CAPTCHA

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en.wikipedia.org

CAPTCHA - Wikipedia

A CAPTCHA (/ ˈkæp.tʃə / KAP-chə) is a type of challenge–response Turing test used in computing to determine whether the user is human in order to deter bot attacks and spam. [1] The term was coined in 2003 by Luis von...

developers.google.com

reCAPTCHA | Google for Developers

reCAPTCHA is a free service that protects your site from spam and abuse. It uses advanced risk analysis techniques to tell humans and bots apart. reCAPTCHA v3 helps you detect abusive traffic...

www.cloudflare.com

How CAPTCHAs work | What does CAPTCHA mean? - Cloudflare

What is a CAPTCHA? A CAPTCHA test is designed to determine if an online user is really a human and not a bot. CAPTCHA is an acronym that stands for "Completely Automated Public Turing test to tell Computers and Humans...

www.captcha.net

The Official CAPTCHA Site

CAPTCHA: Telling Humans and Computers Apart Automatically A CAPTCHA is a program that protects websites against bots by generating and grading tests that humans can pass but current computer programs cannot.

www.ibm.com

What is CAPTCHA? - IBM

CAPTCHA stands for "completely automated public Turing test* to tell computers and humans apart." It refers to various authentication methods that validate users as humans, not bots, by presenting a challenge that is ...

securityboulevard.com

CAPTCHAs 101: what they are, how they work, and where they ...

Jul 1, 2025 · CAPTCHA stands for Completely Automated Public Turing test to tell Computers and Humans Apart. As the name suggests, it’s a challenge designed to separate human users from bots. The original idea was str...