The local digital network comprises: access devices, for receiving data
originating from outside the network and transmitting them at a point of
the network; and presentation devices for receiving the data flowing in
the network and presenting them at a point of the network. The data flow
in the network in encrypted form and all the devices of the network use a
single key, the local key of the network, for the encryption and
decryption of the data. Preferably, the local key of the network is
formed by a pair of public and private keys. The purpose of this network
is to make it possible to copy data in the local network whilst
preventing pirate copies destined for other local networks.