Content security system for screening applications

• US 7,536,355 B2
• Filed: 12/22/2004
• Issued: 05/19/2009
• Est. Priority Date: 06/10/2004
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: LSI Corporation (Broadcom, Inc.)
• Inventors: Barr, David A., Wells, Aaron G.
• Primary Examiner(s): Hewitt, II; Calvin L
• Assistant Examiner(s): Ravetti; Dante
• Application Number:
  US11/021,101
• Publication Number:
  US 20050278257A1
• Time in Patent Office: 1,609 Days
• Field of Search: 705/57
• US Class Current: 705/57
• CPC Class Codes: G06F 21/10 Protecting distributed programs or content, e.g. vending or licensing of copyrighted material protection in video systems or pay television H04N7/16 ; Digital rights management [DRM]
• CPC Class Codes: G06Q 20/3829 involving key management
• CPC Class Codes: G11B 20/00086 Circuits for prevention of unauthorised reproduction or copying, e.g. piracy indicating unauthorised use of record carriers in general G11B23/28; scrambling for television signal recording H04N5/913; network architectures or network protocols for network security H04L63/00; cryptographic mechanisms or cryptographic arrangements for secret or secure communication H04L9/00
• CPC Class Codes: G11B 20/0021 involving encryption or decryption of contents recorded on or reproduced from a record carrier
• CPC Class Codes: G11B 20/00362 the key being obtained from a media key block [MKB]
• CPC Class Codes: G11B 20/00528 wherein each title is encrypted with a separate encryption key for each title, e.g. title key for movie, song or data file
• CPC Class Codes: H04L 2209/606 Traitor tracing
• CPC Class Codes: H04L 9/0827 involving distinctive intermediate devices or communication paths network architectures or network communication protocols using different networks H04L63/18
• CPC Class Codes: H04L 9/0891 Revocation or update of secret information, e.g. encryption key update or rekeying
• CPC Class Codes: H04N 21/25816 involving client authentication restricting access to computer systems by authenticating users using a predetermined code G06F21/33; cryptographic authentication protocols H04L9/32; networks authentication protocols H04L63/08; authentication in wireless network security H04W12/06
• CPC Class Codes: H04N 21/4181 for conditional access
• CPC Class Codes: H04N 21/42646 for reading from or writing on a non-volatile solid state storage medium, e.g. DVD, CD-ROM
• CPC Class Codes: H04N 21/4623 Processing of entitlement messages, e.g. ECM [Entitlement Control Message] or EMM [Entitlement Management Message] arrangements for conditional access to broadcast information or to broadcast-related services H04H60/14
• CPC Class Codes: H04N 21/8355 involving usage data, e.g. number of copies or viewings allowed
• CPC Class Codes: H04N 21/8358 involving watermark protecting executable software by watermarking G06F21/16; image watermarking in general G06T1/0021; watermarks inserted in still images for transmission purposes H04N1/32144; inserting watermarks during video coding H04N19/467
• 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

A method for securing a content is disclosed. The method generally includes the steps of (A) generating a media key by decrypting a media key block based on a device key unique to a particular player of a plurality of players, (B) modifying the media key by decryption based on a class key such that the media key is unique for each of a plurality of subscriber classes, (C) writing an encrypted title key in a media by encrypting a title key based on both the media key after modification and a media identification value unique to the media and (D) writing an encrypted content in the media by encrypting the content based on the title key.

Claims

1. A method for securing a content, comprising the steps of:

(A) receiving said content at a recorder from a source;

(B) receiving a class key at said recorder from an owner of said content;

(C) reading a media key block and a media identification value of a medium with said recorder, said media key block containing a set of encrypted keys;

(D) generating a first media key with said recorder by decrypting at least one encrypted key from said set of encrypted keys in said media key block based on a device key, wherein said device key is unique to a particular player of a plurality of players;

(E) assigning a second media key to one of a plurality of subscriber classes with said recorder by applying a decryption cipher to said first media key using said class key;

(F) generating an encrypted title key with said recorder by encrypting a title key based on both said second media key and said media identification value;

(G) generating an encrypted content with said recorder by encrypting said content based on said title key; and

(H) writing said encrypted content and said encrypted title key in said medium with said recorder.

2. The method according to claim 1, further comprising the step of:

writing said class key in a smart card.

3. The method according to claim 2, further comprising the step of:

setting an enable value in said smart card, wherein said enable value enables regeneration of said second media key in each of said players.

4. The method according to claim 2, further comprising the step of:

writing said title key in said smart card.

5. The method according to claim 1, further comprising the step of:

writing data in one of (i) said medium and (ii) a smart card, wherein said data authenticates a password entered at said particular player.

6. The method according to claim 1, further comprising the step of:

writing a control value in said medium, wherein said control value controls media to control a plurality of permissions in said players to use said content.

7. The method according to claim 1, further comprising the step of:

writing a protection value in said medium, wherein (i) said protection value enables an analog protection system in said particular player and (ii) said analog protection system hampers copying of an analog signal representation of said content.

8. The method according to claim 1, further comprising the step of:

writing an enable value in said medium, wherein said enable value enables regeneration of second media key in each of said players.

9. The method according to claim 1, further comprising the step of:

writing said class key to a license server, wherein said license server is in communication with said players via a network.

10. The method according to claim 9, further comprising the steps of:

authenticating said particular player at said license server; and

transmitting said class key from said license server to said particular player across said network in response to passing said authenticating.

11. A method for playing an encrypted content received in a first medium, comprising the steps of:

(A) reading a media key block, a media identification value, an encrypted title key and said encrypted content from first medium with a particular player of a plurality of players, said media key block containing a set of encrypted keys;

(B) obtaining a class key from a second medium with said particular player;

(C) generating a first media key with said particular player by decrypting at least one encrypted key from said set of encrypted keys in said media key block based on a device key, wherein said device key is unique to said particular player;

(D) generating a second media key that has been assigned to one of a plurality of subscriber classes with said particular player by applying a decryption cipher to said first media key using said class key;

(E) generating a title key with said particular player by decrypting said encrypted title key based on both said second media key and said media identification value;

(F) generating a content with said particular player by decrypting said encrypted content based on said title key; and

(G) generating an output signal carrying said content with said particular player.

12. The method according to claim 11, wherein (i) said second medium comprises a smart card and (ii) said obtaining said class key comprising reading said class key from said smart card.

13. The method according to claim 12, further comprising the steps of:

reading an enable value from said smart card; and

enabling said generation of said second media key in response to said enable value.

14. The method according to claim 11, further comprising the steps of:

reading a control value from said first medium; and

controlling a plurality of permissions to use said content in response to said control value.

15. The method according to claim 11, further comprising the step steps of:

reading a protection value from said first medium; and

modifying an analog signal representation of said content in response to said protection value, to hamper copying of said content in said analog signal.

16. The method according to claim 11, further comprising the steps of:

reading an enable value from said second medium; and

enabling said generation of said second media key in response to said enable value.

17. The method according to claim 11, further comprising the step of:

authenticating said particular player at a license server, wherein (i) said second medium comprises a network and (ii) said obtaining said class key comprises receiving said class key at

said particular player from said license server over said network in response to passing said authenticating.

18. The method according to claim 11, further comprising the steps of:

reading another title key from a smart card; and

replacing said title key with said other title key.

19. The method according claim 11, further comprising the step of:

watermarking said content with a player identification value, wherein said player identification value is unique to said particular player.

20. The method according to claim 19, further comprising the steps of:

reading a card identification value of said second medium; and

embedding said card identification value in said watermarking.

21. The method according to claim 19, further comprising the steps of:

authenticating said particular player with a license server;

receiving a transaction identification value at said particular player from said license server in response to passing said authenticating; and

embedding said transaction identification value in said watermarking.

22. The method according claim 11, further comprising the steps of:

receiving a user identification value of a user of said particular player, wherein said user identification value is unique to said user; and

watermarking said content with said user identification value.

23. The method according to claim 11, further comprising the steps of:

receiving a password from a user;

authenticating said password; and

enabling said generation of said content in response to passing said authenticating.

24. A method of screening a content, comprising the steps of:

(A) receiving said content at a recorder from a source;

(B) receiving a class key at said recorder from an owner of said content;

(C) reading a media key block and a media identification value of a first medium with said recorder, said media key block containing a set of encrypted keys;

(D) generating an encrypted content with said recorder by encrypting said content based on a title key;

(E) generating a media key with said recorder based on (i) said class key, (ii) a particular key decrypted from at least one encrypted key from said set of encrypted keys in said media key block, and (iii) a device key, wherein said device key is unique to a particular player of a plurality of players;

(F) assigning said media key to one of a plurality of subscriber classes with said recorder;

(G) generating an encrypted title key by encrypting said title key based on (i) said media identification value and (ii) said media key;

(H) transferring (i) said encrypted content and said encrypted title key via said first medium and (ii) said class key via a second medium from said recorder to said particular player; and

(I) regenerating said media key with said particular player based on (i) said particular key decrypted from said at least one encrypted key from said set of encrypted keys in said media key block, (ii) said class key and (iii) said device key;

(J) regenerating said title key with said particular player based on (i) said encrypted key, (ii) said media identification value and (iii) said media key;

(K) regenerating said content with said particular player by decrypting said encrypted content based on said title key; and

(L) generating an output signal carrying said content with said particular player.

25. The method according to claim 24, further comprising the steps of:

receiving a password from a user; and

authenticating said password, wherein said generating of said content is further based on passing said authenticating.

26. The method according to claim 24, wherein said content is at least one of a video stream, an audio stream, a text document, a still image and a data file.