JP2007334616A - Device, method and program for inputting/outputting data - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data inputting/outputting device and the like which dispense with decoding of the data every time in data reading request from a user. <P>SOLUTION: The data inputting/outputting device 1 comprises a user information storage unit 42 for storing user-specified information and an enciphered key corresponding to each other, a data writing unit 34 which reads the enciphered key of a user making a request from the user information storage unit when a data writing request is made, encodes control items by the read enciphered key, generates the enciphered data, and writes the data and the enciphered data in the data storage unit, and a data reading unit 34 which outputs the data read from the data storage unit for items other than the control items, and the decoded data generated by decoding the enciphered data by the enciphered key read from the user information storage unit for the control items to an output device, respectively. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to data input / output technology, and more particularly, to data input / output technology that can determine whether or not input data has been tampered with and can recover the tampered data.

If application data input by a user is recorded as it is in a storage device of a computer, there is a high risk that the data will be falsified or leaked. Therefore, various techniques for recording data in a safe form using an encryption technique or the like have been proposed.
Patent Document 1 describes such an information leakage prevention device. In this apparatus, the capsule generating means generates a capsule including encrypted application data obtained by encrypting application data with a key generated for each capsule, and an encrypted key obtained by encrypting the key with the user's public key. The capsule processing means decrypts the encryption key with the user's private key to obtain the decrypted second key, decrypts the encrypted application data with the decrypted second key, and passes it to the application program.

Japanese Patent Laid-Open No. 2004-3099

  However, in the above conventional technique, since the entire data is encrypted and recorded, there is a problem that the data has to be decrypted every time a data read request is received from the user.

  Accordingly, an object of the present invention is to provide a data input / output device or the like that does not require decryption of data each time a data read request is made by a user.

  A data input / output device according to the present invention includes a user information storage unit that stores user identification information for identifying a user and an encryption key defined for each user in association with each other, and data including a plurality of items. When there is a write request, the encryption key of the user who made this request is read from the user information storage unit, and the management item that is a part of the item is encrypted with the read encryption key to obtain the encrypted data. A data writing unit that generates and writes data and encrypted data to the data storage unit, and when there is a data read request, for items other than the management item, the data read from the data storage unit Reads the encryption key of the user who made the write request from the user information storage unit, and decrypts the encrypted data generated by decrypting the encrypted data with the read encryption key. It is and a, and a data read section for outputting to the output device (claims 1 to 4).

  According to the data input / output device, since items other than the management items are stored in the data storage unit without being encrypted, it is not necessary to decrypt the data every time a data read request is received from the user.

In the data input / output device, when there is a management item that does not match as a result of the comparison, and a data comparison unit that compares the data read from the data storage unit and the decrypted data with respect to the management item, A data restoration unit that updates the data stored in the unit with the decrypted data (claim 2).
In this way, the management item can be detected and recovered when the data stored without encryption is falsified.

In the data input / output device, for each management item, management item specification information different from the item specification information for specifying the item in the data is acquired, and the management item definition is associated with the item specification information and the management item specification information. You may make it provide the management item definition part written in a memory | storage part (Claim 3).
In this way, if the third party succeeds in obtaining the user's encryption key, the third party does not know the correspondence of the items between the input data and the encrypted data. However, the encrypted data cannot be falsified as intended.

In the data input / output device, the data includes user identification information for identifying the user as an item, and the data writing unit encrypts the user identification information with a predetermined system encryption key and stores it in the data storage unit. The writing / data comparison unit may search the management item definition storage unit using the user identification information decrypted by the system encryption key as a search key to obtain the encryption key.
In this way, unless the third party obtains the system encryption key, which user's encryption key should be used to decrypt the management item stored in the data storage unit. I can't know.

  The data input / output method of the present invention includes a user information storage step of storing user identification information for identifying a user in association with an encryption key defined for each user in a user information storage unit, When there is a request to write data containing the item, the encryption key of the user who made this request is read from the user information storage unit, and the management item that is part of the item is encrypted using the read encryption key. To generate encrypted data, write data and encrypted data to the data storage unit, and when there is a data read request, items other than the management items are read from the data storage unit Data for management items is generated by reading the encryption key of the user who made the write request from the user information storage unit and decrypting the encrypted data with the read encryption key. The decoded data includes a data reading step of outputting the respective output device (the claims 5 to 8).

  According to the data input / output method, since items other than the management items are stored in the data storage unit without being encrypted, it is not necessary to decrypt the data every time a data read request is received from the user.

In the data input / output method, when there is a data comparison step for comparing the data read from the data storage unit with the decoded data and a management item that does not match as a result of the comparison, the data storage is performed for the management item. A data recovery step of updating the data stored in the section with the decrypted data (claim 6).
In this way, the management item can be detected and recovered when the data stored without encryption is falsified.

In the data input / output method, prior to the data writing step, for each management item, management item specifying information different from item specifying information for specifying the item in the data is acquired, and the item specifying information, the management item specifying information, May be provided with a management item definition step of associating and writing to the management item definition storage unit (claim 7).
In this way, if the third party succeeds in obtaining the user's encryption key, the third party does not know the correspondence of the items between the input data and the encrypted data. However, the encrypted data cannot be falsified as intended.

In the data input / output method, the data includes user identification information for identifying the user as an item, and in the data writing step, the user identification information is encrypted with a predetermined system encryption key and stored in the data storage unit. In the writing and data comparison step, the encryption key may be acquired by searching the management item definition storage unit using the user identification information decrypted by the system encryption key as a search key.
In this way, unless the third party obtains the system encryption key, which user's encryption key should be used to decrypt the management item stored in the data storage unit. I can't know.

  The data input / output program of the present invention is a user information storage process for storing in a user information storage unit a user specifying information for specifying a user and an encryption key defined for each user in association with the computer. When there is a request for writing data including a plurality of items, the encryption key of the user who made the request is read from the user information storage unit, and the read encryption key is a part of the item Data storage processing for encrypting items to generate encrypted data, writing data and encrypted data to the data storage unit, and for items other than management items when there is a data read request For management items, the encryption key of the user who requested the write is read from the user information storage unit, and the encrypted data is read using the read encryption key. The decoded data generated by decoding the data, and data read processing of outputting the respective output device to the execution (claims 9 to 12).

  According to the data input / output program, since items other than the management items are stored in the data storage unit without being encrypted, it is not necessary to decrypt the data every time a data read request is received from the user.

In the above data input / output program, if there is a data comparison process for comparing the data read from the data storage unit with the decrypted data and a management item that does not match as a result of the comparison, the management item A data recovery process for updating the data stored in the data storage unit with the decrypted data may be executed (claim 10).
In this way, the management item can be detected and recovered when the data stored without encryption is falsified.

In the above data input / output program, prior to the data writing step, the management item specifying information different from the item specifying information for specifying the item in the data is acquired for each management item in the computer, and the item specifying information and the management item are acquired. A management item definition process in which the specific information is associated with the specific information and written in the management item definition storage unit may be executed.
In this way, if the third party succeeds in obtaining the user's encryption key, the third party does not know the correspondence of the items between the input data and the encrypted data. However, the encrypted data cannot be falsified as intended.

In the data input / output program, the data includes user identification information for identifying the user as an item, and in the data writing process, the user identification information is encrypted with a predetermined system encryption key and stored in the data storage unit. In the writing and data comparison processing, the encryption key may be acquired by searching the management item definition storage unit using the user identification information decrypted by the system encryption key as a search key.
In this way, unless the third party obtains the system encryption key, which user's encryption key should be used to decrypt the management item stored in the data storage unit. I can't know.

  According to the present invention, since items other than the management items are stored in the data storage unit without being encrypted, it is not necessary to decrypt the data every time a data read request is received from the user.

The configuration and operation of a computer 1 (an example of a data input / output device) according to an embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a functional block diagram of the computer 1.
The computer 1 is, for example, a server computer, and includes an input device 10 such as a keyboard and a mouse, an output device 20 such as a display device and a printing device, an application unit 30 that operates by program control, and a storage device 40 that stores information. Consists of
Further, the application unit 30 includes an application control unit 31, a management item definition unit 32, a user information management unit 33, an application data input / output unit 34, an application data encryption / decryption unit 35, and an application data comparison unit 36. And an application data recovery unit 37.
The storage device 40 is configured by, for example, a hard disk device, and includes a management item definition table 41 (an example of a management item definition storage unit), a user information management table 42 (an example of a user information storage unit), and an application data table 43 ( An example of the data storage unit) is stored.
Although FIG. 1 shows an example in which the storage device 40 is built in the computer 1, the storage device 40 may have any physical location as long as it is connected so as to be accessible from the computer 1. For example, a storage device connected to the computer 1 via a fiber channel may be used as the storage device 40.
Further, the input device 10 and the output device 20 may be connected to a client computer that uses a service provided by the computer 10.

The computer 1 generally has the following functions.
An encryption key different for each user is assigned in advance as part of the user authority definition and stored in the user information management table 42, and tampering checks are performed in the data items of the application data stored in the application data table 43. Data items to be performed (hereinafter referred to as “management items”) are specified by the management item definition unit 32 and stored in the management item definition table 41.

  When registering application data, the application control unit 31, the application data input / output unit 34, and the application data encryption / decryption unit 35 refer to the user information management table 42 and the management item definition table 41 to request registration of management items. The data value is encrypted with the encryption key given to the user, and the encrypted data value is stored in a different item from the original application data.

  When the application data is read, the application controller 31, the application data input / output unit 34, the application data encryption / decryption unit 35, the application data comparison unit 36, and the data read from the application data table 43 by the application data recovery unit 37 are processed. Check if the value of the data item is falsified by comparing whether the value of the original data item matches the value of the encrypted data item, and encrypt if the data has been falsified Restore the value of the data item to the value before falsification.

Next, functions of each unit of the computer 1 will be described in detail.
The application control unit 31 is called when the application program is started, executes a processing request given from the input device 10, and displays the execution result on the output device 20.
In addition, application data read from the application input / output unit 34 at the time of an application data input request is received.

  The management item definition unit 32 is called from the application control unit 31 when a request for processing of tampering check definition of an application data item is given from the input device 10. Based on an input instruction from the user, a management item and a data item as a storage destination are defined among data items stored in the application data table 43, and the definition result is stored in the management item definition table 41 as management item definition information. To do.

  The user definition information management unit 33 is called from the application control unit 31 when a request for use authority definition processing of the user of the application program is given from the input device 10. The user definition information (for example, user name) of the application program is checked and the encryption key for each user is generated, and the user definition information and the encryption key are associated with each other and stored in the user information management table 42. To do.

  The application data input / output unit 34 is called from the application control unit 31 when a request for saving or calling application data is given from the input device 10. The application data given from the application control unit 31 is stored in the application data table 43, or the application data is read from the application data table 43 under the specified conditions.

  When the instruction from the application control unit 31 is data storage, the management item definition information stored in the management item definition table 41 is referred to. The decryption unit 35 is called to perform encryption, and the encrypted data is stored in the application data table 43 as a data item different from the original data item. That is, the application data input / output unit 34 and the application data encryption / decryption unit 36 are examples of a data writing unit.

  In addition, when the instruction from the application control unit 31 is data reading, the management item definition information stored in the management item definition table 41 is referred to, and the data item for performing the tampering check in the data item of the stored data is displayed. If there is, the application data encryption / decryption unit 35 is called and decrypted to obtain decrypted data. Then, the read data is output as it is for items other than the management items, and the combined data is output to the output device 20 for the management items. That is, the application data input / output unit 34 and the application data encryption / decryption unit 36 are examples of a data reading unit.

  The application data encryption / decryption unit 35 is called from the application data input / output unit 34 and encrypts the given data based on the given encryption instruction or the data given based on the given decryption instruction. Decrypt. When data is encrypted or decrypted, an encryption key for the user is obtained from the user information management table 42 based on the user information given from the application data input / output unit 34, and the encryption key is obtained. Based on the above, data encryption or data decryption is performed.

  The application data comparison unit 36 (an example of a data comparison unit) is called from the application control unit 31 when the application data read from the application data input / output unit 34 is returned, and the management items stored in the management item definition table 34 With reference to the definition information, it is checked whether or not the data item to be tampered with matches the data item to be saved, and the result is notified to the application control unit 31.

  The application data recovery unit 37 (an example of a data recovery unit) is called from the application control unit 31 and updates the value of the data item that has been falsified with respect to the instructed application data to the value of the data item of the storage destination.

  Each unit described above is realized by the CPU of the computer 1 executing a program and controlling the hardware provided in the computer 1.

Next, the operation of the computer 1 will be described. The operation of the computer 1 is largely divided into operations of a preset process, an application data write process, and an application data read process.
Each movement will be described with reference to the flowcharts of FIGS. 1, 2, 3, and 4.
In FIG. 2 showing the operation of the presetting process, the presetting process S210 is further divided into steps of a user registration process S211 and a falsification management item definition process S211.
In the user registration process S211, the user information management unit 33 is called from the application control unit 31 and executed when a user-defined processing request for the application program 30 is given via the input device 10.
The user information management unit 33 checks the validity of the user definition information of the application program 30 given from the input device 10, and the user name (an example of user identification information) included in the user definition information of the application program 30. ) Is generated, and the user definition information and the encryption key of the application program 30 are stored in the user information management table 42 in a format that can be identified for each user. The registered information is output to the output device 20 via the application control unit 31.

The falsification management item definition process S212 is executed by calling the management item definition unit 32 from the application control unit 31 when the input device 10 receives a request for processing to define the falsification check of the application data item.
The management item definition unit 32 displays a list of data items stored in the application data table 43 on the output device 20 via the application control unit 31, and checks the tampering via the input device 10 and the application control unit 31. Receives information about the data item to be performed and the data item to be saved.

  FIG. 5 shows an example of information on the data item to be tampered and the data item to be stored passed from the input device 10, in which 511 is the table name of the application data table 43, and 512 is the application data table. Data item name (an example of item specifying information) 513 indicates whether or not the data item is to be falsified, “Y” indicates that falsification is to be checked, and “N” indicates that falsification is not to be checked. Yes. Reference numeral 514 denotes a data item name (an example of management item specifying information) in which a value obtained by encrypting the value of the data item is stored.

  The management item definition unit 32 checks the validity of the information regarding the received data item to be tampered with and the data item to be stored, and then uses these pieces of information as management item definition information for each table name in the application data table 43. It is stored in the management item definition table 41 in an identifiable format.

  Next, the application data writing process will be described with reference to FIG. The application data write process S310 is further divided into steps of an output application data acquisition process S311, an application data encryption process S312 and an application data output process S313.

The output application data acquisition process S311 is executed by calling the application data input / output unit 34 from the application control unit 31 when an output process request (write request) of application data of the application program is given via the input device 10.
The application data input / output unit 34 identifies the table name of the application data table 43 that is the output destination of the requested application data, and acquires management item definition information for the application data table 43 from the management item definition table 41. .

Next, it is determined whether or not each data item in the management item definition information is a data item subject to falsification management. If the data item is subject to falsification management, an application data encryption process S312 is executed. This determination is repeated for all data items.
The application data encryption process 312 step is executed by calling the application data encryption / decryption unit 35 from the application data input / output unit 34.
The application data input / output unit 34 passes the user information of the user who requested the data output to the application data encryption / decryption unit 35 and the value of the data item to be encrypted.

  The application data encryption / decryption unit 35 acquires the encryption key of the user who made the input request from the user information management table 42, and encrypts the value of the data item passed using this encryption key. The encrypted result is returned to the application data input / output unit 34.

The application data output process S313 is executed after the determination of the falsification target for all data items and the encryption process for the values of the management items are completed.
The application data input / output unit 34 passes the user name of the user who requested the data output to the application data encryption / decryption unit 35. The application data encryption / decryption unit 35 uses the encryption key (an example of a system encryption key) held by the application encryption / decryption unit 35 as a data value in the program. And the encrypted result is returned to the application data input / output unit 34.

  The application data input / output unit 34 refers to the management item definition information for the application data requested to be output obtained in the output application data acquisition process S311 and the encrypted value obtained in the application data encryption process S312. Are output to the application data table 43 together with the encrypted user name value.

FIG. 6 is an example of application data stored in the application data table 43.
In the figure, reference numeral 521 denotes unencrypted data having item names (an example of item specifying information) of “transaction number”, “registrant”, “transaction date”, “transaction content”, “transaction amount”, and “remarks”. Contains items. Reference numeral 522 denotes encrypted data, each item having item names (an example of management item specifying information) of “item 1”, “item 2”, “item 3”, “item 4”, “item 5”, and “item 6”. Contains. Each item name is associated according to the rule shown in FIG. For example, “item 1” corresponds to “transaction date”, and the value is “74GgiY45” obtained by encrypting “2006/05/05” with the encryption key of the registrant “Smith”.
“Item 6” stores a value “vGz3s” obtained by encrypting user information with a system encryption key.

  Next, application data read processing will be described with reference to FIG. The application read process 410 is further divided into steps of an output application data read acquisition process S411, an application data decryption process S412, an application data comparison process S413, an application recovery process S414, and an application data confirmation process S415.

The application data reading process S411 is executed by calling the application data input / output unit 34 from the application control unit 31 when an input process request for application data of the application program is given via the input device 10.
The application data input / output unit 34 identifies the table name of the application data table 43 that is the input source of the requested application data, and acquires management item definition information for the application data table from the management item definition table 41. Next, the designated application data is acquired from the application data table 43. The encrypted user name value stored in the acquired application data is passed to the application data encryption / decryption unit 35.

  The application data encryption / decryption unit 35 decrypts the user name value passed by using the encryption key held by the application encryption / decryption unit 35, and outputs the decrypted result to the application data input / output Return to section 34.

  The application data input / output unit 34 determines whether each data item in the management item definition information is a management item, and executes the application data decrypting process S412 in the case of a data item subject to falsification management. This determination is repeated for all data items.

The application data decryption process S412 is executed by calling the application data encryption / decryption unit 35 from the application data input / output unit 34.
The application data input / output unit 34 passes the decrypted user name and the value of the data item to be decrypted to the application data encryption / decryption unit 35.
The application data encryption / decryption unit 35 obtains the encryption key of the corresponding user from the user information management table 42, decrypts the value of the data item passed using this encryption key, and decrypts it. The result is returned to the application data input / output unit 34.

  The application data comparison process S413 is executed after determining whether or not all data items are subject to falsification check and completing the decryption process for the value of the corresponding data item. The application data input / output unit 34 refers to the management item definition information, and in step 412 the values of the data items read in the application data reading process S411 and the application data decoding process 412 for all the data items that are subject to falsification management. The obtained decrypted values are compared to determine whether they match. If there is a data item that does not match the value of the decrypted data item among the data items to be falsified and managed, the application data recovery process S414 is executed.

  In step S414 of the application data recovery process, a notification that application data falsification has occurred and an inquiry as to whether or not to recover the value of the corresponding data item are output to the output device 20 via the application control unit 31. When a request for restoring application data is given to the application control unit 31 via the input device 10, the application control unit 31 calls and executes the application data input / output unit 34.

The application data input / output unit 34 replaces the value of the decrypted data item for each management item that does not match, stores it in each data item of the application data table 43, and stores it in the application data table 43. Update data.
The application data confirmation process S415 is executed when there is no falsified data item as a result of the application data comparison process S413, or when the application data recovery process 414 step ends.
The application data input / output unit 34 outputs the requested application data obtained in the application data reading process 411 step or the application data recovery process 414 to the output device 20 via the application control unit 31.

  The first effect of the present embodiment is that malicious data is stored in the application data table together with encrypted values for data items that are subject to falsification management for the application data requested to be output from the user. Even if a third party who directly updates the value of the data stored in the application data table 43, it can be confirmed that the application program has been tampered with when reading the data, and the value before the tampering can be obtained. It can be returned.

  The second effect of the present embodiment is that it is possible to define the data item of the encrypted data storage destination of the falsification management target data item. This is because the item cannot be identified as the original data item.

  The third effect of the present embodiment is that the application data is encrypted for each user, and the user name that is the source of the application data encryption key is also encrypted with the system-specific encryption key. It is difficult to obtain information on the encryption key for decrypting the encryption from

  The fourth effect of the present embodiment is that the data format of the application data requested to be output is stored in the requested format, so that the data value is the intended value even when the data is directly extracted from the application data table. It can be referred to.

It is a functional block diagram of a computer which is one embodiment of the present invention. It is a flowchart explaining a prior setting process. It is a flowchart explaining application data write-out processing. It is a flowchart explaining an application data read-out process. It is a figure which shows an example of the information of the data item which performs a tampering check, and the data item used as a save destination. It is a figure which shows an example of application data.

Explanation of symbols

1 Computer 30 Application Unit 32 Management Item Definition Unit 33 User Information Management Unit 34 Application Data Input / Output Unit 35 Application Data Encryption / Decryption Unit 36 Application Data Comparison Unit 37 Application Data Recovery Unit 40 Storage Device 41 Management Item Definition Table 42 Usage Information management table 43 Application data table

Claims (12)

A user information storage unit for storing user identification information for identifying a user and an encryption key defined for each user in association with each other;
When there is a write request for data including a plurality of items, the encryption key of the user who made the request is read from the user information storage unit, and the read encryption key is a part of the item. A data writing unit that encrypts a certain management item to generate encrypted data, and writes the data and the encrypted data to a data storage unit;
When there is a request to read the data, the data read from the data storage unit is stored for items other than the management item, and the encryption of the user who has made the write request for the management item. A data reading unit that reads a key from the user information storage unit and decrypts the encrypted data using the read encryption key, and outputs the decrypted data to an output device, respectively. Data input / output device. For the management item, a data comparison unit that compares the data read from the data storage unit and the decoded data;
A data recovery unit that updates the data stored in the data storage unit with the decrypted data when the management item does not match as a result of the comparison; The data input / output device according to claim 1.   For each of the management items, management item specifying information different from item specifying information for specifying the item in the data is acquired, and the item specifying information and the management item specifying information are associated with each other in the management item definition storage unit. The data input / output device according to claim 1, further comprising a management item definition unit for writing. The data includes user specifying information for specifying the user as the item,
The data writing unit encrypts the user identification information with a predetermined system encryption key and writes the encrypted information to the data storage unit;
The said data comparison part searches the said management item definition memory | storage part by using the said user specific information decrypted with the said system encryption key as a search key, The said encryption key is acquired. Data input / output devices. A user information storage step of storing the user identification information for identifying the user in association with the encryption key determined for each user in the user information storage unit;
When there is a write request for data including a plurality of items, the encryption key of the user who made the request is read from the user information storage unit, and the read encryption key is a part of the item. A data writing step of encrypting a certain management item to generate encrypted data, and writing the data and the encrypted data into a data storage unit;
When there is a request to read the data, the data read from the data storage unit is stored for items other than the management item, and the encryption of the user who has made the write request for the management item. A data reading step of reading out a key from the user information storage unit and decrypting the encrypted data using the read encryption key and outputting the decrypted data to an output device, respectively. Data input / output method. For the management item, a data comparison step for comparing the data read from the data storage unit and the decoded data;
A data restoration step of updating the data stored in the data storage unit with the decrypted data for the management item when there is the management item that does not match as a result of the comparison; The data input / output method according to claim 5.   Prior to the data writing step, for each management item, management item specifying information different from item specifying information for specifying the item in the data is acquired, and the item specifying information and the management item specifying information are associated with each other. The data input / output method according to claim 5 or 6, further comprising a management item definition step for writing to the management item definition storage unit. The data includes user specifying information for specifying the user as the item,
In the data writing step, the user specifying information is encrypted with a predetermined system encryption key and written to the data storage unit,
The said data comparison process searches the said management item definition memory | storage part by using the said user specific information decrypted with the said system encryption key as a search key, The said encryption key is acquired. Data input / output method. On the computer,
User information storage processing for storing user identification information for identifying a user and an encryption key determined for each user in association with each other in a user information storage unit;
When there is a write request for data including a plurality of items, the encryption key of the user who made the request is read from the user information storage unit, and the read encryption key is a part of the item. A data write process for encrypting a certain management item to generate encrypted data, and writing the data and the encrypted data to a data storage unit;
When there is a request to read the data, the data read from the data storage unit is stored for items other than the management item, and the encryption of the user who has made the write request for the management item. A data read process for reading out a key from the user information storage unit and outputting the decrypted data generated by decrypting the encrypted data with the read encryption key to an output device, respectively. Data input / output program. In the computer,
For the management item, a data comparison process for comparing the data read from the data storage unit and the decoded data;
When there is the management item that does not match as a result of the comparison, a data recovery process for updating the data stored in the data storage unit with the decrypted data is executed for the management item The data input / output program according to claim 9. In the computer,
Prior to the data writing step, for each management item, management item specifying information different from item specifying information for specifying the item in the data is acquired, and the item specifying information and the management item specifying information are associated with each other. The data input / output program according to claim 9 or 10, further comprising executing management item definition processing to be written to the management item definition storage unit. The data includes user specifying information for specifying the user as the item,
In the data writing process, the user identification information is encrypted with a predetermined system encryption key and written to the data storage unit,
12. The data comparison process according to claim 11, wherein the encryption key is acquired by searching the management item definition storage unit using the user identification information decrypted by the system encryption key as a search key. Data input / output program.

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