Abstract: An access control system for signal processing applications includes an integrated circuit (IC) card, or “smart” card, that provides both security control and data descrambling functions. A security control processor in the smart card IC performs functions such as entitlement management and key generation. The smart card IC also includes a descrambler for processing data, such as video data, at high data rates. Mechanical characteristics of the smart card satisfy the ISO standard 7816-1. In addition, the interface to the smart card is via eight-terminals arranged on the surface of the card in accordance with ISO standard 7816-2. The eight terminal interface provides both high speed data I/O (input and output) required for data descrambling and ISO standard low speed serial data I/O.

Abstract: The invention is to be used in the Digital Video Broadcasting—Common Interface environment for accessing the Conditional Access Module (CAM). The host application handles objects of the Conditional Access (CA) through a private Application Program Interface (API). Each CAM may have its own private CA API but the data channel remains identical whatever the CAM is. This new mode coexists with the two already defined modes: low level Man Machine Interface, and high level Man Machine Interface. If a Set top Unit “understands” the private CA Application Program Interface (API), then it may access the features of the plugged CA through its private CA API Protocol. Otherwise, it remains on the standard API. With this extension, an STU can have a Conditional Access User Interface which perfectly fits into the overall User Interface of the STU. Thus b broadcaster can ensure that its look and feel are respected on its STUs.

Abstract: The present invention relates to a process making it possible to control access to at least one terminal with address AD by at least one scrambled item with the aid of at least one control word. The process comprises a step making it possible to construct a descrambling item in the form of a message containing the control word, a datum making it possible to identify the scrambled item and the address of the terminal.

Abstract: A system comprising a first device including a controller and a lock manager, a second device coupled to the first device by a bus, and a third device coupled to the first and second devices by the bus. The controller and the lock manager of the first device operate to establish an exclusive communication relationship between the first device and one of the second or third devices.

Abstract: The invention relates to a method of access to data sets stored in a bulk memory. During an access time to a data set, the method provides for reading introduction data and exploiting these. This way the method overcomes the problem of long access times in a bulk memory. The method may notably be used when data sets are arranged sequentially on a sequential data carrier, which is for example the case for songs recorded on a magnetic tape. A device for implementing the method is also defined.

Abstract: The invention relates to a process for scrambling video data in the MPEG2 video format as well as to a process for descrambling data scrambled according to the process of the invention. The scrambled video data are the coefficients AC and/or DC arising from the “discrete cosine transform” operation which are associated with at least one block of at least one image coded in INTRA mode. The invention applies to conditional access systems such as, for example, pay television systems.

Abstract: A method for loading a user interface in a television system comprising a decoder and a removable smart card cooperating with the decoder, the decoder comprising a main user interface, the method comprising the steps of loading and storing by the decoder of the totality of a user interface module stored-on the smart card, the user interface module comprising data structures making reference to information destined to a user, the information being stored on the smart card, establishing by the decoder a relation between the main user interface and the stored user interface module in order to enable access by a user to the user interface module, and subsequently exchanging between the decoder and the smart card parts of the information upon commands issued by the user through the user interface module.

Abstract: A system for enhancing the security of the interface between a consumer electronic device and a removable security device is provided by protecting the audio/visual (A/V) stream descrambled in the removable security device. The protection involves dynamically computing a shared key followed by the rescrambling of the A/V stream.

Abstract: In a device for descrambling scrambled digital data, the digital data are grouped into parallel combinations of bits before being descrambled. The combinations of bits are descrambled and then split back into a serial stream of bits.

Abstract: The present invention concerns a method for cascading detachable conditional access modules as well as a circuit for inserting a predetermined sequence and a circuit for detecting the sequence. Each module receives a data stream formed of packets of fixed length separated by an interpacket space of fixed length. The interpacket spaces contain a constant predetermined sequence which does not interfere with the packets. The predetermined sequence may be used to regenerate a packet clock signal.

Abstract: Television receivers are increasingly making use of digital signal processing. Present-day television receivers use a line-coupled clock system in this case, since this produces an orthogonal pixel array for signal processing on the picture screen. The disadvantage of such a clock grid resides in its problematical generation, in particular when video recorders are used as signal source. According to the invention, video signals are digitized and processed by means of a free-wheeling system clock made from a quartz oscillator. In order not to have to use large buffer memories, the vertical deflection is synchronized with the input signal, but the number of lines per field or frame is varied.

Abstract: For audio coding, the MPEG-2 standard provides for a spatial representation by multi-channel reproduction. In order to ensure backwards compatibility with MPEG-1 signals, the signals of the multi-channel sound channels are matrixed. Before being matrixed, the audio signals generally have their levels reduced in order to prevent overdriving. In order to balance again the reduction at the encoder end, an option that is provided in the MPEG-2 standard is for a decoder to raise the output levels again. If, however, a transmission error then occurs in the multi-channel section, the decoder cannot carry out the reverse matrixing. In that case, only the MPEG-1-compatible signal component will be decoded. The auditory impression can therefore be disturbed in various ways during the changeover to MPEG-1 decoding.

Abstract: The invention relates to a process for protecting an information item transmitted from a security element to a decoder and a protection system using such a process. The information item is protected by encrypting within the security element the information item to be transmitted to the decoder and by decrypting this information item within the decoder. The invention applies to conditional-access systems.

Abstract: A method for replacing parts of a digitally coded picture (11) is proposed. The digitally coded picture (11) may correspond to a sub-picture which is displayed on the screen of a television set (10). In the method, each line of the picture (11) is run length-coded. The replaceable parts of a line of the picture are run length-coded separately. The part which replaces the replaceable, original part of a line of the picture (11) is run length-coded in such a way that it has the same number of data units (data bytes) as the original part of this line of the picture (11). The replacement of the data for the run length coding words is carried out in a memory device (51). The replacement is possible in a simple manner by virtue of the fact that the original part of a line of the picture and the new part of the line of the picture have the same number of data units. Moreover, a device for carrying out the method is also proposed.