CAPTCHA

QUESTION -  

A very common test  "Completely Automated Public Turing test to tell Computers and Humans Apart" to tell Computers and Human apart  is a type of challenge-response test used in computing to determine whether or not the user is human . What ?

ANSWER - 

' CAPTCHA '

The term was coined in 2003 by Luis von Ahn, Manuel Blum, Nicholas J. Hopper, and John Langford. The most common type of CAPTCHA was first invented in 1997 by two groups working in parallel: (1) Mark D. Lillibridge, Martin Abadi, Krishna Bharat, and Andrei Z. Broder; and (2) Reshef, Raanan and Solan. This form of CAPTCHA requires that the user type the letters of a distorted image, sometimes with the addition of an obscured sequence of letters or digits that appears on the screen. Because the test is administered by a computer, in contrast to the standard Turing test that is administered by a human, a CAPTCHA is sometimes described as a reverse Turing test.