2007
Math Comment Spam Protection Plugin
This plugin for Wordpress 1.5.2, 2.0.x and 2.3 asks the visitor making the comment to answer a simple math question. This is intended to prove that the visitor is a human being and not a spam robot.
Example of such question:

This plugin does not require JavaScript or cookies. It uses a special encryption function; the result of the question is being passed via a hidden field. The result is being compared with the value entered by the visitor – after encrypring this value as well.
Download the plugin here : Plugin Homepage

