Hi Grif,
In regards to your Method Customer Portal being Secure, we got you covered on this front. If you look at your URL for your Contacts Portal, you should see the beginning starts with HTTPS, the "S" is the most important aspect of this abbreviation because it stands for secure. From how I undetsand it, HTTP with an "S" uses an SSL Certificate, this is what makes it "secure".
I have provided a link here, this is a wiki page explaining HTTPS in detail, and how the Secure aspect of it works. I also found some good information from this forum post, please keep in mind that I can't gaurantee all information on these links are correct, but they should be accurate and you will likely find the same answers on other resource pages if you attempt to search for this. Hope this helps.
-Ben