Simulcrypt key sharing with hashed keys

• US 20100067703A1
• Filed: 09/18/2008
• Published: 03/18/2010
• Est. Priority Date: 09/18/2008
• Status: Active Grant

• 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.
• Granted Patent: US 8,204,220 B2
• Time in Patent Office: Days
• US Class Current: 380/283
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 2209/601 Broadcast encryption
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/062 for key distribution, e.g. centrally by trusted party cryptographic mechanisms or cryptographic arrangements for key distribution involving a central third party H04L9/0819
• CPC Class Codes: H04L 9/065 Encryption by serially and continuously modifying data stream elements, e.g. stream cipher systems, RC4, SEAL or A5/3
• CPC Class Codes: H04L 9/0838 Key agreement, i.e. key establishment technique in which a shared key is derived by parties as a function of information contributed by, or associated with, each of these network architectures or network communication protocols for key exchange in a packet data network H04L63/061
• CPC Class Codes: H04N 21/2221 being a cable television head-end CATV in broadcast systems H04H20/78
• CPC Class Codes: H04N 21/2541 Rights Management protecting software against unauthorised usage in a vending or licensing environment G06F21/10; security in data switching network management H04L41/28; security management or policies for network security H04L63/20; access security in wireless networks H04W12/08
• 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 21/26613 for generating or managing keys in general key distribution for secret or secure communication involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP] H04L9/083; network support of key management H04L63/06; key management for network security in communication control or processing H04W12/04

Abstract

A method of sharing keys among a plurality of conditional access (CA) vendors having differing CA systems used at a distribution headend involves receiving a CA Value contribution from each of the plurality of CA vendors at the headend; hashing the CA Values from each of the plurality of CA vendors together using a hashing function to produce an output control word; and at an encrypter at the headend, using the output control word as a content key, wherein the content key is used as an encryption key to encrypt content provided to a plurality of receivers that decrypt the content using any of the conditional access systems. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.

Claims

1. A method of sharing keys among a plurality of conditional access (CA) vendors having differing CA systems used at a distribution headend, the method comprising:

receiving a CA Value contribution from each of the plurality of CA vendors at the headend;

hashing the CA Values from each of the plurality of CA vendors together using a hashing function to produce an output control word; and

at an encrypter at the headend, using the output control word as a content key, wherein the content key is used as an encryption key to encrypt content provided to a plurality of receivers that decrypt the content using any of the conditional access systems.

2. The method according to claim 1, further comprising sharing the CA Values among the plurality of CA vendors.

3. The method according to claim 2, wherein the sharing is carried out by directly providing the CA Values of each CA vendor to each other CA vendor.

4. The method according to claim 2, wherein the sharing is carried out by indirectly providing the CA Values of each CA vendor to each other vendor, wherein the CA Values provided to each vendor comprises a hash of the other vendor'"'"'s CA Values.

5. The method according to claim 1, wherein there are at least two CA Values CAV1 and CAV2 and wherein CAV1 is used as an encryption key to encrypt CAV2 to produce an encrypted output.

6. The method according to claim 5, wherein one of CAV1 and CAV2 is combined with the encrypted output in an Exclusive OR process.

7. The method according to claim 5, wherein the encryption comprises one of DES, DVB common scrambling and AES encryption.

8. The method according to claim 1, further comprising sending the CA Values to a plurality of receivers.

9. The method according to claim 8, further comprising sending the CA Values to the plurality of receivers in an Entitlement Control Message (ECM).

10. The method according to claim 8, further comprising sending the hashing algorithm to the plurality of receivers.

11. A tangible computer readable electronic storage medium storing instructions which, when executed on one or more programmed processors, carry out a process according to claim 1.

12. A SimulCrypt headend apparatus that shares keys among a plurality of conditional access (CA) vendors having differing CA systems, comprising:

means for receiving a CA Value contribution from each of the plurality of CA vendors at the headend;

a hashing processor that hashes the CA Values from each of the plurality of CA vendors together using a hashing function to produce an output control word; and

an encrypter that uses the output control word as a content key as encryption key to encrypt content provided to a plurality of receivers that decrypt the content using any of the conditional access systems.

13. The apparatus according to claim 12, further comprising means for sharing the CA Values among the plurality of CA vendors.

14. The apparatus according to claim 13, wherein the sharing is carried out by directly providing the CA Values of each CA vendor to each other CA vendor.

15. The apparatus according to claim 13, wherein the sharing is carried out by indirectly providing the CA Values of each CA vendor to each other vendor, wherein the CA Values provided to each vendor comprises a hash of the other vendor'"'"'s CA Values.

16. The apparatus according to claim 12, wherein there are at least two CA Values CAV1 and CAV2 and wherein CAV1 is used as an encryption key to encrypt CAV2 to produce an encrypted output.

17. The apparatus according to claim 16, wherein one of CAV1 and CAV2 is combined with the encrypted output in an Exclusive OR process.

18. The apparatus according to claim 16, wherein the encryption comprises one of DES, DVB common scrambling and AES encryption.

19. The apparatus according to claim 12, further comprising an ECM generator that generates Entitlement Control Messages (ECMs) that carry the CA Values to the plurality of receivers.

20. The apparatus according to claim 19, wherein the ECM generator further generates ECMs that send the hashing algorithm to the plurality of receivers.

21. A method of receiving encrypted content with shared keys at a receiver, the shared keys being keys shared among a plurality of Conditional Access (CA) vendors having different CA systems, the method comprising:

receiving a plurality of Conditional Access (CA) Value contributions;

hashing the CA Value contributions to re-derive a control word (CW) used as a content encryption key for use in the receiver;

receiving content at the receiver encrypted using the CW; and

decrypting the content at the receiver using the re-derived CW.

22. The method according to claim 21, wherein there are at least two CA Values CAV1 and CAV2 and wherein CAV1 is used as an encryption key to encrypt CAV2 to produce an encrypted output.

23. The method according to claim 22, wherein one of CAV1 and CAV2 is combined with the encrypted output in an Exclusive OR process.

24. The method according to claim 22, wherein the encryption comprises one of DES, DVB common scrambling and AES encryption.

25. The method according to claim 21, wherein the CA Values are received by the receiver in an Entitlement Control Message (ECM).

26. The method according to claim 21, further comprising receiving the hashing algorithm at the receiver.

27. A tangible computer readable electronic storage medium storing instructions which, when executed on one or more programmed processors, carry out a process according to claim 21.