Photo Captcha with user defined images to reduce the spambot prize/payload to one website at a time. A captcha with "Which one of these things is not
Pictcha is a very unique & secure CAPTCHA.
Adds a CAPTCHA to account registration that uses Vidoop's ImageShield.
A script which protects the comment form from spam. Does four ways of protection.
Let admin create a page to do automatic exchange links with other webmaster
Security Captcha es un sistema para prevenir spam de cualquier tito, tanto por personas como por scripts creados por personas.
Allows you to display a captcha on your comment form to avoid spam.
Add a captcha to protect comments from being spammed using Cryptographp library.