What CAPTCHA stands for and why was it invented?

CAPTCHA, which is a collection of distorted letters and numbers, stands for Completely Automated Public Turing test to tell Computers and Humans Apart.

Mark D. Lillibridge, Martin Abadi, Krishna Bharat and Andrei Broder are credited with inventing a 'method' in 1997 to prevent web robots, popularly known as bots, from accessing their search engine. The term 'CAPTCHA', however, was later coined in 2000 by Luis von Ahn, Manuel Blum, Nicholas J. Hopper of Carnegie Mellon University, and John Langford of IBM. CAPTCHAs are present on a number of websites. It is used in computing to determine whether or not the user is human. They prevent bots from accessing sensitive information and also from sending spam e-mails. You can send your feedback on smementor@moneycontrol.com or simply post comments below