In my previous SG surveys, I’m pretty sure that our surveys’ URL reflected a secure server (https://).
I am finishing up a new survey, ASD senior survey (http://www.surveygizmo.com/s3/2538621/ASD-Senior-Survey); and I noticed that it is not secure.
The links are NORMAL by default. To change to a SECURE link, click on the CUSTOMIZE THIS LINK link on the SHARE page. On the left side of the page you should see a question that allows you to select either NORMAL or SECURE links.
Your ADMIN can change the account settings so that links are SECURE by default.
You can review the documentation for details – http://help.surveygizmo.com/help/article/link/secure-links