Method and apparatus for securing control words

• US 7,302,058 B2
• Filed: 01/22/2004
• Issued: 11/27/2007
• 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): Song, Hosuk
• Application Number:
  US10/763,865
• Publication Number:
  US 20040151314A1
• Time in Patent Office: 1,405 Days
• Field of Search: 380/200, 380/239, 380/241, 380277-278, 713/189, 713/192, 725114-116
• 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 comprising:

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

sending a request for the encrypted control data to a headend, the request being sent over an out-of-band channel;

receiving control data in an encrypted format by descrambler integrated circuit;

decrypting the encrypted control data entirely within the descrambler integrated circuit using a 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 digital program data if the digital program data belongs to selected group of programs each of which is capable of being descrambler 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 digital program data comprises audio and visual data.

5. The method of claim 4, 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.

6. 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.

7. 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.

8. A method comprising:

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

sending a request for the encrypted control data to a headend, the request being transmitted in accordance with a Data Over Cable Service Interface Specfication (DOCSIS) cable transmission protocol;

receiving control data in an encrypted format by the descrambler integrated circuit;

decrypting the encrypted control data entirely within the descrambler integrated circuit using a 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.

9. The method of claim 8, 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.

10. A method comprising:

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

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;

receiving control data in an encrypted format by the descrambler integrated circuit;

decrypting the encrypted control data entirely within the descrambler integrated circuit;

using a 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.

11. The method of claim 10, wherein prior to receiving the encrypted control data, the method further comprising receiving the encrypted control data by an interface removably coupled to the smart card, the interface being part of a digital receiver implemented with the descrambler integrated circuit.

12. The method of claim 11, wherein the interface includes an expansion slot built into the digital receiver.

13. A descrambler integrated circuit adapted for implementation in a conditional access unit, comprising:

a memory to permanently store a key uniquely assigned to the descrambler integrated circuit, the memory being a one-time programmable non-volatile memory;

decryption logic coupled to the memory, the decrypt logic to decrypt the encrypted data using the key completely within the descrambler integrated circuit without accessing any information external to the decryption logic, the encrypted data being a service key in an encrypted format being valid for a prescribed period of time, the encrypted service key, when decrypted, to descramble a 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; and

a descrambler coupled to the decryption logic, the descrambler to descramble the scrambled, digital program data within the descrambler integrated circuit using data recovered by decrypting the encrypted data

wherein the descrambler integrated circuit being controlled by a processor in communications with a transmitter implemented within the conditional access unit, the transmitter to transmit a request for the service key in the encrypted format to a headend.

14. The descrambler integrated circuit of claim 13, wherein the memory is a one-time programmable register.

15. The descrambler integrated circuit of claim 13, wherein the request for the service key is transmitted over an out-of-band channel.

16. A descrambler integrated circuit adapted for implementation in a conditional access unit, comprising:

a memory to permanently store a key uniquely assigned to the descrambler integrated circuit, the memory being a one-time programmable non-volatile memory, the key is stored within the memory during manufacturer, at which time, the key and a serial number associated with conditional access unit implemented with the descrambler integrated circuit are recorded by storage external from the descrambler integrated circuit;

decryption logic coupled to the memory, the decrypt logic to decrypt the encrypted data using the key completely within the descrambler integrated circuit without accessing any information external to the decryption logic; and

a descrambler coupled to the decryption logic, the descrambler to descramble incoming scrambled digital program data within the descrambler integrated circuit using data recovered by decrypting the encrypted data.

17. A apparatus comprising:

a first interface to receive encrypted data, 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 incoming 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; and

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

a memory to permanently store a key uniquely assigned to the descrambler integrated circuit, the memory being a one-time programmable non-volatile memory,

decryption logic to decrypt the encrypted data using the key completely within the descrambler integrated circuit without accessing any information external to the decryption logic, and

a descrambler to descramble the incoming scrambled, digital content within the descrambler integrated circuit using data recovered by decrypting the encrypted data.

18. The apparatus of claim 17, wherein the first interface includes an expansion slot to receive a smart card.

19. The apparatus of claim 17, wherein the memory of the descrambler integrated circuit is a register that can be only programmed once.

20. The apparatus of claim 17, wherein the encrypted data is an encrypted control word.

21. The apparatus of claim 17, further comprising a transmitter to transmit a request for the service key in the encrypted format over an out-of-band channel directed to a headend.

22. The apparatus of claim 17, wherein the memory of the descrambler integrated circuit is configured to prevent the permanent key from being overwritten of from being read by a source external to the descrambler integrated circuit.

23. The apparatus of claim 17, wherein the key and a serial number of the apparatus are recorded and stored externally from the descrambler integrated circuit.

24. The apparatus of claim 17, wherein the descrambler integrated circuit is devoid of a central processing unit, software or firmware.

25. The apparatus of claim 17 is a conditional access unit.

26. An apparatus comprising:

a first interface to receive encrypted data;

a processor coupled to the first interface

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 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; 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 to the descrambler integrated circuit, the memory being a one-time programmable non-volatile memory,

decryption logic to decrypt the encrypted data using the key completely within the descrambler integrated circuit without accessing any information external to the decryption logic, and

a descrambler to descramble the scrambled digital content within the descrambler integrated circuit using data recovered by decrypting the encrypted data.