The Virtual Private Network

Once we have authenticated, we can encrypt. Anumber of techniques are used to provide
distance between the user and any (legitimate or nonlegitimate) third parties who
wish to read the user’s plaintext files. These techniques include the use of nonlinear
feedback registers.
The combination of authentication and encryption allows a network operator to
provide a virtual private network over a public access network. The virtual private network
includes delivery and storage bandwidth. As we will see in later chapters, storage
bandwidth can be enhanced by providing archiving, management, search and
retrieval systems, and (possibly) higher levels of access security than will be available
in a private network.