How to force ddclient to use only HTTPS?

I’m running ddclient on Arch Linux with Namecheap. I want to force ddclient to use only HTTPS.

Ddclient is a Perl client used to update dynamic DNS entries for accounts on ‘Dynamic DNS Network Services’ free DNS service.

In the file /etc/ddclient/ddclient.conf I have ssl=yes

I don’t see another ddclient config setting related to this. Is there a way I can accomplish my goal?