As the first security door, made captcha to prevent brutal action from a robot. How do I create one? Find out more here. Re-typing a line of random characters for reasons of security seems to be mandatory that you must do when making the registration process for membership online. Not only in the registration form online, similar things can be encountered during the process online transactions in which the transmitted data is data that is crucial. Random character string that you need to reset the type is known by the term captcha. Captcha is made with the assumption that only men can see the whole picture and identify the characters shown for a reset. This is to prevent the brutal actions carried out auto-generated by script or robot system in disarray a website. Programmer website utilizing GD library in PHP script that converts them to create a line of random characters into an image. This article will discuss how to make a captcha system by using GD library functions. About PHP-GD