Random image text generation?

[Ben Finney]

Leif K-Brooks <eurleif at ecritters.biz> writes:

> Steven D'Aprano wrote:
> > For a text only solution, consider putting up a natural language
> > question such as:
> > 
> > What is the third letter of 'national'?
> > What is four plus two?
> > How many eggs in a dozen?
> > Fill in the blank: Mary had a little ____ its fleece was white as snow.
> > Cat, Dog, Apple, Bird. One of those words is a fruit. Which one?
>
> That wouldn't work as a true CAPTCHA (Completely Automated *Public*
> Turing test to tell Computers and Humans Apart), since making the
> list of questions and answers public would defeat its purpose.

The "Public" part of a CAPTCHA is the algorithm. The data consumed and
produced by the algorithm don't need to be publicly correlated -- and
indeed shouldn't be, for exactly the reason you state.

-- 
 \        "To me, boxing is like a ballet, except there's no music, no |
  `\    choreography, and the dancers hit each other."  -- Jack Handey |
_o__)                                                                  |
Ben Finney