Google reCaptcha

First, we need an API key, so head on over to https://www.google.com/recaptcha/admin. To gain access to this page you’ll need to be logged into a Google account. You’ll be asked to register your website, so give it a suitable name, then list domains (for example tutsplus.com) where this particular reCAPTCHA will be used. Subdomains (such as webdesign.tutsplus.com and code.tutsplus.com) are automatically taken into account.
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With that done you’ll be given a site key and its partner secret key:

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Site key you will add in html page:

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Secret key you will add in php_helper/_contact-process.php file:

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