Abstract: Method in which: a first terminal transmits K cryptograms KA*k,20 and a digital imprint KA20-Check of a key KA20, each cryptogram KA*k,20 having been obtained by encrypting the key KA20 with the aid of a respective key KSk,20 constructed on the basis of a characteristic datum extracted from electromagnetic waves received by this first terminal, a second terminal: decrypts each cryptogram KA*k,20 received with the aid of a key KSm,22 and thus obtains a key KA22, each key KSm,22 having been constructed by proceeding just as for the keys KSk,20 but by using the characteristic data extracted from electromagnetic waves received by this second terminal, constructs a digital imprint KA22-Check of each key KA22, only for the key KA22 obtained for which the digital imprints KA20-Check and KA22-Check are identical, stores this key KA22 as being the key shared with the first terminal.

Abstract: A method for transmitting and receiving multimedia content having cryptoperiods scrambled by a control word includes a sender using an operating key and an encryption algorithm in a first virtual mother card to encrypt the control word to obtain a cryptogram, using a syntax constructor also in the first virtual mother card to generate an ECM that incorporates the cryptogram, and transmitting it to a terminal. The terminal receives the ECM and using a syntax analyzer contained in a first virtual daughter card associated with the mother card and uses it to locate a position of the cryptogram CW*t in the ECM. Using an operating key of a decryption algorithm in the daughter card, it then decrypts the cryptogram. Then, using the decrypted control word, it proceeds to descramble the cryptoperiod. Meanwhile, the sender occasionally changes the virtual mother card into a different virtual mother card.

Abstract: A method for protecting recorded multimedia content and enabling the recorded multimedia content to be shared between recorders and readers of multimedia content connected to one another via a wide area information transmission network.

Abstract: This security method for scrambled multimedia signal decoder comprises at least one rewritable lock (62, 64), the value of which can be toggled at least between a first and a second value in response to an EMM message, and in which a registration module is able, in response to one and the same EMM registration message for writing new access entitlements or new cryptographic keys, to authorize and, alternatively, to prohibit this registration depending on the value of the lock.

Abstract: This method for detecting an illicit use of a security processor used for the descrambling of different multimedia contents disseminated on several respective channels comprises: the incrementing (153) of a counter Kchi by a predetermined step whenever, after verification, a message ECMi,c is received within a time slot immediately consecutive to a message ECMi,p and, if not, the resetting (158) of the counter Kchi at its initial value, the detection (162) of an illicit use as soon as the counter Kchi reaches a predetermined threshold.

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 protecting recorded multimedia content and enabling the recorded multimedia content to be shared between recorders and readers of multimedia content connected to one another via a wide area information transmission network.

Abstract: A method for transmitting and receiving multimedia content having cryptoperiods scrambled by a control word includes a sender using an operating key and an encryption algorithm in a first virtual mother card to encrypt the control word to obtain a cryptogram, using a syntax constructor also in the first virtual mother card to generate an ECM that incorporates the cryptogram, and transmitting it to a terminal. The terminal receives the ECM and using a syntax analyzer contained in a first virtual daughter card associated with the mother card and uses it to locate a position of the cryptogram CW*t in the ECM. Using an operating key of a decryption algorithm in the daughter card, it then decrypts the cryptogram. Then, using the decrypted control word, it proceeds to descramble the cryptoperiod. Meanwhile, the sender occasionally changes the virtual mother card into a different virtual mother card.

Abstract: This method for detecting an illicit use of a security processor used for the descrambling of different multimedia contents disseminated on several respective channels comprises: the incrementing (153) of a counter Kchi by a predetermined step whenever, after verification, a message ECMi,c is received within a time slot immediately consecutive to a message ECMi,p and, if not, the resetting (158) of the counter Kchi at its initial value, the detection (162) of an illicit use as soon as the counter Kchi reaches a predetermined threshold.

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 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: A method of broadcasting a scrambled multimedia programme, by way of a broadband network, in which before transmitting a license key: —a network head carries out a step of authenticating a terminal, and—if the terminal has been successfully authenticated, the network head 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 programme broadcast.

Abstract: The invention relates to an access control method controlling access to a broadcast digital dataflow previously scrambled. The method according to the invention includes the following steps: On transmission: generating an entitlement control message R-ECMc for recording the content of the flow as a function of a key KRc and at least one criterion CRR defining a right to the record, generating an entitlement control message P-ECMc controlling access to play back the content of the recorded flow as a function of a key KPc and at least one criterion CRP defining a right to play back, and on reception: analysing the messages P-ECMc and P-ECMc, authorizing the recording and playback if the criteria CRR and CRP are verified.

Abstract: This security method for scrambled multimedia signal decoder comprises at least one rewritable lock (62, 64), the value of which can be toggled at least between a first and a second value in response to an EMM message, and in which a registration module is able, in response to one and the same EMM registration message for writing new access entitlements or new cryptographic keys, to authorize and, alternatively, to prohibit this registration depending on the value of the lock.

Abstract: The invention relates to a method for controlling access to a transmitted digital data stream which has been previously encrypted. The inventive method comprises the following steps: upon transmission, generation of a message R-ECMc for controlling the right of access to the recording of the contents of the flow according to a key KRc, in addition to at least one criterion CRR defining a right to said recording; generation of a message P-ECMc controlling the right of access to playback of the contents of the flow recorded according to a key KPc and at least one criterion CRP defining a right to playback, and upon reception, analysis of messages R-ECMc, and P-ECMc, and authorization of recording and playback if criteria CRR and CRP are verified.