| 摘要 |
<p>A method for securely transferring a content CT between devices (10, 20) within a network managed by a management center (1). Each device (10, 20) has a pre-initialized secret value S1, S2. For each of these devices, the management center (1) has a device key K and a device value V which is the result of a preliminary cryptographic operation of the device key K by means of the secret value S belonging to said device. The method comprises:
an activation of the network comprising the steps of:
- generating a network key KN, then calculating, for each device, an encrypted network key KN' which is the result of the encryption of the network key KN by means of the corresponding device key K, then transmitting to each device its device value V and its encrypted network key KN',
a keys recovering phase comprising the steps of:
- performing at said devices (10, 20) a first cryptographic operation for obtaining the device key K from the received device value V and from the secret value S of said device,
- performing at said devices (10, 20) a second cryptographic operation for obtaining the network key KN from the received encrypted network key KN' and from the device key K,
a transfer of a content CT comprising the steps of:
- generating a random value RV at a sending device (10), then performing a third cryptographic operation for generating a content key Kc from said random value RV and from the network key KN, then
- encrypting the content CT with said content key Kc, then sending the encrypted content CT' and the random value RV to at least one of said devices acting as a receiving device (20),
or
- encrypting the content CT with said random value RV, then sending the encrypted content CT' and the content key Kc to at least one of said devices acting as a receiving device.</p> |
