MEMORY CARD-BASED CONDITIONAL ACCESS SYSTEM FOR MOBILE BROADCAST

摘要

The present invention relates to a memory card-based conditional access system (CAS) for mobile broadcasts that enables CAS services to be handled in the memory card. To this end, the present invention executes the generic bootstrapping architecture (GBA) between the CAS client and the bootstrapping service function/home subscriber system (BSF/HSS) in the memory card loaded in the CAS client so that the memory card loaded in the CAS client shares a shared key (KS) with the BSF/HSS. In addition, a long-term key message (LTKM) received from the CAS server is encrypted with a subscriber management key (SMK) induced from the KS to obtain a service encryption key (SEK) (or program encryption key (PEK)) to provide a traffic encryption key (TEK), and it is preferable that safe delivery to the descrambler of the TEK thus obtained be effected in the memory card.  The present invention executes the decryption of the keys (SMK, SEK/PEK, TEK) and messages, including GBA, required to view the encrypted contents, within the memory card, thereby ensuring safe management of the keys (SMK, SEK/PEK, TEK).