Quantum Network Joins Four People Together For Encrypted Messaging (newscientist.com)

An anonymous reader shares a report: The quantum internet is starting small, but growing. Researchers have created a network that lets four users communicate simultaneously through channels secured by the laws of quantum physics, and they say it could easily be scaled up. Soren Wengerowsky at the University of Vienna and his colleagues devised a network that uses quantum key distribution (QKD) to keep messages secure [the link is paywalled]. The general principle of QKD is that two photons are entangled, meaning their quantum properties are linked. Further reading: Nature.

Comments

First received message..

[jimtheowl]

Hello, I am Quantor Prince and have been stranded in entanglement after secret experiment from my captors. I have made causality agreement with guard who is willing to free and not free me for the sum ..

Re:First received message..

[Anonymous Coward]

Hello, I am Quantor Prince and have been stranded in entanglement after secret experiment from my captors. I have made causality agreement with guard who is willing to free and not free me for the sum ..

Hey! I am willing to and not to pay your sum!

Coincidence?

[chrism238]

ARPAnet also started with just four nodes: https://www.scientificamerican...

Re:Coincidence?

[Actually, I do RTFA]

Probably a coincidence. ARPAnet made a triangular ring, and then had one more node off that. That's enough to test routing, etc. (A connects to B,C; B connects to A,C; C connects to A,B,D). Therefore, they can make sure A->B doesn't get confused and go A->C->A (repeat) ->B and A->D can make the hops. So,. useful for testing.

This quantum nodes were connected in a ring, all four nodes connected each of the three others. The limit seems to be based on the fact that they had 12 multiplexed channels. I notice that 12 connections (if unidirectional) is the number needed to connect all 4 nodes to each other. (2 connections -> 2 nodes, 6 connections -> 3 nodes, 12 connections -> 4 nodes)

Re:Will it still exist ...

[GoTeam]

Does it change state when someone does look at it?

Be careful

[nospam007]

You remember what happened, when Alexander Graham Bell added a third phone to his 'network'.
He was relaxing in his bath when the phone rang. Wet like a dog he hobbled to the phone just do detect the first ever 'wrong number'.

..strange

[kiviQr]

It said I had a message. I opened it and it wasn't there!?

I knew this because

[Oswald McWeany]

I knew this because my quantum ai blockchain device from Elon Musk had already told me.

Pointless use case

[WaffleMonster]

At the end of the day this is all still rooted in symmetric encryption. Given todays cost and capability of storage it's just as easy to pre-fill a lifetime supply of "messaging" or voice communications in an OTP pool as it would be to initially provision secret keys in quantum modem doodads to support quantum encryption.

Only OTP pools are way cheaper and easier.

Where quantum crypto would be useful is in securing high bandwidth (multi-gigabit) data links.

Re:Pointless use case

[WaffleMonster]

Right. You could fill a 10-TB HDD with your OTP and physically give it to someone and be assured of secure communications with them effectively forever,

Honestly gigabytes would be more than enough for text and voice communication. 128 GB sd cards are like $20.

but classical one-time pad exchange still has all of the same flaws that it's been known to have for the last eighty-odd years, namely the lack of transport security of the OTP itself

No it's the same exact problem either way. Whether you are guarding OTP or an initial secret for quantum keying the total security of the system hinges upon that secret information in whatever form it happens to reside in being successfully guarded. Quantum in no way changes that.

itself and the difficulty of scaling to many people.

I don't understand the basis for such schemes being limited to quantum and all the relevant details are pay walled. There are numerous schemes that can be employed to enable via centrally trusted agents to facilitate communications amongst peers.

Re:Pointless use case

[WaffleMonster]

Quantum encryption doesn't need any provisioning. The measurement basis can be sent unencrypted on a classical channel.

Some sort of authentication on that classical channel is still a good idea to make sure that the encrypted connection isn't with a man-in-the-middle.

I think I understand now:

1. You don't need to provision.
2. If you don't provision it won't be secure.
3. Security is the whole point of quantum key distribution.

Re:Pointless use case

[WaffleMonster]

But the quantum key doesn't need a quantum secret. Both parties generate online an OTP, using a public classic channel, and a quantum one.

The static test on the resulting bit sequence can be used to certify that no
third party has intercepted the OTP.

The point of quantum cryptography is to provide secure communications.

There is no such thing as secure communications without a means of authenticating communicating peers. There can be no security if you don't know who you are talking to in the first place.

Re:Government will not allow it

[jellomizer]

Or perhaps they will, and our own paranoia will keep us in our place.
Why bother putting the resources in spying on us when it is much easier to make us think that we are being spied on.

Non-paywalled article source, please?

[Rick Schumann]

Article is behind a paywalled and I can't find a non-paywalled source, thanks so much for that.

Bullshit

[sexconker]

No one has ever been able to detail how entangling particles helps anything with regards to encryption or key sharing.

If you pass out entangled particles to a set of people, all you gain is the ability to know the state of their particle as soon as you look at yours. (And you could have done that at the time you distributed the particles - there's no FTL transfer of information, and no breaking of causality.)

If you are able to securely pass out entangled particles, you are able to securely pass out convention particles describing a conventional key.
If you are not able to securely pass out entangled particles, you're not gonna do much, are you?

Re:Bullshit

[WaffleMonster]

I don't think this is accurate. The question is always how do you KNOW that the particle wasn't intercepted somewhere along the line?

Quantum doesn't tell you this in a vacuum. Only when combined with cryptographic operations involving guarded secrets can the integrity of the channel be established.

With quantum key exchange, you know if your key was compromised along the path. If it was, don't use that key. With conventional key exchange, you have zero way of knowing if someone put a splitter in the line somewhere, and intercepted your key.

No. There is nothing that can't be done using conventional cryptography that quantum brings to the table. Numerous keep agreement protocols based on symmetric keys exist which perform the exact same function with no known weaknesses.

The only advantage of quantum are certain immunities from future compromise of cryptographic algorithms but even that isn't absolute.

So all that's possible with quantum key exchange is for the attacker to prevent you from exchanging keys

It can also reveal information about the nature of the guarded secrets used to authenticate the quantum channel.

Re:Bullshit

[WaffleMonster]

If you pass out entangled particles to a set of people, all you gain is the ability to know the state of their particle as soon as you look at yours. (And you could have done that at the time you distributed the particles - there's no FTL transfer of information, and no breaking of causality.)

If you are able to securely pass out entangled particles, you are able to securely pass out convention particles describing a conventional key.
If you are not able to securely pass out entangled particles, you're not gonna do much, are you?

The point of quantum crypto is disconnecting future keys from observable reality.

Assume an adversary was able to record all communications and they kept them forever.

With the information collected they may eventually find a way to derive initial encryption keys either by stealing, brute force or leveraging cryptographic weaknesses and in-turn use that information to help facilitate future breakage of key rotation/management schemes designed to reinforce initial encryption keys.

What quantum crypto does is provably break the link between initial key and future keys so even if an adversary is recording everything and manage to break the initial key they are fundamentally denied the ability to break follow on keying by leveraging any data classically communicated based on previous knowledge of existing keys.

The only advantage quantum provides vs. normal cryptography is it guards against unknown cryptographic weaknesses. In the absence of such weaknesses quantum crypto is totally worthless.

Phrasing!

[SuperKendall]

Quantum Network Joins Four People Together

That headline summary sounds like a bad SyFy reboot of The Fly.

With Stan Winston gone I'm not sure it could be done properly.

Re:Phrasing!

[Locke2005]

Quantum Human Centipede?

Re:Will it still exist ...

[vtcodger]

Does it change state when someone does look at it?

No, but it kills half the cats within 100 meters of any component of the network

Re:What happened?

[jimtheowl]

You do not have to be an 'urban sophisticate' to believe in the scientific method.

Re:What happened?

[Seven Spirals]

I'm not trolling I'm asking... How much physical evidence for quantum entanglement is there? I gotta admit that it does sound like bullshit, but then again I'm sure airplanes would sound like bullshit to the Romans. Wouldn't quantum entanglement also give you instant communications (before it gave super fast CPUs) by altering one entangled bit say in Los Angeles while someone else gets the signal in Cairo? I haven't seen anything to indicate that the idea works at all for any purpose. It's been talked about for years. Quantum Computing is sounding a lot like "Flying Cars" and "Better Batteries". I know both are possible, but I sure don't see evidence that it's gonna happen. Then again, I'm not a Quantum researcher.

Researchers have created a network ...

[grep -v '.*' *]

Researchers have created a network ... and could easily be scaled up. ... devised a network that uses quantum key distribution (QKD) to keep messages secure [the link is paywalled].

Lawyers created secure networks that decades ago. If you don't pay ("the link is paywalled") you can't see the message. Or if you DO see, you have to poke your eyes out. (You've seen those email trailers from some companies: intended for; if not then you are restricted from [breathing] ...)

Besides, TERRORISTS, and "Here's a $5 wrench, go find out what he knows."

Quantum Secrets

[mentil]

The only way four people can keep a quantum secret is if three of them are dead, or a quantum superposition of alive and dead.
The death certificates will say "Cause of death: wavefunction collapse."

So, um...

[Locke2005]

What's the porn like on that network?

Re:paywall paywall paywall

[Locke2005]

Obviously not the brain, pretty sure that's already gone missing!