JP4665495B2 - Information processing device - Google Patents

Description

  The present invention relates to an information processing apparatus in an information security system that ensures confidentiality of information.

  In recent years, damage caused by theft of information such as personal information by third parties has been increasing.

  Theft in the information distribution process or the client terminal itself storing the information is stolen so that highly confidential information is illegally used by a third party.

  In order to prevent unauthorized use of information due to the former theft, it is known to distribute encrypted information on a network. In this way, even if information is illegally stolen on the network, unauthorized use of information by a third party can be prevented. For example, when a certain user downloads a file from the file server to the client terminal, the file server transmits the encrypted file to the client terminal via the network. The client terminal receives the encrypted file via the network and decrypts the file based on the decryption key. In this way, the user can use the file.

On the other hand, in order to prevent unauthorized use of information due to the latter theft, the client terminal can only store encrypted files, authenticate the user when using the encrypted files, Patent Document 1 discloses that the encrypted file is decrypted only when authenticated. In this way, even when the client terminal is stolen and illegally operated, a third party cannot decrypt the encrypted file, and can prevent unauthorized use of information.
JP-A-10-105470

  However, if an encrypted file stored in the client terminal is decrypted in a normal procedure and then the client terminal is stolen while being used in the client terminal, the decryption can also be performed by a third party. It becomes possible to use the converted file. That is, if a client terminal is stolen while a file is being used, the security of the file cannot be ensured.

  The present invention has been made in view of such problems, and provides an information processing apparatus that can ensure the security of information even if a client terminal is stolen while the user is using the information. The purpose is to do.

  In order to solve the above-mentioned problem, in the present invention, when it can be determined that the client terminal has been stolen, the currently used information cannot be used, and thereafter, the use of the information is prohibited. We focused on the fact that we can prevent unauthorized use of information.

That is, the information processing apparatus according to the present invention includes an authentication requesting unit that transmits second information for authentication of the user input from the user to the server, a key storage unit, and the second information by the server. When user authentication using information is successful, a decryption key is received from the server , the decryption key is stored in the key storage unit, and the information storage is performed using the decryption key stored in the key storage unit. A decoding unit that decodes the first information stored in the unit, an information output unit that outputs the first information decoded by the decoding unit , and a connection status between the information processing apparatus and the server When the connection between the information processing apparatus and the server is disconnected, the output of the first information by the information output unit is forcibly terminated and the decryption key stored in the key storage unit and the connection status monitoring unit to remove, that includes the And butterflies.

  As described above, the present invention checks whether or not a client terminal that uses information is connected to the monitoring server when using the information. Use of information is allowed when connected. Also, while the information permitted to be used is being used, the connection status is monitored to see if it is connected to the monitoring server, and if the connection is cut off, the application that uses the information is stopped In addition to making it impossible to use information currently in use, it is prohibited to use further information. Therefore, even if the client terminal is stolen while the user is using information, unauthorized use can be prevented and information security can be ensured.

  According to the information processing apparatus of the present invention, when using the information, it is confirmed whether or not the client terminal that uses the information is connected to the monitoring server. Use of information is allowed when connected. Also, while the information that is permitted to be used is being used, the connection status is monitored to see if it is connected to the monitoring server, and if the connection is lost, the application that uses the information is stopped In addition to making it impossible to use information currently in use, it is prohibited to use further information. Therefore, even if the client terminal is stolen while the user is using information, unauthorized use can be prevented and information security can be ensured.

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

  A processing mode of the information security system according to the embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows a configuration of an information security system 1 comprising an authentication server 2, an information processing terminal 3, and a file server 5 interconnected via a network 4, such as the Internet, a telephone line network, and a LAN, according to an embodiment of the present invention. Is shown.

  As shown in FIG. 2, the authentication server 2 includes a CPU, a RAM, a ROM, a magnetic storage device, various interfaces, and the like. The magnetic storage device includes a communication control unit 21, a user management database 22, an encryption / decryption key database 23, a user authentication unit 24, an encryption / decryption key acquisition unit 25, and a user status sending unit 26 as shown in FIG. Programs and databases for realizing the functions are installed. These programs and databases are loaded into the RAM as necessary and executed by the CPU. As the authentication server 2, a computer such as a server computer, a workstation, or a personal computer is used.

  As shown in FIG. 3, the authentication server 2 of this embodiment includes a communication control unit 21, a user management database 22, an encryption / decryption key database 23, a user authentication unit 24, an encryption / decryption key acquisition unit 25, and a user status transmission. The unit 26 is configured.

  The communication control unit 21 controls transmission / reception of information.

  The user management database 22 stores, for each user identifier, user information such as a password and a group to which the user belongs, and the login status of the user. Here, the group in the present embodiment is, for example, a project, a group, a department, a section, or the like to which the user belongs.

  The encryption / decryption key database 23 stores, for each group, a decryption key and an encryption key used when decrypting or encrypting a file referred to or created in the group. That is, in this embodiment, the encryption key for encrypting the file and the decryption key for decrypting the encrypted file are made common within the group, and are set for each group. In this way, the troublesomeness of managing different keys for individuals can be eliminated, and encrypted files can be shared.

  The user authentication unit 24 refers to the user management database 22 and determines whether or not a user is registered in advance. That is, user authentication is performed. Further, when the user authentication is successful, the fact is stored in the user management database 22 to that effect.

  The encryption / decryption key acquisition unit 25 acquires an encryption key and a decryption key corresponding to the group to which the user authenticated by the user authentication unit 24 belongs from the encryption / decryption key database 23, and processes the acquired encryption key and decryption key as information processing. The communication control unit 21 is requested to transmit to the terminal 3. In other words, a user who succeeds in authentication is permitted to use a common encryption key and decryption key in the group to which the user belongs.

  The user status sending unit 26 displays on the display device provided in the information processing terminal 3 that the user authentication has been successful and the authentication server 2 is being logged in.

  Similar to the authentication server 2, the information processing terminal 3 includes a CPU, a RAM, a ROM, a magnetic storage device, various interfaces, and the like as shown in FIG. The magnetic storage device includes a communication control unit 31, a file management information storage unit 32, a file storage unit 33, a file management unit 34, an encryption / decryption key storage unit 35, a user authentication request unit 36, an encryption / decryption unit as shown in FIG. Programs and databases for realizing functions such as a decryption key storage unit 37, a file reference / update unit 38, an encryption / decryption unit 39, and a connection status monitoring unit 40 are installed. These programs and databases are loaded into the RAM as necessary and executed by the CPU. As the information processing terminal 3, a computer such as a workstation or a personal computer, a PDA, a mobile phone, or the like is used.

  As shown in FIG. 4, the information processing terminal 3 includes a communication control unit 31, a file management information storage unit 32, a file storage unit 33, a file management unit 34, an encryption / decryption key storage unit 35, a user authentication request unit 36, an encryption / Decryption key storage unit 37, file reference / update unit 38, encryption / decryption unit 39, and connection status monitoring unit 40.

  The communication control unit 31 controls transmission / reception of information.

  The file management information storage unit 32 stores, for each file, file attributes such as a group name to which the file belongs and a file storage location.

  The file storage unit 33 stores an encrypted file. Here, the file storage unit 33 has a hierarchical structure and corresponds to the file storage location of the file management information storage unit 32.

  The file management unit 34 refers to the file management information storage unit 32 and acquires an encrypted file from the file storage unit 33. In addition, when a file operation such as update or deletion of an encrypted file or a new file is created according to an instruction from the file reference / update unit 38 to be described later, the file is stored in the file storage unit 33 and the file The file attribute of the file is stored in the file management information storage unit 32.

  The encryption / decryption key storage unit 35 stores the encryption key and the decryption key received from the authentication server 2 for each group. In other words, since the encryption key and the decryption key are received from the authentication server 2 only when the user authentication is successful, the encryption key and the decryption key are stored in the encryption / decryption key storage unit 35 only when the user authentication is successful. It will be remembered.

  The user authentication request unit 36 requests the communication control unit 31 to activate the user authentication unit 24 of the authentication server 2.

  The encryption / decryption key storage unit 37 stores the encryption key and the decryption key received by the communication control unit 31 in the encryption / decryption key storage unit 35.

  The file reference / update unit 38 requests the file management unit 34 to perform a file operation or a new file creation. Specifically, when an encrypted file acquired by the file management unit 34 is requested to an encryption / decryption unit 39, which will be described later, to decrypt the encrypted file, and the decrypted file is updated, the file is encrypted. The encryption / decryption unit 39 is requested to store the encrypted data. The file reference / update unit 38 also has a function of a known document creation tool, and can refer to and update the decrypted file. Furthermore, a request similar to the request for the file management unit 34 is made to the file management unit 54 of the file server 5 to be described later via the network 4.

  The encryption / decryption unit 39 refers to the encryption / decryption key storage unit 35 and encrypts or decrypts the file requested by the file reference / update unit 38.

  The connection status monitoring unit 40 monitors the status of connection between the information processing terminal 3 and the authentication server 2. That is, referring to the user management database 22 of the authentication server 2, the connection status between the authentication server 2 and the information processing terminal 3 is monitored one by one, and if it is determined that the connection has been disconnected, the encryption / decryption key storage unit 35 Deletes the record stored in, and forcibly stops the use of the already used file. That is, the information processing terminal 3 of this embodiment can perform file operations on encrypted files only while connected to the authentication server 2. When the record is deleted from the encryption / decryption key storage unit 35, the file reference / update unit 38 is instructed to stop providing the document creation tool function. That is, when the connection with the authentication server 2 is disconnected, the information processing terminal 3 according to the present embodiment not only cannot decrypt the encrypted file but also references and updates the file decrypted during the connection. It is something that can not be done.

  Similar to the authentication server 2, the file server 5 includes a CPU, a RAM, a ROM, a magnetic storage device, various interfaces, and the like as shown in FIG. The magnetic storage device is installed with programs and databases for realizing functions such as the communication control unit 51, the file management information storage unit 52, the file storage unit 53, and the file management unit 54 as shown in FIG. . These programs and databases are loaded into the RAM as necessary and executed by the CPU. As the file server 5, a computer such as a server computer, a workstation, or a personal computer is used.

  As illustrated in FIG. 5, the file server 5 includes a communication control unit 51, a file management information storage unit 52, a file storage unit 53, and a file management unit 54.

  The communication control unit 51 controls transmission / reception of information.

  The file management information storage unit 52 stores, for each file, file attributes such as a group name to which the file belongs and a file storage location.

  The file storage unit 53 stores an encrypted file. Here, the file storage unit 53 has a hierarchical structure and corresponds to the file storage location of the file management information storage unit 52.

  The file management unit 54 refers to the file management information storage unit 52 and acquires an encrypted file from the file storage unit 53. Further, when a file operation such as update or deletion of an encrypted file or a new file is created in accordance with an instruction from the file reference / update unit 38 of the information processing terminal 3, the file is stored in the file storage unit 53. At the same time, the file attribute of the file is stored in the file management information storage unit 52. That is, the file server 5 has the same configuration as the file management information storage unit 32, the file storage unit 33, and the file management unit 34 of the information processing terminal 3. For the user who uses the file, the file stored in the file storage unit 33 of the information processing terminal 3 is used, or the file stored in the file storage unit 53 of the file server 5 is used via the network 4. The difference is what to do.

  In the present embodiment, as described above, the information processing terminal 3 and the file server 5 are described as configuring a file management information storage unit, a file storage unit, and a file management unit, respectively. For example, only the information processing terminal 3 includes the file management information storage unit 32, the file storage unit 33, and the file management unit 34, and the file server 5 is configured as the information security system 1. It may be excluded from the configuration. Conversely, only the file server 5 is configured to include a file management information storage unit 52, a file storage unit 53, and a file management unit 54. From the configuration of the information processing terminal 3, the file management information storage unit 32, the file The storage unit 33 and the file management unit 34 may be excluded.

  Next, the user decrypts the encrypted file stored in the file storage unit 53 of the file server 5 or the file storage unit 33 of the information processing terminal 3 by using the information processing terminal 3 to refer to the file. A process for referring to or updating the decrypted file using the document creation tool function of the update unit 38 will be described. In this embodiment, such processing is divided into three processes for convenience of explanation.

  FIG. 6 is a flowchart showing user authentication processing, which is the first processing of the information security system 1 in this embodiment.

  When the user activates the user authentication request unit 36 using an input device such as a keyboard or a mouse included in the information processing terminal 3, the user authentication request unit 36 communicates so as to activate the user authentication unit 24 of the authentication server 2. The control unit 31 is instructed (S6-1).

  When activated, the user authentication unit 24 instructs the communication control unit 21 to display a user authentication screen illustrated in FIG. 7 on the display device included in the information processing terminal 3 (S6-2).

  The user authentication screen illustrated in FIG. 7 includes a user ID input field, a password input field, a group input field, and a login button.

  The user ID input field is a field for the user to input a user identifier using an input device provided in the information processing terminal 3.

  The password input field is an area where the user inputs a password corresponding to the user identifier using the input device provided in the information processing terminal 3.

  The group input field is an area in which the user inputs the group name to which the user corresponding to the user identifier and password belongs using the input device provided in the information processing terminal 3.

  When the login button is selected by the user using the input device included in the information processing terminal 3, the login button acquires each information input in the user ID input field, the password input field, and the group input field, and stores the information. Processing to be sent to the user authentication unit 24 is executed.

  Here, the group in this embodiment is a group to which the user belongs. A user does not necessarily belong to one group, and may belong to a plurality of groups. Further, in the user authentication screen of the present embodiment, the group is input by the user, but it may be configured to log in to the group corresponding to the combination by inputting only the user identifier and the password. In this case, when the user belongs to a plurality of groups, it may be configured to select which group to log in to. Further, when a user inputs a user identifier, a list of groups to which the user belongs may be created, a group may be selected from the list, and then a password input may be requested.

  In this embodiment, the following description will be given on the assumption that the user has input “AAA” in the user ID input field, “BBB” in the password input field, and “railway project” in the group input field.

  When the user inputs “AAA” in the user ID input field, “BBB” in the password input field, and “Railway project” in the group input field, and the login button is selected, the user authentication unit 24 displays the user management database. Referring to FIG. 22, it is searched whether or not the input information is registered (S6-3).

  Here, FIG. 8 shows a configuration example of the user management database 22.

  The user management database 22 illustrated in FIG. 8 includes a user identifier field, a password field, a belonging group field, and a login presence / absence field.

  The user identifier field is a field for storing a user identifier.

  The password field is a field for storing a password corresponding to the user identifier.

  The belonging group field is a field for storing a group name corresponding to the user identifier and the password.

  The login presence / absence field is a field for storing the success of login when the user authentication is successful.

  For example, in the example of FIG. 8, the password of the user with the user identifier “XXX” is “YYY”, and the user belongs to the “railway project”, “financial project”, and “patent group”. I understand. Further, the user having the user identifier “AAA” belongs to the “Railway Project” if the password is “BBB”, and belongs to the “Financial Project” if the password is “DDD”. . In this way, it is possible to change the password for each group to which it belongs, and even if the password is illegally obtained by a third party, the damage is only the group corresponding to the password and affects other groups. There is nothing. Further, it can be seen that the user with the user identifier “AAA” is logged in to the “railway project”.

  If the user authentication unit 24 determines that the information input on the user authentication screen is registered in the user management database 22, the user authentication unit 24 regards that the user authentication has been successful and executes the process of S6-5 (S6-4 OK). . On the other hand, if it is determined that the information input on the user authentication screen is not registered in the user management database 22, it is assumed that the user authentication has failed, and the process ends (S6-4 NG).

  In this embodiment, the information input on the user authentication screen is the user identifier “AAA”, the password “BBB”, and the group “railway project”. Referring to the user management database 22 illustrated in FIG. 8, the input information is already registered, and the user authentication is successful. If the user authentication is successful, “logged in” is stored in the login presence / absence fields corresponding to the user identifier, password, and affiliation group as illustrated in FIG.

  Next, when user authentication is successful, the user authentication unit 24 activates the encryption / decryption key acquisition unit 25 (S6-5).

  When activated, the encryption / decryption key acquisition unit 25 refers to the encryption / decryption key database 23 and acquires an encryption key and a decryption key corresponding to the group to which the member belongs.

  Here, FIG. 9 shows a configuration example of the encryption / decryption key database 23.

  The encryption / decryption key database 23 illustrated in FIG. 9 includes an affiliation group field, a decryption key field, and an encryption key field.

  The belonging group field is a field for storing a group name to which the user belongs.

  The decryption key field is a field for storing, for each group, a decryption key that can decrypt an encrypted file belonging to the group.

  The encryption key field is a field for storing an encryption key for encrypting a file belonging to the group for each group. Here, the file encrypted based on the encryption key can be decrypted with the decryption key stored in the decryption key field corresponding to the encryption key.

  Referring to the encryption / decryption key database 23 illustrated in FIG. 9, the decryption key and the encryption key corresponding to the group name “railway project” input on the user authentication screen are “ABC” and “DEF”, respectively. Therefore, the encryption / decryption key acquisition unit 25 acquires “ABC” and “DEF” as the decryption key and the encryption key.

  Here, when there are a plurality of groups to which the user belongs or when there are a plurality of group names input on the user authentication screen, the corresponding decryption key and encryption key may be acquired respectively. . For example, a user whose user identifier is “XXX” belongs to three affiliation groups. Therefore, a decryption key and an encryption key corresponding to each group are acquired.

  When the encryption / decryption key acquisition unit 25 acquires the decryption key and encryption key corresponding to the belonging group, the encryption / decryption key acquisition unit 25 sends the belonging group name and the acquired decryption key and encryption key to the information processing terminal 3. Ask.

  When the communication control unit 31 receives the belonging group name, the decryption key, and the encryption key from the communication control unit 21 of the authentication server 2, the communication control unit 31 activates the encryption / decryption key storage unit 37.

  When activated, the encryption / decryption key storage unit 37 stores the received encryption key and decryption key in the encryption / decryption key storage unit 35 in association with the belonging group (S6-6).

  Here, FIG. 10 shows a configuration example of the encryption / decryption key storage unit 35.

  The encryption / decryption key storage unit 35 illustrated in FIG. 10 includes an belonging group field, a decryption key field, and an encryption key field.

  The belonging group field is a field for storing a group name.

  The decryption key field is a field that stores a decryption key that is associated with a group and that can decrypt an encrypted file that belongs to the group.

  The encryption key field is a field that stores an encryption key that is associated with a group and can encrypt a file that belongs to the group.

  As described above, the encryption / decryption key storage unit 35 stores information on the decryption key and the encryption key used in the group to which the user who has been successfully authenticated by the authentication server 2 belongs.

  When the encryption / decryption key storage unit 37 stores the encryption key and the decryption key in the encryption / decryption key storage unit 35, the encryption / decryption key storage unit 37 requests the communication control unit 21 to activate the user status transmission unit 26 of the authentication server 2.

  When activated, the user status sending unit 26 displays a login screen as illustrated in FIG. 11 on a display device included in the information processing terminal 3.

  The login screen illustrated in FIG. 11 includes a user ID output field, a group output field, and a logout button.

  The user ID output field is an area for displaying a user identifier of a user who has succeeded in user authentication.

  The group output field is an area for displaying a group name to which a user who has succeeded in user authentication belongs.

  When the logout button is selected by the user, the logout process described later is executed.

  In this embodiment, when the user authentication is successful and the encryption / decryption key storage unit 35 stores the encryption key and the decryption key corresponding to the belonging group, as shown in FIG. The login screen will be displayed on the device. Further, when the user with the user identifier “XXX” is normally authenticated, the screen is displayed as illustrated in FIG. 11B. That is, the logged-in screen indicates which group the currently logged-in user can access. For example, in the example of FIG. 11A, it can be seen that the user having the user ID “AAA” has obtained the decryption key and the encryption key used in the “railway project”. In the example of FIG. 11B, the user who is the user “XXX” has obtained the decryption key and the encryption key used in the “railway project”, “financial project”, and “patent group”. I understand.

  Next, the user uses the information processing terminal 3 to perform a file operation on the encrypted file stored in the file storage unit 53 of the file server 5 or the file storage unit 33 of the information processing terminal 3. The second process will be described.

  FIG. 12 is a flowchart showing the file reference / update process, which is the second process of the information security system 1 in this embodiment.

  First, the user activates the file reference / update unit 38 using an input device such as a keyboard or a mouse provided in the information processing terminal 3 (S12-1).

  Next, the file reference / update unit 38 activates the file management unit 34 or the file management unit 54. In this embodiment, the following description will be made with an example in which the file management unit 34 is activated.

  When activated, the file management unit 34 refers to the file management information storage unit 32 and acquires file attribute information. When the file management unit 54 is activated, the file attribute information is acquired with reference to the file management information storage unit 52.

  Here, FIG. 13 shows a configuration example of the file management information storage unit 32 of the information processing terminal 3, and FIG. 14 shows a configuration example of the file management information storage unit 52 of the file server 5.

  The file management information storage unit 32 and the file management information storage unit 52 illustrated in FIG. 13 and FIG. 14 each include a file name field, a belonging group field, and a storage location field.

  The file name field is a field for storing the name of the file. In this embodiment, the file name will be described. However, the present invention is not limited to this, and any file can be used as long as the file can be uniquely identified.

  The belonging group field is a field for storing a group name to which the file belongs.

  The storage location field is a field for storing the storage location of the file.

  In the example shown in FIG. 13, the file “railway project plan” belongs to the group “railway project”, and this file is stored in the “railway project folder” of the file storage unit 33. Show. Similarly, it can be seen that the “railway system design document” belongs to the group “railway project” and is stored in the “railway project folder”. It can also be seen that the “patent specification” belongs to the group “patent group” and is stored in the “patent group folder”.

  In the example shown in FIG. 14, the file “Railway Project Budget” belongs to “Railway Project”, and this file is stored in “Railway Project Folder” of the file storage unit 53. Show. Similarly, the “financial project budget document” belongs to the group “financial project” and is stored in the “financial project folder”. It can also be seen that the “patent application number management document” belongs to the group “patent group” and is stored in the “patent group folder”.

  When the file management unit 34 acquires the file attribute information from the file management information storage unit 32, the file management unit 34 displays a document list screen as illustrated in FIG. 15A on the display device included in the information processing terminal 3.

  Here, FIG. 15A shows an example in which information stored in the file management information storage unit 32 is edited and displayed. The user can operate the selected file by selecting the file name displayed on the document list screen using the input device.

  When the file management unit 54 is activated, the file management unit 54 obtains the file attribute information from the file management information storage unit 52 and is displayed on the display device included in the information processing terminal 3 as illustrated in FIG. The document list screen will be displayed.

  In the present embodiment, the following description will be given on the assumption that the “railway project plan” on the document list screen illustrated in FIG.

  When “Railway project plan” is selected, the file management unit 34 refers to the file storage unit 33, acquires the corresponding file, and sends the file to the file reference / update unit 38 (S12-2). ). As described above, all the files stored in the file storage unit 33 are encrypted.

  When receiving the encrypted file “railway project plan” from the file management unit 34, the file reference / update unit 38 activates the encryption / decryption unit 39.

  When activated, the encryption / decryption unit 39 refers to the encryption / decryption key storage unit 35 and searches for a decryption key corresponding to the group to which the file received by the file management unit 34 belongs (S12-3).

  If there is a decryption key corresponding to the group to which the file belongs, the process of S12-4 is executed (S12-3 OK). If the decryption key corresponding to the group to which the file belongs does not exist, the user is not authorized to operate the file because the authentication server 2 has not been authenticated for the group to which the file belongs. The process is terminated (S12-3 NG).

  In this embodiment, the “railway project plan” belongs to the “railway project”. Referring to the encryption / decryption key storage unit 35 illustrated in FIG. 10, it can be seen that there is a decryption key “ABC” corresponding to “railway project”.

  The encryption / decryption unit 39 obtains the decryption key from the encryption / decryption key storage unit 35, decrypts the encrypted file based on the decryption key, and passes the decrypted file to the file reference / update unit 38 ( S12-4).

  The file reference / update unit 38 uses the document creation tool function to display the decrypted file content on the display device of the information processing terminal 3 (S12-5). Here, an example of the document display screen is shown in FIG. FIG. 16 shows an example in which the decrypted file is displayed on the display device using the document creation tool function of the file reference / update unit 38.

  As described above, in the information security system 1 of the present embodiment, the user is permitted to decrypt files belonging to the group authenticated by the authentication server 2. For example, when the “patent specification” illustrated in FIG. 15A is selected in the process of S12-2, the group to which the “patent specification” belongs is a “patent group”. In the process, even when trying to acquire the decryption key corresponding to “patent group” from the encryption / decryption key storage unit 35 illustrated in FIG. 10, the decryption key related to “patent group” is not stored, and the file reference / The update process ends. Therefore, the user cannot perform file operations on the “patent specification”. That is, the user is permitted to perform file operations only on files belonging to the “railway group”.

  In addition, when the user makes some changes to the content of the “railway project plan” illustrated in FIG. 16 and updates the “railway project plan” file, the processes of S12-1 to S12-5 are performed again. Will be executed.

  That is, when the user gives an instruction to update the “railway project plan” (S12-1), the file reference / update unit 38 activates the file management unit 34. Then, the file management unit 34 acquires a group name by referring to the file attribute information storage unit 32 to which group the “railway project plan” belongs (S12-2). Next, the encryption / decryption unit 39 acquires an encryption key corresponding to the group to which the group belongs, referring to the encryption / decryption key storage unit 35 (S12-3 OK), and based on the acquired encryption key, the updated key The “railway project plan” is encrypted (S12-4). Finally, the file management unit 34 saves the updated “railway project plan” in the file storage unit 33 (S12-5).

  Thus, in the information security system 1 of the present embodiment, the user is permitted to encrypt only the files belonging to the group that has been previously authenticated by the authentication server 2.

  Next, a third process for monitoring the connection status between the information processing terminal 3 and the authentication server 2 will be described.

  FIG. 17 is a flowchart showing connection status monitoring processing, which is the third processing of the information security system 1 in the present embodiment.

  After the user authentication is performed in the first process, the connection between the information processing terminal 3 and the authentication server 2 is continued until the user is logged out. The third process is started when the user authentication is successful in the first process and the first process is completed.

  When the third process is started, the connection status monitoring unit 40 is activated, and the connection state between the information processing terminal 3 and the authentication server 2 is monitored. For example, when the user selects the logout button on the login screen illustrated in FIG. 11A (YES in S17-1), the connection status monitoring unit 40 indicates that the user with the user identifier “AAA” is assigned to the group “railway project”. It is no longer necessary to perform a file operation on the file to which it belongs, that is, it is determined that the user has logged out. Is deleted (S17-2). In this embodiment, the record related to the “railway project” is deleted from the encryption / decryption key storage unit 35, and there is no record stored in the encryption / decryption key storage unit 35 illustrated in FIG. . Furthermore, “logged in” stored in the login presence / absence field corresponding to the user identifier “AAA” and the group “railway project” illustrated in FIG. 8 is updated with a blank. Even if the second process is executed in this state, the decryption key or the encryption key cannot be obtained from the encryption / decryption key storage unit 35, and the encrypted file stored in the file storage unit 33 is decrypted. It is not possible to encrypt or save the file being used. As described above, if the information processing terminal 3 and the authentication server 2 are not connected, the file cannot be decrypted or encrypted.

  Further, the connection status monitoring unit 40 cannot refer to or update the file belonging to the logged out group after deleting the record corresponding to the logged out group from the encryption / decryption key storage unit 35 in the process of S17-2. Then, the file reference / update unit 38 is requested to stop the document creation tool function (S17-3). That is, when the logout button on the login screen illustrated in FIG. 11A is selected, the document display screen illustrated in FIG. 16 is forcibly terminated.

  In addition, the connection status monitoring unit 40 of this embodiment continuously monitors the connection with the authentication server 2. That is, the login presence / absence field of the user management database 22 is continuously monitored. It is determined whether or not “logged in” is stored in the login presence / absence field of the user management database 22 corresponding to the user identifier and group name output on the login screen illustrated in FIG. If stored, the user having this user identifier is regarded as being connected to the authentication server 2 (NO in S17-1), and the process of S17-1 is continued until it is determined that the connection is not made. If it is not stored, it is determined that the connection is not made, that is, the file is used even though the connection with the authentication server 2 is disconnected, that is, the file is used illegally (S17). -1 YES), S17-2 and S17-3 are executed. Furthermore, when the information processing terminal 3 is not physically connected to the network 4, the connection status monitoring unit 40 cannot refer to the user management database 22 of the authentication server 2. Also in this case, it is determined that the connection is disconnected (S17-1 YES), and the processes of S17-2 and S17-3 are executed.

  For example, it is assumed that a certain user uses the information processing terminal 3 to succeed in user authentication, decrypts an encrypted file, and refers to the decrypted file using a document creation tool function. It is assumed that the user forgets to log out while referring to the file, leaves, and the information processing terminal 3 is stolen while the user is away. With the conventional information processing terminal 3, the file being used by such a document creation tool function could be used illegally. However, in this embodiment, when the information processing terminal 3 is connected to a wired LAN and is physically disconnected from the LAN and stolen, the connection status monitoring is performed in the processing of S17-1 in FIG. The unit 40 cannot connect to the authentication server 2, and the processes of S17-2 and S17-3 are executed. Therefore, unauthorized reference to the file can be prevented. The information processing terminal 3 connected to the wireless LAN can be stolen without being physically disconnected from the LAN. In such a case, the user who has stolen the information processing terminal 3 uses the other information processing terminal 3 to connect to the authentication server 2 and blanks the login presence / absence field corresponding to the user identifier of the user management database 22. Update with. That is, it is assumed that the user has logged off from the authentication server 2. In this way, when the connection status monitoring unit 40 of the stolen information processing terminal 3 executes the process of S17-1 in FIG. 17 and refers to the login presence / absence field in the user management database 22 of the authentication server 2, the login is performed. You can recognize that the information has been deleted. Accordingly, it is assumed that an illegal file is being used, and the processes of S17-2 and S17-3 are executed. In other words, unauthorized use of the file can be prevented.

  As described above, in this embodiment, when authenticated by the authentication server 2, the connection status with the authentication server 2 is continuously checked, and if it is determined that the connection is not established, the file is decrypted. Alternatively, the file that is already in use is forcibly terminated so that the file cannot be manipulated such that the encryption cannot be performed and the file is referenced or updated using the document creation tool function. Therefore, even if the information processing terminal 3 is stolen while the user is logged in to the authentication server 2, unauthorized file reference and update by a third party can be prevented.

  As described above, in this embodiment, the file creation tool function cannot be used to refer to or update a file when the connection between the information processing terminal 3 and the authentication server 2 is disconnected. ing. Further, only when the connection between the information processing terminal 3 and the authentication server 2 is continued, decryption and encryption of the file are permitted. Therefore, even if the information processing terminal 3 is stolen while the user is logged in to the authentication server 2, unauthorized file reference and update by a third party can be prevented.

  Here, the file as described above is a text file, the document creation tool function is a Microsoft® memo pad (memo pad), and the text file is being used by the memo pad. Even if the text file is deleted when it is determined that the connection is not established, the contents of the text file in use are still displayed on the memo pad even if the text file in use is deleted. If the information processing terminal 3 is stolen while using the text file, unauthorized file reference by a third party cannot be prevented. Therefore, as described above, the user cannot refer to or update the file using the document creation tool function at the timing when the connection between the information processing terminal 3 and the authentication server 2 is disconnected. Even if the information processing terminal 3 is stolen while logging in to the authentication server 2, it is possible to prevent unauthorized file reference and update by a third party, which is effective in ensuring security.

  The document creation tool function of this embodiment can also prohibit copying the contents of the referenced file to a temporary storage unit such as a clipboard. For example, the contents of the “railway project plan” illustrated in FIG. 16 can be copied and stored in the temporary storage area included in the information processing terminal 3. In this way, it is possible to prevent the contents of the file from being diverted to another file. In this case, whether or not copying is possible can be set for each file, and the document creation tool function appropriately determines whether or not copying is possible according to the setting.

The following additional notes are further disclosed with respect to the embodiment including the above examples.
(Appendix 1) An information processing apparatus configured to be connectable to a monitoring server via a network,
A connection status monitoring unit for determining a connection status with the monitoring server by transmitting and receiving connection information with the monitoring server;
An information availability determination unit that determines availability of information being used according to the connection status;
An information processing apparatus comprising:
(Appendix 2) An information processing apparatus configured to be connectable to a monitoring server via a network,
A connection status monitoring unit for determining a connection status with the monitoring server by transmitting and receiving connection information with the monitoring server;
When it is determined that the connection with the monitoring server is established, the use of the information is permitted. When it is determined that the connection with the monitoring server is not established, the permitted information is being used. If there is an information availability determination unit that prohibits the use of the information,
An information processing apparatus comprising:
(Supplementary Note 3) An information processing apparatus configured to be connectable to a monitoring server via a network,
A connection status monitoring unit for determining a connection status with the monitoring server by transmitting and receiving connection information with the monitoring server;
When it is determined that the connection with the monitoring server is made, the information is encrypted or decrypted to enable the use of the information, and when it is determined that the connection with the monitoring server is not made, If the encrypted or decrypted information is in use, an information availability determination unit that prohibits the use of the information;
An information processing apparatus comprising:
(Supplementary Note 4) A method of using information in an information processing apparatus configured to be connectable to a monitoring server via a network,
Determining the connection status with the monitoring server by transmitting and receiving connection information to and from the monitoring server;
When it is determined that the connection with the monitoring server is established, the use of the information is permitted. When it is determined that the connection with the monitoring server is not established, the permitted information is being used. If so, a step that prohibits the use of the information;
A method of using information in an information processing apparatus characterized by executing
(Supplementary Note 5) An information security system in which a monitoring server and an information processing terminal are connected to a network,
The monitoring server is
A connection information transmission / reception unit for transmitting / receiving connection information to / from the information processing terminal;
A connection request receiving unit that receives a connection request from the information processing terminal;
The information processing terminal
A connection information transmission / reception unit for transmitting / receiving connection information to / from the monitoring server;
A connection request unit for sending a connection request to the monitoring server;
A connection status monitoring unit for determining a connection status with the monitoring server based on the status of transmission / reception of the connection information;
When it is determined that the connection status monitoring unit is connected to the monitoring server, an information use unit that permits encryption or decryption of information and use of the information;
When the connection status monitoring unit determines that the connection with the monitoring server is not established, the information is prohibited from being encrypted or decrypted, and the information permitted to be used by the information using unit is being used. If so, an information usage restriction unit that prohibits the use of the information,
An information security system characterized by comprising
(Supplementary Note 6) The monitoring server further includes a key storage unit that stores a decryption key or an encryption key;
A key transmission unit that transmits the decryption key or the encryption key stored in the key storage unit to the information processing terminal determined to be connectable by the connection request reception unit;
The information processing terminal further includes a key temporary storage unit that temporarily stores a decryption key or an encryption key received from the monitoring server,
The information utilization unit refers to the key temporary storage unit, acquires a decryption key or an encryption key, decrypts or encrypts the information based on the decryption key or the encryption key,
The information use restriction unit is configured to prevent the information from being decrypted or encrypted by deleting the decryption key or the encryption key stored in the key temporary storage unit. Information security system.
(Supplementary Note 7) The monitoring server includes a connection status storage unit that stores a connection status of the information processing terminal,
The connection status storage unit stores a connection status for each identifier or user identifier of the information processing terminal,
When the connection request receiving unit determines that connection is possible, the connection status storage unit stores a connection status corresponding to the identifier of the information processing terminal or the user identifier,
The connection status monitoring unit refers to the connection status storage unit, and determines that the connection with the monitoring server is not established unless the connection status corresponding to the identifier of the information processing terminal or the identifier of the user is stored. The information security system according to appendix 5, characterized by:
(Appendix 8) The information is classified according to the type of the information,
The key storage unit stores the decryption key or encryption key for each type of the classified information,
The temporary key storage unit temporarily stores the decryption key or the encryption key for each type of the information,
The information security system according to appendix 6, wherein the information utilization unit acquires a decryption key or an encryption key corresponding to a type of information to be decrypted or encrypted from the key temporary storage unit.

It is a whole lineblock diagram showing an outline of an information security system. It is a figure which shows the hardware structural example of an authentication server. It is a figure which shows the structure of an authentication server. It is a figure which shows the structure of an information processing terminal. It is a figure which shows the structure of a file server. It is a flowchart of the 1st process of an information security system. It is a figure which shows the example of a display of a user authentication screen. It is a figure which shows the example of a record structure of a user management database. It is a figure which shows the example of a record structure of an encryption / decryption key database. It is a figure which shows the example of a record structure of an encryption / decryption key memory | storage part. It is a figure which shows the example of a display of a login screen. It is a flowchart of the 2nd process of an information security system. It is a figure which shows the example of a record structure of a file management information storage part (information processing terminal). It is a figure which shows the example of a record structure of a file management information storage part (file server). It is a figure which shows the example of a display of a document list screen. It is a figure which shows the example of a display of a document display screen. It is a flowchart of the 3rd process of an information security system.

Explanation of symbols

1 Information security system 2 Authentication server (monitoring server)
3. Information processing terminal (information processing device)
4 Network 5 File Server 22 User Management Database 23 Encryption / Decryption Key Database 25 Encryption / Decryption Key Acquisition Unit 24 User Authentication Unit 35 Encryption / Decryption Key Storage Unit 36 User Authentication Request Unit 38 File Reference / Update Unit (Usability Determination Unit)
39 Encryption / Decryption Unit (Usability Determination Unit)
40 Connection status monitoring unit

Claims (3)

An information processing apparatus that controls output of first information stored in an information storage unit,
An authentication requesting unit that transmits the second information for authentication of the user input from the user to the server;
A key storage unit;
When user authentication using the second information by the server is successful, a key storage unit that receives a decryption key from the server and stores the decryption key in the key storage unit;
A decryption unit for decrypting the first information stored in the information storage unit with a decryption key stored in the key storage unit;
An information output unit that outputs the first information decoded by the decoding unit ;
The connection status between the information processing device and the server is continuously monitored, and if the connection between the information processing device and the server is disconnected, the information output unit forcibly outputs the first information A connection status monitoring unit that terminates and deletes the decryption key stored in the key storage unit ;
An information processing apparatus comprising: The first information is stored in the information storage unit in association with attribute information,
The second information further includes attribute information of the user input from the user,
When the user authentication using the second information by the server is successful, the key storage unit receives a decryption key corresponding to the attribute information of the user from the server, and receives the decryption key and the user Is stored in the key storage unit in association with the attribute information,
When the attribute information of the first information stored in the information storage unit is stored as the user attribute information in the key storage unit, the decryption unit associates the key information with the attribute information. the information processing apparatus according to claim 1, wherein the decoding key stored in the storage unit, wherein the decoding the first information. An information processing apparatus that controls output of the first information stored in the information storage unit,
Sends the second information for authentication of the user input from the user to the server,
When the user authentication using the second information by the server is successful, the decryption key is received from the server and stored in the key storage unit,
Decrypting the first information stored in the information storage unit with the decryption key stored in the key storage unit ;
Outputting the decrypted first information;
Continuously monitors the connection status between the information processing apparatus and the server, wherein when the connection of the information processing apparatus and the server is disconnected, the addition to kill the output of the first information An information output control method , comprising: deleting the decryption key stored in a key storage unit .