• douglas steel

    Quantum cryptography is essentially then a means of detecting interception as opposed to prevention. Kind of like a wax seal done in the 8th century. 😂

  • Nevin West

    Great episode. Super cool to learn about how defining the diagonal state leaves the the linear state undefined. Excited to see the proposal for how quantum entanglement could be networked over the entire world.

  • Thomas Busse

    Who needs to decrypt if you can just mockingbird and run like Matthew O'Dowd and regurgitate ouamouamua about asteroid mining? You Sold Out, sunshine. Not Cool. CIA-slut.

  • Todd Hubers

    There's nothing known to be wrong with symmetric encryption. It basically uses One-Time-Pad cryptography (which is mathematically proven to be unbreakable), a pseudo-random key-generator, and optionally some more complex shuffling. RSA is not used for "encryption" – it's slow and not as secure, so it's used only for private key exchange. With Post-Quantum encryption (lattice) there's no need to build new infrastructure for Quantum Encryption. Also, Quantum states are so sensitive that I'm not sure how they would be "routed" globally. I believe most implementations focus on point to point, or point to multi-point links, not an "internet". I see it as a "line" that in theory cannot be successfully "tapped", that's useful in some situations, but not global networking. Finally, I read that although theory is sound, there is an arms race in engineering of building a secure system versus exploiting the design, because implementation cannot accomplish the perfection of the theory.

  • Thomas Busse

    You don't need to build an encrypted quantum internet to build a quantum internet. You could just build quantum internet and then figure out to encrypt it later (like the internet was built), or not encrypt it at all and just throw everything open and use diplomacy, peace, and steganography and change the cultural paradigm. At a certain point, things are not going to be encryptable.

  • Jonathan Ra

    In either of the scenarios, how would Albert and Neils communicate which basis they are going to choose. Wouldn't they need to know how the other measured?

  • Tim Morton

    Is it possible to "rebuild" an objects wave function while quantum teleporting all of the respective particles to a new location where its wave function would collapse again; and if so, why isnt WonkaVision a thing yet?

  • Vasubhya Diwan

    a little off the topic question
    according to qft, a particle is a result of vibration in its respective field
    whereas according to string theory, a particle is just a result of vibrations in strings
    both of the theories are incredibly close and yet qft is considered to be true and we are not sure about string theory????

  • load 3r43

    I have a question, what would happen if two people on a spacecraft crossed the event horizon of a black hole? What would the people inside the space ship experience?

  • SpudHead

    Why not do this? Both parties create a public key, they then encrypt the public key using a random salt. Obviously the encrypted public keys are going to lead to a failed challenge/response but, since both parties have the correct private keys the challenge response data (might take a few) can be reversed to figure out what the other party's salt is. From there the correct public key can be calculated and normal RSA can then continue. It shouldn't be possible for a quantum observer to unravel that process.

  • Nafrost

    6:50 Are you sure that this is because of the Heisenberg uncertainty principle? I thought it is because in quantum mechanics only certain quantized values are allowed.

  • Nafrost

    Cool new idea for a series, but I would really want to see a series on prototypes theories of everything like quantum loop gravity and entropic gravity.
    Can you do a series on that?

  • kaczan3

    Remember when Alice and Bob were actually Adam and Bob? But women complained that it was sexist so it got changed to Alice? This is women's only "contribution" to crypotgraphy.

  • TheWyrdSmythe

    So how are these quantum communications sent long distances? Don’t repeaters have to “tamper” with the signal?

  • Rose Dunphy

    Somebody bungled the audio on this one 🙁
    Guess I'll just have to enjoy my free content very slightly less 😛

  • Gary Pearson

    Excellent summary of an important topic. Note that the work on a post-quantum encryption scheme for the internet (alluded to in many other posts) is on going, and as of yet, the jury is out as to whether or not a practical replacement will be in place before a sizable quantum computer is up and running.

    For a follow up on quantum computing and crypto, you might want to include a little bit on quantum money. For just as RSA encryption schemes may well soon fall to quantum attacks, blockchain codes will be vulnerable as well.

    As to quantum money, one can imagine the "no cloning" theorem could be used to make counterfeit proof currency. See stuff on Stephen Wiesner for the original version, or maybe Scott Aaronson's work for more recent versions.

    By the way, how do you find time to read +1000 comments? Armies of minions or gallons of coffee (or perhaps, armies of minions armed with gallons of coffee?)

  • bizo237

    Quantum internet not happening. Unless they use repeaters in the loop, with classical heuristics. They could try and supplement remote neural monitoring over the cell network, so the information is still monitored.
    As it stands information is being force fed yet again. Net neutrality is being reversed.
    You maybe considered a "empowered individual" for just watching this video. Which them means you can be tortured in your home, in your bed with "nonlethal" directed energy.
    Measuring and reporting the illegal biological frequencies to the FCC results in nothing.
    People are being killed, because of the fear of sadist codependent parasitic morons.
    Privacy is now a privilege.The status quo treats individual's psychologically healthy need as something to be afraid of, under the false pretenses of security.

  • Atharva #breakthrough

    wait but why is factoring large numbers so hard. isnt the algorithm polynomial? u check sqrt n numbers if they divide n and youve found both factors of that number?

  • Wade Wilson

    You cannot transmit entangled particles over the internet. You are just as likely to send pancakes over the internet. Not possible!

  • Kevin Roth

    Bruh ive been watching your vids for years nonstop, and ive never asked this, HOW DO YOU KNOW SO MUCH…..

  • Astrion

    Heisenberg: You cannot defeat me.

    Einstein: I know. But they can.
    Quantum entangled particles burst out of the Palace of Asgard

  • Adam Schork!

    Best explanation of cryptography I’ve heard so far. The mathematical visuals helped. Always love these videos. 🙂

  • Daryl Supercalifragilisticexpialidocious

    Thank God he did not mention Calvin in this video . Is Calvin his boyfriend or something ?

  • Phillip filkins

    Do you ever get high as +×@# and watch PBS Space Time and think… Holy $#!+ God and the Devil are talking to me

  • Keith Cancel

    There already is are cryptography algorithms that run for a traditional computer that are post0quantum secure. It's just widely used public key crypto is easy to break with a quantum computer. Although there are some algorithms based on hashing that are still secure even in the face of a quantum computer, and a few other techniques.

  • Klaus Bolvig

    Over 100 year and still going strong. Way of going dear Albert. But naturally he will be tested an tested for the future as well. I guess a Nobel price for the physics to disprove a fraction of his theory is wrong is guaranteed. In % not much can be left to disprove, but that fraction could have a snowball effect. Just a theory though

  • cyrus05w

    I have not yet checked the date on this video but you guys may want to talk to PlayStation you guys may have your information a little behind.

  • cyrus05w

    I have not yet checked the date on this video but you guys may want to talk to PlayStation you guys may have your information a little behind.

  • Lucifer Beezelbub Mephistophilies

    Are we at that point now yay!!! I've been waiting for them to get to this point. The first binary coding of the quantum software age

  • Nicolás Berrogorry

    I don't give a duck about my browsing history. I know what I am. I know the weird porn I've faped to, and I've learnt a lot through it. Most of my history is science videos and programming manuals.

  • David Noonan

    The answer to this problem is already invented, "blockchain." The beauty of cryptocurrency is that it solves the biggest problem in computer science and decentralizes the whole process and there's no need for intermediaries, just trust between the people on the network.

  • Steve

    I watch all of your videos, but this one in particular has made me more confused and not knowing whats going on more than any of your other videos. I'm no physicist but usually your videos are some-what easy-ish to follow even with my own ignorance of the subject matter. Not this one.

  • Climate Change Fan Club

    Classical computers process streams of data in a linear fashion. data is fetched, processed, then output. Quantum computers do not do this!!! in a quantum computer your program is defined as an energy landscape which is first configured and then allowed to settle into it's lowest energy state and you read off that result. you have to perform this action many thousands of times on the same energy landscape each time capturing the result. you then sort of average all the results to get the solution to the problem defined by that energy landscape. It's a different kind of computing which isn't well suited to realtime and linear applications. quantum internet? not in anyone here's lifetime. at best you're going to see classical computers used to program quantum computers ATTACHED to the internet. things like remote access to DWAVE quantum computers for academia, for example. and no, IT WON'T RUN CRYSIS lol. current quantum computers can only process the energy landscape about 10,000 times per second and you need a classical computer to talk to the damn thing to program it and read the results.. your classical computer isn't going away anywhere for a very very long time. oh and your quantum computer has to be cooled to just a few kelvin to even begin to work otherwise the noise from the matter that surrounds it will corrupt the whole energy landscape. i think the going rate for a DWAVE quantum computer is about 30 million bucks.

  • Javier

    Guys you are absolutely awesome and your videos are always one of the highlights of my week. Please sign up on Basic Attention Token Platform so some of us can support you with BAT Tokens by using the Brave Browser! Patreon is ok, but they charge you fees that are unnecessary, since they are not doing anything really, you do all the work, you should get 100% of the cut!


    the future looks bright for the people who will have total control over the sheep's

  • Francesco Rizzo

    faster than quantum computers –> https://phys.org/news/2019-03-artificial-intelligence.html?fbclid=IwAR2238VlLQ8sAH9-uXLpwXAYNGD3bzZZxt2M9U-OAUZkiYjAmJIUDFSxgw4

  • Daniel Yount

    Excellent topic of quantum encryption(One of my favorites). With IBM and Google and even Canadian company D-wave, the Quantum computer for everyday use use is quickly becoming a reality. Knowing how to protect its data and what to watch out for and when to completely discontinue classical encryption methods.

  • paramountx

    Lol I've seen Matt a few times in NYC. First time he gave me that look that was like "yeah, I am that person" when I was glancing. The second time he was in a rush and I don't think he had time to talk.

    Either way; my hero

  • Peter Alton Mertz

    Note * Probability and Uncertainty do not equal Superposition. 

    On the issue of Superposition, the burden of proof is on the Copenhagenists. It is an absurd idea that a particle has no properties or variables until detected, extraordinary claims require extraordinary proof. Now if at any point, a variable can be predicted; that theory is invalidated; period. However, in the case of Photon Polarization, this extends into the somewhere over the rainbow category.

    What about Bell’s Inequalities and the Bell Tests that “Prove” Superposition? Well, first off John Stewart Bell didn’t even believe in the Copenhagen Interpretation, he preferred the Pilot Wave Theory until his untimely death. So obviously the person that the tests are named after, didn’t even think that his Inequalities proved superposition. All that John Stewart Bell intended to prove, is that a little round ball with a fixed location, size, properties, and variables (local realism) cannot produce the coronations of “Entangled” atomic spins. 

    That isn’t the problem because no one at the time, nor since believed that and the paper was largely ignored by the scientific community. What happened? Well, a New Age Religious group read his paper and conducted the first Bell Test using Photon’s Polarization and their correlations then went on to extrapolate that therefore Photon’s Polarization must be in superposition, in other words, it doesn’t have a polarization before it is detected. That caught on with the popular media, then other Religious Groups started pushing the idea and people presented that as a fact that Superposition had been proven when the person that created the Theorem didn’t even believe that, but he was dead at the time and couldn’t refute that assumption. 

    At that point a Zeitgeist was created, everything in the popular media, religious groups and even some physics professors started simply stating it as a fact. Because the field of photon research is so specialized, most Physics PH.Ds have limited knowledge of the subject and avoid challenging results in areas that they are not familiar with. A whole generation of future physics professors was raised in a sensationalist environment and over time, those professors started ignoring the contradictory evidence and a psychological phenomenon was created called confirmation bias infected the Science Community. 

    So let us get back to the original question “Is a photon’s polarization in Superposition”? That means that if any devices produce photons, then no one can ever predict what any photon’s polarization would ever be. Does that happen, yes all of the time, in fact, the entire movie industry is based on photons having a predictable polarization? I am not going to bring that up, I will use the slam dunk, somewhere over the rainbow example of a photon’s polarization being predicted. 

    I found this very interesting. The change of the polarization of light beam can be measured down to 100 Billionths of a tick on a watch face. Now in other experiments, physicists use polarization to prove superposition. Think about that?

    This is from the article, “Tiny magnetic tremors unlock exotic superconductivity.” Published by Phy Org…


    "The researchers employed a highly customized apparatus to search for signs of the broken symmetry. Light should rotate when reflected from samples that have this property. For Ni-Bi, the expected amount of light rotation is tens of nanoradians, which is about 100 billionths of a tick on a watch face. Jing Xia, a co-author of the paper and a professor at UCI, has one of the only devices in the world capable of measuring such an imperceptible light rotation.

    In order to measure this rotation for Ni-Bi, light waves are first injected into one end of a single special-purpose optical fiber. The two waves travel through the fiber, as if on independent paths. They hit the sample and then retrace their paths. Upon return, the waves are combined and form a pattern. Rotations of the light waves—from, say, symmetry breaking—will show up in the analyzed pattern as small translations. Xia and his colleagues at UCI measured around 100 nanoradians of rotation, confirming the broken symmetry. Importantly, the effect appeared just as the Ni-Bi sample became a superconductor, suggesting that the broken time symmetry and the appearance of superconductivity are strongly linked."


    Now here is an alternate explanation, that doesn't require "Spooky Action". The photons are not either vertically or horizontally polarized, there are within 45 degrees of either and half will pass through, however, some of the polarized photons polarization will change and some will even become circularly polarized. So as they leave the first lens, their polarization will change. Then the amount of light that gets through will change as one moves the polarized lenses to different distances. Oh wait, that is exactly what happens.

    So why is this so important? Why is a photon traveling at the speed of light changing its variables? Two possibilities that I can think of; Quantum Lensing (the Atoms are bending spacetime) or there is a force that we do not know exerting pressure on the photons.

    So what is the problem? Its the Math, we have just taken the mathematics of QED and adjusted them, it is a little complex, to say the least. Let us just say… well… um… we have a full-on Catastrophe.

    The thing to do is to keep the math that works most of the time and admit we have a Catastrophe.

  • That guy named morgoth

    why does quantum computing require a quantum internet, we have quantum computing yet we don't have a quantum internet.

  • pgibsonorg

    When you were caught browsing adult websites at work but they are now in a superposition and you are both fired and not fired.

  • Spike's Tips

    Google’s Quantum Artificial Intelligence Lab reversed time of electrons

    this would beat quantum entanglement if you can untangle/reversed time of particles and or predict the position

    Quantum device that can predict alternative futures created by scientists

    bitcoin would be no more so someone would have to come up with a new way

  • Richard Alleman

    Doesn't this man-in-the-middle test rely on only photons being used. Once the photos undergo a conversion to an electric signal (e.g. during boosting or re-distribution), the photon polarity needs to be recreated. This means that the man-in-the-middle can test the bits during the electric component of the transaction without interrupting the resulting polarisation at the destination.

  • Vishal Mishra

    Quantum crypto is important. The content of this YouTube video is reaching you over a secure (HTTPS) channel. You can use your browser to view (or download) Google's root certificate and extract it's 2048 bit RSA public key. It has 2 prime factors – each is 1024 bit in size and they start and end with bit-1. If either one is known, you can divide and compute the other factor. RSA private key file can be generated from RSA public key (or the certificate) using either one (or both) of the prime factors and some very simple tools. This breaks Internet security since you can now sign SSL/TLS certificates for any domain and they will be trusted by all browsers across the Internet. Where is the catch ? You have to be unusually lucky to generate a random 1024 bit prime number that evenly divides any RSA 2048 bit public key on the Internet. But quantum computers change the game and Shor's algorithm running on 4000 qu-bit quantum computer can factor any 2048 bit semi-prime number relatively quickly. This can wreck havoc to Internet security and quantum mechanics can suddenly affect our day to day life in such a profound way. Thanks for making such wonderful videos and spreading knowledge so that we can learn and understand the rapidly evolving technology landscape and risks impacting our own lives and those of billions of people across the world / Internet. Quantum cryptography and new security algorithms are indeed important.

  • Richard Deese

    I'm interested in how this helps with astrophysics (if it does.) So far, no one's made that clear. There are plenty of sources on the internet for information on quantum computing. Why does this channel need to be yet another one? If you can (and do) explain how quantum computing will help us understand the universe, then you'll have my attention. 𝓡𝓲𝓴𝓴𝓲 𝓣𝓲𝓴𝓴𝓲.

  • Charlie Wood

    "At this point do we just give up trying to disprove the old man and just settle for the fact that it's probably all right?" Answer: NEVER!!

    I love this channel. Never stop never stopping, scientific inquiry! I am PASSIONATE about inquisition. I barely understand anything on this channel but I understand that and give a hearty Here Here!

  • permissionBRICK

    Ah, BB84. Its a fun concept, but Diffie Hellman does exactly the same thing without Quantum equipment. You can exchange a key over a public channel without a chance of eavesdropping. The problem is authentication, how to detect a MITM Attack. And BB84 is still vulnerable to that as you said, however the "classical authentication methods" you mentioned are in fact RSA, which you explained earlier in the vid becomes useless once we have quantum computers with sufficient bits. So yeah, we are still fucked.

  • nhzxboi

    The thing that I like about this channel is it's subject matter. The thing I disdain about this channel is the "apparent" arrogance. There is no measure of inquisitiveness. Know-it-all and it's associated arrogance is discouraging. Let me tell you, cuz I know you don't know kinda thing. Arrogance, yea. I love info, I don't love being made a fool of.

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