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CAPTCHA vs skill-testing question

Posted: Fri Oct 23, 2009 6:31 pm
by Darth Wong
What do you think is more effective? Everyone uses CAPTCHAs nowadays, and the skill-testing math question is not as popular, in part because it really doesn't work: you can take a simple math question like "4 * 7 - 18 = " and just plug it into Google for an answer, so a bot can do the same.

But skill-testing word math problems are a little more effective. On my forum I use the following word problem: "Joe Redneck is driving at 75 mph to his meth dealer 51 miles away. How many minutes will it take?" I don't seem to have much trouble with automated sign-ups.

If I Google that, I actually get a couple of hits on people asking for the answer, which is pretty sad (come on, how retarded do you have to be in order to need help with that question?), but I don't think an automated system will figure it out. Not unless a human hard-codes it. Has anyone else tried using skill-testing questions instead of a fancier CAPTCHA?

Re: CAPTCHA vs skill-testing question

Posted: Fri Oct 23, 2009 6:42 pm
by ToonArmy
I'm still using the image CAPTCHA, although the internal university network is exempt which deals with most of our registrations.

Looks like you need a harder question: http://www.wolframalpha.com/input/?i=Jo ... it+take%3F

Re: CAPTCHA vs skill-testing question

Posted: Fri Oct 23, 2009 9:14 pm
by Rotsblok
Just read an article about dutch scientists making a sort of neural search engine (similar like how we think etc) so that the awnsers are more inline of what you expect to find.. So with this new "engine" i think it's more likely to find the anwser...

Note they are also working on search for media like photo's and video's

So I think although you have a nice skill tester, i think in the end it's broken.. but on the other hand anything made by man can be broken.. :P

But that's all in the future..

I think something will be nice if even the possible captcha's rotate.. like at one time you have the image captcha some time later you have the sortable captcha and so on.. So it's even harder to to say well we use this captcha cracker cos you dont know what you encounter...

Re: CAPTCHA vs skill-testing question

Posted: Sat Oct 31, 2009 10:14 am
by Kellanved
Rotsblok wrote:
I think something will be nice if even the possible captcha's rotate.. like at one time you have the image captcha some time later you have the sortable captcha and so on.. So it's even harder to to say well we use this captcha cracker cos you dont know what you encounter...
No, such a chain of captchas is only as strong as its weakest link. They just wait for the captcha they can crack, ignoring the harder questions.

Re: CAPTCHA vs skill-testing question

Posted: Sat Oct 31, 2009 2:56 pm
by battye
Darth Wong wrote:But skill-testing word math problems are a little more effective. On my forum I use the following word problem: "Joe Redneck is driving at 75 mph to his meth dealer 51 miles away. How many minutes will it take?" I don't seem to have much trouble with automated sign-ups.

If I Google that, I actually get a couple of hits on people asking for the answer, which is pretty sad (come on, how retarded do you have to be in order to need help with that question?)
Unless you've made a typo or I'm missing something bleedingly obvious, who could come up with an answer to that in their head? The answer has a decimal in it for a start. If it was rounded to 50, sure. But 51?

Re: CAPTCHA vs skill-testing question

Posted: Sat Oct 31, 2009 5:28 pm
by Sam
The problem with 'skill based' questions is that, unfortunately, some people don't have the skills necessary to answer them. People also don't want to pull out a calculator (or realize Windows and Google both have one built right in) to register for a forum.

Image bases CAPTCHAs bring up a variety of issues, such as accessibly for people who are blind (and in many cases people who aren't blind). When bots are solving captcha more effectively then humans are, we have some major issues here.

I am currently working on a CAPTCHA plug for 3.0.6 that will utilize the textCAPTCHA service:
http://www.phpbb.com/community/viewtopi ... &t=1832305
I actually plan to use this on my own websites, CAPCHAs generally anger me, and potential members, after the 2nd or 3rd failure.

Re: CAPTCHA vs skill-testing question

Posted: Sun Nov 01, 2009 7:08 pm
by Cpt. Blackbeard
I tried the harder CAPTCHAS in 3.0.5 and more Spammers get in then regular users, who just get frustrated and quit so I went back to the older CAPTCHA settings and made Registered users a read only group for screening. Last night I found a great thread here on antispam and added a question box to the registration, one new real sign up and no Spam yet so I have my hopes up. CAPTCHA is a step in the wrong direction I think.

Re: CAPTCHA vs skill-testing question

Posted: Sun Nov 01, 2009 7:43 pm
by Roberdin
Anyone who is not particularly numerically-orientated will not be interested in attempting to solve that problem.

Re: CAPTCHA vs skill-testing question

Posted: Sun Nov 01, 2009 9:06 pm
by Darth Wong
SyntaxError90 wrote:The problem with 'skill based' questions is that, unfortunately, some people don't have the skills necessary to answer them. People also don't want to pull out a calculator (or realize Windows and Google both have one built right in) to register for a forum.
I suppose it depends on whether you want that kind of user to enter. To be brutally honest, I'd prefer to reject the kind of person who considers such a simple question to be too difficult or annoying to answer.
Image bases CAPTCHAs bring up a variety of issues, such as accessibly for people who are blind (and in many cases people who aren't blind). When bots are solving captcha more effectively then humans are, we have some major issues here.
That's one of my major beefs with CAPTCHAs which use increasingly hard-to-read text. It's getting so a person who's mildly colour-blind is going to have much more trouble with certain CAPTCHAs than a bot will.

Re: CAPTCHA vs skill-testing question

Posted: Sun Nov 01, 2009 9:07 pm
by Darth Wong
Roberdin wrote:Anyone who is not particularly numerically-orientated will not be interested in attempting to solve that problem.
My forum happens to be focused on science fiction and science-related issues such as evolution science versus creation BS, so I'd honestly prefer to avoid the kind of person who can't figure out time from distance and speed.

I have to be honest here: the phrase "not particularly numerically orientated" is a pretty generous way of describing someone who's basically too stupid to pass grade 9 math.

Re: CAPTCHA vs skill-testing question

Posted: Sat Nov 14, 2009 5:43 am
by Arrnea
I'm in favor of simple mathematical problems, written in words, as a replacement for CAPTCHAs, because some of the designs for the CAPTCHAs are quite difficult to read even with perfect eyesight.

Something like:
"Jack has six apples. Jack then gives three of those six apples to Paul. How many apples does Jack have left?"

Re: CAPTCHA vs skill-testing question

Posted: Sat Nov 14, 2009 3:58 pm
by stevemaury
IX + L = ? WolframAlpha can't answer that one.

Re: CAPTCHA vs skill-testing question

Posted: Sat Nov 14, 2009 8:03 pm
by stickerboy
Arrnea wrote:I'm in favor of simple mathematical problems, written in words, as a replacement for CAPTCHAs, because some of the designs for the CAPTCHAs are quite difficult to read even with perfect eyesight.

Something like:
"Jack has six apples. Jack then gives three of those six apples to Paul. How many apples does Jack have left?"
http://www.wolframalpha.com/input/?i=Ja ... ve+left%3F
stevemaury wrote:IX + L = ? WolframAlpha can't answer that one.
Indeed, but it would be interesting to see how long before it does start calculating Roman numerals :P

Re: CAPTCHA vs skill-testing question

Posted: Sat Nov 14, 2009 10:19 pm
by ToonArmy
cherokee red wrote:
stevemaury wrote:IX + L = ? WolframAlpha can't answer that one.
Indeed, but it would be interesting to see how long before it does start calculating Roman numerals :P
The problem is the 'L', it assumes it's a variable. IX + LX

Re: CAPTCHA vs skill-testing question

Posted: Sun Nov 15, 2009 3:47 am
by Noxwizard
You can feed it into Google first and then into WolframAlpha and you'll get the answer.