JP2001211161A - Content distributing method, computer and device for content distribution system, and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a content distributing method which can prevent contents from illegally being used and can certify a content owner. SOLUTION: A content distribution system includes a content server device 2A which stores contents and a portable telephone set 5 which receives contents distributed from the content server device 2A. A characteristic telephone number is stored in the portable telephone set 5. The contents distributed from the content server device 2A are received by the portable telephone set 5 (step 63). The telephone number characteristic of the portable telephone set 5 is embedded in the received contents (step 64).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a content distribution method, a computer and an apparatus for a content distribution system, and a control method thereof.

[0002]

BACKGROUND OF THE INVENTION In recent years, with the spread of portable terminals represented by personal computers and mobile phones, various content distribution services have been provided regardless of whether they are for corporations or individuals.

In a content distribution service using a computer, the Internet, a communication satellite, or the like is used.
The content is provided from the service provider side to the user. In such a content distribution service, appropriate charging according to the usage mode of the content (period, content type, and the like) and prevention of unauthorized use of the distributed content are essential issues in commercial use.

[0004]

DISCLOSURE OF THE INVENTION An object of the present invention is to make it possible to easily set the types of contents that can be browsed for each customer.

Another object of the present invention is to prevent unauthorized use of distributed contents.

Another object of the present invention is to make it possible to prove that the user possesses the content to be distributed.

In a content distribution method according to the present invention, a content server computer encrypts a content to be distributed using a content key unique to the content to generate an encrypted content. Encrypt the content with a member key unique to each member who is eligible to receive the content, generate a content encryption key corresponding to each of the above members,
Encrypted content including the encrypted content and all content encryption keys generated for each member;
A file is created, and the created encrypted content file is delivered to the client computer of the member.

In the client computer receiving the encrypted content file, the content encryption key corresponding to the member included in the received encrypted content file is decrypted using the member key, and the content encryption key is decrypted. Key, and using the obtained content key,
Decrypt the encrypted content included in the received encrypted content file. Content includes programs,
Various information represented by document (text) data, moving image data, still image data, music (sound) data, their compressed data, or data (multimedia data) obtained by combining (synthesizing) them is included. .

In a content server computer (hereinafter simply referred to as a server), a member key is generally generated for each member. The member key may be generated in advance for all registered members, or each time content is distributed, a member key may be generated for members who are eligible to receive the content.

[0010] The member key is distributed in advance from a server to a client computer (hereinafter, simply referred to as a client). The member key may be sent to each member's client via the network, or a memory chip, F
D and the like, and may be mailed to the member. In distributing the member key, the member key can be encrypted (the encrypted member key is also referred to as a member key in this specification). In particular, the encryption of the member key is effective when the member key is distributed through the network. However, in this case, it is assumed that each member has a key for decrypting the encrypted member key (including distributing it in advance).

[0011] The client receives the encrypted content file. Receiving the encrypted content file
It may be a mode of downloading from a server or a mode of receiving a broadcast type sent from the server.
The encrypted content file includes a content encryption key and an encrypted content corresponding to all members who are eligible to receive the content. The member uses the client to decrypt the content encryption key using the client's own key. At this time, if the content encryption key and the member identification code are paired, the content encryption key can be easily found in the encrypted content file using the member identification code as a key. Yes (assuming that the member identification code has also been previously distributed or distributed to the member or its client). Even if the member identification code does not exist in the encrypted content file, the encrypted content can be decrypted. For example, at the client
It decrypts all the encrypted content keys in the encrypted content file using the member key unique to the client (member), and attempts to decrypt the encrypted content using the content key obtained by the decryption. Since one meaningful content should exist in the decrypted content, it can be seen that this content is correctly decrypted.

As described above, according to the present invention, the encrypted content file is encrypted with the member key of the member who is permitted to view (entitle to receive) the encrypted content included in the file. If only the content encryption key is included, only members permitted to view such content can decrypt the encrypted content and view the content.

[0013] Members who can browse can be set for each content. It is possible to prevent the members who are not qualified to view the contents from browsing. For example, it is possible to make it impossible for a member whose qualification has been deprived due to unpaid billing to view the content only by processing in the server.

In one embodiment of the present invention, the content
In the server computer, a pair of an identification code given to a member who is qualified to receive the content and a content encryption key corresponding to the member is included in the encrypted content file. The client computer extracts the content encryption key corresponding to the member from the encrypted content file using the identification code of the member corresponding to the client computer. The client computer adds a member identification code to the content obtained by decoding.

Preferably, the member identification code is added to the content by being embedded (inserted) as an electronic watermark in the content. Even if the content is copied and redistributed by the member, it is possible to identify who the member has distributed. Unauthorized use of content can be prevented.

The present invention also provides a content server computer suitable for a content distribution method.

The present invention further provides a content server
A medium on which a program for causing a computer to operate as described above is also provided.

The present invention also provides a content client device used in a content distribution system in which a content server device storing content and a content client device receiving distribution of content from the content server device can communicate with each other. Control method is provided.

According to a first method of controlling a content client device according to the present invention, a content client receives a content distributed from the content server device and embeds externally provided information in the received content. It controls the device.

According to a second method for controlling a content client device according to the present invention, the content received from the content server device is received, and the received content is stored in the content client device in advance. The content client device is controlled so that a unique identification code is embedded in the client device.

According to a third method of controlling a content client device according to the present invention, a content and an identification code unique to the content client device are received from the content server device, and the received content is added to the received content. Controlling the content client device so as to embed an identification code unique to the client device.

Contents are stored (registered) in advance in a content server device (hereinafter simply referred to as a server device). A content client device (hereinafter simply referred to as a client device) receives content from such a server device. Generally, a request indicating the content to be received in advance is transmitted from the client device to the server device, and the content having the content corresponding to the request is transmitted from the server device to the client device.

According to the first control method, the content client device embeds externally provided information in the received content. The information may be provided from an input device, or may be provided from another device or a recording medium. The information given from the outside includes information for identifying an individual or an affiliation of an individual, such as a name, an address, a telephone number, an electronic mail address, and other various information. When information for identifying an individual is embedded in content, it can be proved that the content is content owned by the user (for example, content purchased by the user).

According to the second control method, an identification code unique to the client device is stored in the storage device or the like in advance in the client device. The unique identification code may be transmitted from the server device to the client device (this is the third control method). The client device embeds the identification code in the content received from the server device.

The identification code unique to the client device is a code (for example, a product number) that is individually assigned to each client device when the client device is manufactured or shipped.
Or a rewritable code (number, character, symbol, etc.). Since the identification code is for identifying each client device, if the identification code is rewritable, a unique code is adopted for each client device. Even if the content is copied and redistributed, the client device (or its user) that has redistributed can be identified by the identification code. From the viewpoint of the user of the client device, it is possible to prove that the content distributed by the identification code belongs to the user.

When such a client device is a portable terminal represented by a portable telephone, the portable terminal has a code (a telephone number in the case of a portable telephone) capable of identifying each portable terminal. Since the number is stored in the memory in advance, such a number or the like can be used as an identification code.

In distributing the content, the server device may encrypt the content. In this case, the client device decrypts the encrypted content before embedding the identification code or information in the content.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment In a content distribution system, a content provider provides a user with various contents (stock price information, market analysis information, person information, etc.) via a communication line (wired communication line, wireless communication line) or the like. , Music information, etc.).

In the content distribution system according to the first embodiment, a user who can use the provided content (permitted to use the content) for each content provider and for each type of content provided by the content provider. User (hereinafter, referred to as a member) is specified in advance. The conditions for acquiring the content use qualification (qualification for becoming a member) are determined in advance by the content provider. In general, different memberships are determined by the content provider for each type of content (identified by differences in information, differences in the amount of information, differences in the quality of information, etc.) For example, conditions for obtaining qualifications (for example, paying a predetermined fee, reaching a predetermined age, etc.) are determined. According to a contract concluded between the user and the content provider, a membership is given to a user who satisfies the qualification acquisition condition for each content.

FIG. 1 shows the overall configuration of the content distribution system in the first embodiment.

This content distribution system comprises a server computer 2 and a plurality of client computers 3 mutually connected via a network 1. In this embodiment, the server computer 2
Is under the control of the content provider. The client computer 3 is under the control of a user who uses the content provided by the content provider.

The server computer 2 and the client computer 3 are a storage device for storing programs and data, a transmitting and receiving device for transmitting and receiving programs and data via the network 1, an input device for inputting data and the like, and a data device. Computer system including a display device for displaying an image (a personal computer,
Workstation, etc.). The network 1 includes both a public line (such as the Internet) and a dedicated line provided between these computer systems. Facilities and equipment (CA
TV facilities, broadcast satellites, communication satellites, etc.) are also included in the network 1. Communication devices used for transmitting and receiving data and the like are stored in storage devices of the server computer 2 and the client computer 3. When the network 1 is the Internet, a browser can be used as a communication program provided in the client computer 3. As will be described later, a program for controlling the server computer 2 and the client computer 3 includes a CD-ROM 22,
23, and are installed from the CD-ROMs 22 and 23 in the storage devices of the server computer 2 and the client computer 3, respectively.

In the storage device of the server computer 2,
An encrypted content database 30 is stored.
The encrypted content database 30 stores encrypted content (still image data, stock image information, market analysis information, personal information, etc., moving image data, music data, audio data, document data, programs, Compressed data, their combined data, etc.) are stored.
By using a communication program (such as a browser)
The client computer 3 can access the encrypted content database 30 stored in the storage device of the server computer 2.

FIG. 2 shows the server computer 2 and the client computer 3 which constitute the content distribution system, from the viewpoint of creating an encrypted content database in the server computer 2 and the client computer.
These are shown from the viewpoint of the decryption processing of the encrypted content in the computer 3. Since a plurality of client computers 3 basically perform the same operation, only one client computer 3 is shown.

First, a flow of creating the encrypted content database 30 in the server computer 2 will be described. FIG. 3 is a flowchart showing the flow of the process of creating the encrypted content database in the server computer 2.

The server computer 2 has stock price information,
Depending on the type of information such as market analysis information, person information, music information, etc., the amount of information, the quality of information, etc.
= 1 to m) are prepared.

For each content, a content key j unique to the content is prepared (generated). For the content j, a content k key kj unique to the content j is prepared. The server computer 2 performs an encryption process for encrypting the data with an encryption key to create encrypted data. The content j is encrypted through an encryption process using the content j key kj (step 31). The encrypted content j is called an encrypted content ej.

As described above, in the content distribution system, a member who can use the content is specified in advance for each content. A unique member key ki is prepared (generated) for each member i who can use the content j (i = 1 to n).

The member key ki generated for each member i is
In the server computer 2, the encrypted content e
It is used to encrypt the content j key kj used to generate j. The key kj for the content j is encrypted by an encryption process using each of the member keys ki (step 32). The key kj for the content j encrypted using the member key ki is replaced with the encryption key kij for the content j.
Call. If there are a plurality of members i who can use the content j, a plurality of member keys kij are generated, so that a plurality of content j encryption keys kij are also generated.

The member key ki is further distributed to each of the members i. The member key ki is delivered to the member i by mail (eg, by mailing a floppy (registered trademark) disk in which the member key ki is recorded) or by writing (letter, fax, etc.).

The encrypted content ej and the content j encryption key kij are combined into one file (step
33). Copy this file to the encrypted content file Fj
Call.

The encrypted content file Fj has, for example, a data structure in which the encrypted content ej is the main data, and the encryption key kij for the content j is a part of the header information. Encrypted content file Fj
Is the same number of content j as the number of members using content j
Encryption key kij.

As described above, the content j encryption key kij is obtained by encrypting the content j key kj using each of the member keys ki. For example, the key length of the content j key kj is In the case of 8 bytes, if the number of members who use the content j is 1000, the total data amount of the encryption key kij for the content j is about 8000 bytes (8 kB). The amount of data occupied in the encrypted content file Fj by all the content j encryption keys kij of the user i of the content j is determined by the storage devices (hard disk, C
This is not excessive considering the recordable data capacity of a D-ROM or the like. Compared to the data amount occupied by the encrypted content ej in the encrypted content file Fj,
The ratio of the data amount occupied by the content j encryption key kij is small.

The encrypted content file Fj thus created is stored in the encrypted content database.
It is registered (stored) in 30 (step 34).

Content j encryption processing, content j
Processing of the encryption key kj, encrypted content file F
It is not always necessary to use the server computer 2 for all of the process of creating j and the process of registering the encrypted content file Fj in the encrypted content database. Some or all of these processes may be performed using another computer system. In any case, an encrypted content database 30 in which the encrypted content file Fj created by the above-described encrypted content database creation process is registered in the storage device of the server computer 2 in advance. .

Next, the client (member) on the member side (user)
The decoding process in the computer 3 will be described.

The storage device of the client computer 3 stores a communication program (browser or the like) in advance. The member using the content j accesses the encrypted content database 30 stored in the storage device of the server computer 2 using a browser,
The encrypted content file Fj registered in the encrypted content database 30 is downloaded. The encrypted content file Fj is transferred to the storage device of the client computer 3.

The client computer 3 is provided with a decoding program in advance by downloading it from the server computer 2 or another computer system connected to the client computer 3 via the network 1. The decryption program may be in the form of a plug-in that operates integrally with the browser. The plug-in format decryption program uses a browser to encrypt the encrypted content file F
The client computer 3 starts up in response to the download of j.

FIG. 4 is a flowchart showing the flow of the processing of the decryption program.

As described above, the user key (ki) of the user of the client computer 3 (the member who uses the content j) is distributed in advance. When the decryption program is started, the member key ki is read (for example, from a storage device or FD) (step 41).

The encryption key kj for the content j included in the encrypted content file j includes the encryption key for the content j, which is encrypted using the member key ki of the member i who can use the content j. The key kij is included. Using the read member key ki, the content j encryption key kij is decrypted according to the processing of the decryption program. The key jj for the content j is obtained (step 4)
2).

Further, the decrypted program decrypts the encrypted content ej contained in the encrypted content file Fj using the obtained content j key kj (step 43). The encrypted content ej is decrypted,
The content j is obtained. The user obtains the content j (still image data, moving image data, audio data, document data, etc.).

When a member who uses the content j is added, the server computer 2 encrypts the content j key kj using the member key ki to generate a new content j encryption key kij. Generated content j
The encryption key kij for use may be added to the encrypted content file Fj. Conversely, when the membership of the content j is to be deprived due to the nonpayment of the fee, the expiration of the contract period, etc., the encryption key kij for the content j of the member may be deleted from the encrypted content file Fj. . Member management can be easily performed in the server computer 2.

When the content j is changed (for example, information is updated), the server computer 2
, The encrypted content ej included in the encrypted content file Fj may be replaced with the encrypted content ej obtained by encrypting the new content using the content k key kj.

Even if a person other than the member who uses the content j downloads the encrypted content file j from the encrypted content database 30, the encryption key kij for the content j necessary for decrypting the encrypted content ej is obtained. , Other than members are not included in the encrypted content file Fj. Even if a person other than the member who uses the content j downloads the encrypted content file Fj, the content j cannot be used (viewed or the like) after all.

In the above embodiment, the member i
Although the encrypted content file Fj is downloaded from the server computer 2 using the computer 3, in the case of a data broadcasting format using a broadcasting satellite, a communication satellite, or the like, the encrypted content file Fj is stored in the server.
Since the data is transmitted (broadcast) from the computer 2 to the client computer 3, downloading is not necessarily required.

FIG. 5 shows a modification of the first embodiment.
The server computer 2 and the client computer 3 are connected with each other in terms of the creation of an encrypted content database in the server computer 2 and the client computer.
These are shown from the viewpoint of the decryption processing of the encrypted content in the computer 3. 2 differs from FIG. 2 in that IDs are assigned to each of the member keys ki and the content j encryption keys kij, and the processing of the decryption program executed in the client computer 3 (to be described in detail later). different.

A pair of member key ki and IDi is generated.
The IDi paired with the member key ki is, for example, a combination of numbers, characters, symbols, etc. for identifying each member. A pair of member keys ki and IDi are distributed to the member i.

Using the member key ki, the content j key k
Content j generated by encrypting j
The encryption key for key kij is also paired with the IDi assigned to the key for member ki. Encrypted content file F
j includes a pair of IDi and an encryption key kij for content j.

FIG. 6 is a flowchart showing the processing of the decryption program executed in the client computer 3 shown in FIG. In FIG. 6, step 43 is
Since the processing is the same as the processing of the decoding program shown in FIG. 4, the same reference numerals are given, and duplicate detailed description will be omitted.

As described above, a pair of the IDi and the member key ki is distributed to the user of the client computer 3 (member of the content j). IDi
And the member key ki are read from the storage device or the like (step
51).

The encrypted content file Fj includes a plurality of IDi for members i who can use the content j.
And an encryption key kij for the content j. When the IDi and the member key ki are read, the decryption program uses the read IDi as a key and uses the same ID.
i is searched (step 52). Searched content j
Encryption key kij for a plurality of contents j
Extracted from

The extracted content j encryption key kij
Is decrypted using the member key ki (step 53).
Using the content j key kj obtained by decryption,
The encrypted content ej is decrypted. The user obtains the content j (step 43).

Further, processing for embedding IDi in the content j obtained by decryption is performed by the decryption program (step 54).

When IDi is embedded in content j,
The processing of the decryption program ends. FIG. 7 (A) shows an example of a data embedding technique using an electronic watermarking method.
Here, the image content in which “Patent Ichiro” is embedded is conceptually shown. FIG. 7B shows the image content from which IDi has been extracted. In FIG. 7A, the state in which the character is embedded in the image by the digital watermark is shown by oblique lines for easy understanding (the oblique lines are not visible in the actual image). When the content is image data, the embedding of data by the digital watermarking method includes density pattern method, dither method, error diffusion method, pixel replacement type, pixel space use type, quantization error use type,
A method such as a frequency domain type or a statistic type can be used. In the case of audio (music) data, a scramble signal, a phase component, a dither signal, adaptive PCM quantization,
Speech masking, predictive code run length, vector quantization, excitation pulse, etc. can be used. In the case of document data, a line spacing control method, a word spacing control method, or the like can be used.

By performing data extraction processing corresponding to data embedding processing by the decryption program, IDi
IDi can be extracted from the content (FIG. 7 (A)) in which is embedded (FIG. 7 (B)).

Depending on the content provided by the content provider only to a specific member, the member can freely use the content (for example, reuse the content (the member copies the content obtained from the content provider and resells the content (re-use)). Distribution) etc.) may be restricted. When such an act is performed, the ID embedded in the content can be used to identify the member who resells the content. By extracting the ID from the content in which the redistributed ID is embedded, it is possible to specify the member who is redistributing the content.

Second Embodiment FIG. 8 shows the overall configuration of a content distribution system according to a second embodiment. The same components as those of the content distribution system of the first embodiment are denoted by the same reference numerals.

This content distribution system comprises a server computer 2 A and a plurality of mobile phones 5 connected to each other via a network 1.

The server computer 2A is a computer system having the same hardware configuration (storage device, transmission / reception device, input device, output device, etc.) as the server computer 2 of the first embodiment. The content database 30A is stored in the storage device of the server computer 2A.
Is stored. This content database 30A
Has a plurality of contents stored (registered) in advance. The server computer 2A performs the above-described encryption processing of the server computer 2 (encryption of the content using a content key unique to the content to create encrypted content, and qualification for receiving the content with the content key). A process of generating a content encryption key corresponding to each member by encrypting each member with a member key unique to each member, and a file creation process are not necessarily performed.・
Different from computer 2.

The plurality of portable telephones 5 basically have the same electrical configuration. One of the plurality of mobile phones 5 is denoted by reference numeral 5A.

FIG. 9 is a block diagram showing an electrical configuration of the mobile phone 5A. A control circuit 10 is built in the mobile phone 5A, and a transmission / reception circuit 11, an internal memory 12, a memory
13, an audio processing circuit 14, an input device 15, a display device 16, and a memory card connector 19 are connected to each other.
A speaker 17 and a receiver 18 are connected to the audio processing circuit 14, respectively. An antenna 21 is connected to the transmission / reception circuit 11.

The operation of the portable telephone 5A is controlled by the control circuit 10. The control circuit 10 includes a central processing unit and its input / output interface circuit. The central processing unit is a programmed computer (especially a microprocessor)
It is realized by. The internal memory 12 stores a program for controlling the processing operation of the central processing unit, a work area, and the like.

The portable telephone 5A is basically used for transmitting and receiving voice data to and from another portable telephone 5 and ordinary telephone equipment. When a telephone number of the other party's mobile phone 5 or the like is input using an input device (dial button, numeric keypad, etc.) 15, data representing the input telephone number is transmitted via a control circuit 10, a transmission / reception circuit 11 and an antenna 21. To the base station (exchange station). When the line is connected to the other party's mobile phone 5 or the like, the mobile phone 5A and the other party's mobile phone 5
The transmission and reception of audio data is performed with the above.

The audio data received through the antenna 21 and the transmission / reception circuit 11 is decoded by the audio processing circuit 14. When the decoded audio signal is provided to the speaker 17, the voice of the other party can be heard from the speaker 17. When a word (voice) is emitted toward the receiver 18, the voice is encoded by the voice processing circuit 14 and output from the voice processing circuit 14 as voice data. Voice data is a control circuit
10, the transmission / reception circuit 11 and the antenna 21 are transmitted to the other party's mobile phone 5 or the like.

The memory 13 stores a browser, an embedded program, and data representing a telephone number. These programs and data can be installed in the memory 13 of the mobile phone 5A via the memory card 20.

The browser is a communication program used to connect the mobile phone 5A to the server computer 2A via the network 1. By using the browser, it is possible to access the content database 30A stored in the storage device of the server computer 2A that provides the content. Various types of data (image data, character data, music data, etc.) stored as contents in the content database 30A
Is transmitted to the mobile phone 5A via the network 1. The image represented by the image data, the character represented by the character data, and the like can be displayed on the display screen of the display device 16.

The embedding program is a program for performing processing for embedding telephone number data in contents downloaded from the server computer 2A.

The telephone number is a number previously assigned to each of the portable telephones 5 and 5A. Data representing a telephone number (hereinafter referred to as telephone number data) is assigned to each of the mobile phones one by one, and stored in the memory 13 in advance. Since the mobile phones 5 and 5A are basically owned by individuals, a person (owner) can be specified by a telephone number.

The memory card connector 19 is
This is a connector for connecting the card 20. The content downloaded from the server computer 2A can be stored in the memory card 20 connected to the memory card connector 19, or the content stored in the memory card 20 can be read.

FIG. 10 is a flowchart showing an example of the operation flow of the mobile phone based on the browser and the embedded program. The embedded program is basically a separate program from the browser, but is executed integrally with the browser.

When the user of the mobile phone 5A activates the browser using the input device 15 (or requests connection), the telephone number data of the mobile phone 5A and the data representing the display request of the content menu are stored in the mobile phone 5A.
A is transmitted from A to the server computer 2A.
The server computer 2A receives the received mobile phone 5A.
Then, data representing a content menu is transmitted to the mobile phone 5A based on the telephone number data of (1). Mobile phone 5A receiving data representing content menu
A menu screen showing a list of downloadable content names is displayed on the display screen of the display device 16 (step 61).

Using the input device 15, the user of the mobile phone 5A selects a content name requested to be downloaded from the content names displayed on the menu screen (step 62). The data requesting the download of the selected content is stored in the server computer 2A.
Sent to In the server computer 2A that has received the download request data, the content selected by the user is stored in the content database 30A.
Is read from. The content is downloaded to the mobile phone 5A (step 63).

The contents downloaded from server computer 2A are stored in internal memory 12 of mobile phone 5A.
Is stored temporarily.

When the download of the content is completed,
The telephone number data stored in the memory 13 in advance is read into the internal memory 12. Here, the embedding program is executed. Based on the embedding program, data representing a telephone number is embedded in the downloaded content (step 64). The contents in which the telephone number data is embedded are stored in the control circuit 10 and the memory card connector.
The data is stored in the memory card 20 connected to the memory card connector 19 via the memory card connector 19.

Thus, the server computer 2
The phone number data of the mobile phone used for the download is embedded in the content downloaded from A to the mobile phone 5A. As described above, the mobile phones 5, 5
Since A is basically owned by each individual, the individual can be specified by the telephone number. Therefore, even if the downloaded content is copied and redistributed, if the telephone number data is extracted from the content in which the redistributed telephone number data is embedded, who can redistribute it? Can be specified. Unauthorized use of content can be prevented. Conversely, for the user of the mobile phone 5A, using the telephone number data embedded in the content to prove that the downloaded content is his / her own (for example, the content that he / she purchased). Can be.

As a modification of the second embodiment, the encrypted content (encrypted content) may be registered in the database 30A stored in advance in the storage device of the server computer 2A. FIG. 11 is a block diagram showing an electrical configuration of a mobile phone 5B in this modification. The electrical configuration of the mobile phone 5A shown in FIG.
The difference is that a decryption program is further stored in the memory 13. FIG. 12 is a flowchart showing the flow of the operation of the mobile phone 5B in this modification. The flowchart shown in FIG. 10 refers to the processing (step 7
The difference is that 1) is added. In the following description, the same components (processes) as those shown in FIGS. 9 and 10 are denoted by the same reference numerals, and redundant description will be avoided.

The mobile phone 5B stores the encrypted content selected by the user on the server computer 2A.
(Step 63). The downloaded encrypted content is temporarily stored in the internal memory 12.

The decryption program is executed. The decryption program is a program for decrypting the encrypted content temporarily stored in the internal memory 12 based on the decryption key to obtain the content. The decryption key used for decryption is distributed in advance from the content provider to the user. The distributed decryption key is input to the mobile phone 5B by the user using the input device 15 when the encrypted content is decrypted by the decryption program (the decryption key is stored in the memory 13 and the decryption key is used. Good). The encrypted content is decrypted by the decryption program based on the input decryption key (step 71). The decrypted content is stored in an area of the internal memory 12 different from the area where the decryption processing has been performed. An internal memory different from the internal memory 12 in which the decryption process is performed may be separately prepared, and the decrypted content may be stored therein.

The telephone number data is embedded in the content decrypted by the decryption program based on the embedding program (step 64). The content in which the telephone number data is embedded is recorded on the memory card 20 (step 65).

Since the contents distributed by the server computer 2A are encrypted at the time of distribution, even if a person other than the user to whom the decryption key is given in advance downloads the encrypted contents,
The content cannot be used. It is possible to prevent unauthorized use of contents due to unauthorized interception.

As data to be embedded in the content, data input by a user from an input device (such as a button) of the client computer 3 or the mobile phones 5A and 5B may be used. By inputting data from the input device as a code, number, symbol, or a combination thereof that can identify an individual, such as his / her name, e-mail address, ID, member number, etc., the content is his / her own. You can prove it.

In the above-described embodiment, the computer system and the mobile phone are used for receiving the content and embedding the data in the received content. However, the electronic organizer, the in-vehicle navigator device, the game device, other electronic devices, and the mobile terminal are used. Can be used as a device for receiving content and embedding data in the received content.

[Brief description of the drawings]

FIG. 1 shows an overall configuration of a content distribution system according to a first embodiment.

FIG. 2 shows a server computer and a client computer from the viewpoint of creating an encrypted content database for the server computer and from the viewpoint of decryption processing of the encrypted content file for the client computer.

FIG. 3 is a flowchart showing a flow of a process of creating an encrypted content database by a server computer.

FIG. 4 is a flowchart showing a flow of processing of a decryption program.

FIG. 5 shows a modification of the first embodiment, in which a server computer and a client computer are used, and for a server computer, encrypted content is used from the viewpoint of creating an encrypted content database; -From the viewpoint of file decryption processing, each is shown.

FIG. 6 is a flowchart illustrating a flow of processing of a decryption program in a modification of the first embodiment.

FIG. 7A shows an image in which watermark information is embedded.
(B) shows an image in which watermark information is extracted from the image shown in (A).

FIG. 8 shows an overall configuration of a content distribution system according to a second embodiment.

FIG. 9 is a block diagram showing an electrical configuration of the mobile phone.

FIG. 10 is a flowchart showing the flow of the operation of the mobile phone.

FIG. 11 is a block diagram showing another example of the electrical configuration of the mobile phone.

FIG. 12 is a flowchart illustrating another example of the flow of the operation of the mobile phone.

[Explanation of symbols]

 1 Network 2 Server computer 3 Client computer 5, 5A, 5B Mobile phone 10 Control circuit 13 Memory 14 Voice processing circuit 19 Memory card connector 20 Memory card 22, 23 CD-ROM 30 Encrypted content database 30A Content・ Database

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 7/167 Z

Claims (15)

[Claims] 1. A content server computer encrypts a content to be distributed using a content key unique to the content to generate an encrypted content, and uses the content key to qualify to receive the content. Each of the members is encrypted with a member key unique to each member, and a content encryption key corresponding to each of the members is generated. The encrypted content and all of the content encryption keys generated for each of the members are combined with each other. The encrypted content file is created, and the created encrypted content file is distributed to the client computer of the member, and the client computer that has received the encrypted content file uses the member key. , To the member included in the received encrypted content file A content distribution method for decrypting a corresponding content encryption key to obtain a content key, and using the obtained content key to decrypt encrypted content included in a received encrypted content file. 2. An encrypted content generating means for encrypting a content to be distributed using a content key unique to the content to generate an encrypted content, and providing the content key to a member who is qualified to receive the content. Content encryption key generation means for encrypting the content with a unique member key to generate a content encryption key corresponding to each of the members, and the encrypted content generated by the encrypted content generation means Content in a content distribution system, comprising: an encrypted content file creating means for creating an encrypted content file including all content encryption keys generated for each member by the content encryption key generating means. -Server computer. 3. A content to be distributed is encrypted using a content key unique to the content to generate an encrypted content, and the content key is assigned to a member who is qualified to receive the content. Encrypting each member with a key to generate a content encryption key corresponding to each of the members; and encrypting the encrypted content file including the encrypted content and all the content encryption keys generated for each member. A recording medium storing a program for controlling a content server computer to be created. 4. An encrypted content file including a pair of an identification code given to a member who is entitled to receive content distributed from a content server computer and the content encryption key corresponding to the member. A program for controlling a receiving client computer, wherein the client uses a member identification code corresponding to the client computer to extract a content encryption key corresponding to the member from the encrypted content file. -A recording medium on which a program for controlling a computer is recorded. 5. A method for controlling a portable terminal used in a content distribution system in which a content server device storing contents and a portable terminal receiving distribution of contents from the content server device can communicate with each other. A method of controlling the mobile terminal, receiving the content distributed from the server device, and controlling the mobile terminal so as to embed the identification code unique to the mobile terminal stored in the mobile terminal in the received content in advance; . 6. The mobile terminal according to claim 5, wherein the content is encrypted and stored in the content server device, and the received encrypted content is decrypted before embedding an identification code in the content. Control method. 7. A portable terminal used in a content distribution system in which a content server device storing contents and a portable terminal receiving distribution of contents from the content server device can communicate with each other. Storage means for storing a unique identification code, reception means for receiving the content distributed from the content server device, and content received by the reception means, the content being unique to the portable terminal stored in the storage means A portable terminal having an embedding means for embedding an identification code. 8. A method for controlling a content client device used in a content distribution system in which a content server device storing content and a content client device receiving distribution of content from the content server device can communicate with each other. A content client device control method, comprising: receiving a content distributed from the content server device; and controlling the content client device so as to embed externally provided information in the received content. 9. A method for controlling a content client device used in a content distribution system in which a content server device storing content and a content client device receiving distribution of content from the content server device can communicate with each other. The content client device receives the content distributed from the content server device, and embeds the identification code unique to the content client device stored in the content client device in advance in the received content. For controlling a content client device. 10. A content server device storing an identification code for identifying a content and a content client device, and a content client device receiving distribution of the content and the identification code from the content server device can communicate with each other. A method for controlling a content client device used in a content distribution system, comprising receiving a content and an identification code unique to the content client device from the content server device, and adding the received content to the received content. A content client device control method for controlling the content client device so as to embed a unique identification code in the client device; 11. The content server according to claim 8, wherein the content is encrypted and stored in the content server device, and the received encrypted content is decrypted prior to embedding control of information or an identification code in the content. A method for controlling a content client device according to any one of the preceding claims. 12. A content client device used in a content distribution system in which a content server device storing content and a content client device receiving distribution of content from the content server device can communicate with each other, A content client device comprising: receiving means for receiving content distributed from the content server device; and embedding means for embedding externally provided information in the content received by the receiving device. 13. A content client device used in a content distribution system in which a content server device storing content and a content client device receiving distribution of content from the content server device can communicate with each other, Storage means for storing an identification code unique to the content client device, reception means for receiving content distributed from the content server device, and content received by the reception means, A content client device comprising an embedding means for embedding the identification code. 14. A content server device storing an identification code for identifying each of a content and a content client device and a content client device receiving distribution of the content and the identification code from the content server device can communicate with each other. Client device used in a simple content distribution system, the first receiving means for receiving content distributed from the content server device, and unique to the content client device distributed from the content server device. And a embedder for embedding the identification code received by the second receiver in the content received by the first receiver.
Client device. 15. A program for controlling a mobile terminal used in a content distribution system in which a content server device storing content and a mobile terminal receiving distribution of content from the content server device can communicate with each other, A program for controlling the mobile terminal to receive the content distributed from the content server device and to embed an identification code unique to the mobile terminal stored in the mobile terminal in advance in the received content is recorded. Recording medium.