Content security layer providing long-term renewable security

• US 20080037781A1
• Filed: 10/15/2007
• Published: 02/14/2008
• Est. Priority Date: 03/28/2001
• Status: Active Grant

• Current Assignee: Irdeto USA Incorporated (MultiChoice Group Ltd.)
• Original Assignee: Cryptography Research, Inc. (Rambus Inc.)
• Inventors: Carter, Matthew, Jun, Benjamin, Kocher, Paul, Jaffe, Joshua, Pearson, Peter
• Granted Patent: US 7,760,876 B2
• Time in Patent Office: Days
• US Class Current: 380/201
• 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 20/00166 involving measures which result in a restriction to authorised contents recorded on or reproduced from a record carrier, e.g. music or software
• CPC Class Codes: G11B 20/00173 wherein the origin of the content is checked, e.g. determining whether the content has originally been retrieved from a legal disc copy or another trusted source
• CPC Class Codes: G11B 20/0021 involving encryption or decryption of contents recorded on or reproduced from a record carrier
• CPC Class Codes: G11B 20/00246 wherein the key is obtained from a local device, e.g. device key initially stored by the player or by the recorder
• CPC Class Codes: G11B 20/00659 involving a control step which is implemented as an executable file stored on the record carrier
• CPC Class Codes: G11B 20/00818 wherein the usage restriction limits the signal quality, e.g. by low-pass filtering of audio signals or by reducing the resolution of video signals
• CPC Class Codes: G11B 20/0084 wherein the usage restriction can be expressed as a specific time or date
• CPC Class Codes: G11B 20/00884 involving a watermark, i.e. a barely perceptible transformation of the original data which can nevertheless be recognised by an algorithm
• CPC Class Codes: H04L 2209/603 Digital right managament [DRM]
• CPC Class Codes: H04L 2209/608 Watermarking
• 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
• CPC Class Codes: H04N 2005/91335 the copy protection signal being a watermark
• CPC Class Codes: H04N 2005/91342 the copy protection signal being an authentication signal
• 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
• CPC Class Codes: H04N 21/4135 external recorder interface circuits between an apparatus for recording television signals and a television receiver H04N5/775
• CPC Class Codes: H04N 21/4181 for conditional access
• CPC Class Codes: H04N 21/4325 by playing back content from the storage medium reproduction of recorded television signals H04N5/76; reproduction of recorded television signals H04N9/79
• CPC Class Codes: H04N 21/4405 involving video stream decryption
• CPC Class Codes: H04N 21/44236 : Monitoring of piracy processes or activities protecting computer platforms against harmful, malicious or unexpected behaviour or activities using intrusion detection and counter measures G06F21/566; computer virus detection and handling G06F21/56
• CPC Class Codes: H04N 21/4627 : Rights management associated to the content 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 21/8355 : 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 5/913 : for scrambling ; for copy protection

Abstract

In an exemplary embodiment, digital content is mastered as a combination of encrypted data and data processing operations that enable use in approved playback environments. Player devices having a processing environment compatible with the content'"'"'s data processing operations are able to decrypt and play the content. Players can also provide content with basic functions, such as loading data from media, performing network communications, determining playback environment configuration, controlling decryption/playback, and/or performing cryptographic operations using the player'"'"'s keys. These functions allow the content to implement and enforce its own security policies. If pirates compromise individual players or content titles, new content can be mastered with new security features that block the old attacks. A selective decryption capability can also be provided, enabling on-the-fly watermark insertion so that attacks can be traced back to a particular player. Features to enable migration from legacy formats are also provided.

Claims

1. A method for mastering digital video for secure playback on at least one of a plurality of widely distributed authorized player devices, comprising the steps of:

(a) for each of a plurality of portions of digital video, generating at least two versions of each of said portions;

(b) generating executable instructions for decoding said video, where

(i) said instructions, when processed by a player device, would automatically select at least one of said versions of each of said portions which will be output when said video is played,

(ii) said selection of said versions is based on information about said player device, and,

(iii) said instructions, when processed by a player device, would thereby embed a watermark into output video, said watermark encoding information used to select the combination of versions;

(c) combining said instructions with a compressed, encrypted representation of said video including said versions of said portions to form a combined representation; and

(d) distributing said combined representation for use by consumers.

2. The method of claim 1 where said information about said player device includes information uniquely identifying said player device, and further comprising:

(a) recovering an unauthorized copy of at least a portion of said video;

(b) determining which of said versions of said portions were selected during a playback process that produced said unauthorized copy;

(c) analyzing the result of (b) to identify said player device used to produce said unauthorized copy; and

(d) encoding additional digital video with instructions that prevent playback on said player device used to produce said unauthorized copy.

3. The method of claim 2 where said instructions in (d) are configured to:

(i) derive decryption keys for said additional video on authorized players;

(ii) not derive decryption keys when said instructions are processed on unauthorized players; and

(iii) not derive decryption keys when said instructions are processed on said player used to produce said unauthorized copy.

4. The method of claim 3 further comprising:

(a) obtaining, from a third party, results of cryptographic operations using keys included in distributed player devices; and

(b) using said results in said step (d) to control which players will be able to decode said video.

5. The method of claim 3 where said instructions differentiate between said authorized players and said unauthorized players based on the results of cryptographic operations performed by said players using secret keys that are not represented in said instructions.

6. The method of claim 1 where said information about said player device includes information identifying said player device, and further comprising:

(a) recovering an unauthorized copy of at least a portion of said video;

(b) determining which of said versions of said portions were selected during a playback process that produced said unauthorized copy; and

(c) analyzing the result of (b) to identify the specific player device used to produce said unauthorized copy.

7. An apparatus for mastering digital content, comprising:

(a) a variation generator

(i) configured to produce plural variations for a plurality of portions of said content,

(ii) where each variation is selected to avoid degrading playback quality while being detectable in copies of said content;

(b) an instruction generator, configured to produce decoding instructions for said content, where said instructions are program logic configured to

(i) analyze the playback environment to determine information identifying the playback environment; and

(ii) use said identifying information to select from among said variations, such that the decoding instructions cause the selected combination of variations to reflect said identifying information, to thereby embed in the output content said identifying information such that said playback device can be identified by analyzing the output content; and

(c) a cryptographic module configured to encrypt at least portions of the combination of said content and an output of said instruction generator to produce a secured representation of said content for distribution to consumers.

8. The apparatus of claim 7 where said content includes compressed digital video.

9. The apparatus of claim 7 where said content includes digital audio.

10. The apparatus of claim 7 where said instructions in (b) are further configured to:

(iii) prevent playback on compromised devices and other playback environments providing inadequate security; and

(iv) enable playback in authorized environments.

11. The apparatus of claim 10 where said instructions are further configured to limit the quality of playback on devices whose security is marginal.

12. The apparatus of claim 7 further comprising a disc creation device that creates disc copies having the securing representation for distribution to end consumers, such that said decoding instructions cause a host playback device which plays a published disc to itself analyze playback environment and embed output video with information identifying multiple characteristics of playback environment.

13. The apparatus of claim 7 where said identifying information uniquely identifies the specific host playback device.

14. The apparatus of claim 7 where said identifying information identifies the specific model of the host playback device.

15. A machine readable medium containing program logic integrated with digital content, where said program logic includes:

(a) interrogation instructions which are configured to cause

(i) interrogation of a system reading said signal, and

(ii) consequent generation of data characterizing the system; and

(b) output generation instructions which are configured to cause

(i) for each of a plurality of portions of said digital content, selection between different alternate versions of such portions, where such selection is performed in dependence upon data characterizing the system, and

(ii) generation of an output representation of said digital content representing only one version of each subset;

(c) where version selection for each portion with alternate versions is made dependent upon the data characterizing the system.

16. The apparatus of claim 15, wherein the program logic includes:

(a) instructions configured to use interrogation results to assess the level system security; and

(b) instructions configured to limit the quality of digital content in the output signal for systems whose security is marginal.

17. The apparatus of claim 15, where said interrogation in (a) interrogates the system to identify at least one of:

(i) system identity, (ii) results of cryptographic operations, (iii) user action descriptions, and (iv) output device information.