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First Quantum Cryptographic Data Network

Posted by ryuzaki0 on from the networks-with-friggin-lasers dept.

jdubs writes to tell us ScienceDaily is reporting that scientists at Northwestern University and BBN Technologies have demonstrated the first truly quantum cryptographic data network. From the article: "Kumar's research team recently demonstrated a new way of encrypting data that relies on both traditional algorithms and on physical principles. This QDE method, called AlphaEta, makes use of the inherent and irreducible quantum noise in laser light to enhance the security of the system and makes eavesdropping much more difficult. Unlike most other physical encryption methods, AlphaEta maintains performance on par with traditional optical communications links and is compatible with standard fiber optical networks."

21 of 65 comments (clear)

  1. Quantum post by BadAnalogyGuy · · Score: 5, Funny

    This post is not insightful!

    1. Re:Quantum post by waxigloo · · Score: 3, Interesting

      I agree. It would have been nice if the article compared what they have done here with what is already been done by commerical quantum key ditribution (www.magiqtech.com). It is not clear from the article what is actually the new breakthrough...

    2. Re:Quantum post by Anonymous Coward · · Score: 2, Funny

      it was both blinking and not blinking. then you went and spoiled everything by observing it...

  2. Will we know? by SanityInAnarchy · · Score: 4, Interesting

    We know a working quantum computer, on a sufficient scale, can crack modern encryption in something like linear time, or at least better than the current exponential time. We know that no such computer exists now, or at least not on sufficient scale to enable the NSA to snoop all our encrypted traffic.

    Or (tinfoil hat time) do we really? Will we know when this happens, or will it be classified and snapped up by the government? Would we notice that? (The way we did with the a-bomb -- contests were held for whose work could be classified the fastest.) Or would we only notice years later, when it's finally leaked...

    --
    Don't thank God, thank a doctor!
    1. Re:Will we know? by johndoe42 · · Score: 5, Interesting

      Really? Last I heard, quantum computers were not known to be able to solve NP-hard problems in polynomial time, and, in the absence of cryptographic breakthroughs, breaking symmetric ciphers ought to be difficult NP problems. Grover's algorithm might help, but only enough to reduce the rate of exponential growth a bit (i.e. 256-bit encryption will stuff be effectively unbreakable by any technology, unless BQP >= NP).

      That being said, quantum computers can easily break RSA, ElGamal, and related schemes (using Shor's algorithm, for example). But this quantum encryption thing, absent any details, doesn't look like it's trying to do assymetric encryption.

      See http://en.wikipedia.org/wiki/Quantum_computing for more info.

    2. Re:Will we know? by SanityInAnarchy · · Score: 2, Insightful

      As far as I know, you usually need asymmetric encryption to reasonably set up temporary symmetric encryption. And so many systems today are based on RSA, which is what I'm talking about. Basically, it makes SSH no more secure than Telnet.

      --
      Don't thank God, thank a doctor!
    3. Re:Will we know? by Anonymous Coward · · Score: 5, Interesting

      The problem is one of information theory - read Cryptonomicon for a good fictional overview of these type of issues - the problem is that *if* they had a working quantum decrypter could they use it yadda yadda, well, there's two options - either they start using it left right and centre and soon everyone *knows* that the NSA can read encrypted data (in which case the bright monkeys will switch back to one-time pads and the hell that is key exchange) - or the NSA will be very clever about it and only act on that information they have decrypted that they can explain coming from other sources, such as:-
      1. crack PGP1024-bit message using quantum goodiness
      2. get juicy intelligence from message
      3. 'bust' someone in the 'organisation' who had access to this information
      4. go public with/act upon the intelligence, claiming where needed 'x told us everything'

      The whole issue is one the allies had to deal with throughout WWII since they had cracked enigma and so wanted to act on the intelligence without letting the axis know that we could read their codes.

      Having said all that though - I'm a big believer in the cock-up Vs. conspiracy theory, meaning given two situtations it is usually always the case that the conspiracy is fantasy.

    4. Re:Will we know? by strider44 · · Score: 4, Informative

      I don't mean to be a pedant but this article has nothing to do with quantum computing. It just has to do with using quantum mechanics to design a data stream that is impossible to be eavedropped on according to quantum physics. See Wikipedia for more details.

    5. Re:Will we know? by maxwell+demon · · Score: 3, Insightful

      An existing large enough quantum computer would make ssh much less secure, but as long as not everyone can afford his own quantum computer, it would still be magnitudes more secure than telnet. It's still a difference if e.g. your encrypted banking password can be read by the government, or if it can be read by anyone having access to a computer in between.

      --
      The Tao of math: The numbers you can count are not the real numbers.
    6. Re:Will we know? by kalirion · · Score: 2, Funny

      And add "any hacker who gets can break into the systems of such an organization."

    7. Re:Will we know? by ajs · · Score: 4, Informative
      As far as I know, you usually need asymmetric encryption to reasonably set up temporary symmetric encryption.

      Yes and no. Let's step back and cover what is currently done:

      Typically you generate a public/private key and give one out to the world (the "public" part, though in most systems that's an arbitrary distinction). The reason you do this is because it's "safe" to give out the public part (no one can decrypt your messages with it) and it gets around the horrible problems inherent in trying to move a key around that *can* decrypt your data (such as those used in symetric key systems). Now you could just stop there, and encrypt all of your data using the target's public key, but it turns out that that's fairly computationally expensive.

      In order to speed up the process, you can just use the public key to encrypt a random, one-time session key that you use as the input to a (much faster) symmetric key algorithm such as IDEA, blowfish, twofish, DES, 3DES, etc. Now you have a fast communication path and, as long as the symmetric key system is believed to be at least as strong as the asymetric key system, you have not lost any security.

      Now, if symetric key is so much faster, why don't we just use THAT? Well, we would, except that it's a pain to get the symetric key to the target without compromising it. You could, for example, send it via U.S. Post (slow, and not 100% reliable), send it over a private communication channel like a leased line (expensive, not secure), etc. There are other ways too. For example, you can NOT send the key, but have an out-of-band agreement as to how they are generated. For exaple, you might agree to use a pseudo-random number generator (PRNG) wiht a particular seed on a particular date, generating a new key each day. That's not too bad for some purposes, by typically it's not strong enough for truly important information, as PRNGs tend to have their own flaws, and anyone who finds out what you're doing essentially has every key you'll ever use until you exchange a new seed.

      What quantum encryption changes is this: it gives you a secure channel over which to communicate (usually at low bandwidth), so you can use it to move a key for symmetric key encryption, and then perform your encryption with that. If anyone evesdrops on the connection, you are guaranteed to know (because the data will be changed, and presumably you've built in appropriate checksums so that you will realize that you now have line noise), and you won't use that key (providing trivial denial of service, which is why this isn't good for non-physical communications).

      Quantum computing essentially replaces asymetric key encryption for short, physical links in terms of providing a secure way to exchange symmetric keys. If it gets up to the point that high volumes of data can be moved through the quantum link (which the article is not describing), then you can just move a one-time pad through the link, and your encryption algorithm will be a simple xor.
    8. Re:Will we know? by ajs318 · · Score: 2, Informative

      When an invention's time comes, the invention comes. The telephone was invented almost simultaneously by both Alexander Graham Bell and Elisha Grey, who arrived at the patent office only a few hours too late. The phonograph was invented by Thomas Alva Edison at around the same time as the gramophone was invented by Emil Berliner. The filament bulb was invented by Thomas Alva Edison only one year after it had already been invented by Joseph Swan {and unfortunately still has not been banned}. A public-key encryption algorithm was invented in the UK in the 1970s, but kept under wraps by the UK authorities; it was later discovered independently by Rivest, Shamir and Adelman in the USA. Details of the UK invention emerged shortly before the US patent expired.

      Given all of which, I think it's reasonable to suppose that when the time for quantum computing arrives, quantum computing will arrive. With even the current state of communication systems, and assuming that communications will continue improving over time, it would be damn nigh impossible to suppress the facts.

      --
      Je fume. Tu fumes. Nous fûmes!
  3. The real question is... by und0 · · Score: 2, Funny

    Has Harold a research team of his own?

  4. Cheating! by Mister+Impressive · · Score: 3, Funny

    They changed the outcome of the test by checking the results!

    --
    Let the commencement BEGINULATE!
  5. Perfect case in point by jonwil · · Score: 2, Informative

    When Chuck Yeager broke the sound barrier in the Bell Aerospace X-1 rocket plane, the results were kept classified by the airforce.

  6. Solution without a problem by suv4x4 · · Score: 2, Insightful

    Is modern digital cryptography so easily broken anyway? No.

    I don't mind research on quantum tunnels and so on regarding cryptography, but I really wonder: who ever needed it.

    BTW, anyone need a noisy stupid mechanical donkey? Oh yea the military do. I swear this is where this is going as well. No general wants someone to sniff his porn traffic.

    1. Re:Solution without a problem by chicoryn · · Score: 3, Interesting

      I can't claim to be an expert on the subject but rather then an actual new encryption quantum cryptography is an way to ensure no one can listen without you knowing(Making use of the "Can't watch without changing" law in quantum physics), while it isn't that much of an problem right the computer power will continue increasing, better to have the solution before the problem right? And yes this isn't going to be an home device anytime soon since it's WAY to expensive for home use.

  7. Can some-one please explain? by kwikrick · · Score: 5, Informative

    The article does not explain at all what quantum cryptograpy is and how it's different from the cryptograpy we all know. Ah, but here's wikipedia to the rescue http://en.wikipedia.org/wiki/Quantum_encryption:

    Quantum cryptography uses quantum mechanics for secure communications. Unlike traditional cryptography, which employs various mathematical techniques to restrict eavesdroppers from learning the contents of encrypted messages, quantum cryptography is based on the physics of information. Eavesdropping can be viewed as measurements on a physical object -- in this case the carrier of the information. Using quantum phenomena such as quantum superpositions or quantum entanglement one can design and implement a communication system which can always detect eavesdropping. This is because measurements on the quantum carrier of information disturbs it and therefore leaves traces.

    --
    assignment != equality != identity
  8. Friggin Quantum crap. by Rob+T+Firefly · · Score: 4, Funny

    I'm sick of Quantum Cryptography. Every time I try and encrypt something, this smartass time-travelling scientist guy takes over my body, kisses some girl I know, and solves one of my lifelong problems before disappearing in a flash of cartoon FX.

    --
    Slashdot Burying Stories About Slashdot Media Owned
  9. Story reads like a press release by hotspotbloc · · Score: 3, Informative
    And it seems it is. Others including UPI got caught too.


    Besides, a point-to-point quantum crypto connection was done around two years ago in Europe. Also the "article" never talks about the one thing you can't do with quantum traffic: route.

    --
    "I hate to advocate drugs, alcohol, violence or insanity but they've always worked for me" - HST
  10. Link to BBN by jesboat · · Score: 2

    BBN's page for quantum crypto