A CAPTCHA (Completely Automated Public Turing to tell Computers from Humans Apart) is a program that can generate and grade tests that:

This script is the starting point of our PHP CAPTCHA Solver solution. It includes the OCR class and creates an object of that class. It uses the Learn function ...

This package implements CAPTCHA validation using math operation images. It can generate an image displaying a math operation between two numbers.

This class can be used to perform CAPTCHA validation, display text letters using ASCII art fonts. It generates a CAPTCHA validation text string with random ...

This class can be used to implement CAPTCHA validation using colored boxes that the user must click which are validated using AJAX requests.

ASCII Captcha. ascii-captcha.gif This package can perform CAPTCHA validation with multiple solutions. It can generate HTML to display several types of ...

This class can be used to create images from CAPTCHA validation. It can generate a random text with 5 characters from restricted range of characters which ...

This package can authenticate human users with audio CAPTCHA. It provides means to verify if the current user is a real human by outputting an audio sample ...

This class can generate an image for CAPTCHA validation. It can generate an image with a validation text made of random letters.