Patent ID: 7433473

Claim:
Data transmission method between a diffusion center and a multimedia unit, the latter comprising a monolithic circuit having at least one unique key and a security module (MS) having a transport key, said diffusion center being connected to a management center, said management center having knowledge of the at least one unique key and the transport key, this method comprising the following steps: generating a session key in the management center, transmitting the session key to the diffusion center, encrypting the session key in the management center using the unique key of the monolithic circuit to produce a management message, encrypting the management message using the transport key, transmitting an encrypted management message to the multimedia unit, transmitting the encrypted management message to the security module by way of the multimedia unit, decrypting the encrypted management message using the transport key in the security module to produce the encrypted session key, transmitting the encrypted session key to the monolithic circuit, decrypting the encrypted session key in the monolithic circuit using the unique key of said monolithic circuit, creating a secure data transfer connection by using the session key to encrypt and decrypt data as it passes between the diffusion center and the multimedia unit.