What is CAPTCHA?
CAPTCHA is a test to determine if the user using the system (usually a web form) is a human. It identifies this by throwing challenges to users. Depending on the responses the identification can be made. E,g Answering to identification of distorted images. Captcha Creator is a PHP Script that generates Strong Captchas
What is CAPTCHA in PHP?
Captcha are images with some characters/ digits on it. One need to type the characters or digits in the text box for the purpose of submitting. This avoids automatic submitting by an operation by other programs or a robot.