Captcha PHP is a program used to verify that a person, not a computer, enters data. CAPTCHAs are usually displayed at the end of online forms and ask the user to enter text with a distorted image. The text in the image can be masked by a distorted font, wave and zigzag lines, and the automatic recognition program cannot detect it. Some Captcha PHP include an audio pronunciation feature. Captcha tests can stop 90% of hacker attacks by blocking the robot software and restricting the sending of online requests.
Definition
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//google Captcha PHP PHP image Captcha
// Adapted for The Art of Web: www.the-art-of-web.com
// Please acknowledge use of this code by including this header.
?>
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Using Captcha as protection against cross-site request forgery is not recommended, as there are stronger countermeasures.