The present invention relates to a method for creating and managing a local area network including at least one device for reproducing an encrypted data flow and a device for transmitting and re-encrypting all or part of said encrypted data, which devices include security modules. The method includes the steps of connecting a so-called master security module in one of the devices connected to the local area network, causing the master security module to generate a network key, securely transmitting the network key to one or more so-called user security modules, decrypting the data encrypted by the transmission and re-encryption device, re-encrypting the data with said device by means of a local key, transmitting the re-encrypted data to the reproduction device, and holding the reproduction device to perform decryption using the user security module associated therewith and provided with means for locating the local key.