title: What's the use of the Public and Private key for reCAPTCHA?
body: <p>reCAPTCHA requires a public and a private key before it can be implemented into a website. It also needs the reCAPTCHA keys depending on the website. What's the reason behind this? Does the Public and Private key affect the words displayed in the reCAPTCHA? I know that I can set the Public and Private key to be GLOBAL in which it can be used for other domains <b>but</b> why even need the keys in the first place?</p>