Content security system for screening applications

• US 20050278257A1
• Filed: 12/22/2004
• Published: 12/15/2005
• 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: Wells, Aaron G., Barr, David A.
• Granted Patent: US 7,536,355 B2
• Time in Patent Office: Days
• 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) 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 said media key by decryption based on a class key such that said 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 said media key after modification and a media identification value unique to said media; and

(D) writing an encrypted content in said media by encrypting said content based on said title key.

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

writing said class key in a smart card to enable said particular player to decrypt said media key while connected to said smart card.

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

setting an enable value in said smart card to enable modification of said 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 to enable said particular player to decrypt said encrypted content independent of said media key.

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

writing data for authenticating a password entered at said particular player in one of said media and said smart card.

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

writing a control value in said media to control a plurality of permissions in said players for use of said content.

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

writing a protection value in said media to enable an analog protection system in said players that hampers copying 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 media to enable modification of said 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 in communication with said players via a network.

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

transmitting said class key to said particular player across said network in response an authenticating said particular player.

11. A method for playing an encrypted content stored in a media, comprising 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 said media key by decryption based on a class key such that said media key is unique for each of a plurality of subscriber classes;

(C) generating a title key by decrypting an encrypted title key based on both said media key post modification and a media identification value unique to said media; and

(D) generating a content by decrypting said encrypted content based on said title key.

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

reading said class key from a smart card prior to modification of said media key.

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

enabling modification of said media key in response to an enable value stored in said smart card.

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

controlling a plurality of permissions for use of said content in response to a control value read from said media.

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

modifying an analog signal representation of said content in response to a protection value read from said media to hamper copying of said content in said analog signal.

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

enabling modification of said media key in response to an enable value read from said media.

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

receiving said class key from a license server over a network in response to authenticating said particular player.

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

replacing said title key as decrypted with another title key read from said smart card.

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

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

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

embedding an identification value for a smart card carrying said class key in said watermarking.

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

embedding a transaction identification value from an authentication with a license server in said watermarking.

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

watermarking said content with a user identification value unique to a user of said particular player.

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

authenticating a password entered by a user to enable generation of said content.

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

(A) generating an encrypted content by encrypting said content based on (i) a media identification value unique to a first media, (ii) a media key generated from a media key block of said first media and (iii) a device key unique to a particular player of a plurality of players;

(B) modifying said media key based on a class key as part of said encrypting such that said media key is unique for each of a plurality of subscriber classes;

(C) transferring said encrypted content via said first media and said class key via a second media to said particular player; and

(D) generating said content by decrypting said encrypted content based on (i) said media identification value, (ii) said media key generated from said media key block, (iii) said device key for said particular player and (iv) said class key.

25. The method according to claim 24, wherein generating said content is further based on an authenticated password entered by a user.

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.