Perl program which can be used in cgi forms to present a random "challenge/response" jpeg for use in preventing mass/automated form submissions. Several sites such as Yahoo and Paypal have a similar feature on their sign-up pages but there does not appear to be any plug-in code available for a non-programming webmaster to add something similar to their own sites. It will be able to use Imagemagick, GD or netpbm graphics libraries in order to work on the greatest number of systems.
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