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Captchas without server state
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A view to generate a captcha image and/or wav file, and to verify user input
against it.
A cookie is used to transfer state from one request to the next. The state is
used, together with a server-side secret, to create a random string of
characters, which in turn is displayed as a captcha image, or transformed to
an audio file. Verification happens case-insensitively.
Note that the captcha 'word' is only usable for 5-10 minutes, after which the
view will not accept it any more. Moreover, a different word will be generated
for a given ...