[shalg]

There are exactly 2 reasons we might want quantum networks.

1. 100% secure communication channels (even better we can detect any attempt at eavesdropping and whatever information is captured will be useless to the eavesdropper)

2. Building larger quantum computers. A high fidelity quantum network would allow you to compute simultaneously with multiple quantum chips by interfacing them.

The thing that makes quantum networking different from regular networking is that you have to be very careful to not disturb the state of the photons you are sending down the fiber optics.

Im currently doing my PhD building quantum networking devices so im a bit biased but I think it’s pretty cool :).

Now does it matter I’m not sure. Reason 1 isn’t really that useful because encryption is very secure. However if quantum computers start to scale up and some encryption methods get obsoleted this could be nice. Also having encryption that is provably secure would be nice regardless.

Reason 2 at the moment seems like the only path to building large scale quantum computing. Think a datacenter with many networked quantum chips.

[nativeit]

> 100% secure communication channels (even better we can detect any attempt at eavesdropping and whatever information is captured will be useless to the eavesdropper) chips. A few follow up questions:

1. What is it about quantum computers that can guarantee 100% secure communication channels?

2. If the communications are 100% secure, why are we worried about eavesdropping?

3. If it can detect eavesdropping, why do we need to concern ourselves with the information they might see/hear? Just respond to the detection.

4. What is it about quantum computing that would make an eavesdroppers’ overheard information useless to them, without also obviating said information to the intended recipients?

This is where the language used to discuss this topic turns into word salad for me. None of the things you said necessarily follow from the things that were said before them, but rather just levied as accepted fact.

[SAI_Peregrinus]

1. Nothing. Quantum Key Distribution is what they're talking about, and it still requires P!=NP because there's a classical cryptographic step involved (several, actually). It just allows you to exchange symmetric keys with a party you've used classical cryptography to authenticate, it's vulnerable to MITM attacks otherwise. So you're dependent on classical signatures and PKI to authenticate the endpoints. And you're exchanging classical symmetric keys, so still dependent on the security of classical encryption like AES-GCM.

2. Because they're not 100% secure. Only the key exchange step with an authenticated endpoint is 100% secure.

3. Eavesdropping acts like a denial of service and breaks all communications on the channel.

4. It makes the information useless to everyone, both the eavesdropper and the recipients. Attempting to eavesdrop on a QKD channel randomizes the transmitted data. It's a DOS attack. The easier DOS attack is to break the fiber-optic cable transmitting the light pulses, since every endpoint needs a dedicated fiber to connect to every other endpoint.

[foota]

Sorry, but I think the way you're phrasing this implies a burden on them to explain well understood and widely accepted principles of quantum physics that you seem to be implying are pseudoscience.

This seems like a decent overview if you want to learn more: https://www.chalmers.se/en/centres/wacqt/discover-quantum-te....

[nativeit]

I feel like most of your answer was just re-stating the question. I’m happy to admit that’s almost certainly a mix of my ignorance on the topic at hand, and I have been primed to view the discussions surrounding quantum computing with suspicion, but either way, that’s the way it reads to this layperson.

[thesz]

What is the difference between channel error or distortion and eavesdropping?

[staunton]

For eavesdropping, there is someone there who cares about what you're sending and is successfully learning things about it.

[chatmasta]

If studio execs have their way, Quantum DRM will be the killer use case…

[autoexec]

Jokes on them, we'll just end up creating and using quantum pirating systems or even the dreaded Quantum Analog Hole to evade it.