JP2003337803A - Contents illegal acquisition preventing method, system and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contents illegal acquisition preventing method, system and program for invalidating illegal access associated with contents. <P>SOLUTION: A contents distribution request transmitted from a user terminal 4 is received by a contents distribution system 2 (a step S1). Then, a contents distribution system 2 divides a contents file supplied from a contents provider, and adds a noise to each divided file, and enciphers it to prepare a plurality of divided files, and distributes the distributed files to a user terminal 4 (a step S2). When all divided files (for one contents) are received, the user terminal 4 decodes those respective divided files, and connects the decoded files to restore the contents file (a step S3). <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a content distribution system for distributing content via a communication line by a communication network such as the Internet, and particularly suitable for making meaningless unauthorized access related to the content. The present invention relates to an illegal acquisition prevention method, a content illegal acquisition prevention system, and a content illegal acquisition prevention program.

[0002]

2. Description of the Related Art In recent years, with the development of high-speed communication technology and high compression technology of video data on the Internet, contents such as video, music and computer game software have come to be distributed through a communication line.

FIG. 10 is a block diagram showing a schematic configuration of a conventional content distribution system. In FIG. 10, the content providing server 201 is a content providing source and has content data. The content providing server 201 supplies a file of content data (hereinafter referred to as a content file) to each distribution server 202 via the Internet 3. Each distribution server 202 is installed on the communication network within the Internet 3, stores the content file received from the content providing server 201, and downloads the content file in response to a request from the user terminal 4.

In the content distribution system of FIG. 10, the content providing server 20 is provided in order to prevent congestion of the communication line due to concentration of download of content files.
A plurality of distribution servers 202 are installed on the communication network as mirror servers (cache servers) that store the same content data as 1. Then, conventionally, from the distribution server 202 located in the communication network near the user terminal 4 that has requested the content,
The content file is being downloaded.

[0005]

However, in the prior art, since there is a comparatively easy illegal access to the cache server, there is a problem that an unauthorized person may illegally obtain the content. . This problem will be described below.

[0006] Conventionally, a method of distributing content data by encrypting it has been devised in order to prevent illegal acquisition of content. The encryption methods are 1) a code conversion method for converting the code value for each unit data (one character, etc.), 2) a position replacement method for changing the position of the unit data, and 3) a code. There is a method that combines the conversion method and the position replacement method.

However, if the encryption strength is increased in the conventional encryption method, a large amount of calculation processing is required for the encryption processing, and the load on the content providing server, the distribution server and the network becomes excessive, and the data capacity is increased. As the number of users increases, it becomes difficult to smoothly distribute video data such as moving images. Also, a large amount of calculation processing is required for the decoding processing in the user terminal, which makes it difficult to smoothly view video data such as a moving image.

The present invention has been made in view of the above-mentioned circumstances, and is a method for preventing illegal content acquisition, a system for preventing illegal content acquisition, and a program for preventing illegal content acquisition, which makes meaningless unauthorized access to content. For the purpose of provision.

[0009]

In order to achieve the above object, according to the invention of claim 1, there is provided a method for preventing illegal acquisition of contents, which is used in a system for distributing contents, wherein at least one of the contents is The image content that constitutes one is image data, and the image content is divided into a plurality of files, and noise is added to each of the divided files for encryption. According to such a method, since noise is added to each divided file for encryption, the noise cannot be decrypted unless the noise of each divided file is taken.
Not only this, but because the image data is divided into multiple files, even if an unauthorized person tries to decipher the divided files by estimating noise, the original data is image data. You will not know what was correctly decoded. Therefore, according to such a method, if the order of the divided individual files is not known, even if the divided and encrypted files are simply illegally acquired, it is impossible to restore the original contents, and the illegal contents are illegal. It is possible to make access meaningless.

The invention according to claim 2 is characterized in that the divided and encrypted files are stored in an irregular order in a database.

According to the third aspect of the invention, the management server for controlling the distribution of the contents is divided into two layers, a database control server and a file management server,
The database control server manages the name of the content in association with the system name that is the name of the content in the system, and the file management server manages the system name and the divided and encrypted file. It is characterized by managing the storage location and. According to such a method, the management server is divided into two layers of the database control server and the file management server, and the data regarding the name of the content and the storage location of the content are managed by different servers. Even if the data related to the storage location of the content is illegally acquired and the data that is a part of the content is illegally acquired, it is not possible to know what kind of content the data is,
It is possible to make unauthorized access meaningless.

Further, in the invention according to claim 4, the database control server performs a predetermined process on the name of the content related to the content distribution request from the user, converts it into the in-system name, and sends it to the file management server. The file management server performs control for delivering the divided and encrypted files of the content related to the in-system name to the user, and provides information indicating that all the divided files have been received from the user. When received by the database control server, the database control server controls to cause the user to transmit noise removal data for removing the noise.

Further, in the invention according to claim 5, after the user removes noise from the divided and encrypted files by using the noise removal data, a combining code for combining the divided files is provided. The information requesting transmission is transmitted to the database control server.

Further, in the invention according to claim 6, the distribution server having the divided and encrypted file communicates with the terminal of the user and distributes the file to the terminal of the user. .

In order to achieve the above-mentioned object, in the invention described in claim 7, the content data is distributed from the distribution server to the user related to the regular access, and the content data acquired by other than the regular access is invalidated. And a content division file generation unit that divides an image content composed of image data into a plurality of files and adds noise to each divided file for encryption. And

Further, in the invention according to claim 8, the distribution server stores the divided and encrypted files in irregularly allocated locations, and controls the distribution server. A database control server that manages a content name and an in-system name that is a name of the content in the system in association with each other, and controls the distribution server, wherein the in-system name and the divided and encrypted And a file management server that manages the storage location of the file.

In order to achieve the above-mentioned object, the invention according to claim 9 is a content illegal acquisition preventing program used in a system for distributing contents, which constitutes at least one of the contents. It is characterized in that the computer is made to perform a step of dividing the image content composed of image data into a plurality of files and a step of adding noise to each of the divided files and encrypting the divided files.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In the following description, as the content to be distributed, for example, image data (video data) showing a moving image or a still image is preferable.

FIG. 1 is a block diagram showing a configuration example of a content illegal acquisition preventing system using a content distribution system 2 according to an embodiment of the present invention. In FIG. 1, a content provider 1 is a source of content such as computer game software, and supplies a content file (CF) to a content distribution system 2. The content delivery system 2 is connected to the Internet 3 and delivers content via a communication line. The user uses the user terminal 4 to access the Internet 3
To access the content distribution system 2 to request content.

First, the outline of the operation of the illegal content acquisition prevention system using the content distribution system 2 will be described with reference to FIG. FIG. 2 is a sequence diagram for explaining the outline operation of the illegal content acquisition prevention system shown in FIG. First, the content distribution system 2 receives the content distribution request transmitted from the user terminal 4 (step S1). Then, the content distribution system 2 divides the content file (CF) supplied from the content provider 1, adds noise to each of the divided files, and encrypts the divided files to create a plurality of divided files. The file is distributed to the user terminal 4 (step S2). Upon receiving all the divided files (for one content), the user terminal 4 decrypts each divided file, combines the decrypted files, and restores the content file (CF) (step S3).

As a result, even if a person who tries to acquire the content file (CF) illegally can acquire the divided file, it cannot be decoded unless noise is taken from the divided file. Not only this, according to the above method, the image data is divided into multiple files, so
Even if an unauthorized person tries to decipher the divided file by estimating noise, it cannot be known that the deciphered file was correctly deciphered because the original data is image data.
On the other hand, for example, if the content file (CF) is text data and is composed of a text file, each divided file has a meaning, and it is easy to determine whether or not it has been correctly decoded. Therefore, according to the above method, if the individual order of the divided files is not known, even if the divided files are simply illegally acquired, it will not be possible to restore the original contents, making illegal access meaningless. Becomes

Next, the structure of the content distribution system 2 will be described with reference to FIG. FIG. 3 is a block diagram showing the configuration of the content distribution system 2 shown in FIG. In FIG. 3, the content distribution system 2 includes a content division file (CFC) generation unit 100, a pull type distribution control unit 110, a push type distribution control unit 120, and a plurality of distribution server (DS) groups 130. The pull-type delivery control unit 110, the push-type delivery control unit 120, and each delivery server (DS) group 130 are connected to the Internet 3 and are accessible from the user terminal 4.

The content division file generation unit 100
The content file (CF) supplied from the content provider 1 is divided into a plurality of content division files (C
FC). This one content division file corresponds to one download file, and one content is composed of all the content division files.
The content division files are supplied to the pull-type delivery control unit 110 and the push-type delivery control unit 120, respectively.

Next, the content division file generation unit 10
The operation of 0 will be described with reference to FIG. FIG. 4 is a flowchart showing the operation of the content division file generation unit 100. First, when the content distribution system 2 receives a content file (CF) from the content provider 1, the content division file generation unit 100 scrambles the original file (File A) which is the content file (CF) itself to scramble the file. (File A ') is generated (step S11).

Here, the content file (CF) is
It is preferably an image file including data indicating a moving image or a still image. This is because, as described above, the present invention is particularly effective as a countermeasure for illegal acquisition of image files.

Next, the content division file generation unit 1
00 encrypts the scramble file (File A ') to generate an encrypted file (File A ") (step S).
12). Next, the content division file generation unit 100
Compresses the encrypted file (File A ") to generate a compressed file (File A"') (step S13). Next, the content division file generation unit 100 divides the compressed file (File A ″ ′) to generate a plurality of content division files (CFC) (step S14).

A content division file (CFC)
The size of is preferably a fixed value of, for example, about 3 megabytes. This is to make the residence time for the user to access the content distribution system 2 substantially equal. Further, in order to cope with the case where the user terminal 4 is connected to a low speed line, the control server (distribution server 131) accessible from the user terminal 4 is divided, and a small capacity content division file (CFC) is prepared. It is preferable to set.

Further, the content division file generation unit 1
00 confirms whether the generated content division file (CFC) is valid, in other words, whether the content division file (CFC) can be returned to the content file (CF) by a valid user. . Specifically, first, the content division file generation unit 100
Executes the process of returning the generated content division file (CFC) to the original content file (CF). Next, the content division file generation unit 100 compares the returned file with the content file (CF) supplied from the content provider 1. This comparison is performed bit by bit. As a result of the comparison, if there is no difference, that is, if the file decoded by the above procedure and the content file (CF) are exactly the same, it can be confirmed that the content division file (CFC) is appropriate. It will be. On the other hand, as a result of the comparison, if there is a difference, the content division file (CFC) is not valid and the content division file generation unit 100 regenerates the content division file (CFC).

The content division file (CFC) generated by the content division file generation unit 100 is supplied to the pull type delivery control unit 110 and the push type delivery control unit 120, respectively, as shown in FIG. Next, the pull-type delivery control unit 110 and the push-type delivery control unit 120 will be described with reference to FIG.

The pull-type delivery control unit 110 includes the user terminal 4
Control is performed to deliver the content by sequentially downloading the file in response to the content request from the user. The pull-type delivery control unit 110 includes a control unit 111 and a plurality of file management units 112.

The control unit 111 mainly manages access from the user terminal 4, selection of the file management unit 112 according to download, and management of download file allocation amount according to access amount from the user terminal 4 to the file management unit 112. , And creates a download file (CFA). One download file (CFA)
Is created based on one content division file.
The download file is supplied to the file management unit 112.

The file management unit 112 manages one distribution server group 130, and mainly manages storage of download files in each distribution server 131, operation status management of each distribution server 131, and the like. .

The push-type delivery control unit 120 performs control for delivering content by performing file download in advance in response to a content request from the user terminal 4. The push-type delivery control unit 120 includes a control unit 121 and a plurality of file management units 122.

The control unit 121 mainly manages access from the user terminal 4, selection of the file management unit 122 according to download, management of download file allocation amount according to access amount from the user terminal 4 to the file management unit 122. , Create download files, etc. One download file (CFA) is created based on one content division file. The download file is supplied to the file management unit 122.

The file management unit 122 manages one distribution server group 130, and mainly manages storage of download files in each distribution server 131, operation status management of each distribution server 131, and the like. .

The distribution server group 130 is composed of a plurality of distribution servers 131. The distribution server 131 stores the download file and transmits the download file to the user terminal 4.

Next, the process of creating the download file (CFA) will be described with reference to FIG. FIG. 5 is a table showing the ID of the redundant code and the data information of the redundant code included in the download file (CFA). That is, the control unit 111 creates a download file (CFA) by adding a redundant code to each content division file (CFC). Here, the redundant code is data that becomes noise for the content division file (CFC). Therefore, the content division file (CFC) is encrypted by adding the redundant code that becomes noise.

Specific download file (CFA)
The creation processing of will be described. The control unit 111 holds the redundant code ID and the redundant code data information shown in FIG. In this figure, "Time Stam
“P” is data indicating the date and time when the redundant code table was created. "Code ID" is hexadecimal notation data, and is about 4 to 8 bytes. "Code
"Length" is data indicating the length of the redundant code, and the length has a fixed length and a variable length. For example, it is assumed that the length of the redundant code is in the range of 24 to 120 bytes and can be changed for each byte.

"Code Data" is data forming a redundant code, and is generated, for example, by randomly generating a simple hexadecimal value. "Code
Position "is a content division file (CF
This is data indicating the insertion position of the redundant code in C), and for example, the insertion position is at the end of the content division file or an arbitrary position. "Code Pattern"
Is data indicating how the redundant code embedded in the content division file (CFC) is added. As for "Code Pattern",
For example, each method such as 1) simply adding a code, 2) embedding by a logical operation (AND or XOR), and 3) bit reversal of a redundancy target portion can be applied.

As a result, the control unit 111 uses the table shown in FIG. 5 to divide each content division file (CF
A download file (CFA) is created by adding a redundant code for each C). The push-type delivery control unit 120 also creates a download file (CFA) in the same manner as the download file (CFA) creation process in the pull-type delivery control unit 110.

The control unit 111 supplies each created download file (CFA) to the file management unit 112. The file management unit 112 stores the supplied download file (CFA) in the distribution server 131.
Here, the control unit 111 controls the file management unit 112 to disperse and store each download file (CFA) in a plurality of distribution servers 131 in an irregular order.

Therefore, the control unit 111 functions as a database control server, as shown in FIG. Then, the control unit 111 manages the source file (content file (CF)) unit related to the user's request,
The file management unit 112 also manages the distribution file (download file (CFA)) unit. On the other hand, the file management unit 112 functions as a file management server, and allocates a distribution file (download file (CFA)) to each distribution server 131 and controls distribution.

Specifically, the control unit 111 controls the content division file (FileC-CFC) for each content division file (CFC) for each name (for example, FileA-CFC1) in the system.
It has a mapping table that associates the name (for example, FileA-CFA1) of the download file (CFA) of A-CFC1) in the system. Here, the name of the content division file (CFC) in the system (FileA-CFC
Only the control unit 111 grasps and manages the relationship between 1) and the name of the content file (CF) that is the original file of the content division file (CFC).
On the other hand, the file management unit 112 determines the relationship between the name (FileA-CFA1) of the download file (CFA) in the system and the storage location of the download file (CFA) (name and storage address of the distribution server 131). Understand and manage.

By these, the content file (C
F) is divided and encrypted to create a download file (CFA), and the storage location of the download file (CFA) and the like are managed by a two-level server of the control unit 111 and the file management unit 112. Even if the server 131 is illegally accessed and a part of the download file (CFA) is illegally acquired, it is very difficult to decipher the download file (CFA) and it is determined what the content indicates. It becomes impossible to do. That is, the content file (CF) is an image file, one download file (CFA) is a part of the image,
Since encryption is performed by adding noise, it is virtually impossible to judge whether or not the download file (CFA) could be decrypted even if the decryption is tried. Even if all the download files (CFAs) are illegally acquired, they are randomly stored in the plurality of distribution servers 131. Therefore, the download files (CFAs) should be listed in the correct order. Is virtually impossible, and the illegally acquired download file (CFA) is rendered meaningless.

Next, the flow of content distribution processing by the pull type distribution control unit 110 will be described with reference to FIG. FIG. 7 is a sequence diagram for explaining content distribution processing in the content distribution system 2 and content reproduction processing in the user terminal 4. In the following description, the content file (CF) is divided into a plurality of content division files (CFC1 to m, m is an integer of 2 or more), and these content division files (CFC1 to CFC1 to m) are divided.
m) is encrypted by adding a redundant code (noise) to each of the downloaded files (CFA1 to CFA1).
m), and the download file (CFA1-
m) is to be delivered to the user terminal 4. And
The user can download these download files (CFA1-
Content can be acquired from m).

First, the pull-type delivery control unit 110 receives a content acquisition request from the user terminal 4 (step S).
21). Then, the control unit 11 of the pull-type delivery control unit 110
1 changes the name of the content requested by the user to the in-system name and sends it to the file management unit 112. The file management unit 112 is a URL (Uniform Resource Loc) that is an address of one of the downloaded download files (CFAs 1 to m) of the content related to the in-system name.
ator) is designated (step S22), and the designated download file (CFAn) is distributed from the distribution server 131 to the user terminal 4 (step S23). In addition,
The download file (CFAn) is a content division file (CFCn) to which a redundant code that makes noise is added, as described above.

In the processes of steps S22 to S23, the user terminal 4 executes all the download files (CFA1 to CFA1).
Iterate until m) is obtained. Here, the order in which each download file CFAn (n is any integer from 1 to m and indicates the CFA number) is transmitted to the user terminal 4 is related to the order of the data forming the content file (CF). No irregular order. This is one of the methods for preventing unauthorized acquisition of the content file (CF) by an unauthorized access person or the like. Further, the distribution server 131 transmits various information about the content requested by the user to the user terminal 4 (step S2).
4).

When the user terminal 4 acquires all the download files (CFA1 to m), the user terminal 4 obtains all the download files (CFA1 to m) and various information indicating that the user terminal 4 is a valid user. Is transmitted to the pull-type delivery control unit 110 (step S25). Then, the pull-type delivery control unit 110 sends all the download files (CFA) to the legitimate user terminal 4.
1-m) is confirmed (authenticated). If the authentication is successful, the pull-type delivery control unit 110 transmits a list (redundancy code list) for removing the redundant code from the download files (CFA1 to m) to the user terminal 4 (step S26).

The user terminal 4 uses the received redundant code list to download each download file (CFA1 to m).
Remove the redundant code from the content division file (C
FC1-m) are obtained. Next, the user terminal 4 transmits information requesting decryption of the content division files (CFC1 to m) to the pull-type delivery control unit 110 (step S).
27).

Then, the pull-type delivery control unit 110 confirms (authenticates) whether or not the decryption request is from the valid user terminal 4. If the authentication is successful, the pull-type delivery control unit 110 determines the content division files (CFC1 to m).
The decryption key used for decryption and the combined key for combining the decrypted files are transmitted to the user terminal 4 (step S28).

The user terminal 4 uses the received decryption key to decrypt all the content division files (CFC1 to CFC) to form a division file group. Then, the user terminal 4 combines the divided file groups using the received combined key to obtain one content file (CF). In addition,
This content file (CF) is a file that can be played back by a general personal computer or the like.

Next, another process for content distribution in the pull-type distribution control unit 110 will be described with reference to FIGS. 8 and 9. FIG. 8 is a block diagram showing the connection relationship between the pull-type delivery control unit 110 and other systems.
FIG. 9 is a sequence diagram for explaining another process for content distribution performed by the content distribution system 2 shown in FIG.

First, the control unit 1 of the pull type distribution control unit 110.
Upon receiving the content acquisition request from the user terminal 4, the 11 selects the first CFA to be downloaded from the CFA 1 to m and notifies the user terminal 4 of the CFA number (steps S101, S102). In step S101, when a content acquisition request is issued from the user terminal 4, the user of the pull-type delivery control unit 110
The gateway server 140 (see FIG. 8) authenticates whether the content acquisition request is a valid request from the valid user terminal 4. This authentication is performed using the user database 141 that stores information about users who are valid for the content acquisition request.

Then, the control unit 111 sends CFAn (n is an integer of 1 to m, CFn from the user terminal 4).
Upon receiving the download request (indicating the A number), the file management unit (FM) 112 of the pull-type delivery control unit 110 is searched for a file management unit 112 that can respond to the supply of CFAn, and the corresponding file management is performed. The file management unit 112 with the lightest load is selected from the units 112 (step S103).

Next, the control unit 111 makes a download allocation request to the file management unit 112, and when the consent is obtained, notifies the user terminal 4 to access the file management unit 112 (steps S104 to S1).
06).

Next, when the file management unit 112 receives the CFAn download request from the user terminal 4,
CFA from among the distribution servers 131 of the distribution server group 130
distribution server 13 capable of responding to download of n
One is selected (step S107). Upon requesting the delivery server 131 to create a URL for downloading CFAn and receiving the notification of the URL, the URAL is notified to the user terminal 4 (steps S108 to S11).
0).

Then, when the distribution server 131 receives a CFAn download request from the user terminal 4 by specifying the URL, the CFAn file download is executed (steps S111 to S112). The user terminal 4 is
After completion of downloading the CFAn file, the completion notification is sent to the control unit 111 (step S113).

In the processing of steps S103 to S113, the user terminal 4 downloads all downloaded files (CFA1).
~ M) is repeated until the acquisition is completed. This allows
The user can obtain all the downloaded files (CFAs 1 to m) and obtain the content. The distribution server 131 deletes the URL after the download to the user terminal 4 is completed. This prevents unauthorized acquisition of the download file.

With these, the download file (C
Even if the FA is illegally acquired, it is virtually impossible for the illegal acquirer to restore the download file (CFA) to the original content file (CF). Therefore, the download file (CFA) is stored. Even if the distribution server 131 is directly connected to the user terminal 4 such as a personal computer, it is possible to prevent the content file (CF) from being illegally acquired.

Further, the pull type delivery control unit 110 shown in FIG.
A program for realizing the function of is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read by a computer system,
The content distribution process may be performed by executing the process. The term "computer system" used here means
It may include an OS and hardware such as peripheral devices. In addition, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used. Further, the “computer-readable recording medium” refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, or a storage device such as a hard disk built in a computer system.

Further, the "computer-readable recording medium" means a volatile memory (RAM) inside a computer system which serves as a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. ), Which holds the program for a certain period of time. The program may be transmitted from a computer system that stores the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the "transmission medium" for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. Further, the program may be a program for realizing some of the functions described above. Further, it may be a so-called difference file (difference program) that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like within the scope not departing from the gist of the present invention. included.

[0063]

As is apparent from the above description, according to the present invention, the image content consisting of image data is divided into a plurality of files, and noise is added to each divided file for encryption. If you do not take noise, it will be impossible to decrypt, but even if an unauthorized person tries to decrypt the divided file by estimating the noise, the original data is image data, so whether it was correctly decrypted or not It becomes impossible to understand, and it is possible to make meaningless unauthorized access to contents.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration example of a content illegal acquisition prevention system according to an embodiment of the present invention.

FIG. 2 is a sequence diagram for explaining a general operation of the above-mentioned illegal content acquisition prevention system.

FIG. 3 is a block diagram showing a configuration of a content distribution system 2, which is a main part of the above-mentioned illegal content acquisition prevention system.

FIG. 4 is a flowchart showing an operation of the content division file generation unit 100.

FIG. 5 is a table showing information about redundant codes included in a download file (CFA).

FIG. 6 is a block diagram showing functions of a control unit 111 and a file management unit 112.

FIG. 7 is a sequence diagram showing content distribution processing in the content distribution system 2 and content reproduction processing in the user terminal 4.

FIG. 8 is a block diagram showing a connection relationship between the pull-type delivery control unit 110 and other systems.

FIG. 9 is a sequence diagram showing another process for content distribution performed by the content distribution system 2.

FIG. 10 is a block diagram showing a schematic configuration of a conventional content distribution system.

[Explanation of symbols]

1 Content provider 2 Content distribution system 3 Internet 4 user terminals 100 Content division file (CFC) generation unit 110 Pull type delivery control unit 111 control unit (database control server) 112 File Management Department (File Management Server) 120 Push type delivery control unit 121 control unit (database control server) 122 File Management Unit (File Management Server) 130 distribution server (DS) group 131 Distribution server 140 user gateway server 141 user database

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G06F 17/60 512 G06F 17/60 512 H04K 1/02 H04K 1/02 H04L 9/08 H04L 9/00 601B (72) Inventor Takashi Kumahira 2-2-2 Otemachi, Chiyoda-ku, Tokyo Urbannet Otemachi Building, NTT TME Co., Ltd. (72) Hironobu Maebaba 2-2-Otemachi, Chiyoda-ku, Tokyo 2 Urbannet Otemachi Building F-term inside NT Tier Co., Ltd. (reference) 5B017 AA03 BA07 BA10 CA07 CA16 5B082 EA01 EA11 GA11 5B085 AE29 BA06 BG03 BG04 5J104 AA12 EA08 EA15 PA07

Claims (9)

[Claims] 1. A method for preventing unauthorized acquisition of content, which is used in a system for delivering content, wherein image content constituting at least one of the contents comprises image data, and the image content is stored in a plurality of files. A method for preventing unauthorized acquisition of content, characterized by dividing the file and adding noise to each of the divided files for encryption. 2. The illegal content acquisition preventing method according to claim 1, wherein the divided and encrypted files are stored in a database in an irregular order. 3. A management server that controls distribution of the content is divided into two layers, a database control server and a file management server, and the database control server is a name of the content and a name of the content in the system. 3. The content illegality according to claim 1 or 2, wherein the in-system name is managed in association with each other, and the file management server manages the in-system name and the storage location of the divided and encrypted file. Acquisition prevention method. 4. The database control server performs a predetermined process to convert a content name related to a user's content distribution request into the in-system name and sends the in-system name to the file management server, and the file management server in the system. When the database control server receives information indicating that all the divided files have been received from the user by performing control for delivering the divided and encrypted files of the content related to the name to the user, 4. The method for preventing illegal acquisition of content according to claim 3, wherein the database control server performs control for causing the user to transmit noise removal data for removing the noise. 5. The database includes information requesting transmission of a combining code for combining the divided files after the user removes noise from the divided and encrypted files using the noise removal data. The illegal content acquisition prevention method according to claim 4, wherein the illegal content acquisition is transmitted to a control server. 6. The distribution server having the divided and encrypted file, communicates with the terminal of the user, and distributes the file to the terminal of the user. The method for preventing unauthorized acquisition of content described in paragraph 1. 7. A content illicit acquisition prevention system that distributes content data from a distribution server to a user related to regular access, and invalidates content data acquired by means other than regular access, the image content including image data. Is divided into a plurality of files, and a content divided file generation unit is provided which has a content division file generation unit that adds noise to each divided file and encrypts the divided files. 8. The distribution server stores the divided and encrypted files in irregularly allocated locations, controls the distribution server, and includes a content name and a system of the content. A database control server that manages the system name, which is a name in the system, in association with each other, and a server that controls the distribution server and manages the system name and the storage location of the divided and encrypted files. The file illegal management system according to claim 7, further comprising: 9. A content illicit acquisition prevention program used in a system for delivering content, the method comprising: dividing image content consisting of image data forming at least one of the content into a plurality of files. A program for preventing unauthorized acquisition of content, characterized by causing a computer to execute a step of adding noise to each of the divided files and performing encryption.