This is simple, complete and powerfull captcha tool written in PHP for protecting your web FORMS from spammers.Under GPL. A good solution for this is to use an random code that is generated by a script the code will be displayed as an image so only a person could read the image and type the number. "Captcha ZDR" offers several methods of captcha protection, different fonts, string protection, calculation protection (sum and deduction), noise in image, string symbols are hard for reading from spamer machines. * 8 unique backgronds for captcha image. * Easy to install in your web pages. * No DataBase required. * Hard Protection $_SESSION['captcha'] variable contain RIGHT result from CAPTCHA image. You can use example.php and example_submit.php for more information.