3D-Based CAPTCHAs Become a Reality 192
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."
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:Practically cracked already (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.
Won't work. Where will you get your pictures of Siamese Cats? If you take them yourself, you'll only have a few. Spammers will simply train their bots to recognize these cats.
If you have lots of pictures of cat and non-cat objects, the attacker has two strategies: either he can get the same database you did (which you didn't make, because making a large enough database would be cost-prohibitive), or failing that, he just trains his image recognized to pick out characteristics of Siamese cats the same way a human brain would.
You know enough that recognizing 3D shapes is a solved problem; doesn't it seem clear that recognizing textures would be just as tractable?
And I imagine you could create tough cases, but these cases will also trip up human beings.
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.