What is CAPTCHA? How does it work and why does the text ‘I am not a Robot’ or selecting pictures appear on the website. Know the complete information behind this in simple language.
CAPTCHA Explained: If you have ever logged in to a website, created an account or filled out an online form, you must have seen the I’m Not a Robot box or the picture select test. It is called CAPTCHA. The full name of CAPTCHA is Completely Automated Public Turing test to tell Computers and Humans Apart. This means a test that helps tell whether the website user is a human or a computer program (bot).
Why does CAPTCHA come?
1. To stop the bot
There are many such automatic programs on the Internet, which are called bots. They can fill thousands of forms in a matter of seconds, create fake accounts or send spam on the website. The main job of CAPTCHA is to stop such bots. For example, if there is no CAPTCHA on a ticket booking website, then the bot can buy thousands of tickets instantly. Due to this, needy customers will not be able to get tickets.
2. To avoid creating a fake account
Social media, email and banking websites require a human being to create their account. If there is no CAPTCHA, the bot can create millions of fake accounts, which will increase spam and cyber crimes.
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3. To protect the website from cyber attacks
In some cyber attacks, the bot repeatedly tries to login or ask for the password. This is called Brute Force Attack. CAPTCHA helps slow down and in many cases stop such attacks.
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4. To reduce spam
Bots can send thousands of useless messages in comment sections, contact forms and online surveys. CAPTCHA ensures that the person filling the form is the correct user.
5. Why doesn’t CAPTCHA come every time?
Nowadays websites are no longer dependent only on CAPTCHA. They analyze many signals, such as browsing activities, mouse movements, clicking patterns, IP addresses, device information. If everything seems normal to the website, sometimes the CAPTCHA is not visible. But if the activities seem unusual, such as sending many requests too quickly or using a VPN/proxy, then the CAPTCHA appears.
Does CAPTCHA always ask to recognize images?
No. CAPTCHA has changed. Today many types of CAPTCHAs are used, such as I’m Not a Robot checkbox, selecting pictures like traffic light, bus or bicycle, typing letters or numbers, invisible CAPTCHA, which estimates the risk in the background.
Some interesting information about CAPTCHA
The term CAPTCHA came into discussion in 2003. It was developed by computer scientists Luis von Ahn, Manuel Blum, Nicholas Hopper and John Langford. Google’s reCAPTCHA was also used to train machines. In the old reCAPTCHA, the words read by the user were also used to digitize the scanned text of books and newspapers. The latest CAPTCHA does not depend only on clicks. Many systems also analyze the behavior of the user and decide whether he is a human or a bot. Millions of CAPTCHAs are used every day. CAPTCHA is used millions of times every day on websites in the world. CAPTCHA provides security, but it alone cannot do everything. Today websites use Two-Factor Authentication (2FA), AI-based bot detection, and other security features along with CAPTCHA.
Content Sources: Google (reCAPTCHA), Cloudflare, Carnegie Mellon University (CAPTCHA research), National Institute of Standards and Technology, OWASP Foundation