Simulcrypt key sharing with hashed keys

• US 8,204,220 B2
• Filed: 09/18/2008
• Issued: 06/19/2012
• 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.
• Primary Examiner(s): Nguyen, Thuong (Tina)
• Assistant Examiner(s): Eskandarnia, Arvin
• Application Number:
  US12/284,049
• Publication Number:
  US 20100067703A1
• Time in Patent Office: 1,370 Days
• Field of Search: 380/44
• US Class Current: 380/44
• 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 deriving a content key that is shared among a plurality of conditional access (CA) vendors having independent CA systems with each CA system using independent key generation methods, the shared content key used at an encrypter as a control word to encrypt content, the method comprising:

receiving a CA Value contribution from each of the plurality of CA vendors at the encrypter, where each CA Value contribution comprises a code word that is independently generated by each of the CA vendors;

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

at the encrypter using the output control word as a shared content key, wherein the shared 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 independent conditional access systems;

wherein there are at least two CA Value contributions CAV1 and CAV2 and wherein CAV1 is used as an encryption key to encrypt CAV2 to produce an encrypted output; and

wherein one of CAV1 and CAV2 is combined with the encrypted output in an Exclusive OR process.

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

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

5. The method according to claim 1, wherein the encryption comprises one of DES, DVB common scrambling and AES encryption.

6. The method according to claim 1, further comprising sending the CA Value contributions to a plurality of receivers.

7. The method according to claim 6, further comprising sending the CA Value contributions to the plurality of receivers in an Entitlement Control Message (ECM).

8. The method according to claim 6, further comprising sending the hashing algorithm to the plurality of receivers.

9. A non-transitory computer readable electronic storage instructions which when executed on one or more programmed processors, carry out a process according to claim 1.

10. A SimulCrypt apparatus that shares keys among a plurality of conditional access (CA) vendors having independent CA systems using independent key generation methods, comprising:

A synchronizer adapted to receive a CA Value contribution from each of the plurality of CA vendors, where each CA Value contribution comprises a code word that is independently generated by each of the CA vendors;

A hashing processor configured to hash the CA Values contributions from each of the plurality of CA vendors together using a hashing function to produce an output control word for encryption of the content;

an encrypter configured to use the output control word as a shared content key to encrypt content provided to a plurality of receivers that decrypt the content using any of the independent conditional access systems;

wherein there are at least two CA Value contributions CAV1 and CAV2 and wherein CAV1 is used as an encryption key to encrypt CAV2 to produce an encrypted output; and

wherein one of CAV1 and CAV2 is combined with the encrypted output in an Exclusive OR process.

11. The apparatus according to claim 10, further comprising means for sharing the CA Value contributions among the plurality of CA vendors.

12. The apparatus according to claim 11, wherein the sharing is carried out by directly providing the CA Value contributions of each CA vendor to each other CA vendor.

13. The apparatus according to claim 11, wherein the sharing is carried out by indirectly providing the CA Value contributions of each CA vendor to each other vendor, wherein the CA Value contributions provided to each vendor comprises a hash of the other vendor'"'"'s CA Value contributions.

14. The apparatus according to claim 10, wherein the encryption comprises one of DES, DVB common scrambling and AES encryption.

15. The apparatus according to claim 10, further comprising an ECM generator that generates Entitlement Control Messages (ECMs) that carry the CA Value contributions to the plurality of receivers.

16. The apparatus according to claim 15, wherein the ECM generator further generates ECMs that send the hashing algorithm to the plurality of receivers.

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

receiving a plurality of Conditional Access (CA) Value contributions, where each CA Value contribution comprises a code word that is independently generated by each of the CA vendors;

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, the content being encrypted using the CW;

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

wherein there are at least two CA Value contributions CAV1 and CAV2 and wherein CAV1 is used as an encryption key to encrypt CAV2 to produce an encrypted output; and

wherein one of CAV1 and CAV2 is combined with the encrypted output in an Exclusive OR process.

18. The method according to claim 17, wherein the encryption comprises one of DES, DVB common scrambling and AES encryption.

19. The method according to claim 17, wherein the CA Value contributions are received by the receiver in an Entitlement Control Message (ECM).

20. The method according to claim 17, further comprising receiving the hashing algorithm at the receiver.

21. A non-transitory computer readable electronic storage instructions which when executed on one or more programmed processors, carry out a process according to claim 17.