| 摘要 |
The aim of this invention is to propose a method to supply a control of the validity duration of a right registered in a security module in absolute terms by means of a management of the different received parameters allowing the determination of an expiry date and time. The aim is achieved by a duration computing method in a security module inserted into an apparatus comprising an internal clock; this apparatus receiving a digital data stream encrypted by control words contained in the control messages ECM, this method comprising the following steps: reception of data coming from the internal clock of the apparatus comprising a current time information, storage of the current data representing the current temporal information in the security module, reception of a control message ECM requiring the decryption of at least one control word, reading of previous data representing previous temporal information at the moment of the processing of the previous control message ECM, processing of the control message ECM when the current information is temporally ahead of the previous information.
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