In the past solving a Captcha meant repeating a set of distorted characters, selecting several images based on what they are showing or at least clicking a dedicated checkbox. We all know the process of selecting traffic lights or having to distinguish a motorcycle from a bicycle.
Since the launch of Google’s reCAPTCHA v2 in 2014 so called Invisible Captchas started to appear more and more. Invisible Captchas work with or without very little direct interaction from the user and use different techniques to distinguish between real humans and bots in the background.
How do Invisible Captchas work?
Invisible Captchas can’t rely on the user solving a challenge or interacting with the captcha directly, they instead distinguish between a real user and a bot in a different way. By tracking the behavior of the user (even across websites) and collecting information about them these Captcha systems can make an educated guess whether the user is human or not.
What information is tracked and collected differs for different Captcha systems. reCAPTCHA is known for tracking and collecting as much information about the user as possible which allows Google to identify real humans without having to challenge them with a manual Captchas in many cases. But it comes with the price of the user’s privacy.
Other Captcha providers offer a similar approach to reCAPTCHA. They offer an Invisible Captcha for enterprise customers which can distinguish between real humans and bots in a basic way. These providers don’t require the user to solve any puzzle if they can collect enough data to accurately guess whether the visitor is human.
Are Invisible Captchas truly invisible?
Captcha providers have failed to offer truly Invisible Captchas. They appear to be invisible in many cases but if they can’t collect enough user data or an user seems to be suspicious to them, they still require the user to manually solve a puzzle.
The only truly invisible captcha solution on the market is Friendly Captcha. Due to its cryptographic puzzle technology, it never requires the user to manually solve a Captcha challenge. If it suspects that a user is not a real human, it gives them a harder cryptographic puzzle to solve which takes a longer time solve, making automated spam prohibitively expensive. In the worst case, the user will have to wait a bit longer. This makes Friendly Captcha the most accessible and user-friendly Captcha solution.