JP2007102450A - Content recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that when the maximum number of storage content is increased from conventional specifications, processing capability required for equipment is increased. <P>SOLUTION: In a content recording medium 10 equipped with a user data region 11 and a protect region 12, a plurality of first content databases 15 and a second content database 13 including one content database management part 14 are stored in the user data region 11, and the attribute information of the content to be managed by all the plurality of first content databases 15 are associated with the content so as to be managed by the content database managing part 14, and an encryption key 16 is stored in the protect region 12. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a recording medium for storing content data and an encryption key for encrypting the content data.

  In recent years, businesses dealing with digital content such as electronic content distribution are expanding, and expectations for technology for distributing paid digital content are increasing. In electronic content distribution, a user purchases content through a network such as the Internet, and can download and view content data on his / her personal computer. In most cases, purchased content data cannot be freely copied from a personal computer, and some copy protection mechanism such as encryption is incorporated.

  When music content or video content is purchased, it is generally recorded in a removable recording medium and viewed on a portable device instead of a personal computer. A typical recording medium used at this time is a semiconductor memory card.

  Semiconductor memory cards are known as flash ATA cards and SD memory cards. These semiconductor memory cards have a built-in semiconductor device called a flash memory (EEPROM), and can write data at a higher speed than MD, CD-R, etc., and store a huge amount of content data in a short time. It can be completed with.

  Similarly, when storing purchased music content or video content in a semiconductor memory card, measures for preventing unauthorized copying such as encryption are taken. The following has been proposed as one of means for realizing copyright protection of content in a semiconductor memory card (see Patent Document 1). Only when the validity of the connected device is authenticated in the semiconductor memory card, the protected area that can be accessed by the device, and whether or not the device is authenticated. Two unprotected areas that can be accessed are provided. The content data is encrypted and stored in the unprotected area, and the encryption key used for encryption is stored in the protected area. As a result, since the encryption key cannot be obtained unless it is a legitimate device, unauthorized copying can be prevented.

  As an application example using the above-described conventional technology, an audio device stored in a semiconductor memory card is standardized, and an application device corresponding to the standard can be considered. Since the content stored in the semiconductor memory card needs to be reproducible between various compatible devices, the device conforms to the standard, and the content can be shared between the standard-compliant devices. In that case, in order to prevent the problem that the processing capability of the corresponding device is insufficient, it is normal to define the maximum number of contents that can be stored in the semiconductor memory card by the standard.

  For example, assuming that the maximum size of a semiconductor memory card assumed as a standard is 2 GB (gigabytes), the bit rate of audio content to be stored is 128 kbps, and the length of one audio content is 4 minutes, 2 GB / 128 kbps / 4 minutes = Since it is 546.1, it is conceivable to define a standard capable of storing up to about 1000 audio contents with a margin. The compatible device can be designed to handle a maximum of 1000 contents, so that it is not necessary to have an unnecessarily high processing capability.

However, in recent years, the capacity and the price of flash memories have been increased, and the capacity of semiconductor memory cards has been rapidly expanding. For this reason, the appearance of semiconductor memory cards exceeding the capacity initially assumed by the standard is predicted, and it is clear that the current standard will be unsatisfactory.
Japanese Patent No. 3425119

  In this situation, the above prior art has the following problems. If a new standard that simply expands the number of contents that can be stored simply by using the above-described conventional technology is specified, the processing capability required for the device increases in proportion to the expanded number. For example, when the number of contents stored is increased by ten times, the processing capability required for the device up to now is required for the device corresponding to the new standard.

  A content recording medium according to the present invention is a content recording medium including a user data area and a protect area, and the user data area is determined by the device regardless of whether or not the validity of the connected device is authenticated. The protected area is an area that can be accessed by the device only when the mutual validity is authenticated between the connected device and the content recording medium. The user data area includes a plurality of protected areas. A first content database and a second content database including one content database management unit, and the content database management unit stores attribute information of content managed in the plurality of first content databases. And manage them in association with In stores a plurality of encryption keys in a predetermined configuration, each encryption key is characterized in that associated with the content to be managed by the plurality of first contents database by identification information.

  By defining a new standard using the content recording medium according to the present invention and applying it to a compatible device, it is possible to perform processing with a processing capability equivalent to the processing capability required for the conventional standard.

  The content recording medium of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 conceptually shows the structure of a content recording medium in Embodiment 1 of the present invention. In FIG. 1, the content recording medium 10 includes a user data area 11 and a protect area 12. The user data area 11 is an area that can be accessed by a device (not shown) connected to the content recording medium 10 regardless of whether or not the legitimacy of the device (not shown) is authenticated, and the protected area 12 is connected. This is an area that can be accessed by the device only when the mutual validity between the device and the content recording medium 10 is authenticated.

  A second content database 13 is stored in the user data area 11, and the second content database 13 includes a content database management unit 14 and a plurality of first content databases 15. The protected area 12 stores a plurality of encryption keys 16.

  FIG. 2 conceptually shows the first content database 15. The second content database 13 includes a plurality of first content databases 15, and each first content database 15 is indexed. The first content database 15 is stored under one directory, and the directory name includes a number generated from the index and starting from 001. Under the directory, SD_AUDIO. TKM and audio contents are AOB001. A plurality of items are stored in order from SA1. The plurality of first content databases have the same structure.

  FIG. 3 shows SD_AUDIO.com contained in the first content database 15. The structure of a TKM file is shown. SD_AUDIO. The TKM file stores information on each audio content, and each audio content information includes an index to the encryption key.

  FIG. 4 shows the configuration of the content database management unit 14. The content database management unit 14 includes information on all audio contents managed in all the first content databases 15, and information on one audio content includes at least a title, a database index, and a content index. A stored title table 40 is included. The database index indicates the index of the first content database 15, and the content index indicates the index of audio content stored in the first content database 15.

  Next, processing when audio content is selected and played back will be described. First, the audio content to be reproduced is selected by the content database management unit 14. Since all contents are managed by the title table in the content database management unit 14, a database index and a content index can be obtained by finding a desired title. Using the obtained database index, the first content database 15 including the desired audio content is selected from the plurality of first content databases 15, and then the desired content index is used to select the first content database 15 from the first content database 15. Audio content and SD_AUDIO. An index to the encryption key 16 is acquired from information on desired audio content managed in the TKM. Finally, an encryption key for encrypting the desired audio content is obtained from the encryption key 16 stored in the protected area 12 using the index to the encryption key 16, and the audio content is decrypted and reproduced.

  The structure of the first content database 15 is equivalent to the content database defined in the conventional standard, and the ability required for content search and playback processing is equivalent to that corresponding to the conventional standard. Appears remarkably.

  In this embodiment, it is assumed that a plurality of encryption keys 16 are stored in the protected area 12, but as shown in FIG. 5, a key database management unit 51 and a plurality of first key databases 52 are included. Two key databases 50 may be stored. In this case, SD_AUDIO. In the audio content information managed by the TKM, the index of the first key database 52 may be stored together with the encryption key index. Alternatively, if the index of the first content database 15 in which a certain audio content is included is i and the index of the audio content in the first content database 15 is j, the audio content is a first index using i as an index. The key database 52 may be encrypted with an encryption key having j as an index.

  Further, the content database management unit 14 includes information on all audio contents managed in all the first content databases 15, but at that time, the information is stored in the order sorted by the title, or sorted. Information that can extract titles in order may be stored separately, or the storage method may be determined using the hash of the title. Thereby, the search performance of the audio content when the title is known can be improved. Moreover, it is not necessary to include information regarding all audio contents, and only information regarding some audio contents may be included.

  Further, the content database management unit 14 may further improve the searchability of the user by separately storing not only the title table but also a table using attributes related to content such as artist, composer, and album.

  Further, although an example of audio content has been described in the present embodiment, the type of content is not limited. For example, digital contents that can be handled electronically, such as videos and electronic books, can be included in the subject of the present invention.

  The content recording medium according to the present invention can be applied to a copyright-protected content storage medium that can be realized within a range equivalent to the processing capability required for conventional devices even after the number of stored contents is increased.

1 is a conceptual diagram showing a configuration of a content recording medium according to Embodiment 1 of the present invention. Conceptual diagram showing an example of a first content database of the content recording medium Management file SD_AUDIO. Conceptual diagram showing a configuration example of TKM Conceptual diagram showing a configuration example of a content database management unit of the content recording medium Conceptual diagram showing another configuration example of the content recording medium

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Content recording medium 11 User data area 12 Protection area 13 2nd content database 14 Content database management part 15 1st content database 16 Encryption key

Claims (2)

A content recording medium comprising a user data area and a protect area,
The user data area is an area that can be accessed by the device regardless of whether or not the validity of the connected device is authenticated,
The protected area is an area that can be accessed by the device only when the mutual validity is authenticated between the connected device and the content recording medium.
In the user data area, a second content database including a plurality of first content databases and one content database management unit is stored,
The content database management unit manages the attribute information of the content managed in the plurality of first content databases in association with the content;
In the protected area, a plurality of encryption keys are stored in a predetermined configuration,
A content recording medium, wherein each encryption key is associated with content managed in the plurality of first content databases by identification information. The protected area stores a plurality of first key databases and a second key database including one key database management unit,
The key database management unit manages the attribute information of the encryption key managed in the plurality of first key databases in association with the encryption key;
The content recording medium according to claim 1, wherein each encryption key is associated with content managed in the plurality of first content databases by identification information.

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