A video decoder includes an application specific integrated circuit (ASIC) that has the decoder address and a secure decryption key stored in a one-time-programmable memory. Encrypted messages are received and selectively supplied to a packet decrypter and to a video decrypter based upon the location of bits in the message string. The packet decrypter is responsive to a flag in the packet data for utilizing a secure key or a unsecure key for decryption of the packet data. The information derived from the secure decryption and the secure key itself are never available (or ascertainable) outside of the ASIC. Only information concerning the unsecure key is available outside of the integrated circuit.

A communications network between a central station which broadcasts coded information and at least one receiver suitable for receiving and decoding these broadcasts, in which, in order to control the number of users, permission for users to access the network is determined by a limited number of special receivers respectively assigned to such users and also by the need to authenticate each user before granting access to the program by his receiver. In order to facilitate identification of the user and authentication of his access rights to a particular program, the receiver allows remote authentication, and also local authentication with a memory card in which information related to certain access rights is stored.

A community antenna broadcasting system comprises a transmitting center for broadcasting programs in physical channels, a transmission path, and one or a plurality of home terminals for receiving the programs broadcast from the transmitting center via the transmission path. The transmitting center transmits a main information which includes video and audio information for each of physical channels, and also transmits a control information which includes numbers of logical channels which are contents of the physical channels. The home terminal enters a supervision information which includes a number of a desired logical channel which corresponds to a desired program, and produces a channel selection instruction by collating the control information and the supervision information. A channel selection part is provided within the home terminal. The channel selection part receives the information via the transmission path and selects a physical channel in response to the channel selection instruction.

The device of the invention for a pay-television system comprises an emitter and several receivers using "smart cards". In addition to the unscrambling control signals, the emitter sends encrypted authentication messages to which a correct response can be given only by the receivers where valid cards are used.

An information broadcast system having a broadband broadcast system selected from cable and satellite for broadcasting requested information from a selected information source, including the Internet, to one or more selected subscriber stations includes an independent backhaul channel for communicating information request signals from a subscriber station to one or more central processing stations. The system includes a data broadcast station for transmitting requested data from the selected data source and central station via the data broadcast station to the one or more selected subscriber stations. The high-data rate broadcast station forwards requested data from a data source to the data broadcast station. A backhaul satellite communication system, independent of the broadband broadcast system, has a backhaul satellite ground terminal for coupling information request signals from backhaul satellite communication system to high data broadcast station terminal. Each subscriber station has a broadband broadcast receiver for receiving requested information broadcast by the high data rate broadcast and a satellite antenna for transmitting backhaul request signals to the backhaul satellite.