| 摘要 |
A mobile terminal 3 is able to download data from content provider 15. The data is encrypted. To decrypt the data, the mobile terminal 3 obtains a licence from DRM broker 17. The DRM broker 17 transmits a licence including a decryption key to the mobile terminal 3 via short message service centre 7 associated with the mobile network 1 to which the mobile terminal 3 belongs. This data is encrypted using a public key of a public-private key pair. This public key corresponds to a private key 21 stored on the SIM 19 of the mobile terminal 3. Therefore, the licence data from DRM broker 17 can only be decrypted using the SIM 19. To prevent the SIM 19 being placed in another mobile terminal to decrypt corresponding licence data without an appropriate payment to DRM broker 17, the SIM 19 is "locked" to the mobile terminal 3 either by physical manufacture or by providing the mobile terminal 3 and the SIM 19 with a "shared" secret key 27,31. All communications between the SIM 19 and the core operating system 25 within the mobile terminal 3 are encoded using the shared secret key 27,31. Therefore, if the SIM 19 is removed from mobile terminal 3 and placed in another mobile terminal, communication between the SIM 19 and the other mobile terminal will not be possible as the other mobile terminal will not have a secret key corresponding to the shared secret key 27 of the SIM 19. |
