module providing CAPTCHA support in CGI::Application

 CGI::Application::Plugin::CAPTCHA allows programmers to easily add and
 verify CAPTCHAs in their CGI::Application-derived web applications.
 A CAPTCHA (or Completely Automated Public Turing Test to Tell Computers
 and Humans Apart) is an image with a random string of characters. A user
 must successfully enter the random string in order to submit a form. This
 is a simple (yet annoying) procedure for humans to complete, but one that is
 significantly more difficult for a form-stuffing script to complete without
 having to integrate some sort of OCR.
 .
 CAPTCHAs are not a perfect solution. Any skilled, diligent cracker will
 eventually be able to bypass a CAPTCHA, but it should be able to shut down
 your average script-kiddie.
 .
 When a CAPTCHA is created with this module, raw image data is transmitted
 from your web application to the client browser. A cookie containing a
 checksum is also transmitted with the image. When the client submits their
 form for processing (along with their verification of the random string),
 captcha_verify() generates a checksum of the verification string the user
 entered. If the newly generated checksum matches the checksum found in the
 cookie, the CAPTCHA is assumed to have been successfully entered, and the
 user is allowed to continue processing their form.