Sometimes when you try to sign up on any website, it asks you to enter some meaningless alphabets or alpha-numeric words presented in jumbled manner, this thing is known as captcha. Captcha was introduced in 2000 in order to differentiate between human and robots, so to prevent the hacking and virus attacks on websites. It was used by each and every website in registration forms but it eventually turns out to be a dubious procedure to follow every time during sign-up and its reliability is also not up to the mark. So, recently google came up with more reliable ans easy alternative called reCAPTCHA, based on images.
Captcha
Completely Automated Public Turing test to tell Computers and Humans Apart. A CAPTCHA is a type of challenge-response test used in computing to determine whether or not the user is human.
The term was coined in 2000 by Luis von Ahn, Manuel Blum, Nicholas J. Hopper of Carnegie Mellon University and John Langford of IBM. The most common type of CAPTCHA was first invented by Mark D. Lillibridge, Martin Abadi, Krishna Bharat and Andrei Z. Broder. 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. This term is ambiguous because it could also mean a Turing test in which the participants are both attempting to prove they are the computer.
The term was coined in 2000 by Luis von Ahn, Manuel Blum, Nicholas J. Hopper of Carnegie Mellon University and John Langford of IBM. The most common type of CAPTCHA was first invented by Mark D. Lillibridge, Martin Abadi, Krishna Bharat and Andrei Z. Broder. 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. This term is ambiguous because it could also mean a Turing test in which the participants are both attempting to prove they are the computer.
How it started
This program was started back in 2000 by Carnegie Mellon University of America. This was intended to help protecting internet from virus and hacking. The main function of captcha is to identify between real human user and robot because it was believed that robots cannot write captcha.
Limitations of Captcha
- In 2011, some computer scientists successfully made the program named De-captcha, that could read the captcha with 80% success. So, captcha technique was not that much secure as it was intended to be.
- In 2012, in a survey, 90% people said it was problematic to use captcha.
- In 2013, Google itself realised that captcha is not much reliable so they took first step towards the new technique reCAPTCHA.
reCaptcha
reCAPTCHA is a user-dialogue system originally developed by Luis von Ahn, Ben Maurer, Colin McMillen, David Abraham and Manuel Blum at Carnegie Mellon University's main Pittsburgh campus, and acquired by Google in September 2009. Like the CAPTCHA interface, reCAPTCHA asks users to enter words seen in distorted text images onscreen. By presenting two words it both protects websites from bots attempting to access restricted areas and helps digitize the text of books.
reCAPTCHA is a free service to protect your website from spam and abuse. reCAPTCHA uses an advanced risk analysis engine and adaptive CAPTCHAs to keep automated software from engaging in abusive activities on your site. It does this while letting your valid users pass through with ease.
reCAPTCHA offers more than just spam protection. Every time our CAPTCHAs are solved, that human effort helps digitize text, annotate images, and build machine learning datasets. This in turn helps preserve books, improve maps, and solve hard AI problems.
reCAPTCHA offers more than just spam protection. Every time our CAPTCHAs are solved, that human effort helps digitize text, annotate images, and build machine learning datasets. This in turn helps preserve books, improve maps, and solve hard AI problems.
Difference between Captcha and reCAPTCHA
Captcha was based on jumbled words [alphabets] whereas reCAPTCHA is based on images, where one question is asked whether user is robot or not ? Here, user can just tick mark the column and move ahead safely. This is more secure and easy technique to differentiate between human and robot.
No comments:
Post a Comment