Authorization of services in a conditional access system

• US 20030074565A1
• Filed: 11/05/2002
• Published: 04/17/2003
• Est. Priority Date: 04/03/1995
• Status: Active Grant

• Current Assignee: Tech 5 SAS
• Original Assignee: Anthony J. Wasilewski, Glendon L. Akins III, Howard G. Pinder, Robert O. Banker
• Inventors: Pinder, Howard G., Banker, Robert O., Wasilewski, Anthony J., Akins, Glendon L. III
• Granted Patent: US 6,971,008 B2
• Time in Patent Office: Days
• US Class Current: 713/182
• CPC Class Codes: H04J 2203/008 Support of video
• CPC Class Codes: H04L 2463/101 applying security measures for digital rights management data processing systems or methods, specially adapted for commerce, e.g. marketing, shopping, billing, auctions or e-commerce G06Q30/00
• CPC Class Codes: H04L 63/04 for providing a confidential data exchange among entities communicating through data packet networks
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/0442 wherein the sending and receiving network entities apply asymmetric encryption, i.e. different keys for encryption and decryption cryptographic mechanisms or cryptographic arrangements for public-key encryption H04L9/30
• CPC Class Codes: H04L 63/045 wherein the sending and receiving network entities apply hybrid encryption, i.e. combination of symmetric and asymmetric encryption cryptographic mechanisms or cryptographic arrangements using a plurality of keys or algorithms H04L9/14
• CPC Class Codes: H04L 63/062 for key distribution, e.g. centrally by trusted party cryptographic mechanisms or cryptographic arrangements for key distribution involving a central third party H04L9/0819
• CPC Class Codes: H04L 63/08 for authentication of entities cryptographic mechanisms or cryptographic arrangements for entity authentication H04L9/32
• CPC Class Codes: H04L 63/0823 using certificates cryptographic mechanisms or cryptographic arrangements for entity authentication involving certificates H04L9/3263
• CPC Class Codes: H04L 63/12 Applying verification of the received information cryptographic mechanisms or cryptographic arrangements for data integrity or data verification H04L9/32
• CPC Class Codes: H04L 63/123 received data contents, e.g. message integrity
• CPC Class Codes: H04N 21/2265 Server identification by a unique number or address, e.g. serial number network arrangements, protocols or services for addressing or naming H04L61/00
• CPC Class Codes: H04N 21/23476 by partially encrypting, e.g. encrypting the ending portion of a movie
• CPC Class Codes: H04N 21/26606 for generating or managing entitlement messages, e.g. Entitlement Control Message [ECM] or Entitlement Management Message [EMM] arrangements for conditional access to broadcast information or to broadcast-related services H04H60/14
• CPC Class Codes: H04N 21/426 Internal components of the client ; Characteristics thereof H04N5/44 takes precedence
• CPC Class Codes: H04N 21/4405 involving video stream decryption
• CPC Class Codes: H04N 21/4524 involving the geographical location of the client retrieval from the Internet by querying based on geographical locations G06F16/9537; systems specially adapted for using geographical information in broadcast systems H04H60/70; protocols in which the network application is adapted for the location of the user terminal in communication control or processing H04L67/52; services making use of the location of users or terminals in wireless networks H04W4/02; locating users or terminals in wireless networks H04W64/00
• CPC Class Codes: H04N 21/63345 by transmitting keys key distribution for secret or secure communication H04L9/08; network support of key management H04L63/06
• CPC Class Codes: H04N 7/162 Authorising the user terminal, e.g. by paying; Registering the use of a subscription channel, e.g. billing
• 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
• CPC Class Codes: H04N 7/17354 : in an intermediate station common to a plurality of user terminals

Abstract

A cable television system provides conditional access to services. The cable television system includes a headend from which service “instances”, or programs, are broadcast and a plurality of set top units for receiving the instances and selectively decrypting the instances for display to system subscribers. The service instances are encrypted using public and/or private keys provided by service providers or central authorization agents. Keys used by the set tops for selective decryption may also be public or private in nature, and such keys may be reassigned at different times to provide a cable television system in which piracy concerns are minimized.

Claims

1. A conditional access apparatus in a receiver for giving a receiver, in a cable television system, conditional access to a given encrypted instance of service of a plurality of encrypted instances of services received in the receiver, the conditional access apparatus comprising:

an agent establishment apparatus adapted to establish an entitlement agent in the receiver in response to a first message received in the receiver, wherein the agent establishment apparatus imposes constraints in the receiver on the established entitlement agent, and the established entitlement agent is associated with the given encrypted instance of service;

an entitlement specification apparatus in communication with the agent establishment apparatus, the entitlement specification apparatus adapted to specify the one or more service entitlements, wherein specified service entitlements include entitlements of the receiver for instances of services received in the receiver that are associated with the established entitlement agent; and

an access granting apparatus in communication with the entitlement specification apparatus, the access granting apparatus adapted to grant access to the given instance of service in response to a second message received in the receiver, the second message includes an entitlement identifier associated with the given encrypted instance of service, wherein the access granting apparatus uses the specified service entitlement and the entitlement identifier to grant access to the given instance of service, and the access granting apparatus grants access to the given instance of service only if the agent establishment apparatus has established the entitlement agent, and the given instance of service includes services including programming that are provided to the cable television system.

2. The conditional access apparatus of claim 1, wherein:

the constraints imposed on the established entitlement agent includes a limit for the entitlements the established entitlement agent may offer.

3. The conditional access apparatus of claim 2, wherein:

the limit limits the kinds of entitlements the established entitlement agent may offer.

4. The conditional access apparatus of claim 2, wherein:

the limit limits the number of entitlements the established entitlement agent may offer.

5. The conditional access apparatus of claim 2, wherein:

the entitlement specification apparatus specifies the one or more service entitlements within the limit established by the agent establishment apparatus.

6. The conditional access apparatus of claim 1, wherein:

the agent establishment apparatus further disestablishes the established entitlement agent, whereupon the access granting apparatus no longer grants access to an instance of service associated with the disestablished entitlement agent.

7. The conditional access apparatus of claim 1, wherein:

the agent establishment apparatus and the entitlement specification apparatus operate in response to further messages received in the receiver.

8. The conditional access apparatus of claim 7, wherein:

the agent establishment apparatus and the entitlement specification apparatus respond to the further messages without interruption to currently-granted access to the information.

9. The conditional access apparatus of claim 7, wherein:

the agent establishment apparatus and the entitlement specification apparatus include at least first and second keys, employ the at least first and second keys to determine whether a received message is authentic, and respond to the received message only if the received message is authentic.

10. The conditional access apparatus of claim 9, wherein:

the agent establishment apparatus, the entitlement specification apparatus, and the access granting apparatus are implemented in a secure element, which includes a processor and storage for the service entitlements and the keys, and the storage is writable and accessible only to the processor of the secure element.

11. The conditional apparatus of claim 9, wherein:

the further messages are encrypted; and

the conditional access apparatus includes another key and employs the other key to decrypt the further messages.

12. The conditional access apparatus of claim 11, wherein:

the receiver has a public key and a private key;

the further messages are encrypted with the public key; and

the private key is the other key.

13. The conditional access apparatus of claim 9, wherein:

the second message includes an authentication token that was processed by the private key of a private key-public key associated with the entitlement agent;

the access granting apparatus uses the authentication token with a public key of the established entitlement agent to determine whether the second message is authentic and grants access to the given instance of service only if the second message is authentic.

14. The conditional access apparatus of claim 1, wherein:

the receiver includes decryption apparatus for decrypting the instance of service;

the second message contains a decryption value;

the entitlement specification apparatus contains an additional key for the established entitlement agent;

the access granting apparatus employs the additional key and the decryption value to obtain a decryption key for the instance of service; and

the receiver uses the decryption key to decrypt the instance of service.

15. The conditional access apparatus of claim 14, wherein:

the additional key is a shared secret that the entitlement specification apparatus shares with the established entitlement agent; and

the access granting apparatus uses the shared secret to determine whether the second message is authentic and grants access to the instance of service only if the second message is authentic.

16. The conditional access apparatus of claim 7, wherein:

the agent establishment apparatus disestablishes the established entitlement agent in response to a third message of the further messages.

17. The conditional access apparatus of claim 16, wherein:

the agent establishment apparatus includes a first key representing a conditional access authority; and

the agent establishment apparatus employs the first key to determine whether the third message is authentic and disestablishes the established entitlement agent only if the third message is authentic.

18. The conditional access apparatus of claim 7, wherein:

the agent establishment apparatus establishes a new entitlement agent in response to a third message of the further messages.

19. The conditional access apparatus of claim 18, wherein:

the agent establishment apparatus includes a first key representing a conditional access authority; and

the agent establishment apparatus employs the first key to determine whether the third message is authentic and establishes the new entitlement agent only if the third message is authentic.

20. The conditional access apparatus of claim 7, wherein:

the entitlement specification apparatus specifies the given service entitlement in response to a fourth message of the further messages.

21. The conditional access apparatus of claim 20, wherein:

the entitlement specification apparatus includes a second key representing the entitlement agent; and

the entitlement specification apparatus employs, if the third message is authentic, the second key to determine whether the fourth message is authentic and, in response to determining that the fourth message is authentic, further specifies the given entitlement.

22. The conditional access apparatus of claim 7, wherein:

the agent establishment apparatus includes other keys representing a conditional access authority;

the agent establishment apparatus changes a first key of the plurality of keys in response to at least second and third messages of the further messages, the agent establishment apparatus using the other keys of the plurality of keys to determine whether the at least second and third messages are authentic and changing the other keys only when the at least second and third messages are authentic.

23. The conditional access apparatus of claim 22, wherein the agent establishment apparatus both establishes and disestablishes the conditional access authority in accordance with use of the other keys and authentication of the at least second and third messages.

24. The conditional access apparatus of claim 1, wherein:

the agent establishment apparatus, the entitlement specification apparatus, and the access granting apparatus are implemented in a secure element that includes storage for the entitlements and a processor, and wherein the storage is writable and accessible only to the processor of the secure element.

25. The conditional access apparatus of claim 1, wherein:

the agent establishing apparatus and the entitlement specification apparatus operate without interruption to currently-granted access to the instance of service.

26. The conditional access apparatus of claim 1, wherein all authentication is performed using RSA digital signatures.

27. The conditional access apparatus of claim 1, wherein the instance of service is a program from the set of programs consisting of video programs, audio programs and audio-video programs.

28. The conditional access apparatus of claim 1, wherein the instance of service is an MPEG program.

29. A method for providing a receiver, in a conditional access system, with an entitlement for an encrypted instance of service, wherein the instance of service is provided by a service provider to the conditional access system, the method comprising the steps of:

receiving at the receiver a first message, the first message having an indicator associated with an entitlement agent included therein;

processing in the receiver the first message to authenticate the first message and, to establish, in the receiver, the entitlement agent associated with the indicator of the first message, wherein only when the first message is authentic is the entitlement agent established, and the act of establishing the entitlement agent imposes constraints, in the receiver, on the established entitlement agent;

receiving at the receiver a second message, the second message having a service service entitlement specifier associated with the instance of service included therein;

processing the second message to associate the service entitlement specifier with the established entitlement agent;

receiving at the receiver the encrypted instance of service and a third message having an entitlement identifier included therein, wherein the entitlement identifier is associated with the instance of service; and

processing in the receiver the third message to determine whether the receiver is entitled to decrypt the encrypted instance of service.

30. The method of claim 29, wherein the entitlement agent is one of a plurality of entitlement agents that are associated with instances of services provided to the receiver, a conditional access authority assigns constraints that are imposed upon the established entitlement agent, the first message, which is from the conditional access authority, includes the constraints for the entitlement agent, and the act of establishing the entitlement agent includes imposing the constraints assigned by the conditional access authority on the established entitlement agent.

31. The method of claim 30, wherein the act of establishing includes the act of configuring at least a portion of the memory of receiver according to a predetermined configuration.

32. The method of claim 31, wherein the predetermined configuration of the receiver memory is determined by the conditional access authority, and the first message includes information related to the predetermined configuration.

33. The method of claim 29, wherein the act of determining further includes using at least the entitlement identifier and the service entitlement specifier to determine whether the receiver is entitled to decrypt the received encrypted instance of service.

34. The method of claim 29, wherein the receiver includes a memory, and the constraints imposed on the established entitlement agent includes allocating a maximum amount of the memory to the established entitlement agent.

35. The method of claim 29, wherein the constraints imposed on the established entitlement agent includes controlling the entitlements offered by the entitlement agent.

36. The method of claim 35, wherein controlling the entitlements includes act of limiting the number of entitlements offered by the established entitlement agent.

37. The method of claim 36, wherein controlling the entitlements includes the act of limiting the types of entitlements offered by the established entitlement agent.

38. The method of claim 29, further including the steps of:

receiving a fourth message having a second service entitlement specifier associated with the instance of service; and

processing the fourth message to associate the second service entitlement specifier with the established entitlement agent, wherein the second service entitlement specifier specifies that the receiver is not entitled to decrypt the received encrypted instance of service.

39. The method of claim 29, further including the step of:

receiving at the receiver a fourth message;

processing a fourth message to authenticate the fourth message and, only when the fourth message is authentic, to disestablish the established entitlement agent, whereupon the receiver is not entitled to decrypted the received encrypted instance of service.

40. The method of claim 39, wherein the receiver includes memory, the entitlement agent has a portion of the memory allocated thereto for the established entitlement agent, and the act of disestablishing the established entitlement agent includes allocating none of the memory to the entitlement agent.

41. The method of claim 29, wherein the act of establishing includes storing a public key of a private key-private key pair associated with the entitlement agent in a memory of the receiver.

42. The method of claim 41, wherein the memory of the receiver has a first and at least a second public key stored therein, each public key being half of public key-private key pair, the first public key is associated with a conditional access authority that authorizes the establishment of the entitlement agent in the receiver, the first public key is used to authenticate the first message, the second public key is associated with the entitlement agent and is included in the first message, the second public key is stored in the memory only if the first message is authentic, and the second public key is used to authenticate the second message.

43. The method of claim 42, further including the steps of:

receiving at the receiver a fourth message having encrypted content and an authentication token included therein;

using at least the authentication token of the fourth message to authenticate the source of the fourth message;

decrypting the encrypted content of the fourth only when the source of the fourth message has been authenticated, and wherein the decrypted content of the fourth message includes a long-term key;

using the long-term key and a portion of the fourth message to generate a short-term key; and

using the short term key to decrypt the encrypted instance of service only when the receiver is entitled to the instance of service.

44. The method of claim 43, wherein the memory of the receiver includes a private key of a public key-private key pair, and the receiver uses the private key to decrypt the encrypted content of the fourth message.

45. The method of claim 43, wherein the source of the fourth message is the entitlement agent.

46. The method of claim 29, wherein the receiver has a memory having a plurality of public keys associated a conditional access authority stored therein, wherein the conditional access authority authorizes the establishment of the entitlement agent, and each public key is part of a public key-private key pair, and further including the steps of:

receiving a fourth message at the receiver having a content that includes a particular public key, an authentication token and a key indicator included therein;

using a first public key of the plurality of public keys to authenticate the source of the fourth message;

associating the key indicator with a given public key of the plurality of keys associated with the conditional access authority;

replacing the given public key with the particular public key only when the conditional access authority is authenticated as the source of the third entitlement message.

47. The method of claim 46, further including the steps of:

using at least a portion of the content of the fourth message as an input into a hash function to produce an output hash;

comparing the output hash with a portion of the authentication token of the fourth message, and wherein the given key is replaced by the particular key only when the compared portion of the authentication token is the same as the output hash.

48. The method of claim 47, further including the steps of:

receiving a fifth message at the receiver having a content that includes a second particular public key, an authentication token and a second key indicator included therein, wherein the second particular public key is the same as the particular public key included in the fourth message, and the second key indicator is the same as the key indicator included in the fourth message;

using a second public key of the plurality of public keys to authenticate the source of the fifth message;

using at least a portion of the content of the fifth message as an input into a hash function to produce a second output hash;

comparing the second output hash with the first output hash, and wherein the given key is replaced by the particular key only when the second output hash is the same as the first output hash.

49. An entitling apparatus in a receiver, wherein the receiver is in a conditional access system and receives an encrypted instance of service, the instance of service is associated with an entitlement agent that is included in the conditional access system, the apparatus comprising:

means for establishing entitlements in the receiver for the entitlement agent, wherein the establishing means establishes the entitlements in response to a first message;

means for specifying service entitlements of the receiver, wherein the specifying means specifies the service entitlements of the receiver for the instances of service associated with the entitlement agent, and the service entitlements are specified in response to a second message;

means for granting the decryption of the received encrypted instance of service,

wherein the encrypted instance of service is associated with an entitlement identifier, and the granting is based at least in part on the entitlement identifier and at least in part on the specified service entitlement of the receiver for the instance of service.

50. The apparatus of claim 49, wherein the establishing means imposes constraints in the receiver on the entitlements for the entitlement agent.

51. The apparatus of claim 50, wherein the constraints in the receiver imposed on the entitlement agent include controlling the types of services associated with the entitlement agent.

52. The apparatus of claim 50, wherein the constraints in the receiver imposed on the entitlement agent include limiting the number of service entitlements.

53. The apparatus of claim 50, further including:

a memory, wherein at a portion of the memory is allocated to the entitlement agent, and the imposed constraints includes limiting the memory usage of the entitlement agent to the portion of the memory allocated to the entitlement agent.

54. The apparatus of claim 53, wherein in response to a third message the entitlement agent is allocated none of the memory of the receiver, and thereupon the receiver is not entitled to decrypted instances of service associated with the entitlement agent.

55. The apparatus of claim 53, wherein the memory has a public key of a public key-private key pair stored therein, wherein the public key is used to authenticate the first message, the first message includes a second public key that is associated with the entitlement agent, and when the first message is authentic the second public key is stored in portion of the memory allocated to the entitlement agent.

56. The apparatus of claim 55, wherein the second public key is used to authenticate the second message, and only when the second message is authentic are the service entitlements specified.

57. The apparatus of claim 55, further including:

means for generating a decryption key to generate a key for decrypting the encrypted instance of service, wherein the decryption key generating means uses at least a long-term key to generate a short-term decryption key for the decrypting the encrypted instance of service.

58. The apparatus of claim 57, wherein the long-term key is included in a third message, which is authenticated by the second public key, and only when the second message is authentic is the long-term key used by the decryption key generating means.

59. The apparatus of claim 58, wherein the receiver receives a fourth message that is associated with the encrypted instance of service, the fourth message includes the entitlement identifier and a short-term key indicator, wherein the decryption key generating means uses the short-term indicator to generate the short-term decryption key.

60. The apparatus of claim 59, wherein through the duration of the instance of service a plurality of different short term decryption keys are used for decrypting the encrypted instance of service.