I was thinking of using Linux Deploy to install Ubuntu in Nexus 9 (2014) Device. I Would be using the VNC viewer by "realvncunlimited" and Linux deploy by "meefik". My question is, how secure will the connection be between the VNC viewer and the Linux os on the device? Is there encryption or SSH, and will this get sniffed on wireless if there are none of those securities (Is the VNC even traveling outwards to a router or in the device the whole time?). I understand that a normal VNC connection will go from the device to the router (or whatever else in use) to the computer, but this connection may remain in the device. Please help, I will accept any answer pertaining to the topic of VNC security, although a definite answer will help my project very much.
The data won't travel outside your device at all. If you're paranoid, turn on airplane mode and you'll see it still works. An exception is if you're connecting to the Internet with the distro to download packages etc but that's a given.
The data sent by the RealVNC Server are not encrypted (see RealVNC documentation). You need to upgrade to a commercial licence to enable encryption.
You can use SSH tunnelling, which will wrap the connection between VNC viewer and server into an SSH tunnel, which is (can be) encrypted. TightVNC does that, and it's the VNC server used in Linux Deploy. Just use the
-via <gateway> option (check the documentation).