CAPTCHA stands for Completely Automated Public Turing test to tell Computers & Humans Apart.
Originally, these tests used images that contained a combination of simple-yet-distorted alphabets & numbers.
So, while humans could read the text from the image, the bots couldn’t pick different characters from it, as the software had not evolved enough to break down imagesFor e.g., let’s say you have a picture of your car’s number plate that reads ABC 123; if you were to write this text on a piece of paper, you could do it, but if you tried searching (Ctrl+F) for ABC on this image, the computer will not show any results..
Eventually, however, the character recognition software evolved and it became easier for some programs (bots) to identify characters on the image.
In 2014, it was reported that computers got the CAPTCHA test right 99.8% of the time.
So, an advanced version in the form of the “I am not a robot” checkbox came to the scene, and it was named reCAPTCHA.
This technology had been acquired by Google in 2009 and, for obvious reasons, the full details on how it works have never been disclosed.
Tech experts, however, have developed an indicative list of how reCAPTCHA works.
First, it tracks the movement of the mouse, i.e. if the movement to the checkbox is ‘too smooth and quick’ or ‘too slow’, it is a red flag, and reCAPTCHA would give you a few images (crosswalks or traffic lights, etc.) to click, before letting you in.
Similarly, when you are asked to click on images containing traffic lights, you would usually stop for a few seconds before making the selection, unlike bots, who would do this in milliseconds.
So, it can be said that Google is more interested in how you interact with the page and may not care too much about your ability to find every slide containing a traffic light.
Google also takes into consideration your recent activity online.
So, if you misspelled a word in your search a few minutes ago, or if you had been clicking different links for some time finding a pair of shoes, the checks would be far less stringent.
In short, the more ‘less than perfect’ behaviour you exhibit, the easier your entry becomes.
So, it is not that robots can’t check the boxes, just that Google would figure out if it was a bot.
However, with fast-paced advancements in technology, this is seen as an ongoing race, and reCAPTCHA will have to keep evolving to remain ahead of the bots.
