Very good explanation of QKD! The use of photon polarization in these protocols is called a Discrete Variable QKD, it has some downsides like requiring very good single-photon detectors, so nowadays there's a lot of research on Continuous Variable QKD (CV-QKD), which can use the very Electric Field of the signal as the quantum variable, the best part is that it's been shown to work on regular telecommunication devices, which is much more attractive for companies. I did some research in this field and it does seem like a complete CV-QKD system is almost achieved, the major problem is the speed, which is much slower than conventional communication due to the high complexity of the reconciliation protocols.

hooray! another IM video! I’ve been eagerly awaiting it.

the kind of video I have to watch again over a few weeks/months, I've missed that so thank you sir.

Highest quality content. Thank you !

This video is so powerful. Keep up the good work!

Perfectly put, thank you so much

He has returned to drop another nugget of knowledge upon us!

Hey @imporable matter, will u do a sparc video in the future ? I saw it had a Q of 11 but I'm not a fusion scientist so I came here

New IP video and I drop everything!!

Wouldn’t the atmosphere or molecules in a fibre optic cable mess up the superposition?

Wouldn’t this mean that you’re limited to the distance of a single fiber optic? If all the security comes from not being able to clone the photons, no repeaters are possible, the best you can hope for is connecting to an intermediate node and form a sort of “chain” of nodes that go from one end to the other. But now every single one of these nodes is a critical part of your security. Given that the threat to current technology (Quantum Computers) are nowhere near what they’d need to be an actual threat, this looks like a great source for academic papers with very little practical benefit.

@ImprobableMatter

5 ай бұрын

While I agree that totally trustless communications between, say, London and San Francisco would be impossible directly, it's possible to distribute keys up to 10s of km along fibers. I think this would still be useful as an average user can communicate with a trusted party like Visa or Google. Then there is also communication with satellites.

@theondono

5 ай бұрын

@@ImprobableMatter But that’s precisely my point, I don’t need to trust any of the intermediaries in the internet with our current technology. Future proofing our communications for fear of a technology that doesn’t exist, and has shown little progress sounds far from practical. Even *if* this solution could work without trusted intermediaries, the added cost and risk of deploying new tech would have to be weighed. Again, I’m not saying this isn’t interesting (it is!), it’s just that in every time I get into this discussion with my network engineering friends, I don’t see it happening any time soon.

@ImprobableMatter

5 ай бұрын

@@theondono The danger is a man-in-the-middle attack if large prime numbers could be factorized (e.g. with Shor's algorithm on a quantum computer). I'm also not saying that's imminent, but certainly possible.

@MikeKrasnenkov

5 ай бұрын

No cloning theory only forbids creating two particles with same state from one. Therefore it is theoretically possible to envision a device that will consume a photon and reemit it without gaining knowledge about it’s state (thus guaranteeing no eavesdropping) using some sort of quantum process with intermediate particles or something like this, which can be what facilitates switching and repeating for long distance connections.

BB84 (7:00) basis exchange ONLY AFTER information bit HAD BEEN sent... even if both knew their basis ahead of transmission. ( just my 2c.. no expert.. I first confused with thought what if middle man got all those basis and measure it... but then there is nothing to measure since all photons had been sent... maybe I am just slow learner.. lol) .. great explanation... I knew nothing before .. now a little.. lol

Could we get a future video about public key encryption?

@ImprobableMatter

5 ай бұрын

It would probably be a livestream if at all. I'll get a blackboard and go through RSA as an example.

@andrewnelson4148

5 ай бұрын

@@ImprobableMatter I don't understand how we would do asymmetric encryption with one and zero. Will it be explained at that level?

I have a couple of quesitons: 1.Is this type of encryption theoretically unbreakable? 2.When the satellite recorded the signal sent to it by China, shouldn't that signal be stored in the satellite's memory, a memory that can be read. Thanks!

@qwoop6351

5 ай бұрын

1. More than encryption this is communication, a way to handle key exchanges without evasdropers or Man in the middle stuff. However it enables use of One time pad remotely and safely, which would in effect be stronger than current public/private key stuff due to lacking the (very elaborate) mathematical tells. 2. Yeah but as explained in the example on the video with the perfect photon replicator, even if someone is able to read the memory/clone the messages you would still be able to deal with it

@ImprobableMatter

5 ай бұрын

Yes, it is unbreakable theoretically. Yes, you are establishing a link to the satellite, so if someone could physically intercept the orbiting satellite they might be able to hack it somehow.

Hell yhea new video

In the E91 method, how do the photons get entangled in the first place?

@ImprobableMatter

5 ай бұрын

One way is to take a laser, which produces photons and then use a crystal which converts each of them into two other photons with half the energy. In that process, each pair produced are entangled. In reference [7] in the description, they use a β-barium-borate (BBO) crystal.

What is the software you are using for creating this content like the animation and white-broad?

@ImprobableMatter

3 ай бұрын

The vast majority of graphics are made using Inkscape. I export multiple layers as images with each of the objects, like photons in this case, and then move them around in the animation software. Any free or commercial video editing software can move, fade, rotate and so on if you have images.

@ThePerceivEdLearningHub

3 ай бұрын

Thank you!!

Sorry but this is quite confusing at 8:15 , why on earth will bob receive a diagonal to right photon, if the one sent by the eavesdropper is vertical, surely he should receive a vertical photon sent by the eavesdropper?

@ImprobableMatter

Ай бұрын

Yes, he *receives it* in the vertical, but since he is measuring in the diagonal basis, the only measurement options are / or \.

@leilanicatrose3576

Ай бұрын

⁠@@ImprobableMatter oh okay, so bob can still measure any polarised photon, but gets the reading simply based on the filter that he has used at that time. Thank you for clarifying!!

If a quantum internet is required doesn't that mean, that one would have to have one dedicated fiber optics connection between every single receiver? so for a few actors, that would be possible, but even just for every country a connection to every other country would be [assuming 200 countries and if im not wrong this should be combination statistics = 200!/(2!*(200-2)!) ] 19900 connections. this seems impractical. Or am i missing something?

@ImprobableMatter

5 ай бұрын

If you want a super-duper secure one, yes. But you could probably trust Google etc, so people would only need to connect to a few fairly local servers belonging to trusted parties. I mean, you have to trust whoever manufactured your CPU, your RAM and so on anyway.

@theonlyhero

5 ай бұрын

@@ImprobableMatter Google has currently plans for about 50 data centers worldwide. If we assume 3 other companies have the same (e.g. microsoft, Facebook and apple or so) then the number isn't lower. Or am I missing something?

@ImprobableMatter

5 ай бұрын

That's fair, but the point is that you don't need a dedicated fiber optic between every node/datacenter. They could all share a common quantum fiber network (just like they do now) and they would detect if someone was trying to eavesdrop. For long distances, satellite constellations could be used. A single polarization analyzer is also quite small, so it would be reasonably cheap to distribute many "Bobs" around the world as well.

@theonlyhero

5 ай бұрын

@@ImprobableMatter ah ok, thx!

One thing i don't understand is to how change our internet etc into photon based

@ImprobableMatter

2 ай бұрын

I had mine changed to photon based recently. We had a fiber optic connection put in.

@Pentagram666mar

2 ай бұрын

@@ImprobableMatter the answer is way easier than i imagined :P

Detecting an evesdropper feels a bit... secondary. I want to know no one can evesdrop. Not whether someone did. I want to aim to send a 100% secret message and have both parties know for sure its from each of us. But without needing to reprove identity frequently.

@monsterthenergydrink

5 ай бұрын

The point is that if you can detect an eaves dropper then you send a test message before the real one which is why the DDoS attack still works but you won't ever have the content of the message or information you want to send actually stolen, so detection is pretty much just as good as just sending the secret message

So when they got them wrong but nobody was listening, wuold they think someone was listening?

Looks like someone is a fan of cartoon shows 😄1:58

11:15

Fiber optic would not affect Because if it did the Internet we shut down

9:05 the Chinese satellite MICIUS sends entangled photons.

@car103d

Ай бұрын

Science Mag about MICIUS kzread.info/dash/bejne/ZoWgxa2uqKetotY.html

How the hell do you have 194 visualisations, 2 comments and 34k+ likes???? Edit: in all your videos you have exactly 34.060 likes?? What is going on here?

This might seem a silly idea for a video, but I was too young to understand the craze that happened surrounding the concept of Cold Fusion. Could you explain what they hell it was, and how it would have supposedly worked. I don't personally believe such a thing could exist , but trying to read into it and understand why it received so much backlash is a nightmare to unpack that I just can't make any sense of.

Just noticed you have 34.060 likes in the latest video. Is this some youtube bs?

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