System and method for distributing digital works, apparatus and method for reproducing digital works, and computer program product

• US 20040255138A1
• Filed: 04/30/2004
• Published: 12/16/2004
• Est. Priority Date: 07/29/1998
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Nakae, Masayuki
• Granted Patent: US 7,523,303 B2
• Time in Patent Office: Days
• US Class Current: 713/193
• 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 20/045 using payment protocols involving tickets
• CPC Class Codes: G06Q 20/123 Shopping for digital content
• CPC Class Codes: G06Q 20/1235 with control of digital rights management [DRM]

Abstract

An editing apparatus generates a capsular work in which usage conditions for each of plural usages and usage secret information, obtained by encrypting a decryption key of encrypted work data with ticket keys which differ depending on usage from each other, are encapsulated together with the encrypted work data. A ticket server apparatus, which manages the usage conditions and the ticket keys, issues a ticket containing a ticket key in the case of allowing a user to practice the usage requested by the user. A distribution center apparatus, which manages the capsular work, distributes the capsular work in accordance with the user'"'"'s request. An audiovisual apparatus acquires the capsular work from the distribution center apparatus and requests the ticket necessary to make use of the capsular work from the ticket server apparatus. The audiovisual apparatus decrypts the encrypted work data contained in the capsular work and reproduces the work data only in the case where the audiovisual apparatus has acquired the ticket.

Claims

1. A computer program product, including a computer usable medium having computer readable programs embodied therein for computer execution to achieve a digital work distribution system for distributing digital works from at least one source computer source over a computer network to a user computer, comprising:

usage condition setting means for setting conditions for plural usages of work data to be distributed by a host computer source connected to a computer network;

work encrypting means for encrypting, by the host computer source, said work data with a predetermined encryption key;

ticket key generating means for generating, by the host computer source, different ticket encryption keys and their corresponding ticket decryption keys, each of said ticket encryption keys and its corresponding one of said ticket decryption keys being associated with conditions for one usage among the conditions for the plural usages which have been set by said usage condition setting means;

decryption key encrypting means for encrypting, by the host computer source, a predetermined decryption key corresponding to said predetermined encryption key, by using each of said ticket encryption keys generated each in association with the conditions for one of the plural usages by said ticket key generating means;

encapsulating means for encapsulating, by the host computer source, said work data and said predetermined decryption key which said decryption key encrypting means has encrypted using each of said ticket encryption keys generated each in association with the conditions for one of the plural usages, and for generating a capsular work which contains said work data and said predetermined decryption key;

usage condition storing means for storing within the host computer source, in association with each other, the conditions for the plural usages which have been set by said usage condition setting means and said ticket decryption keys corresponding to said ticket encryption keys generated each in association with the conditions for one of the plural usages and used to encrypt said predetermined decryption key;

ticket decryption key encrypting means for encrypting, by the host computer source, in reply to an external request for use of said work data by a user computer connected to the computer network, a ticket decryption key which is associated with the conditions for one usage corresponding to the request among said ticket decryption keys stored in said usage condition storing means; and

ticket distribution means for distributing, by the host computer source, the ticket decryption key encrypted by said ticket decryption key encrypting means to a requester who has made the request for use of said work data.

6. The computer program product according to claim 1, wherein said host computer source comprises a first computer and a second computer connected to the network.

2. A digital work distribution system for distributing digital works to a user computer, comprising first and second computers which are connected to each other and to the user computer via a network and each of which has a memory and a central processing unit, wherein said first computer executes a program to perform:

setting conditions for plural usages of work data to be distributed;

encrypting said work data with a predetermined encryption key;

generating different ticket encryption keys and their corresponding ticket decryption keys, each of said ticket encryption keys and its corresponding one of said ticket decryption keys being associated with conditions for one usage among the set conditions for the plural usages;

encrypting a predetermined decryption key corresponding to said predetermined encryption key, by using each of said ticket encryption keys generated each in association with the conditions for one of the plural usages; and

encapsulating said work data and said predetermined decryption key encrypted using each of said ticket encryption keys generated each in association with the conditions for one of the plural usages, and generating a capsular work which contains said work data and said predetermined decryption key; and

said second computer executes a program to perform;

storing, in association with each other, the conditions for the plural usages which have been set by said first computer and said ticket decryption keys corresponding to said ticket encryption keys generated each in association with the conditions for one of the plural usages and used to encrypt said predetermined decryption key;

encrypting, in reply to an external request for use of said work data received over the network from a user computer, a ticket decryption key which is associated with the conditions for one usage corresponding to the request among the stored ticket decryption keys; and

distributing the encrypted ticket decryption key to a requester at the user computer who has made the request for use of said work data.

3. The digital work distribution system according to claim 2, wherein said predetermined encryption key and said predetermined decryption key corresponding thereto are an identical key adopting a common cryptographic system.

4. The digital work distribution system according to claim 3, wherein a common cryptographic key which is a random number is used for encryption and decryption of said capsular work.

5. The digital work distribution system according to claim 2, wherein each of said ticket encryption keys and its corresponding one of said ticket decryption keys are an identical key adopting a common cryptographic system.

7. The digital work distribution system according to claim 2, wherein said first computer further performs:

generating charging modules to effect processing of making a charge for the work data to be distributed, each of said charging modules being associated with the conditions for one of the plural usages;

further encapsulating, in said capsular work, said charging modules generated each in association with the conditions for one of the plural usages; and

said second computer further performs;

storing pieces of charging module identification for identifying said charging modules, in association with the conditions for the plural usages.

8. The digital work distribution system according to claim 2, further comprising a third computer which is connected to the network and which has a memory and a processor, wherein said third computer performs:

acquiring said capsular work generated by said first computer;

acquiring a ticket decryption key corresponding to a ticket encryption key associated with the conditions for a desired one of the plural usages and contained in the acquired capsular work;

decrypting, with the acquired ticket decryption key, the encrypted decryption key contained in said capsular work;

decrypting said work data contained in said capsular work by using the decrypted decryption key; and

reproducing the decrypted work data.

9. A digital work reproduction apparatus for reproducing digital works, comprising an input section, an output section, a memory which stores a predetermined program, and a central processing unit, wherein said central processing unit executes the predetermined program, stored in said memory, for performing:

acquiring a capsular work in which work data encrypted with a predetermined encryption key, and a predetermined decryption key encrypted with each of different ticket encryption keys associated each with conditions for one of plural usages of said work data, are encapsulated;

acquiring a ticket decryption key corresponding to a ticket encryption key associated with the conditions for a desired one of the plural usages and contained in the acquired capsular work;

decrypting, with the acquired ticket decryption key, the encrypted predetermined decryption key contained in said capsular work;

decrypting, with the decrypted predetermined decryption key, said work data contained in said capsular work; and

reproducing the decrypted work data.

10. A digital work distribution method for distributing digital works between at least one host computer source and a requester computer communicating via a network, comprising:

with at least one host computer source connected to a network setting conditions for plural usages of work data to be distributed,

encrypting said work data with a predetermined encryption key;

generating different ticket encryption keys and their corresponding ticket decryption keys, each of said ticket encryption keys and its corresponding one of said ticket decryption keys being associated with the set conditions for one of the plural usages;

encrypting a predetermined decryption key corresponding to said predetermined encryption key, by using each of said ticket encryption keys generated each in association with the conditions for one of the plural usages;

encapsulating said work data and said predetermined decryption key encrypted using each of said ticket encryption keys associated each with the conditions for one of the plural usages, and generating a capsular work which contains said work data and said predetermined decryption key;

storing, in association with each other, the set conditions for the plural usages and said ticket decryption keys corresponding to said ticket encryption keys generated each in association with the conditions for one of the plural usages and used to encrypt said predetermined decryption key;

encrypting, in reply to an external request for use of said work data received over the network from a requester computer, a ticket decryption key which is associated with the conditions for one usage corresponding to the request among the stored ticket decryption keys; and

distributing the encrypted ticket decryption key to the requester computer who has made the request for use of said work data.

11. A digital work reproduction method for reproducing digital works, comprising:

acquiring a capsular work in which work data encrypted with a predetermined encryption key, and a predetermined decryption key corresponding to said predetermined encryption key and encrypted with each of different ticket encryption keys associated each with conditions for one of plural usages of said work data, are encapsulated;

acquiring a ticket decryption key corresponding to a ticket encryption key associated with the conditions for a desired one of the plural usages and contained in the acquired capsular work;

decrypting, with the acquired ticket decryption key, the encrypted predetermined decryption key contained in said capsular work;

decrypting, with the decrypted predetermined decryption key, said work data contained in said capsular work; and

reproducing the decrypted work data.

12. A computer program product, including a computer usable medium having a computer readable program embodied therein for executing:

storing, in association with each other, conditions for plural usages of work data and ticket decryption keys which correspond to ticket encryption keys associated each with conditions for one of the plural usages and used to encrypt a decryption key of said work data encrypted;

encrypting, in reply to an external request for use of said work data, the external request being received from a network-connected requester external computer, a ticket decryption key which is associated with the conditions for one usage corresponding to the request among the stored ticket decryption keys; and

distributing the encrypted ticket decryption key to the requester computer who has made the request for use of said work data.

13. A computer program product, including a computer usable medium having a computer readable program embodied therein for executing:

acquiring a capsular work in which work data encrypted with a predetermined encryption key, and a predetermined decryption key corresponding to said predetermined encryption key and encrypted using each of different ticket encryption keys associated with conditions for plural usages of said work data, are encapsulated;

acquiring a ticket decryption key corresponding to a ticket encryption key which is associated with the conditions for a desired one of the plural usages and which is contained in the acquired capsular work;

decrypting, with the acquired ticket decryption key, the predetermined decryption key encrypted using said ticket encryption keys and contained in said capsular work;

decrypting said work data contained in said capsular work by using the decrypted predetermined decryption key; and

reproducing the decrypted work data.

14. A computer program signal embodied in a carrier wave comprising:

a usage condition setting segment which sets conditions for plural usages of work data to be distributed;

a work encrypting segment which encrypts said work data with a predetermined encryption key;

a ticket key generating segment which generates different ticket encryption keys and their corresponding ticket decryption keys, each of said ticket encryption keys and its corresponding one of said ticket decryption keys being associated with conditions for one usage among the conditions for the plural usages which have been set by said usage condition setting segment;

a decryption key encrypting segment which encrypts a predetermined decryption key corresponding to said predetermined encryption key, by using each of said ticket encryption keys generated each in association with the conditions for one of the plural usages;

an encapsulating segment which encapsulates said work data and said predetermined decryption key encrypted using each of said ticket encryption keys generated each in association with the conditions for one of the plural usages, and which generates a capsular work containing said work data and said predetermined decryption key;

a charging module generating segment which generates charging modules to effect processing of making a charge for the work data to be distributed, each of said charging modules being associated with the conditions for one of the plural usages; and

an encapsulating segment which further encapsulates, in said capsular work, said charging modules generated each in association with the conditions for one of the plural usages by said charging module generating segment.