Right now, it's not possible to create and embed a secure form.
Please add support for https for the form builder.
Surprise! This is now live (minor miscommunication on our end regarding timing).
Go to the form in Net-Results and click “Get Source”. Replace the old embed code with that code and you should be good to go!
Ben Finklea commented
Thank you very much!!!!
Erik Wagner commented
This should be made a high priority. Google recently announced that they are giving organic ranking priority to websites that are secure (http://googleonlinesecurity.blogspot.co.uk/2014/08/https-as-ranking-signal_6.html).
Any ETA on this feature request?