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3D-Based CAPTCHAs Become a Reality
Posted by
Soulskill
on Fri Mar 27, 2009 08:16 PM
from the is-that-an-e-wait-i-think-it's-a-5-dangit-let-me-in dept.
from the is-that-an-e-wait-i-think-it's-a-5-dangit-let-me-in dept.
mateuscb writes "A new way of creating a CAPTCHA using 3D objects has become a reality. The idea was thought up independently by blogger Taylor Hayward and by the folks at YUNiTi.com. 'Similar to Hayward's idea, this new technology relies on our ability to identify objects in 3D instead of using alphanumeric characters. YUNiti's 3D Captcha, however, has three objects in the challenge and extends the list of images to any object, not limiting it to animals as in Hayward's idea. This increases the challenge's level of complication to prevent computers from successfully making the correct guesses.' I, for one, welcome the thought of not having to read more and more complex CAPTCHA. Lately, I've been having a hard time getting CAPTCHA to work the first time."
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Why the CAPTCHA Approach Is Doomed 522 comments
TechnoBabble Pro writes "The CAPTCHA idea sounds simple: prevent bots from massively abusing a website (e.g. to get many email or social network accounts, and send spam), by giving users a test which is easy for humans, but impossible for computers. Is there really such a thing as a well-balanced CAPTCHA, easy on human eyes, but tough on bots? TechnoBabble Pro has a piece on 3 CAPTCHA gotchas which show why any puzzle which isn't a nuisance to legitimate users, won't be much hindrance to abusers, either. It looks like we need a different approach to stop the bots."
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3D? Pfft. (Score:2, Funny)
I want 4D CAPTCHAs, so even humans can't figure them out. Think... Hypercube... the CAPTCHA.
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Re:3D? Pfft. (Score:4, Insightful)
Pfft. Mere mortal.
Kinda defeats the purpose of a captcha if it looks like noise to a human, but is solvable by a computer.
Parent
Re: (Score:3, Funny)
So... you get access to the site, and then the CAPTCHA kills you?
4D? Pfft. (Score:5, Funny)
If you wanna post on my site, you better be prepared to solve the 5D hyper-hyper-cube [gravitation3d.com]!
Parent
First time? (Score:5, Funny)
I've been having a hard time getting CAPTCHA to work the first time.
And the secondtime . And the third time. And the fourth. And the....
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Maybe he should try his luck on this [wikipedia.org].
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Actually I wonder how this captcha holds up against basic neural net analysis. How much do they offer these days for captcha crackers ? It looks like it's basically a silhouette, I expect this will do a lot worse (due to less combinations) than "normal" scrambled letters captchas.
The price has really been going down on captcha crackers. Every idiot and his mother are making them these days. Lots of indians losing jobs ...
The sad thing is, my own captcha crackers are much better at solving captchas than my o
Re:First time? (Score:5, Funny)
Parent
Re:First time? (Score:5, Funny)
Parent
Re:First time? (Score:4, Funny)
So what you're saying is, right, that all of this has happened before and all of this will happen again?
Parent
Re:First time? (Score:5, Funny)
I've been having a hard time getting CAPTCHA to work the first time.
And the secondtime . And the third time. And the fourth. And the....
I was having trouble too, until I found this awesome piece of software that solves CAPTCHAs for me. It even automatically finds the CAPTCHA image and text entry field so that I don't even have to be bothered by it. ;)
Parent
Rationality check (Score:4, Insightful)
Let's see now. If the spammers and robot makers went outside, done something worthwhile and produced something the world badly needs (food) then this nonsense wouldn't exist, I could surf in peace and the starving millions would live a little longer. The very existence of CAPTCHA's proves the human race is badly in need of a reset.
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Parent nailed it.
It's all the spammer's fault that we waste time on captchas.
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They'll send it off to porn sites or whatever and have people analyse it from there - can always get around them, it is just a question of resources.
Re:Rationality check (Score:5, Insightful)
Such is the way of all intelligent life, though. If you build a maze for a mouse, the rodent may run its course a thousand times to reach the end and its reward. But never be fooled for a second: the mouse likes the cheese, not the maze. If he finds a way to climb over the walls and skip the test entirely, you should be neither surprised nor angry, as the failure is yours.
Parent
Re:Rationality check (Score:5, Insightful)
Parent
Humans can defeat humans (Score:5, Informative)
Interesting, but in a previous /. discussion, I got convinced that there was no perfect captcha, since one can simply pay a group of underpaid workers (e.g. in poor country) to manually solve the captchas...
Re:Humans can defeat humans (Score:5, Interesting)
It's much worse than that. Put up a porn site. Use free content. Have a "Solve captcha to get free pics!" blocker.
Now, grab a captcha you want to break, show to pornaholics, get solution, pass it back to the original site.
Perfectly unbeatable captcha solving, for virtually free, and totally automated.
Feh.
Parent
Re:Humans can defeat humans (Score:5, Funny)
Parent
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Like steering and changing gear?
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like following a simple rhythm.
Dear god! Like I don't fail captchas enough without adding in my rhythm-less whiteness to the equation!
Re:Humans can defeat humans (Score:5, Interesting)
That's very true. The problem now isn't rendering CAPTCHAs useless, it's doing so by automated means.
As you said, anything that must be used by humans can be broken by humans. But you still wind up with logistics problems--having the money to pay these people (or, in the case of free porn, the bandwidth and content to keep them interested) and the fact that those people are still limited by their humanity. Even the fastest typist wouldn't be able to complete a form (CAPTCHA aside) as quick as a robot. And, if a robot can break a CAPTCHA, it can fill that out faster than a human, as well.
So the issue is preventing, or at least slowing down, robots, which can work 24/7 without a break. A variety of things have been done with normal CAPTCHAs to do this: colors, lines, running letters into each other, adding cats and dogs to letters (seriously). This step, once "perfected" and widely adopted, will be a huge leap in stopping these robots. Even if they can be trained to have a copy of the exact 3D models given (which are sure to increase in variety if not types), they still have to take a picture of it from every single angle, which I believe is 359^3 images, and then compare every single one (which is O(x^n) time, where x is the time for one image comparison).
It's an arm's race, though. Eventually some enterprising hacker will figure out a way for bots to "guesstimate" based on various aspects of an image, and once that solution is sold to the highest bidder we start the war all over again.
Parent
Re: (Score:3, Interesting)
One, 359^3 leaves out rotations on multiple axes.
Two, even including that, though, you don't need every degree along each axis of rotation, you could probably get by with eighths or maybe even quarter rotations if current machine vision techniques are used. I've seen optical testers that could identify a particular object rotated along one axis with just one "quality ideal" reference photo and tests a few hundred objects/second. Not angles, objects. Spits them out like a machine gun.
Re: (Score:3, Funny)
Actually, I don't think there are any arms racing here, though I could be wrong. That kind of race sounds boring, anyway.
Re: (Score:3, Interesting)
From the rReCAPTCHA FAQ
Are CAPTCHAs secure? I heard spammers are using porn sites to solve them: the CAPTCHAs are sent to a porn site, and the porn site users are asked to solve the CAPTCHA before being able to see a pornographic image.
CAPTCHAs offer great protection against abuse from automated programs. While it might be the case that some spammers have started using porn sites to attack CAPTCHAs (although there is no recorded evidence of this), the amount of damage this can inflict is tiny (so tiny that
Re:Humans can defeat humans (Score:5, Insightful)
If it requires actual workers, then it is a perfectly working CAPTCHA. "Completely Automated Public Turing test to tell Computers and Humans Apart." Don't think of it as a way to keep bad posts from your forum, because it isn't. It just tries to increase the likelihood that a human was involved in the process. If you want to limit abuse, getting a guarantee that a human was involved is only one small step in the process.
Parent
Re:Humans can defeat humans (Score:5, Insightful)
If the spammers have to pay to spam, we've already won.
Parent
Hmmm, not bad (Score:2)
You can easily generate new images by rotating the 3D model a bit, changing the lighting, colors, etc.
The Question and Answer images could be generated the same way. You have to constrain the camera a bit so it isn't "What kind of animal has this butt?", but other than that you have a very large space to grab from.
Still doesn't solve the "porn for captcha" hack, but this would tell humans and computers apart for a while.
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Yet, at the same time there is just as much, and probably more effort going into image analysis. How many universities are currently working on automated vehicles that have some sort of system for analyzing and identifying objects in it's path, or even simple worker-bots that can tell between a coffee cup and a stapler.
Once that's established, all it would take is a couple manual hours to put the images into a 'like' groups, that could be done with the porn-hack.
I still think a story-based system would work
object recognition (Score:3, Interesting)
I dunno, there has been quite a bit of research done with image/object recognition. You could break this by not matching pictures directly but by seeing that the first one is a bunny (so look for a bunny in the list), the second one is a hammer, etc...
Great! (Score:2)
We need something different. Personally, I can't comprehend 2D captchas. I think I might be an android, pre-programmed with false memories of childhood.
This 3D technology will finally help me solve this existential issue.
(BRB, gotta go recharge)
Obvious, not innovative (Score:2)
What's next, an "innovation" because it plays a (readily recognizable to the target audience) music sample? Same idea you know.
And I bet blind people are driven baty with CAPTCHAS anyway, this just makes web pages even less accessible to them.
This Is Great for Progress in AI (Score:3, Insightful)
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Easy to defeat (Score:4, Insightful)
As is, this seems relatively easy to defeat and well within reach of available technology. The number of 3D models is rather low and they have a very clear silhouette and also a very distinct one for each models. So all one has to do is to search for the best matching silhouette.
The good thing however is that 3d models have enough flexibility so that one could conquer many attacks, adding background images and texture would make it much more difficult to get a clear silhouette and one could of course easily introduce many more models into the mix.
Re:Easy to defeat (Score:4, Interesting)
They were all pretty easy except for the toilet. I assume it's the lower left one in the grid, but I had to work it out by elimination.
Parent
Instructions (Score:2)
"It's a sailboat" (Score:2)
An Alternative (Score:4, Insightful)
And put it on YouTube afterwards.
First Cylon... (Score:4, Funny)
It's becoming more evident every day that the first cylon will be a Captcha solver.
It won't be too long before Captchas will be little reading comprehension tests like on a 3rd grade social studies test.
After that we'll just have to revert to empathic testing. Sadly those with Autistic Spectrum Disorders will no longer be able to use webmail.
3D recognition is a solveable problem. (Score:3, Informative)
3D recognition is a solveable problem. As someone else mentioned, there are machine learning techniques that work. Recognizing a 3D object from multiple angles is a very old AI problem, one that DoD-funded work was addressing as early as the 1960s. It's easier than 3D reconstruction from multiple 2D images, which is a commercially available technology.
I think we're reaching the end of the line on CAPCHAs. There's now overlap between the smarter vision programs and the dumber users.
They must be Runescape players (Score:5, Interesting)
So Jagex's Runescape MMORPG has had this for a couple of years in random events to defeat macros.
http://www.runescape.com/ [runescape.com]
A few common CAPTCHA fallacies (Score:5, Insightful)
Everyone has a great idea for a CAPTCHA, but very few people know what the hell is really going on. Remember that the machine doesn't need to solve the CAPTCHA every time, that machines are infinitely patient and have huge memories, and that another machine needs to make sure the human gave the right answer!
Ideas that won't work:
Really, it's very easy to think you've come up with a very clever CAPTCHA. When you think that, all you've done is stoked your ego and screwed yourself over. It's the same reason why we don't roll our own cryptography: CAPTCHA-making is a very hard problem, mainly because your problem space must be infinite (to avoid an attacking machine simply memorizing answers), the answers verifiable by a machine, but the problems not solvable by a machine.
How many questions can be checked by machines but not answered by them?
Not many; fewer every day. There are no questions that can't be answered by a computer (and which can be answered by a human mind). The Church-Turing thesis [wikipedia.org] has some validity: the human mind is no more powerful than a turing machine, and ultimately, computers and our brains are equivalently computationally. There's nothing a computer can't solve: there are just things we haven't figured out yet.
Parent
More notes (Score:3, Insightful)
Oh, and there are problems computers can't (easily) solve, but can verify [wikipedia.org]. The problem is that human brains can't solve these problems either!
Before someone jumps in with "humans can solve the halting problem!" -- we really can't. There are problems that obviously halt, and programs that obviously don't. We can tell these apart, but so can computers. It's the complicated, borderline cases that trip up both people and computers.
Furthermore, there are important caveats to the halting problem: first, you can t
Re: (Score:3, Informative)
It's worse than that, actually. Remember, a machine doesn't need to pass the captcha every time. You only need to worry about re-training your image recognizer when the success rate falls below a useful level, and even very low levels of CAPTCHA success are useful for spammers.
Wo
Re: (Score:3, Funny)
It appears you overcame that obstacle