JP2011133991A - Confidential data protection system, confidential data protection method, and confidential data protection program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively suppress the leakage of confidential information included in document data. <P>SOLUTION: A confidential data protection device 10 includes: an different system linkage means 11 for monitoring a document data processing content in a different system 100; a conversion means 13 for acquiring document data and converting confidential data in the document data into cryptic character data based on a confidential data dictionary when document data storage processing is performed; and a restoration means 14 for converting the cryptic character data into the confidential data to restore them according to the authority of a viewer when a document data viewing request for the document data is detected. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a system for protecting confidential information by concealing confidential information included in a file.

  Individuals such as the company name, address, contact information, person in charge, transaction information, system name, etc. included in this file data when saving the created file data or when sending and receiving file data via the network Information (customer information), information such as product names, etc., or information that you want to prevent leakage (information to be replaced) into other characters or symbols, such as “** Corporation” or “XX System” A technology for concealing (declining) by replacement, and a system for countermeasures against information leakage that encrypts the file itself are used.

  However, many of the information leakage countermeasures such as replacement of the information to be replaced as described above and encryption of a data file including the information to be replaced are left to the user's operation, so the information to be replaced is forgotten. In other cases, for example, the user forgets to encrypt the file, and this may cause inconvenience that the replacement target information leaks along with the file data on the network.

In addition, the above-mentioned information leakage countermeasure system makes fine settings related to the disclosure of confidential information, such as disclosing a specific character string or data included in a document only to a specific user set in advance. Can not do it.
For this reason, when it is desired to select data to be disclosed for each user, it is necessary to create a plurality of files in which the confidential information is processed according to each user.

Furthermore, with respect to the data that has been subjected to the script processing, the authorized user who has performed the script processing of the confidential information needs to store and manage the confidential data before the script processing.
However, when the name before the conversion of the data that has been subjected to the character processing (character conversion) is required, for example, when the data has been stored for a long time, the user stores the corresponding confidential data. However, it is difficult to restore the original data to the original confidential information.

  As related information for this, for each file to be converted, a replacement map indicating the correspondence between the replacement target character and the replaced character is created, and this replacement map is stored in association with the file name, and stored in the replacement map. A system that suppresses leakage of information by performing replacement processing of characters to be replaced is disclosed (Patent Document 1).

In addition, as a related technique, a system is disclosed in which the contents of a registered file in which characters after substitution (abbreviated characters) in a file are marked are stored in a database (Patent Document 2).
Further, as a related technique, a method of setting a confidential processing (digital watermark) procedure group in a remote server and preventing the user from analyzing the content of the confidential processing is disclosed (Patent Document 3).

Japanese Patent Application No. 2007-156861 Japanese Patent Application No. 2004-116555 Japanese Patent No. 3633488

However, in the above-mentioned Patent Document 1, since the replacement information is stored in the apparatus for each file, there is a disadvantage that the storage capacity of the target file increases as the target file increases.
Moreover, in the said patent document 1, it is the structure by which the substitution file which shows the correspondence of the document file with which the character data (character after substitution) was embedded, the character for substitution, and the character after substitution is stored in the apparatus. As a result, both the document file and the replacement map may leak.

[Object of invention]
The present invention provides a confidential data protection system, a confidential data protection method, and a confidential data protection program capable of improving the disadvantages of the related technology and effectively suppressing leakage of confidential information contained in document data. For that purpose.

  In order to achieve the above object, a confidential data protection system according to the present invention is a document information management apparatus that performs processing for storing document data including confidential data and presents the document data in response to a browsing request from a viewer. And a confidential data protection system that converts the confidential data included in the document data into preset subscript data, wherein the data converter includes the confidential data and the confidential data. A confidential data dictionary holding unit for storing a confidential data dictionary indicating a correspondence relationship with the abbreviated character data set corresponding to the document data, and a storage execution detecting unit for detecting an operation start of the document data storing process in the document information management apparatus And when the start of the operation of the storage process is detected, the document data is acquired and the document data is acquired prior to the execution of the storage process. It has taken a configuration in which a data replacement execution unit to replace the sensitive data in data into the asterisk data based on the secret data dictionary.

  In addition, the confidential data protection method according to the present invention includes a document information management device that performs processing for storing document data including confidential data, and correspondence between the confidential data and abbreviated data set in advance corresponding to the confidential data. A confidential data protection system comprising a data conversion apparatus that holds confidential data indicating a relationship, and a confidential data protection method for replacing the confidential data, the processing content of the document information management apparatus for the document data When the document data storage process is detected, the document data in the document information management device is replaced with hidden data based on the confidential data dictionary, and the document data Whether or not to restore and convert the character data to confidential data according to the authority of the viewer when a browsing request from the viewer is detected When the restoration conversion is permitted, the baffle data is restored and converted into confidential data based on the confidential data dictionary, and the document data in which the confidential data is restored is presented to the viewer. Yes.

  In addition, the confidential data protection program according to the present invention provides a correspondence between a document information management apparatus that performs processing for storing document data including confidential data, and correspondence between the confidential data and abbreviated data set in advance corresponding to the confidential data. A confidential data protection system comprising a data conversion device that holds confidential data indicating a relationship, wherein the confidential data protection program replaces the confidential data, and the processing content of the document information management device for the document data is A storage process detection function for monitoring and detecting that the storage process of the document data is started, and confidential data for replacing the confidential data of the document data in the document information management apparatus with the hidden data based on the confidential data dictionary When a browsing function is detected from the viewer with respect to the replacement function and the document data, A restoration conversion determination function for determining whether or not character data is restored and converted to confidential data, and a restoration conversion execution for restoring and converting the character data to confidential data based on the confidential data dictionary when the restoration conversion is allowed The function is executed by a computer provided in the data converter.

  Since the present invention is configured and functions as described above, according to this, the means for detecting the operation start of the document data saving process in the document information management apparatus installed outside, and the document data saving process are detected. In this case, prior to the execution of the storage process, the document data is provided with a means for replacing the confidential data in the document data with the hidden data based on the confidential data dictionary. It is possible to provide a confidential data protection system, a confidential data protection method, and a confidential data protection program capable of effectively suppressing leakage of confidential information contained therein.

1 is a schematic block diagram illustrating an embodiment of a confidential data protection system according to the present invention. It is explanatory drawing which shows an example of the authority table stored in the authority database in the confidential data protection system disclosed in FIG. It is explanatory drawing which shows an example of the conversion authority table stored in the authority database in the confidential data protection system disclosed in FIG. It is explanatory drawing which shows an example of the conversion table memorize | stored in the confidential data dictionary memory | storage part as a confidential data dictionary in the confidential data protection system disclosed in FIG. It is explanatory drawing which shows an example of the conversion table memorize | stored in the confidential data dictionary memory | storage part as a confidential data dictionary in the confidential data protection system disclosed in FIG. It is explanatory drawing which shows an example of the conversion table memorize | stored in the confidential data dictionary memory | storage part as a confidential data dictionary in the confidential data protection system disclosed in FIG. It is a flowchart which shows the operation | movement process step of the conversion means in the confidential data protection system disclosed in FIG. It is explanatory drawing which shows the encryption system of the conversion data in the confidential data protection system disclosed in FIG. It is a flowchart which shows the operation | movement process step of the decompression | restoration means in the confidential data protection system disclosed in FIG. It is explanatory drawing which shows an example of the individual document conversion authority table memorize | stored in the authority database in the confidential data protection system disclosed in FIG. FIG. 3 is an explanatory diagram showing an example of a conversion table stored in an authority database in the confidential data protection system disclosed in FIG. 1 and having a conversion counter set therein.

[Embodiment]
Next, the basic configuration content of the embodiment of the present invention will be described.

  As shown in FIG. 1, the confidential data protection system according to the present embodiment stores and manages a document file including document information (document data), for example, a mail server (mail system) or a document information database (document management system). The other system (document information management apparatus) 100 is connected to the other system 100 via a communication line, and processing operations performed on the document information in the other system 100 are monitored. A configuration including a confidential data protection device (confidential data conversion device) 10 that converts confidential data included in the document information before the storage processing is performed when the storage processing of the document information is performed in 100. It has become.

  The confidential data protection device 10 monitors a processing operation performed on the document information in the other system 100 and transmits / receives a document file to / from the other system 100, and the other system cooperation unit 11 The document file acquired via the data input unit 12 that distributes the document file to the conversion unit 13 or the restoration unit 14 based on the document content, and is included in the document file based on a preset confidential data dictionary (stored in the confidential data dictionary storage unit 21). The converted data (character string) is converted into another preset character string (abbreviated character data), and the data converted by the data converting means 13 included in the document file (abbreviated character data) Data restoring means 14 for performing processing to restore the original confidential data, and the converted or restored document file to another system Having a data output means 15 to be output to the linkage means 11.

The confidential data protection device 10 also includes an authority database (DB) 31 that holds browsing authority information indicating authority to permit browsing of confidential data, confidential data (characters to be replaced) included in a document file, and the confidential data. A confidential data dictionary storage unit 21 for storing a confidential data dictionary which is a data conversion map indicating a correspondence relationship with the abbreviated character data (character string after replacement) set in correspondence with the authority table, and an authority table stored in the authority DB 31 The configuration includes an authority DB creation means 30 for registering and updating information, and a confidential data dictionary creating means 20 for registering and updating information in the confidential data dictionary of the confidential data dictionary storage unit 21.
Note that the confidential data dictionary creation means 20 and the authority DB creation means 30 have a function of accepting new registration data input or update by an operator (user) of the confidential data protection device 10.

  The confidential data protection device 10 may be a functional system (a confidential data conversion system) realized by execution of a preset program. In this case, when an execution request (save process request) for storing a document (document file) in another system 100 is detected, the confidential data conversion system (functional operation in the confidential data protection device 10) is an API or the like. It is assumed that it is executed by being called by.

  Further, when the confidential data protection device 10 is a functional system (a confidential data conversion system) realized by executing a preset program, a process of opening a document (document file) in another system 100 is performed. When an execution request (file open request) is detected, the confidential data conversion system (functional operation in the confidential data protection device 10) is called by an API or the like and executed.

The confidential data dictionary stored in the confidential data dictionary storage unit 21 includes a conversion authority table (FIG. 3) and conversion tables (FIGS. 4 to 6).
Here, as shown in FIG. 3, the conversion authority table classifies confidential data such as personal information into specific attribute units (company, address, contact information, etc.), and allows disclosure to the user for each attribute. It is assumed that the authority level is set. In addition, an address of a conversion table storing information for converting confidential data is set for each attribute.

  Also, in the conversion table, as shown in FIGS. 4 to 6, baffle data corresponding to each confidential data is registered as table data (data conversion map).

It is assumed that unique attribute data is set in the confidential data (return data) registered in the conversion table and the corresponding character data when the confidential data is registered in the dictionary.
For example, the attribute “company” is set as an attribute in “Asahi Shoji Co., Ltd.” as confidential data. As a result, “Asahi Shoji Co., Ltd.” is registered in the attribute “enterprise” in the conversion table as baffle data “enterprise 1”.

The authority DB 31 holds a preset authority table.
In the authority table, as shown in FIG. 2, a user identifier for identifying a browsing user or the like by a user ID and a level (authority level) permitting disclosure of confidential data are registered.
Based on this authority level, it is determined whether or not the conversion table for each attribute of the confidential data dictionary 21 can be referred to.

The other system linking unit 11 is configured to detect a document (document file) storage process execution request (save process request) in another system (document information management apparatus) 100 such as a mail system or a document management system. Prior to these processes being performed, document data is acquired and this document is passed to the data input means 12.
At this time, in another system 100, it is assumed that the document file saving process is set to the execution pending state.

The other system cooperation unit 11 acquires the document file when the process (viewing process) for opening the document (document file) is detected in the other system 100 and passes the document to the data input unit 12. . Further, it is assumed that this document file includes an identifier (user identifier) set corresponding to the user who is going to perform the process of opening this document file.
At this time, in another system 100, the process of opening the document file is set to the execution pending state.

The other system 100 may be a thin client system that does not have a secondary storage device such as an HDD for storing and storing document files.
In this case, when the other system 100 needs to save the document file, the other system 100 transmits a message requesting to save the document file and the document file to be saved to the other system cooperation unit 11, and the other system cooperation unit 11. Suppose that the following file processing is incorporated into the sent document file and the document file is saved.

When the other system 100 is a thin client system, when the other system 100 opens the document file, a message requesting a desired document file is transmitted to the confidential data protection device 10.
Further, it is assumed that the other system cooperation unit 11 performs processing for restoring the following abbreviation data for the received message and transmits the document file.

Further, the other system 100 has a restored document file display function for displaying the restored document file sent from the system cooperation unit 11 on the output screen.
If the other system 100 is a thin client, the contents of the displayed character file cannot be saved, and are deleted after being browsed and displayed.

Further, when the other system 100 saves the restored document file, the secret data protection apparatus 10 again obtains it, and the secret data is processed to be processed.
As a result, the restored document file including the restored confidential data is suppressed from being stored in the other system 100, and thus leakage of the confidential data can be effectively suppressed.

  The conversion means 13 extracts the confidential data table registered in the confidential data dictionary 21 when the document data acquired by the other system cooperation means 11 is input from the other system 100 (conversion table acquisition function).

  As described above, the confidential data dictionary storage unit 21 associates confidential data (confidential information) set in advance as the confidential data dictionary with concealment data that is conversion data set corresponding thereto. A confidential data table (conversion table: FIG. 4 to FIG. 6) to be stored and a conversion authority table (FIG. 3) in which authority levels capable of restoring the converted data (abbreviated data) based on the conversion table are stored. ing.

The confidential data table is set corresponding to the attribute defined in the conversion authority table. Here, the company conversion table set in correspondence with the attribute “company” (FIG. 4), the address conversion table set in correspondence with the attribute “address” (FIG. 5), and the attribute “contact” are set. It is assumed that the set contact conversion table (FIG. 6) is stored in advance in the confidential data dictionary storage unit 21.
In addition, the conversion authority table defines an authority level for restoring the character data for each conversion table.

  Further, since the most important data in the confidential data protection device 10 is stored in the confidential data dictionary storage unit 21, the confidential data table (FIGS. 4 to 4) is used to prevent the data contents from being easily read. 6) Each is encrypted and stored.

  Note that the conversion table (secret data table) may be set with a counter item indicating the number of times the confidential data has been converted as shown in FIG. Here, an example is shown in which a conversion counter item is installed in the company conversion table (FIG. 4).

In this case, the conversion means 13 adds the value of the counter every time the confidential data is converted into the hidden data.
This makes it easy to maintain the contents of the confidential data dictionary, such as deleting the confidential data when the data registered as confidential data has not been used for a certain period of time (that is, when the counter value is 0). It is possible to do. This also makes it possible to increase the efficiency of the search processing speed for confidential data in the document file.

  The conversion means 13 has a confidential data search function for searching confidential data in document data based on the extracted confidential data table. Here, the conversion means 13 determines whether or not confidential data included in the confidential data table is included in the document data (sensitive data content determination function).

  Here, when the confidential data is found, the conversion means 13 obtains the acronym data set corresponding to the confidential data from the extracted confidential data table and replaces the confidential data with the acronym data. (Data conversion function).

  Furthermore, the conversion means 13 inserts the identifiers into the document file before and after the character data by inserting identifiers that are not normally used when incorporating the character data into the document file, that is, when replacing the confidential data with the character data. It has a special character string embedding function for enclosing data and incorporating it into document data.

  Further, the conversion means 13 changes the character color of the substitution data input by replacement, converts the font of the alphabet data to another font, or converts the background color of the alphabet data to another color. Accordingly, a setting may be made in which character attributes that are easily distinguishable from other character strings in the document file (document data) are given to the hidden character data.

  Specifically, when the character string set as the identifier is “/? & *” And “* &? /”, The conversion means 13 replaces the confidential data “Sunset Shoji Co., Ltd.”. Becomes “/? & *” Company 2 “* &? /”. In addition, italic / bold attributes may be set for the character data “company 2”.

  In this way, by incorporating a special character string into a document file, it is possible to quickly find a target portion for data conversion when restoring the hidden character data in the document file to confidential data.

  As described above, since the confidential data (table) stored in the confidential data dictionary storage unit 21 has been previously encrypted, in this case, the conversion means 13 decrypts the confidential data table when reading it. Processing (decryption processing) shall be performed (confidential data decryption function).

For example, as shown in FIG. 8, the decryption process is performed by decrypting the decryption key 1 with the preset decryption key 2 and decrypting the confidential data (table) with the decryption key 1 and then the characters in the document file. Compare with column.
It should be noted that here, if there is simply one decryption key, a certain level of security can be maintained, but if the existence (storage location) of the decryption key 1 is known, the security is weakened. It is assumed that double security is included.

  Further, when the conversion means 13 confirms that all the confidential data in the document file has been replaced with the abbreviated data, the data output means 15 converts the document file in which the abbreviated data is set to the other system cooperation means. 11 to the other system 100 (converted document file transmission function).

Here, the conversion unit 13 may be set to transmit information indicating which portion (part) in the document file has been replaced with confidential data as confidential data, attached to the converted document file. .
Thereby, it becomes possible to more accurately determine whether or not the confidential data is appropriately replaced with the character data. For example, if data that the document creator wanted to handle as confidential data has not been registered in the confidential data dictionary and thus has not been converted into hidden data, this can be quickly determined.

  In this case, new confidential data replacement processing can be performed on the document file by newly registering the confidential data in the confidential data dictionary.

  The restoring means 14 searches for a special character string set in advance in the document file, and displays a special character string (for example, “/? & * Company 2 * &? /”) Or “company 2” indicating that the character data is written data. "Has a special character string determination function for determining whether or not information in italics is included in the document file.

  Here, when the special character string is included, the restoration unit 14 acquires the authority table (FIG. 2) indicating the authority level of the user of the other system 100 from the authority DB 31 and from the confidential data dictionary 21, the attribute ( Whether there is a table acquisition function that acquires a conversion authority table (FIG. 3) that defines the authority level that can be disclosed for each company, address, contact, etc., and an attribute conversion table that can be disclosed at the authority level of the user And a user authority level determination function for determining whether or not.

  When there is an attribute conversion table that can be disclosed at the authority level of the user, the restoration unit 14 acquires the attribute conversion table (all or a part of FIGS. 4 to 6) from the confidential data dictionary storage unit 21. , Check the attribute embedded in the special character string, search for the data corresponding to the cryptic data based on the conversion table of that attribute, and if there is such data, replace it with confidential data It has a data recovery function.

  Here, for example, since an attribute is embedded at the beginning of the special character string, it is only necessary to search the conversion table for that attribute. Thereby, the efficiency of the processing time concerning the restoration process of the restoration means 14 is achieved.

  In addition, since the confidential data stored in the confidential data dictionary is encrypted, the restoring unit 14 has a confidential data decrypting processing function for performing a decrypting process when performing reading.

  When the data output means 15 detects that the restoration means 14 has confirmed that all the confidential data in the document file has been replaced with the character data, the data output means 15 sends the restored document file via the other system cooperation means 11. A restored document file transmission function for transmission to another system 100 is provided.

  In the present embodiment, it is assumed that the conversion authority table of the confidential data dictionary is used for user sharing. However, the conversion authority table corresponding to each document file may be set. .

The individual document conversion authority table stored in the confidential data dictionary storage unit 21 is shown in FIG.
Here, a conversion authority table including items such as an attribute, an authority level, and a conversion table address is defined corresponding to each unique document number (document number # T123456, document number # T987654) set in the document file. Yes.
The items in each table other than the document number are the same as the configuration shown in the common conversion authority table in FIG.

When receiving a document file including confidential data, the conversion means 13 first determines whether there is an individual document conversion authority table corresponding to the document file (individual document), and an individual document that matches the document number of the individual document. If there is a conversion authority table, data is loaded from the corresponding individual document conversion authority table, and based on this, the process of converting confidential data in the document file into baffled data is performed.
This makes it possible to set the contents of conversion of confidential data for each individual document, and to view confidential data before the document file is viewed (that is, at the stage of saving the document file (individual document)). It is possible to perform conversion to the written data according to the authority level of the person.

As described above, in this embodiment, personal information (customer information) such as name, address, office, company name, contact information, person in charge, transaction content information, and system name) and confidential data such as product name are included. When a document file (document data) is stored or when a document file in which the above confidential data is converted into abbreviated data is opened for browsing, the document file is automatically created without being aware of the document creator. A system for preventing leakage of confidential data is realized by replacing the confidential data with other data (buffy data) based on the information of the confidential data (the confidential data table) acquired and registered in advance.
Also, when a document that has been replaced with other data is viewed, the confidential data is disclosed by performing a process of restoring a part (or all) of the confidential data according to the authority of the browsing user. be able to.

[Description of Operation of Embodiment]
Next, an outline of the operation of this embodiment will be described.
First, the data conversion apparatus monitors the processing content of the document data in the document information management apparatus and detects that the storage process of the document data (processing target document data) in the document information management apparatus is started (storage process). In the detection step), the document data is acquired and the confidential data included in the document data is replaced with the character data based on the preset confidential data dictionary (the confidential data replacement step).
Next, when a browsing request for document data in the document information management apparatus is detected, the data conversion apparatus determines whether or not to restore and convert the character data included in the document data into confidential data before replacement. Based on the security data (restoration authority judgment process), when restoration conversion is allowed, the hidden data in the document data is restored to confidential data based on the confidential data dictionary (restoration conversion process), and the hidden data is converted to confidential data. The restored document data is transmitted to the document information management apparatus.
Here, the above-described storage processing detection step, confidential data replacement step, restoration authority determination step, and restoration conversion step may be configured such that the execution contents are programmed and executed by a computer.

  Next, the operation of the conversion means 13 for converting the confidential data into the hidden data in the confidential data protection device 10 of the present embodiment will be described based on the flowchart of FIG.

  The data input means 12 inputs the document data acquired from the other system cooperation means 11 to the conversion means 13 (data input: step S10). Here, the data input means 12 passes this document data to the conversion means 13 when the other system cooperation means 11 detects the saving process and acquires the document data.

  The conversion means 13 receives the input document data, and repeats the operations of steps S12 and S13 (steps S14 to S17) shown below (step S11).

  When the document data sent from the other system 100 is input, the conversion unit 13 first extracts the confidential data table registered in the confidential data dictionary 21 (step S12).

  The confidential data dictionary storage unit 21 stores confidential data (confidential information) set in advance as a confidential data dictionary in association with concealment data that is conversion data set in correspondence with the confidential data. It is assumed that a table (conversion table: FIGS. 4 to 6) and a conversion authority table (FIG. 3) defining authority levels that can restore the converted data (buffy data) based on the conversion table are stored. .

The confidential data table is set corresponding to the attribute defined in the conversion authority table. Here, the company conversion table set in correspondence with the attribute “company” (FIG. 4), the address conversion table set in correspondence with the attribute “address” (FIG. 5), and the attribute “contact” are set. It is assumed that the set contact conversion table (FIG. 6) is stored in advance in the confidential data dictionary storage unit 21.
In addition, the conversion authority table defines an authority level for restoring the character data for each conversion table.

  Next, based on the extracted confidential data table, the conversion unit 13 repeatedly executes the operations from Steps S14 to S17 to the end of the document file (document data) (Step S13).

That is, the conversion means 13 searches for confidential data in the document data based on the extracted confidential data table (step S14).
Here, the conversion means 13 determines whether or not confidential data included in the confidential data table is included in the document data (step S15).

  Here, when confidential data is found (present: step S15), the conversion means 13 acquires the abbreviated character data set corresponding to the found confidential data based on the confidential data table (step S16: the affixed character data). In addition, a process for replacing the confidential data is performed by using the character data (applying character data: step S17).

  If the confidential data is not found (none: step S15), the conversion unit 13 searches the document data for other confidential data included in the confidential data table (step S14).

  Since the most important data in the confidential data protection device 10 is stored in the confidential data dictionary storage unit 21, the confidential data table (FIG. 4 to FIG. 4) is used to prevent the data contents from being easily read. 6) Each is encrypted and stored.

  For example, if the confidential data extracted from the document file as the search result is confidential data included in the “company” conversion table of FIG. 4, for example, the conversion means 13 uses the concealment registered corresponding to the confidential data. Read data.

Specifically, as shown in FIG. 4, when “Sunset Trading Co., Ltd.” in the document data corresponds to the confidential data, the conversion means 13 reads “Company 2” as the baffle data (obtaining bull character data: step S16).
Next, the conversion means 13 performs a process of replacing the confidential data “Sunset Trading Co., Ltd.” in the document data extracted by the search with the affixed data “Company 2” (applied data applied: step S17).

Note that the conversion means 13 inserts the identifier of a character string that is not normally used when embedding the script data into the document file, that is, replaces the confidential data with the script data, by inserting identifiers before and after the script data. The setting may be such that the data is enclosed and incorporated in the document data.
Further, the conversion means 13 changes the character color of the substitution data input by replacement, converts the font of the alphabet data to another font, or converts the background color of the alphabet data to another color. Accordingly, a setting may be made in which character attributes that are easily distinguishable from other character strings in the document file (document data) are given to the hidden character data.

  Specifically, when the character strings set as identifiers are “/? & *” And “* &? /”, The character string to be incorporated instead of the confidential data “Sunset Trading Co., Ltd.” is “/? & * ”Company 2“ * &? / ”. In addition, italic / bold attributes may be set for the character data “company 2”.

  In this way, by incorporating a special character string into a document file, it is possible to quickly find a target portion for data conversion when restoring the hidden character data in the document file to confidential data.

  As described above, since the confidential data (table) stored in the confidential data dictionary storage unit 21 has been previously encrypted, in this case, the conversion means 13 decrypts the confidential data table when reading it. Processing shall be performed.

For example, as shown in FIG. 8, the decryption process is performed by decrypting the decryption key 1 with the preset decryption key 2 and decrypting the confidential data (table) with the decryption key 1 and then the characters in the document file. Compare with column.
It should be noted that here, if there is simply one decryption key, a certain level of security can be maintained, but if the existence (storage location) of the decryption key 1 is known, the security is weakened. It is assumed that double security is included.

  When the conversion means 13 confirms that all the confidential data in the document file has been replaced with the abbreviated data, the data output means 15 converts the document file in which the abbreviated data is set to the other system cooperation means 11. To the other system 100 (step S18).

Note that the setting may be such that information indicating which part (portion) in the document file is replaced with the hidden data as confidential data is attached to the document file and transmitted.
Thereby, it becomes possible to more accurately determine whether or not the confidential data is appropriately replaced with the character data. For example, if data that the document creator wanted to handle as confidential data has not been registered in the confidential data dictionary and thus has not been converted into hidden data, this can be quickly determined.
In this case, new confidential data replacement processing can be performed on the document file by newly registering the confidential data in the confidential data dictionary.

  Next, the operation steps of the restoring means 14 for restoring the original data set in the document file to the original confidential data will be described with reference to the flowchart of FIG.

First, the data input means 12 acquires a document file that has been subjected to the script processing via the other system cooperation means 11 and inputs it to the restoration means 14 (data input: step S20).
Here, the restoring means 14 searches for a special character string set in advance in the document file (step S21), and a special character string (eg, “/? & * Company 2 * &? It is determined whether or not “/” or italics are included (step S22).

  Here, when the special character string is not included, the restoring unit 14 determines that the hidden character data is not included, and ends the confidential data restoring process.

On the other hand, when the special character string is included, the restoration unit 14 acquires an authority table (FIG. 2) indicating the authority level of the user of the other system 100 from the authority DB 31 (step S23).
In the authority table, as shown in FIG. 2, an identifier (user identifier) for identifying a user and an authority level thereof are set in advance.
Next, the restoring means 14 acquires a conversion authority table (FIG. 3) defining authority levels that can be disclosed for each attribute (company, address, contact address, etc.) from the confidential data dictionary 21 (step S24).

At this time, the restoring means 14 determines whether or not there is an attribute conversion table that can be disclosed at the authority level of the user (determination: step S25).
Here, it is assumed that the restoring unit 14 repeats the operations in steps S27 to S32 until the end of the document file (document data) (step S27).

When there is an attribute conversion table that can be disclosed at the authority level of the user (Yes: Step S28), the restoration means 14 saves the attribute conversion table (all or part of FIGS. 4 to 6) in the confidential data dictionary. Obtained from the unit 21 (step S29).
On the other hand, if there is no attribute conversion table that can be disclosed at the authority level of the user, a special character string is searched in the document data (step S32).

  Here, the restoration means 14 confirms the attribute embedded in the special character string (Yes: Step S30) and confirms it by searching for data corresponding to the character data based on the attribute conversion table. If there is, it is replaced with confidential data (step S31).

  Here, for example, when an attribute is embedded at the beginning of the special character string, the restoration unit 14 only needs to search the conversion table corresponding to the attribute. Thereby, the efficiency of the processing time concerning the restoration process of the restoration means 14 is achieved.

  Note that since the confidential data stored in the confidential data dictionary is encrypted, the restoration unit 14 needs to perform a decryption process (read function for the confidential data decryption).

  Next, when the restoration means 14 confirms that all the confidential data in the document file has been replaced with the hidden data (up to here: corresponding to step S26), the data output means 15 selects the restored document file. It transmits to the other system 100 via the other system cooperation means 11 (step S33).

At this time, the other system 100 displays the restored document file sent from the system cooperation unit 11 on the output screen.
If the other system 100 is a thin client, the contents of the displayed character file cannot be saved, and are deleted after being browsed and displayed.

Further, when the other system 100 saves the restored document file, the secret data protection apparatus 10 again obtains it, and the secret data is processed to be processed.
As a result, the restored document file including the restored confidential data is suppressed from being stored in the other system 100, and thus leakage of the confidential data can be effectively suppressed.

As described above, in the present embodiment, the confidential data included in a document can be changed depending on the level of the viewer, without the document creator and the viewer being aware of it. Detailed information leakage countermeasures can be set without creating a document.
Further, in the present invention, when a user saves a document in the system, the confidential information in the document is saved in a hidden form, and furthermore, the confidential information is collectively managed and the confidential information is encrypted. Security measures can be strengthened by taking countermeasures.

  The present invention can be applied to a system that conceals and protects confidential data included in document information shared via a network.

DESCRIPTION OF SYMBOLS 10 Confidential data protection apparatus 11 Other system cooperation means 12 Data input means 13 Conversion means 14 Restoration means 15 Data output means 20 Confidential data dictionary creation means 21 Confidential data dictionary storage part 30 Authority database (DB) creation means 31 Authority database (DB)
100 Other systems

Claims (10)

A document information management device that performs processing for storing document data including confidential data and presents the document data in response to a browsing request from a viewer, and a subscript that is set in advance for the confidential data included in the document data A confidential data protection system comprising a data conversion device for converting data,
The data converter is
A confidential data dictionary holding unit for storing a confidential data dictionary indicating a correspondence relationship between the confidential data and the written data set corresponding to the confidential data;
A storage execution detection unit that detects an operation start of the document data storage process in the document information management apparatus;
Data for acquiring the document data prior to the execution of the storage process when the start of the operation of the storage process is detected and replacing the confidential data in the document data with the concealed data based on the confidential data dictionary A confidential data protection system comprising a replacement execution unit. The confidential data protection system according to claim 1,
The data converter is
A browsing request detection unit that detects a browsing request from the viewer for the document data on which the storage process has been performed in the document information management device;
A confidential data protection system comprising: a restoration conversion means for restoring and converting the character data of the document data into confidential data according to the authority of the viewer when the browsing request is detected. The confidential data protection system according to claim 1,
The data converter is
A restoration conversion determination means for determining whether restoration conversion of confidential data included in the document data into confidential data is permitted based on the authority of the viewer when the browsing request is detected;
A restoration conversion data presentation unit for presenting the document data, which is restored and converted from the character data to the confidential data based on the confidential data dictionary, when the restoration conversion is permitted; A confidential data protection system. In the confidential data protection system according to claim 3,
The restoration conversion determination means includes
Authority information storage means for storing browsing authority information indicating a correspondence relationship between the viewer and the character data that is allowed to be restored and executed;
A confidential data protection system comprising: a restoration conversion determination execution unit that determines whether to execute the restoration conversion on the basis of the browsing authority information, for each character data. The confidential data protection system according to any one of claims 1 to 4,
The data replacement execution unit sets data type specifying information indicating the type of the confidential data in the script data and converts the data type specifying information into the secret data dictionary when the confidential data is converted into the script data. The data type setting function to be registered in
The confidential data protection system, wherein the restoration conversion data presentation unit includes a data type search function for searching the confidential data dictionary based on the data type identification information when performing the restoration conversion of the abbreviated character data. In the confidential data protection system according to any one of claims 2 to 4,
The confidential information protection system according to claim 1, wherein the document information management device includes a confidential data additional registration unit that additionally registers confidential data and hidden character data in the confidential data dictionary in response to a request from the viewer. In the confidential data protection system according to any one of claims 2 to 4,
The data converter is
A confidential data usage frequency calculation unit that calculates a reference frequency of each confidential data registered in the confidential data dictionary, and a confidential data dictionary that deletes the confidential data whose calculated reference frequency does not satisfy a preset reference frequency A confidential data protection system comprising an update unit. A document information management device for storing document data including confidential data, and a data conversion device for holding confidential data indicating a correspondence relationship between the confidential data and abbreviated data set in advance corresponding to the confidential data; A confidential data protection system comprising: a confidential data protection method for replacing the confidential data;
The processing contents of the document information management apparatus for the document data are monitored, and when it is detected that the storage process of the document data is started, the confidentiality of the document data in the document information management apparatus is determined based on the confidential data dictionary. A method for protecting confidential data, characterized in that data is replaced with hidden data. A document information management device for storing document data including confidential data, and a data conversion device for holding confidential data indicating a correspondence relationship between the confidential data and abbreviated data set in advance corresponding to the confidential data; A confidential data protection system comprising: a confidential data protection method for replacing the confidential data;
Monitoring the processing content of the document information management apparatus for the document data;
When it is detected that the storage process of the document data is started, the confidential data of the document data in the document information management device is replaced with the cryptic data based on the confidential data dictionary,
When a browsing request from a viewer for the document data is detected, it is determined whether or not to restore and convert the character data to confidential data according to the viewer's authority,
When the restoration conversion is allowed, the baffle data is restored and converted into confidential data based on the confidential data dictionary,
A method for protecting confidential data, wherein the document data on which the confidential data is restored is presented to the viewer. A document information management device for storing document data including confidential data, and a data conversion device for holding confidential data indicating a correspondence relationship between the confidential data and abbreviated data set in advance corresponding to the confidential data; A confidential data protection system comprising: a confidential data protection program for replacing the confidential data;
A storage process detection function for monitoring processing contents of the document information management apparatus for the document data and detecting that the storage process of the document data is started;
A confidential data replacement function that replaces confidential data of document data in the document information management device with prone data based on the confidential data dictionary;
A restoration authority determination function for determining whether or not to restore and convert the character data according to the authority of the viewer when a browsing request from the viewer for the document data is detected;
A confidential data protection program for causing a computer provided with the data conversion apparatus to execute a restoration conversion function for restoring and converting the character data into confidential data based on the confidential data dictionary when the restoration conversion is allowed .

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