Home ยป What is ReCAPTCHA and how does it work?

What is ReCAPTCHA and how does it work?

A lot of us have come across one of these when we try to either log in, sign up or perform an action on a website.

ReCAPTCHA being clicked on and verified.

It’s called ReCaptcha, and it is designed to stop bots. Bots are pieces of software designed to do one specific thing, they can be malicious or just pull data but this tool is designed to stop them. So you may be asking yourself “It’s just a box that we click (or tap) on, how does that prevent a bot?” and well the answer is quite simple. It analyzes the way you move your cursor before and after you hit the box, how did you hit it, what’s your IP Address, And other data that Google doesn’t want to reveal (To prevent people from creating a tool that bypasses it). It uses that data it collected, processes it and decides either to let you pass or to put you a challenge. A challenge is designed to be easy for humans but hard for bots, it consists of either answering a form with text and lines (or an audio ReCaptcha for the visually impaired), clicking boxes in which there are objects or identifying items. That is very hard for bots to solve, it looks something like this.

ReCAPTCHA challenge prompting the user to select all images of a sandwich.

Why RECaptcha?

That you get a challenge doesn’t necessarily mean that Google thinks you’re a bot it just means that it needs a little more confirmation, ReCaptcha is open to any website owner that decides to get an API key, it is completely free, there are different kinds of ReCaptcha, the invisible ReCaptcha which you mostly don’t ever see unless you fail it and the normal one. It is called ReCaptcha since it is a much newer, advanced, and more intelligent system that the previous CAPTCHA which looked like this and you forcedly had to complete a challenge.

Old CAPTCHA prompting a user to write down “Levelers Critics” in a box.

There are services out there that complete captcha for you either for personal use or for a bot. These are completely against Google’s ToS and consist of a farm of people solving ReCAPTCHAs and being sent to them.
If you are wondering why CAPTCHA, well it is actually an acronym and it stands for:

C Completely
A Automated
P Public
T Turing Test
C Computers
H Humans
A Apart

No, I am not joking this is the actual acronym, the software industry is just really bad at acronyms.

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