SIGNAL SECURITY IN A SATELLITE SIGNAL DISTRIBUTION ENVIRONMENT

• US 20110013774A1
• Filed: 12/21/2009
• Published: 01/20/2011
• Est. Priority Date: 07/20/2009
• Status: Active Grant

• Current Assignee: BCE Incorporated
• Original Assignee: BCE Incorporated
• Inventors: Dinesen, Tim, Ishankov, Alexander, Popa, Ovidiu Octavian, Scrivens, Wayne, Dagenais, Alan, Marusich, Peter
• Granted Patent: US 8,953,802 B2
• Time in Patent Office: Days
• US Class Current: 380/259
• CPC Class Codes: H04L 2209/60 Digital content management, e.g. content distribution
• CPC Class Codes: H04L 9/0825 using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates
• 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 21/6143 involving transmission via a satellite
• CPC Class Codes: H04N 5/913 for scrambling ; for copy protection
• CPC Class Codes: H04N 7/162 Authorising the user terminal, e.g. by paying; Registering the use of a subscription channel, e.g. billing

Abstract

Certain embodiments provide a set top box, comprising: a processing entity configured to obtain data for a channel stacking switch, to obtain a security data element and to formulate a message for the channel stacking switch by combining the security data element with the data; a communications interface configured to send the message to channel stacking switch. Other embodiments provide a channel stacking switch, comprising: a communication interface configured to receive a message from a set top box; a processing entity configured to determine whether or not the message is legitimate and to take an action that depends on whether or not the message is legitimate. Still further embodiments provide a satellite signal receiving system comprising a channel stacking switch and at least one set top box in secure communication with the channel stacking switch.

Claims

1. A method implemented by a set top box, the method comprising:

obtaining a security data element;

obtaining data for a channel stacking switch;

combining the security data element with the data to formulate a message for the channel stacking switch;

releasing the message towards the channel stacking switch.

2. The method defined in claim 1, wherein obtaining the security data element comprises retrieving the security data element from a memory.

3. The method defined in claim 1, wherein obtaining the security data element comprises receiving the security data element from the channel stacking switch.

4. The method defined in claim 3, wherein receiving the security data element from the channel stacking switch occurs in response to sending to the channel stacking switch a request for the security data element.

5. The method defined in claim 3, wherein the security data element is received in an encrypted form, the method further comprising extracting the security data element by way of decryption using a decryption key.

6. The method defined in claim 5, wherein the decryption key is a private key of the set top box.

7. The method defined in claim 1, wherein obtaining the security data element comprises receiving an index from the channel stacking switch and consulting a memory on a basis of the index in order to retrieve from the memory a data element associated with the index, the data element being the security data element.

8. The method defined in claim 1, further comprising obtaining a trigger, wherein obtaining the security data element is performed in response to the trigger.

9. The method defined in claim 8, wherein obtaining the trigger comprises receiving the trigger from the channel stacking switch.

10. The method defined in claim 9, wherein the trigger is received by the channel stacking switch over a satellite link from a head end unit.

11. The method defined in claim 8, wherein obtaining the trigger comprises receiving a command from a viewer of a display set connected to the set top box.

12. The method defined in claim 8, wherein the trigger is generated by the set top box.

13. The method defined in claim 1, wherein combining the security data element with the data to formulate the message comprises including the security data element in the message together with the data.

14. The method defined in claim 13, wherein the security data element comprises an identifier of the set top box.

15. The method defined in claim 1, wherein combining the security data element with the data to formulate the message comprises encrypting the data with the security data element.

16. The method defined in claim 15, wherein the security data element is a symmetric encryption key.

17. The method defined in claim 16, wherein the symmetric encryption key comprises an identifier of the channel stacking switch.

18. The method defined in claim 15, wherein the security data element is an asymmetric encryption key.

19. The method defined in claim 18, wherein the asymmetric encryption key is a public key of the channel stacking switch.

20. A set top box, comprising:

a processing entity configured to obtain data for a channel stacking switch, to obtain a security data element and to formulate a message for the channel stacking switch by combining the security data element with the data;

a communications interface configured to send the message to channel stacking switch.

21. A computer-readable storage medium storing instructions for execution by a set top box (STB), wherein execution of the instructions by the STB causes the STB to:

obtain a security data element;

obtain data for a channel stacking switch;

combine the security data element with the data to formulate a message for the channel stacking switch;

release the message towards the channel stacking switch.

22. A method implemented by a channel stacking switch (CSS), comprising:

receiving a message from a set top box over a communications link;

processing the message to determine whether or not the message is legitimate;

taking an action that depends on whether or not the message is legitimate.

23. The method defined in claim 22, wherein said processing the message comprises carrying out an attempt to decrypt the message using a key, wherein the message is determined to be legitimate if the attempt is successful and not legitimate otherwise.

24. The method defined in claim 23, further comprising accessing a memory to obtain the key.

25. The method defined in claim 24, further comprising sending the key to the STB over the communication link prior to receiving the message.

26. The method defined in claim 25, wherein said sending is in response to receipt of a key request message from the STB over the communication link.

27. The method defined in claim 26, further comprising sending a trigger to the STB to cause issuance of the key request message by the STB.

28. The method defined in claim 26, wherein the key comprises an identifier of the CSS.

29. The method defined in claim 24, the key being a decryption key, the method further comprising sending an encryption key different from the decryption key to the STB over the communication link prior to receiving the message.

30. The method defined in claim 29, wherein said sending is in response to receipt of a key request message from the STB over the communication link.

31. The method defined in claim 30, further comprising sending a trigger to the STB to cause issuance of the key request message by the STB.

32. The method defined in claim 30, wherein the encryption key is a public key of the CSS and wherein the decryption key is a private key of the CSS.

33. The method defined in claim 30, wherein said sending comprises encrypting the encryption key with a second encryption key.

34. The method defined in claim 33, further comprising accessing the memory to obtain the second encryption key.

35. The method defined in claim 34, further comprising storing the second encryption key in the memory further to receipt of the second encryption key from the STB over the communication link.

36. The method defined in claim 35, wherein the second encryption key is a STB public key.

37. The method defined in claim 35, wherein the second encryption key comprises part of the key request message.

38. The method defined in claim 22, wherein said processing the message comprises determining an identifier indicative of an originator of the message and validating the originator of the message, wherein the message is determined to be legitimate if the originator of the message is successfully validated and not legitimate otherwise.

39. The method defined in claim 38, wherein validating the originator of the message comprises consulting a memory that stores a list of authorized set top box identifiers, wherein the originator of the message is successfully validated if the identifier is on said list.

40. The method defined in claim 39, further comprising receiving the list from a head end via a satellite feed unit.

41. The method defined in claim 38, wherein validating the originator of the message comprises accessing a memory storing a list of unauthorized set top box identifiers, wherein the originator of the message is successfully validated if the identifier is not on said list.

42. The method defined in claim 41, further comprising receiving the list from a head end via a satellite feed unit.

43. The method defined in claim 22, wherein if the message is legitimate and contains a tuning request from the STB, said action comprises serving the tuning request on behalf of the STB.

44. The method defined in claim 43, wherein communication over the communication link takes place over a user band assigned to the STB.

45. The method defined in claim 44, wherein the tuning request specifies a desired satellite transponder channel, and wherein serving the tuning request comprises controlling a satellite feed unit to isolate from an ambient signal a wideband satellite signal, isolating the desired satellite transponder channel from the wideband satellite signal and frequency translating the desired satellite transponder channel into the user band assigned to the STB.

46. The method defined in claim 45, wherein controlling the satellite feed unit comprises setting a polarization of the wideband satellite signal.

47. The method defined in claim 45, wherein controlling the satellite feed unit comprises setting a frequency range of the wideband satellite signal.

48. The method defined in claim 22, wherein if the message is not legitimate, said action comprises returning an error message to the STB.

49. A channel stacking switch, comprising:

a communication interface configured to receive a message from a set top box;

a processing entity configured to determine whether or not the message is legitimate and to take an action that depends on whether or not the message is legitimate.

50. A computer-readable storage medium storing instructions for execution by a channel stacking switch (CSS), wherein execution of the instructions by the CSS causes the CSS to:

be attentive to receipt of a message from a set top box over a communications link;

process the message to determine whether or not the message is legitimate;

take an action that depends on whether or not the message is legitimate.

51. A satellite signal receiving system comprising a channel stacking switch and at least one set top box in secure communication with the channel stacking switch.