Laboratoire Europeen De Recherches Electroniques Avancees, Societe En

Laboratoire Europeen De Recherches Electroniques Avancees Societe En Nom

Laboratoire Europeen De Recherches Electroniques Avancees

Laboratoire Europeen De Recherches Electroniques Avancees Sociate En Nom

Michel Leduc

Eric Diehl

Joel Hamon

Jean-Claude Guillon

Francis Renard

Albert Dorner

Jacky Mahler

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.

Process for authentication of smart cards, and device for use of the

To counter illicit prevention of the invalidation of a smart card in a pay television network, for example when the period of validity for the card has expired, a verification of the card reader's ability to write to the card's memory is made. This verification consists in periodically sending a data item to be stored in the card. A counter on the card is reset by the writing voltage of the card's storage. In the event the writing voltage does not reach the counter, the counter's overflow output is connected to a read inhibition circuit which blocks functions of the card.

Protection against the non-authorized inhibition of writing in certain

According to the disclosed method, a reference line is caused to be transmitted during the non-visible part of the image, the transmissions are received with a calibrated receiver, this reference line is sampled, an error signal is produced from the difference between this line and its theoretical value, a correction coefficient is deduced therefrom for each of the samples of the line, and this correction coefficient is applied to the lines of the following frames.

Method for the correction of television signals at transmission, and

The method of the invention consists, during the transmission of composite video signals, in the inclusion therein of series of access messages (ECM1, ECM2) and, during the unscrambling, carried out using a chip card reader whose chip card comprises encoded digital data, in using an interactive method of identification of a digital signature.

Scrambling and unscrambling method for composite video signals and

According to the disclosed method, decoys which are the reproduction of the corresponding interpolated sequence are inserted into the scrambled line, at the end of the first section and at the start of the second section.

Method of protection against the unauthorized unscrambling of scrambled

The process of the invention concerns pay television networks with reinforced scrambling. To attract potential subscribers, the invention consists in cyclically transmitting non-scrambled images for brief periods, so that the type of program can be seen.

Process for promotion of pay television broadcasts, and device for use

To allow teleshopping to be performed quickly and reliably via the television network, receivers (3) are equipped with smart card readers (4), and the transmitter (2) sends information which is processed in the smart cards by means of the viewers' control devices (6). The result of this process is displayed on the screen and communicated later to the transmitter. This result allows the viewers' reactions to be authenticated.

Process for instantaneous confirmation of actions in relation to

To prevent a person having found or stolen a card of a pay-television subscriber from using it fraudulently, the identity of the subscriber is recorded in a zone protected from reading and writing. At the beginning of the period of use of a new card, the new card compares the identity of the new card with that of the old one, and delivers the password only if the two identities are the same.

Growing community of inventors

Boersch, France

Michel Leduc