RealVNC is the default VNC server shipped with Raspbian, the official supported operating system for Raspberry Pi Board; it is free to use with Raspbian offering for free features from the paid version, such as direct connection with IP address.
It has the option to encrypt connection with a 128bit AES encryption (256bit for enterprise license) and to scale the size of the remote desktop to the size of the viewer application.
You can find more informations here:
It would be nice if those features will be available also for the embedded VNC viewer; AES for security reason and scaling for usability when used in tabbed mode.
As an alternative, it would be also nice if the RealVNC viewer can be used in embedded mode.
I will check what we can do but RealVNC does not usually publish the specification and it's no longer open source. We already checked to integrate RealVNC but they charge a really huge amount based on our user count. This is just not possible for us to afford.