JP2006092293A - Method for controlling content distribution use - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To permit a browsing permitted user to browse obtained content even in an off-line environment, and eliminate troublesome work for embedding rules on use in content for a user who will register the content. <P>SOLUTION: A method for controlling content distribution use includes: a step that a first client registers content with a server, in response to the operation of a first user; a step that the server embeds rules on use previously registered with the server in the content, in response to the operation of a second user to acquire the content from the server by using a second client; a step that the second client acquires the content with the rules on use embedded therein from the server; and a step that the second client, according to the rules on use, controls the use of content by the second user. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a content distribution use control method for distributing content to a specific user on a network and permitting use in a specific usage form corresponding to the user.

  A DRM (Digital Right Management) technique is known as a control technique for distributing content to a specific user on a network and permitting use in a specific usage form corresponding to the user. And a content distribution use control method applying this DRM technology has been proposed (for example, see Patent Document 1).

  In this method, a user ID is registered in advance in the ticket server, and a usage rule is registered in the ticket server when a document file is registered in the document server. The document file downloaded by the user is encrypted, and when the user performs an operation to open the encrypted file, the client sends the document ID of the file and the user certificate (user ID is the user ID) to the ticket server. Included). The ticket server determines the usage rule set in the document from the user ID and transmits it to the client. The client decrypts the document according to the received usage rule and presents it to the user.

  There is also a method in which the user embeds usage rules in the content itself at the time of content creation. Examples include Adobe Acrobat from Adobe Systems and DocuWorks from Fuji Xerox. These convert contents into PDF format (in the case of Acrobat) or DocuWorks format, and embed usage rules such as setting a password for viewing, whether printing, copying, editing, and the like.

JP2004-30056

  In the former method, it is necessary to obtain usage rules from the server when browsing content, so even if a user who is allowed to browse browses content that has already been acquired, it is necessary to access the server without fail. There is a problem that the content cannot be browsed when the client used at home or away from the office is not connected to the network or when the server is stopped due to a failure or the like.

  On the other hand, in the latter method, it is necessary to embed usage rules in the content itself at the time of content creation. Therefore, each time content is distributed, the content registrant needs to set usage rules for the content. There is a problem that the overhead of operation is large, for example, when contents are repeatedly delivered.

  The present invention has been made in order to solve the above-described problems. The purpose of the present invention is to enable a user who is permitted to browse to browse already acquired content even in an offline environment. The present invention provides a content distribution usage control method that allows a registered user to save the trouble of embedding usage rules in content.

  The content distribution usage control method according to the present invention includes a step in which a first client registers content in a server in response to an operation of a first user, and a second user uses a second client. In response to an operation for acquiring content from the server, the server embeds the usage rule registered in advance in the server in the content, and the second client acquires the content in which the usage rule is embedded from the server. And a step in which the second client controls the use of the content for the second user according to the usage rule. Other features of the present invention will become apparent below.

  According to the present invention, a user who is permitted to browse can browse the already acquired content even in an offline environment, and the user who registers the content can eliminate the trouble of embedding the usage rule in the content.

  FIG. 1 is a block diagram showing a schematic configuration of a content distribution use control system according to an embodiment of the present invention. As illustrated, a plurality of clients 11 to 1N are connected to the server 3 via the network 2. The usage rule 4 is registered in the server 3 in advance.

  The operation of the system of FIG. 1 will be briefly described. First, the first user 101 registers content in the server 3 using the first client 11. Then, the second user 102 acquires content from the server 3 using the second client 12. Accordingly, the first user 101 can distribute the content to the second user 102, and the second user 102 can use the distributed content.

  However, in response to an operation in which the second user 102 acquires content from the server 3, the server 3 embeds the usage rule 4 in the content already registered by the first user 101, and the second client 102 12 to send. Then, when the second user 102 who has received the content opens the content, the usage rule is applied, and therefore the second user 102 can execute only an operation permitted in advance.

  In addition, when viewing of the content is prohibited for users other than the second user 102 according to the usage rules, even if a third-party user 10N obtains the content by some means, the content Cannot be viewed.

  The operation of the system in FIG. 1 will be described in more detail with reference to FIG. However, the operation of the system will be described in four stages: “preparation”, “content registration process”, “content acquisition process”, and “content use”.

(Advance preparation)
First, as advance preparations, a set of a private key and a digital certificate used in PKI (Public Key Infrastructure) is obtained beforehand from CA (Certification Authority) for the users 101 and 102 and the server 3. Get issued. That is, the first and second clients 11 and 12 perform mutual authentication with the server 3 and exchange encryption keys before communication with the server 3, respectively. Thereby, when communicating with the server 3, the encryption communication session can be established using the encryption key.

  However, for mutual authentication between the first and second clients 11 and 12 and the server 3, a digital certificate that guarantees the validity of the public keys owned by the first and second users 101 and 102, respectively. A public key cryptosystem using a digital certificate that guarantees the validity of the public key owned by the server 3 is used.

  A set of the user's private key and digital certificate is written in the tokens 61 and 62. However, a hard disk or a portable medium may be used in place of the token as the storage location of the user's private key and digital certificate set.

  A plurality of folders are registered in advance in the server 3. In addition, each folder has a table in which folder characteristics are defined. The usage rule 4 is defined as the folder characteristic. The usage rule 4 is registered by the system administrator using the administrator device 5. Alternatively, the first user (content registrant) 101 may register the usage rule 4.

  FIG. 3 is a diagram illustrating an example of a table defining folder characteristics. For each folder, a list of user names that can use the folder and a usage rule registered in the folder for the user are described. As shown in FIG. 3, users “A”, “B”, “C”, and “M” can access “Folder X”. In addition, when the user “C” acquires the content registered in “folder X”, it indicates that the usage rule III is applied to the content.

  In the example of FIG. 3, the relationship between folder name-user name-usage rules is defined in the table. However, in order to use it for general purposes, user attributes such as job title and organization are assigned instead of the user name. It may be defined. In this case, for mapping between the user name and the user attribute, user information described in the user's digital certificate is used, or a table or database for associating both is prepared.

  FIG. 4 is a diagram illustrating an example of a table in which usage rules are defined, and the usage rules include “folder restrictions” and “content restrictions”.

  “Restrictions on folders” include “acquisition authority” that has the authority to acquire the contents registered in the folder, “new registration authority” that has authority to register new contents in the folder, There is an “overwrite registration / deletion authority” having the authority to register and the authority to delete contents.

  On the other hand, in the “restriction regarding content”, “browsing authority” having an authority to view the content acquired from the folder, “printing authority” having an authority to print the content acquired from the folder, and content acquired from the folder There is a “transcription authority” that has the authority to transcribe, and an “edit authority” that has the authority to edit the content acquired from the folder. Here, the “browsing authority” is an authority that only the received user can decrypt the content because the content is encrypted and distributed. In FIG. 4, “◯” means “having the authority”, and “×” means “no authority”.

  For example, in the example of FIG. 3 described above, the “use rule III” is applied to the user “C” with respect to the “folder X”. From FIG. 4, the user “C” has the authority to acquire the contents registered in “folder X”, but does not have the authority to newly register contents and register / delete overwriting contents. In addition, when the user “C” acquires content registered in “folder X”, the user “C” has the right to “browse” and “print” the content, but has the authority to “transcribe” and “edit”. I don't have it.

(Content registration process)
When registering the content, the first user 101 inserts the token 61 into the first client 11 and logs in to the server 3 (step 1001). At this time, a session for encrypted communication is established between the first client 11 and the server 3 by using the digital certificate of the first user 101 stored in the token 61 and the digital certificate of the server 3. (For example, SSL communication). Thereby, subsequent communication becomes encryption communication.

  In the process of establishing a cryptographic communication session between the first client 11 and the server 3, the server 3 acquires the digital certificate of the first user 101. Next, the server 3 extracts the user name of the first user 101 from the digital certificate of the first user 101. Then, the server 3 searches the table based on the user name of the first user 101, creates a list in the table that displays only the folders that the first user 101 is permitted to use, Transmit to the first client 11. As a result, a user who does not have the folder acquisition authority cannot see the contents of the folder, so that security can be ensured.

  For example, assuming that the user name of the first user 101 is “A”, in the example of FIG. 3, “A” is described in “folder X”, “folder Y”, and “folder Z”. The folder list is “folder X”, “folder Y”, and “folder Z”.

  The first user 101 confirms the folder characteristics of the folder list displayed on the first client 11, confirms the user name of the second user 102 who distributes the content, and the usage rules for the user. , Select a folder. Next, a content registration operation is performed on the folder (step 1002).

  For example, assuming that the user name of the second user 102 is “B”, “browsing” and “printing” of the content are permitted for “B”, and “transfer” and “editing” are prohibited. If it is desired to restrict usage, the content may be registered in “Folder X”. On the other hand, if the user wants to restrict usage that allows “viewing” of the content but prohibits “printing”, “transcription”, and “editing”, the content may be registered in “folder Y”.

  Next, in response to the operation of the first user 101, the first client 11 uploads the content designated by the first user 101 to the designated folder of the server 3 (step 1003). The uploaded content 7 is registered in the folder of the server 3 (step 1004).

  Further, in response to step 1004, the server 3 notifies all users' clients registered in the folder that the content has been registered by e-mail. As a result, it is possible to simplify subsequent content acquisition operations.

  For example, as the notification content of the e-mail, the name of the first user 101, the name of the folder in which the content is registered, the name of the content, the outline of the content, and the storage location of the content are described. Then, by describing the storage location of the content in a URL (Uniform Resource Locator) format, the second user 102 can select it and directly access it.

(Content acquisition process)
When acquiring content, the second user 102 inserts the token 62 into the second client 12 and logs in to the server 3 (step 1005). At this time, a session for encryption communication is established between the second client 12 and the server 3 by using the digital certificate of the second user 102 stored in the token 62 and the digital certificate of the server 3. To do. Thereby, subsequent communication becomes encryption communication.

  In the process of establishing a cryptographic communication session between the second client 12 and the server 3, the server 3 first acquires the digital certificate of the second user 102. Next, the server 3 extracts the user name of the second user 102 from the digital certificate of the second user 102. Then, the server 3 searches the table based on the user name of the second user 102, creates a list in the table that displays only the folders that the second user 102 is permitted to use, Transmit to the second client 12. As a result, a user who does not have the folder acquisition authority cannot see the contents of the folder, so that security can be ensured.

  For example, assuming that the user name of the second user 102 is “B”, in the example of FIG. 3, “B” is described in “Folder X” and “Folder Y”. “Folder X” and “Folder Y”.

  The second user 102 selects a folder for acquiring content from the folder list displayed on the second client 12. Next, a content acquisition operation is performed on the folder (step 1006).

  In response to an operation in which the second user 102 uses the second client 12 to acquire content from the folder, the server 3 reads a table that defines the folder characteristics of the designated folder, and performs the second usage. The table is searched using the user name of the user 102 as a keyword (step 1007), and a usage rule corresponding to the second user 102 is acquired (step 1008).

  For example, assuming that the designated folder is “folder X” and the stored user name is “B”, in the example of FIG. 3, the corresponding usage rule is “usage rule II”.

  Then, the server 3 reads the designated content 7 (step 1009) and embeds the usage rule acquired earlier. Next, the second client 12 acquires the content in which the usage rule is embedded from the server 3.

  In the previous example, since the usage rule is “Usage Rule II”, according to FIG. 4, the “restriction regarding content” is “viewing authority” and “printing authority”. Embed usage restrictions that allow "authorization" and "printing authority" and prohibit "transcription authority" and "editing authority".

  In order to realize “browsing authority”, the server 3 extracts the public key from the digital certificate of the second user 102 and encrypts the content by using this public key. It is also possible to use a common key instead of the public key. In this case, the server 3 uses a session for encrypted communication between the second client 12 and the server 3 to provide a secret value (= common key value) owned by the second user 102 to the second client 12. ). Next, the second user 102 inputs a secret value in response to a request from the server 3. Then, the second client 12 returns the secret value to the server 3 in response to the input of the secret value by the second user 102. Next, the server 3 uses the secret value to encrypt the content by a common key encryption method. Then, the second client 12 downloads content from the server 3 (step 1010).

  When the content registration is notified by e-mail, the second user 102 who has received the e-mail clicks on the URL portion to perform the login operation (step 1005), folder selection and content acquisition. The operation (step 1006) and the content download operation (step 1010) are automatically executed, and the user's operation can be simplified.

(Use of content)
When using the content, the second user 102 inserts the token 62 into the second client 12 and activates the browsing software 201.

  In response to an operation in which the second user 102 browses the content, the second client 12 (browsing software 201) extracts the secret key owned by the second user 102 from the token 62, and uses this secret key. Use it to decrypt the content and make it viewable. Furthermore, the usage rule included in the content is confirmed, and operation restriction according to the usage rule is given to the browsing software 201. That is, the second client 12 controls the use of content for the second user 102 in accordance with the usage rules.

  When the content is encrypted using the common key, the second user 102 inputs the secret value that has been transmitted to the server 3 to the browsing software 201 first. Then, the second client 12 decrypts the content with this secret value. As a result, the second user 102 can browse the content.

  In the above example, since “printing authority” is permitted and “transcription authority” and “editing authority” are prohibited, only the printing operation is valid and the posting and editing operations are invalid in the viewing software 201. Control is applied.

  On the other hand, even if a third party user obtains the content downloaded by the second user 102 by some means, the encrypted content is decrypted if there is no token 62 held by the second user 102. Cannot be viewed.

  Examples of the browsing software 201 include Adobe Acrobat from Adobe Systems and DocuWorks from Fuji Xerox. For example, when using Adobe Acrobat, the PDF format is used as a content format for use control. The process of converting the original content into the PDF format (in the case of Acrobat) or the DocuWorks format is performed by the first client 11 or the server 3 when uploading the content in step 1003, or on the server 3. The server 3 executes as part of the process.

  In addition, when the second user 102 leaves the company or the duties are changed, the second user 102 is prevented from browsing contents already downloaded and held, or the usage rules are changed. You may want to In this case, restriction information for specifying the expiration date of the content is included in the usage rule. Then, when the second user 102 browses the content using the browsing software 201, the second client 12 acquires the current time information, compares it with the expiration date of the usage rule included in the content, If the expiration date of the content has passed, the content is automatically deleted. By operating with this expiration date shortened, it is possible to cope with changes in usage rules in a short period of time.

  The same mechanism can be realized by using version information of the usage rules instead of the expiration date of the content. That is, content version information is included in the usage rule. Then, in a state where the second client 12 is connected to the server 3, the second client periodically acquires the latest version information of the usage rules applied to the content from the server 3 and is included in the content. If the version of the usage rule included in the content is older than the version information of the usage rule, the content is automatically deleted.

  After the content is deleted, if the second user 102 needs more content, the content needs to be downloaded again. At this time, since the latest usage rule is applied to the content by the server 3, the operation restriction is applied to the downloaded content according to the latest usage rule.

  In some cases, the second user 102 may want to prevent the second user 102 from newly downloading content due to leaving the company or changing duties. In this case, the name of the second user 102 is deleted from the folder characteristics, or the token 62 held by the second user 102 is collected. Further, access to the server 3 may be prohibited by using a mechanism (CRL: Certificate Revocation List) for revoking the digital certificate written in the token 62.

It is a block diagram which shows schematic structure of the content delivery utilization control system which concerns on embodiment of this invention. It is a figure for demonstrating operation | movement of the system of FIG. It is a figure which shows an example of the table which prescribes | regulates a folder characteristic. It is a figure which shows an example of the table which defined the usage rule.

Explanation of symbols

101 to 10N users 11 to 1N client 2 network 3 server 4 usage rules 5 administrator device 7 contents 61 and 62 token 201 browsing software

Claims (11)

In response to the operation of the first user, the first client registers the content in the server;
In response to an operation in which a second user obtains the content from the server using a second client, the server embeds a usage rule registered in advance in the server in the content;
The second client obtaining the content with the usage rule embedded from the server;
And a step of controlling the use of the content by the second client in accordance with the use rule, with respect to the second user.   Each of the first and second clients performs mutual authentication with the server prior to communication with the server, exchanges an encryption key, and uses the encryption key when communicating with the server. 2. The content distribution use control method according to claim 1, wherein a session for encrypted communication is established. For mutual authentication between the first and second clients and the server, a digital certificate that guarantees the validity of the public key owned by the first and second users, and the server Using public key cryptography with a digital certificate that guarantees the validity of the public key,
In a process in which the second client establishes a session for cryptographic communication with the server, the server obtains a digital certificate of the second user;
The server encrypts the content using the public key of the second user included in the digital certificate of the second user;
In response to an operation in which the second user browses the content, the second client further includes the step of decrypting the content with a secret key owned by the second user. 3. The content distribution use control method according to claim 2, wherein The server requesting a secret value owned by the second user from the second client using a session for cryptographic communication between the second client and the server;
The second client responding to the input of the secret value by the second user and replying the secret value to the server;
The server encrypts the content using a secret key using a secret key encryption method;
3. The method according to claim 2, further comprising: a step in which the second client decrypts the content with the secret value in response to an operation in which the second user browses the content. Content distribution usage control method. A plurality of folders are registered in the server, and each server has a table describing folder characteristics,
In the table, a user name of a user who is permitted to use the folder and a usage rule that the user is permitted to use are described.
In response to an operation in which the second user acquires the content from the folder using the second client, the server uses the user name of the second user as a keyword to store the table. Searching and obtaining corresponding usage rules;
The content distribution usage control method according to claim 1, further comprising the step of embedding the usage rule in the content. In the process of establishing a session for cryptographic communication between the first and second clients and the server, the server obtains digital certificates of the first and second users, respectively.
The server retrieving the user names of the first and second users from the digital certificates of the first and second users, respectively;
A list in which the server searches the table based on the user names of the first and second users and displays only the folders that the first and second users are permitted to use. The content distribution use control method according to claim 1, further comprising the steps of: generating and transmitting to the first and second clients, respectively.   In response to the content being registered in the folder from the first client, the server sends an email indicating that the content has been registered to all users' clients listed in the table. The content distribution usage control method according to claim 1, further comprising a step of notifying.   As the notification contents of the e-mail, the name of the first user, the name of the folder in which the content is registered, the name of the content, an outline of the content, and the storage location of the content are described. The content distribution use control method according to claim 7, wherein: Use the PDF (Portable Document Format) format as the content format to control usage,
2. The content distribution usage control method according to claim 1, wherein the first client converts original content into a PDF format. The usage rule includes restriction information that specifies an expiration date of the content,
The second client further includes a step of deleting the content if the expiration date of the content has passed when the second client controls the use of the content to the second user according to the usage rule. The content distribution use control method according to claim 1, wherein: The usage rule includes version information of the usage rule,
When the second client controls the use of the content for the second user according to the usage rule, the second client obtains the latest version information of the usage rule applied to the content from the server. The content distribution according to claim 1, further comprising a step of deleting the content when the version information of the usage rule included in the content is old as compared with the version information of the usage rule included in the content. Usage control method.

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