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alternative to captcha image?
Posted: Mon Jan 26, 2009 5:54 pm
by yacahuma
I was thinking that an alternative could be something like this
Story:
Mary like to travel to spain
Possible questions:
Who likes to go to Spain?
What does mary like to do?
Where does Mary likes to go?
Could this be a good captcha alternative? Why Not?
It is easier to break a captcha images, than to understand a story?
Re: alternative to captcha image?
Posted: Mon Jan 26, 2009 7:18 pm
by JellyFish
May be true. But where are you going to get these stories? There will have to be many, and your server will need a way to understand them.
But Idk.
Re: alternative to captcha image?
Posted: Mon Jan 26, 2009 8:15 pm
by yacahuma
My server does not have to understand it. I am going to have the question and the answer. So they are not going to be dynamically generated.
But know that you mention, there could be a way to automatically generate it.
I guess all I have to do is give it a bunch of names , actions, subjects, and the the random generator will pick what will be the answer(it is the subject, is it the verb,etc)
It was simpler when I thought I will put the stories and the questions. I think is possible and you could write a bunch of them in a very short time.
Re: alternative to captcha image?
Posted: Mon Jan 26, 2009 8:28 pm
by Chris Corbyn
I think these sorts of captcha can work well given enough variation.
Another example could be a 4x4 grid with letters on the X axis and numbers on the Y axis. Inside each square would be a picture of an every day object (like an Apple, a Pencil, a Car etc..).
Then you ask the user "Which square is the Apple in?".
You can randomise these tests easily too, and you can distort the images slightly so that a simple hash algorithm on the images won't work.
Re: alternative to captcha image?
Posted: Mon Jan 26, 2009 8:30 pm
by Chris Corbyn
Even better, in my example above, for the sake of simplicity (so the user doesn't have to look up coordinates), ask the user "Click on the apple".
Re: alternative to captcha image?
Posted: Mon Jan 26, 2009 11:32 pm
by daedalus__
you know i've recently heard of people making puzzles out of captcha. i think its a wonderful idea.
Re: alternative to captcha image?
Posted: Mon Jan 26, 2009 11:40 pm
by Chris Corbyn
You just have to be careful not to:
a) Make it inaccessible to people with disabilities
b) Make it too hard for stupid people to get past (and there are a lot of stupid people on the interwebs

)
Really, I guess my idea that uses images is not accessible to visually impaired users.
Re: alternative to captcha image?
Posted: Tue Jan 27, 2009 10:26 am
by josh
yacahuma wrote:
Could this be a good captcha alternative? Why Not?
It is easier to break a captcha images, than to understand a story?
No, but since its less commonly used people would be less motivated to break it. Overall OCR is more difficult than this. Once they identify the subject and predicate of the phrase, and the questions, it becomes fairly easy to guess the meanings with a good database of synonyms / related terms
Chris Corbyn wrote:Another example could be a 4x4 grid with letters on the X axis and numbers on the Y axis. Inside each square would be a picture of an every day object (like an Apple, a Pencil, a Car etc..).
Then you ask the user "Which square is the Apple in?".
Again even easier to crack, if you ignore the fact if you were the only one doing this noone would bother cracking it unless you were "big time".
If you want a question a human can answer but is difficult for a machine it should be things like "which day of the week does the ground become alive and bite you?" and have for instance "trick question" among the possible values. Stuff that requires too obscure knowledge that wouldn't be easy to compile a database on. Although if you create these manually its going to take you longer to create than it would for the person to crack, something that is definitely not true for captchas ( which work fine IMO ).
Re: alternative to captcha image?
Posted: Wed Jan 28, 2009 11:23 pm
by clickbuild
I recently moved to using a random challenge type for each page load.
First one is a color challenge, next is captcha, next is story, next is ...
Someone needs to do a ton of programming to cover the different types of challenge AND the different answers - only worth it is there is a pot of gold at the other end
--
Steve
Re: alternative to captcha image?
Posted: Sun Feb 01, 2009 2:23 am
by LonelyProgrammer
I used a "answer the math questions" to filter out spam-bots, and realise that I have to watch out for language barriers. I used variants of "what is 1 plus 1" and "what is 1 add to 1" and it trips up a lot of people.
Do those measures work anyway? I thought a spam-bot could just look at the values in the cookie to determine which puzzle is being used and then matched it to response (your form elements, after all, will have some hard-coded values).
Re: alternative to captcha image?
Posted: Sun Feb 01, 2009 11:22 am
by josh
Scanning a limited mathematical vocabulary into its syntactic units and calculating the answer would be far easier than implementing OCR
Re: alternative to captcha image?
Posted: Mon Feb 02, 2009 12:57 pm
by JAB Creations
I've been spam free for years now, why? Bots are dumb. I mean dumb.
Captcha is for people who think bots are smart.
What does a bot need to succeed? A form.
What will a bot do that a human won't?
What if you don't give the form to a bot?
What if you think about all the things bots don't do that humans do?
I mean seriously, bots are dumb.
"Sometimes questions are more important than answers." - Nancy Willard
Re: alternative to captcha image?
Posted: Mon Feb 02, 2009 10:11 pm
by josh
?
Re: alternative to captcha image?
Posted: Mon Feb 02, 2009 10:13 pm
by Benjamin
JAB Creations wrote:I mean seriously, bots are dumb.
One could argue that forms processing post data are dumb as well, but it's still not a valid argument, because dumb is
ambiguous.
Re: alternative to captcha image?
Posted: Tue Feb 03, 2009 5:30 pm
by josh
And yeah bots can make inferences far further than humans. For instance in my AI book one of the examples they give is an algorithm that given the following facts, can answer the question "where does the zebra live, and in which house do they drink water":
the englishman lives in the red house
the spaniard owns the dog
the norwegian lives in the first house on the left
kools are smoked in the yellow house
the man who smokes chesterfields lives in the house next to the man with the fox
the norwegian lives next to the blue house.
the winston smoker owns snails
the lucky strike smoker drinks orange juice
the ukrainian drinks tea
the japaneese smokes parliments
kools are smoked in the house next to the house where the horse is kept
coffe is drunk in the green house
the green house is immediatly to the right ( your right ) of the ivory house.
milk is drunk in the middle house.
All this would be is an elementary academic exercise in AI, and would block out 99% of the humans I know.