Self-protecting digital content

• US 7,987,510 B2
• Filed: 07/07/2003
• Issued: 07/26/2011
• Est. Priority Date: 03/28/2001
• Status: Active Grant

• Current Assignee: Irdeto USA Incorporated (MultiChoice Group Ltd.)
• Original Assignee: Rovi Solutions Corporation (Adeia Inc.)
• Inventors: Lawson, Nathaniel J., Jun, Benjamin C., Pearson, Peter K., Laren, Carter C., Kocher, Paul C., Jaffe, Joshua M.
• Primary Examiner(s): Popham; Jeffrey D
• Application Number:
  US10/614,765
• Publication Number:
  US 20040133794A1
• Time in Patent Office: 2,941 Days
• Field of Search: 726/29
• US Class Current: 726/27
• CPC Class Codes: G06F 21/50 Monitoring users, programs or devices to maintain the integrity of platforms, e.g. of processors, firmware or operating systems
• CPC Class Codes: G06F 21/62 Protecting access to data via a platform, e.g. using keys or access control rules
• CPC Class Codes: G06F 21/6281 at program execution time, where the protection is within the operating system
• CPC Class Codes: G06F 21/78 to assure secure storage of data address-based protection against unauthorised use of memory G06F12/14; record carriers for use with machines and with at least a part designed to carry digital markings G06K19/00
• 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 20/00115 wherein the record carrier stores a unique medium identifier
• CPC Class Codes: G11B 20/0021 involving encryption or decryption of contents recorded on or reproduced from a record carrier
• CPC Class Codes: G11B 20/00231 wherein the key is obtained from a local external medium, e.g. a card
• 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 20/00253 wherein the key is stored on the record carrier
• CPC Class Codes: G11B 20/00449 content scrambling system [CSS]
• 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 20/00884 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 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 2209/60 Digital content management, e.g. content distribution
• CPC Class Codes: H04L 2209/606 Traitor tracing
• CPC Class Codes: H04L 9/3236 using cryptographic hash functions
• CPC Class Codes: H04L 9/3249 using RSA or related signature schemes, e.g. Rabin scheme
• CPC Class Codes: H04N 2005/91342 the copy protection signal being an authentication signal
• 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 21/4135 : 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 21/42646 : for reading from or writing on a non-volatile solid state storage medium, e.g. DVD, CD-ROM
• 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 21/8358 : 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

Technologies are disclosed to transfer responsibility and control over security from player makers to content authors by enabling integration of security logic and content. An exemplary optical disc carries an encrypted digital video title combined with data processing operations that implement the title'"'"'s security policies and decryption processes. Player devices include a processing environment (e.g., a real-time virtual machine), which plays content by interpreting its processing operations. Players also provide procedure calls to enable content code to load data from media, perform network communications, determine playback environment configurations, access secure nonvolatile storage, submit data to CODECs for output, and/or perform cryptographic operations. Content can insert forensic watermarks in decoded output for tracing pirate copies. If pirates compromise a player or title, future content can be mastered with security features that, for example, block the attack, revoke pirated media, or use native code to correct player vulnerabilities.

Claims

1. A non-transitory storage medium containing content with protections against unauthorized copying, the storage medium comprising:

digital signature authenticating at least an identifier of the storage medium;

a revocations list for identifying at least one revoked storage medium;

content that is encrypted by using broadcast encryption, whereby;

each of a plurality of authorized playback devices has cryptographic keys sufficient for decrypting the content, and

each of a plurality of revoked playback devices does not have keys sufficient for decrypting the content;

program logic for an interpreter of a Turing complete language, the program logic being a portion of the content and adapted for execution on a playback device in order to play another portion of the same content, the program logic being loaded with the content on the playback device, the program logic further configured for cryptographically authenticating the revocations list, the program logic further configured to perform a security check that interrogates a playback environment of the playback device and to verify at least one of;

a playback device identity, including at least one of a player serial number, specific subscriber information, a player model, or a player software version, and a user identity, including at least one of a user name, geographical region, email address, or a web address, the program logic further configured to reduce output quality if a result of the interrogation of the playback environment is uncertain;

a plurality of versions for each of a plurality of portions of the content, wherein;

said versions for each portion are distinguished from each other,

said versions are encrypted with different keys, such that each of said authorized playback devices is capable of deciphering at least one, but not all, of said versions for each of said portions, and

the combination of said portions decipherable by a given player being usable to identify said player, the program logic being further configured to provide a correct set of decryption keys for decrypting each of said versions decipherable by a given player, at least one decryption key of the set of decryption keys for decrypting a corresponding one of said versions decipherable by a given player; and

interface logic defining an interface usable to interact with a user and to control playback of the content by using the program logic.

2. The medium of claim 1, wherein:

said program logic is configured to perform a plurality of security checks; and

said program logic is configured to permit playback of the content provided that said plurality of security checks is successful.

3. The medium of claim 2 wherein said program logic is configured to invoke at least one cryptographic operation supported by at least one of said authorized playback devices.

4. The medium of claim 2 wherein said program logic is configured to perform at least one operation necessary for decryption of the content by at least one said authorized playback device.

5. The medium of claim 2, wherein the program logic that is configured to perform a plurality of security checks generates a security check result, the security check result for embedding into content rendered by a playback device on which the security checking is performed.

6. The medium of claim 1 wherein a subset of said authorized playback devices encompass a plurality of models, each model having a model-specific vulnerability, and the medium further comprising program logic which, when executed by a device of each said vulnerable model, is configured to:

mitigate said vulnerability affecting said vulnerable playback device; and

perform at least one operation necessary for said vulnerable playback device to decrypt said content.

7. The medium of claim 6 wherein said program logic includes executable code for a Turing-complete virtual machine.

8. The medium of claim 6 wherein said operation necessary to decrypt includes updating a cryptographic key contained in said playback device.

9. The medium of claim 6 wherein said program logic for mitigating includes native executable code configured to detect whether security of a vulnerable device has been compromised.

10. The medium of claim 6 wherein said program logic for mitigating includes native executable code configured to correct a vulnerability in a vulnerable device.

11. The medium of claim 6 wherein said program logic for mitigating includes a firmware upgrade for correcting at least one vulnerability.

12. The medium of claim 1, wherein the program logic is adapted to perform at least one security check, the at least one security check to verify a result of cryptographic processing adapted to fail a verification operation if executed on at least one of an unauthorized or revoked or compromised playback device.

13. A device for securely playing content, the content including a plurality of regions each having multiple versions thereof, the device comprising:

a media reader for use in reading data from a storage medium;

a nonvolatile memory containing;

a set of cryptographic player keys for use with a broadcast encryption system, and identifiers of revoked media;

a bulk decryption module for decrypting encrypted content from the storage medium;

a Turing-complete interpreter for executing program logic, the program logic being a portion of the content and configured to;

load with the content from the media reader, the program logic being adapted for execution on the device in order to play another portion of the same content on the device;

cryptographically authenticate identifiers of revoked media;

interrogate a playback environment of the device and to verify at least one of;

a device identity, including at least one of a player serial number, specific subscriber information, a player model, or a player software version, and a user identity, including at least one of a user name, geographical region, email address, or a web address, the program logic further configured to reduce output quality if a result of the interrogation of the playback environment is uncertain;

verify whether digital signatures contained on the storage medium authenticate the storage medium;

verify whether the storage medium is identified as revoked in said nonvolatile memory;

select a version of each of the plurality of regions, thereby generating a set of selected versions;

provide a correct set of decryption keys for decrypting each of said selected versions, at least one decryption key of the set of decryption keys for decrypting a corresponding one of said versions; and

decrypt said selected version, whereby a combination of said versions selected in the course of playing content from the storage medium uniquely identifies said device; and

at least one codec for decoding content.

14. The device of claim 13, wherein said interpreter is configured to obtain said program logic from said media reader for loading on the device.

15. The device of claim 13 further comprising means for reducing during a rendering process the output quality of said audiovisual content in dependence upon whether a security requirement specified by the storage medium for high-quality output is met.

16. The device of claim 13 wherein:

said set of cryptographic player keys is unique to the device; and

said program logic is configured to select a unique set of versions by using said unique set of cryptographic player keys.

17. The device of claim 13 wherein the program logic being configured to forego decryption of the selected version if the program logic identifies said media as revoked.

18. A method for playing encrypted content from a storage medium, the method comprising:

verifying a digital signature for authenticating said medium;

retrieving at least one player key from a nonvolatile memory;

using said at least one player key with a broadcast encryption system;

using a result of said broadcast encryption system to decrypt at least a portion of the content;

reading program logic for a Turing-complete interpreted language from the medium, the program logic being a portion of the content, the program logic being adapted for execution on a media player device in order to play another portion of the same content on the media player device;

using an interpreter to execute said program logic, wherein said interpreter performs operations specified in said program logic including;

cryptographically authenticating identifiers of revoked media;

interrogating a playback environment of the device and to verify at least one of;

a

device identity, including at least one of a player serial number, specific subscriber information, a player model, or a player software version, and a user identity, including at least one of a user name, geographical region, email address, or a web address, the program logic further configured to reduce output quality if a result of the interrogation of the playback environment is uncertain;

verifying whether digital signatures contained on the medium authenticate the medium;

verifying whether the medium is identified as revoked in said nonvolatile memory;

selecting a variant from a plurality of variants for each of a plurality of portions of the content, wherein;

said media player device for decrypting said selected variant; and

said media player device lacks at least one cryptographic key required to decrypt at least one non-selected variant for each portion;

providing a correct set of decryption keys for decrypting each selected variant, at least one decryption key of the set of decryption keys for decrypting a corresponding one of said selected variants; and

decrypting each selected variant by using the provided correct set of decryption keys.

19. The method of claim 18 wherein said interpreter performs operations specified in said program logic to respond to selections from a user, said user selections include button presses on a remote control.

20. The method of claim 18 wherein said program logic directs said player to perform an AES block cipher operation via said interpreter.

21. The method of claim 18 further comprising accessing a media revocations list to determine whether said medium has been revoked.

22. The method of claim 18 wherein said program logic performs at least one security check of a player device seeking to play said content, the at least one security check adapted to verify a result of cryptographic processing adapted to fail a verification operation if executed on at least one of an unauthorized or revoked or compromised player, and to inhibit at least one of full quality playback or reduced quality playback if at least one security check fails.