

Multipartite Einstein-Podolsky-Rosen Steering may lead to ultra-secure internet - houseofshards
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.111.250403

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akie
A dummy explanation for non-physicists like me (from
[http://www.swinburne.edu.au/engineering/caous/news_and_event...](http://www.swinburne.edu.au/engineering/caous/news_and_events/mulitipartite%20EPR%20steering%20paper.htm)):

"Einstein's reservations about quantum mechanics were encapsulated in the 1935
Einstein, Podolsky, Rosen paradox, which highlighted the theory's strange
nonlocality. In this paper, we give theoretical proof that special quantum
states allow Einstein's nonlocality to be genuinely shared among many
observers, regardless of the spatial separation between them. These states
possess a property (which Schrodinger called "steering") that not all quantum
entangled states have, and may provide unprecedented security for a future
quantum internet.

Suppose Alice has a secret message to transmit. Alice may use the states to
send multiple parties a quantum encryption key, or, if the message is highly
important, she can "secret share" i.e. distribute the key among the receiving
parties, so they must collaborate to decipher the message. The important new
feature is that (unlike ordinary entanglement) Einstein's nonlocality cannot
be faked by classical means without Alice's collusion. Assuming her station is
secure, this enables detection not only of hacking attacks during
transmission, but of dishonest receivers or sabotage of devices at receiving
stations. We show that the special states can be created in different forms so
they are useful for messages carried either as optical amplitudes or as
photonic qubits."

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trurl42
The content of the article is freely accessible on the arXiv:

[http://arxiv.org/abs/1212.2270](http://arxiv.org/abs/1212.2270)

And no, this will not lead to ultra-secure internet, which also isn't even
mentioned in the article.

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crashandburn4
Exactly, I find it ridiculous that someone or other adds these titles
somewhere and no-one disputes them even when the papers have very little to do
with the title whatsoever.

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Loughla
It's not ridiculous. It's the first rule of all internet forums.

No one reads the articles.

~~~
crashandburn4
True, so what _should_ happen is that the title summarizes and maybe provides
additional data about the content of the article rather than says something
else, I accept that that doesn't happen but I also say it's ridiculous. :)

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marcosdumay
Just to make it clear, the usual caveats of quantum cryptography apply:

1 - It requires direct physical links between the involved parties.

2 - It does not provide authentication, and thus is subject to man in the
middle attacks.

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coldcode
I have to admit I understood almost nothing of the abstract.

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clef
We might use it for teleportation in 500/600 years.

~~~
btilly
No. Quantum entanglement does not allow for transmission of information faster
than light. And therefore does not allow you to suddenly move objects from one
place to another.

What it does allow for is the synchronization of random data between two
places faster than light. So two receivers can securely find themselves in the
possession of a shared encryption key, that can then allow them to send
information in a way that intermediates can't intercept.

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hellrich
Traveling with the speed of light seems nice enough, yet I don't understand
how the results would help with any kind of teleportation.

~~~
btilly
They don't allow teleportation. That's my point.

