Content protection key encryptor for security providers

• US 8,837,726 B2
• Filed: 10/16/2009
• Issued: 09/16/2014
• Est. Priority Date: 10/16/2009
• Status: Expired due to Fees

• Current Assignee: Tech 5 SAS
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Pinder, Howard G.
• Primary Examiner(s): Rahman, Mohammad L
• Assistant Examiner(s): CHANG, KENNETH W
• Application Number:
  US12/580,589
• Publication Number:
  US 20110091037A1
• Time in Patent Office: 1,796 Days
• Field of Search: 380/255
• US Class Current: 380/255
• CPC Class Codes: H04L 2209/60 Digital content management, e.g. content distribution
• CPC Class Codes: H04L 9/0822 using key encryption key
• CPC Class Codes: H04L 9/083 involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP]
• CPC Class Codes: H04L 9/0897 involving additional devices, e.g. trusted platform module [TPM], smartcard or USB

Abstract

Techniques are provided to receive at an encryption device from a control device an encryption request comprising a message and an identifier for a device. The control device and the device are associated with a security provider that provides secure content to the device using the message encrypted with a device key that is securely embedded in the device and also stored on the encryption device. The encryption device is associated with a key provider and the device key is not divulged to the security provider. At the encryption device, the device key is retrieved based on the identifier. The message is encrypted with the device key using a predetermined algorithm, and the encrypted message is then sent to the control device.

Claims

1. A method comprising:

receiving at an encryption device from a control device an encryption request comprising a content protection key (CPK) to be encrypted and an identifier for a decryption device, wherein the control device is controlled by a security provider that provides secure content to the decryption device using the CPK encrypted with a device key that is securely embedded in the decryption device and also stored on the encryption device, wherein the encryption device is provided by a key provider and the device key is not divulged to the security provider in order to prevent a compromise of the device key, and wherein the secure content is secured by encrypting content using a control word that itself is encrypted by the CPK;

retrieving at the encryption device the device key based on the decryption device identifier;

encrypting the CPK with the device key using a predetermined algorithm; and

sending the encrypted CPK to the control device.

2. The method of claim 1, wherein the predetermined algorithm is supplied by the security provider.

3. The method of claim 1, wherein encrypting comprises encrypting the CPK with the device key using a secure hardware module within the encryption device provided by the security provider, and wherein the predetermined algorithm is embedded in the secure hardware module.

4. The method of claim 1, wherein the predetermined algorithm comprises a plurality of encryption algorithms agreed upon by the security provider and the key provider, and further comprising selecting one of the plurality of encryption algorithms to encrypt the CPK.

5. The method of claim 1, wherein the device key is programmed into a secure one-time programmable memory of the decryption device during manufacture.

6. The method of claim 1, further comprising applying a predetermined transformation to the CPK prior to encrypting the CPK.

7. The method of claim 1, further comprising:

encrypting a control word with the CPK; and

encrypting a service intended for the decryption device with the control word.

8. The method of claim 1, wherein the CPK is used to encrypt services in a cable system and further comprising:

encrypting a control word with the CPK at a headend facility; and

encrypting a service intended for the decryption device with the control word, wherein the decryption device is a digital transport adapter.

9. An apparatus comprising:

a storage device configured to securely store device identifiers and corresponding device keys;

an interface configured to communicate with a control device that is controlled by a security provider that provides secure content to a decryption device using a content protection key (CPK) encrypted with a device key that is securely embedded in the decryption device and stored on the storage device;

a processor configured to;

receive an encryption request from the control device comprising the CPK to be encrypted and an identifier for the decryption device, wherein the apparatus is provided by a key provider and the device key is not divulged to the security provider in order to prevent a compromise of the device key, and wherein the secure content is secured by encrypting content using a control word that itself is encrypted by the CPK;

retrieve the device key from the storage device corresponding to the identifier;

encrypt the CPK with the device key using a predetermined algorithm; and

send the encrypted CPK to the control device.

10. The apparatus of claim 9, wherein the processor is configured to encrypt the CPK using the predetermined algorithm that is supplied by the security provider.

11. The apparatus of claim 9, wherein the processor is configured to encrypt the CPK using a secure hardware module provided by the security provider, and wherein the predetermined algorithm is embedded in the secure hardware module.

12. The apparatus of claim 9, wherein the processor is configured to encrypt the CPK using a plurality of predetermined encryption algorithms agreed upon by the security provider and the key provider, and wherein the processor is further configured to select one of the plurality of encryption algorithms to encrypt the CPK.

13. A system comprising the apparatus of claim 9, and further comprising the decryption device, wherein the device key is programmed into a secure one-time programmable memory of the decryption device during manufacture.

14. A system comprising the apparatus of claim 9, and further comprising the control device, wherein the control device is configured to apply a predetermined transformation to the CPK prior to encrypting the CPK.

15. A system comprising the apparatus of claim 9, and further comprising the control device, wherein the control device is configured to:

encrypt a control word with the CPK; and

direct that a service intended for the decryption device be encrypted with the control word.

16. A system comprising the apparatus of claim 9, and further comprising the control device residing in a cable system headend facility and the decryption device comprising a digital transport adapter (DTA), wherein the control device is configured to:

encrypt a control word with the CPK; and

direct that a service intended for the DTA be encrypted with the control word.

17. A non-transitory processor readable tangible medium encoded with instructions that, when executed by a processor, cause the processor to:

receive at an encryption device from a control device an encryption request comprising a content protection key (CPK) to be encrypted and an identifier for a decryption device, wherein the control device is controlled by a security provider that provides secure content to the decryption device using the CPK encrypted with a device key that is securely embedded in the decryption device and also stored on the encryption device, wherein the encryption device is provided by a key provider, and the device key is not divulged to the security provider in order to prevent a compromise of the device key, and wherein the secure content is secured by encrypting content using a control word that itself is encrypted by the CPK;

retrieve at the encryption device the device key based on the decryption device identifier;

encrypt the CPK with the device key using a predetermined algorithm; and

send the encrypted CPK to the control device.

18. The non-transitory processor readable tangible medium of claim 17, wherein the predetermined algorithm is supplied by the security provider.

19. The non-transitory processor readable tangible medium of claim 17, wherein the instructions that encrypt comprise instructions that cause the processor to encrypt using a secure hardware module within the encryption device provided by the security provider, and wherein the predetermined algorithm is embedded in the secure hardware module.

20. The non-transitory processor readable tangible medium of claim 17, wherein the predetermined algorithm comprises a plurality of encryption algorithms agreed upon by the security provider and the key provider, and further encoded with instructions that, when executed by a processor, cause the processor to select one of the plurality of encryption algorithms to encrypt the CPK.