CAPTCHA PHP, AJAX, JQUERY - EXAMPLES, RESOURCES, TUTORIALS
CAPTCHA is an automatic method to determine if the user software (Internet site, etc..) Is a person or a computer program. Method name stands English expression "Completely Automated Public Turing test to tell Computers and Humans Apart", the English word phonetically resembles the word CAPTCHA capture ("catching", "capture"). The name was chosen in 2000 by a group of researchers at Carnegie Mellon University and IBM. CAPTCHA is a special form of Turing test, administered automatically by a server (usually the Turing test is administered by a man).
Most common form of CAPTCHA is presented as an image containing distorted letters that the user must recognize and to reintroduce the keyboard, to prove that he is a person, not a program. Old versions of this test have already been defeated by advanced software optical character recognition. Part in these programs still remain behind the man is garbled text segmentation in individual letters, the difficulty of programming the modern versions are based CAPTCHA
EXAMPLES
http://www.captcha.fr/ FREE - Cryptographp PHP - 12 Tipes and pluguins for WordPress, Symphony, Guppy
12 different types of background, colors, fonts etc and some plugins for blogtipes sites.
http://www.phpcaptcha.org/ FREE - Free PHP CAPTCHA with refreshing and audio play tool
http://jcaptcha.sourceforge.net/ FREE - A couple of Free PHP CAPTCHA
http://www.captchacreator.com/ FREE - Three PHP CAPTCHA with refreshing
http://caca.zoy.org/wiki/PWNtcha/ FREE - PHP CAPTCHA decoder labs
http://demos.telerik.com/aspnet-ajax/captcha/examples/overview/defaultcs.aspx FREE - 4 .FREE ASP AJAX CAPTCHA
