ADVANCED FEATURES. 1. SECURITY.
Access to VNC desktop generally allows access to your whole environment, so security is very important. VNC uses a challenge-response password scheme to make the initial connection the server sends, a random series of bytes, which are encrypted using the password typed in and then returned to the server which checks them against the right answer. Since VNC runs over a simple single TCP/IP socket, it is very easy to add support for SSL or some other encryption scheme.This is important to the user, or to tunnel it through something like SSH.
SSH allows redirection of remote TCP/IP ports so that all traffic is strongly encrypted and this can be combined with VNC .SSH can also compress the encrypted data .This can be very useful if using VNC over slow links.
In vnc,only first characters of passwords are significant. This is because of the get pass call in the UNIX server to read password has this restriction and other platform have been made compatible with this.