JP2004023607A - Data recording medium, server, terminal, and contents utilizing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To use a plurality of encrypted contents recorded on an ID attached disk stepwise and suppress the disk production cost. <P>SOLUTION: A contents producer 10 generates data to record on a disk. The encryption for entirely encrypting the disk and the encryption for divided contents parts are adopted for encryption. A CD-R writer 15 records the encrypted contents on a CD-R, and disks on which each unique ID is recorded together with contents data are manufactured by using the CD-R as a master. A database 23 provided with a copyright source 20 stores settlement information for each disk ID, The charge for each contents part by each disk is recognized and an encryption key distributable to a user 30 can be found out by referencing the database 23. The settlement information for each ID is transmitted from the user 30 or a sales shop 40 to the copyright source 20. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a data recording medium, a server, a terminal device, and a content use system for using content such as game software and application software recorded on a read-only (ROM) type optical disk.
[0002]
[Prior art]
Music data is recorded on a CD (compact disc), and a program of application software for a computer is recorded on a CD-ROM. Conventionally, identification information unique to a recorded disk such as a CD or a CD-ROM (hereinafter abbreviated as ID as appropriate) did not exist.
[0003]
[Problems to be solved by the invention]
Therefore, it is not possible to specify or track the amount of payment and the usage status, which are information specific to the disc, and it is not possible to manage individual discs and users in pairs. Also, when a plurality of contents are recorded on a disc, the user does not always want to view all the contents, and it may be sufficient if only a part of the contents is disclosed. However, it has not been conventionally disclosed that only a part of contents is disclosed according to a user's payment situation. On the other hand, the copyright source needs to produce a plurality of types of discs in consideration of a user's use request, price burden, and the like, and there has been a problem that the production cost increases.
[0004]
Therefore, an object of the present invention is to enable a disc and a user to be managed as a pair, and to disclose a part of contents in a stepwise manner according to a user's payment status or the like. It is another object of the present invention to provide a data recording medium, a server, a terminal device, and a content utilization system capable of suppressing production costs of a disc.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is directed to a data recording medium on which encrypted content is recorded,
A plurality of content parts are encrypted with identification information unique to the data recording medium and different encryption keys, and the entirety of the plurality of encrypted content parts is further encrypted with an encryption key associated with the identification information. A data recording medium on which encrypted content data is recorded.
[0006]
According to a fourth aspect of the present invention, there is provided a copyright-source server apparatus for providing a data recording medium on which encrypted content is recorded,
In the data recording medium, a plurality of content portions are encrypted with unique identification information and different encryption keys, and the entirety of the plurality of encrypted content portions is further encrypted with an encryption key associated with the identification information. Encrypted encrypted content data is recorded,
It has a database in which payment information is recorded for each identification information,
A server that controls the provision of an encryption key for decrypting a content part with reference to a database.
[0007]
According to a seventh aspect of the present invention, in a terminal device using a data recording medium on which encrypted content is recorded,
In the data recording medium, a plurality of content portions are encrypted with unique identification information and different encryption keys, and the entirety of the plurality of encrypted content portions is further encrypted with an encryption key associated with the identification information. Encrypted encrypted content data is recorded,
Along with the identification information, the settlement information corresponding to the use request of the content portion is transmitted to the server,
The terminal device receives an encryption key for decrypting a content portion according to payment information from a server.
[0008]
According to a tenth aspect of the present invention, there is provided a content utilization system utilizing an encrypted content recorded on a data recording medium,
In the data recording medium, a plurality of content portions are encrypted with unique identification information and different encryption keys, and the entirety of the plurality of encrypted content portions is further encrypted with an encryption key associated with the identification information. Encrypted encrypted content data is recorded,
The copyright server that provides the data recording medium
It has a database in which payment information is recorded for each identification information,
Control the provision of an encryption key for decrypting the content part by referring to the database,
A terminal device that uses a data recording medium
Along with the identification information, the settlement information corresponding to the use request of the content portion is transmitted to the server,
The content utilization system is configured to receive an encryption key for decrypting a content portion according to payment information from a server.
[0009]
According to the present invention, the copyright source can manage the payment information for each disc by the identification information, and the stepwise use of a plurality of content portions can be enabled according to the payment information. The user can reduce the burden of the fee by paying for the content portion desired to be used. On the other hand, the copyright source only needs to produce one kind of disc, and the production cost can be reduced. Furthermore, since the entire content portion of the disc is encrypted with the encryption key associated with the identification information, protection against illegal copying can be achieved.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described. In one embodiment, unique identification information (hereinafter, appropriately referred to as ID) is recorded on an optical disc, such as a CD-ROM, on which application software, movie software, music software, and the like are recorded. The ID is information for identifying each disk. Since it is only necessary to be able to identify individual disks, symbols, characters, etc. other than numbers may be used. The ID uniquely identifies a predetermined number of CD-ROMs on which application software is recorded. The ID is recorded so that it can be read by, for example, an existing CD player or CD-ROM drive. First, the structure of an optical disk, for example, a CD will be described to facilitate understanding of one embodiment.
[0011]
FIG. 1 shows an enlarged part of an existing CD-ROM. On a track having a predetermined track pitch Tp (for example, 1.6 μm), concave portions called pits and lands on which no pits are formed are alternately formed. The lengths of the pits and lands are in the range of 3T to 11T. T is the shortest inversion interval. The CD-ROM is irradiated with laser light from below.
[0012]
A structure in which a transparent disk substrate 1 having a thickness of 1.2 mm, a reflective film 2 coated thereon, and a protective film 3 coated on the reflective film 2 are sequentially stacked from the lower side irradiated with the laser light. Have been. The reflection film 2 having a high reflectance is used. The CD-ROM is a read-only disc. As described later, after the reflective film 2 is covered, information (ID) is recorded on the reflective film 2 by using a high-output laser beam.
[0013]
The flow of the manufacturing process of such a CD-ROM will be described with reference to FIG. In step S1, a glass master on which a photoresist, which is a photosensitive substance, is applied to a glass plate is rotated by a spindle motor, and a laser beam that is turned on / off in response to a recording signal is applied to the photoresist film to create a master. You. The photoresist film is developed, and in the case of a positive resist, the exposed portions are melted, and a concavo-convex pattern is formed on the photoresist film.
[0014]
One metal master is created by an electroforming process of plating a photoresist master (step S2). A plurality of mothers are created from the metal master (step S3), and a plurality of stampers are created from the mother (step S4). A disk substrate is created using the stamper. As a method for producing a disk substrate, compression molding, injection molding, light curing method, and the like are known. Then, in step S6, a reflective film and a protective film are deposited. In the conventional disk manufacturing method, a CD-ROM is further manufactured by performing label printing.
[0015]
On the other hand, in the example of FIG. 2, a step S7 of irradiating a high-power laser beam to the reflection film (mirror portion, for example, land) and additionally recording information is added. In the land on the reflective film, atoms move due to heat treatment (thermal recording) in which laser light is irradiated, and the film structure and crystallinity change, and the reflectance at that location decreases. As a result, even if the land is used, after the laser beam is irradiated, the amount of the returned laser beam is reduced, and the land is recognized by the reading device in the same manner as the pit. Using this, the pit length or land length can be changed to record information. In this case, a material whose reflectivity changes by laser irradiation is used for the reflective film. Not only materials whose reflectivity is reduced but also materials whose reflectivity is increased by recording are available.
[0016]
Specifically, the reflection film is composed of an alloy film _{Al 100-x X} x of aluminum. As X, at least one element of Ge, Ti, Ni, Si, Tb, Fe, and Ag is used. The composition ratio x in the Al alloy film is selected to be 5 <x <50 [atomic%].
[0017]
It is also possible to configure the reflective film by the Ag alloy film of _{Ag 100-x X} x. In this case, at least one of Ge, Ti, Ni, Si, Tb, Fe, and Al is used as X. The composition ratio x in the Al alloy film is selected to be 5 <x <50 [atomic%]. The reflection film can be formed by, for example, a magnetron sputtering method.
[0018]
As an example, when a reflective film made of an AlGe alloy is formed with a thickness of 50 nm and a laser beam is irradiated from the transparent substrate or the protective film side via an objective lens, when the Ge composition ratio is 20 [atomic%], When the recording power is 6 to 7 mW, the reflectivity decreases by about 6%, and when the Ge composition ratio is 27.6 at%, the recording power is 5 to 8 mW. Then, the reflectivity decreases by about 7 to 8%. Such a change in reflectance enables additional recording on the reflective film.
[0019]
FIG. 3 is a diagram for more specifically explaining a method of additionally recording an ID. The correspondence between the recording data and the pits and lands can be a pattern A or a pattern B in relation to the previous pattern.
[0020]
First, the pattern A will be described. For example, three merge bits (000) are inserted between the symbols. When additional recording is performed, an 8-bit data symbol is set to, for example, (0x47). 0x means hexadecimal notation. FIG. 3 shows a 14-bit pattern (00100100100100) resulting from EFM (Eight to Fourteen Modulation) modulation of these 8 bits.
[0021]
Then, a laser beam for additional recording is irradiated to a hatched area between the two pits. As a result, the reflectivity of the shaded area decreases, and after recording, the data is reproduced as one pit in which two pits are combined. In this case, the 14-bit pattern is (0010010000000). This is demodulated as (0x07) 8 bits when EFM demodulation is performed.
[0022]
In the case of pattern B, the merge bit is (001). Also in this case, similarly to the pattern A, by irradiating the hatched area with the laser beam, the 8 bits can be changed from (0x47) to (0x07).
[0023]
As described above, a data symbol that was originally (0x47) can be rewritten to (0x07). In addition to this example, there are many types of data that can be additionally recorded. For example, a data symbol that was originally (0x40) can be changed to (0x00). However, additional recording involves changing the pit length or land length by irradiating a laser to the mirror portion of the originally recorded data, so that the type of data that can be additionally recorded is limited.
[0024]
FIG. 3 shows an example of additional recording. As a method of recording an ID, a method of intentionally generating an EFM error in a predetermined section and additionally recording an ID according to the presence or absence of the EFM error, and a method of using an error correction code Various methods such as a method of intentionally adding an uncorrectable error are possible. Since the ID recorded on the disk is not formed as a pit on the disk substrate, the ID is not copied to a disk illegally created using the disk substrate as a master. In addition, the content of the ID cannot be easily determined by encoding at the time of additional recording. Therefore, usually, it is possible to prevent the ID from being read illegally. Even if the ID is read illegally, the information is information of the disk alone and is not valid as the ID of another disk. Therefore, there is an advantage that damage caused by reading the ID is small.
[0025]
The present invention proposes a business model using a disc such as a CD-ROM on which a disc identification ID is recorded, as described above. Hereinafter, an example of a business model according to the present invention will be described. In the following description, the above-mentioned disk will be referred to as an ID-attached disk as appropriate.
[0026]
FIG. 4 shows a system configuration for realizing the business model. Reference numeral 10 denotes a content creator, and reference numeral 11 denotes a content creator's personal computer (hereinafter abbreviated to PC as appropriate). The PC 11 is a general-purpose PC in which an application for producing a CD-ROM is installed. The Internet interface 12 is an interface with the Internet. As the Internet interface 12, 10BASE-T, 100BASE-T, ADSL (Asymmetric Digital Subscriber Line), PPP (Point-to-Point Protocol), or the like can be used.
[0027]
In the PC 11 of the content creator 10, encryption software 13 for encrypting the entire disc and software 14 for encrypting the divided portions are installed. Here, the entire encryption is to encrypt data using the disk ID itself or data related to the ID as an encryption key group. The encryption key of the divided portion means that a plurality of content portions (hereinafter, appropriately referred to as chapters) are encrypted with different encryption keys. The completed encrypted content is recorded on the CD-R by the CD-R writer 15.
[0028]
In a disc manufacturing factory (not shown) using the CD-R as a master, a disc with an ID is manufactured through the steps described with reference to FIG. A copyright source 20, which will be described later, instructs the content creator 10 and the disc manufacturing factory, and a desired number of discs on which desired content is recorded is manufactured. The disc on which the encrypted content is recorded is additionally recorded with an ID for identifying each disc. The disc manufacturing factory has information on what kind of ID is recorded. The information of the pair of the ID and the encrypted content is transmitted to the copyright source 20 via the Internet.
[0029]
Reference numeral 20 denotes a copyright source, and reference numeral 21 denotes a PC of the copyright source 20. The PC 21 controls mutual data communication between the Internet interface 22 and the two types of databases 23 and 24. The Internet interface 22 indicates an interface with the Internet. As the Internet interface 22, 10BASE-T, 100BASE-T, ADSL, PPP, or the like can be used.
[0030]
The database 23 included in the copyright source 20 stores settlement information for each disk ID sent from a later-described store 40 via the Internet, for example. It is also possible for the settlement information to be transmitted from the user 30 described later to the copyright source 20 via the Internet. By referring to the database 23, after confirming the content of the transmitted ID, it is possible to first determine at which charging level the disk of the ID was distributed. For example, payment information such as whether a fee for viewing all contents recorded on the disk has been paid or a fee for viewing only some contents has been paid is stored on the disk 23. .
[0031]
The other database 24 stores information on the encryption key pair content received from the content creator 10. That is, encryption key information for encryption of the divided portions is stored in the database 24, and a key to be distributed to the user is selected based on the result determined in the database 24.
[0032]
Reference numeral 30 indicates a user, and reference numeral 31 indicates a terminal device of the user, for example, a PC. The PC 31 is a general-purpose PC generally used in homes and offices. Application software for using the disc with ID is installed in the PC 31 in advance. Reference numeral 32 indicates a CD-ROM drive built in the PC 31. Reference numeral 33 indicates an interface with the Internet. As the Internet interface 33, 10BASE-T, 100BASE-T, ADSL, PPP, or the like can be used. The user 30 can transmit the settlement information to the copyright source 20 via the Internet interface 33.
[0033]
Reference numeral 40 indicates a store, and reference numeral 41 indicates a terminal of the store 40. The terminal 41 is a terminal that can perform payment processing. For example, the terminal 41 includes a barcode reader 42 for billing processing. The bar code reader 42 reads the bar code 43 indicating the product classification and the contents of the ID written on the disc, and sends the information to the server on which the database 23 of the copyright source 20 is constructed. Information such as a product classification (for example, a title number) and contents of an ID (for example, a serial number) is sent to the server of the copyright source 20. At the same time, as described above, the ID of the distributed disk and the information on the settlement conditions of the disk are sent to the server of the copyright source 20, and the database 23 is constructed. Discs can be distributed free of charge, not just paid. In addition, the information on the settlement conditions includes information on the price paid for the disc in accordance with the range of contents to be viewed.
[0034]
Reference numeral 50 denotes a disk with an ID. The content produced by the copyright source 20 is recorded on the disk 50 with ID. The content recorded on the disk 50 is encrypted for each part with an encryption key, and the entire content data is encrypted with an encryption key group.
[0035]
FIG. 5 shows an outline of a process of encrypting content recorded on a disc. In FIG. 5, the content data DT1 at the top indicates content data to be recorded on one disc. The content data DT1 is composed of chapter 1 (Ch-1) to chapter 7 (Ch-7). As an example, chapters are used step by step according to their number order.
[0036]
Each chapter is encrypted with a different encryption key (Key-A, Key-B, Key-C, Key-D, Key-E, Key-F, Key-G). The encryption key is selected from an encryption key group KL1 preset by the content creator. In FIG. 5, AL1 represents an algorithm for performing encryption (section encryption) for each chapter. For example, the content data of the chapter Ch-1 is encrypted with the encryption key Key-A. In FIG. 5, DT2 indicates segmented encrypted data in which the data of each chapter is encrypted with a different encryption key. As the encryption algorithm, DES (Data Encryption Standard) or the like can be used.
[0037]
Then, the data DT2 including the divided and encrypted chapters 1 (Ch-1 *) to 7 (Ch-7 *) is entirely encrypted. In this case, an encryption key Key-Main # 1 from the encryption key group KL2 and an encryption algorithm indicated by AL2 are used. The encryption key used for the whole encryption is the ID itself or the one associated with the ID. If the ID is different, the encryption key of the whole encryption is also different. DES or the like can be used as the encryption algorithm. As described above, the ID is less likely to be copied illegally, and it is also difficult to read the ID. Therefore, it is difficult to illegally obtain the entire encryption key, and copy protection can be achieved by the entire encryption.
[0038]
Data DT3 double-encrypted by both the encryption algorithms AL1 and AL2 is recorded on the disk. For example, when one session is formed by the lead-in area, the program area, and the lead-out area, the content data DT3 is recorded in the program area.
[0039]
An example of the business model provided by the present invention in the system configuration shown in FIG. 4 will be described. The user 30 obtains the ID-added disk distributed by the copyright source 20. For example, computer programs, game software, music software, movie software, and the like are recorded on the disc. As described with reference to FIG. 5, the content recorded on the ID-added disk is divided into chapters and encrypted by encryption, and the entire content data is entirely encrypted. Things.
[0040]
The user 30 can obtain the disc in two ways. The first method is a method of obtaining a disc with an ID for zero price, and then performing a settlement process for part or all of the content to the copyright source 20 via a network. As a result, when the content is a program, the user 30 acquires the right to use the program, and when the content is music, movie, or the like, the user 30 acquires the viewing right to view the music, movie, or the like. . In the following description, the right of the user 30 to use the program and the right of the user 30 to view the content are collectively referred to as a content usage right.
[0041]
On the other hand, the copyright source 20 obtains information on the contents of the ID and the price paid by the user from the user 30 through the settlement process. The contents of the ID include an ID number, title information of the content recorded as the ID, information on the date of manufacture of the disc, and the like. Note that a trial version and samples that are not encrypted and can be used free of charge are recorded on the disc.
[0042]
The second method is that the user 30 pays for some or all of the content and obtains a disc with an ID on an existing available goods purchase route. A path in which the user 30 obtains the ID-added disk from the store 40 in the system of FIG. 4 is an example of the article purchase path. At this time, the store 40 reports the contents of the ID and the value of the ID to the copyright source 20 via, for example, the Internet.
[0043]
The copyright source 20 constructs a database 23 in which the contents of the ID received in the first method or the second method described above and the information on the price paid by the user 30 are recorded in pairs. The copyright source 20 determines the range of the key to be passed to the user with reference to the database 23.
[0044]
The user 30 inserts the obtained disk with ID into the CD-ROM drive 32 of the PC 31. With the software installed in the PC 31, the PC 31 first reads the ID from the disk. If the ID is correctly read, an encryption key for the whole encryption can be obtained, and the whole encryption can be decrypted. If the user 30 likes the trial version, the sample chapters, or the paid chapters, and wants to use the related chapters further, the additional payment processing is performed on the copyright source 20 via the network, Purchase content usage rights.
[0045]
The copyright source 20 updates the settlement information of the additionally paid ID in the database 23. Then, a key for enabling the use of a chapter corresponding to the additionally paid consideration is transmitted to the user 30 via the network. The user 30 receiving the key can use the new chapter.
[0046]
In the example of the business model described above, at the time when the user 30 obtains the disc with the ID, there is no need to pay for the content for which it is not possible to immediately determine whether it is necessary or not, and it is possible to prevent the user 30 from paying for unnecessary use. On the other hand, the copyright source 20 only needs to pass the encryption key for each chapter of the content recorded on the disc in part or stepwise according to the price paid by the user 30. Production is sufficient, and production costs can be reduced.
[0047]
Next, another example of the business model according to the present invention will be described. Another example is suitable when the content recorded on the disc with ID is a learning program or a training program. The user (learner in this example) 30 pays for an article purchase route existing in the world, for example, a store 40, and purchases the ID-added disk 50 released from the copyright source 20. The ID-added disk 50 stores a learning or training program. The whole encryption of the ID-added disk 50 that is properly obtained can be decrypted in the PC 31 of the user 30.
[0048]
The store 40 reports the content of the sold ID and the price paid by the user 30 to the copyright source 20 via, for example, the Internet. The copyright source 20 constructs a database 23 in which ID information from the store 40 and the price are paired, and when the user 30 requests the use of the additional content portion, a key for decrypting the additional information is obtained. Get ready to hand it.
[0049]
A user 30 as a learner sees and learns the basic content, and performs a test via the network for receiving an evaluation of the progress of the learning. The management of the test is performed by the copyright source 20, for example. If it is determined from the test results that supplementary learning is necessary, settlement is made to the copyright source 20 via the Internet, and an encryption key that enables browsing of chapters of the supplementary learning material is purchased from the copyright source 20. For example, the user 30 transmits settlement information (for example, a settlement method, a credit card number, etc.) to the copyright source 20 together with the ID read from the disk 50. The copyright source 20 updates the settlement information of the additionally paid ID in the database 23. Then, a key for enabling the use of the chapter of the supplementary teaching material for the additionally paid price is transmitted to the user 30 via the network so that the user 30 can view the key.
[0050]
If the ability of the user 30 is high and the test result is good, there is no need to pay for the supplementary teaching material because the supplementary teaching material is unnecessary. On the other hand, the copyright source 20 only has to pass the encryption key for disclosing the teaching material on the disk 50 in a stepwise manner according to the ability, request, etc. of the user 30, so that only one type of disk needs to be produced. Production costs can be reduced.
[0051]
The present invention is not limited to the embodiment of the present invention described above, and various modifications and applications are possible without departing from the gist of the present invention. For example, as a method of paying the user's consideration, if the user desires, it may be possible to pay the consideration for making all the contents on the disc usable. In addition, the present invention is not limited to the additional recording on the reflection film, and can record the ID by additionally recording on the phase change film, the magneto-optical recording film, or the like. Further, the present invention can be applied to, for example, a DVD video and a DVD-ROM. Further, the present invention is not limited to an optical disk medium, and can be applied to a data recording medium such as a semiconductor memory and a memory card.
[0052]
【The invention's effect】
As is apparent from the above description, according to the present invention, a unique ID is recorded on a data recording medium such as a disc, and the content is divided and encrypted, so that the settlement is made in units of ID and for each part of the content. Information can be managed. This prevents the user from paying for unnecessary content. On the other hand, the content creator only has to produce a data recording medium on which one kind of content composed of a plurality of parts is recorded, and the production cost can be suppressed as compared with the multi-product small-quantity production. Furthermore, since the entire content is encrypted by the ID itself or the encryption key associated with the ID, the copyright of the content can be protected.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating a recording pattern of a conventional CD and a structure of the CD.
FIG. 2 is a schematic diagram illustrating a manufacturing process of a disk according to an embodiment of the present invention.
FIG. 3 is a schematic diagram used for describing additional recording according to an embodiment of the present invention.
FIG. 4 is a schematic diagram illustrating a configuration of a content use system according to an embodiment of the present invention.
FIG. 5 is a schematic diagram used for describing encryption processing according to an embodiment of the present invention.
[Explanation of symbols]
10: content creator, 20: copyright holder, 30: user, 40: dealer, 50: disc with ID

Claims (10)

In a data recording medium on which encrypted content is recorded,
A plurality of content portions are encrypted with identification information unique to the data recording medium and different encryption keys, and the entirety of the plurality of encrypted content portions is further encrypted with an encryption key associated with the identification information. A data recording medium on which encrypted content data is recorded. In claim 1,
A data recording medium, wherein the plurality of content portions are used step by step. In claim 1,
Further, a data recording medium on which an unencrypted content portion is recorded. In a server apparatus of a copyright source that provides a data recording medium on which encrypted content is recorded,
In the data recording medium, a plurality of content parts are encrypted by unique identification information and mutually different encryption keys, and the whole of the plurality of encrypted content parts is further encrypted by an encryption key associated with the identification information. Encrypted encrypted content data is recorded,
A database in which payment information is recorded for each of the identification information;
A server that controls provision of an encryption key for decrypting the content part with reference to the database; In claim 4,
A server in which the plurality of content parts are used in stages. In claim 4,
A server in which an unencrypted content portion is further recorded on the data recording medium. In a terminal device using a data recording medium on which the encrypted content is recorded,
In the data recording medium, a plurality of content parts are encrypted by unique identification information and different encryption keys, and the entirety of the encrypted plurality of content parts is further encrypted by an encryption key associated with the identification information. Encrypted encrypted content data is recorded,
Along with the identification information, the settlement information corresponding to the use request of the content portion is transmitted to the server,
A terminal device for receiving an encryption key for decrypting a content portion according to the payment information from a server. In claim 7,
A terminal device in which the plurality of content portions are used in stages. In claim 7,
A terminal device in which an unencrypted content portion is further recorded on the data recording medium. In a content use system that uses encrypted content recorded on a data recording medium,
In the data recording medium, a plurality of content parts are encrypted by unique identification information and different encryption keys, and the entirety of the encrypted plurality of content parts is further encrypted by an encryption key associated with the identification information. Encrypted encrypted content data is recorded,
The server of the copyright source that provides the data recording medium,
A database in which payment information is recorded for each of the identification information;
Controlling provision of an encryption key for decrypting the content portion with reference to the database,
A terminal device using the data recording medium,
Along with the identification information, transmitting payment information corresponding to the use request for the content portion to the server,
A content utilization system configured to receive an encryption key for decrypting a content portion according to the payment information from the server.

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