Abstract: A Method for supplying protected multimedia content during which a terminal a) acquires a service date from a date server and b) evaluates a temporal criterion of a licence with respect to the last acquired service date. A headend associates with each segment of the multimedia content, its transmission date, and transmits it in a stream together with the segment. The terminal extracts from the stream the date of transmission of the segment, then it compares the extracted transmission date to the last acquired service date. And, only if the extracted transmission date is later than the last acquired service date, acquires it as service date, and uses it as last acquired service date on an execution of the step b) between two successive executions of the step a).

Abstract: A Method for supplying protected multimedia content during which a terminal a) acquires a service date from a date server and b) evaluates a temporal criterion of a licence with respect to the last acquired service date. A headend associates with each segment of the multimedia content, its transmission date, and transmits it in a stream together with the segment. The terminal extracts from the stream the date of transmission of the segment, then it compares the extracted transmission date to the last acquired service date. And, only if the extracted transmission date is later than the last acquired service date, acquires it as service date, and uses it as last acquired service date on an execution of the step b) between two successive executions of the step a).

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 relates to a method of transmitting at least one additional piece of data D in a list of access control words CWi to a scrambled content transmitted by a content server of an operator to a user equipment (2) including a reception terminal (4) associated with a security processor (6), each control word CWi of said list being designed to descramble said contents during a determined cryptoperiod, this method includes the following steps: a) prior replacement of at least one of the control words of said list with a magnitude X resulting from the treatment of said additional piece of data D by a function G having a dual function H, and, at the reception of said list by the 15 reception terminal (4), b) retrieve said additional piece of data D by treating said magnitude X with dual function H.

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: 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: 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 relates to a method of detecting an abnormal use of a security processor invoked by at least one receiving terminal in order to control access to a scrambled digital content supplied by at least one operator to said receiving terminal. This method comprises the following steps: analysing security processor use during a preset observation period TObs, determining on the basis of said analysis the mean value MECM of the number of invocations per time unit of said security processor during said observation period TObs, comparing said mean value MECM with a preset threshold Smax, and if the value MECM is greater than the threshold Smax, applying to said terminal a sanction whereof the level of severity increases progressively.

Abstract: The invention relates to a method of transmitting at least one additional piece of data D in a list of access control words CWi to a scrambled content transmitted by a content server of an operator to a user equipment (2) including a reception terminal (4) associated with a security processor (6), each control word CWi of said list being designed to descramble said contents during a determined cryptoperiod, this method includes the following steps: a) prior replacement of at least one of the control words of said list with a magnitude X resulting from the treatment of said additional piece of data D by a function G having a dual function H, and, at the reception of said list by the reception terminal (4), b) retrieve said additional piece of data D by treating said magnitude X with dual function H.