Method and system for preventing revocation denial of service attacks

• US 9,461,825 B2
• Filed: 05/02/2007
• Issued: 10/04/2016
• Est. Priority Date: 01/30/2004
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Rodgers, Stephane, Dellow, Andrew
• Primary Examiner(s): HERZOG, MADHURI R
• Application Number:
  US11/743,533
• Publication Number:
  US 20080086641A1
• Time in Patent Office: 3,443 Days
• Field of Search: 380200-203, 380239-242, 380/255, 380/259, 380277- 30, 380277-286, 713/168, 713176-180, 726 26- 33, 705 50- 59
• US Class Current: 1/1
• CPC Class Codes: G06F 21/1014 to tokens
• CPC Class Codes: G06F 21/1076 Revocation
• CPC Class Codes: H04L 2209/60 Digital content management, e.g. content distribution
• CPC Class Codes: H04L 2209/605 Copy protection
• CPC Class Codes: H04L 2463/062 applying encryption of the keys cryptographic mechanisms or cryptographic arrangements for key distribution using key encryption key H04L9/0822
• CPC Class Codes: H04L 63/0435 wherein the sending and receiving network entities apply symmetric encryption, i.e. same key used for encryption and decryption cryptographic mechanisms or cryptographic arrangements for symmetric key encryption H04L9/06
• CPC Class Codes: H04L 63/123 received data contents, e.g. message integrity
• CPC Class Codes: H04L 63/1458 Denial of Service
• CPC Class Codes: H04L 9/0891 Revocation or update of secret information, e.g. encryption key update or rekeying
• CPC Class Codes: H04L 9/3247 involving digital signatures

Abstract

Methods and systems for preventing revocation denial of service attacks are disclosed and may include receiving and decrypting a command for revoking a secure key utilizing a hidden key, and revoking the secure key upon successful verification of a signature. The command may comprise a key ID that is unique to a specific set-top box. A key corresponding to the command for revoking the secure key may be stored in a one-time programmable memory, compared to a reference, and the security key may be revoked based on the comparison. The command for revoking the secure key may be parsed from a transport stream utilizing a hardware parser. The method and system may also comprise generating a command for revoking a secure key. The command may be encrypted and signed utilizing a hidden key and may comprise a key ID that is unique to a specific set-top box.

Claims

1. A method for signal processing, the method comprising:

in a secure communication system in an integrated circuit;

receiving an encrypted transport stream;

decrypting said encrypted transport stream;

extracting from said decrypted transport stream, a command for revoking a secure key, wherein said secure key is encrypted;

decrypting said command for revoking said secure key utilizing a hidden key;

verifying a signature of said decrypted command for revoking said secure key; and

revoking said secure key upon successful verification of said signature.

2. The method according to claim 1, wherein said secure key is signed.

3. The method according to claim 1, wherein said command for revoking said secure key comprises a key ID that is unique to a specific set-top box.

4. The method according to claim 1, wherein said secure key is encrypted using an encryption key that is unique to a specific set-top box.

5. The method according to claim 1, further comprising storing a revocation key corresponding to said command for revoking said secure key in a one-time programmable memory.

6. The method according to claim 5, further comprising comparing said stored revocation key with a reference.

7. The method according to claim 6, further comprising revoking said secure key based on said comparison.

8. The method according to claim 6, wherein said reference is stored in said one-time programmable memory.

9. The method according to claim 1, further comprising parsing said command for revoking said secure key from said decrypted transport stream.

10. The method according to claim 1, further comprising parsing via hardware said command for revoking said secure key from said decrypted transport stream.

11. A method for signal processing, the method comprising:

generating a command for revoking a secure key, wherein said secure key is encrypted;

encrypting said command for revoking said secure key utilizing a hidden key;

signing said encrypted command for revoking said secure key;

combining said signed and encrypted command with video data being transmitted to a secure communication system; and

encrypting said combined video data and said signed and encrypted command.

12. The method according to claim 11, wherein said command for revoking said secure key comprises a key ID that is unique to a specific set-top box.

13. The method according to claim 11, wherein said secure key is encrypted using an encryption key that is unique to a specific set-top box.

28. The method according to claim 11, wherein said secure communication system comprises a set-top box.

14. A system for signal processing, the system comprising:

one or more circuits for receiving an encrypted transport stream, said one or more circuits configured to;

decrypt said encrypted transport stream;

extract from said decrypted transport stream, a command that revokes a secure key, wherein said secure key is encrypted;

decrypt said command for revoking said secure key utilizing a hidden key;

verify a signature of said decrypted command for revoking said secure key; and

revoke said secure key upon successful verification of said signature.

15. The system according to claim 14, wherein said secure key is signed.

16. The system according to claim 14, wherein said command for revoking said secure key comprises a key ID that is unique to a specific set-top box.

17. The system according to claim 14, wherein said secure key is encrypted using an encryption key that is unique to a specific set-top box.

18. The system according to claim 14, wherein said one or more circuits are further configured to store a revocation key corresponding to said command for revoking said secure key in a one-time programmable memory.

19. The system according to claim 18, wherein said one or more circuits are further configured to compare said stored revocation key with a reference.

20. The system according to claim 19, wherein said one or more circuits are further configured to revoke said secure key based on said comparison.

21. The system according to claim 19, wherein said reference is stored in said one-time programmable memory.

22. The system according to claim 14, wherein said one or more circuits are further configured to parse said command for revoking said secure key from said decrypted transport stream.

23. The system according to claim 14, wherein said one or more circuits parses via hardware, said command for revoking said secure key from said decrypted transport stream.

24. A system for signal processing, the system comprising:

one or more circuits configured to;

generate a command for revoking a secure key, wherein said secure key is encrypted;

encrypt said command for revoking said secure key utilizing a hidden key;

sign said encrypted command for revoking said secure key;

combine said signed and encrypted command with video data being transmitted to a secure communication system; and

encrypt said combined video data and said signed and encrypted command.

25. The system according to claim 24, wherein said command for revoking said secure key comprises a key ID that is unique to a specific set-top box.

26. The system according to claim 24, wherein said secure key is encrypted using an encryption key that is unique to a specific set-top box.

27. The system according to claim 24, wherein said secure communication system comprises a set-top box.