This form of CAPTCHA requires entering a sequence of letters or numbers in a distorted image. It is a contrived acronym for 'Completely Automated Public Turing test to tell Computers and Humans Apart.' A historically common type of CAPTCHA (displayed as Version 1.0 ) was first invented in 1997 by two groups working in parallel. The term was coined in 2003 by Luis von Ahn, Manuel Blum, Nicholas J. tʃ ə/ KAP-chə) is a type of challenge–response test used in computing to determine whether the user is human in order to deter bot attacks and spam. This CAPTCHA (Version 1 ) of 'smwm' obscures its message from computer interpretation by twisting the letters and adding a slight background color gradient.Ī CAPTCHA ( / ˈ k æ p.
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