How to exercise CAPTCHA with PHP as well as GD

So, we have the open acquiescence form upon your website (contact page, forum submission,blogs criticism form) as well as need to forestall spam by auto-submitters. Common approach to do this is to exercise CAPTCHA – an picture with incidentally generated string

(quote from Wikipedia, giveaway online enciclopedia: “A CAPTCHA is the sort of challenge-response exam used in computing to establish either the user is human. “CAPTCHA” is an acronym for “Completely Automated Public Turing exam to discuss it Computers as well as Humans Apart”, copyright by Carnegie Mellon University.”)

Simple as well as discerning PHP resolution for implemet CAPTCHA:

1) Make the PHP script that will beget the CAPTCHA image:

[?php

session_start();

header(”Expires: Mon, twenty-six July 1997 05:00:00 GMT”);

header(”Last-Modified: ” . gmdate(”D, d M Y H:i:s”) . ” GMT”);

header(”Cache-Control: no-store, no-cache, must-revalidate”);

header(”Cache-Control: post-check=0, pre-check=0″, false);

header(”Pragma: no-cache”);

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