Content providing system, content reproducing device, content reproducing method, and computer program

• US 20070198413A1
• Filed: 03/30/2006
• Published: 08/23/2007
• Est. Priority Date: 04/07/2005
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Nagao, Yutaka
• Granted Patent: US 10,097,347 B2
• Time in Patent Office: Days
• US Class Current: 705/50
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 2209/603 Digital right managament [DRM]
• CPC Class Codes: H04L 2463/101 applying security measures for digital rights management data processing systems or methods, specially adapted for commerce, e.g. marketing, shopping, billing, auctions or e-commerce G06Q30/00
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 9/0822 using key encryption key
• CPC Class Codes: H04L 9/0894 Escrow, recovery or storing of secret information, e.g. secret key escrow or cryptographic key storage

Abstract

A content reproducing device decrypts and outputs an encrypted content encrypted by a content key received from a content transmitting device. The content reproducing device includes a content key obtaining unit for obtaining the content key, and a storage unit for storing the key unique to the content transmitting device, usage restriction information to restrict the usage of the key unique to the content transmitting device, and link information indicating linking of the content transmitting device and the content reproducing device. The content reproducing device also includes a key decryption unit for decrypting the content key with the key unique to the content transmitting device in the event that the content reproducing device is included in the stored link information unit, and a usage control unit for restricting usage of the key unique to the content transmitting device, based on the stored usage restriction information.

Claims

1. A content providing system comprising:

a content transmitting device for transmitting an encrypted content encrypted by a content key, said content transmitting device having

a device key encrypting unit configured to encrypt a device key unique to said content transmitting device with a device key unique to a content receiving device, and

a link information issuing unit configured to provide said content reproducing device with

one or a plurality of sets of link information for generating a path of which the origin is said content transmitting device and of which the destination is said content reproducing device,

said device key unique to said content transmitting device encrypted at said device key encrypting unit,

a content key encrypted with said device key unique to said content transmitting device, and

content usage restriction information;

and a content reproducing device having

a content key obtaining unit configured to obtain said content key encrypted with a key unique to said content transmitting device;

a storage unit configured to store

said key unique to said content transmitting device,

usage restriction information to restrict the usage of said key unique to said content transmitting device, and

link information indicating linking of said content transmitting device and said content reproducing device;

a content key decryption unit configured to decrypt said content key with said key unique to said content transmitting device in the event that said content reproducing device is included in said link information stored at said storage unit; and

a usage control unit configured to restrict usage of said key unique to said content transmitting device, based on said usage restriction information stored in said storage unit.

2. A content reproducing device for decrypting and outputting an encrypted content encrypted by a content key received from a content transmitting device, said content reproducing device comprising:

a content key obtaining unit configured to obtain said content key encrypted with a key unique to said content transmitting device;

a storage unit configured to store

said key unique to said content transmitting device,

usage restriction information to restrict the usage of said key unique to said content transmitting device, and

link information indicating linking of said content transmitting device and said content reproducing device;

a key decryption unit configured to decrypt said content key with said key unique to said content transmitting device in the event that said content reproducing device is included in said link information stored at said storage unit; and

a usage control unit configured to restrict usage of said key unique to said content transmitting device, based on said usage restriction information stored in said storage unit.

3. The content reproducing device according to claim 2, further comprising a key processing unit for decrypting said key unique to said content transmitting device, which has been encrypted and stored in said storage unit, using said key unique to said content transmitting device;

wherein said key processing unit is successful in decryption of said key in the event link information, in which identification information identifying said content reproducing device and identification information identifying said content transmitting device have been correlated, has been stored in said link information storage unit.

4. The content reproducing device according to claim 3, wherein said storage unit stores at least one set of link information, with correlation of said content reproducing device and said content transmitting device being realized by a path being generated, in which the origin is said content reproducing device and the destination is said content transmitting device, according to said stored link information.

5. The content reproducing device according to claim 2, wherein said usage restriction information includes decryption restriction information which restricts decryption of said content key with said key unique to said content transmitting device that is stored in said storage unit.

6. The content reproducing device according to claim 2, wherein said usage restriction information includes transmission restriction information that restricts transmission of said key unique to said content transmitting device that is stored in said storage unit to another content reproducing device.

7. The content reproducing device according to claim 4, further comprising:

a link information issuing unit configured to issue said link information to another content reproducing device; and

a device key encrypting unit configured to encrypt a device key unique to said content transmitting device with a device key unique to said other content reproducing device;

said link information issuing unit providing said other content reproducing device with

one or a plurality of sets of link information stored in said storage unit for generating a path of which the origin is said content production device identified by said identification information and of which the destination is said content transmitting device identified by said identification information,

said device key unique to said content reproducing device encrypted at said device key encrypting unit, and

said usage restriction information stored in said storage device.

8. The content reproducing device according to claim 7, further comprising a restriction information generating unit configured to generate a second usage restriction information based on usage restriction information stored in said storage unit;

wherein said link information issuing unit provides said second usage restriction information to said other content reproducing device.

9. A content transmitting device for transmitting an encrypted content encrypted by a content key to a content reproducing device, said content transmitting device comprising:

a device key encrypting unit configured to encrypt a device key unique to said content transmitting device with a device key unique to said content reproducing device; and

a link information issuing unit configured to provide said content reproducing device with

one or a plurality of sets of link information for generating a path of which the origin is said content transmitting device and of which the destination is said content reproducing device,

said device key unique to said content transmitting device encrypted at said device key encrypting unit,

a content key encrypted with said device key unique to said content transmitting device, and

content usage restriction information;

10. A content reproducing device for decrypting and outputting an encrypted content encrypted by a content key received from a content transmitting device, said content reproducing device comprising:

means for obtaining said content key encrypted with a key unique to said content transmitting device;

means for storing said key unique to said content transmitting device, usage restriction information to restrict the usage of said key unique to said content transmitting device, and link information indicating linking of said content transmitting device and said content reproducing device;

means for decrypting said content key with said key unique to said content transmitting device in the event that said content reproducing device is included in said link information stored at said storing means; and

means for restricting usage of said key unique to said content transmitting device, based on said usage restriction information stored in said storing means.

11. A content transmitting device for transmitting an encrypted content encrypted by a content key to a content reproducing device, said content transmitting device comprising:

means for encrypting a device key unique to said content transmitting device with a device key unique to said content reproducing device; and

means for providing said content reproducing device with one or a plurality of sets of link information for generating a path of which the origin is said content transmitting device and of which the destination is said content reproducing device, said device key unique to said content transmitting device encrypted at said encrypting means, and content usage restriction information.

12. A computer-readable recording medium storing a program for causing a computer to execute decrypting and outputting of an encrypted content encrypted by a content key received from a content transmitting device, with a content reproducing device, said program comprising:

code for obtaining said content key encrypted with a key unique to said content transmitting device;

code for storing

said key unique to said content transmitting device,

usage restriction information to restrict the usage of said key unique to said content transmitting device, and

link information indicating linking of said content transmitting device and said content reproducing device;

code for decrypting said content key with said key unique to said content transmitting device in the event that said content reproducing device is included in said link information stored in said storing step; and

code for restricting usage of said key unique to said content transmitting device, based on said usage restriction information stored in said storing step.

13. A computer-readable recording medium storing a program for causing a computer to execute transmitting of an encrypted content encrypted by a content key to a content reproducing device, with a content transmitting device, said program comprising:

code for encrypting a device key unique to said content transmitting device with a device key unique to said content reproducing device; and

code for providing said content reproducing device with one or a plurality of sets of link information for generating a path of which the origin is said content transmitting device and of which the destination is said content reproducing device, said device key unique to said content transmitting device encrypted in said encrypting step, and content usage restriction information.

14. A method for decrypting and outputting an encrypted content encrypted by a content key received from a content transmitting device, with a content reproducing device, said method comprising the steps of:

obtaining said content key encrypted with a key unique to said content transmitting device;

storing

said key unique to said content transmitting device,

usage restriction information to restrict the usage of said key unique to said content transmitting device, and

link information indicating linking of said content transmitting device and said content reproducing device;

decrypting said content key with said key unique to said content transmitting device in the event that said content reproducing device is included in said link information stored in said storing step; and

restricting usage of said key unique to said content transmitting device, based on said usage restriction information stored in said storing step.

15. A method for transmitting an encrypted content encrypted by a content key to a content reproducing device, with a content transmitting device, said method comprising the steps of:

encrypting a device key unique to said content transmitting device with a device key unique to said content reproducing device; and

providing said content reproducing device with one or a plurality of sets of link information for generating a path of which the origin is said content transmitting device and of which the destination is said content reproducing device, said device key unique to said content transmitting device encrypted in said encrypting step, and content usage restriction information.