Key delivery in a secure broadcasting system

• US 6,587,561 B1
• Filed: 02/04/1999
• Issued: 07/01/2003
• Est. Priority Date: 03/04/1998
• Status: Expired due to Term

• Current Assignee: Synamedia Limited
• Original Assignee: NDS Limited (Cisco Systems, Inc.)
• Inventors: Dallard, Nigel Stephen, Sered, Yishai
• Primary Examiner(s): Darrow, Justin T.
• Application Number:
  US09/244,597
• Time in Patent Office: 1,608 Days
• Field of Search: 380/201, 380/204, 380/227, 380/228, 380/224, 380/230, 380/231, 380/240, 380/242, 380/279, 380/283, 713/160, 713/162, 713/163, 713/201, 705/51, 705/52, 705/57
• US Class Current: 380/241
• 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 21/4623 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 21/6334 for authorisation, e.g. by transmitting a key wireless communications network key management H04W12/04; wireless communications network access security H04W12/08
• 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 key delivery method for use in an encoded communications system in which at least one encoded item including a first item encoded with a first item control word is sent in a communication stream from a sender to a receiver, the method including transmitting an item entitlement control message (IECM) including item control information, transmitting a stream entitlement control message (SECM) including stream control information, and combining at least part of the item control information and at least part of the stream control information to produce the first item control word. Related methods and apparatus are also disclosed.

Claims

1. A key delivery method for use in an encoded communications system in which a first plurality of encoded items comprising at least a first item encoded with a first item control word and a second item encoded with a second item control word is sent in a communication stream from a sender to a receiver, the method comprising:

transmitting a first item entitlement control message (IECM) comprising first item control information for controlling only the first item and a second IECM comprising second item control information for controlling only the second item;

transmitting a stream entitlement control message (SECM) comprising stream control information for controlling more than one item;

combining at least part of the first item control information and at least part of the stream control information to produce the first item control word; and

combining at least part of the second item control information and at least part of the stream control information to produce the second item control word,

wherein said transmitting-IECM step is performed before said transmitting-SECM step.

2. A method according to claim 1 and also comprising:

performing at least one of the following;

utilizing the first item control word to decode the first encoded item; and

utilizing the second item control word to decode the second encoded item.

3. A method according to claim 1 and wherein:

the first item control information comprises a first item key, and

the second item control information comprises a second item key, and

the stream control information comprises a stream key, and

the combining step comprises;

computing the first item control word from the first item key and the stream key; and

computing the second item control word from the second item key and the stream key.

4. A method according to claim 1 and wherein:

the first item control information comprises a first item seed, and

the second item control information comprises a second item seed,

the stream control information comprises a stream seed, and

the combining step comprises;

computing a first item key from the first item seed using an item key production function;

computing a second item key from the second item seed using the item key production function;

computing a stream key from the stream seed using a stream key production function;

computing the first item control word from the first item key and the stream key; and

computing the second item control word from the second item key and the stream key.

5. A method according to claim 4 and wherein the step of computing an first item key comprises:

determining whether the receiver is authorized to compute the first item key and computing the first item key only if the receiver is authorized to compute the item key, and

the step of computing a second item key comprises;

determining whether the receiver is authorized to compute the second item key and computing the second item key only if the receiver is authorized to compute the second item key.

6. A method according to claim 4 and wherein the step of computing a stream key comprises:

determining whether the receiver is authorized to compute the stream key and computing the stream key only if the receiver is authorized to compute the stream key.

7. A method according to claim 1 and wherein the at least one encoded item is transmitted asynchronously to the SECM.

8. A method according to claim 1 and wherein each of said first plurality of encoded items has a time duration, and

said SECM comprises a second plurality of SECMs transmitted with an average inter-SECM delay, and

each of said first plurality of encoded items is associated with one of the second plurality of SECMs, and

the time duration of at least one of said first plurality of encoded items is less than the average inter-SECM delay.

9. A method according to claim 8 and wherein more than one of said first plurality of encoded items is associated with at least one of said second plurality of SECMs.

10. A method according to claim 1 and wherein the first encoded item and the second encoded item are transmitted simultaneously.

11. A method according to claim 1 and wherein at least one of the first item control information and the second item control information comprises item purchase information.

12. A method according to claim 11 and wherein the item purchase information includes item price information.

13. A method according to claim 11 and wherein the item purchase information comprises purchase access information and the method includes:

determining whether the receiver is entitled to purchase at least one of the first item and the second item based, at least in part, on the purchase access information.

14. A method according to claim 11 and wherein the item purchase information comprises access information and the method includes:

determining whether the receiver is entitled to access at least one of the first item and the second item based, at least in part, on the access information.

15. A method according to claim 1 and wherein the stream control information comprises item purchase information.

16. A method according to claim 1 and wherein the first item is broadcast to a plurality of item receivers including the receiver.

17. A method according to claim 16 and wherein the transmitting-IECM step includes broadcasting at least one of the first IECM and the second IECM.

18. A method according to claim 16 and wherein the step of transmitting an SECM includes broadcasting the SECM.

19. A method according to claim 1 and wherein each of the plurality of encoded items has a time duration, and

the time duration of the first item and the time duration of the second item at least partially overlap.