What is CAPTCHA?
CAPTCHA is a contraction for “Completely Automated Public Turing test to tell Computers and Humans Apart”. It is basically a kind of test (challenge-response) utilized in computing in order to determine if the user is a human being or not.
The term CAPTCHA was originally introduced in 2003 by John Langford, Manuel Blum and Luis von Ahn. The CAPTCHA form actually requires the user to type the letters which are displayed in an image which is very much distorted. Since it is a computer based test hence CAPTCHA is also sometimes referred to as reverse Turing test.
CAPTCHA has also been criticized by many. The disabled people usually hold a very negative view pertaining to it. Similarly many ordinary people also criticize CAPTCHA based on the premise that it really slows down the daily tasks. 10 seconds is the average time which a person takes in order to solve CAPTCHA.
Characteristics of CAPTCHA
The processes involved in CAPTCHA are highly automated and in majority of the cases there is no need for human maintenance etc. The overall benefits of CAPTCHA are more linked with its reliability as well as cost.
The algorithms which are utilized for the development of CAPTCHA have been made public however these algorithms are secured by Patent. The modern day CAPTCHAs are text based and have been designed in such a way that they are in need of using three different abilities namely parsing, invariant recognition and segmentation. These abilities are used to finish the task with any kind of consistency.
- The potential to recognize a lot of variation in the shapes of different letters is known as Invariant recognition.
- The ability or potential to separate one particular letter from the other is called segmentation. The segmentation is made very difficult in the CAPTCHA, the characters are held together with no significant space in between.
- Context is also something which is highly critical. One must understand CAPTCHA holistically so that the characters can be identified correctly.
Is Captcha Really Needed on the forms?
The best way to stop spambots from entering your webpage is CAPTCHA. This is one of the strongest arguments which proponents CAPTCHA place. On the other hand the people who are against CAPTCHA come up with this argument that it is something which is annoying and really disrupts the process within which a person is currently in.
The best way to determine the importance of CAPTCHA is by testing it on the form by yourself. It is better that you test the, from in absence of CAPTCHA first to see the real difference.
CAPTCHA and RECAPTCHA
Both RECAPTCHA as well as CAPTCHA have the same purpose. The RECAPTCHA was introduced to get the newspapers, old books and addresses digitalized. Its basic purpose is to transform the words that cannot be crawled by computers into CAPTCHAs for human beings to solve.
A Drawing CAPTCHA is also very much their which allows the utilizers to trace the images that have been randomly selected rather than typing in the box. If the drawing is done with a little bit of accuracy then the system will not take you as a bot. This may take more time as compared to traditional CAPTCHA however this is something interesting.