private jotform?

Is there a way to make a JotForm private and only allow a user to gain access it (fill it out) via the PHP API (or some other method?)

Basically, we would have our own php page call the JotForm with the API authentication key once we determined (on our end) that the user is allowed to access the JotForm. I *think* from what I've read the API is only used to retrieve results etc and not restrict access to the JotForm. But I wanted to make sure I didn't miss something. 

Thanks for your time.

I think you can make this question directly to api@jotform.com, they are more capable to answer this.