PhpCaptcha is a PHP script for generating visual and audio CAPTCHAs, which can completely automated public turing test to tell computers and humans apart. It is created to prevent you from automated sign-ups in registration forms; to reduce comment spam in blogs and guestbooks; to protect you from brute force attacks on login system.

Features of PhpCaptcha - Visual and Audio PHP CAPTCHA Generation Script:
- Multiple random TrueType fonts
- Character rotation
- Optional chararacter shadow support
- Optional site owner display text
- Random custom background images
- Font size selection
- Greyscale or colour lines and characters
- Character set selection
- Integration of validation function for checking the user entered code with the generated code

Requirements:
- PHP 4.0 or Higher compiled with GD 1 or 2 (Image Generation) and FreeType text support
- Linux, Mac OS X or Windows based systems although you will need to change the default temporary file storage directory specified when using with Windows.
- the Flite text to speech synthesis engine