Random image text generation?
skip at pobox.com
skip at pobox.com
Tue Nov 14 10:51:14 EST 2006
>>>>> "Paul" == Paul Rubin <"http://phr.cx"@NOSPAM.invalid> writes:
Paul> Steven D'Aprano <steve at REMOVE.THIS.cybersource.com.au> writes:
>> Instead of displaying an obfuscated image of a nonsense word, display
>> six randomly chosen photos, where five are of the same thing but not
>> the same image. E.g. you might show five different kittens and a
>> horse. The user has to click on the image that is not the same as the
>> others. State-of-the-art horse-recognition software is not yet in
>> widespread use by spammers *wink*
Paul> No need to recognize the horse. Just pick one of the pictures at
Paul> random and you'll get the right one 1/6th of the time. Repeat ad
Paul> infinitum--they're spammers and like to repeat stuff after all.
Paul> That's why those conventional captcha images make you recognize a
Paul> multi-character string: so the guessing chance is low.
Actually, the ones I saw that used a set of "one of these things is not like
the other" images gave you a pop-up menu of maybe 100-200 words. The user
needed to choose the name of the different object from that list. That
makes it a bit harded to guess. Of course, these sorts of tests suffer from
the same shortcoming as the randomly generated string. Visually impaired
people have trouble with it.
I finally settled on just reusing the SpamBayes engine to detect/reject spam
submissions.
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