METHOD AND SYSTEM FOR RECEIVING A MULTIMEDIA SIGNAL, CRYPTOGRAPHIC ENTITY FOR SAID RECEPTION METHOD AND SYSTEM, AND METHOD AND BLACK BOX FOR PRODUCING SAID CRYPTOGRAPHIC ENTITY

摘要

The present invention relates to a method for receiving a scrambled multimedia signal by a control word. The method uses a first cryptographic entity that can be connected with any one of the P second cryptographic entities to form part of an apparatus for receiving a scrambled multimedia signal. Only the second cryptographic entities of a group of N second cryptographic entities selected from a broad set of P second cryptographic entities by varying the same root key as the root key used to obtain the session key of the first cryptographic entity. Use the session key obtained. ; Multimedia signal, entity, control word, scramble, descramble, encryption, decryption, session key, root key, identifier,