Minteye offers no-type CAPTCHA as a security twist

(—Minteye is offering a no-type option to annoying CAPTCHA tests where users' first tries turn into third and fourth tries to get the blurry, blotched letters and digits correct for entry. The company Minteye, ...

Stanford research team cracks animated NuCaptcha

( -- The research team from Stanford University, led by Elie Bursztein, that previously had cracked regular CAPTCHAs and then audio CAPTCHAs, now has also successfully cracked the animated version called NuCaptcha. ...

Stanford researchers outsmart captcha codes

( -- Stanford researchers say that captcha security codes, asking Internet sign-up users to repeat a string of letters to prove the users are human, can be thwarted, and they have successfully defeated captcha ...

Stanford computer scientists find Internet security flaw

( -- Researchers at the Stanford Security Laboratory create a computer program to defeat audio captchas on website account registration forms, revealing a design flaw that leaves them vulnerable to automated attacks.

Strong protection for weak passwords

( -- The combination of simple codes and Captchas, which are even more encrypted using a chaotic process, produces effective password protection.

Moving video to 'captcha' robot hackers

We see the popular "captcha" security mechanism often ― wavy letters websites ask us to type into a box. It's used by web pages and newsletter sign-up forms to prevent computer robots from hacking into servers and databases. ...

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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