Brian S. Reed

The new reCAPTCHA is here and now you can add it to your Contact Form 7 forms.
A significant number of your users can now attest they are human without having to solve a CAPTCHA. Instead with just a single click they’ll confirm they are not a robot. Google calls it the No CAPTCHA reCAPTCHA experience.
Why this plugin is different from the others:
<ul>
<li>reCAPTCHAs for multiple forms on the same page</li>
<li>define the API keys in your wp-config file to hide the settings page</li>
<li>Github repo – please help me keep it updated : https://github.com/iambriansreed/contact-form-7-recaptcha</li>
</ul>

Contact Form 7 reCAPTCHA

The new reCAPTCHA for Contact Form 7 forms. Use shortcode [recaptcha].

Roi Dayan

Add reCaptcha to registration form

Contact Form 7 reCAPTCHA vs My reCaptcha