Security

Real-time Captcha technique improves biometric authentication

A new login authentication approach could improve the security of current biometric techniques that rely on video or images of users' faces. Known as Real-Time Captcha, the technique uses a unique "challenge" that's easy ...

Computer Sciences

Vicarious AI team reveals how it defeated CAPTCHA

A group of researchers at Vicarious AI has revealed for the first time the new and innovative method they used to defeat CAPTCHA. In their paper published in the journal Science, the team describes their neural network and ...

CAPTCHA

A CAPTCHA ( /ˈkæptʃə/) is a type of challenge-response test used in computing as an attempt to ensure that the response is generated by a person. The process usually involves one computer (a server) asking a user to complete a simple test which the computer is able to generate and grade. Because other computers are assumed to be unable to solve the CAPTCHA, any user entering a correct solution is presumed to be human. Thus, it is sometimes described as a reverse Turing test, because it is administered by a machine and targeted at a human, in contrast to the standard Turing test that is typically administered by a human and targeted at a machine. A common type of CAPTCHA requires the user to type letters or digits from a distorted image that appears on the screen.

The term "CAPTCHA" was coined in 2000 by Luis von Ahn, Manuel Blum, Nicholas J. Hopper, and John Langford (all of Carnegie Mellon University). It is an acronym based on the word "capture" and standing for "Completely Automated Public Turing test to tell Computers and Humans Apart". Carnegie Mellon University attempted to trademark the term, but the trademark application was abandoned on 21 April 2008.

Characteristics: A CAPTCHA is a means of automatically generating challenges which intends to:

A check box in a form that reads "check this box please" is the simplest (and perhaps least effective) form of a CAPTCHA. CAPTCHAs do not have to rely on difficult problems in artificial intelligence, although they can.

This text uses material from Wikipedia, licensed under CC BY-SA