Information processing apparatus, content information management method and computer program

• US 7,885,895 B2
• Filed: 08/05/2004
• Issued: 02/08/2011
• Est. Priority Date: 08/07/2003
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Asano, Tomoyuki
• Primary Examiner(s): Elisca; Pierre Eddy
• Assistant Examiner(s): Kamal; Shahid
• Application Number:
  US10/912,457
• Publication Number:
  US 20050071279A1
• Time in Patent Office: 2,378 Days
• Field of Search: 705/7, 705/57, 705/51, 705/52, 705/64, 380/3, 380/4, 380/25, 380/201, 380/202, 709/217, 709/225, 709/229, 709/231, 709/232, 725/30, 725/31, 725/87, 725/104
• 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. A method of providing content to a terminal device in a network, the method comprising:

storing, in memory, a first content encrypted by a first content key, the first content key encrypted by a first network key, a second content encrypted by a second content key, and the second content key encrypted by the first network key;

storing, in a network key storage, the first network key, wherein the first network key is shared with the terminal device;

receiving a second network key as an update of the first network key, wherein the second network key is shared with the terminal device;

receiving a request for the first content;

performing a key update triggered by the request, the key update comprising;

decrypting the first content key with the first network key;

encrypting the decrypted first content key with the second network key;

decrypting the second content key with the first network key;

encrypting the decrypted second content key with the second network key; and

storing, in the memory, the second content key encrypted by the second network key; and

sending the first content encrypted by the first content key and the first content key encrypted by the second network key to the terminal device in response to the request.

2. The method of claim 1, further comprising:

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

transferring the second network key from the current network key memory to the network key storage upon performing the key update.

3. The method of claim 2, further comprising:

encrypting the decrypted second content key with the second network key stored in the current network key memory.

4. The method of claim 1, further comprising:

selecting a network key to be deleted from the network key storage;

deleting the selected network key from the network key storage; and

storing an updated network key in the network key storage to replace the selected network key.

5. The method of claim 4, wherein the selected network key is the first network key, the updated network key is the second network key, and wherein the deleting occurs after performing the key update.

6. The method of claim 4, wherein the selected network key is the oldest network key in the network key storage.

13. The method of claim 1, further comprising:

periodically receiving updated network keys also shared with the terminal device; and

maintaining, in the network key storage, those of the periodically received updated network keys that encrypt one or more content keys stored in the memory.

14. The method of claim 1, wherein the network key storage comprises one or more tables.

7. A non-transitory computer-readable medium having tangibly embodied thereon program instructions, which, when executed by a processor, cause the processor to perform a method of providing content to a terminal device in a network, the method comprising:

storing, in memory, a first content encrypted by a first content key, the first content key encrypted by a first network key, a second content encrypted by a second content key, and the second content key encrypted by the first network key;

storing, in a network key storage, the first network key, wherein the first network key is shared with the terminal device;

receiving a second network key as an update of the first network key, wherein the second network key is shared with the terminal device;

receiving a request for the first content;

performing a key update triggered by the request, the key update comprising;

decrypting the first content key with the first network key;

encrypting the decrypted first content key with the second network key;

decrypting the second content key with the first network key;

encrypting the decrypted second content key with the second network key; and

storing, in the memory, the second content key encrypted by the second network key; and

sending the first content encrypted by the first content key and the first content key encrypted by the second network key to the terminal device in response to the request.

8. The computer-readable medium of claim 7, the method further comprising:

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

transferring the second network key from the current network key memory to the network key storage upon performing the key update.

9. The computer-readable medium of claim 8, the method further comprising:

encrypting the decrypted second content key with the second network key stored in the current network key memory.

10. The computer-readable medium of claim 7, the method further comprising:

selecting a network key to be deleted from the network key table;

deleting the selected network key from the network key storage; and

storing an updated network key in the network key storage to replace the selected network key.

11. The computer-readable medium of claim 10, wherein the selected network key is the first network key, the updated network key is the second network key, and wherein the deleting occurs after performing the key update.

12. The computer-readable medium of claim 10, wherein the selected network key is the oldest network key in the network key storage.

15. The computer-readable medium of claim 7, the method further comprising:

periodically receiving updated network keys also shared with the terminal device; and

maintaining, in the network key storage, those of the periodically received updated network keys that encrypt one or more content keys stored in the memory.

16. The computer-readable medium of claim 7, wherein the network key storage comprises one or more tables.