Duration computing method in a security module

摘要

Example embodiments are directed to a duration computing method in a security module inserted into an apparatus including an internal clock. The apparatus may receive a digital data stream encrypted via control words contained in a control message ECM. The method may include receiving data coming from the internal clock of the apparatus including a current temporal information, storing the data representing the current temporal information in the security module, receiving the control message ECM to decrypt at least one control word, reading previous data representing a previous temporal information at a moment of processing the previous control message ECM, and processing the control message ECM when the current temporal information is temporally ahead of the previous temporal information.