Abstract: The invention relates to a method for matching a number N of reception equipment with a number M of external security modules, each reception equipment being provided with a unique identifier, and each external security module having a unique identifier and containing information about access rights of a user to digital data distributed by an operator. The method comprises the following steps: memorizing a list of identifiers of reception equipment in each external security module, memorizing a list of identifiers of external security modules in each reception equipment, and when an external security module is connected to data reception equipment, a check plan is carried out to determine whether or not the identifier for the security module is present in the list of memorized identifiers in the connected reception equipment, and the same check plan is carried out for the identifier in the list of identifiers memorized in the security module.

Abstract: A method for access control to a digital scrambled content distributed to a set of installed reception terminals including one master terminal and at least one slave terminal dependent on the master terminal. In the method the slave terminal systematically or occasionally returns at least one item of information about the access condition to the master terminal through a point-to-point link, to enable the master terminal to control access of the slave terminal to the content.

Abstract: A method for protecting content to be distributed to a pool of receiving terminals connected to a content distribution network and each having a specific security level depending on the technical securing means used, the method comprising the following steps: when sending, generating a key for scrambling said content, transforming said scrambling key using a first calculation module 26 arranged at the headend of said content distribution network, scrambling the content using the transformed key, transmitting the scrambled content and the scrambling key to the terminals, and, upon reception of said content and of the scrambling key by a terminal, transforming said scrambling key using a second calculation module arranged in said terminal, descrambling the content with the transformed scrambling key, the method also characterized by the steps consisting of, when sending, applying to said scrambling key, by means of said first calculation module, a function F defined according to the specific security lev

Abstract: Protecting data transmission, either multimedia or a control word, between a security processor and a terminal includes, at the security processor, building a current session key by root key diversification as a function of a parameter transmitted by the terminal, decrypting the data, encrypting it with the session key, and transmitting it, and at the terminal, decrypting it using a secret code to obtain plain data, recording, in advance, secret codes, each enabling decryption of only data encrypted by a corresponding session key obtained by root-key diversification with a parameter, which can be the transmitted parameter, receiving the parameter in a message that also contains the data to be decrypted by the security processor, and in response, selecting, from the secret codes, a code for decrypting the data encrypted with the session key, as a function of the parameter or another parameter in the message.

Abstract: A method of transmitting control words to terminals that are mechanically and electronically independent of one another includes transmitting, to a terminal, an absent control word in response to a request from the terminal that contains a cryptogram corresponding to the absent control word, for the terminal, selectively determining a number of additional control words to be transmitted to the terminal as a function of a probability that security of the additional control words is compromised, and transmitting, to the terminal, in addition to the absent control word, the determined number of additional control words to enable the terminal to descramble at least one additional cryptoperiod of the multimedia content in addition to the cryptoperiod of the multimedia content that can be descrambled using the absent control word.

Abstract: A method for deciphering control words for mechanically and electronically independent terminals includes causing first and second terminals to transmit a first and second cryptograms to a control-word server, causing that server to decipher them to obtain first and second control words for enabling descrambling of first and second multimedia content broadcast simultaneously on respective first and second channels, causing the server to transmit the control word to the respective terminals, the second control word obtained by deciphering the second cryptogram before the first terminal executes a channel change, and in response to the channel change, causing the first terminal to search to determine whether the second control word has already been transmitted in advance by the server before the channel change, and if the control word has been transmitted in advance, causing the first terminal to immediately start descrambling the second multimedia content with the second control word.

Abstract: This invention relates to a method for broadcasting digital data to a targeted set of reception terminals in which said data are previously scrambled by a series of control words transmitted in a conditional access control message. This method comprises the following steps: on transmission, particularise said access control message using a reversible function F for which the inverse function F?1 is executable only in terminals in the targeted set, and on reception, redetermine the original access control message in each terminal in the targeted set using said inverse function.

Abstract: This method in which an attempt to attack a security processor is detected by the security processor itself comprises: measurements (50) of several different events occurring independently of one another in the absence of attack attempts, building (52) the value of at least one attack indicator as a function of at least one index of concomitance between at least two different events measured, the index of concomitance representing the temporal proximity between the two different events measured, and detecting (54) an attack attempt if the value of the attack indicator crosses a predetermined threshold.

Abstract: This method for renewing the code of an algorithm comprises: receiving (122) a randomly drawn seed whose size in terms of number of bits, is at least four times smaller than the number of bits needed to encode the N numerical constants of the cryptographic algorithm, expanding (128) the seed deterministically to obtain a sequence of numbers whose size, in number of bits, is at least equal to the number of bits needed to encode the N numerical constants of the cryptographic algorithm, generating (132) N new numerical constants from the sequence of numbers obtained, and replacing (134) the N constants of the code of the cryptographic algorithm by the N new constants generated to obtain the code of a renewed cryptographic algorithm.

Abstract: A method for access control to a digital scrambled content distributed to a set of installed reception terminals including one master terminal and at least one slave terminal dependent on the master terminal. In the method the slave terminal systematically or occasionally returns at least one item of information about the access condition to the master terminal through a point-to-point link, to enable the master terminal to control access of the slave terminal to the content.

Abstract: A method of broadcasting a scrambled multimedia program, by way of a broadcast network, in which before transmitting a license key; a network head carries out a step of authenticating a terminal, and if the terminal has successfully authenticated, the network heads sends the terminal a license transmission message containing the license key or cryptogram of the license key, by way of a point-to-point link, and if the terminal is not successfully authenticated, the network head acts (at 200) in such a way as to prevent the complete descrambling by this terminal of the scrambled multimedia program broadcast.

Abstract: The invention pertains to a method for transmitting a piece of additional data from a security processor to an external apparatus, in which the transmission of the piece of additional data is done by delaying (98) the start of a transmission of an information frame from the security processor to the external apparatus by a time lag that is a function of the value of this piece of additional data.

Abstract: The invention concerns a method for broadcasting a plurality of multimedia programmes generated by operators of different services, whereby one or more network headends broadcast (in 102) on a reference multicast address a list associating identifiers of service operators with at least one first level service multicast address, the reference multicast address being previously known to all the terminals capable of receiving and multiplexing broadcast multiplexed contents and said reference multicast address being different from all the broadcasting multicast addresses.

Abstract: The invention relates to a protocol for disabling/erasing access rights to scrambled data. According to the invention, the access rights entered in an access control module comprise the following variables: right identification variable (R ID), action date variable (AD V) and right status variable (S V). The status variable can have one of three encoded values, namely enabled, disabled or erased right. The inventive protocol consists in: transmitting (A) at least one access right management message comprising the right identification variable (R IDx), the action date variable (AD Vx) and the status assignment variable (S Vx), the latter corresponding to a enabled, disabled or erased right; assigning (B) the action date (AD Vx) of the message to the action date (AD V) of the right entered; and allocating (C) the status assignment variable (S Vx) of the message, corresponding to an enabled, disabled or erased access right, to the status variable (S V) of the entered access right.

Abstract: A method and system for distribution of scrambled data and/or services to at least one master terminal and to at least one slave terminal linked with the master terminal. The method and system transmit to the master terminal a first secret code and transmit to each slave terminal a second secret code in a biunique relationship with the first secret code, and authorize the reception of the data and/or services by a slave terminal only if the first secret code is previously stored in the slave terminal.

Abstract: The invention relates to a method for managing the number of visualizations of an audiovisual content, that comprises: providing a table containing an equal number of cells and of time segments of the audiovisual content, each cell being associated in a bi-unique manner with a respective segment of the audiovisual content; when a segment of the audio-visual content is read, incrementing (114) or decrementing by a predetermined step the number contained in the cell associated with the segment; and calculating (120) the number of visualization already done from the number recorded in each of the cells of the table.

Abstract: A method for transmitting entitlement management messages (EMM) controlling access to data and/or services to be provided to plural terminals in a data exchange network. The method, at the transmitting side: defines a set of EMM type messages as a function of at least one criterion representative of a type of data and/or services provided; defines plural types of logical transmission channels and associates at least one parameter to each type of channel to inform terminals of the EMM types transmitting on each described logical channel; assigns at least one channel among the defined logical transmission channels to each EMM message type; transmits the parameter and the logical channels to each terminal; multiplexes the logical transmission channels in the same data stream; and transmits the data stream to terminals. In the method, on reception each terminal filters incoming EMMs as a function of the parameter and at least one state parameter depending on a routine operation of the terminal.

Abstract: The invention relates to a method for a beneficiary to acquire a right to use a digital content in a contents distribution system comprising a commercial server (2), a rights server (4) and an operations platform (5) for said content, said platform (5) comprising at least one module (6) to purchase a usage right and at least one module (8) for using the purchased right, said purchase module (6) being capable of communicating with said commercial server (2) through a first application protocol specific to the commercial server (2), and said module (8) for using the purchased right being capable of communicating with said rights server (4) through a second application protocol specific to the rights server (4).

Abstract: The invention relates to a method for transmitting a message to a reception equipment by an operator, the message containing a description of an action to be executed in the said equipment at a time chosen by the operator. This method comprises the following steps: a—generate the said message as a function of the action to be executed, b—completely or partially encrypt the said message using a secret parameter, c—transmit the encrypted message to the said equipment, d—store the encrypted message in the reception equipment, and, e—at the time chosen by the operator, transmit a description for obtaining the said secret parameter to the reception equipment, and on reception, f—decrypt the encrypted message memorised in the reception equipment using the said secret parameter, g—process the said message so that the said action can be executed.

Abstract: A distribution process with access control of scrambled data to at least one receiver terminal. The process includes an encryption phase that subdivides the data into an integer of families each including an integer of blocks, assigns each family a specific identification parameter associated with at least one descrambling module having a specific processing capacity and a level of security, and scrambles each block of a family of a type by a key in biunivocal relation with the parameter. A descrambling phase identifies the family of each block and descrambles each block of a family of the type by the descrambling module by the key.