What is a Captcha & How is Captcha Useful?
Captcha is an abbreviation (full form) for Completely Automated Public Turing Test to tell Computers and Humans Apart.
Example of a Captcha image:
You might have visited lot of sites on the web world and you might have noticed that few sites are asking you to enter the words shown in an image (as like the above one) in the given field. You might have wondered why should u do it?
It is because of the reason that this kind of checking will be helpful in differentiating computer bots and humans. Still theres’ confusion? then read the following:
Letters (or words or characters or numbers or symbols) seen in this kind of images (captcha images) can only be read by humans. This kind of image can’t be read by computers or automated software tools or other such things. So, only humans can enter the information provided on this image in to the given field.
Why to differentiate bots and humans?
When we sign up for an email account or any other service on the web, we will be seeing such kind of captcha images at the end of the form. With this kind of form, administrators (of that webpage or website) ensure that the form is filled only by humans, and not by the automated systems.
If this kind of checking by CAPTCHA images is not present, any automated robots and software tools can also come to the page and can fill up the form and can generate an account with the service.
If this kind of Captcha checking is not present, the services offered on the web may be utilized for unauthorized ways and in undesired ways.
Few people (hackers and such people) try to create multiple accounts with a service so as to get more benefits from the service (in illegitimate ways) or hack the page or enter the admin area of the service.
Also, few other people try to fill up multiple forms and to maximize their benefit from the site (in undesirable ways), eating up the resources of the web service. This will become a huge loss to that web service and after some time, their entire list of subscribers will be filled with such kind of spammers.
In any given case, such kind of spammers will not be useful to the websites and moreover it will be a huge loss. This will directly effect the efficiency of the websites in offering their services.
Hence, websites will try to differentiate automated tools and human beings and prevent automated bots to fill up the form.
Now that you have understood why to differentiate automated tools and human beings, we shall now understand what are these automated tools.
What are spammers or automated bots?
There will be some tools (unwanted tools) used by hackers and spammers, and these tools will automatically open up a page (on which forms are present) and will fill up the form with random information or given information and will create accounts or subscriptions with that web page.
These kinds of automated bots will be useful for the hackers and spammers and will be a loss for the webpages (offering services).
Why these Captcha images are not readable by the bots?
Captcha images contain letters and words or symbols or characters, etc, but they will not be in alignment or they will be blurred. So, computer automated programs cannot read them. Only humans can read and understand them.
Normal text can be understood by the automated bots but Captcha image texts are not understood by these bots. Hence, they are used for differentiating human beings from bots.
We shall understand the implementation and usefulness of captcha in our next articles.
Thank you and keep reading other articles.