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China demonstrates Quantum Encryption with Video Call

Article is sparse on technical details, but suggests that it was primarily used for initial key exchange before a conventional VPN was established.

For the demo, Pan’s team first established a connection and generated a secure key between a ground station in Xinglong and the Micius satellite as it passed overhead, orbiting about 500 kilometers above Earth. From Xinglong, the key traveled through the fiber to Beijing, where the Chinese Academy of Sciences is based.

Next, the Chinese team waited for Micius to pass over Vienna, where their collaborators at the Austria Academy of Sciences were waiting to also receive the key from the satellite. Then, with the keys in hand, the groups initiated a video conference and used those keys to encrypt the video data through a standard VPN protocol.

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While the elite use quantum cryptography secured video chat, the majority of Chinese citizens successfully had their communications monitored. This is a balanced society.

I can only assume that satellite Micius will also be the first satellite to attempt a Quantum MitM attack.

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The problems of a world ruled by money, not by equality or law.
Very interesting in terms of technology, very bad in terms of society.

Hmm what is “quantum” about this? Did they use entangled pairs to transmit data to and from the satellite?

Last I heard they were having difficulty getting anything from what was essentially noise.
Either it seems like entalgement is still quite short range and very noisy, or they are obscuring how good it really is!

"Nie Jiming, a quantum researcher at the CAS, said quantum communication uses subatomic particles such as photons-individual particles of light-to send data using quantum mechanics. This creates “the most secure” connection because those particles cannot be destroyed or duplicated, and eavesdropping can be immediately detected."
From http://www.trunews.com/article/quantum-internet-is-almost-here
While I doubt the general public will see a “quantum internet” historically unsecure comms can be bad like with jn25 and blechley park and ultra.
The satellite uses Spooky Action :slight_smile:
http://www.sciencemag.org/news/2017/06/china-s-quantum-satellite-achieves-spooky-action-record-distance

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How does that differ from regular ‘fibre’ optics? You have either the wave model or the quantum model, and photons are the the means from which say a CMOS sensor captures an image. When taking a photo with DSLRs for example (or your phone) we don’t go around saying “oh hey, here’s my photo of photons”.

Suppose they chose a particular wavelength and fired photos at that exact wavelength, aren’t we then basically taking about firing a laser (of photos?)

Hmmmm…

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spooky action is like what we used to call PFM or Pure Flipping Magic.
Take 2 photons
entangle them (way beyond my brain and wallet )
Then separate the photons by allot of miles
mess with one and the other photon somehow does the same thing
No one knows why or how, but you can use this property to communicate.
These guys explain it better then me

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Wow seems way more complex than I thought. The old split up a pair, tweak one and watch the other change isn’t what is going on here.

The satellite is generating entangled photon pairs. Somehow these are organised into keys. One photon of each pair is kept, the other sent down to a ground station. These keys are then used to fire up a VPN over traditional infrastructure.

While they mention a third photon can interact which each entangled one sent down, effecting a change int he one at the satellite, this isn’t used in any form currently.

The article mentions it’s still hit and miss, and only working slightly better than chance. There is the idea that spooky action at a distance happens instantaneously (faster than c), but only because no information is actually transmitted…

Quantum physics is weird and I don’t understand it. Still, you gotta start somewhere! This is the sort of stuff that needs to be happening more often.

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Wow mind blown. And my guess about lasers was spot on. I did a bit of quantum mechanics at Uni, but that was a decent while ago.

The most fun I had was designing a ‘doped’ transistor. Plank’s constant keeps coming to my mind and I somewhat recall lectures on Fermi-levels; that’s how I recalled the stuff on Photons

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Pretty much this, but you got one important detail wrong:

You use this property to NOT communicate. The major advantage of quantum technology is that if anyone were to evnn read one qubit the other one reacts - as you stated. This property is however used to detect eavesdropping, i.e. prevent unauthorized communication. You actually quoted this:

Spooky action at a distance cannot be used to transmit information because the reaction is instantaneuous and would thus violate general relativity - nothing travels faster than the speed of light.

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Kinda like the last paragraph
"Eventually, quantum teleportation in space could even allow researchers to combine photons from satellites to make a distributed telescope with an effective aperture the size of Earth — and enormous resolution. “You could not just see planets,” says Kwiat, “but in principle read licence plates on Jupiter’s moons.”"

Ok I drive a truck fer a livin but these guys think it kinda does :slight_smile:


Also C may be a variable and not a constant
http://www.naturalphilosophy.org/site/nickpercival/2016/08/25/the-speed-of-light-varies-over-time/
https://www.newscientist.com/article/dn6092-speed-of-light-may-have-changed-recently/

Heck last I checked they were still scratching their head on how a high red shift quasar could be found in a low red shift galaxy. But that was a few years ago and way way tangential.

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Ah that’s the crucial detail I missed. Still messes with the mind a bit.

I know my head hurts :slight_smile: Allot
I had to go to the lounge to recover

The effect of the quantum entanglement appears instantaneous or at least faster than light however no information is being transmitted, so at least by our current understanding it can’t be used to create a faster than light communications system.

I think the best way I heard it described was that particle A isn’t talking to particle B but two observers are seeing the same thing happening at the same time in two different places.

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