Random image text generation?

[skip at pobox.com]

>>>>> "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.

Skip