Abstract: Methods of providing added security for communications between a server and a particular client modem on a shared communication media. The methods provide for passing communications containing scrambled keys to be used to form scrambling seeds for scrambling subsequent messages. In a preferred embodiment, both the server and the client modem generate and pass keys to be used for the communications between the server and that client modem to achieve a dynamic dual key scrambling system.

Abstract: A set of system configurations adapted to provide data communications to and from a set of client modems connected to one or more central modems through a tree and branch network such as exists in buildings, hotels, multiple dwelling units and the like to distribute cable television signals to individual rooms. The set of one or more central modems is connected directly or indirectly to one or more networks such as the Internet. Optionally, some components of this system can be placed at the cable television head-end for ease of access for maintenance.