Google reCAPTCHA ensures that a human being, rather than a computer (or “bot”), is interacting with your website. Unlike the standard Magento CAPTCHA, Google reCAPTCHA provides enhanced security with a selection of different display options and methods. Additional website traffic information is available in the dashboard of your Google reCAPTCHA account.
This module provides the base implementation for reCAPTCHA.
For more information please visit the Magento document for reCAPTCHA.