It's good to hear you got the digest authentication to work. I hope that alleviates, at least a little, some of your security concerns. The only thing I can offer at this time is for you to add an auth token to your WebDAV url and change/validate it accordingly. It involves a bit of work on your end but at this point is the only thing I can suggest.
Your original concern is definitely valid and has been taken note of on our end. I am confident we will implement a fix in the medium-term to address it.