Public key:
The public key you must get from Google in order to use the Google reCaptca web-service.
Private key:
The private key you must get from Google in order to use the Google reCaptca web-service
Theme:
You choose between 4 different skin
'white'
Tab index:
The tab index of the text field where the user must enter the validation texts
Language:
The language you want the object translate the texts
Other fields:
The other fields are the texts displaied in the captcha object and when you choose Custom language you can customize all this texts. Like you can see in this image:
