Methods and apparatuses for providing DRM interoperability

• US 8,386,799 B2
• Filed: 12/03/2009
• Issued: 02/26/2013
• Est. Priority Date: 12/03/2008
• Status: Expired due to Fees

• Current Assignee: Postech Academy-Industry Foundation
• Original Assignee: Postech Academy-Industry Foundation
• Inventors: Kim, Jong, Lee, Sangho, Park, Heejin
• Primary Examiner(s): Chea, Philip
• Assistant Examiner(s): SHEHNI, GHAZAL B
• Application Number:
  US12/630,646
• Publication Number:
  US 20100138671A1
• Time in Patent Office: 1,181 Days
• Field of Search: 713185-189
• US Class Current: 713/189
• CPC Class Codes: G06F 21/1063 Personalisation

Abstract

Methods and apparatuses for providing DRM interoperability are provided. Proxy re-encryption technique using bilinear map is used, and the same content can be used in different devices. According to the method of providing DRM interoperability includes in proxy agent with respect to digital rights management (DRM) service providers and device which supports predetermined DRM, first DRM service provider, second DRM service provider, the proxy agent, and the device identify each other, and proxy re-encrypt an interoperable content (IC) and provide the IC to the device. The IC is second-level encrypted by using a key of the first DRM service provider, and the proxy re-encryption is performed by using a proxy key generated from proxy key information provided from the first DRM service provider and the second DRM service provider. Therefore, a problem in which interoperability cannot be guaranteed since a DRM technique depends on a service provider is resolved.

Claims

1. A method of providing digital rights management (DRM) interoperability in a proxy agent with respect to a plurality of DRM service providers and a device which supports a predetermined DRM, comprising:

at a first DRM service provider having keys EK₁ and EK₂, a second DRM service provider having a key CEK_A, the proxy agent, and the device, identifying each other; and

proxy re-encrypting an interoperable content (IC) provided from the first DRM service provider and providing the IC to the device,

wherein the IC comprises a key K_M that is second-level encrypted using keys EK₁ and EK₂ of the first DRM service provider,

wherein proxy re-encryption is performed by using a proxy key generated from proxy key information provided from the first DRM service provider and the second DRM service provider to provide DRM interoperability between different devices,

wherein second-level encryption refers to an encryption technique which is performed in advance in order to perform the proxy re-encryption later,

wherein proxy re-encrypting a second-level encrypted content generates a first-level encrypted content, and

wherein proxy re-encrypting is expressed PRE_PRoxYKEY(PRE2_EK1,EK2(K_M))=PRE1_CEKA(K_M).

2. The method of claim 1, wherein the identifying of each other comprises:

at the device, providing the proxy agent with a device identifier and a DRM identifier supported by the device; and

at the proxy agent, providing the first DRM service provider and the second DRM service provider with the device identifier and a proxy agent identifier.

3. The method of claim 1, wherein the IC further comprises an encrypted content and a license.

4. The method of claim 3, wherein the IC further comprises at least one of a content identifier, a content creator, a content name, and a content replay type.

5. The method of claim 4, wherein the license includes the key EK₂ used to second-level encrypt the key K_M.

6. The method of claim 5, wherein the key EK₂ included in the license is encrypted by a public key or a secret key of the proxy agent.

7. The method of claim 1, wherein the first DRM service provider is a content management server, and the device is a handheld device.

8. The method of claim 1, wherein the identifying of each other comprises at the first DRM service provider, the second DRM service provider, the proxy agent, and the device, identifying each other, and the proxy re-encrypting of the interoperable content (IC) comprises:

receiving an IC including a second-level encrypted key K_M by using the keys EK₁ and EK₂ of the first DRM service provider from the first DRM service provider;

receiving proxy key information from the first DRM service provider and the second service provider through a key generation center;

generating the proxy key using the proxy key information;

proxy re-encrypt the second-level encrypted key K_M included in the IC by using the proxy key to generate a first-level encrypted key K_M; and

providing the device with the IC including the first-level encrypted key K_M.

9. The method of claim 8, wherein the identifying of each other comprises at the first DRM service provider, providing the key generation center with the device identifier, a DRM identifier supported by the first DRM service provider, and a proxy agent identifier.

10. The method of claim 8, further comprising, providing the device with the key CEK_A used to decrypt the first-level encrypted key K_M from the second DRM service provider.

11. An apparatus of providing digital rights management (DRM) interoperability with respect to a plurality of DRM service providers and a device which supports a predetermined DRM, comprising:

at least one processor which identifies a first DRM service provider having keys EK₁ and EK₂, a second DRM service provider having a key CEK_A, and the device and is identified by the first DRM service provider, the second DRM service provider, and the device, proxy re-encrypts an interoperable content (IC) provided from the first DRM service provider and provides the IC to the device; and

a memory connected with the processor to store the IC,

wherein the IC comprises key K_M that is second-level encrypted using the keys EK₁ and EK₂ of the first DRM service provider,

wherein the processors performs the proxy re-encryption by using a proxy key generated from proxy key information provided from the first DRM service provider and the second DRM service provider to provide DRM interoperability between different devices,

wherein the second-level encryption refers to an encryption technique which is performed in advance in order to perform the proxy re-encryption later,

wherein proxy re-encrypting a second-level encrypted content generates a first-level encrypted content, and

wherein proxy re-encrypting is expressed as PRE_PROXYKEY(PRE2_EK1,EK2(K_M))=PRE1_CEKA(K_M).

12. The apparatus of claim 11, wherein the processor receives a device identifier and a DRM identifier supported by the device from the device and provides the device identifier and a proxy agent identifier to the first DRM service provider and the second DRM service provider.

13. The apparatus of claim 11, wherein the IC further comprises an encrypted content and a license.

14. The apparatus of claim 13, wherein the IC further comprises at least one of a content identifier, a content creator, a content name, and a content replay type.

15. The apparatus of claim 14, wherein the license includes the key EK₂ used to second-level encrypt the key K_M.

16. The apparatus of claim 15, wherein the key EK₂ included in the license is encrypted by a public key or a secret key of the proxy agent.

17. The apparatus of claim 11, wherein the processor identifies the first DRM service provider, the second DRM service provider, a key generation center, and the device and is identified by the first DRM service provider, the second DRM service provider, a key generation center, and the device

receiving an IC including a second-level encrypted key K_M by using keys EK₁ and EK₂ of the first DRM service provider from the first DRM service provider;

receiving proxy key information from the first DRM service provider and the second service provider through a key generation center;

generating the proxy key using the proxy key information;

proxy re-encrypting the second-level encrypted key K_M included in the IC by using the proxy key to generate a first-level encrypted key K_M; and

providing the device with the IC including the first-level encrypted key K_M.

18. The apparatus of claim 17, wherein the first DRM service provider provides the key generation center with the device identifier, a DRM identifier supported by the first DRM service provider, and a proxy agent identifier.

19. The apparatus of claim 17, wherein the second DRM service provider provides the device with the key CEK_A used to decrypt the first-level encrypted key K_M.