Secure Escrow and Recovery of Media Device Content Keys

• US 20080005030A1
• Filed: 06/30/2006
• Published: 01/03/2008
• Est. Priority Date: 06/30/2006
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Scientific-Atlanta Incorporated (Cisco Systems, Inc.)
• Inventors: Schlarb, John M., Bacon, Kinney C.
• Granted Patent: US 9,137,480 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 21/31 User authentication
• CPC Class Codes: G06F 21/602 Providing cryptographic facilities or services
• CPC Class Codes: H04L 2209/60 Digital content management, e.g. content distribution
• CPC Class Codes: H04L 9/0894 Escrow, recovery or storing of secret information, e.g. secret key escrow or cryptographic key storage
• CPC Class Codes: H04N 2005/91364 the video signal being scrambled
• CPC Class Codes: H04N 21/2541 Rights Management protecting software against unauthorised usage in a vending or licensing environment G06F21/10; security in data switching network management H04L41/28; security management or policies for network security H04L63/20; access security in wireless networks H04W12/08
• CPC Class Codes: H04N 21/26613 for generating or managing keys in general key distribution for secret or secure communication involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP] H04L9/083; network support of key management H04L63/06; key management for network security in communication control or processing H04W12/04
• CPC Class Codes: H04N 21/835 Generation of protective data, e.g. certificates protecting software against unauthorised usage in a vending or licensing environment G06F21/10
• CPC Class Codes: H04N 5/76 Television signal recording
• CPC Class Codes: H04N 5/913 for scrambling ; for copy protection

Abstract

An embodiment of a method for secure escrow and recovery of media device content keys includes generating, with a first processor of a media device, an escrow key for encrypting a plurality of content keys, the content keys for encrypting instances of media content. The first processor of the media device encrypts the escrow key with a public key of a key clearinghouse. The escrow key, encrypted with the public key of the key clearinghouse, is stored in a storage location outside of the first processor of the media device.

Claims

1. A method for securing media content comprising:

generating, with a first processor of a media device, an escrow key for encrypting a plurality of content keys, the content keys for encrypting instances of media content;

encrypting, with the first processor of the media device, the escrow key with a public key of a key clearinghouse; and

storing the escrow key, encrypted with the public key of the key clearinghouse, in a storage location outside of the first processor of the media device.

2. The method of claim 1, further comprising:

encrypting an instance of media content to be stored on a first storage device of the media device with a content key;

encrypting the content key with the escrow key; and

storing the content key, encrypted with the escrow key, to the first storage device.

3. The method of claim 2, wherein the content key encrypted with the escrow key is stored to the first storage device in an escrow security package with an identity of the first processor.

4. The method of claim 2, further comprising:

retrieving the content key, encrypted with the escrow key, from the storage device;

decrypting the content key, encrypted with the escrow key, with the escrow key; and

decrypting the media content with the content key.

5. The method of claim 2, further comprising:

requesting a release of the escrow key associated with the first processor from the key clearinghouse, the request including the identity of a second processor.

6. The method of claim 5, wherein the step of requesting a release of the escrow key associated with the first processor from the key clearinghouse causes the key clearinghouse to:

determine whether the second processor is authorized to access the escrow key; and

if the second processor is authorized to access the escrow key, decrypt the escrow key, encrypted with the public key of the key clearinghouse, with a private key of the key clearinghouse.

7. The method of claim 6, wherein the key clearinghouse further:

re-encrypts the escrow key with a public key of the second processor; and

delivers the escrow key, encrypted with the public key of the second processor, to the second processor.

8. The method of claim 7, further comprising:

decrypting the escrow key, encrypted with the public key of the second processor, with the private key of the second processor;

decrypting the content key, encrypted with the escrow key, with the escrow key; and

decrypting the instance of media content with the content key.

9. The method of claim 1, wherein the first processor is a secure microprocessor.

10. A digital media device comprising:

logic configured to generate an escrow key, associated with a first processor of the digital media device, for encrypting a plurality of content keys for encrypting instances of media content;

logic configured to encrypt the escrow key with a public key of a key clearinghouse; and

logic for storing the escrow key, encrypted with the public key of the key clearinghouse, in a storage location outside of the first processor of the media device.

11. The digital media device of claim 10, further comprising:

logic for encrypting an instance of media content to be stored on a first storage device of the media device with a content key;

logic for encrypting the content key with the escrow key; and

logic for storing the content key, encrypted with the escrow key, to the first storage device.

12. The digital media device of claim 11, wherein the logic for storing the content key, encrypted with the escrow key, to the first storage device includes logic for storing the content key to the first storage device in an escrow security package with an identity of the first processor.

13. The digital media device of claim 11, further comprising:

logic for retrieving the content key, encrypted with the escrow key, from the storage device;

logic for decrypting the content key, encrypted with the escrow key, with the escrow key; and

logic for decrypting the media content with the content key.

14. The digital media device of claim 11, further comprising:

logic for requesting a release of the escrow key associated with the first processor from the key clearinghouse, the request including the identity of a second processor.

15. The digital media device of claim 14, wherein the logic for requesting a release of the escrow key associated with the first processor from the key clearinghouse is configured to cause the key clearinghouse to:

determine whether the second processor is authorized to access the escrow key; and

if the second processor is authorized to access the escrow key, decrypt the escrow key, encrypted with the public key of the key clearinghouse, with a private key of the key clearinghouse;

re-encrypt the escrow key with a public key of the second processor; and

deliver the escrow key, encrypted with the public key of the second processor, to the second processor.

16. The digital media device of claim 15, further comprising:

logic for decrypting the escrow key, encrypted with the public key of the second processor, with the private key of the second processor;

logic for decrypting the content key, encrypted with the escrow key, with the escrow key; and

logic for decrypting the instance of media content with the content key.

17. An access control system for managing encryption keys associated with digital media device comprising:

a first digital media device having a first processor, the first processor configured to;

generate an escrow key for encrypting a plurality of content keys for encrypting instances of media content;

encrypt the escrow key with a public key of a key clearinghouse; and

store the escrow key, encrypted with the public key of the key clearinghouse, in a storage location outside of the first processor of the media device; and

a key clearinghouse for providing conditional access to the escrow key by a second processor.

18. The access control system of claim 17, wherein the digital media device is further configured to:

encrypt an instance of media content to be stored on a first storage device of the media device with a content key;

encrypt the content key with the escrow key; and

store the content key, encrypted with the escrow key, to the first storage device.

19. The access control system of claim 18, wherein the digital media device is further configured to:

retrieve the content key, encrypted with the escrow key, from the storage device;

decrypt the content key, encrypted with the escrow key, with the escrow key; and

decrypt the media content with the content key.

20. The access control system of claim 18, further comprising:

a second media device having a second processor, the second media device configured to request a release of the escrow key associated with the first processor from the key clearinghouse, the request including the identity of a second processor.

21. The access control system of claim 20, wherein the key clearinghouse is configured, in response to receiving the request to release the escrow key associated with the first processor from the key clearinghouse, to:

determine whether the second processor is authorized to access the escrow key; and

if the second processor is authorized to access the escrow key, decrypt the escrow key, encrypted with the public key of the key clearinghouse, with a private key of the key clearinghouse;

re-encrypt the escrow key with a public key of the second processor; and

deliver the escrow key, encrypted with the public key of the second processor, to the second processor.

22. The access control system of claim 21, wherein the second processor is further configured to decrypt the escrow key, encrypted with the public key of the second processor, with the private key of the second processor, and decrypt the content key, encrypted with the escrow key, with the escrow key;

and

wherein the second media device is configured to decrypt the instance of media content with the content key.