CAPTCHAs or “Completely Automated Public Turing tests to tell Computers and Humans apart” are a type of computerized Turing test to determine whether a user is a human or not.
CAPTCHAs usually consist of a distorted image of a word and a textbox to answer what that word is, but CAPTCHAs could also be math problems, 3D images, image identification and more.
Despite misconceptions, reCAPTCHA, a variation of CAPTCHA that was created by Luis von Ahn and later acquired by Google, is just one of many deployments of CAPTCHA technology.
