Information processing apparatus, content information management method and computer program

• US 20050071279A1
• Filed: 08/05/2004
• Published: 03/31/2005
• Est. Priority Date: 08/07/2003
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Asano, Tomoyuki
• Granted Patent: US 7,885,895 B2
• Time in Patent Office: Days
• US Class Current: 705/57
• CPC Class Codes: G06F 21/10 Protecting distributed programs or content, e.g. vending or licensing of copyrighted material protection in video systems or pay television H04N7/16 ; Digital rights management [DRM]
• CPC Class Codes: G06F 2221/2107 File encryption
• CPC Class Codes: G06Q 20/382 insuring higher security of transaction
• CPC Class Codes: H04L 12/2803 Home automation networks
• CPC Class Codes: H04L 12/2823 Reporting information sensed by appliance or service execution status of appliance services in a home automation network device-related reporting H04L43/065; arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom H04Q9/00
• CPC Class Codes: H04L 2463/062 applying encryption of the keys cryptographic mechanisms or cryptographic arrangements for key distribution using key encryption key H04L9/0822
• CPC Class Codes: H04L 63/068 using time-dependent keys, e.g. periodically changing keys cryptographic mechanisms or cryptographic arrangements for controlling usage of secret information H04L9/088

Abstract

A content providing server connected to a home network or the like is configured in such a way as to store a content key, which is encrypted by a network key shared by network-connected devices and appropriately updated, in a storage together with encrypted content, and as to hold a network key table in which all network keys including all pre-update network keys, which are being applied to encrypted content keys, are registered and stored. This server performs a key changing operation of changing a content key, which is encrypted by a pre-update network key, to an encrypted key, to which an updated network key is applied, only when needed, for example, at an occurrence of utilization of the content. Consequently, this configuration prevents key changing operations from being wastefully performed. Thus, the processing load on the server is alleviated.

Claims

1. An information processing apparatus having a function of a content server for providing content to network-connected devices, the information processing apparatus comprising:

storage for storing encrypted content and an encrypted content key encrypted by an updated network key set as a key shared with the network-connected devices and including encrypted data of content key used in decryption of the encrypted content; and

a network key table in which network keys are registered and stored, including all pre-update network keys utilized as encryption keys for the encrypted content keys stored in the storage.

2. The information processing apparatus according to claim 1, further comprising a mechanism of maintaining in storage the encrypted content key encrypted by the pre-update network key stored in the storage, without performing a key changing operation using an updated network key as an encryption key.

3. The information processing apparatus according to claim 1, further comprising a mechanism of performing a key changing operation of an encrypted content key to an encrypted content key applying an updated network key, if the encrypted content key corresponding to content to be utilized is stored in the storage as an encrypted content key encrypted by a pre-update network key differing from the updated network key, on condition that an operation of utilization of the encrypted content stored in the storage is triggered.

4. The information processing apparatus according to claim 3, further comprising a mechanism of transmitting encrypted content stored in the storage and an encrypted content key applying an updated network key generated by performing the key changing operation, to a device requesting utilization of the encrypted content.

5. The information processing apparatus according to claim 3, further comprising a mechanism of performing a key changing operation of updating an encrypted content key to an encrypted content key applying the updated network key for all encrypted content keys applying a same pre-update network key as the pre-update network key applied to the encrypted content key corresponding to the content to be utilized, and deleting the pre-update network key from the network key table.

6. The information processing apparatus according to claim 1, further comprising:

current network key memory for storing an updated network key; and

mechanism of performing a process of transfer of the updated network key from the current network key memory to the network key table, if a storing process is performed against the storage of the encrypted content key applying the updated network key.

7. The information processing apparatus according to claim 6, further comprising a mechanism of:

performing encryption applying an updated network key stored in the current network key memory at event of generation of an encrypted content key corresponding to content newly inputted to the storage;

storing the encrypted content key generated by the encryption process; and

transferring the updated network key from the current network key memory to the network key table.

8. The information processing apparatus according to claim 1, further comprising a mechanism of selecting a network key to be deleted from the pre-update network keys already stored in the network table at time of storage of a new updated network key to the network key table, and storing the updated network key into the network key table if the deleting process is complete.

9. The information processing apparatus according to claim 8, further comprising a mechanism of acquiring an encrypted content key stored in the storage as an encrypted key applying the network key to be deleted;

performing a key changing operation for changing to an encrypted key encrypted by an encrypted network key to be stored in the network key table; and

deleting the network key to be deleted from the network key table if the key changing operation is complete.

10. The information processing apparatus according to claim 8, wherein the process of selecting the network key to be deleted is performed as an operation of selecting an oldest network key from pre-update network keys stored in the network key table.

11. The information processing apparatus according to claim 8, wherein the process of selecting the network key to be deleted is performed as an operation of selecting a network key from the pre-update network keys stored in the network key table which minimizes a number of necessary processes of performing the key changing operation.

12. A content information management method for use in a content providing server containing in storage, encrypted content and an encrypted content key encrypted by an updated network key set as a key shared with network-connected devices and including encrypted data of content key used in decryption of the encrypted content including encrypted, the method comprising:

judgment step of judging whether or not an encrypted content key corresponding to content to be utilized is stored in the storage as an encrypted content key encrypted by an pre-update network key differing from the updated network key, on condition that there is an operation of utilization of the encrypted content stored in the storage; and

key changing step of updating the encrypted content key to an encrypted content key applying the updated network key if it is judged in the judging step that an encrypted content key associated with content to be utilized is stored in the storage as an encrypted content key encrypted by an pre-update network key differing from the updated network key.

13. The content information management method according to claim 12, further comprising the step of transmitting the encrypted content stored in the storage and the encrypted content key applying the updated network key generated in the key changing step to a device requesting for utilization of encrypted content

14. The content information management method according to claim 12, further comprising the step of performing the key changing operation of updating an encrypted content key to an encrypted content key applying the updated network key for all encrypted content keys applying a same pre-update network key as the pre-update network key applied to the encrypted content key corresponding to the content to be utilized, and deleting the pre-update network key from the network key table.

15. The content information management method according to claim 12, further comprising the steps of:

storing the updated network key in a current network key memory; and

transferring the updated network key from the current network memory to the network key table if there is an operation of storing the encrypted content key applying the updated network key into the storage.

16. The content information management method according to claim 15, further comprising the steps of:

performing encryption applying an updated network key stored in the current network key memory at event of generation of an encrypted content key corresponding to content newly inputted to the storage;

storing the encrypted content key generated by the encryption process; and

transferring the updated network key from the current network key memory to the network key table.

17. The content information management method according to claim 12, further comprising the step of selecting a network key to be deleted from the pre-update network keys already stored in the network table at time of storage of a new updated network key to the network key table, and storing the updated network key into the network key table if the deleting process is complete.

18. The content information management method according to claim 17, further comprising the steps of:

acquiring an encrypted content key stored in the storage as an encrypted key applying the network key to be deleted;

performing a key changing operation for changing to an encrypted key encrypted by an encrypted network key to be stored in the network key table; and

deleting the network key to be deleted from the network key table if the key changing operation is complete.

19. The content information management method according to claim 17, wherein the step of selecting the network key to be deleted is performed as an operation of selecting an oldest network key from pre-update network keys stored in the network key table.

20. The content information management method according to claim 17, wherein the step of selecting the network key to be deleted is performed as an operation of selecting an network key from the pre-update network keys stored in the network key table which minimizes a number of necessary processes of performing the key changing operation.

21. A computer-readable program for causing a computer to perform the steps of a content information management process for use in a content providing server containing in storage, encrypted content and an encrypted content key encrypted by an updated network key set as a key shared with network-connected devices and including encrypted data of content key used in decryption of the encrypted content including encrypted, the program comprising:

judgment step of judging whether or not an encrypted content key corresponding to content to be utilized is stored in the storage as an encrypted content key encrypted by an pre-update network key differing from the updated network key, on condition that there is an operation of utilization of the encrypted content stored in the storage; and

key changing step of updating the encrypted content key to an encrypted content key applying the updated network key if it is judged in the judging step that an encrypted content key associated with content to be utilized is stored in the storage as an encrypted content key encrypted by an pre-update network key differing from the updated network key.