Wanting to avoid bots registering on a website, I might use reCAPTCHA by Google. Since the algorithm behind reCAPTCHA is not open source, I'm wondering what user information they actually collect about the person registering on the website.
In my researches, I found out that they probably check at :
- Loaded resources
- Whether you have a google account or not
- Behavior on the page
- Past history and cookies
Which is already a good list of information. But is it also possible that they look at the information the user filled the form with?