JP6745864B2 - Confidential information management system - Google Patents

Description

The present invention relates to a technique for managing confidential information.

Considering the impact of information leakage, it is essential to encrypt electronic files containing confidential information. Various methods are used to encrypt electronic files. For example, in the technique described in Non-Patent Document 1, an electronic file stored in a designated place (for example, a local disk of a personal computer or a file server) is automatically encrypted. As long as it is managed in the designated place, the encrypted electronic file does not need to be explicitly decrypted by the user, and can be used as it is in the existing application. Even if the electronic file is leaked, the leaked confidential information can be prevented because the leaked electronic file is encrypted.

Further, as a method of easily encrypting an electronic file, there is a method of using a password function provided in applications such as word processing software, spreadsheet software and database software. The user sets a password for the electronic file by using the function of the application and encrypts the electronic file. When operating an electronic file with a password, the user inputs the password. If the entered password is correct, the electronic file is decrypted and the electronic file can be operated. Even if the electronic file is leaked, the contents of the electronic file cannot be viewed without knowing the password, so that confidential information can be prevented from leaking.

"InfoCage FileShell", [online], NEC Corporation, [Search on December 3, 2018], Internet <URL: https://jpn.nec.com/infocage/fileshell/>

However, when an electronic file stored in a specified location is automatically encrypted, if the size of the encrypted electronic file is very large, there is a problem that the application that handles the electronic file becomes unresponsive. It was For example, when managing tens of thousands of customer information in a database file stored in an automatically encrypted location, accessing the encrypted database file with a database application may cause the database application to become unresponsive. May occur. Therefore, when the database file is used, it may be unavoidably used in the non-encrypted area, resulting in a risk of leaking confidential information.

When the password function of the application is used, only one password can be registered in the electronic file, so one password must be disclosed to all users. There is a problem that a malicious user can easily leak the confidential information contained in the electronic file by leaking the electronic file and the password. Even if the user has no malicious intent, if the terminal is infected with a virus, the electronic file and password may be leaked, or the data contained in the electronic file may be lost. Further, it is desirable that the password is complicated and irregular, but if the password is made too complicated, it becomes almost impossible to memorize the password and the convenience of the user is impaired. Furthermore, since the management of passwords is left to each user, it is difficult to know whether the passwords are handled properly.

As a method of not exposing the password to the user, there is a method of embedding the password of the electronic file in the application. User authentication is controlled by the application. By embedding the password in the application, it is not necessary to disclose the password to the user, and the password can be made more complicated. As a result, even if a malicious user leaks the electronic file, the password is unknown and the risk of leakage of confidential information can be reduced.

However, if the password is embedded in the application, the application must be redistributed every time the password is changed.

The present invention has been made in view of the above, and an object thereof is to prevent leakage of confidential information included in an electronic file without impairing the convenience of the user.

Client confidential information management system according to the present invention, utilizing the administrator terminal to encrypt sensitive information file in the access password, the confidential information file and password management system for managing public password to generate the access password In the confidential information management system having a terminal , the password management device includes a storage unit that holds the public password, and a notification unit that notifies the public password in response to a request from the client terminal, and the administrator terminal includes a registration unit that stores accepting registration of a public password to the password management device holds a secret key, a generation unit to generate an access password from the private key and the public password, the secret in the access password The client terminal includes a setting unit for encrypting an information file , the client terminal holds an acquisition unit for acquiring the public password from the password management device, the private key, and stores the access password from the private key and the public password. An electronic unit that stores an application that handles the confidential information file expanded to include the secret key, is automatically provided by a generating unit that generates the access information, and an access unit that accesses the confidential information file using the access password. It is characterized in that it is stored in an encrypted place and the computer is made to execute the application to function as each unit of the client terminal .

In the confidential information management system, the registration unit adds a predetermined character string to the public password when the input public password does not meet a predetermined standard, and the public password added with the predetermined character string. Is stored in the password management device, and the generation unit generates the access password from the public password provided with the secret key and the predetermined character string .

In the confidential information management system, the registration unit receives an instruction to update the public password, generates the public password composed of an arbitrary character string, and stores the public password in the password management device .

According to the present invention, leakage of confidential information contained in an electronic file can be prevented without impairing the convenience of the user.

It is the whole block diagram which includes the classified information management system of this execution form. It is a functional block diagram which shows the structure of a password management apparatus. It is a figure which shows the example of the access password automatically generated from the public password. It is a functional block diagram which shows the structure of a client terminal. It is a sequence diagram which shows the flow of a process of a confidential information management system. It is a sequence diagram which shows the flow of another process in which a confidential information management system sets a password to a confidential information file.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall configuration diagram including a confidential information management system of this embodiment. The confidential information management system in FIG. 1 has an administrator terminal 1, one or more client terminals 2, and a password management computer 3. The administrator terminal 1, the client terminal 2, and the password management computer 3 are connected via a network. A confidential information file server 4 that stores a confidential information file is connected to the network and is accessible from the administrator terminal 1 and the client terminal 2.

The confidential information file is an electronic file that is encrypted with an access password and can be shared by multiple users. The confidential information file is, for example, a database file in the MDB format or the ACCB format. The confidential information file is not limited to the database file, and may be another type of file as long as the password can be set in the file.

The access password set in the confidential information file is generated from the public password managed by the password management computer 3 and the private key held by the administrator terminal 1 and the client terminal 2.

The administrator terminal 1 is a terminal for managing the confidential information file. The administrator terminal 1 stores the public password in the password management computer 3, converts the public password with a secret key to generate an access password, and encrypts the confidential information file using the generated access password.

The client terminal 2 is a terminal for using the confidential information file. When the client terminal 2 accesses the confidential information file, the client terminal 2 queries the password management device 3 for the public password, converts the obtained public password with the private key to generate the access password, and uses the generated access password. Access sensitive information files.

The administrator terminal 1 and the client terminal 2 hold a common secret key and generate an access password by a common conversion method. The client terminal 2 used by the administrator may be used as the administrator terminal 1.

The password management computer 3 manages the public password. The password management computer 3 receives and holds the public password from the administrator terminal 1. The password management computer 3 returns the public password in response to requests from the administrator terminal 1 and the client terminal 2.

The confidential information file server 4 holds the confidential information file. The devices that can access the confidential information file server 4 may be limited to the administrator terminal 1 and the client terminal 2. Since the confidential information file is encrypted with the access password, even if the confidential information file leaks, the information in the confidential information file will not be leaked unless the access password is known. The access password is generated based on the public password and private key when accessing the confidential information file, so the user never sees the access password directly, and all of the public password, private key, and conversion method are used. Access password cannot be generated without knowing.

Next, the administrator terminal 1, the password management computer 3 and the client terminal 2 of this embodiment will be described.

FIG. 2 is a functional block diagram showing configurations of the administrator terminal 1 and the password management computer 3 of this embodiment.

The administrator terminal 1 has a registration unit 11, a generation unit 12, and a setting unit 13.

When the public password is input, the registration unit 11 stores the public password in the password management device 3 and passes the public password to the generation unit 12.

The generation unit 12 holds the secret key, and when receiving the public password, generates the access password from the secret key and the public password. The generation unit 12 generates, as the access password, for example, an access password having a length obtained by arranging 20 characters of 256 kinds of characters in which half-width characters and full-width characters are mixed. In this case, there are 1.46×10 ⁴⁸ access passwords.

FIG. 3 shows an example of a public password and an access password automatically generated based on the public password. For example, even if the public passwords are all the same characters as shown in FIG. 3A, or if the public password is a repetition of short phrases as shown in FIG. A complex access password with mixed characters is generated. In addition, even if the public password differs by only one character as shown in FIG. 3C, or if the public password differs for half-width characters and full-width characters as shown in FIG. 3D, they are completely different and complicated. Access password is generated.

The setting unit 13 sets the access password generated by the generating unit 12 in the confidential information file held by the confidential information file server 4, and encrypts the confidential information file. The administrator terminal 1 discards the access password used for encryption without storing it.

The password management computer 3 has a notification unit 31 and a storage unit 32.

The notification unit 31 notifies the public password stored in the storage unit 32 to the administrator terminal 1 and the client terminal 2 in response to requests from the administrator terminal 1 and the client terminal 2.

The storage unit 32 stores the public password. The public password may be stored in a location that is automatically encrypted by the technique of Non-Patent Document 1.

FIG. 4 is a functional block diagram showing the configuration of the client terminal 2 of this embodiment.

The client terminal 2 has an acquisition unit 21, a generation unit 22, and an access unit 23.

The acquisition unit 21 requests the public password from the password management computer 3, receives the public password, and passes the public password to the generation unit 22. Since the acquisition unit 21 acquires the public password from the password management device 3 when accessing the confidential information file, the user does not need to remember the public password, and the administrator uses the fact that the public password has been changed. There is no need to notify the person.

The generation unit 22 holds the same secret key as the generation unit 12 of the administrator terminal 1, and when receiving the public password, generates the access password from the secret key and the public password in the same method as the generation unit 12.

The access unit 23 uses the access password generated by the generation unit 22 to access the confidential information file held by the confidential information file server 4. After accessing the confidential information file, the client terminal 2 discards the access password without storing it.

Each unit included in the administrator terminal 1, the client terminal 2, and the password management computer 3 may be configured by a computer including an arithmetic processing unit, a storage device, etc., and the processing of each unit may be executed by a program. This program is stored in a storage device included in the administrator terminal 1, the client terminal 2, and the password management computer 3, and can be recorded in a recording medium such as a magnetic disk, an optical disk, a semiconductor memory, or provided through a network. It is possible.

It is conceivable that the administrator terminal 1 and the password management computer 3 are configured by one device, but the public password and the secret key are present in one device. Therefore, from the viewpoint of security, it is preferable to configure the administrator terminal 1 and the password management computer 3 as separate devices as in the present embodiment.

The administrator terminal 1 and the client terminal 2 may be configured by customizing/extending an application that handles confidential information files. For example, the functions of the acquisition unit 21, the generation unit 22, and the access unit 23 are implemented using the programming language provided to extend the function of the application. The extended application may be stored in a location automatically encrypted by the technique of Non-Patent Document 1. As a result, it is possible to prevent leakage of the private key and the like due to reverse engineering.

Next, the operation of the confidential information management system of this embodiment will be described.

FIG. 5 is a sequence diagram showing the flow of processing of the confidential information management system of this embodiment. In the figure, the encryption processing of the confidential information file and the access processing to the encrypted confidential information file are shown.

First, the encryption processing of the confidential information file will be described.

When the administrator inputs the public password to the administrator terminal 1, the administrator terminal 1 sends the public password to the password management device 3, and the password management device 3 registers the public password in the storage unit 32 (step S11). ..

When the new public password is registered, the administrator terminal 1 generates an access password from the private key and the new public password (step S12).

The administrator terminal 1 encrypts the confidential information file held by the confidential information file server 4 with the access password generated in step S12 (step S13). The administrator terminal 1 discards the access password after encrypting the confidential information file.

Through the above processing, the confidential information file is encrypted with the access password.

When updating the access password, the administrator terminal 1 generates a new access password from the new public password and a current access password from the old public password in step S12. The old public password can be acquired from the password management computer 3. In step S13, the administrator terminal 1 decrypts the confidential information file with the current access password, and then encrypts the confidential information file with the new access password. After encrypting the confidential information file with the new access password, the old public password may be deleted from the password management computer 3.

When the public password input in step S11 does not satisfy the predetermined criterion, the registration unit 11 adds a predetermined character string to the public password, and the public password added with the predetermined character string is used as the password management device 3 It may be stored in the memory and passed to the generation unit 12. For example, when the predetermined standard of the public password is 6 characters or more and the public password of 5 characters or less is input in step S11, the registration unit 11 does not input the public password again, and a fixed character string is input. Add, repeat the entered public password to meet a predetermined criterion, or repeat the entered public password in reverse order. Alternatively, if the predetermined criterion for the public password is to include all alphanumeric characters and symbols, then the types of characters that it does not include may be added.

Next, a process of accessing the confidential information file will be described.

The client terminal 2 requests the public password from the password management computer 3 (step S21).

The password management computer 3 notifies the public password in response to the request from the client terminal 2 (step S22). The password management computer 3 may notify the public password after authenticating the client terminal 2. The password management computer 3 may notify the public password to the client terminal 2 in plain text. Even if the public password can be obtained by a third party, the third party cannot access the confidential information file unless he/she knows how to convert the public password into the private key and the access password.

Upon receiving the public password, the client terminal 2 generates an access password from the private key and public password (step S23).

The client terminal 2 accesses the confidential information file held by the confidential information file server 4 with the access password generated in step S23 (step S24). The confidential information file server 4 may permit access to the confidential information file after authenticating the client terminal 2. After accessing the confidential information file, the client terminal 2 discards the access password.

If there are multiple confidential information files, a public password may be set for each confidential information file. For example, in step S11, the administrator terminal 1 transmits the information (file name etc.) of the confidential information file to be encrypted and the public password to the password management computer 3, and the password management computer 3 discloses the confidential information file and the public information. The password set is registered in the storage unit 32. When accessing the confidential information file, the client terminal 2 sends the information of the confidential information file to be accessed to the password management computer 3 to request the public password in step S21. In step S22, the password management computer 3 notifies the client terminal 2 of the public password corresponding to the confidential information file.

Next, another process for setting a password in the confidential information file will be described.

FIG. 6 is a sequence diagram showing another flow of processing in which the confidential information management system of this embodiment sets a password in the confidential information file. In the process of FIG. 6, when the administrator terminal 1 receives a public password update request, the administrator terminal 1 itself generates a public password. Since the password management computer 3 manages the public password and returns the public password in response to the request, the administrator and the user do not need to know the public password.

Upon receiving the request for updating the public password, the administrator terminal 1 generates a public password (step S31) and registers the generated public password in the password management computer 3 (step S32).

The administrator terminal 1 creates an access password from the private key and the public password created in step S32 (step S33).

The administrator terminal 1 encrypts the confidential information file held by the confidential information file server 4 with the access password generated in step S33 (step S34). The administrator terminal 1 discards the access password after encrypting the confidential information file.

Access to the confidential information file can be performed by the same processing as steps S21 to S24 in FIG.

As described above, according to this embodiment, the administrator terminal 1 accepts registration of a public password, stores the public password in the password management device 3, and generates an access password from the private key and the public password to access the public password. By setting the password in the confidential information file, the client terminal 2 requests the public password from the password management computer 3, generates an access password from the private key and the public password, and accesses the confidential information file using the access password. Since the password management device 3 manages the public password and inquires the public password every time the client terminal 2 accesses the confidential information file, the burden of updating and managing the password can be reduced. Further, since the administrator terminal 1 and the client terminal 2 hold a common secret key, and when the client terminal 2 accesses the confidential information file, the access password set in the confidential information file is generated from the secret key and the public password. , It is possible to prevent the access password of confidential information file from leaking.

DESCRIPTION OF SYMBOLS 1... Administrator terminal 11... Registration part 12... Generation part 13... Setting part 2... Client terminal 21... Acquisition part 22... Generation part 23... Access part 3... Password management device 31... Notification part 32... Storage part 4... Confidential information file server

Claims (3)

A secret information management system having a client terminal using the administrator terminal to encrypt sensitive information file in the access password, the confidential information file and password management system for managing public password to generate the access password ,
The password management device,
A storage unit that holds the public password ,
A notification unit for notifying the public password in response to a request from the client terminal,
The administrator terminal is
A registration unit that accepts registration of a public password and stores it in the password management device;
A generation unit that holds a private key and generates an access password from the private key and the public password,
Comprising a setting unit for encrypting said confidential information file with the access password,
The client terminal is
An acquisition unit for acquiring the public password from the password management device,
A generation unit that holds the secret key and generates the access password from the secret key and the public password;
An access unit for accessing the confidential information file using the access password,
An application that handles the confidential information file extended so as to include the secret key is stored in a location where the stored electronic data is automatically encrypted, and the computer is caused to execute the application so that each unit of the client terminal is executed. A confidential information management system characterized by functioning as . The registration unit adds a predetermined character string to the public password when the input public password does not satisfy a predetermined standard, and stores the public password with the predetermined character string in the password management device. Let
The confidential information management system according to claim 1, wherein the generation unit generates the access password from the secret password and a public password to which the predetermined character string is added . The confidential information management system according to claim 1, wherein the registration unit receives an instruction to update the public password, generates the public password including an arbitrary character string, and stores the public password in the password management device. ..

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