Method and apparatus for controlling paired operation of a conditional access module and an integrated receiver and decoder

• US 7,797,552 B2
• Filed: 09/20/2002
• Issued: 09/14/2010
• Est. Priority Date: 09/21/2001
• Status: Active Grant

• Current Assignee: DIRECTV, LLC (AT&T, Inc.)
• Original Assignee: The DIRECTV Group, Inc. (AT&T, Inc.), NDS Group Limited (Cisco Systems, Inc.)
• Inventors: Levy, Jordan, Kahn, Raynold
• Primary Examiner(s): Moazzami; Nasser
• Assistant Examiner(s): McNally; Michael S
• Application Number:
  US10/490,261
• Publication Number:
  US 20050005120A1
• Time in Patent Office: 2,916 Days
• Field of Search: 713/193
• US Class Current: 713/193
• 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 21/4181 for conditional access
• CPC Class Codes: H04N 21/4367 Establishing a secure communication between the client and a peripheral device or smart card
• CPC Class Codes: H04N 21/4405 involving video stream decryption
• CPC Class Codes: H04N 21/4623 Processing of entitlement messages, e.g. ECM [Entitlement Control Message] or EMM [Entitlement Management Message] arrangements for conditional access to broadcast information or to broadcast-related services H04H60/14
• CPC Class Codes: H04N 21/47211 for requesting pay-per-view content payment schemes payment architectures or payment protocols G06Q20/00, G07F
• CPC Class Codes: H04N 21/6143 involving transmission via a satellite
• CPC Class Codes: H04N 21/6187 involving transmission via a telephone network, e.g. POTS
• CPC Class Codes: H04N 7/163 by receiver means only
• CPC Class Codes: H04N 7/1675 Providing digital key or authorisation information for generation or regeneration of the scrambling sequence pseudo-random number generators in general G06F7/58

Abstract

A method and apparatus that selectively pairs a receiver (132) configured to receive a media program encrypted according to a media encryption key and a conditional access module. In one embodiment, the apparatus comprises a security module (508) for receiving and modifying the media encryption key, and a transport module (412), comprising a decryptor (524) for decrypting the media program. The media encryption key has a portion indicating a first state in which the media program is to be viewable by a set of receivers or a second state in which the media program is to be viewable only by a subset of the set of receivers.

Claims

1. A method of selectively configuring a receiver of a set of receivers to receive a media program encrypted according to a media encryption key and a conditional access module, comprising the steps of:

receiving a media program in the receiver, the media program encrypted by either a media encryption key or a modified media encryption key;

receiving the media encryption key in the receiver, the media encryption key including a first portion indicating a first state in which the media program is to be viewable by a set of receivers or a second state in which the media program is to be viewable only by a subset of the set of receivers;

decrypting the media program in the receiver according to the media encryption key if the first portion indicates the first state; and

modifying the media encryption key in the receiver according to a second key stored by only the subset of the set of receivers to produce a modified media encryption key and decrypting the media program according to the modified media encryption key if the first portion indicates the second state.

2. The method of claim 1, wherein the second key is a pairing key and wherein:

the received media encryption key is encrypted by a conditional access module communicatively coupled to the receiver according to the pairing key before being received by the receiver;

the method further comprises the step of decrypting the media encryption key according to the pairing key in the receiver to produce a decrypted media encryption key;

the step of decrypting the media program according to the media encryption key if the first portion indicates the first state comprises the step of decrypting the media program according to the decrypted media encryption key if the first portion indicates the first state; and

the step of modifying the media encryption key to produce the modified media encryption key and decrypting the media program according to the modified media encryption key if the portion indicates the second state comprises the step of modifying the decrypted media encryption key to produce the modified media encryption key and decrypting the media program according to the modified media encryption key if the first portion indicates the second state.

3. The method of claim 2, wherein the first portion is a flag.

4. The method of claim 3, wherein:

the media encryption key is received in a security module;

the media program is decrypted in a transport module including a memory cache; and

the decrypted media encryption key is provided from the security module to the transport module only by direct memory access the memory cache.

5. The method of claim 2, wherein the pairing key comprises a pairing epoch and a pairing mask, and the step of modifying the decrypted media encryption key comprises the step of:

replacing at least a second portion of the media encryption key with the pairing epoch, wherein the at least a second portion of the media encryption key to be replaced by the pairing epoch is defined by the pairing mask.

6. The method of claim 5, further comprising the steps of:

receiving a second pairing key, the second pairing key including an incremented pairing epoch; and

replacing at least a third portion of the media encryption key with the second pairing epoch.

7. The method of claim 6, wherein the second pairing key further comprises a second pairing mask, and the at least a second portion of the media encryption key to be replaced with the incremented pairing epoch is defined according to the second pairing mask.

8. The method of claim 2, further comprising the steps of:

receiving the pairing key encrypted according to an I/O indecipherable algorithm;

decrypting the pairing key according to the I/O indecipherable algorithm;

storing the pairing key in the conditional access module; and

securely transmitting the pairing key in the receiver.

9. A method of selectively pairing a receiver configured to receive a media program encrypted according to a media encryption key and a conditional access module, comprising the steps of:

transmitting the media encryption key to the receiver via the conditional access module, the media encryption key including a first portion indicating a first state in which the media program is to be viewable by using a set of receivers or a second state in which the media program is to be viewable only by a subset of the set of receivers;

transmitting a pairing key to the conditional access module and to the receiver via the conditional access module;

wherein the media encryption key is encrypted in the conditional access module according to the pairing key before being provided to the receiver and decrypted in the receiver according to the pairing key;

wherein the transmitted pairing key comprises a pairing epoch and a pairing mask, the pairing key being encrypted according to an indecipherable algorithm implemented in the conditional access module; and

transmitting the media program encrypted according to the media encryption key;

wherein the first state commands the receiver to decrypt the media program according to the media encryption key, and the second state commands the receiver to modify the media encryption key and decrypt the media program according to the modified media encryption key; and

wherein the media encryption key is modified by replacing at least a second portion of the media encryption key with the pairing epoch, the at least a portion of the media encryption key to be replaced being defined by the pairing mask.

10. The method of claim 9, wherein the first portion is a flag.

11. The method of claim 9, further comprising the steps of:

transmitting a second pairing key including an incremented pairing epoch.

12. The method of claim 11, wherein the second pairing key further comprises a second pairing mask, and the at least a second portion of the media encryption key to be replaced with the incremented pairing epoch is defined according to the second pairing mask.

13. A receiver, configurable to selectively receive a media program, the receiver being one of a set of receivers, comprising:

means for receiving a media program encrypted by either a media encryption key or a modified media encryption key;

means for receiving the media encryption key, the media encryption key including a first portion indicating a first state in which the media program is to be viewable by a set of receivers or a second state in which the media program is to be viewable only by a subset of the set of receivers;

means for decrypting the media program according to the media encryption key if the first portion indicates the first state; and

means for modifying the media encryption key according to a second key stored by only a subset of the set of receivers to produce a modified media encryption key and decrypting the media program according to the modified media encryption key if the first portion indicates the second state.

14. The receiver of claim 13, wherein the second key is a pairing key and wherein:

the received media encryption key is encrypted by a conditional access module communicatively coupled to the receiver according to the pairing key before being received;

the receiver further comprises means for decrypting the media encryption key according to the pairing key to produce a decrypted pairing key;

the means for decrypting the media program according to the media encryption key if the first portion indicates the first state comprises means for decrypting the media program according to the decrypted media encryption key if the first portion indicates the first state; and

the means for modifying the media encryption key to produce the modified media encryption key and decrypting the media program according to the modified media encryption key if the first portion indicates the second state comprises means for modifying the decrypted media encryption key to produce the modified media encryption key and decrypting the media program according to the modified media encryption key if the first portion indicates the second state.

15. The receiver of claim 14, wherein the first portion is a flag.

16. The receiver of claim 14, wherein the pairing key comprises a pairing epoch and a pairing mask, and the means for modifying the decrypted media encryption key comprises:

means for replacing at least a second portion of the media encryption key with the pairing epoch, wherein the at least a second portion of the media encryption key to be replaced by the pairing epoch is defined by the pairing mask.

17. The receiver of claim 16, further comprising:

means for receiving a second pairing key, the second pairing key including an incremented pairing epoch; and

means for replacing at least a third portion of the media encryption key with the second pairing epoch.

18. The receiver of claim 17, wherein the second pairing key further comprises a second pairing mask, and the at least a third portion of the media encryption key to be replaced with the incremented pairing epoch is defined according to the second pairing mask.

19. The receiver of claim 16, wherein:

the media encryption key is received in a security module;

the media program is decrypted in a transport module including a memory cache; and

the decrypted media encryption key is provided from the security module to the transport module only by direct memory access the memory cache.

20. The receiver of claim 14, further comprising:

means for receiving the pairing key encrypted according to an I/O indecipherable algorithm;

means for decrypting the pairing key according to the I/O indecipherable algorithm;

means for storing the pairing key in the conditional access module; and

means for securely transmitting the pairing key in the receiver.

21. A receiver configurable to receive a media program encrypted according to a media encryption key if the media program is to be viewable by a set of receivers and according to a modified encryption key if the media program is to be viewable by a subset of the set of receivers, comprising:

means for transmitting a media encryption key to the receiver via the conditional access module, the media encryption key including a first portion indicating a first state in which the media program is to be viewable using all receivers or a second state in which the media program is to be viewable using only receivers paired with the conditional access module;

means for transmitting a pairing key to the conditional access module and to the receiver via the conditional access module only if the receiver is one of the subset of the set of receivers, wherein the transmitted pairing key comprises a pairing epoch and a pairing mask, the pairing key being encrypted according to an indecipherable algorithm implemented in the conditional access module; and

means for transmitting the media program encrypted according to the media encryption key;

wherein the first state commands the receiver to decrypt the media program according to the media encryption key, and the second state commands the receiver to modify the media encryption key and decrypt the media program according to the modified media encryption key; and

wherein the media encryption key is modified by replacing at least a second portion of the media encryption key with the pairing epoch, the at least a second portion of the media encryption key to be replaced being defined by the pairing mask.

22. The receiver of claim 21, wherein the first portion is a pairing flag.

23. The receiver of claim 21, further comprising:

means for transmitting a second pairing key including an incremented pairing epoch.

24. The receiver of claim 23, wherein the second pairing key further comprises a second pairing mask, and a third portion of the media encryption key is replaced with the incremented pairing epoch as defined according to the second pairing mask.

25. An receiver, configurable to selectively receive a media program encrypted according to a media encryption key if the media program is to be viewable by a set of receivers and according to a modified media encryption key if the media program is to be viewable by a subset of the set of receivers, comprising:

a security module, for receiving a media encryption key from the conditional access module, wherein the media encryption key has a first portion indicating a first state in which the media program is to be viewable by a set of receivers or a second state in which the media program is to be viewable only by a subset of the set of receivers, the security module including;

a module for modifying the media encryption key according to a second key stored only by the subset of receivers to produce a modified media encryption key if the first portion indicates the second state; and

a transport module, comprising a decryptor for decrypting the media program according to the media encryption key if the first portion indicates the first state and for decrypting the media program according to a modified media encryption key if the first portion indicates the second state.

26. The receiver of claim 25, wherein the second key is a pairing key and wherein:

the received media encryption key is encrypted by a conditional access module communicatively coupled to the receiver according to the pairing key before being received by the receiver; and

the security module further comprises a decryptor for decrypting the encrypted media encryption key according to the pairing key to produce a decrypted media encryption key.

27. The receiver of claim 26, wherein the first portion is a flag.

28. The receiver of claim 26, wherein the pairing key comprises a pairing epoch and a pairing mask, and the module for modifying the decrypted media encryption key comprises:

means for replacing at least a second portion of the media encryption key with the pairing epoch, wherein the at least a second portion of the media encryption key to be replaced by the pairing epoch is defined by the pairing mask.

29. The receiver of claim 28, wherein:

the receiver further receives a second pairing key, the second pairing key including an incremented pairing epoch; and

the security module further replaces at least a third portion of the media encryption key with the second pairing epoch.

30. The receiver of claim 29, wherein the second pairing key further comprises a second pairing mask, and the third portion of the media encryption key to be replaced with the incremented pairing epoch is defined according to the second pairing mask.

31. The receiver of claim 26, further comprising:

a means for receiving the pairing key encrypted according to an I/O indecipherable algorithm and for providing the encrypted pairing key to the conditional access module; and

a conditional access module for decrypting the pairing key according to the I/O indecipherable algorithm, for storing the pairing key therein and for transmitting the pairing key to the receiver.

32. The receiver of claim 26, wherein:

the transport module includes a memory cache; and

the decrypted media encryption key is provided from the security module to the transport module only by direct memory access the memory cache.

33. An apparatus for selectively commanding a receiver of a set of receivers to receive a media program encrypted according to a media encryption key if the media program is to be viewable by the set of receivers and encrypted according to a modified encryption key if the media program is to be viewable by only a subset of the set of receivers, comprising:

a transmitter for transmitting a media encryption key, wherein;

the media encryption key is encrypted according to an I/O indecipherable algorithm implemented in the conditional access module; and

the media encryption key includes a first portion indicating a first state in which the media program is to be viewable by a set of receivers or a second state in which the media program is to be viewable only by a subset of the set of receivers.

34. The apparatus of claim 33, wherein the transmitter further transmits a second key encrypted according to the I/O indecipherable algorithm.

35. The apparatus of claim 34, wherein the first portion is a flag.

36. The apparatus of claim 34, wherein:

the second key is transmitted the conditional access module and to the receiver via the conditional access module; and

the media encryption key is transmitted to the receiver via the conditional access module.

37. The apparatus of claim 34, wherein the second key is a pairing key stored only by the subset of the set of receivers and wherein:

the apparatus further comprises;

a conditional access module for receiving the media encryption key, decrypting the media encryption key re-encrypting the media encryption key according to the pairing key;

a receiver for receiving the re-encrypted media encryption key and for decrypting the re-encrypted media encryption key according to the pairing key; and

the first state commands the receiver to decrypt the media program according to the media encryption key; and

the second state commands the receiver to modify the decrypted media encryption key according to the pairing key and decrypt the media program according to the modified media encryption key.

38. The apparatus of claim 37, wherein:

the pairing key comprises a pairing epoch and a pairing mask; and

the second state commands the receiver to modify the decrypted media encryption key by replacing at least a second portion of the media encryption key with the pairing epoch, wherein the at least a second portion of the media encryption key to be replaced by the pairing epoch is defined by the pairing mask.

39. The apparatus of claim 38, wherein the transmitter further transmits a second pairing key encrypted according to the indecipherable algorithm implemented in the conditional access module, the second pairing key comprising an incremented pairing epoch.

40. The apparatus of claim 39, wherein the second pairing key further comprises a second pairing mask, and a third portion of the media encryption key is replaced with the incremented pairing epoch as defined according to the second pairing mask.