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Scientists Release Working Prototype Of CAPTCHA-Based Password Assistant 86

Posted by timothy
from the holding-out-for-retinal-scans dept.
An anonymous reader writes "Last year Slashdot ran a story on scientists from the Max-Planck-Institute for Physics of Complex Systems in Dresden, Germany developing a novel method to improve password security. A strong long password is split in two parts; the first part is memorized by a human, and the second part is stored as a CAPTCHA-like image of a chaotic lattice system. Today, after a year of work, the same group at Max Planck Institute released a working prototype online, where everybody can try this technology to encrypt files (Java plugin required)."
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Scientists Release Working Prototype Of CAPTCHA-Based Password Assistant

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  • by msheekhah (903443)
    Not sure this is any better. If someone can guess the password, they can read the captcha. That is, unless the captcha is somehow stored on the local machine, which makes the file inaccessible except from that terminal.
    • Re: (Score:3, Informative)

      by Anonymous Coward

      Actually, this is better -- it prevents brute-force attacks unless you have a very, very good method of solving CAPTCHAs. Even if you can solve the CAPTCHA, though... there's no guarantee that you'll get a good CAPTCHA based on the password you're trying.

      • Re:um (Score:4, Insightful)

        by dgatwood (11270) on Saturday April 07, 2012 @09:17PM (#39609917) Journal

        Of course, it's a security scheme designed using Java just two days after a story about a security hole in Java that allowed automatic installation of a trojan [slashdot.org]. Thanks, but no thanks. You can keep your security if that's the language you want to use to implement it.

        • Re:um (Score:4, Interesting)

          by errandum (2014454) on Saturday April 07, 2012 @09:52PM (#39610049)

          Because they are, clearly, associated.

          Most encryption algorithms and libraries in java follow the standards implementation. If used properly they are as secure as possible.

          Don't confuse the relative security of a language (in allowing you to run code outside of the VM) with encryption algorithms. That's completely idiotic. It's like saying you should not eat meat because it's raining (yep, as idiotic as that).

          • I don't think dgatwood is commenting on encryption, just the delivery system for this attempt at security.

            If you already have Java installed and/or active on your system then this CAPTCHA approach doesn't make your system any more vulnerable then it already was (assuming a properly signed certificate accompanies the code).
            • by errandum (2014454)

              No, he said the attempts at encryption should not be made using java because a story showed that you could run code on a computer via an applet.

              It's ridiculous. Or even worse than that, it's someone so ignorant it hurts, but that feels entitled to do statements like that. I should have used my modpoints instead of commenting, since people might take him seriously and he needs to get downvoted and hidden fast.

              His comment is akin to saying that since C and C++ has been used on viruses that get delivered as wi

              • by dgatwood (11270)

                No, I'm saying that nobody in their right minds should have Java even enabled on their computer because it fundamentally breaks the whole security model of the web browsing environment. Therefore, even as a prototype, it is unacceptable.

                I would much rather have seen this implemented in JavaScript using the new HTML5 file API [mozilla.org]. It can provide the required access to local files without requiring testers to significantly increase the potential attack surface of their browsers.

                His comment is akin to saying tha

        • Re:um (Score:5, Funny)

          by theshowmecanuck (703852) on Saturday April 07, 2012 @11:40PM (#39610437) Journal
          I heard a story about a virus written in C. That's why I'm writing this on Slashdot with an abacus.
      • Re:um (Score:4, Interesting)

        by Patch86 (1465427) on Sunday April 08, 2012 @06:06AM (#39611421)

        Why bother having the user set the word that is going to be displayed as a CAPTCHA? Why not just have the user set a password in the conventional way, and then show them a random CAPTCHA (also in the conventional way)? You'd get the same defence against a computerized brute-force or dictionary attack, but without the added security weakness of the user giving away the second part of the password (such as by key logger, or nosy desk neighbour, or writing it on a post-it).

        I suspect the reason most systems don't ask for a CAPTCHA alongside password entry is because CAPTCHA is a pain in the rear for users- which the system in TFA would still be.

        • Why bother having the user set the word that is going to be displayed as a CAPTCHA?

          They don't.

    • It's to prevent brute force attacks (from the old article):

      The second component is transformed into a CAPTCHA image and then protected using evolution of a two-dimensional dynamical system close to a phase transition, in such a way that standard brute-force attacks become ineffective. We expect our approach to have wide applications for authentication and encryption technologies.

      From some quick testing the CAPTCHAs are reused so I'm not all too sure it does this successfully, but it's an interesting idea nevertheless.

      • The CAPTCHAs may be reused but the background patterns change based on the password input. Even if the CAPTCHA is broken, it may slow brute force attempts due to the additional processing required to decode the CAPTCHA.

        • Re:um (Score:4, Interesting)

          by Patch86 (1465427) on Sunday April 08, 2012 @06:11AM (#39611437)

          So in what way is this an improvement over a regular CAPTCHA (with a random set of letters and numbers, not set by the user)? A conventional random CAPTCHA will defend against brute force attacks in exactly the same way.

          TFA's proposed method would mean that either a) users will manage to remember the second part of their password (in which case why display it on screen- why not treat it like a regular password and keep it in the user's head) or b) users will need to read the CAPTCHA and enter the word as they see it (in which case why keep the word the same each time, why not randomise it like normal).

          • Entering any password, right or wrong, will generate an image. That image has to be parsed by the CAPTCHA, taking up considerably more cycles than running through the next possible password. On top of that, there's a chance of a false negative--thinking that there's no valid CAPTCHA when there is one, which breaks the entire run.

  • Rather than attempting to personally evaluate the paper, not being an expert in this area, it'd be interesting if a third party has done some analysis, even preliminarily, on the system, so we can rely on more than the authors' own views. The paper itself was published in a somewhat strange venue for a new cryptosystem, Europhysics Letters, which isn't really a problem, but doesn't provide strong assurance that cryptography experts have vetted it, either (but perhaps they have elsewhere?).

    • Re: (Score:1, Informative)

      by Anonymous Coward

      Rather than attempting to personally evaluate the paper, not being an expert in this area, it'd be interesting if a third party has done some analysis, even preliminarily, on the system, so we can rely on more than the authors' own views. The paper itself was published in a somewhat strange venue for a new cryptosystem, Europhysics Letters, which isn't really a problem, but doesn't provide strong assurance that cryptography experts have vetted it, either (but perhaps they have elsewhere?).

      Delirium - this is exactly why we post in on Slashdot - to get it evaluated :-) If you want to get it done - do it youself (did you see the Fifth Element movie ? :-)

      Konstantin

  • by Plouf (957367) on Saturday April 07, 2012 @08:09PM (#39609653)
    This requires self-signed applet with full privileges so by using this new security solution I will put my computer at risk. Isn't that great? I would have expected that people working in the security domain would not have the "I don't bother about actual rights I need so let us request full access" attitude.
    • by Anonymous Coward on Saturday April 07, 2012 @08:16PM (#39609677)

      Plouf - we need these permissions in order to read the files :-)

      As far as self-signed goes - we did not want to spend $500 on a chunk of bytes :-) Please trust us :-))

      Konstantin

      • Re: (Score:2, Funny)

        by Anonymous Coward

        A security researcher asking people to blindly trust strangers........

        • Re: (Score:2, Interesting)

          by Anonymous Coward

          A security researcher asking people to blindly trust strangers........

          IMO they really aren't. As it is uploaded unobfusacated and anyone can download it. It then takes 2 seconds to drop it in to the one of many java decompilers and you can read it yourself.

          Who can blame them for not spending a couple of hundred dollars on a sining cert? I can't for a proof of concept.

          • A security researcher asking people to blindly trust strangers........

            IMO they really aren't. As it is uploaded unobfusacated and anyone can download it. It then takes 2 seconds to drop it in to the one of many java decompilers and you can read it yourself.

            Who can blame them for not spending a couple of hundred dollars on a sining cert? I can't for a proof of concept.

            If end users are expected to decompile the code and inspect it every time it downloads (or updates) then this isn't a solution for the +99% of internet users who don't know Java. As for me, I'd rather spend the little extra time typing in a second password without this CAPTCHA scheme and not decompiling & inspecting code.

            • by krrose27 (2612933)

              A security researcher asking people to blindly trust strangers........

              IMO they really aren't. As it is uploaded unobfusacated and anyone can download it. It then takes 2 seconds to drop it in to the one of many java decompilers and you can read it yourself.

              Who can blame them for not spending a couple of hundred dollars on a sining cert? I can't for a proof of concept.

              If end users are expected to decompile the code and inspect it every time it downloads (or updates) then this isn't a solution for the +99% of internet users who don't know Java. As for me, I'd rather spend the little extra time typing in a second password without this CAPTCHA scheme and not decompiling & inspecting code.

              My point is that this is a proof of concept. For some reason people are irrationally flipping out (imo). When the fact is they could have distributed it in a desktop launchable (just the jar) form (requiring more user work(executing a command and or more complicated.. java != your friend) and people would never see any code signing issue. The fact is that to make it easier you get a warning since they don't want to shell out hundreds for a proof of concept. Can you blame them? My statement was more of a

      • by Anonymous Coward

        we need these permissions in order to read the files :-)

        There are several mechanisms to upload files over HTTP without requiring local execution privileges. Why use this unnecessarily intrusive method?

        Please trust us :-))

        You're a security researcher?

      • by netsharc (195805)

        Overuse of smileys detected... God damnit, wie alt seid ihr, 16?

      • by FrootLoops (1817694) on Sunday April 08, 2012 @04:35AM (#39611205)

        There are too many oddities for me to try out the service, sorry.

        1. The service isn't hosted on a .edu domain.
        2. The about page [www.crpt.me] makes a remarkably strong and vague claim for a group of scientists: "We are currently the strongest online encryption service available on the Internet."
        3. The story was submitted anonymously rather than with a "full disclosure" warning.
        4. There's no link on the web site to any supporting institutions, grants, or anything like that, even though the summary twice mentions the Max Planck Institute.
        5. The unsigned software wants full access to my machine.

        For all I know, this is an elaborate ruse to get a few poor saps to run untrusted code. I have nothing but the web site's word and the word of an anonymous commenter to go on balanced against the above weirdness, so I'm going to play it safe and move on.

        As for you, "Konstantin," perhaps you're just a weird person, but there are way too many oddities for me to simply believe that you're the K. Kladko from the paper.

        1. Your grammar and style are remarkably informal for an academic. You write like a teenager.
        2. You use way too many smilies for a security researcher.
        3. You sign your name while posting anonymously--just sign up for an account already.
        4. You expect me to run untrusted code on my machine as a security researcher just because you say, "Please trust us". Seriously? Seriously? (It bears repeating.)
        5. You're making lots of comments here. Usually scientists don't make any appearance on /. comments about their work, or if they do their posts are highly informative (eg. The Bad Astronomer).

        My strong suspicion is that you're just rather young and naive and don't have enough supervision on this project. I'm not trying the software though.

        • The service isn't hosted on a .edu domain.

          As I understand it, only institutions in the United States qualify for a .edu domain. A British institution would be .ac.uk, etc.

          The unsigned software wants full access to my machine.

          Can you figure out how to express, in Java, a capability that applies only to those files chosen with a file chooser? And can you figure out how to make code signing certificates as affordable as SSL certificates? Do individuals (as opposed to corporations or LLCs) even qualify for such certificates?

          • As I understand it, only institutions in the United States qualify for a .edu domain. A British institution would be .ac.uk, etc.

            Thank you, I meant to say ".edu or similar domain" but didn't write it.

            Can you figure out how to express, in Java, a capability that applies only to those files chosen with a file chooser? And can you figure out how to make code signing certificates as affordable as SSL certificates? Do individuals (as opposed to corporations or LLCs) even qualify for such certificates?

            Good questions, and I do not know the answers, but none of the possibilities will get me to run the software. I would prefer a server-side setup like web mail attachments use for a test run over the current setup, so I can encrypt data I don't care about without giving access to my machine, just to try the service out. In the current incarnation they may as well have given us a download link and said, "here run this!"

          • by mrmeval (662166)

            We have scam 'institutions' that are there to sucker people with the IQ of a douche into getting government grants and loans for "technical training in computers". There are several of them that have a .edu domain.

            • We have scam 'institutions' that are there to sucker people with the IQ of a douche into getting government grants and loans for "technical training in computers". There are several of them that have a .edu domain.

              Advertisement for TrustUs.edu
              Do you want to protect yourself against scam education institutions but don't think you have the proper training? Don't doubt yourself, just trust us.

              At TrustUs.edu you'll learn how to spot questionable, suspicious or illegitimate education institutions. We provide you first hand experience, and even offer extra credit courses for those that need additional attention.

              When it comes to knowing who to trust, you just need to trust us. At TrustUs.edu, we offer life lessons

        • by hankwang (413283)

          There's no link on the web site to any supporting institutions, grants, or anything like that, even though the summary twice mentions the Max Planck Institute.

          whois crpt.me results in:

          Registrant Name:Sergej Flach
          Registrant Address:Noethnitzer Str. 28
          Registrant City:Dresden
          Registrant State/Province:Saxony
          Registrant Country/Economy:DE
          Registrant Postal Code:01187
          Registrant Phone:+65.03267603

          At least, it is one of the authors and the address matches the Max Planck institute. I'm not sure whether a .me (Monten

        • by ignavus (213578)

          My strong suspicion is that you're just rather young and naive and don't have enough supervision on this project.

          That's a no-brainer on /.

    • by SashaMan (263632) on Saturday April 07, 2012 @09:31PM (#39609969)

      Absolutely - I couldn't believe the irony of this great security solution requesting full access to my machine with a self-signed certificate. I wonder if this actually a psychology experiment to show that even when people are thinking about security that they're still willing to give up the keys to the kingdom as long as you ask nicely and state that you're a "security researcher".

      • I couldn't believe the irony of this great security solution requesting full access to my machine

        No, full access to the files in your user account, not your entire machine. And that's only because unlike the Sugar, Mac OS X, and non-IE JavaScript sandboxes, Java has no concept of a file I/O capability limited to files chosen through a trusted file chooser dialog box.

        with a self-signed certificate

        APKs from unknown sources for Android are likewise self-signed, yet people install them. Heck, people install Windows applications developed by hobbyists even without a signature.

    • by Anonymous Coward

      In reality, something signed by Verisign isn't really any more 'secure' than a self-signed applet.

      Besides, he's working on one little security feature. Why should he implement things that are not directly relevant to what he is researching?

  • by Anonymous Coward on Saturday April 07, 2012 @08:10PM (#39609657)

    WARNING

    My java said that the code was not signed. It could be swapped or faked. Don't run it unless it is signed and verified properly. It also gains full acess to your computer... so don't run it until it is restricted.

  • by Opyros (1153335)
    "released an working prototype" should be "released a working prototype".
    • by Anonymous Coward

      So it has come to this.

  • Tr0ub4dor or Correct Horse Battery Staple?

    https://xkcd.com/936/ [xkcd.com]

  • Too bad it require java support. I removed it since it's security risk overweight its benefit [krebsonsecurity.com]
  • by Anonymous Coward

    Highly suspicious!!! I have just run this. Firstly the site appears to be Russian! Secondly I gave it full access to my computer! Now I don't know what I have compromised. Help ne slashdot, why did you publish this tripe?

  • It seems like all this would do is just decrease the brute force speed since you would have to do image analysis (assuming you could write a decent CAPTCHA solver). How would this be different than passing a password through an algorithm 1000’s of times? Also it seems like it might decrease password security. Depending on what is known about the encrypted data, an attacker may not have any way to check if the password is correct. With the CAPTCHA, I would think it would be quite easy to detect the ch
    • Re: (Score:2, Informative)

      by Anonymous Coward

      Cdxta: This is exactly true - the purpose of the algorithm is to introduce something that in your language would be described as false positives.

      Konstantin

  • by Anonymous Coward

    Folks - thank you for all the comments.

    As far as applet goes - this is a demo prototype for the scientific community to evaluate our algorithm.

    Signing the applet would require formalities + money but would not actually add much security we could put a trojan into a signed applet too.
    We are planning to release our source code soon anyway.

    Our web site and applet are not Google or Facebook :-) Please pardon our dust :-)

    We are looking forward to receiving more comments on the algorithm and paper.

    Thank you,
    Max P

  • by hairyfish (1653411) on Sunday April 08, 2012 @12:35AM (#39610589)
    These stories seem to pop up every week about how we have a new system that is better than a regular password. You can't get better than a regular password because the weakest link in the whole password process is the human. Make the authentication process any more complex and the human becomes an even weaker link. The other big miss that none of these stories never seem to cover (esp biometrics) is that the great strength of a password is its portability. If I need someone to do something on my behalf I can tell them the password and they can do it, and it gets done. This may sound like a weakness on the surface, but the alternative non-portable method would mean all those things wouldn't otherwise have been done, and ultimately systems are designed to do things. Therefore, too strong an authentication makes the overall system less effective. Security is about balance. You can't build a house without doors and windows, and I think the regular old password is the best balance you'll ever get to authentication. Why waste energy trying to build a better mousetrap?
    • Re: (Score:1, Informative)

      by Anonymous Coward

      "You can't get better than a regular password"
      Congratulations, you drivelled your way to a +5 insightful.

      Here's some recent news:
      - we discovered fire -- we can do better than cold!
      - we discovered the wheel -- we can go faster than walking!
      - we discovered shelter -- we can be drier than soaked when it rains!

      Seriously. No really. Seriously.
      A regular password? "12345" is one of the most common ones.
      Letting a 3 month old baby on your keyboard will produce a better password.
      Letting your cat walk over it will pro

    • by Arrepiadd (688829)

      [...] is that the great strength of a password is its portability. If I need someone to do something on my behalf I can tell them the password and they can do it, and it gets done. This may sound like a weakness on the surface, but the alternative non-portable method would mean all those things wouldn't otherwise have been done, and ultimately systems are designed to do things.

      Aren't you extrapolating from posting the latest coolest pic you have on your Facebook account a bit too much?
      If you have a job where security credentials are important and your boss finds out your giving your password so someone else can "get stuff done", you'll find yourself in a bad spot (or you should at least)! There's a reason even Facebook says usernames and passwords are personal... it's because they're meant to be, to protect you (apparently from yourself). Hell, this statement you wrote seems to

  • by goodmanj (234846) on Sunday April 08, 2012 @03:09AM (#39611035)

    Slashdot comments usually contain at least a few insightful comments, but so far people have been going for wisecracks and low-hanging fruit.

    Yes, using a self-signed certificate in a security product is stupid. Yes, trusting physicists to come up with a good encryption scheme is like hiring a plumber to do heart bypass surgery (I am a physicist). But those are boring criticisms. A more interesting question: is the basic idea actually any good?

    If you play with it, it looks like it boils down to using a short easy password to generate a chaotic bit pattern; this bit pattern is XORed against a Captcha image. The result is easy for humans to read. If you try to decrypt with the wrong password, you get a different chaotic bit pattern that can't be read. But a computer has to do a lot of work to figure out if each bit pattern contains readable text or not.

    The goal here is not to increase the entropy of the password, or to use an asymmetric algorithm that's much easier to encode than decode. Instead, they're trying to make each decryption attempt require enough compute cycles that it's impractical to brute-force even a short password.

    The obvious direct attack is to write a very good, very fast captcha detector. It doesn't actually have to be able to *read* the captcha at all: it just has to be able to filter out "obviously doesn't contain text" from "probably contains text", and present the likely candidates to a human for final analysis. Some sort of noisy edge detection algorithm might work well.

    If you hate writing computer vision algorithms, a simple Mechanical Turk approach might also work. If you presented a full-screen grid of 100 candidate decryptions to a human, they could probably identify one that contains text in a couple of seconds. A single human should be able to complete an English dictionary attack in a day.

    • by tepples (727027)

      Yes, using a self-signed certificate in a security product is stupid.

      I will address this assertion as soon as you address the following question: Why do code signing certificates cost more than SSL certificates?

  • I find the idea very interesting, but isn't it sad this approach wouldn't work on a text-based terminal (e.g. an ssh login)?
    • Yes, and what if you are wanting to login to your computer on the TTY virtual console and you type in your username and password. This system would not work then. If you are worrying about the security of your bank account, you could have a mobile phone setup so that it would text message you a code you would need to enter to perform some actions on your account, that does provide some peace of mind. And Captchas are good at cutting spam on the Internet, but they would be annoying on a Linux/UNIX machine.

  • I've just gotten three of them wrong in a row. Also, the input box doesn't appear to always capture the keyboard in Linux.
    • by Teun (17872)
      It takes a while before the input box becomes responsive, have patience.

      I noticed a 195Kb movie file became a 2.2 Mb encrypted file and that's done in Java so some delay does not surprise me.

  • I got sick of getting them wrong all the time. I finally just downloaded a browser plug-in to do them for me.

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