The Foolproof Captcha: Advanced Math



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Like others have said, the math portion wouldn't slow down an OCR bot very long.  There are better ways to do captchas & bot screenings.  I regularly visit sites that used a skewed text captcha and end up failing because the letters are completely illegible.  A computer could figure out what characters those are supposed to be better than I could, I'm sure. 

Use common human logic, insert delays that barely affect human users but would have exponentially more effect on a bot. It defeats the purpose of these devices when it frustrates potential users and does nothing more than delay entry until the next bot adaptation.



Honestly bots could probably solve that faster.



This would be a great way to get me to stop wasting my time posting on forums, as I've never learned any advanced math, and it's been a long time since I've done anything more than basic math in my daily life. Looking at the equation gets some gears in my head turning, but not enough to solve it.

Does seem like a good way to stop people who don't know math from posting (I'm sure some forums could use that, heh), but that doesn't seem like something that could stop bots. I mean, computers are generally pretty good at that math stuff... so I hear.

I saw a good captcha once, I liked that asked how many cats were in a randomly generated picture of animals.



Computers are pretty good at math, but they are not that good recognizing data from images.



I've got a forum dedicated to a certain type of car, and an add-on to this forum software that lets me  force new users to correctly answer any question I choose before they can register. Since the forum is dedicated to one car in particular I simply ask a question about that car (IE "Name one of the engines available in this car", or "name a trim level this car was available in", or something like that). Since anyone looking to join my forum for legitimate reasons would know this answer while any spam bot wouldn't even know what I was asking, much less the answer to the question, it has served me well for keeping spam out. The answer would be readily available via google for any human spammers, but they're generally in a hurry and would rather move on to the next site rather than waste time figuring out how to get into mine.


Something like this could work for a larger site, like Maximum PC as well. Stupid questions like "What is the tag line under the title of the magazine" (Minimum BS), or "What is the highest honour a product can receive in a review" (Kick Ass!") that anybody who would join this website for legitimate reasons woudl know, would stymie Chinese shoe sellers...



the complexity of the captcha should be related to or proportional to the importance of a thread. this prevents idiots below a certain degree of intelligence from posting pointless comments



This kind of protection will keep the site not only save from spam, but from ME to :) xaaxxa There is no freaking way I can solve that :) Not math person like at ALL!



LOL Screw that.



What about those of us who can only do basic math, ie: addition & subtraction?



I agree with what others have said already, OCR + a computers ability to do math, doesn't seem too effective.  I think a better solution would be capthca fill in the blank, like a picture would say "grass color is_____" and the response green would allow you to continue, so common spam bots would have to develop logic since OCR would just copy the initial phrase. Just an idea.



Putting up a Captcha using the one thing that computers excel at....math. Come on...computers were designed to do this stuff easily and fast from the get go. Like others have said, bots will just use wolfram alpha or something and get into it even faster then they do the others.



Captchas suck, but they are a necessary evil, because filters just do not work well enough. Google's reCaptcha service works well enough, there is no need to replace it. Yes, there are services like captchatrader (referral link), however, that still requires the spammers to at the very least pay for captcha solutions (which are solved by other people).



This is the kind of spam protection I'd expect from XKCD



Zachary K.

too bad the "riffraf" has access to wolfram alpha, oh and bots do to.



It takes me at least 10 seconds to do a simple derivative and several minutes to do substitution or decomposition integrals. Wolfram Alpha, on the other hand, can do a second-order differential equation in a sixth of a second. And one second for OCR software, and you're looking at less than 2 seconds per captcha bypass. This captcha would work great if, no matter your answer, after a minute it says "Hey, it took you longer than 5 seconds to solve, so you're a human".



but then if this was implemented, no americans can answer it



Actually, I think the woman that was part of the 15 most influential tech woman could do it...oh and my brother. You nitwit.



answer is 0



I was going to guess; 42. ;)



when you think about it carefully, its very simple. it is just asking for the derivitive of a constant.



the answer is still zero, but you need to determine the derivative before applying the x.

In this case, the derivative is 2cos(2x-pi/2), and putting in 2pi, 2cos(4pi-pi/2)=2cos(-pi/2)=0

but wolfram would solve it in much less time


MdX MaxX

I could probably solve it by hand in less time than it could take me to find and download Wolfram Alpha.

But not everyone takes calculus...



I'm still in Algebra 2...sigh. Although I'm the only one in junior high going to the high school for math! YAY.

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