METHOD, SYSTEM AND DEVICE FOR SECURELY TRANSFERRING CONTENT BETWEEN DEVICES WITHIN A NETWORK
A method for securely transferring a content CT between devices (10, 20) within a network. Each device (10, 20) comprises a pre-initialized unique secret value S which is different for each device. The method comprises: an activation phase comprising the steps of:generating, by a management center (1), a network key KN common to all of said devices (10, 20), calculating, by the management center (1), an encrypted network key KN' for each device (10, 20) by encrypting said network key KN by means of a device key K which is different for each device (10, 20), transmitting, by the management center (1) to each of said devices (10, 20), the encrypted network key KN' and a device value V resulting from a preliminary cryptographic operation of the device key K belonging to said device (10, 20) by means of its the secret value S, a keys recovering phase performed by each of said devices (10, 20) and comprising the steps of: -performing a first cryptographic operation for obtaining the device key K from the device value V and from the secret value S of said device (10, 20), performing a second cryptographic operation for obtaining the network key KN from the encrypted network key KN' and from the device key K, an operating phase performed by each device (10, 20) involved in the transfer of said content CT and associated data, comprising the steps of: generating, or extracting from said associated data during a third cryptographic operation, a random value RV that will be subsequently used for the encryption, respectively the decryption of said content CT, generating a final key by encrypting the random value RV by means of the network key KN or by using said random value RV as final key either directly or indirectly as provided by said third cryptographic operation, using said final key for encrypting or decrypting said content CT.