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posted by Cactus on Tuesday February 18 2014, @03:00PM   Printer-friendly [Skip to comment(s)]
from the Making-the-NSA-cry dept.

aliks writes:

"The practical applications of quantum encryption may be getting closer. A paper published in Physical Review Letters by Vedran Dunjko, Petros Wallden, and Erika Andersson presents a way to use Quantum Digital Signatures without requiring long term quantum memory.

Phys.org provides a summary:
Quantum digital signatures (QDSs) allow the sending of messages from one sender to multiple recipients, with the guarantee that messages cannot be forged or tampered with. Additionally, messages cannot be repudiated; if one recipient accepts a message, she is guaranteed that others will accept the same message as well. While messaging with these types of security guarantees are routinely performed in the modern digital world, current technologies only offer security under computational assumptions. QDSs, on the other hand, offer security guaranteed by quantum mechanics. All of the variants of QDSs proposed thus far require long-term, high quality quantum memory, making them unfeasible in the foreseeable future. Here, we present a QDS scheme where no quantum memory is required, which also needs just linear optics. This makes QDSs feasible with current technology."

[Ed. Note] The Physical Review Letters link has all the fun details, but Phys.org provides a more understandable article for the layperson.

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  • (Score: 5, Insightful) by Techwolf on Tuesday February 18 2014, @03:03PM

    by Techwolf (87) on Tuesday February 18 2014, @03:03PM (#1633)

    I could not help but notice just how much better the editing on these articials compare to /.
    Keep up the good job. :-)

    • (Score: 4, Insightful) by Nerdfest on Tuesday February 18 2014, @03:45PM

      by Nerdfest (80) on Tuesday February 18 2014, @03:45PM (#1659)

      ... and you know you've come to the right place when a "more understandable article for the layperson" comes from Phys.org.

    • (Score: 5, Informative) by mattie_p on Tuesday February 18 2014, @04:46PM

      by mattie_p (13) on Tuesday February 18 2014, @04:46PM (#1695) Journal

      Thanks, Techwolf. We're implementing a system where two editors need to sign off on an article before it gets published. So while Cactus did the first pass, I caught a few things that he missed. I'm glad I was able to do so, because some of the stories I published without having a second set of eyes on had glaring errors. Those errors were pointed out to me in the comments or on IRC, and I was able to fix them. However, better to minimize the errors in the first place than to have a 100% fix rate. Thanks for reading.

      Also, go Physics! ~mattie_p

      • (Score: 1) by aliks on Tuesday February 18 2014, @10:58PM

        by aliks (357) on Tuesday February 18 2014, @10:58PM (#2002)

        Actually this was my first submission ever, so I was extra careful to make it good, nice to see I hit the mark.

        Thx for the edit - I'll remember that point next time.

        --
        To err is human, to comment divine
    • (Score: 2, Funny) by VLM on Tuesday February 18 2014, @05:14PM

      by VLM (445) Subscriber Badge on Tuesday February 18 2014, @05:14PM (#1715)

      "articials"

      Also, the calm mints, or if you prefer CamelCase, the CalmMints

    • (Score: 1) by sar on Tuesday February 18 2014, @05:30PM

      by sar (507) on Tuesday February 18 2014, @05:30PM (#1728)

      I second that. There was some article I saw on "the other site" where I got incorrect understanding from summary and TFA cleared it up.
      SoylentNews summary of same thing really "summed up" important info and made pretty clear what is it all about.

      Question is, who will RTFA now ;)
      Excellent work.

  • (Score: 5, Funny) by FacialPaper on Tuesday February 18 2014, @03:46PM

    by FacialPaper (284) on Tuesday February 18 2014, @03:46PM (#1660)

    [Ed. Note] The Physical Review Letters link has all the fun details, but Phys.org provides a more understandable article for the layperson.

    Holy crap, the summary not only links to actual, relevant sources, it also tells me what kinds of audiences they are aimed at. Truly we've come a long way since the days of ... whatever that other news thingy was called. That greenish one. You know the one I mean.

  • (Score: 2, Interesting) by Anonymous Coward on Tuesday February 18 2014, @04:06PM

    by Anonymous Coward on Tuesday February 18 2014, @04:06PM (#1672)

    (I agree, the quality of editing is MUCH better than that other site! Keep up the great work!)

    I'm not convinced that quantum entanglement is such a "guarantee" of security as so many stories (like this) make it out to be.
    I'm not a physicist, but it's my understanding there are no guarantees in the quantum world, only probabilities. That is,
    the premise this story assumes is that because we cannot interfere with a quantum particle without altering its state, we will
    therefore know if it's been interfered with. However is that really true? The Uncertainty Principle (from what I understand) states
    there will be some diminished level of certainty about attribute A of a particle the more you know about a related attribute B
    of the particle. However this is a scale of certainties whose precision changes, it's not either 0% or 100%, is it? Note there is a
    world of difference between "negligable probability" and "guarantee" -- is this just poor wording on all these stories' parts?
    Besides, doesn't the supposed "security" of quantum entanglement in cryptography assume we only interfere once? That is, even if the Uncertainty Principle GUARANTEED with 100.0% probability that you flip the state of a particle when you look at it, couldn't you keep poking it until it either returned
    to its previous state, or reached a high probability of having returned to its previous state? Folks could play the numbers game
    and interfere with the quantum until they're more likely than not to have returned it to its previous state. I'd imagine empirical
    data would give you the likely sequence of events needed to return quanta back to its previous state*.

    * at least for any given single attribute, or perhaps subset of total attributes, since security systems will likely only
    look at a subset of a particle's total attributes to determine whether it's been messed with.

    On an entirely different point, from the phys.org article:
    "In the distribution stage, the quantum signatures are converted to classical information through quantum measurements, but they still retain the same level of security guaranteed by quantum mechanics."

    I see this conversion process to be a major point of attack. A MITM during this conversion would defeat any security inherent
    in the quantum component (i.e., the "distribution" phase).

    • (Score: 3, Informative) by maxwell demon on Wednesday February 19 2014, @12:08AM

      by maxwell demon (1608) on Wednesday February 19 2014, @12:08AM (#2041) Journal

      The quantum guarantees are based on the fact that you cannot measure an unknown quantum state without disturbing it. That is, if somebody would try to eavesdrop your quantum messages, you'd notice it. Given that the quantum communication is always just used to generate one-time pads, being able to detect eavesdropping means that you can avoid using OTPs which are known to the attacker.

      Having said that, the security of course also depends on the attacker not being able to learn about your code any other way nor getting control of the output of your device (for example, there have been attacks on quantum encryption devices where an extra laser was used to find out the orientation of polarizators, or to blind the detectors with strong lasers and make them output whatever the attacker wanted.

      As always, any scheme is only as secure as the weakest link. And that weakest link may well be the hardware which runs the quantum protocol.

      --
      The Tao of math: The numbers you can count are not the real numbers.
  • (Score: 3, Interesting) by VLM on Tuesday February 18 2014, @05:23PM

    by VLM (445) Subscriber Badge on Tuesday February 18 2014, @05:23PM (#1721)

    There is some name game stuff going on in that the core of the design is rather than storing quantum data directly which is a tough task today, you measure quantum data and stick those measurements in plain old conventional memory till you need them. This is a gross generalization and summary, there's a reason the article is longer than one line...

    The name game is you'll still have a box on the flow chart or whatever labeled "quantum memory" its just implemented as "measure and store" rather than directly handling qubits. Maybe you could make a bad analogy to virtual memory handlers.

    If you want a stereotypical cruddy soylent-is-automobile-analogy, it would be something like if you can't store spare bodywork panels at the shop because they're a bit unwieldy, just store 3-d models of body panels and print them when necessary. Won't be quite as fast and accurate as picking one up off the shelf, but it'll do well enough.

  • (Score: 2, Interesting) by Pav on Tuesday February 18 2014, @05:29PM

    by Pav (114) on Tuesday February 18 2014, @05:29PM (#1726)

    ...if stock crypto was actually usable our NSA problem would be less pressing. :-/ I'm having my own crypto issues [debian.org] (plugging my own bug report) right now, and I'm certainly not holding my breath for this quantum stuff, but I wonder how it'll be obfuscated and weakened if/when it does finally filter down to us?

  • (Score: 3, Informative) by VLM on Tuesday February 18 2014, @05:29PM

    by VLM (445) Subscriber Badge on Tuesday February 18 2014, @05:29PM (#1727)

    Also the arxiv entry for the PRL paper seen here (not a rickroll, promise)

    http://arxiv.org/abs/1309.1375 [arxiv.org]

    links to this supplementary at

    http://arxiv.org/abs/1311.5760 [arxiv.org]

    "Part of the security analysis is similar to the one in our earlier paper arXiv:1309.1375, since it uses similar methods applied to a different setting. It is included here in detail, in the supplementary material, for completeness"

    I have not studied either in detail but they look interesting.

  • (Score: 3, Interesting) by TrumpetPower! on Tuesday February 18 2014, @05:56PM

    by TrumpetPower! (590) <ben@trumpetpower.com> on Tuesday February 18 2014, @05:56PM (#1762) Homepage

    I think we're most of us here familiar with Munroe's $5 wrench. Good cryptography is an important part of the challenge of secure communications...but it's turned out to be the easy part that's already mostly solved. It's been a long time since successful attacks relied on cryptological weaknesses; today, it's all about avoiding the cryptography entirely. Exploit a programming bug in the target computer to take control; gain physical access to the machine and have your way with it; or use some sort of social engineering attack to get people to just willingly hand you the keys.

    What I'd like to see is some sort of innovation that protects us even from ourselves -- if that's even possible.

    I'd also like to see the enemies of liberty who're running rampant in the "secret" branches of our governments tossed in prison and left to rot. It's bad enough that we have criminals trying to take advantage of us, but paying taxes for the privilege of being taken advantage of by the most concerted attack on freedom adds so many layers of insult on top of profound injury it's not even funny.

    So, yay for quantum cryptography...but maybe somebody will be inspired to address the more pressing (and, granted, difficult) half of the problem?

    Cheers,

    b&

    --
    All but God can prove this sentence true.
    • (Score: 2, Interesting) by Cactus on Tuesday February 18 2014, @07:48PM

      by Cactus (32) on Tuesday February 18 2014, @07:48PM (#1844) Journal

      "What I'd like to see is some sort of innovation that protects us even from ourselves"

      Isn't this what consumer electronics / software companies try and do? Rather, isn't that their excuse for locking down computers and devices as much as possible? "Smartphone" OSs that are basically just buttons to launch programs, locked down boot loaders, scarey warnings from Windows' UAC and web browsers when you venture off the beaten path, etc, etc.

  • (Score: 4, Funny) by Covalent on Tuesday February 18 2014, @07:22PM

    by Covalent (43) on Tuesday February 18 2014, @07:22PM (#1822) Journal

    The Phys. Rev. Lett. page starts with a big banner:

    ---View this article on our new beta website "TRY IT"---

    Needless to say I did NOT view it on Beta. Just on principle.

    --
    You can't rationally argue somebody out of a position they didn't rationally get into.