Protect your website from spam and abuse by embedding reCAPTCHA in the rating form. You can register for reCAPTCHA API keys here. This plugin requires PHP >= 5.3 and Multi Rating Pro >= 4.0.12.
In the plugin settings under the reCAPTCHA tab, simply enter your reCAPTCHA API keys and then enable reCAPTCHA. Now reCAPTCHA will be embedded in the rating form and WordPress comment form if ratings are integrated.