Patent ID: 8879739

Claim:
A method for securely transferring a digital content CT between electronic devices within a network managed by a management center, each device comprising a pre-initialized unique secret value S, an activation phase performed by the management center and including the steps of, generating a network key KN common to all of said devices, calculating, an encrypted network key KN′ personalized for each device by encrypting said network key KN using a personal device key K which is different for each device, transmitting to each of said devices the encrypted network key KN′ and a device value V resulting from a preliminary cryptographic operation encrypting the device key K belonging to said device using the secret value S of said device, a keys recovering phase performed by each of said devices and including the steps of, performing a first cryptographic operation for obtaining the device key K from both the device value V and the secret value S of said device, performing a second cryptographic operation for obtaining the network key KN from both the encrypted network key KN′ and the device key K, an operating phase including the steps of, generating a random value RV at one of said devices acting as a sending device, performing, at the sending device, a third cryptographic operation for generating a content key Kc by encrypting said random value RV using the network key KN, and executing at least one of the following steps, encrypting the content CT using said content key Kc to obtain an encrypted content CT′, then sending the encrypted content CT′ and the random value RV to at least one of said devices acting as a receiving device, or encrypting the content CT using said random value RV to obtain an encrypted content CT′, then sending the encrypted content CT′ and the content key Kc to at least one of said devices acting as a receiving device.