Abstract: This invention concerns a security module deactivation and reactivation method particularly intended for access control of conditional access data. These security modules include a plurality of registers (R1, R2, R3, Rn) containing values. The method includes the step of sending at least one management message (RUN-EMM) containing an executable code, this executable code being loaded into a memory of the security module and then executed. The execution of this code in particular can carry out the combination and/or the enciphering of the values of the registers, or render these values illegible. This method also allows the reactivation of the security modules that have been deactivated previously. In this case, the method includes the step of sending another message containing an executable code (RUN-EMM?1) for the reactivation of the modules, this executable code having an inverted function to that of the executable code used for the deactivation of the security modules.

Abstract: A method is for protecting an encrypted content, by use of at least one encryption key. The method includes generation of a temporary encryption key, encryption by the temporary key of a value allowing the determination of the encryption keys of the content, transmission of the encrypted value to a multimedia unit, and encryption and transmission of at least two cryptograms including the temporary key encrypted by an authorization key. The first cryptogram is encrypted by a first authorization key pertaining to a first security module and the second cryptogram is encrypted by a second authorization key pertaining to a group of security modules whose first security module is excluded.

Abstract: This invention relates to a management method for conditional access data processing by at least two decoders associated to a subscriber. These decoders include activation/deactivation means for conditional access data processing and local communication means structured to allow communication between the subscribers' decoders. This process comprises a reception step, by a first decoder's local communication means (10), of at least one message originating from at least a second decoder (STB) associated to said subscriber. Then, it comprises a step to determine the minimum number of different decoders of said subscriber from which said first decoder must receive messages, and a comparison step between on one hand the number of different decoders from which said first decoder has received a message and on the other hand the minimum number of decoders from which said first decoder must receive a message.

Abstract: A method is used to restore the security of a secure assembly such as a chip card, after the contents of its second memory zone have been read by a third party. The method is for generating a security key implemented by a secure module comprising a central unit, a first conditional access memory zone and at least one second memory zone containing all or part of the user program. The method includes reading of all or part of the second memory zone, and generation of at least one root key based on all or part of the second zone data and on at least one item of secret information stored in the first memory zone.

Abstract: For this reason, the present invention proposes to allow the development of a first security based on a first key towards a second security based on a second key, this operation being carried out in an environment unprotected by said open transmission, guaranteeing the same security level as if this operation was carried out locally in the place belonging to the system manager.

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.