Conditional access system

• US 5,796,829 A
• Filed: 06/24/1996
• Issued: 08/18/1998
• Est. Priority Date: 09/09/1994
• Status: Expired due to Fees

• Current Assignee: Titan (L3Harris Technologies, Inc.)
• Original Assignee: Titan (L3Harris Technologies, Inc.)
• Inventors: Newby, Charles F., Harding, Michael V.
• Primary Examiner(s): CANGIALOSI, SALVATORE A
• Application Number:
  US08/646,251
• Time in Patent Office: 785 Days
• Field of Search: 380/20, 380/21, 380/47
• US Class Current: 705/54
• CPC Class Codes: H04N 21/4181 for conditional access
• CPC Class Codes: H04N 21/43607 Interfacing a plurality of external cards, e.g. through a DVB Common Interface [DVB-CI]
• 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 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

An access control processor for a conditional access system in which encrypted information segments provided by a plurality of information service providers are encrypted for transmission in accordance with different conditional access processes respectively utilizing different algorithms for encrypting the information segments. The processor includes a decryptor in an information receiver by decrypting encrypted information segmets received by the information receiver by processing the received encrypted information segments with a session key used for encrypting the information segments in accordance with an algorithm utilized in one of said conditional access processes; and a conditional access controller in the information receiver for selectively enabling the decryptor to decrypt received information segments encrypted in accordance with any of said different conditional access processes by providing to the decryptor cryptographic information for defining the algorithm utilized in said one of said different conditional access processes for use by the decryptor to decrypt the received information segment encrypted in accordance with said algorithm. Algorithm-defining cryptographic information is downloaded from an information stream received by the information receiver. Transmission of the cryptographic information for enabling the conditional access controller to enable the decryptor to decrypt a selected information segment may be requested by the conditional access controller and downloaded to the conditional access controller from an information stream received by the information receiver. A message related to an authorization status of the information receiver is retrieved for display from a plurality of different possible authorization status messages within an information stream received by the information receiver. Computer readable storage media are so configured as to cause the access control processor to perform its various functions.

Claims

1. An access control processor for a conditional access system in which encrusted information segments provided by a plurality of information service providers are encrypted for transmission in accordance with different conditional access processes respectively utilizing different algorithms for encrypting the information segments, the processor comprising

a decryptor in an information receiver for decrypting encrypted information segments received by the information receiver by processing the received encrypted information segments with a session key used for encrypting the information segments in accordance with an algorithm utilized in one of said conditional access processes;

and

a conditional access controller in the information receiver for selectively enabling the decryptor to decrypt received information segments encrypted in accordance with any of said different conditional access processes by providing to the decryptor cryptographic information for defining the algorithm utilized in said one of said different conditional access processes for use by the decryptor to decrypt the received information segment encrypted in accordance with said algorithm.

2. A processor according to claim 1, wherein the conditional access controller includes

means for detecting within an information stream received by the information receiver cryptographic information for defining the algorithm used for encrypting information segments in accordance with said one of said different conditional access processes;

and

means for downloading the detected cryptographic information from said information stream.

3. A processor according to claim 1, wherein the conditional access controller includes a replaceable security element, such as a smart card, for providing cryptographic information for defining the algorithm.

4. A processor according to claim 1, wherein the conditional access controller includes a memory in the information receiver storing cryptographic information for defining said different algorithms respectively utilized in said different conditional access processes.

5. A processor according to claim 1, wherein the conditional access controller selectively provides the cryptographic information for defining the algorithm utilized in said one conditional access process to the decryptor in accordance with a signal identifying said one conditional access process as the conditional access process used for encrypting the received information segments.

6. A processor according to claim 1, wherein the conditional access controller comprises

means for processing an authorization signal related to a selected information segment provided by each of a plurality of said service providers to determine which of a plurality of different possible authorization statuses is applicable to the selected information segment provided by each of the service providers;

and

means for selecting for decryption in accordance with a predetermined priority based upon said status determinations the encrypted information segment provided by one of said service providers.

7. A processor according to claim 6, wherein the cryptographic information for defining the algorithm provided by the conditional access controller to the decryptor is provided in accordance with said selection of the selected encrypted information segment provided by said one service provider.

8. A processor according to claim 1 in combination with a demultiplexer in the information receiver, wherein the demultiplexer is adapted for demultiplexing a received combined signal containing encrypted information segments and entitlement messages;

wherein the decryptor is coupled to the demultiplexer for receiving the demultiplexed encrypted information segments for said decryption, and wherein the conditional access controller is coupled to the demultiplexer for receiving the demultiplexed entitlement messages for processing in order to so enable the decryptor.

9. A processor according to claim 1 in combination with a demultiplexer in the information receiver, wherein the decryptor is adapted for decrypting encrypted information segments in a received combined signal containing encrypted information segments and entitlement messages,

wherein the demultiplexer is coupled to the decryptor for demultiplexing the combined signal following said decryption of the encrypted information segments by the decryptor;

and

wherein the conditional access controller is coupled to the demultiplexer for receiving the demultiplexed entitlement messages for processing in order to so enable the decryptor.

10. A conditional access system in which encrypted information is provided by a plurality of information service providers in accordance with different conditional access processes respectively utilizing different algorithms for encrypting the information, comprising

encryption means for encrypting information segments for transmission in accordance with different conditional access processes respectively utilizing different algorithms for encrypting the information segments;

a decryptor in an information receiver for decrypting encrypted information segments received by the information receiver by processing the received encrypted information segments with a session key used for encrypting the information segments in accordance with an algorithm utilized in one of said conditional access processes; and

a conditional access controller in the information receiver for selectively enabling the decryptor to decrypt received information segments encrypted in accordance with any of said different conditional access processes by providing to the decryptor cryptographic information for defining the algorithm utilized in said one of said different conditional access processes for use by the decryptor to decrypt the received information segment encrypted in accordance with said algorithm.

11. A system according to claim 10, further comprising

means for requesting transmission to the information receiver of cryptographic information for defining the algorithm utilized in said one of said different conditional access processes;

means for responding to said request by transmitting the requested cryptographic information; and

means in the information receiver for downloading the transmitted cryptographic information.

12. A system according to claim 11, wherein the conditional access controller includes the means for downloading the transmitted cryptographic information, to wit:

means for detecting the transmitted cryptographic information within an information stream received by the information receiver and means for downloading the detected cryptographic information from said information stream.

13. A system according to claim 10, further comprising

means for requesting transmission to the information receiver of other cryptographic information used by the conditional access controller for enabling the decryptor to decrypt the information encrypted in accordance with one of said different conditional access processes;

means for responding to said request by transmitting the requested other cryptographic information; and

means in the information receiver for downloading the transmitted other cryptographic information.

14. A system according to claim 13, wherein the conditional access controller includes the means for downloading the transmitted other cryptographic information, to wit:

means for detecting the transmitted other cryptographic information within an information stream received by the information receiver and means for downloading the detected other cryptographic information from said information stream.

15. A system according to claim 13, wherein the other cryptographic information includes data for use in generating a session key for use by the decryptor for decrypting information segments encrypted in accordance with the algorithm utilized in said one of said different conditional access processes;

and

the conditional access controller includes means for processing the downloaded session key generation data to generate said session key.

16. A computer readable storage medium for use in an access control processor included in an information receiver of a conditional access system in which encrypted information segments provided by a plurality of information service providers are encrypted for transmission in accordance with different conditional access processes respectively utilizing different algorithms for encrypting the information segments, and including a decryptor for decrypting encrypted information segments received by the information receiver by processing the received encrypted information segments with a session key used for encrypting the information segments in accordance with an algorithm utilized in one of said conditional access processes;

and a conditional access controller,

wherein the storage medium is configured so as the cause the conditional access controller to selectively enable the decryptor to decrypt received information segments encrypted in accordance with any of said different conditional access processes, by providing to the decryptor cryptographic information for defining the algorithm utilized in said one of said different conditional access processes for use by the decryptor to decrypt the received information segment encrypted in accordance with said algorithm.

17. A storage medium according to claim 16, further configured so as to cause the conditional access controller to detect within an information stream received by the information receiver cryptographic information for defining the algorithm used for encrypting information segments in accordance with said one of said different conditional access processes and to download the detected cryptographic information from said information stream.

18. A conditional access method in which encrypted information is provided by a plurality of information service providers in accordance with different conditional access processes respectively utilizing different algorithms for encrypting the information, comprising the steps of:

(a) encrypting information segments for transmission in accordance with different conditional access processes respectively utilizing different algorithms for encrypting the information segments;

(b) using a decryptor in an information receiver to decrypt encrypted information segments received by the information receiver by processing the received encrypted information segments with a session key used for encrypting the information segments in accordance with an algorithm utilized in one of said conditional access processes; and

(c) in the information receiver, selectively enabling the decryptor to decrypt received information segments encrypted in accordance with any of said different conditional access processes by providing to the decryptor cryptographic information for defining the algorithm utilized in said one of said different conditional access processes for use by the decryptor to decrypt the received information segment encrypted in accordance with said algorithm.

19. A method according to claim 18, wherein step (c) comprises the steps of:

(d) detecting within an information stream received by the information receiver cryptographic information for defining the algorithm used for encrypting information segments in accordance with said one of said different conditional access processes; and

(e) downloading the detected cryptographic information from said information stream.

20. A method according to claim 18, wherein step (c) comprises the step of:

(d) providing the cryptographic information for defining the algorithm in accordance with a signal identifying said one conditional access process as the conditional access process used for encrypting the received information segments.

21. A method according to claim 18, wherein step (c) comprises the step of:

(d) providing the cryptographic information from a memory in the information receiver storing cryptographic information for defining said different algorithms respectively utilized in said different conditional access processes.

22. A method according to claim 18, further comprising the steps of:

(d) processing an authorization signal related to a selected information segment provided by each of a plurality of said service providers to determine which of a plurality of different possible authorization statuses is applicable to the selected information segment provided by each of the service providers, and

(e) selecting for decryption in accordance with a predetermined priority based upon said status determinations the encrypted information segment provided by one of said service providers.

23. A method according to claim 22, wherein step (c) comprises the step of:

(f) providing the cryptographic information for defining the algorithm to the decryptor in accordance with said selection of the encrypted information segment provided by said one service provider.

24. A method according to claim 18, further comprising the steps of:

(d) requesting transmission to the information receiver of cryptographic information for defining the algorithm utilized in said one of said different conditional access processes;

(e) responding to said request by transmitting the requested cryptographic information; and

(f) in the information receiver, downloading the transmitted cryptographic information.

25. A method according to claim 24, wherein step (f) includes the steps of

(g) detecting the transmitted cryptographic information within an information stream received by the information receiver;

and

(h) downloading the detected cryptographic information from said information stream.

26. A method according to claim 18, further comprising the steps of:

(d) requesting transmission to the information receiver of cryptographic information used for enabling decryption of the information encrypted in one of said different conditional access processes,

(e) responding to said request by transmitting the requested cryptographic information; and

(f) in the information receiver, downloading the transmitted cryptographic information.

27. A method according to claim 26, wherein step (f) includes the steps of:

(g) detecting the transmitted cryptographic information within an information stream received by the information receiver; and

(h) downloading the detected cryptographic information from said information stream.

28. A method according to claim 26, wherein the cryptographic information includes data for use in generating a session key for use by the decryptor for decrypting information segments encrypted in accordance with said one conditional access process.