The easiest way to keep spam bots away. Secure your blogs, forums, comment boxes & directories so robots cannot crack their way inside. A captcha is a logical question test used on the internet to determine whether or not the user is human. Questions should be simple enough for anyone to answer. And also this class has innovation award at PhpClasses.org.

Author : Josh Storz
Quote :

“This class can be used to perform CAPTCHA validation presenting to the users simple mathematical expressions as a sequence of animated pictures to make it difficult for robots to pass a form being validated.

It generates an animated GIF image that displays a mathematical expression of a simple operation between two random numbers, like sum, subtraction and multiplication.

The numbers and the operation are stored in session variables for posterior verification. “

Demo

Detailed Class Information

Download PHP Captcha via the Animated Gif