Access control for digital content

• US 7,461,406 B2
• Filed: 07/30/2004
• Issued: 12/02/2008
• Est. Priority Date: 07/31/2003
• Status: Expired due to Fees

• Current Assignee: Sony United Kingdom Limited (Sony Group Corp.)
• Original Assignee: Sony United Kingdom Limited (Sony Group Corp.)
• Inventors: Tapson, Daniel Warren, Pelly, Jason Charles, Hooper, Daniel Luke, Taylor, Andrew Robert, Alves-Moreira, Emmanuel
• Primary Examiner(s): Simitoski; Michael J
• Application Number:
  US10/903,266
• Publication Number:
  US 20050180573A1
• Time in Patent Office: 1,586 Days
• Field of Search: 713/172, 726/27, 726/31, 726/33, 380/200, 380/285, 705/55, 705/59
• US Class Current: 726/27
• CPC Class Codes: G06F 21/1014 to tokens
• CPC Class Codes: G06F 21/109 by using specially-adapted hardware at the client
• CPC Class Codes: G06F 21/16 Program or content traceability, e.g. by watermarking
• 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 20/00347 wherein the medium identifier is used as a key
• CPC Class Codes: G11B 20/00492 wherein content or user data is encrypted
• CPC Class Codes: G11B 20/00536 wherein encrypted content data is subjected to a further, iterated encryption, e.g. interwoven encryption
• 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: G11B 2220/17 Card-like record carriers
• CPC Class Codes: G11B 2220/2537 Optical discs
• CPC Class Codes: G11B 2220/90 Tape-like record carriers
• CPC Class Codes: H04L 2209/60 Digital content management, e.g. content distribution
• CPC Class Codes: H04L 9/0836 using tree structure or hierarchical structure
• CPC Class Codes: H04L 9/0894 Escrow, recovery or storing of secret information, e.g. secret key escrow or cryptographic key storage
• CPC Class Codes: H04N 2005/91364 the video signal being scrambled
• CPC Class Codes: H04N 5/772 the recording apparatus and the television camera being placed in the same enclosure
• CPC Class Codes: H04N 5/913 for scrambling ; for copy protection

Abstract

A recording system for applying access control processing to input data content and for recording access-controlled data content on a computer readable storage medium. The recording system includes an encryption apparatus for encrypting portions of the input data content and an access control memory device which securely stores information from which a private key of a public key/private key pair associated with a data content recording user or user group is derivable. The encryption apparatus and the access control memory device co-operate to provide access control data including content recorder access control data and default access control data. The default content access control data provides the same level of access to the input data content as the level of access available to the data content recording user/user group. A recorder is provided for recording the encrypted input data content and the content access control data on the computer readable storage medium.

Claims

1. A recording system configured to apply access control processing to input data content using a set of one or more content keys and to record access-controlled data content on a computer readable storage medium, said recording system comprising:

an encryption apparatus having encryption logic configured to encrypt portions of said input data content in dependence upon said set of content keys to generate encrypted input data content;

an access control memory device configured to store securely information from which a private key of a private key/public key pair associated with a data content recording user or user group is derivable, said encryption apparatus and said access control memory device co-operating to provide a content access control data generator configured to generate content access control data, said content access control data including at least one encrypted version of a respective subset of said set of content keys, said content access control data including content recorder access control data and default access control data, said content recorder access control data being generated in dependence upon the public key corresponding to the private key derivable from information stored on said access control memory device and said default access control data being generated in dependence upon one or more public keys of respective default public key/default private key pairs defined as default public keys in said access control memory device, said default access control data providing the same level of access to said input data content via one of said default private keys as the level of access available to said data content recording user or user group, said content access control data generator configured to always encrypt the full set of content keys using the one or more default public keys,

wherein said encryption apparatus is configured to record said encrypted input data content on said computer readable storage medium together with said content recorder access control data and said default access control data.

2. The recording system according to claim 1, wherein said encryption logic is configured to apply a symmetric encryption to portions of said input data content using said set of one or more content keys.

3. The recording system according to claim 1, wherein said content access control data generator is configured to symmetrically encrypt said at least one subset of the set of one or more content keys using a content session key and to asymmetrically encrypt the content session key using the public key of a respective public key/private key pair.

4. The recording system according to claim 1, wherein said content access control data generator is configured to asymmetrically encrypt said at least one subset of said set of one or more content keys using the public key of a respective public key/private key pair.

5. The recording system according to claim 1, wherein said encryption apparatus further includes logic to generate said set of one or more content keys.

6. The recording system according to claim 1, wherein at least one of said access control memory device and said encryption apparatus further includes memory for storing public keys associated with a respective plurality of access control memory devices.

7. The recording system according to claim 1, wherein said access control memory device stores public keys associated with private keys held by other access control memory devices.

8. The recording system according to claim 1, wherein said access control memory device is a removable memory device and said encryption apparatus further includes an interface configured to provide a secure data connection between said encryption apparatus and said removable memory device.

9. The recording system according to claim 8, wherein said encryption apparatus further includes memory for storing a plurality of public keys associated with a respective plurality of removable memory devices and said removable memory device is configured to store identification data associating that removable memory device with a respective public key held by said encryption apparatus.

10. The recording system according to claim 8, wherein said removable memory device further includes a data processing module configured to perform encryption on said input data content and/or for the purpose of generating said content access control data.

11. The recording system according to claim 8, wherein said removable memory device is a smart card.

12. The recording system according to claim 8, wherein said removable memory device is a secure digital card.

13. The recording system according to claim 1, wherein said encryption apparatus further includes an audio and/or video capture or processing apparatus.

14. The recording system according to claim 1, wherein said input data content includes video images and said encryption logic is configured to apply at least one of symmetric encryption, asymmetric encryption and visible watermarking to said video images.

15. A recording system configured to process input data content using a set of one or more content keys and to record access-controlled data content on a computer readable storage medium, said recording system comprising:

a removable access control memory device;

encryption logic configured to encrypt portions of said input data content in dependence upon said set of content keys to generate encrypted input data content;

an interface configured to provide a secure data connection between said encryption logic and said removable access control memory device,

said access control memory device being connectable to said encryption apparatus via said interface and configured to store securely, information from which a private key of a private key/public key pair associated with a data content recording user or user group is derivable; and

a content access control data generator configured to generate content access control data, said content access control data including at least one encrypted version of a respective subset of said set of content keys, said content access control data including content recorder access control data and default access control data, said content recorder access control data being generated in dependence upon the public key corresponding to the private key derivable from information stored on said access control memory device and said default access control data being generated in dependence upon one or more public keys of respective default public key/default private key pairs defined as default public keys in said access control memory device, said default access control data configured to provide the same level of access to said input data content via one of said default private keys as the level of access available to said data content recording user or user group, said content access control data generator configured to always encrypt the full set of content keys using the one or more default public keys,

wherein said apparatus is configured to record said encrypted input data content on said computer readable storage medium together with said content recorder access control data and said default access control data.

16. A recording method for applying access control processing to input data content using a set of one or more content keys and recording access-controlled data content on a computer readable storage medium, said recording method comprising:

encrypting portions of said input data content in dependence upon said set of content keys to generate encrypted input data content;

securely storing information from which a private key of a private key/public key pair associated with a data content recording user or user group is derivable;

generating content access control data including at least one encrypted version of a respective subset of said set of content keys, said content access control data including content recorder access control data and default access control data, said content recorder access control data being generated in dependence upon a public key corresponding to a private key derivable from information stored on an access control memory device and said default access control data being generated in dependence upon one or more public keys of respective default public key/default private key pairs defined as default public keys in said access control memory device, said default access control data configured to provide the same level of access to said input data content via one of said default private keys as the level of access available to said data content recording user or user group, said full set of content keys always encrypted using the one or more default public keys; and

recording said encrypted input data content on said computer readable storage medium together with said content recorder access control data and said default access control data.

17. A computer readable storage medium in which a program is recorded, said program executing a method comprising:

encrypting portions of input data content in dependence upon a set of content keys to generate encrypted input data content;

securely storing information from which a private key of a private key/public key pair associated with a data content recording user or user group is derivable;

generating content access control data including at least one encrypted version of a respective subset of said set of content keys, said content access control data including content recorder access control data and default access control data, said content recorder access control data being generated in dependence upon a public key corresponding to a private key derivable from information stored on an access control memory device and said default access control data being generated in dependence upon one or more public keys of respective default public key!default private key pairs defined as default public keys in said access control memory device, said default access control data configured to provide the same level of access to said input data content via one of said default private keys as the level of access available to said data content recording user or user group, said full set of content keys always using the one or more default public keys; and

recording said encrypted input data content on said computer readable storage medium together with said content recorder access control data and said default access control data.