Abstract: Method and a device for guaranteeing the integrity and authenticity of data transmitted between a management center and one or several receiver units, wherein each receiver unit comprises a decoder (IRD) and a security unit (SC) and means for communicating (NET, REC) with the management center. The method consists in calculating a check information (Hx) representative of the result of a unidirectional and collision-free function, performed on all or part of the transmitted data and in transmitting the result to the management center for verification. The center will be able to inform the decoder concerning the authenticity of the data through return channels or through the main channel.

Abstract: The aim of this invention is to propose an innovating way to offer access to paying TV to a large clientele all by drastically diminishing the costs connected to the management of the subscribers.

Abstract: This invention proposes a method for securing updating software in a plurality of decoders based on the generation of a signature by means of a private asymmetrical key. The updating of a decoder is carried out by downloading, from a managing center, a data block including a patch and its signature, said block is stored in a RAM. The signature is decrypted with a current public key from a list contained in a first non-volatile memory of the decoder, then verified and in the case of correspondence, a command leads the installation of the patch in a second non-volatile Flash memory and the deactivation of the current key. The aim of this invention is to considerably reduce the impact of the discovery of a private key by mean of a systematic analysis of the working of the decoder software, or to notably increase the time and the means necessary for the process used to determine said private key.

Abstract: The aim of the present invention is to propose a storage method of an event encrypted by control words (CW) that guarantees the access to this event whichever the moment, even if certain modifications in the designation of the identifiers of these events occur between the moment of storage and the moment of viewing.

Abstract: The objective of the present invention is to propose a storage method in a decoder of an event encrypted by control words that guarantees the access to this event at whichever moment, even if certain keys of the system have changed for security reasons.

Abstract: The objective of the present invention is to propose an accounting method of the consumption of transmitted services per time unit to a decoder in a system implementing a content encrypted by control words, the latter being modified according to a period named crypto-period.

Abstract: The invention refers to a method of updating a multi-operator reception system by administration (EMM) and updating messages between a subscriber management system and one or several decoders of pay television, being the functioning of the decoder dependent on the reception of administration (EMM) and updating messages of at least one preferential operator, this decoder having to pass into stand-by state under certain conditions.

Abstract: The objective of the present invention is to propose a method that guarantees the encryption of the exchanged data a security module and a user unit by a pairing key specific to the couple user unit/security module, and at the same time leaving the possibility for the security module to be paired with other user units.

Abstract: At the moment of the diffusion of Pay-TV with multi-channel signals, each channel is associated to authorization messages (ECM) which allow to decrypt this channel according to the rights of the subscriber. When changing channel, a very short time is accepted before one has determined these new rights in relation with the new channel. The heavy encrypting algorithms are thus excluded. To avoid this drawback, to decrypt a channel, a system is proposed using the combination of the authorization information for a channel (ECM), and thus encrypted by a fast algorithm, with authorization information (MECM) for a group of channels. These latter are encrypted by a high security algorithm and are thus slower to decrypt.

Abstract: System for controlling the transmission of information between a receiver and a security module, especially for a pay television system, in which the transmitted information is encrypted and decrypted by means of a unique encryption key stored, on the one hand, in the receiver and, on the other hand, in the security module.

Abstract: A method of production and distribution of asymetric public and private keys between a key generation centre and at least one user unit (DEC), the unit comprising a security module (SM), the method consisting in generating certificates comprising a public key and a private key in a first cryptographic unit (KPG), coding the private key by use of a service key in the first cryptographic unit (KPG) and storing the private key in a key memory (KPS), when sending the keys to a user unit, extracting the keys from the key memory (KPS), composing the certification with the public key, decoding the corresponding private key by use of the service key in a cryptographic security module and coding it with a transport key of the user.

Abstract: A method for providing Pay TV services to subscribers offers to the services provider enhanced flexibility in billing procedures and the marketing advantage of granting an initial credit to each subscriber upon his subscription.

Abstract: A decoder comprising a microprocessor connected to a receiver of data of teletext and to a text generator for displaying information on the screen of a television receiver. Further, a CPTV-card (card pay-television) is associated with the microprocessor, this card managing the credit necessary for the purchase of emissions, for the memorization of the emissions purchased and for permitting the unscrambling of the emissions purchased by delivering to the microprocessor the input pointer in the sequence which is calculated by the microprocessor by means of the information which has been memorized as well as the information delivered by the decoder. The programs of the forecasted emissions are transmitted by the head station and memorized in the microprocessor of the decoder. Another memory of the microprocessor contains the instructions for the manipulations to be effected for selecting an emission and for purchasing it as well as for recharging a credit in the CPTV-card.