Restrict Content Pro Math Verification
This is a simple add-on for Restrict Content Pro that adds a math verification field to the registration form, which helps to prevent bot registrations while also not driving your users crazy with difficult to read reCaptchas.
With Restrict Content Pro Math Verification add-on, you can add a simple math verification field to your membership registration form. In order to signup, the user must complete the simple addition problem.
This add-on is designed to completely prevent bot registrations, while still presenting a very human-friendly and easy-to-use registration process, unlike the experience users have when trying to fill out difficult-to-read reCaptchas.