APPARATUS, METHOD, AND COMPUTER PROGRAM PRODUCT FOR RECORDING CONTENT

Abstract

A content recording apparatus includes a key selecting unit that selects an encryption key for performing an encrypting process to adjunct data from pieces of information recorded on a recording medium, when a user generates the adjunct data which is data derived from a title content, wherein the recording medium records thereon a title key for encrypting the title content as program content and content data including the title content encrypted by the title key. The content recording apparatus also includes an encryption processing unit that performs an encrypting process to the adjunct data by the selected encryption key; and a recording unit that records the adjunct data to which the encryption process is performed and the selected encryption key in the recording medium.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a functional configuration of a DVD recorder according to a first embodiment;

FIG. 2 is a view showing data structures of AV content, a title key file, and a management file;

FIG. 3 is a flowchart showing an adjunct data generating process according to the first embodiment;

FIG. 4 is a view showing a data structure of an encapsulated file;

FIG. 5 is an explanatory view showing title key selection;

FIG. 6A is a flowchart showing a key selecting process according the first embodiment;

FIG. 6B is a flowchart showing a key selecting process according to a modification of the first embodiment;

FIG. 7 is a schematic view showing a state in which plural key numbers are set to AV content #1;

FIG. 8 is a flowchart showing a title key moving process according to the first embodiment;

FIG. 9 is a flowchart showing an adjunct data play back process according to the first embodiment;

FIG. 10 is a flowchart showing an AV content play back process according to the first embodiment;

FIG. 11 is a block diagram showing a functional configuration of a DVD recorder according to a second embodiment;

FIG. 12 is a flowchart showing a key selecting process according the second embodiment; and

FIG. 13 is a flowchart showing a key selecting process according a modification of the second embodiment.

Claims

1. A content recording apparatus comprising: a key selecting unit that selects an encryption key for performing an encrypting process to adjunct data from pieces of information recorded on a recording medium, when the apparatus generates the adjunct data which is data derived from a title content, wherein the recording medium records thereon a title key for encrypting the title content and content data including the title content encrypted by the title key;an encryption processing unit that performs an encrypting process to the adjunct data by the selected encryption key; anda recording unit that records the adjunct data to which the encryption process is performed and the selected encryption key in the recording medium.

2. The apparatus according to claim 1, wherein the content data further includes copy control information indicating presence or absence of copy restriction on the title content, and the key selecting unit selects the encryption key based on the copy control information of the title content from which the adjunct data is derived.

3. The apparatus according to claim 2, further comprising a judgment unit that judges the copy control information of the title content which is encrypted by the title key and includes the adjunct data, wherein the key selecting unit selects the encryption key as the title key corresponding to the title content including the adjunct data when the copy control information indicates copy prohibition,the encryption processing unit performs the encrypting process to the adjunct data by the selected title key, andthe recording unit records the adjunct data to which the encrypting process is performed by the encryption processing unit and the selected title key in the recording medium.

4. The apparatus according to claim 3, wherein the key selecting unit selects the encryption key as the title key corresponding to the title content including the adjunct data, when the copy control information indicates “Copy Never” or “No More Copies”.

5. The apparatus according to claim 3, wherein the encryption processing unit does not perform the encrypting process to the adjunct data, when the title content is judged to be a plaintext based on the judgment of the copy control information, and the recording unit records the unencrypted adjunct data, when the title content is judged to be a plaintext based on the judgment of the copy control information.

6. The apparatus according to claim 5, wherein the encryption processing unit does not perform the encrypting process to the adjunct data, when the copy control information indicates “Copy Free”, and the recording unit records the unencrypted adjunct data, when the copy control information indicates “Copy Free”.

7. The apparatus according to claim 3, wherein the plurality of title content, a title key file which registers the plurality of title keys corresponding to the plurality of title content respectively, and an adjunct data title key file which registers the title key used in encrypting the adjunct data are further recorded on the recording medium, and the recording unit updates the adjunct data title key file by registering the selected title key in the adjunct data title key file.

8. The apparatus according to claim 2, wherein the key selecting unit newly generates an encryption key used in performing the encrypting process to the adjunct data based on the copy control information of the title content including the adjunct data, the encryption processing unit performs the encrypting process to the adjunct data by the newly generated encryption key, andthe recording unit records the adjunct data to which the encrypting process is performed and the generated encryption key in the recording medium.

9. The apparatus according to claim 8, wherein the key selecting unit newly generates an encryption key used in performing the encrypting process to the adjunct data, when the title content including the adjunct data is encrypted and, at the same time, the copy control information of the title content indicates copy is permitted.

10. The apparatus according to claim 9, wherein the key selecting unit newly generates an encryption key used in performing the encrypting process to the adjunct data, when the title content including the adjunct data is encrypted and, at the same time, the copy control information of the title content indicates “EPN (Encryption Plus Non-assertion)” or “Copy One Generation”.

11. The apparatus according to claim 9, wherein the plurality of title content, and a title key file which registers the plurality of title key corresponding to the plurality of title content respectively are further recorded on the recording medium, and the recording unit additionally records the newly generated encryption key as the title key in the title key file.

12. The apparatus according to claim 9, further comprising a setting information storage unit that stores setting information indicating a type of a key used as the encryption key, wherein the key selecting unit encrypts the adjunct data by the title key corresponding to the title content from which the adjunct data is derived, when the setting information indicates use of the title key of the title content from which the adjunct data is derived.

13. The apparatus according to claim 12, wherein the key selecting unit generates the new encryption key to perform the encrypting process to the adjunct data by the newly generated encryption key, when the setting information indicates that the title key of the title content from which the adjunct data is derived is not used.

14. The apparatus according to claim 9, wherein the plurality of title content, a title key file which registers the plurality of title keys corresponding to the plurality of title content and the adjunct data respectively, and an adjunct data title key file which registers the plurality of title key used in encrypting the adjunct data are further recorded on the recording medium, and the recording unit additionally records the newly generated encryption key as the title key in the adjunct data title key file.

15. The apparatus according to claim 1, wherein the recording unit records the adjunct data to which the encrypting process is performed by the encryption processing unit and key information on the selected encryption key in the recording medium as a single file.

16. A content recording method comprising: selecting an encryption key for performing an encrypting process to adjunct data from pieces of information recorded on a recording medium, when generating the adjunct data which is data derived from a title content, wherein the recording medium records thereon a title key for encrypting the title content and content data including the title content encrypted by the title key;performing an encrypting process to the adjunct data by the selected encryption key; andrecording the adjunct data to which the encryption process is performed and the selected encryption key in the recording medium.

17. A computer program product having a computer readable medium including programmed instructions for recording content, wherein the instructions, when executed by a computer, cause the computer to perform: selecting an encryption key for performing an encrypting process to adjunct data from pieces of information recorded on a recording medium, when generating the adjunct data which is data derived from a title content, wherein the recording medium records thereon a title key for encrypting the title content and content data including the title content encrypted by the title key;performing an encrypting process to the adjunct data by the selected encryption key; andrecording the adjunct data to which the encryption process is performed and the selected encryption key in the recording medium.