The conditional access system of the present invention allows a service provider to supply services, which may be scrambled by a control word, only to those users who have acquired entitlements to these services. The control word is supplied in Entitlement Control Messages (ECM) after having been encrypted...http://www.google.fr/patents/US6035038?utm_source=gb-gplus-shareBrevet US6035038 - Conditional access system and smartcard allowing such access
Conditional access system and smartcard allowing such access
