U.S. Department of Energy Unveils Blueprint for the Quantum Internet
energy.gov
energy.gov
* It is orders of magnitude slower than normal data transmission.
* The range is limited.
That makes it suitable for key exchange between two switches connected by a fibre. However Diffie-Hellman key exchange does this perfectly well already, if you need it. Also quantum encryption can't survive going through any kind of forwarding other than an optical circuit switch, so as soon as you do anything higher level you need to decrypt and re-encrypt the data, breaking the physical guarantees.
When you look at the security threats to modern communication, physical taps are way down the list. Security is already built on the idea that the network is compromised, so end-to-end encryption is already the norm. Adding quantum encoding buys you nothing.
That starts to make more sense.
However, the title is... a tad ambitious. To the best of my understanding, the "quantum internet" so far has managed to transport 1 bit across 26 miles and it's not clear at which speed (yeah, I know it's theoretically above the speed of light, but I'm not sure about the specifics here) or which infrastructure was needed (apparently, fiber cable, in which case it's not entirely clear to me what makes this quantum).
I thought superluminal communication is considered impossible.[0]
[0]https://en.wikipedia.org/wiki/Faster-than-light_communicatio...
At least, that's how it _could_ be. Not sure how it is actually.
The communication relies on an exchange of information via classical means so the relativistic bound holds.
https://en.wikipedia.org/wiki/No-communication_theorem
All quantum cryptography does is make the photons you send tamper-evident. You can use it to establish a shared key that can't be snooped on, and then use that to communicate using ordinary symmetric cryptography. Of course, asymmetric crypto does this fine, so unless you are very suspicious of modern asymmetric crypto you probably don't need it.