JP2010250405A - Information apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure validity of user authentication information by confirming that no injustice such as falsification is present in the user authentication information used for authentication processing. <P>SOLUTION: A PLC (Programmable Logic Controller) 200 holds the user authentication information for performing the authentication processing to an access request to protection assets of a protection asset apparatus 300. The protection asset apparatus 300 holds validity confirmation information that is a hash value of regular user authentication information by which a regular user is indicated. There is a possibility that the user authentication information of the PLC 200 is unauthorizedly rewritten. Accordingly, the protection asset apparatus 300 transmits a random number to the PLC 200 each time the PLC 200 starts by power ON, applies the random number to the validity confirmation information that is the hash value of the user authentication information of the PLC 200, makes a hash value of the validity confirmation value be generated, applies the random number to the validity confirmation information held by the protection asset apparatus 300, generates a hash value of the validity confirmation information, compares it with the hash value of the validity confirmation information of the PLC 200, and decides whether or not the user authentication information of the PLC 200 accords with the regular user authentication information. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technique for verifying validity of user authentication information for user authentication, and more particularly, to a technique for confirming validity of user authentication information in an FA (Factory Automation) system.

In general, in an information system, when a client system receives content from a content providing server, the user of the client system authenticates itself with a user name and password to the authentication server to prove that the user is a legitimate user. Upon receiving authentication of the user, the certificate is received from the authentication server, and the received certificate is added to the content access request and transmitted to the content providing server. The content providing server sends the received certificate to the authentication server. Make an inquiry to confirm that it is an access request from an authorized user.
In addition, the content providing server performs device authentication using information for identifying the authentication server (for example, a domain name and a serial number) in order to confirm the validity of the authentication server, and the authentication server is connected to the correct device (connected The device is good).

  As a technique related to the present invention, there is a technique described in Patent Document 1.

In addition, an authentication server that stores user authentication information and performs authentication processing in an information system generally limits users who can access the authentication server in a keyed room.
For example, according to the standard for measures against unauthorized computer access in [Ministry of International Trade and Industry Notification No. 362], in equipment management, “a device that stores important information or performs important processing can only be entered by authorized personnel. There is a description of "Installation at the place and strict management".

JP 2006-119769 A

In this way, when the content providing server having the protected asset confirms the validity of the authentication server, information (domain name, serial number, etc.) for identifying the authentication server registered in advance in the content providing server is used. Although device authentication is performed to confirm whether the connection destination server is a server that can be connected, the validity of the user authentication information stored in the authentication server has not been confirmed.
Unlike the authentication server of the information system, the FA system normally does not restrict the users who can be physically accessed by storing the authentication server (PLC: Programmable Logic Controller) in a keyed room. The memory that stores the user authentication information inside the authentication server (PLC) is removed by the user who has held it, and is replaced with another memory in which fake user authentication information is written, resulting in unauthorized access (information leakage, etc.) There is a problem that it may be done.
For this reason, in the FA system, it is necessary to check the validity of the user authentication information.

  The present invention has been made in view of the above-mentioned problems, and is mainly intended to ensure the validity of user authentication information by confirming that the user authentication information used for the authentication processing is free from tampering or the like. Objective.

The information equipment according to the present invention is
An authentication device that holds user authentication information and performs authentication processing for an access request to the protection target information using the held user authentication information, and is a user authentication information of a regular user who has an access right to the protection target information Is connected to the authentication device that is the default user authentication information,
A protection target information storage unit for storing the protection target information;
A verification information storage unit that stores regular user authentication information or information generated from at least part of the regular user authentication information as verification information;
A communication processing unit that receives from the authentication device as verification information held user authentication information held by the authentication device or information generated from at least part of the held user authentication information when the authentication device is activated; ,
When verification information is received by the communication processing unit, verification information and verification target information are collated, and whether or not the retained user authentication information held by the authentication device matches the regular user authentication information And a user authentication information verification unit for determining whether or not.

  According to the present invention, when the authentication device is activated, the verification information based on the held user authentication information held by the authentication device is compared with the verification information based on the regular user authentication information. Since the validity of the retained user authentication information is ensured by confirming that it matches the legitimate user authentication information without being tampered with, etc., the situation where unauthorized access occurs due to authentication processing based on unauthorized user authentication information It can be avoided.

FIG. 3 is a diagram illustrating an example of a system configuration according to the first embodiment. FIG. 3 is a diagram illustrating a configuration example of an engineering environment PC according to the first embodiment. FIG. 3 shows a configuration example of a PLC according to the first embodiment. The figure which shows the structural example of the protected asset apparatus which concerns on Embodiment 1. FIG. The flowchart figure which shows the write-in process of the protection asset which concerns on Embodiment 1. FIG. FIG. 3 is a flowchart showing validity confirmation processing according to the first embodiment. FIG. 5 shows a configuration example of a PLC according to the second embodiment. The figure which shows the structural example of the protected asset apparatus which concerns on Embodiment 2. FIG. FIG. 6 shows a configuration example of a PLC according to the third embodiment. The figure which shows the structural example of the protected asset apparatus which concerns on Embodiment 3. FIG.

Embodiment 1 FIG.
In the present embodiment, when a protected asset device having a protected asset is accessed from the engineering environment between various devices constituting the FA system and an engineering environment for setting a protected asset such as a control program or parameter for the device. Next, a mechanism for confirming the validity of user authentication information used when confirming whether an access request is received from a regular user will be described.
In other words, the main purpose of the present embodiment is that when an access request (write / read) from the engineering environment is received for a protected asset such as a control program or parameter stored in the FA device in the FA system, This is to realize the validity check function of authentication information that confirms the request from the user, and the user authentication information (user name / password) stored in the authentication server used for the online user authentication is rewritten illegally. Validity confirmation that it is not the fake user authentication information is generated at the initial processing of the FA device to generate a validation flag, and when requesting access to protected assets, the validation flag is checked to validate the user authentication information. Validity of authentication information that can prevent unauthorized access to protected assets by confirming And to provide a verification device and identification method.

  Here, online user authentication refers to a case where an authentication server (PLC) reads from a regular user when a protected asset device such as a control program or parameter is requested from the engineering environment to read / write (update) the protected asset. It is to confirm whether it is a write request based on the user name and password.

FIG. 1 shows a system configuration example of the FA system according to the present embodiment.
In FIG. 1, an engineering environment PC 100 is a PC (Personal Computer) for setting protected assets such as a control program and parameters for devices constituting the FA system.
When there is a request to access the protected asset held by the protected asset device 300, the PLC 200 performs an authentication process using the held user authentication information. The PLC 200 is an example of an authentication device.
The protected asset device 300 holds protected assets (protection target information) such as control programs and parameters, and when receiving an access request from the PCL 200, reads and writes the protected asset according to the access request. The protected asset device 300 is an example of an information device.

  Next, with reference to FIG. 1, the outline | summary of operation | movement of the engineering environment PC100, PLC200, and protected asset apparatus 300 which concerns on this Embodiment is demonstrated.

The engineering environment PC 100 holds regular user authentication information, which is authentication information of a regular user who has access authority to the protected asset of the protected asset device 300.
Further, the PLC 200 holds user authentication information for performing an authentication process in response to an access request to the protected asset of the protected asset device 300. The initial user authentication information of the PLC 200 is regular user authentication information. However, as described above, the user authentication information of the PLC 200 may be illegally rewritten. Therefore, each time the PLC 200 is activated when the power is turned on, the protected asset device 300 collates the verified information based on the held user authentication information held by the PLC 200 with the verification information based on the regular user authentication information, and It is determined whether the held user authentication information matches the regular user authentication information.
The protected asset device 300 stores verification information based on authorized user authentication information.
Hereinafter, as an example of the verification information, the validation information obtained by performing the hash operation on the password of the user having the Administrator authority among the regular user authentication information will be described. The verification information is the regular user authentication information. It may be itself.
The validity confirmation information (verification information) is stored in an area that cannot be accessed even when the engineering environment PC 100 is used, and the user cannot see the validity confirmation information or set any value.

When the PLC 200 is activated when the power is turned on, the protected asset device 300 that detects activation of the PLC 200 generates a random number and transmits the generated random number to the PLC 200.
In the PLC 200, validity confirmation information (confirmation information) is generated based on the retained user authentication information.
This validity confirmation information is a hash value obtained by performing a hash operation on a password of a user having Administrator authority in the held user authentication information.
Furthermore, the PLC 200 performs a hash operation on the validation information using the random number received from the protected asset device 300, generates a hash value (verification information) of the validation information, and hashes the validation information. The value is transmitted to the protected asset device 300.

The protected asset device 300 performs a hash operation using the random number transmitted to the PLC 200 on the validation information stored in itself, and generates a hash value of the validation information of itself.
When the hash value of the validation information is received from the PLC 200, the hash value of the validation information from the PLC 200 is compared with the hash value of its own validation information to determine whether or not they match. To do. If the two match, the protected asset device 300 determines that the held user authentication information held by the PLC 200 matches the regular user authentication information, and permits the PLC 200 to perform authentication processing using the held user authentication information. On the other hand, when the two do not match, the held user authentication information held by the PLC 200 does not match the regular user authentication information, and there is a possibility of falsification. For this reason, the protected asset device 300 rejects the access request even when an authentication process is performed by the PLC 200 and an access request is transmitted.

In the case where the verification information is the regular user authentication information itself in the protected asset device 300, the protected asset device 300 generates a random number by starting the PLC 200, transmits the generated random number to the PLC 200, and uses the random number. The hash value of the regular user authentication information is calculated. In the PLC 200, a random value from the protected asset device 300 is applied to the retained user authentication information to generate a hash value (verified information) of the retained user authentication information, and the hash value of the retained user authentication information is stored in the protected asset device 300. Send.
Then, in the protected asset device 300, the hash value of the retained user authentication information received from the PLC 200 is compared with the hash value of the authorized user authentication information, and whether or not the retained user authentication information of the PLC 200 matches the authorized user authentication information. Determine whether.

Next, configuration examples of the engineering environment PC 100, the PLC 200, and the protected asset device 300 will be described with reference to FIG. 2, FIG. 3, and FIG.
First, a configuration example of the engineering environment PC 100 will be described with reference to FIG.

In FIG. 2, an input unit 101 inputs a control program and parameter settings for an FA device designated by a user, a user name, a password, and the like at the time of online user authentication through a keyboard, a mouse, and the like.
The protected asset storage unit 102 stores a protected asset to be written to the protected asset device 300.
The protected asset access processing unit 103 performs access processing to the protected asset of the protected asset device 300. More specifically, the protected asset input from the user by the input unit 101 is stored in the protected asset storage unit 102, the protected asset stored in the protected asset storage unit 102 is read, and the protected asset is read through the communication processing unit 104. A process of writing the protected asset in the device 300 is performed. Further, based on an instruction from the user, a process of reading the protected asset stored in the protected asset device 300 through the communication processing unit 104 is performed.
The communication processing unit 104 exchanges data such as user authentication information and protected assets with the PLC 200.
The user authentication information storage unit 105 stores user authentication information (user name and password) for confirming that the protected asset access processing unit 103 is an access request from an authorized user when accessing the protected asset of the protected asset device 300. Is stored.
The online user authentication processing unit 106 transmits the user authentication information input from the user by the input unit 101 to the PLC 200 through the communication processing unit 104 when the protected asset access processing unit 103 accesses the protected asset of the protected asset device 300.

  Next, a configuration example of the PLC 200 will be described with reference to FIG.

In FIG. 3, the communication processing unit 204 performs communication between the engineering environment PC 100 and the protected asset device 300.
The user authentication information storage unit 205 stores user authentication information (user name and password) used when performing an authentication process for an access request from the engineering environment PC 100. As described above, the user authentication information stored as an initial value in the user authentication information storage unit 205 is regular user authentication information indicating the user name and password of a regular user, but the user authentication information is altered by an illegal act. there is a possibility.
The online user authentication processing unit 206 compares the user name and password included in the access request from the engineering environment PC 100 with the user authentication information stored in the user authentication information storage unit 205 to determine whether the access request is from a legitimate user. Perform the authentication process.
The initial processing unit 207 performs initial setting of the PLC 200 itself and parameter setting for the protected asset device 300 connected to the network (bus connection) when the power of the PLC 200 is turned on.
The random number generation processing unit 208 generates a random number for generating a session ID.
When the online user authentication processing unit 206 succeeds in online user authentication, the session management unit 209 proves that the user is an authorized user without performing online user authentication each time a subsequent access request is made. Generate / manage session IDs.
The validity confirmation information generation unit 210 generates validity confirmation information for confirming the validity of the user authentication information from the password information of all users having administrator authority stored in the user authentication information storage unit 205.
The validity check hash generation processing unit 211 is executed in conjunction with the parameter setting to the protected asset device 300 by the initial processing unit 207, and protects the validity check information generated by the validity check information generation unit 210. A hash value of validation information is generated by applying a random number supplied from the asset device 300.

  Next, a configuration example of the protected asset device 300 will be described with reference to FIG.

In FIG. 4, the protected asset storage unit 302 stores protected assets (protection target information) such as control programs and parameters generated by the engineering environment PC 100. The protected asset storage unit 302 is an example of a protection target information storage unit.
The protected asset access processing unit 303 reads and writes the protected asset stored in the protected asset storage unit 302 in accordance with the access request after the authentication process is performed by the PLC 200.
The communication processing unit 304 performs communication with the PLC 200.

The random number generation processing unit 308 generates a random number used for the hash calculation for the validity check information in conjunction with the parameter setting to the protected asset device 300 by the initial processing unit 207 of the PLC 200 when the PLC 200 is activated by turning on the power. To do. The random number generation processing unit 308 is an example of a user authentication information verification unit.
The validity confirmation information storage unit 312 stores validity confirmation information that is a hash value of the authorized user authentication information. The validity confirmation information storage unit 312 is an example of a verification information storage unit. The validation information storage unit 312 writes the validation information in an area that cannot be accessed using the engineering environment PC 100, and the user can see the validation information or set an arbitrary value. I can't do that either.

The validity confirmation hash generation processing unit 311 applies the random number generated by the random number generation processing unit 308 to the validity confirmation information stored in the validity confirmation information storage unit 312 to hash the validity confirmation information. Generate a value. The validity confirmation hash generation processing unit 311 is an example of a user authentication information verification unit.
The validity confirmation processing unit 313 is a user authentication information storage unit 205 that is stored in the PLC 200 in conjunction with the parameter setting for the protected asset device 300 by the initial processing unit 207 of the PLC 200 when the PLC 200 is activated by turning on the power. Check the validity of the user authentication information. More specifically, the hash value of the validation information generated by the PLC 200 and the hash value of the validation information generated by the validation hash generation processing unit 311 are compared, and user authentication in the PLC 200 is performed. It is determined whether the information matches the regular user authentication information. The validity confirmation processing unit 313 is an example of a user authentication information verification unit.

The validity check flag storage unit 314 stores a validity check flag indicating True if the validity check is successful based on the result of the validity check processing unit 313, and indicating False if the validity check is failed.
The validity confirmation flag processing unit 315 sets a validity confirmation flag in the validity confirmation flag storage unit 314 based on the result of the validity confirmation processing unit 313, and receives an access request from the engineering environment PC 100 from the PLC 200. In this case, the access request is permitted (in the case of True) / prohibited (in the case of False) according to the validity confirmation flag stored in the validity confirmation flag storage unit 314. The validity check flag processing unit 315 is an example of an authentication control unit.

  In addition, the engineering environment PC 100, the PLC 200, and the protected asset device 300 may be configured with respective components by hardware, a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory). The CPU executes a program that includes a magnetic disk device or the like and realizes a function denoted as “unit” using a RAM, a ROM, a magnetic disk, or the like, so that the engineering environment PC 100, the PLC 200, and the protected asset device 300 Processing may be performed.

Next, an operation example according to the present embodiment will be described with reference to FIGS.
FIG. 5 is a processing flow when writing protected assets such as a control program and parameters from the engineering environment PC 100 to the protected asset device 300.
FIG. 6 is a flowchart of validity checking executed when the device is turned on.
5 illustrates the process of writing the protected asset, but when the protected asset is read from the protected asset device 300, the process is performed according to the flow of FIG. When reading a protected asset, “write” in S513 and S516 may be read as “read”.

  First, a procedure for creating a protected asset in the engineering environment will be described.

The user creates a protected asset such as a control program and parameters for the protected asset device 300 using the input unit 101 of the engineering environment PC 100, and stores the created protected asset in the protected asset storage unit 102 using the protected asset access processing unit 103. To do.
Further, the user inputs user authentication information (user name and password) for permitting only authorized user access to the protected asset using the input unit 101, and stores it in the user authentication information storage unit 105. .

Next, a procedure for writing the protected asset created on the engineering environment PC 100 to the protected asset device 300 will be described with reference to FIG.
The user connects the engineering environment PC 100 and the PLC 200 to the network using a USB (Universal Serial Bus) cable or the like.
The PLC 200 and the protected asset device 300 are used by being mounted on a basic base (board), for example, and are connected by a bus in the board.
Data communication between the engineering environment PC 100 and the PLC 200 and between the PLC 200 and the protected asset device 300 is performed using the communication processing units 104, 204, and 304.
When the user instructs to write the control program and parameters stored in the protected asset storage unit 102 in the engineering environment PC 100 to the protected asset device 300 using the input unit 101, the communication processing unit 104 connects to the protected asset device 300. A confirmation request is transmitted (S501).
The connection confirmation request includes information such as the model name of the engineering environment PC 100 and the protected asset device 300 that can be used to authenticate the engineering environment PC 100.

The connection confirmation request reaches the communication processing unit 304 of the protected asset device 300 via the communication processing unit 204 of the PLC 200.
The communication processing unit 304 that has received the connection confirmation request performs device authentication using information included in the connection confirmation information (for example, the model name of the engineering environment PC 100), and a device to which the connection confirmation request transmission source may connect. Whether or not (S502).
For example, the protected asset device 300 holds the type name of the device that may be connected in a predetermined storage area, and the communication processing unit 304 transmits the type of the device that is the source of the connection confirmation request included in the connection confirmation request. The name is compared with the stored type name.
If it is not a device that can be connected (NO in S502), it is determined as a connection NG, and the communication processing unit 304 returns an error code to the communication processing unit 104 of the engineering environment PC 100 via the communication processing unit 204 to protect it. Do not allow writing of assets.
On the other hand, in the case of a device that can be connected (YES in S502), whether the validity confirmation information is already stored in the validity confirmation information storage unit 312 when a response to the connection OK is returned to the communication processing unit 104. Confirm whether or not and return the result together.

When the communication processing unit 104 of the engineering environment PC 100 receives the connection NG error code as a response to the connection confirmation request, the communication processing unit 104 stops the write processing of the protected asset (S516).
In the case of connection OK, it is confirmed whether or not the validity confirmation information is stored in the validity confirmation information storage unit 312 of the protected asset device 300 (S503), and when the validity confirmation information is not stored (S503). In step S504, the communication processing unit 104 acquires the user authentication information from the user authentication information storage unit 105, and transmits the acquired user authentication information to the PLC 200 before executing the protected asset write process. The user authentication information is written into the user authentication information storage unit 205 (S505). This user authentication information is regular user authentication information.
In the process of writing user management information, the online user authentication processing unit 206 first writes a user having Administrator authority in the user authentication information storage unit 205.
This is to prevent unauthorized access to the protected asset by writing the user authentication information first even if the processing is interrupted due to some failure during the protected asset writing process.

Next, the validity confirmation information generation unit 210 of the PLC 200 generates validity confirmation information (S506).
The validity confirmation information is calculated by using the validity confirmation information generation unit 210 to calculate a hash value using the passwords of all users having Administrator authority written in the user authentication information storage unit 205. Confirmation information.
The validity confirmation information is transmitted from the communication processing unit 204 to the communication processing unit 304, and the validity confirmation processing unit 313 writes it in the validity confirmation information storage unit 312 (S507).

When the writing of the validation information to the validation information storage unit 312 is completed, the communication processing unit 104 requests the protected asset access processing unit 103 to read out the protected assets such as control programs and parameters from the protected asset storage unit 102. Put out.
When the communication processing unit 104 receives the protected asset read from the protected asset storage unit 102, the communication processing unit 104 transmits a request for writing the read protected asset to the protected asset storage unit 302 of the protected asset device 300 to the communication processing unit 204.
Upon receiving the protected asset write request, the communication processing unit 204 extracts the session ID added to the request, and requests the session management unit 209 to determine whether the session ID is valid or invalid.
The session management unit 209 determines whether or not the sent session ID is issued for a user who has succeeded in online user authentication based on information managed by the session management unit 209, and the result is determined by the communication processing unit 204. Return to.
When the communication processing unit 204 receives the determination result that the session ID is valid from the session management unit 209 (valid in step S509), the communication processing unit 204 transfers the write request for the protected asset to the communication processing unit 304.
When receiving the write request for the protected asset, the communication processing unit 304 extracts the protected asset data from the write request, and issues a write instruction for the protected asset to the protected asset access processing unit 303.
In response to the instruction from the communication processing unit 304, the protected asset access processing unit 303 writes the protected asset in the protected asset storage unit 302 (S513).

On the other hand, when the communication processing unit 204 receives a determination result that the session ID is invalid from the session management unit 209 (invalid in S509), a random number is used to perform online user authentication for the online user authentication processing unit 206. The online user authentication processing unit 206 requests the random number generation processing unit 208 to generate a random number, the random number generation processing unit 208 generates a random number, and returns the random number to the online user authentication processing unit 206.
When receiving the random number, the online user authentication processing unit 206 returns the random number to the communication processing unit 204 and temporarily stores the random number.

The communication processing unit 204 adds the received random number to the communication processing unit 104 and requests online user authentication.
Upon receiving the online user authentication request, the communication processing unit 104 instructs the online user authentication processing unit 106 to perform online user authentication, and passes the received random number.
The online user authentication processing unit 106 displays a login screen for the user of the engineering environment PC 100, and the user inputs a user name and password using the input unit 101.
The online user authentication processing unit 106 receives the password input using the input unit 101 and the random number sent from the communication processing unit 204 to generate a hash value using a hash function, and sends the user name and the communication processing unit 104 Returns a hash value.
The communication processing unit 104 returns a user name and a hash value in response to the online user authentication request from the communication processing unit 204.
The communication processing unit 204 receives the user name and hash value from the communication processing unit 104, and passes the received user name and hash value to the online user authentication processing unit 206.
The online user authentication processing unit 206 extracts a password from the user authentication information storage unit 205 based on the received user name, and generates a hash value by a hash function using the previously stored random number and the password as input. .
The generated hash value and the hash value received from the communication processing unit 204 are compared to confirm whether or not they match (S510).
If the hash values do not match (failed in S511), the online user authentication processing unit 206 returns an online user authentication failure to the communication processing unit 204, and the communication processing unit 204 returns an online user authentication failure to the communication processing unit 104. .
When receiving the online user authentication failure, the communication processing unit 104 requests the user to re-enter the user name / password, or requests the user to determine whether to cancel the protected asset writing process.
When the user determines to cancel the protected asset write process, the write process is stopped (S516).
When the hash values match in the online user authentication processing unit 206 (success in online user authentication processing) (success in S511), the session management unit 209 is requested to generate a session ID.
The session management unit 209 requests the random number generation processing unit 208 to generate a random number, receives the random number, for example, generates a hash value with a hash function by combining the user name and the random number input by the user at the time of online user authentication, The hash value is used as a session ID (S512).
The generated hash value is stored in the session management unit 209.
This value is used to confirm whether or not the value is issued to a regular user who has succeeded in the online user authentication process during the session ID confirmation process.
The online user authentication processing unit 206 returns the success of online user authentication and the session ID to the communication processing unit 204.
The communication processing unit 204 returns the online user authentication result and the session ID to the communication processing unit 104.
The communication processing unit 104 temporarily stores the session ID, and when the access request is next issued to the protected asset device 300, the session ID is added to the access request and transmitted to the communication processing unit 204.

Further, when the communication processing unit 104 receives a response indicating that the connection confirmation request is OK and the validity confirmation information has already been stored in the validity confirmation information storage unit 312 (registered in S504). In the same manner as described above, the protected asset is read from the protected asset storage unit 102, and a request for writing the read protected asset into the protected asset storage unit 302 is transmitted to the communication processing unit 204.
The communication processing unit 204 determines that the request is an access request to the protected asset device 300 and transfers the received request to the communication processing unit 304 of the protected asset device 300.

When the communication processing unit 304 determines that the request is a write request for protected assets, the communication processing unit 304 instructs the validity confirmation flag processing unit 315 to check the validity confirmation flag stored in the validity confirmation flag storage unit 314.
The validity check flag processing unit 315 reads the validity check flag from the validity check flag storage unit 314 (S514, S515), and permits access to the protected asset storage unit 302 when the validity check flag is True. In the case of False, a signal for prohibiting access to the protected asset storage unit 302 is returned to the communication processing unit 304.
The communication processing unit 304 returns the access permission / prohibition returned from the validity confirmation flag processing unit 315 to the communication processing unit 204.
When the communication processing unit 204 receives the access prohibition signal, the communication processing unit 104 returns an access prohibition error code to the communication processing unit 104, and the communication processing unit 104 receives the access prohibition error code and stops the protected asset writing process ( S516).
When receiving the access permission signal, the communication processing unit 204 performs the session ID confirmation process, the online user authentication process, and the protected asset write process as described above (S508 to S513).

Next, with reference to FIG. 6, the validity checking operation executed when the PLC 200 is turned on will be described.
When the power source of the PLC 200 is turned on, the initial processing unit 207 sets up itself and sets parameters and the like for a device (such as the protected asset device 300) mounted on the same basic base (S601). .
The protected asset device 300 confirms the validity of the user authentication information stored in the user authentication information storage unit 205 with the PLC 200 after processing such as parameter setting.

The communication processing unit 304 requests the validity confirmation processing unit 313 to confirm the presence / absence of validity confirmation information after the parameter setting process from the PLC 200 is completed.
The validity confirmation processing unit 313 receives a request for confirmation of the existence of validity confirmation information, confirms whether the validity confirmation information is registered in the validity confirmation information storage unit 312 (S602), and the result (unregistered) / Registered) is returned to the communication processing unit 304.
When the validity confirmation information is “registered” (registered in S603), a validity confirmation process (S605) of user authentication information is performed.

The validity confirmation process (S605) of the user authentication information is performed by the following procedure, for example.
The validity check processing unit 313 uses a random number and a valid number necessary for performing a validity check process on the validity check hash generation processing unit 311 before returning the result of the presence check of the validity check information to the communication processing unit 304. Requests the generation of a hash value for sex verification.
Upon receiving a request for random number generation, the validity checking hash generation processing unit 311 requests the random number generation processing unit 308 to generate a random number, and the random number generation processing unit 308 generates a random number to generate a validity checking hash generation processing unit. Return to 311.
Next, the validity confirmation hash generation processing unit 311 extracts the validity confirmation information stored in the validity confirmation information storage unit 312, and performs validity confirmation based on the random number received from the random number generation processing unit 308. Generate a hash value of.
The validity checking hash generation processing unit 311 returns the random number generated by the random number generation processing unit 308 and the hash value for validity checking to the validity checking processing unit 313.
The validity checking processing unit 313 returns the result of checking whether there is validity checking information and the random number received from the validity checking hash generation processing unit 311 to the communication processing unit 304, and temporarily stores the hash value for checking the validity. To do.
The communication processing unit 304 adds the random number received from the validity checking processing unit 313 to the user authentication information to the communication processing unit 204 when the result of the presence checking of the validity checking information is “registered”. Request validation of.
The communication processing unit 204 receives the validity confirmation request and instructs the validity confirmation hash generation processing unit 211 to generate a hash value for validity confirmation.
At this time, the random number received from the communication processing unit 304 is also passed to the validity checking hash generation processing unit 211.
The validity confirmation hash generation processing unit 211 instructs the validity confirmation information generation unit 210 to generate validity confirmation information.
The validation information generation unit 210 extracts passwords of all users having the Administrator authority from the user authentication information storage unit 205, generates validation information based on the extracted passwords, and generates a hash for validation The validity confirmation information generated is returned to the processing unit 211.
The validity confirmation hash generation processing unit 211 generates a hash value using a hash function based on the random number received from the communication processing unit 204 and the validity confirmation information received from the validity confirmation information generation unit 210, and performs communication processing. A hash value generated for validity confirmation is returned to the unit 204.
The communication processing unit 204 returns the received hash value to the communication processing unit 304, and the communication processing unit 304 passes the hash value to the validity confirmation processing unit 313.
The validity checking processing unit 313 compares the hash value for validity checking generated on the PLC 200 side with the hash value for validity checking temporarily stored in the validity checking processing unit 313, and communicates the result. It returns to the processing unit 304.

The communication processing unit 304 receives the comparison result of the hash value for the validity check, and if the comparison result is “match” (match in S606), the validity check flag processing unit 315 is checked with the validity check flag. The storage unit 314 is instructed to set “True”.
If the comparison result is “mismatch” (mismatch in S606), the validity confirmation flag processing unit 315 is instructed to set “False” in the validity confirmation flag storage unit 314.

On the other hand, when the communication processing unit 304 receives the confirmation result from the validity confirmation processing unit 313 and the validity confirmation information is “unregistered” (not registered in S603), the communication processing unit 304 sends the validity confirmation flag processing unit 315 to the validity confirmation flag processing unit 315. On the other hand, an instruction is given to set “True” in the validity check flag.
The validity confirmation flag processing unit 315 receives an instruction for setting the validity confirmation flag, and sets “True” in the validity confirmation flag storage unit 314.

In this way, the validity confirmation information generated from the password of the user having the Administrator authority, the validity of the user authentication information stored in the user authentication information storage unit 205 in conjunction with the power-on of the FA device (at the time of initial processing). In this case, it is possible to prevent unauthorized access (information leakage or information tampering) when the user is rewritten with fake user authentication information by a malicious user.
In other words, if the user authentication information in the user authentication information storage unit 205 has been tampered with, it becomes “mismatch” in the determination in S606, and therefore the value of the validity confirmation flag becomes False (S607). After that, even when there is a request for access to the protected asset, the validity confirmation flag processing unit 315 confirms the value of the validity confirmation flag (S514, S515), and the value of the validity confirmation flag is False. Access to the protected asset can be denied (S516).
On the other hand, if the user authentication information in the user authentication information storage unit 205 has not been tampered with, it is “match” in the determination in S606, and therefore the value of the validity check flag is True (S604). After that, when there is a request for access to the protected asset, the validity confirmation flag processing unit 315 confirms the value of the validity confirmation flag (S514, S515), and the value of the validity confirmation flag is True. The authentication process using the user authentication information in the user authentication information storage unit 205 is permitted to the PLC 200 (S508 to S512), and when the authentication is successful, the protected asset can be accessed (S513).

  Thus, according to the present embodiment, the protected asset device that entrusts online user authentication to the authentication server for the user authentication information stored in the authentication server supplies the validity of the user authentication information. By checking at the time of ON (initial processing), for example, even if a malicious user rewrites it with fake user authentication information, it is possible to detect the fraud when the power is turned on, and fraud from malicious users. Access (information leakage and information falsification) can be prevented.

  In the present embodiment, an example is shown in which a hash value is generated from the passwords of all users having Administrator authority from the user authentication information storage unit 205 and used as validation information. For example, Administrator is used. When a plurality of authorized users are registered, validity confirmation information is generated for each user, individually stored in the validity confirmation information storage unit 312, and validity is confirmed when the validity of the user authentication information is confirmed. If at least one of the plurality of validity confirmation information stored in the confirmation information storage unit 312 matches, it may be determined that the validity confirmation has succeeded.

As described above, in the present embodiment, whether an access request is received from a legitimate user between various devices constituting an FA (Factory Automation) system and an engineering environment for setting a protection program such as a control program and parameters for the devices. An apparatus for validating user authentication information used for online user authentication for confirming the above has been described.
More specifically, the PLC (Programmable Logic Controller) has an online user authentication function as an authentication server, and there has been an access request from the engineering environment to a protected asset device mounted on the same base (substrate) as the PLC. In this case, the device for confirming the validity of the user authentication information (user name and password) stored in the PLC when the PLC performs the online user authentication process has been described.

In the present embodiment,
An input unit for inputting an access request to a protected asset held by an engineering environment or equipment, user authentication information for indicating that the user is an authorized user at that time,
A protected asset storage unit for storing protected assets such as control programs and parameters in the equipment or engineering environment;
A protected asset access processing unit that performs read processing of the protected asset stored in the protected asset storage unit in response to an instruction from the user using the input unit and write processing of the protected asset to the protected asset storage unit;
A communication processing unit for transmitting / receiving data between the engineering environment and the PLC or between the PLC and the protected asset device and for determining the access request content from the engineering environment;
User authentication information registered in advance by the user in order to confirm that the user who has accessed when accessing the protected asset stored in the protected asset storage unit in the engineering environment or the protected asset device is a regular user. A user authentication information storage unit for storing;
The user authentication information entered by the user at the input unit and the user authentication information stored in the user authentication information storage unit in the PLC when accessing the protected asset of the protected asset device from the engineering environment. An online user authentication processing unit for confirming that they are the same in comparison;
An initial processing unit for performing initial processing for the PLC itself and setting parameters for the protected asset device via the communication processing unit when the power of the PLC is turned ON;
A random number generation processing unit that generates a random number to be used for online user authentication and validation;
A session management unit that determines whether an access request is received from a user who has been successfully authenticated in the online user authentication process between the engineering environment and the PLC, and generates and manages a session ID used in the determination;
A validation information generating unit that generates validation information based on a password of a user having Administrator authority extracted from the user authentication information stored in the user authentication information storage unit;
A validation information storage unit that transfers the validation information generated by the validation information generation unit to the protected asset device through the communication processing unit and stores it inside the device;
In order to confirm the validity of the user authentication information stored in the user authentication information storage unit, the random number generated by the random number generation processing unit in the protected asset device and the validity check generated by the validity check information generation unit A validation hash generation processing unit that generates a hash value based on validation information stored in the information or the validation information storage unit;
The hash value generated by the hash generation processing unit for validation of the PLC and the protected asset device is compared on the protected asset device side, and the validity of the user authentication information stored in the user authentication information storage unit of the PLC is confirmed. A validation processing unit to perform,
A validation flag storage unit for storing a validation flag (True / False) based on the comparison result in the validation processing unit;
Based on the comparison result in the validity check processing unit, the validity check flag is set to True (when the validity check is successful) or False (when the validity check is failed), and the validity check flag is stored in the validity check flag storage unit. Authentication with a validation flag processing unit that writes parameters to the PLC and the protected asset device in response to parameter setting processing executed in the initial processing of the PLC. An information validation device was described.

In the present embodiment,
User authentication information used for online user authentication that checks whether access requests are received from authorized users between various devices that make up the FA system and an engineering environment that sets protected assets such as control programs and parameters for those devices In the method of confirming validity,
Before performing online user authentication between the engineering environment and the PLC that is the authentication server, the protected asset device side uses password information of a user with Administrator authority to confirm the validity of the user authentication information stored in the PLC. The validation information generated based on this is compared at the initial processing of the FA device to generate a validation flag, and when requesting access to protected assets, validation of the user authentication information is performed by checking the validation flag. Explained the validation method of authentication information.

Embodiment 2. FIG.
In the present embodiment, when a change occurs in the user authentication information stored in the user authentication information storage unit 205 in the PLC 200, the change is stored in the validity confirmation information storage unit 312 in the protected asset device 300. A function for executing the update process of the validity check information according to the change of the user authentication information will be described.

FIG. 7 shows a configuration example of the PLC 200 according to the present embodiment.
In FIG. 7, a user authentication information change notification unit 216 is added as compared with the configuration shown in FIG. Other components are the same as those shown in FIG.
The user authentication information change notification unit 216 stores the validity confirmation information storage unit 312 when addition / change / deletion is performed on the user authentication information of the user having the Administrator authority stored in the user authentication information storage unit 205. The protected asset device 300 is notified that the validation information needs to be updated.

FIG. 8 shows a configuration example of the protected asset device 300 according to the present embodiment.
In FIG. 8, compared to the configuration shown in FIG. 4, a protected asset deletion instruction unit 317 and a validity check information update processing unit 318 are added. Other components are the same as those shown in FIG.
The protected asset deletion instruction unit 317 receives the deletion notification of the user authentication information from the user authentication information change notification unit 216 when deleting all the user authentication information in the user authentication information storage unit 205, and sends it to the protected asset access processing unit 303. An instruction to delete the protected asset in the protected asset storage unit 302 is issued. The protected asset deletion instruction unit 317 is an example of an information deletion unit.
The validity check information update processing unit 318 executes update processing or validity check processing of the validity check information in the validity check information storage unit 312 in response to the change notification or deletion notification from the user authentication information change notification unit 216. An instruction to delete all protected assets is issued to the instruction and protected asset deletion instruction unit 317. The validity check information update processing unit 318 is an example of a verification information update unit and an information deletion unit.

  The configuration of the engineering environment PC 100 is the same as that shown in FIG.

  Next, an operation for updating the validity check information when the user authentication information of the user having Administrator authority is added, the password is changed, or the deletion is described.

The user adds a user who has changed the user password stored in the user authentication information storage unit 105 on the engineering environment PC 100, deleted the user authentication information, and has Administrator authority using the input unit 101 of the engineering environment PC 100. An instruction to write the changed user authentication information into the PLC 200 is issued.
When receiving a user authentication information write instruction, the communication processing unit 104 issues a user authentication information write request to the communication processing unit 204 of the PLC 200.
In the following description, it is assumed that online user authentication and session ID confirmation have been completed.
Upon receiving the user authentication information write request, the communication processing unit 204 issues a write request to the user authentication information change notification unit 216.
Upon receiving a request for writing user authentication information, the user authentication information change notifying unit 216 checks whether or not the user authentication information to be updated is for a user having administrator authority, and the update target is for a user having administrator authority. If all the passwords of users having Administrator authority are extracted from the user authentication information storage unit 205, the password of the user to be updated is replaced with the changed password, and then the updated password is input to the validation information generation unit 210. Request the generation of validation information.
The validity confirmation information generation unit 210 generates a hash value by a hash function using the received updated password as input, and returns the generated hash value to the user authentication information change notification unit 216 as validity confirmation information.
When the user authentication information change notification unit 216 receives the newly generated validity check information, the user authentication information change notification unit 216 transmits a request for updating the validity check information to the communication processing unit 304 via the communication processing unit 204.

When the communication processing unit 304 receives the update request for the validity check information, the communication processing unit 304 instructs the validity check information update processing unit 318 to update the validity check information.
The validity check information update processing unit 318 replaces the validity check information currently stored in the validity check information storage unit 312 with the newly generated validity check information in response to an update processing instruction.
When the update processing of the validity check information is completed, the validity check information update processing unit 318 returns update completion to the user authentication information change notification unit 216.
As described above, the validity confirmation information update processing unit 318 corresponds to the update of the authorized user authentication information when the authorized user authentication information is updated in the engineering environment PC 100 that is the management source of the authorized user authentication information. The validity confirmation information stored in the validity confirmation information storage unit 312 is updated.

Upon receiving the update completion from the validity confirmation information update processing unit 318, the user authentication information change notification unit 216 updates the user authentication information in the user authentication information storage unit 205.
The validity confirmation information update processing unit 318 instructs the validity confirmation processing unit 313 to execute the validity confirmation processing after returning the update completion to the user authentication information change notification unit 216.
In response to the execution instruction, the validity confirmation processing unit 313 confirms the presence or absence of validity confirmation information, confirms the validity of the user authentication information, and updates the validity confirmation flag.
The validity confirmation process of the validity confirmation processing unit 313 is the process described in the first embodiment as the operation of S605 in FIG.
By performing the validity confirmation process, it can be confirmed that the validity confirmation information updated by the validity confirmation information update processing unit 318 corresponds to new user authentication information stored in the user authentication information storage unit 205. .

  According to the above procedure, even when the user authentication information is changed, the validity confirmation information can be updated together with it, and consistency can always be maintained.

Next, an operation for deleting all user authentications stored in the user authentication information storage unit 205 will be described.
When deleting all user authentication information, it is necessary to delete all protected assets first.
This is because if all the user authentication information is deleted first, the access to the protected assets cannot be restricted, and there is a risk that the control program and parameters are leaked to the outside or altered.

When the user issues an instruction to delete all user authentication information stored in the user authentication information storage unit 205 using the input unit 101 of the engineering environment PC 100, the user authentication information change notification unit 216 displays the user authentication information storage unit Before deleting the user authentication information 205, a request for deleting a protected asset is transmitted to the validity confirmation information update processing unit 318.
When the validation information update processing unit 318 receives the protected asset deletion request, it requests the protected asset deletion instruction unit 317 to delete all the protected assets stored in the protected asset storage unit 302.
When receiving the deletion request, the protected asset deletion instruction unit 317 instructs the protected asset access processing unit 303 to delete all the protected assets, and the protected asset access processing unit 303 receives the deletion request and stores it in the protected asset storage unit 302. Deletes all the protected assets such as stored control programs and parameters, and returns deletion completion.
Upon receiving the completion of deletion, the validity check information update processing unit 318 next deletes the validity check information stored in the validity check information storage unit 312.
Further, the validity confirmation flag processing unit 315 is instructed to make a request for setting “True” in the validity confirmation flag in the validity confirmation flag storage unit 314.
When the above processing is completed, the validity confirmation information update processing unit 318 returns deletion completion of all the protected assets to the user authentication information change notification unit 216.
The user authentication information change notification unit 216 deletes all user authentication information in the user authentication information storage unit 205 after receiving the deletion completion.
As a result, unauthorized access to the protected asset due to deletion of all user authentication information can be prevented.

  As described above, the validity confirmation information update processing unit 318 and the protected asset deletion instruction unit 317 are stored in the protected asset storage unit 302 when it is necessary to delete the user authentication information held by the PLC 200. Delete the protected asset, delete the protected asset, delete the validation information stored in the validation information storage unit 312, and delete the user authentication information from the PLC 200 after deleting the validation information. Instruct.

As described above, in the present embodiment,
When the password of the user having the Administrator authority stored in the user authentication information storage unit in the PLC is changed, or when a user having the Administrator authority is newly added and stored in the user authentication information storage unit A user authentication information change notification unit for notifying the protected asset device that the validation information in the validation information storage unit needs to be updated when all the user authentication information is deleted,
In response to the change notification from the user authentication information change notifying unit, the validity checking information in the validity checking information storage unit is updated, and the validity between the PLC and the protected asset device is again updated after the validity checking information is updated. A validation information update processing unit for instructing execution of the validity checking process;
Validity of authentication information provided with a protected asset deletion instruction unit that deletes the protected assets stored in the protected asset storage unit of the protected asset device when all user authentication information in the user authentication information storage unit is deleted A verification device has been described.

Embodiment 3 FIG.
In the present embodiment, the value of the counter that counts up every time an access request for user authentication information of a user having Administrator authority is received for validity confirmation of the user authentication information stored in the user authentication information storage unit 205 in the PLC 200. Explains the function that performs validation using.

FIG. 9 shows a configuration example of the PLC 200 according to the present embodiment.
In FIG. 9, compared with the configuration shown in FIG. 7, the counter processing unit 219 and the initial value setting unit 220 are added, while the validity confirmation information generating unit 210 is removed. The other components are the same as those shown in FIG.
The counter processing unit 219 requests access to user authentication information of a user having the Administrator authority stored in the user authentication information storage unit 205 as information known only to both the PLC 200 serving as an authentication server and the protected asset device 300 ( Every time receiving (addition / change / deletion), the counter value is counted up.
In other words, the counter processing unit 219 updates the number of regular user authentication information in the engineering environment PC 100 every time the engineering user PC 100 that is the management source of the regular user authentication information is updated (added / changed / deleted). Count.
Note that the counter processing unit 219 writes the count value in an area that cannot be accessed using the engineering environment PC 100, and the user cannot see the count value or set an arbitrary value.
The counter processing unit 219 clears the count value when the user authentication information in the user authentication information storage unit 205 is updated asynchronously with the update of the regular user authentication information in the engineering environment PC 100.
The initial value setting unit 220 generates an initial value when the user authentication information is written in the user authentication information storage unit 205 for the first time, and sets the initial value in the counter processing unit 219.
Note that the initial value set by the initial value setting unit 220 is a random value.

FIG. 10 shows a configuration example of the protected asset device 300 according to the present embodiment.
In FIG. 10, compared with the configuration shown in FIG. 3, a counter processing unit 319 and an initial value setting unit 320 are added, while the validity confirmation information storage unit 312 is omitted. The other components are the same as those shown in FIG.
Similarly to the counter processing unit 219, the counter processing unit 319 calculates the number of updates of the regular user authentication information in the engineering environment PC 100 each time the regular user authentication information is updated in the engineering environment PC 100 that is the management source of the regular user authentication information. Count.
Note that the counter processing unit 319 writes the count value in an area that cannot be accessed even using the engineering environment PC 100, and the user cannot see the count value or set an arbitrary value.
The initial value setting unit 320 also sets a random value that is the same value as the initial value set by the initial value setting unit 220 of the PLC 200 as the initial value of the count by the counter processing unit 319.

  The configuration of the engineering environment PC 100 is the same as that shown in FIG.

Next, an operation for setting an initial value for the counter processing units 219 and 319 will be described.
When the user writes the protected asset in the protected asset storage unit 302 of the protected asset device 300 using the input unit 101 of the engineering environment PC 100, the user authentication information is not registered in the user authentication information storage unit 205 of the PLC 200. In this case, the user authentication information is written first before the protected asset is written.
After the completion of the user authentication information writing process, the communication processing unit 204 extracts the number of users having Administrator authority from the user authentication information written in the user authentication information storage unit 205, and stores the counter value in the initial value setting unit 220. Instructs the initial value setting.
At this time, the registration number of users having Administrator authority and the time stamp when the user authentication information is written are passed.
The initial value setting unit 220 receives an instruction to set an initial value, and generates a numerical value (random number or hash value) having randomness based on the number of registered users having administrator authority and the time stamp received together with the instruction. The generated value is used as the initial value of the counter, and the counter processing unit 219 is instructed to set the initial value.
In response to the initial value setting instruction, the counter processing unit 219 sets the initial value of the counter.
When the initial value setting of the counter is completed, the initial value setting unit 220 returns setting completion to the communication processing unit 204.
Upon receiving the setting completion, the communication processing unit 204 transmits a counter initial value setting request to the communication processing unit 304. At the time of transmission, the registration number and time stamp of the user having Administrator authority are also passed along with the request.

Upon receiving a counter initial value setting request from the communication processing unit 204, the communication processing unit 304 instructs the initial value setting unit 320 to set the initial value of the counter in the same manner as the processing on the PLC 200 side. The value setting unit 320 generates a random numerical value based on the number of registered users having administrator authority and the time stamp, and instructs the counter processing unit 319 to set the initial value using the generated value as the initial value of the counter. To do.
The counter processing unit 319 sets an initial value of the counter in response to an instruction for setting an initial value.
As a result, the initial values of the counter processing unit 219 and the counter processing unit 319 become the same value.

Next, the operation of counting up the counter value of the counter processing units 219 and 319 will be described.
The user authentication information change notification unit 216 receives the administrator authority from the engineering environment PC 100 when an additional registration of a user having the administrator authority, a password change of the user having the administrator authority, or deletion of the user authentication information occurs in the engineering environment PC 100. In response to an additional registration request for a user having a password change request for a user having Administrator authority stored in the user authentication information storage unit 205 and a request for deleting user authentication information, the counter processing unit 219 receives one counter value. An instruction to count up is issued, and the same instruction is issued to the counter processing unit 319 on the protected asset device 300 side.
Upon receiving the instruction, the counter processing units 219 and 319 increment the counter value by one.
The value of this counter is cleared when all user authentication information stored in the user authentication information storage unit 205 is deleted (set to 0 (zero)).
The counter value of the counter processing unit 219 is the same as that when the user authentication information in the user authentication information storage unit 205 is updated asynchronously with the update of the regular user authentication information in the engineering environment PC 100, that is, additional registration from the engineering environment PC 100. It is cleared when user authentication information is updated even though no request, password change request, or deletion request has been received (set to 0 (zero)).

In this embodiment, the value of this counter is used as validity confirmation information, and validity confirmation processing is executed.
That is, the communication processing unit 304 receives the count value counted by the PLC 200 from the PLC 200 every time the PLC 200 is activated, and the validity check processing unit 313 receives the count value by the communication processing unit 304. The received count value is compared with the count value counted by the counter processing unit 319 to determine whether the user authentication information currently held by the PLC 200 matches the regular user authentication information.
As long as the user authentication information of the PLC 200 is updated in synchronization with the update of the regular user authentication information in the engineering environment PC 100, the count value of the counter processing unit 219 matches the count value of the counter processing unit 319. On the other hand, when the user authentication information of the PLC 200 is updated without synchronizing with the update in the engineering environment PC 100, the count value of the counter processing unit 219 is cleared, so the count value of the counter processing unit 219 and the counter processing unit The count value of 319 does not match.
For this reason, the validity confirmation processing unit 313 compares the count value every time the PLC 200 is activated. If the count values match, it determines that the user authentication information of the PLC 200 matches the regular user authentication information, while the count value If they do not match, it is determined that the user authentication information of the PLC 200 does not match the regular user authentication information.
The determination result of the validity check processing unit 313 is set in the validity check flag as in the first embodiment.
Similarly to the first embodiment, the validity confirmation flag processing unit 315 performs permission / refusal determination on the access request based on the value of the validity confirmation flag (True / False).

  Thus, a random value is set in the counter as an initial value, and the value of the counter is counted up only when a specific access request is received, so that only the PLC 200 and the protected asset device 300 can know. By performing the validity check according to, unauthorized access to rewriting user authentication information by a malicious user can be prevented.

  In the above, the example in which the counter processing unit 219 and the counter processing unit 319 count up in response to the update request to the user authentication information from the engineering environment PC 100 has been described. The counter processing unit 219 and the counter processing unit 319 may also count up when there is an access request (write / read) to the protected asset stored in the protected asset storage unit 302.

As described above, in the present embodiment,
An apparatus for confirming the validity of user authentication information using information held only by the PLC and the protected asset device in place of the validity confirmation information stored in the validity confirmation information storage unit,
Access request (addition / change / deletion) for user authentication information of a user having Administrator authority stored in the user authentication information storage unit of the PLC, and access request for protected assets stored in the protected asset storage unit of the protected asset device A counter processing unit that counts up a counter value each time (write / read) is received;
An authentication information validity checking device provided with an initial value setting unit for generating and setting the initial value for the counter processing unit based on the number of registered users and the time stamp having Administrator authority stored in the user authentication information storage unit explained.

  100 Engineering Environment PC, 101 Input Unit, 102 Protected Asset Storage Unit, 103 Protected Asset Access Processing Unit, 104 Communication Processing Unit, 105 User Authentication Information Storage Unit, 106 Online User Authentication Processing Unit, 200 PLC, 204 Communication Processing Unit, 205 User authentication information storage unit, 206 Online user authentication processing unit, 207 Initial processing unit, 208 Random number generation processing unit, 209 Session management unit, 210 Validity confirmation information generation unit, 211 Validity confirmation hash generation processing unit, 216 User authentication Information change notification unit, 219 Counter processing unit, 220 Initial value setting unit, 300 Protected asset device, 302 Protected asset storage unit, 303 Protected asset access processing unit, 304 Communication processing unit, 308 Random number generation processing unit, 311 Validity check Hash generation processing unit, 12 Validity Confirmation Information Storage Unit, 313 Validity Confirmation Processing Unit, 314 Validity Confirmation Flag Storage Unit, 315 Validity Confirmation Flag Processing Unit, 317 Protected Asset Deletion Instruction Unit, 318 Validity Confirmation Information Update Processing Unit, 319 Counter Processing Part, 320 initial value setting part.

Claims (11)

An authentication device that holds user authentication information and performs authentication processing for an access request to the protection target information using the held user authentication information, and is a user authentication information of a regular user who has an access right to the protection target information Is connected to the authentication device that is the default user authentication information,
A protection target information storage unit for storing the protection target information;
A verification information storage unit that stores regular user authentication information or information generated from at least part of the regular user authentication information as verification information;
A communication processing unit that receives from the authentication device as verification information held user authentication information held by the authentication device or information generated from at least part of the held user authentication information when the authentication device is activated; ,
When verification information is received by the communication processing unit, verification information and verification target information are collated, and whether or not the retained user authentication information held by the authentication device matches the regular user authentication information An information device having a user authentication information verification unit for determining whether or not. The information device further includes:
When the user authentication information verification unit determines that the retained user authentication information matches the regular user authentication information, the authentication apparatus uses the retained user authentication information for the authentication device, and the user authentication information verification unit The information device according to claim 1, further comprising: an authentication control unit that rejects an access request via the authentication device when it is determined that the retained user authentication information does not match the regular user authentication information. The communication processing unit
Every time the authentication device is activated, the verification information is received from the authentication device,
The user authentication information verification unit
Each time verification information is received by the communication processing unit, verification information and verification target information are collated, and whether or not the held user authentication information held by the authentication device matches the regular user authentication information. The information device according to claim 1, wherein the information device is determined. The information device is
Connected to an authentication device that holds information generated by performing a one-way operation on at least a part of the held user authentication information as confirmation information;
The verification information storage unit
Storing information generated by performing a one-way operation on at least a part of the authorized user authentication information as verification information;
The user authentication information verification unit
Each time the authentication device is activated, a random number is generated and a one-way operation is performed on the verification information using the generated random number,
The communication processing unit
A random number generated by the user authentication information verification unit is transmitted to the authentication device, and information generated by performing a one-way operation on confirmation information using the random number in the authentication device is used as the verification information. Received from the device,
The user authentication information verification unit
Each time the verification information is received by the communication processing unit, the holding user held by the authentication device by comparing the verification information with information generated by performing one-way operation on the verification information 4. The information device according to claim 1, wherein it is determined whether or not the authentication information matches the regular user authentication information. The information device further includes:
Verification information update for updating the verification information stored in the verification information storage unit in response to the update of the regular user authentication information when the regular user authentication information is updated in the management source of the regular user authentication information The information device according to claim 1, further comprising a section. The information device further includes:
When it is necessary to delete the held user authentication information held by the authentication device, the protection target information stored in the protection target information storage unit is deleted, and after the deletion of the protection target information, the verification information 6. The apparatus according to claim 1, further comprising an information deleting unit that deletes the verification information stored in the storage unit and instructs the authentication device to delete the stored user authentication information after the verification information is deleted. Information device described in any one. An authentication device that holds user authentication information and performs authentication processing for an access request to the protection target information using the held user authentication information, and is a user authentication information of a regular user who has an access right to the protection target information The regular user authentication information is the default user authentication information, and every time the regular user authentication information is updated in the regular user authentication information management source, the regular user authentication information in the regular user authentication information management source is updated. It is connected to an authentication device that updates the held user authentication information held in correspondence and counts the number of updates of the regular user authentication information in the management source of the regular user authentication information,
A protection target information storage unit for storing the protection target information;
A counter processing unit that counts the number of updates of the regular user authentication information in the regular user authentication information management source each time the regular user authentication information is updated in the regular user authentication information management source;
A communication processing unit that receives a count value counted by the authentication device from the authentication device when the authentication device is activated;
When the count value is received by the communication processing unit, the received user authentication information that is currently held by the authentication device by comparing the received count value with the count value counted by the counter processing unit An information device comprising: a user authentication information verification unit that determines whether or not the user ID matches the regular user authentication information. The information device is
8. The authentication apparatus according to claim 7, wherein when the stored user authentication information is updated asynchronously with the update of the regular user authentication information at the management source of the regular user authentication information, the count value is cleared. Information equipment described. The information device further includes:
9. The information device according to claim 7, further comprising an initial value setting unit that sets a random value that is the same as the initial value of the count in the authentication device as an initial value of the count by the counter processing unit. The information device further includes:
When the user authentication information verification unit determines that the retained user authentication information matches the regular user authentication information, the authentication apparatus uses the retained user authentication information for the authentication device, and the user authentication information verification unit 10. The authentication control unit according to claim 7, further comprising: an authentication control unit that rejects an access request via the authentication device when the held user authentication information is determined not to match the regular user authentication information. Information equipment described. The information device is
The information device according to claim 1, wherein the information device is an FA (Factor Automation) device connected to a PLC (Programmable Logic Controller).

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