[varenc]

Those URLs are temporary and locked to the IP that fetched them. You can't effectively share the URLs since they're generated uniquely per-client. Not sure if this changes anything though.

edit: some quick testing confirms these URLs are temporary, but they don't appear limited to the IP that generated them. Your IP is embedded in the URL though, and you can't modify it without breaking the URL, so I'm guessing some IP limits kick in at some point.