How to generate a Site Key and a Secret Key?

To generate a Site Key and a Secret Key, please follow the steps:

1. Click here to enter the form of registration for a new site where the ReCaptcha API will be used;
2. Set the name;
3. Select the Invisible reCAPTCHA option;
4. Define the domain of your website;
5. Tick the Terms of use checkbox;
6. Press the 'check in' button:

Then copy the Site key from this page:

And the Secret Key: