Patent ID: 7305087

Claim:
Local digital network, in particular digital home network, comprising: at least one access device, capable of receiving data originating from outside said network and of transmitting them at a point of said network; and at least one presentation device, adapted to receive data flowing in the network so as to present them at a point of the network; in which the data are adapted to flow only in encrypted form between the access device and the presentation devices of the local network, all the devices of said network using for the encryption and decryption of the data flowing in the network a single encryption key specific to the network: the local key of the network, in which the data are encrypted using a public keys cryptographic system, wherein said local key of the network is formed by a pair of public and private keys: the local public key and the local private key of the network, wherein only the presentation devices connected to the said network contain the local private key, wherein at a given instant, a single presentation device of the network is authorized to transmit the local private key to a new presentation device apt to be connected to said network, and wherein at a given instant, a presentation device can be in only one of the following states: i) a first state, the virgin state, when the presentation device is connected for the first time to said network: ii) a second state, the genitor state, in which the presentation device is authorized to transmit the local private key of the network to any new presentation device apt to be connected to said network; iii) a third state, the sterile state, in which the presentation device is no longer authorized to transmit the local private key of the network to any new presentation device apt to be connected to the said network, a presentation device being adapted to change state only so as to pass to a state of higher rank.