The
term "CAPTCHA" means "Completely
Automated Public Turing test to tell Computers
and Humans Apart". A CAPTCHA is a type of challenge-response
test used in computing to ensure that the response is not generated by a
computer. It is a simple verification test which the computer is able to
generate and grade. Because other computers are unable to solve the CAPTCHA,
any user entering a correct solution is presumed to be human. A common type of
CAPTCHA requires that the user type the letters or digits of a distorted image
that appears on the screen. CAPTCHAs are used to prevent automated software
from performing actions which degrade the quality of service of a given system.
Developers will try to come up with new and better tests, and
spammers will continue to find ways of cracking them; it's very much a vicious
circle. Perhaps, at some point in the future, somebody will come up with a test
that is truly reliable and an uncrackable -- something that identifies humans
in a way that cannot be faked.
- What is CAPTCHA?
A CAPTCHA is a type of challenge-response test used in
computing to ensure that the response is
not generated by a computer. The process usually involves one computer
a serve asking
a user to complete a simple test which the computer
is able to generate and grade. Because other computers are
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 to a human, in contrast to the standard
Turing test that is typically administered by a human and targeted to a
machine. A common type of CAPTCHA requires that the user type letters or digits
from a distorted image that appears on the screen.
CAPTCHA (initiated by researchers at Carnegie Mellon University and IBM
in 2000) works by understanding the OCR methods and displaying text that can
break them. Of course this a game two can play, so OCR designers can modify
their methods to read the distorted text.
While CAPTCHAs started with text they have started using other images
that maybe easy for a human to recognize but they baffle computers. Also, some
of the new tests are not public so the technology is now called HIP that stands
for
Human
Interaction
Proof.
Human
Interaction
Proof.
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