Google has continuously been leading the way for better Completely Automated Public Turing test to tell Computers and Human Apart (CAPTCHA) services in order to deal with spambots and make it easier for humans to be granted access to products and services.
From the old and not-so-reliable CAPTCHA that once screened spambots and humans by generating random unreadable strings and photos, Google announced the "I'm not a robot" checkbox in December 2014. It then moved on to using themed photos to distinguish real persons from programs.
Google did not explain the details of how reCAPTCHA works but said the system combines advanced risk analysis and machine learning to screen out robots. Using what the machine learned over time, the company's reCAPTCHA team finally came up with an even better and stealthier solution, which it applies in the new application program interface (API).
Google's reCAPTCHA is now invisible and works in the background, which means humans no longer need to check a box or look at themed photo sets to continue browsing a site. The new system makes browsing seamless and more convenient, especially on mobile sites.
How It Works
reCAPTCHA is a completely free service that comes in the form of a widget and anyone can use it in their websites for as long as the user signs up for an API key pair.
The API key pair is composed of two parts: the site key and the secret, wherein the secret authorizes and facilitates the communication between the website and the reCAPTCHA server for verification purposes.
Unlike the previous version of reCAPTCHA, the invisible reCAPTCHA is directly invoked when a site visitor clicks an existing button so neither bots nor humans have any idea which section of the website is actually verifying whether they are human or not. It can also be invoked directly via a JavaScript API call.
According to Google, reCAPTCHA is programmed to only request further verification if the traffic seems suspicious but users can always change the default behavior by altering their respective sites' security preferences.
What Happens To The Previous CAPTCHA?
reCAPTCHA version 2 — the "I'm not a robot" checkbox — is still operational and Google continues to offer the simple service. The only thing that changed is that site owners who want a stealthier approach can now switch over to the invisible reCAPTCHA, which most users would not see unless their computers are somehow driving suspicious traffic.
Watch the short video below to know more.