How does CAPTCHA work?

CAPTCHA ! CAPTCHA ! CAPTCHA ! Before reading this article, you have to prove that you are not robot. HAHA ! I was just kidding friend. In my blog, everyone are welcomed by heart. But I am sure that you have seen such question or text scattered in internet, asking to prove that you are robot or not. If you have wonder that what is it and why it is done, then you are in right place. Here you will get all answers. For that please read this article till the end. Let us start. Have a great read.

What is CAPTCHA?

Whenever we have to fill a form online for anything or signing up any account or booking online tickets, we are usually asked to pass a test. That test is of different types. It can be to rewrite a puzzled text or twisted bend letters or recognizing particular pictures. Those test are called CAPTCHA. CAPTCHA stands for Completely Automated Public Turing Test to tell Computers and Humans Apart and It means that it is a test with the help of which computer or system can recognize that the user is a robot or a human.

Difficulty levels of this test for humans and robot

For talking about the difficulty level of this test then let me tell you that this test is not for troubling the human. It is just to distinguish robot and human. This test is well designed in such a way that it is easy for humans but difficult for robot. So according to research and its design, success rate are given below:
1. As this test is very easy for humans so the success rate that come out is

    Success Rate For Humans > 80%

2. And as mentioned before, it is well designed to restrict robots so it is very difficult for robot to pass such test and the success rate that come out is

Success Rate For Robots<0.01%

But you have been wondering that why such test are done. So don't worry let us know it now below.

Purpose of using CAPTCHA.

Talking about this topic that why many website and forms use this test then don't worry I will tell you here. It is a challenge response test that distinguish robot and human to restrict robot for any further action. It is used to stop all hacking and spams in internet. For example when we have to book a instant ticket for railway on time, we fill all the data but it take some time within which someone else can take away your sit using a script or bot. Bot are script that are program which can do task in just couple of min or second in computer. Many hacker and spammer also use such bot to create thousand of thousand email accounts. So to stop such spam and hacking, CAPTCHA was invented.

Evolution of CAPTCHA.

This test was invented in the year 1997 to restrict all those bot to prevent all spams. This early designed captcha was based on the ability of solving of distorted words that are easy for humans but difficult for robots.

 But some of those distortion of words were making trouble even for some humans so many other ways were used to make easy for humans and difficult for robots.

In this way, in the year 2008, Luis Von Ahn, who is the founder of Duolingo, redesigned the captcha and named it re-CAPTCHA. But in the year 2009, Google bought this re-captcha company for some improvement because they also wanted to stop spam. Google well designed it and came with a concept called The Invisible Captcha.

re-Captcha ( The Invisible Captcha)

In this invisible captcha, user are just asked to click on a box for a green check mark and test is done. But as mentioned in name, test is done invisibly. Here when you click on that box, you indirectly all google to check your IP address, location and most importantly your mouse curser movement just before click that box. By checking your curser movement, they detect that is it done by human or a robot. As the curser movement by robot are perfectly straight but by human it is little zig zag. In this way in this re-captcha, they process all the test in background by saving our time.

Also Read. How does Internet work

Conclusion

So, this all was about captcha, its purpose, working and evolution. I tied my best to cover all aspect in short. I hope you liked this article and it was helpful for you. If you have any further queries then you can ask me in comment section below. I will definitely answer them.
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