The full form of CAPTCHA is Completely Automated Public Turing test to tell Computers and Humans Apart. That is, a test that a human can solve in a jiffy, but it is a big challenge for the world’s most powerful supercomputers and AI algorithms to understand it.
Why is captcha necessary?
There are millions of automated programs (Bots) active on the Internet, which try to spread spam, create fake accounts, buy tickets or sale items in seconds, and crack passwords. Captcha works to stop these bots. For example, online ticket booking, deeply discounted e-commerce sales, website comment section and login and password pages. Captcha is applied at these places so that real users get priority and not machines.
How does captcha prevent hacking and spam?
Hackers try millions of password combinations through bots. CAPTCHA forces bots to stop frequently because they cannot solve the puzzles. This keeps the account safe.
Where did it start?
The history of CAPTCHA starts from the late 90s. It was first used by AltaVista in 1997, but it was officially recognized and named in 2003 by Louis von Ahn and his team at Carnegie Mellon University. Lewis later created Re-CAPTCHA, which used to show those words from old newspapers that computers could not scan. When millions of people solved it, they were unknowingly helping in digitizing old books. Google understood its power and bought it in 2009. After this Google used it for two big purposes.
Google Books: The work of digitizing millions of old books gained momentum.
Google Maps: You must have noticed that after some time, house numbers and road sign boards started appearing in the captcha. Actually, Google was making you read house numbers and sign boards for its Street View maps so that the maps could be more accurate. Then as AI advanced, bots also started reading distorted words. Then Google introduced the I’m not a robot checkbox. It doesn’t just see a click, it also tracks your mouse movement, browser history, and cookies before you click. The human mouse moves in a slightly chaotic manner, while the bot clicks in a straight line or jerkily. From this one can understand the difference between man and machine.
How does Google take work from you for free?
Not only this, when you recognize pictures of a bicycle, bus or car in the captcha, then you are unknowingly training Google’s AI system. This improves Google’s self-driving cars and image recognition technology. That means, along with security, you are also contributing to AI development.
