what is captcha

[divorceclass]

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

[markellis312]

Captacha just like a Verification code.

[paulbrighton]

Captcha is a program or system intended to distinguish human from machine input.

[robertmiker]

CAPTCHA is to ask for human verification.

[netxsolution]

Captcha is the best thing , actually captcha is the difficult wording mixture , which helps you save your website, software with any type of spamming and bulking. thanks

[DoloresPiper]

A captcha is a program which is used to distinguish human from machine. It is a way of catching the spammers and automated extraction of data from website.

[singhabhishek25]

I do not believe that there could be 322 reply for this simple question somewhere and this is 323rd, but obviously not an answer,but a concern for the spamming. I am wondering how many varieties of answer can be found here. I am going to read all of them one by one.

[christopher12]

captcha is the verification code for verificatio

[123johnsin]

verification code is called captcha.

[harry26]

captcha is need for any website for stop to automated spam or only authorize unique visitors to access any site.

[Bluesky94]

A CAPTCHA (a backronym for "Completely Automated Public Turing test to tell Computers and Humans Apart") is a type of challenge-response test used in computing to determine whether or not the user is human.
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.