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 invention relates to a method for receiving a scrambled multimedia signal by means of a control word. Said method uses a first cryptographic entity that can be connected to any one of P second cryptographic entities in order to form part of a device for receiving the scrambled multimedia signal. Only the second cryptographic entities of a group of N second cryptographic entities selected from a wider set of P second cryptographic entities use a session key obtained by diversification of a root key identical to the root key used to obtain the session key of the first cryptographic entity.