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Scientists Release Working Prototype Of CAPTCHA-Based Password Assistant

timothy posted more than 2 years ago | from the holding-out-for-retinal-scans dept.

Encryption 86

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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86 comments

These amateurs! (-1, Offtopic)

GmExtremacy (2579091) | more than 2 years ago | (#39609559)

These amateurs! These amateurs! These amateurs! These amateurs! These amateurs need to use Gamemaker!

Re:These amateurs! (-1)

Anonymous Coward | more than 2 years ago | (#39610057)

These amateurs! These amateurs! These amateurs! These amateurs! These amateurs need to use Gamemaker!

Does Gamemaker hate niggers? Because I hate niggers. I like black people but I hate me some damn niggers. Don't know the difference? Let a black person explain it to you: Watch and Learn [youtube.com] . See that first comment "I'm black and that's exactly how I feel" he said that instead of whinging about "racism" well AMEN, somebody gets it.

Who else here hates niggers? Anthromorphised Gamemaker? You? Inquiring minds wanna know.

um (1)

msheekhah (903443) | more than 2 years ago | (#39609597)

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:um (3, Informative)

Anonymous Coward | more than 2 years ago | (#39609617)

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 (3, Insightful)

dgatwood (11270) | more than 2 years ago | (#39609917)

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 (3, Interesting)

errandum (2014454) | more than 2 years ago | (#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).

Re:um (1)

WrongSizeGlass (838941) | more than 2 years ago | (#39611611)

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).

Re:um (2)

errandum (2014454) | more than 2 years ago | (#39611993)

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 windows executables, you should not use anything written in C, C++ or windows.

Re:um (1)

dgatwood (11270) | more than 2 years ago | (#39636471)

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 that since C and C++ has been used on viruses that get delivered as windows executables, you should not use anything written in C, C++ or windows.

No, it isn't. Not at all. If you had read the article I linked to, you would understand that the attack was only possible because of actual bugs in Java itself. Not because of code written in Java. Because of bugs in Java.

Re:um (1)

errandum (2014454) | more than 2 years ago | (#39639047)

No, because of bugs in the virtual machine. That runs java. Windows HAS known security bugs. Thousands over the years, I'd say. Anything that runs code (be it a browser - there goes your marvelous html5 file API or Java or the OS) has the potential of running code outside of it's scope. Even the most secure browsers have known exploits (as proven by the recent pwn2own results - http://www.zdnet.com/blog/security/pwn2own-2012-google-chrome-browser-sandbox-first-to-fall/10588 [zdnet.com] - so no, you have no fucking idea of what you're talking about.

Second of all, having Java enabled will not hurt your computer, running a Mac that has java updated by apple might. If you had read the article in the post you linked, you'd see it exploits something Oracle already fixed for other OS's - just not for the mac, since Apple won't let them.

If you won't run Java because it's not safe, then you better uninstall flash (even worse), your browser (that's hard, since you're here!), your OS (remember, viruses won't run in a computer that ain't on). While you're at it, you can breath virus in, so I'd stop breathing altogether. Better safe than sorry!

And nowadays browsers will even ask you if you trust an applet before they run it (Chrome) and will only enable it if you want to. So don't fucking click yes if you're somewhere you don't trust.

Again, it was a ridiculous comment. But I'm sure you'll do your best to up your security by just leaving the internet altogether and doing everyone else (and yourself) a favor. You never know when you might get ridiculed again.

Re:um (0)

Anonymous Coward | more than 2 years ago | (#39610263)

Right...I'm supposed to allow a Russian site to run Java script on my machine. Do I look like I just stepped out of Best Buy?

Re:um (3, Insightful)

tepples (727027) | more than 2 years ago | (#39611151)

First, it's Java, not JavaScript. Second, if you've installed Kaspersky AV or any ElcomSoft product or even played Tetris®, you've run Russian code on your machine.

Re:um (4, Funny)

theshowmecanuck (703852) | more than 2 years ago | (#39610437)

I heard a story about a virus written in C. That's why I'm writing this on Slashdot with an abacus.

Re:um (3, Interesting)

Patch86 (1465427) | more than 2 years ago | (#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.

Re:um (1)

hi-endian (2589843) | more than 2 years ago | (#39613157)

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

They don't.

Re:um (1)

timothyb89 (1259272) | more than 2 years ago | (#39609633)

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.

Re:um (2)

Martin Blank (154261) | more than 2 years ago | (#39610167)

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 (3, Interesting)

Patch86 (1465427) | more than 2 years ago | (#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).

Re:um (1)

Martin Blank (154261) | more than 2 years ago | (#39614411)

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.

joke (-1)

Anonymous Coward | more than 2 years ago | (#39609607)

Wow ! This glorified captcha + password makes a fool's day joke for the second year straight. What inexhaustible scientists these are ! :-)

is there any good analysis in the year since? (4, Insightful)

Trepidity (597) | more than 2 years ago | (#39609621)

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:is there any good analysis in the year since? (1, Informative)

Anonymous Coward | more than 2 years ago | (#39609681)

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

Requires self-signed applet with full privileges (4, Interesting)

Plouf (957367) | more than 2 years ago | (#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.

Re:Requires self-signed applet with full privilege (4, Informative)

Anonymous Coward | more than 2 years ago | (#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:Requires self-signed applet with full privilege (2, Funny)

Anonymous Coward | more than 2 years ago | (#39609939)

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

Re:Requires self-signed applet with full privilege (2, Interesting)

Anonymous Coward | more than 2 years ago | (#39610011)

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.

Re:Requires self-signed applet with full privilege (1)

WrongSizeGlass (838941) | more than 2 years ago | (#39611633)

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.

Re:Requires self-signed applet with full privilege (1)

krrose27 (2612933) | more than 2 years ago | (#39616919)

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 blanket that they aren't trying to hide anything. Since they chose to deliver it in the fashion they did everyone flipped out. As a java dev I see where they are coming from and wanted to make the point that they aren't doing anything fishy and could be easily checked on. Just logical.

Re:Requires self-signed applet with full privilege (1)

Anonymous Coward | more than 2 years ago | (#39609965)

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?

Re:Requires self-signed applet with full privilege (0)

Anonymous Coward | more than 2 years ago | (#39610121)

The files are not uploaded anywhere - they are encrypted locally. We do not want information uploaded anywhere.

Re:Requires self-signed applet with full privilege (2)

tepples (727027) | more than 2 years ago | (#39611167)

So you want it to work offline; that's commendable. But why not offer it as a downloadable, double-clickable jar so that it'll already have the needed capabilities?

Re:Requires self-signed applet with full privilege (2)

netsharc (195805) | more than 2 years ago | (#39610007)

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

Re:Requires self-signed applet with full privilege (5, Interesting)

FrootLoops (1817694) | more than 2 years ago | (#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.

Certificate price gap (1)

tepples (727027) | more than 2 years ago | (#39611303)

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?

Re:Certificate price gap (1)

FrootLoops (1817694) | more than 2 years ago | (#39611369)

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!"

Re:Certificate price gap (1)

mrmeval (662166) | more than 2 years ago | (#39611625)

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.

Re:Certificate price gap (2)

WrongSizeGlass (838941) | more than 2 years ago | (#39611689)

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 you won't ever forget.

Re:Requires self-signed applet with full privilege (1)

hankwang (413283) | more than 2 years ago | (#39613199)

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 (Montenegro) domain requires proof of identity, though.

Re:Requires self-signed applet with full privilege (1)

ignavus (213578) | more than 2 years ago | (#39616599)

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 /.

Re:Requires self-signed applet with full privilege (5, Insightful)

SashaMan (263632) | more than 2 years ago | (#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".

So does Android (1)

tepples (727027) | more than 2 years ago | (#39611295)

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.

Re:Requires self-signed applet with full privilege (1)

Anonymous Coward | more than 2 years ago | (#39610077)

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?

Re:Requires self-signed applet with full privilege (0)

Anonymous Coward | more than 2 years ago | (#39610101)

Sure, I'll let your app do whatever it wants . . .

No problem!

I'm be back as soon as I get done sending this money order to a Nigerian prince that I'm apparently related to.

NOT SIGNED code, could be harmfull (3, Interesting)

Anonymous Coward | more than 2 years ago | (#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.

Re:NOT SIGNED code, could be harmfull (-1)

Anonymous Coward | more than 2 years ago | (#39609695)

Folks - I already explained - it needs the permissions to read the files. There is no way to fix it - this is the way Java works

What we wanted is to have an online demo for people to try it - Java was pretty much the only option

It is actually quite secure - everything happens in the browser, nothing is communicated back to the server.

Konstantin

Re:NOT SIGNED code, could be harmfull (0)

Anonymous Coward | more than 2 years ago | (#39609841)

it is not signed.. I don't even know that it is what was intended, or that there might be a man-in-the-middle attack...

Don't RUN IT.

Not decompiled either, I take it (1)

tepples (727027) | more than 2 years ago | (#39611273)

It's in Java, and Java bytecode decompiles much more cleanly than, say, x86 bytecode compiled from C. Did you try decompiling it and reading the resulting source code? If not, why not?

Re:Not decompiled either, I take it (2)

WrongSizeGlass (838941) | more than 2 years ago | (#39611651)

It's in Java, and Java bytecode decompiles much more cleanly than, say, x86 bytecode compiled from C. Did you try decompiling it and reading the resulting source code? If not, why not?

Decompiling & inspecting code every time it is downloaded or updated is not a realistic solution before trusting or running code. Especially not for the vast vast majority of internet users who don't know any programming language, let alone Java.

CA-signed software not audited either (1)

tepples (727027) | more than 2 years ago | (#39612101)

I thought the whole point of distributing software as source code (or in a form from which source code could be easily derived) was that it could be audited. If this auditing turns out to not in fact take place, then how does any program from any author prove itself trustworthy? A CA-signed certificate is not the answer because the CAs don't do this auditing either. OLPC Bitfrost and Mac OS X's sandbox get it right: the operating system provides trusted file choosers to authorize access to individual files and folders.

Re:NOT SIGNED code, could be harmfull (0)

Anonymous Coward | more than 2 years ago | (#39610103)

So you think paying some crook like Verisign money means that the code is safe? That is Microsoft-level naivety there.

Re:NOT SIGNED code, could be harmfull (0)

Anonymous Coward | more than 2 years ago | (#39611219)

Nope, but at least it means it is likely to have come from the original authors and not been tampered with along the way.

Re:NOT SIGNED code, could be harmfull (1)

tepples (727027) | more than 2 years ago | (#39611271)

In the current certificate market, wouldn't HTTPS be a cheaper way to verify integrity of the jar than a code signing certificate? Ideally, SSL certificates and code signing certificates should cost the same, but there are market failures in the way.

Typo (0)

Opyros (1153335) | more than 2 years ago | (#39609667)

"released an working prototype" should be "released a working prototype".

Re:Typo (1)

Anonymous Coward | more than 2 years ago | (#39609717)

So it has come to this.

Re:Typo (0)

Anonymous Coward | more than 2 years ago | (#39609933)

Should be changed to a non-working prototype. Because the applet wants privileges that it doesn't need, it needs permission to run. And because the applet is self-signed I can't grant that permission. (Not that I would be stupid enough to do that anyway. Java applets need to stay in their sandbox.)

Flash Back problem (0)

Anonymous Coward | more than 2 years ago | (#39609775)

Is this really worth trying, in exchange for being susceptible to Flash Back?

Yuk.... (0)

Anonymous Coward | more than 2 years ago | (#39609823)

Java.....somebody is always poking around at my sandbox.

Stong? What is strong? (1)

Ralph Spoilsport (673134) | more than 2 years ago | (#39609853)

Tr0ub4dor or Correct Horse Battery Staple?

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

Find something better to do (0)

_xanthus_47 (2612937) | more than 2 years ago | (#39610133)

Why are scientists from a physics institute developing password encryption techniques??? Surely they MUST have something else better to do..

Re:Find something better to do (0)

Anonymous Coward | more than 2 years ago | (#39610163)

Because they are smart - World Wide Web was developed by physicists at CERN

Highly Suss!!! (1)

Anonymous Coward | more than 2 years ago | (#39610275)

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?

Interesting (2)

cdxta (1170917) | more than 2 years ago | (#39610341)

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 characters that are out of the norm of randomness even if you can’t tell the letters and pass it to a human or deeper scan. That is unless there are false positive CAPTCHA outputs?

Re:Interesting (2, Informative)

Anonymous Coward | more than 2 years ago | (#39610579)

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

Crypto Flow (1)

NicknameAvailable (2581237) | more than 2 years ago | (#39610475)

I haven't checked how this works (don't see a direct link to it anywhere) - but from using the demo it looks like the crypto piping is: Data --> Encrypt by CAPTCHA --> Encrypt by password --> Decrypt by password --> Decrypt by CAPTCHA --> Data Seems like a cool idea to prevent brute forcing.

Thank you from the Max Planck Group (1)

Anonymous Coward | more than 2 years ago | (#39610537)

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 Planck group

Re:Thank you from the Max Planck Group (0)

Anonymous Coward | more than 2 years ago | (#39611061)

So. This is released on a .me domain. Sourced from an anonymous reader. During a rage of Java plugin exploits.
    Timothy, you are, now beyond a doubt, a fucking idiot.
    BTW, what do you actually do for a living?

A better mousetrap? (3, Insightful)

hairyfish (1653411) | more than 2 years ago | (#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:A better mousetrap? (1, Informative)

Anonymous Coward | more than 2 years ago | (#39611325)

"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 produce a better password.
Picking random words from a dictionary will produce better passwords.
Using your s.o.'s birthdate will produce a better password (and may prevent a source of relationship worry). It is really hard not to do better than a regular password. Even Spaceballs recognised how bad regular passwords are.

Anything we do for better passwords will actually result in (slightly) better passwords -- the state of "regular" passwords is that sorry.
The interesting question (that the researchers approached creatively) is how to improve passwords in a human-friendly way.

Your comment is just wrong on so many levels, it's scary.

Re:A better mousetrap? (1)

Arrepiadd (688829) | more than 2 years ago | (#39611433)

[...] 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 me the best reason to go on and implement biometric style authentication. At least people will stop giving their passwords to others... Do you also give people access to your bank account because you need them to do something for you? And you sleep comfortable after that?

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?

And since when what you think is law? World seemed to work pretty well in 1904 and yet, by 1905, a certain guy named Einstein had proved there was a speed limit (among other things). Why did he even waste energy thinking about that when we clearly cannot even go beyond the nearest rock?

TEST (0)

Anonymous Coward | more than 2 years ago | (#39610831)

First thought: Don't use a currently-in-use password, just like; don't randomly write one's name on a piece of paper.

It converted a 6 KB plain-text file to a 2024 KB cipher-text file. Also, I had to close my browser/Java and start it again before the CAPTTHA would work. It seems Java keeps a file-lock on the encrypted file.

Can someone explain the concept? (0)

Anonymous Coward | more than 2 years ago | (#39610927)

Tried it out. Don't get the point.
Before I did try it, this is how I envisioned it:
Let's say someone is trying to get into a drum website and they use a word association like Drum to "Beat" to "Beating a dead h0arse thro@t"
It might be more easily cracked than using the word Butterfly to "Presto Change-(My Flat T!re)"
I thought this process would somehow securely yield up the word Butterfly at the end to help you remember this particular password.
Not it at all.

Enough wisecracks, let's start thinking. (5, Insightful)

goodmanj (234846) | more than 2 years ago | (#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.

Re:Enough wisecracks, let's start thinking. (2)

tepples (727027) | more than 2 years ago | (#39611281)

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?

Re:Enough wisecracks, let's start thinking. (0)

Anonymous Coward | more than 2 years ago | (#39611289)

Developments to defeat CAPTCHA's are improving all the time.
There have already been several notable stories about CATCHPA's being defeated using automated means.
Would you really trust a system that relies on CAPTCHA's?

Sure you could make the base password longer, but then what's the point?

Re:Enough wisecracks, let's start thinking. (1)

goodmanj (234846) | more than 2 years ago | (#39614009)

The idea is to multiply the complexity of solving a captcha with the complexity of solving a password to give a problem that's far harder than either one alone.

With captchas alone, if you can defeat a captcha in 10 seconds, you win. With passwords alone, if you can try a single entry in a 10 million-word dictionary every microsecond, you win in 10 seconds. But if each dictionary attempt requires you to solve a captcha, you still win ... in 3 years of computing time.

It all boils down to, "how long does it really take to solve a captcha?" And yeah, I'm not sure it's long enough, but we'd have to work the numbers to be sure.

Where's the security? (0)

Anonymous Coward | more than 2 years ago | (#39611317)

I fail to see the security here. I don't see the point of the "chaotic lattice system". What I see is a usual CAPTCHA image on what appears to be a random dotted background. But since it's quite easy for me to tell out the letters, I suspect this is quite easy for a computer too, especially given this type of CAPTCHA doesn't appear to be harder than other CAPTCHA's. Of course you could argue that it might be computationally demanding solving these CAPTCHAs. However, if that's the property you are looking for you use an iterated hash in the password scheme (i.e. have the file be encrypted by a random key stored in the header, which has been encrypted N times with the provided password etc.).

Again, I don't see any magic value added by the chaotic lattice system. I think the security would be equivalent to simply generating some random noise using any secure PRNG seeded with key K and then store that K encrypted under the user password and store the file content encrypted under K and password.

Doesn't work in CLI (2)

billcarson (2438218) | more than 2 years ago | (#39611411)

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)?

Re:Doesn't work in CLI (1)

bejiitas_wrath (825021) | more than 2 years ago | (#39611829)

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.

Captcha is horrendous (2)

Arabian Nights (2597797) | more than 2 years ago | (#39612065)

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.

Re:Captcha is horrendous (1)

Teun (17872) | more than 2 years ago | (#39612309)

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 hate CAPTCHA (1)

locopuyo (1433631) | more than 2 years ago | (#39616255)

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

Applet to be signed tomorrow (0)

Anonymous Coward | more than 2 years ago | (#39616845)

Folks - due to the popular demand we are getting a code signing cert - hopefully as early as tomorrow the applet will be signed.

We also put doPrivileged() calls into the applet and removed the "permit all" policy

Konstantin

To frootloops (0)

Anonymous Coward | more than 2 years ago | (#39616867)

FrootLoops - contrary to your comments I am not as young as you think. I did postdoc at Los Alamos and Stanford. I was also an early member of Sun Java Virtual Machine team. Believe me I do know lots of things about Java.

As far as my writing style in concerned - I think living in Silicon Valley for a looong time has put a stamp on me as well as communicating with too many great smart positive people. I am positive and want to communicate with positive people. And I do like using smileys in my writings :-))) I

If I am mistaken for a teenager - this is the greatest thing I could wish for :-)

Konstantin

Decompiled and Tested, not a virus. (0)

Anonymous Coward | more than 2 years ago | (#39622019)

I went ahead and decompiled the packages nl.captcha.* and com.jhlabs.* and there seems to be no references to AtomicReferenceArray nor any non-local URLs meaning this application doesn't download anything from a remote source and doesn't seem to be a currently known JVM exploit.

Feel free to check it yourself.

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