x708px

>hackproof
>faster than light

>>8275288
>Quantum key distribution is only used to produce and distribute a key, not to transmit any message data.
it's even right there in the name

I can see where they're coming from: at speeds faster than light in a fiber optic cable.

>>8275242
It's "quantum encryption". As a rule, when someone says "quantum X", they're labelling a weird quantum phenonenon that has some vague relation to X, but definitely isn't X as you normally think of it.

Rather than being a kind of encryption, quantum cryptography is a means of establishing a secure physical link across unsecured space.

Entanglement is used to generate a single photon with a significant value for one of two measurable properties. You have to choose which of the two properties to measure, because measuring either one consumes the photon, and measuring both simultaneously is impossible.

So two stations with a shared secret can choose which property to hide their data in, in an unpredictable pattern. Someone who intercepts photons won't know which property to measure, so will randomly either get a bit that's part of the message or one that isn't.

This can be used, in theory, to prevent someone with the power to intercept transmissions from collecting any of the transmitted information.

In practice, there are many complications and potential weaknesses.

>>8275333
That's a dumb line. The same methods can be used to send message data, but it's called "key distribution" because the fact that you can expand your shared secret is the more significant feature.

>>8275940
What kind of machine do you need to do this?

>>8276071
>The same methods can be used to send message data
but if you have a securely distributed key there's no reason to. you could shout your encrypted message from the other side of a crowded street if you wanted

>>8276075
...except then you're giving away the fact that you're communicating messages rather than just distributing keys.

It's better if attackers can't tell the difference, though obviously there are many situations in which you prefer to encrypt messages rather than use a secured quantum link.