Can selenium Grid and Node URLs be used with security?
Selenium is not supporting that.
For that purposes you should make a p2p connection between you and grid.VPN or ssh tunnel will work. Just forward remote server port to a local port:
ssh user@SERVER -L 4444:127.0.0.1:4444Now, connecting to a local 4444 port will forward you to the remote address "SERVER". All the connection is secured by ssh login/password now and the traffic is hidden in a secure tunnel.