Abstract: A method of restricting access to recorded digital data on a digital support medium (2) using an integrated circuit e.g. on a smart card (4) containing a first decryption key (Kf) characterized in encrypting with a corresponding encryption key (Kf) one or more elements of the volume descripter (V) of the support medium (2), recording the encrypted elements of the volume descripter together with non-encrypted data on the support medium and, when accessing the support medium (2), using the integrated circuit decryption key (Kf) to decrypt the encrypted elements of the volume descripter (V) and to supply a reader (5) with these elements so as to permit the reading and/or writing of non-encrypted data on the support medium (2).

Abstract: A modem device driver, particularly for use in a receiver/decoder (2020) for a digital broadcast system in which received signals are passed through a receiver to the receiver/decoder and thence to a television set. The receiver/decoder is controlled by a virtual machine (4007) which includes a run time engine (4008). The receiver/decoder includes a plurality of interfaces to external units, and logical driver devices for the interfaces. A device driver (500) for controlling a modem interface comprises a buffer memory (503) for receiving messages, a control memory (502) for storing control parameters, and a logic unit (501) for controlling the device driver and the flow of messages. The logic unit includes a comparator (511) for matching Event, ACK, an NACK patterns stored in the control memory against the end of messages stored in the buffer memory.

Abstract: A system for transmitting and recording digital data is included. Further, a system for transmitting transmit scrambled audio data that is to be recorded on a mini disc reader is included. A system for transmission and recording of digital data includes transmission means adapted to prepare and transmit scrambled digital data together with at least one encrypted control word and a digital recording device adapted to receive and record the scrambled digital data and encrypted control word on a digital support. The digital recording device further includes an access control means adapted to decrypt the control word and thereafter descramble the digital data during playback.

Abstract: A method for downloading an executable application into a decoder for a digital broadcast system, characterized in that the application is stored on a portable memory card introduced into a card reader in the decoder, the decoder reading and downloading the application from the card. Data may be preferably be stored in the smart card in a broadcast data format such as the MPEG format to permit the processing of such data in the same manner as the control unit of the decoder processes data downloading by a broadcast transmission. The invention extends equally to a decoder and a memory card for use in such a method.

Abstract: A method and apparatus for the transmission and reception of scrambled data is disclosed. In some embodiments, the method and apparatus includes transmitting a scrambled data stream to a decoder, sending the scrambled data stream to a portable security module inserted in the decoder, descrambling the scrambled data stream, encrypting a descrambled data stream, and using the encrypted data stream to the decoder, decrypting the encrypted data stream, and using the decrypted data stream.