Method and apparatus for securing control words

• US 6,697,489 B1
• Filed: 02/03/2000
• Issued: 02/24/2004
• Est. Priority Date: 03/30/1999
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.), Sony Electronics Inc. (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.), Sony Electronics Inc. (Sony Group Corp.)
• Inventors: Candelore, Brant L.
• Primary Examiner(s): Sheikh, Ayaz
• Assistant Examiner(s): Song, Hosuk
• Application Number:
  US09/497,393
• Time in Patent Office: 1,482 Days
• Field of Search: 380/200-203, 380/210, 380/239-241, 380/227-228, 380/223, 380/277-278, 713/189, 713/192-194, 386/94, 386/108, 725/116, 725/114, 725/115
• US Class Current: 380/200
• CPC Class Codes: H04N 21/2347 involving video stream encryption
• CPC Class Codes: H04N 21/2543 Billing , e.g. for subscription services payment schemes, architectures or protocols G06Q20/00; e-commerce G06Q30/00; arrangements for billing for the use of broadcast information or broadcast-related information H04H60/21
• 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 21/47211 for requesting pay-per-view content payment schemes payment architectures or payment protocols G06Q20/00, G07F
• 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 7/163 by receiver means only
• CPC Class Codes: H04N 7/167 Systems rendering the television signal unintelligible and subsequently intelligible
• 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

In accordance with one embodiment, a method for securing control words is provided. The method includes receiving scrambled digital content in a descrambler integrated circuit. The method further includes receiving an encrypted control word in the descrambler integrated circuit, decrypting the encrypted control word using a key stored in a register circuit of the descrambler integrated circuit, and descrambling the scrambled digital content in the descrambler integrated circuit using the decrypted control word.

Claims

1. A method of descrambling digital multimedia content, comprising:

sending an out-of-band request for encrypted control data to a headend;

receiving digital program data in a scrambled format by a descrambler integrated circuit;

receiving the encrypted control data by the descrambler integrated circuit;

decrypting the encrypted control data entirely within the descrambler integrated circuit using a unique key permanently stored in the descrambler integrated circuit; and

descrambling the scrambled digital program data in the descrambler integrated circuit using the decrypted control data.

2. The method of claim 1, wherein the control data includes a service key to descramble the scrambled digital program data if the digital program data belongs to a selected group of programs each of which is capable of being descrambled by the service key.

3. The method of claim 1, wherein prior to receiving the scrambled digital program data, the method further comprising programming the permanent key into a memory at manufacture of a digital device including the descrambler integrated circuit, the key being non-modifiable.

4. The method of claim 1, wherein the out-of-band request includes (i) an address of a digital device implemented with the descrambler integrated circuit and (ii) an identifier of a channel at which the digital program data is received.

5. The method of claim 1, wherein prior to receiving of the encrypted control data, the method further comprising:

within a smart card including a processor and a programmable memory to contain a copy of the key, encrypting the control data being a control word by the processor to produce an encrypted control word; and

providing the encrypted control word to the descrambler integrated circuit.

6. The method of claim 1, wherein prior to receiving the encrypted control data, the method further comprising encrypting the control data in a smart card using a key stored in a register circuit of the smart card, the key stored in the register circuit of the smart card being equivalent to the key permanently stored in the descrambler integrated circuit.

7. The method of claim 6, wherein prior to receiving the encrypted control data, the method further comprising receiving the encrypted control data by an interface adapted for removable connection to the smart card being part of a digital receiver implemented with the descrambler integrated circuit.

8. The method of claim 7, wherein the interface includes an expansion slot built into the digital receiver.

9. The method of claim 1, wherein the digital program data comprises audio and visual data.

10. The method of claim 9, wherein the digital program data further comprises system information including one or more of a program name, broadcast time, and source of the digital program data.

11. The method of claim 1, wherein the digital program data comprises an entitlement management message to deliver privileges to a digital receiver implemented with the descrambler integrated circuit.

12. The method of claim 1, wherein the digital program data comprises an entitlement control message including at least one of an identifier of a channel being tuned for receipt of the scrambled digital program data, an identifier to locate the key stored in the descrambler integrated circuit, and an identifier of the digital program data being broadcast.

13. The apparatus of claim 1, wherein the sending of the out-of-band request is conducted over a communication path in accordance with Data Over Cable Service Interface Specification (DOCSIS).

14. An apparatus comprising:

means for receiving digital program data in a scrambled format and an control datum in an encrypted format by a descrambler integrated circuit;

means for decrypting the encrypted control datum entirely within the descrambler integrated circuit using a unique key permanently stored in the descrambler integrated circuit, the control datum and the key precluded from being exposed in an unencrypted format outside the descrambler integrated circuit; and

means for descrambling the scrambled digital program data in the descrambler integrated circuit using the control datum, the digital program data comprises an entitlement control message including at least one of an identifier of a channel being tuned for receipt of the scrambled digital program data, an identifier to locate the key stored in the descrambler integrated circuit, and an identifier of the digital program data.

15. The apparatus of claim 14 further comprising:

means for storing the key being programmed at manufacture.

16. The apparatus of claim 14, wherein the digital program data includes audio and visual data.

17. The apparatus of claim 14, wherein the digital program data includes an entitlement management message to deliver privileges to a digital receiver implemented with the descrambler integrated circuit.

18. A method of descrambling digital multimedia content, comprising:

requesting control data from a headend, the control data being a service key to descramble digital program data on a channel tuned to by a digital device implemented with the descrambler integrated circuit;

receiving the digital program data in a scrambled format by a descrambler integrated circuit;

decrypting the control data stored in an encrypted format entirely within the descrambler integrated circuit using a unique key permanently stored in the descrambler integrated circuit; and

descrambling the scrambled digital program data in the descrambler integrated circuit using the decrypted control data.

19. The method of claim 18, wherein the control data includes a service key to descramble the scrambled digital program data only if the digital program data belongs to a selected group of programs each of which capable of being descrambled by the service key.

20. The method of claim 18, wherein prior to receiving the scrambled digital program data, the method further comprising:

storing the encrypted control data within memory of a digital device implemented with the descrambler integrated circuit.

21. An apparatus comprising:

a transmitter to transmit a request for an encrypted service key over an out-of-band channel directed to a head-end;

a first interface to receive encrypted data; and

a descrambler integrated circuit in communication with the first interface, the descrambler integrated circuit comprises

a memory to permanently store a key uniquely assigned for the descrambler integrated circuit, the key incapable of being overwritten,

decryption logic to decrypt the encrypted data using the key completely within the descrambler integrated circuit, and

a descrambler to descramble incoming scrambled, digital program data completely within the descrambler integrated circuit using the decrypted data.

22. The apparatus of claim 21, wherein the first interface includes an expansion slot to receive a smart card.

23. The apparatus of claim 21, wherein the memory of the descrambler integrated circuit is a register that can be only programmed once.

24. The apparatus of claim 21 further comprising a processor coupled to the first interface.

25. The apparatus of claim 24, further comprising an internal memory device coupled to the processor, the internal memory to store an encrypted service key being the encrypted data, the service key, when decrypted, to descramble the scrambled, digital program data if the digital program data belongs to a selected group of programs each of which capable of being descrambled by the service key.

26. The apparatus of claim 21, wherein the encrypted data is an encrypted control word.

27. The apparatus of claim 21, wherein the encrypted data is a service key in an encrypted format being valid for a prescribed period of time, the service key, when decrypted, to descramble the scrambled, digital program data if the digital program data belongs to a selected group of programs each of which capable of being descrambled by the service key.

28. The apparatus of claim 21, wherein the out-of-band channel is provided by a Data Over Cable Service Interface Specification (DOCSIS) modem.

29. The apparatus of claim 21, wherein the request includes (i) an address of a digital device implemented with the descrambler integrated circuit and (ii) an identifier of a channel at which the disital program data is received.