KR101252918B1 - Control device and management device - Google Patents

Abstract

In the present invention, the access request reception processing unit 11 inputs the control program and a random number so that the control program can be operated only on a specific PLC, and the authentication processing unit 10b receives the random number and the unique serial ID of the PLC 200. Hash operation is executed, the authentication ladder automatic generation processing unit 13 selects a dedicated device from the hash value, generates an authentication ladder in which the selected dedicated device is displayed, and the authentication ladder insertion processing unit 14 sends the authentication ladder to the control program. Insert and save. At the time of execution of the control program, the authentication processing unit 10b performs a hash operation on the random number and the serial ID, the dedicated device setting unit 17 selects the dedicated device from the hash value, sets the selected dedicated device to ON, and controls The program execution control unit 16 executes the control program. If the same dedicated device as the authentication ladder is turned on, the control program operates correctly. Otherwise, the control program does not operate.

Description

CONTROL DEVICE AND MANAGEMENT DEVICE}

The present invention relates to a technique for preventing fraudulent use of a program.

More specifically, the present invention relates to a technique for preventing the illegal use of a control program (ladder program) stored in a programmable logic controller (PLC), for example, in a FA (Factory Automation) system.

In general, a FA system uses a password or a method of encrypting a protected asset as a means of preventing unauthorized access to a protected asset such as a control program (ladder program) that is not intended to be disclosed to a third party. .

However, in the method of using a password, even if a password is set for a control program for access control, when a plurality of developers access the control program, a common password is set among the plurality of developers. There are challenges to vulnerabilities such as giving a password that is easy to guess.

In addition, since information used for authentication, such as a control program and a password, is managed separately, and the authentication process is also implemented separately from the control program, access control to the control program cannot be performed unless it is associated with the control program.

For this reason, a method of encrypting the data itself to be protected is taken, but encryption requires special hardware in order to manage the key, resulting in a problem that the device is complicated and expensive.

In addition, in the control program (ladder program) in the FA system, the control signal to the control device is turned on / off in accordance with the on / off state of the device. Therefore, the encryption or decryption process cannot be executed during the execution of the control program. .

Thereby, as a method of preventing alteration or monitoring of a control program without using encryption, there is a method of limiting a response by a preset access authority to an access request to a control program from a monitor device (for example, a patent document). One).

[Prior Art Literature]

[Patent Literature]

Patent Document 1: Japanese Patent Application Laid-Open No. 2005-135165

As described above, in the method of restricting the response to the access request from the monitor apparatus by the access authority set in advance for each control program, the purpose is to perform access control from the monitor apparatus, so that the control program can be executed only on a specific PLC. The control is not performed.

For this reason, if the user has the read authority, the control program can be read from the PLC to the monitor device, and the read control program can be written to another PLC. Therefore, the illegal use of the control program can be made possible by the PLC as the copy destination. There is.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its main object is to prevent unauthorized use of a control program to ensure that a control program (ladder program) that is permitted to be used only for a specific control device can operate only on a specific control device. It is to realize the function.

The control apparatus which concerns on this invention contains the unique identification information storage part which stores the unique identification information uniquely set to the said control apparatus, and the device number of the target device made into the control process of the said control apparatus, A program input unit for inputting a ladder program which is not permitted to be used by a device other than the control device as a main program, and a ladder program that prevents the use of the main program by devices other than the control device based on the unique identification information. An authentication program generation unit for generating an authentication program as an authentication program, a program synthesis unit for synthesizing the main program and the authentication program into a synthesis program, and a program storage unit for storing the synthesis program, wherein the authentication program generation unit is a device of a target device. The doctor's number Manages the device numbers of a plurality of authentication devices used for authentication as the device number as the authentication device number, selects one or more authentication device numbers based on the unique identification information, and selects the selected authentication device As a ladder program including a number, when executed together with the main program as the synthesis program, the device for authentication for selection is correctly selected based on the unique identification information independently of the selection operation of the authentication program generator, and the selection is performed. When a predetermined setting process is performed for each of the selected authentication devices corresponding to the device number for authentication, the line is operated normally and the main program operates normally, and when the line is executed together with the main program as the synthesized program, the line For each of the authentication devices for when the setting process is not performed, and a ladder program for the operation of the main program without having to stop the normal operation characterized by generating a certification program.

In the present invention, when storing the main program, a ladder program including the selected authentication device number selected based on the unique identification information uniquely set in the control device is generated as an authentication program, and the authentication program is synthesized in the main program. If the selection authentication device number is correctly selected based on the unique identification information at the time of execution of the main program, and the setting processing is performed on the selection authentication device, the main program operates normally. If the setting processing is not performed, authentication is performed. The main program is stopped by the program.

For this reason, the main program can be used normally in the control device, while the main program cannot be used in the device where the use of the main program is not permitted, and thus the illegal use of the main program can be prevented.

1 is a diagram showing a system configuration example according to Embodiment 1;
2 is a flowchart showing an example of operation according to the first embodiment;
3 is a flowchart showing an operation example according to the first embodiment;
4 is a diagram illustrating an example of an authentication ladder according to the first embodiment;
5 is a diagram showing a setting example of a dedicated device according to the first embodiment;
6 is a diagram showing an example of the system configuration according to the second embodiment;
7 is a diagram showing an example of the system configuration according to the third embodiment;
8 is a diagram showing an example of the system configuration according to the fourth embodiment;
9 is a diagram showing an example of the system configuration according to the fifth embodiment;

In Embodiments 1 to 5, a technique for preventing a counterfeit product of a PLC from being manufactured by illegal copying of a control program (ladder program) stored in a PLC in an FA system will be described.

More specifically, when writing the control program to the PLC, authentication information is generated using a serial ID for identifying the PLC object and a random number generated in the engineering environment, and the PLC is associated with the control program. An authentication ladder that can be inserted into the control program is automatically generated from the generated authentication information and inserted into the control program.

When the control program is executed, it is confirmed that the execution is performed on the PLC which has been associated with the inserted authentication ladder, thereby illegally copying the control program to another PLC to prevent fraudulent use of a counterfeit product or the like.

Here, the authentication ladder is a ladder program inserted into a control program which is a main program, and is an example of an authentication program.

More specifically, the ladder program inserted in the control program to confirm that the dedicated device corresponding to the specific device number is turned on when the control program is executed is the authentication ladder.

In Embodiments 1 to 5, authentication information (hash value) is generated as a hash function (one-way function) by inputting a serial ID of the PLC and a random number generated by the engineering environment side, and based on this authentication information The device number for checking on / off of the dedicated device is determined. The ladder program which contains the device number determined based on this authentication information is an authentication ladder.

Since the authentication information generated here is generated as a hash function with the serial ID of the PLC as input, the authentication information generated for each PLC is different.

The control program is a ladder program that includes a device number of a target device to be subjected to control processing of a PLC such as an input device or an output device, and is not permitted to be used by devices other than the designated PLC.

The control program is an example of the main program.

The program after the authentication ladder is inserted into the control program is also called a synthesized program.

The dedicated device is a memory for storing data and on / off signals used in a control program provided in the PLC, and can be set only by the firmware of the PLC, and cannot be set by the user even when using an engineering environment. .

The dedicated device, unlike the target device, is a device that is specially provided in order to prevent unauthorized use of the control program. In the dedicated device, a device number pseudo-device number of the target device is set. The dedicated device is an example of the device for authentication, and the device number of the dedicated device is an example of the device number for authentication.

When a user creates a control program of a PLC using an engineering environment, a project for managing the control program, parameters, authentication information, and the like is created for each PLC.

Based on the above, each of Embodiment 1-5 is demonstrated below.

(Embodiment 1)

1 shows an example of the system configuration of an illegal use prevention system according to the present embodiment.

The illegal use prevention system shown in FIG. 1 is an illegal use prevention system of an FA device control program for allowing a control program stored in a PLC to be executed only on a specific PLC.

The illegal use prevention system which concerns on this embodiment is divided roughly into the engineering environment side personal computer (PC) 100 and the programmable logic controller (PLC) 200. FIG.

The engineering environment side PC 100 is a computer including a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), a magnetic disk device, a communication board, and the like.

In this case, programs for realizing the functions (“parts”) indicated as internal elements of the engineering environment side PC 100 are stored in, for example, a magnetic disk device, and the CPU executes each function by appropriately reading these programs.

The PLC 200 stores a control program which is a ladder program, and the CPU executes the control program to control the device.

The engineering environment side PC 100 is an example of a management apparatus, and the PLC 200 is an example of a control apparatus.

In addition, the internal structure of the engineering environment side PC 100 and PLC200 is mentioned later.

2 is a flowchart showing an operation example according to the present embodiment.

Fig. 2 specifically shows a process flow when security setting is made when writing a control program to the PLC and the control program is associated with the PLC.

Details of the processing flow of FIG. 2 will be described later.

3 shows a process flow when generating an authentication ladder in the PLC, inserting the generated authentication ladder into the control program, and storing the control program in the PLC.

Details of the processing flow of FIG. 3 will be described later.

4 is an example of an authentication ladder generated automatically based on authentication information generated from a random number for authentication ladder generation and a serial ID of a PLC.

Details of FIG. 4 will be described later.

5 is an example when a dedicated device is set based on the authentication information in the initialization process of the firmware when the PLC is powered on.

Details of FIG. 5 will be described later.

Next, with reference to FIG. 1, the element which comprises the system for preventing the illegal use of the FA device control program which confirms that it is execution on the PLC authorized at the time of execution of the control program stored in the PLC is described.

First, the component of the engineering environment side PC 100 is demonstrated.

1 is an input unit for the user in the engineering environment side PC 100 to create a PLC control program or set parameters by using a keyboard or a mouse.

2 is a control program creation unit in which a user creates a control program of a PLC.

3 is a control program storage unit for storing the control program created by the control program creating unit 2.

4 is an access request transmission processing unit that transmits an access request to the PLC, such as writing to the PLC or reading from the PLC, of the control program stored in the control program storage unit 3 to the PLC.

5 is a control program which receives a write instruction of a control program from a user by the input unit 1 and requests a read access request transmission processing unit 4 to write to the PLC from the control program stored in the control program storage unit 3. It is a write request unit.

6a is a security setting unit for validating security settings from invalid for the control program created by the engineering environment side PC 100.

7 is a random number generation processing unit that generates a random number.

More specifically, the random number generation processing unit 7 uses a project (information composed of control programs or parameter settings created in units of FA devices) when the security setting of the security setting unit 6 is set from invalid to valid. It is unique and generates a random number used as an input when generating an authentication ladder and a random number (challenge value) for challenge response (challenge & response) authentication when authenticating between the engineering environment and the PLC.

8a is an authentication ladder generation random number memory for storing a random number generated by the random number generation processing unit 7 in order to associate the control program with the PLC to which the control program is written and to generate the authentication ladder when the security setting is enabled. It is wealth.

9a is a serial ID storage unit that stores a serial ID (for example, a manufacturing number, etc.) for individual identification of a PLC read from a PLC which is a control destination of a control program when security setting is enabled.

10a is an authentication processing unit which performs authentication by comparing the authentication information generated by the PC 100 on the engineering environment side with the authentication information generated by the PLC 200.

More specifically, the authentication processing unit 10a writes / reads the control program to the PLC when the random number generation request to the random number generation processing unit 7 and the security setting of the security setting unit 6a are valid. The random number generated by the random number generation processing unit 7 and the random number stored in the random number storage unit 8a for authentication ladder generation 8a and serial ID storage unit 9a at each time in order to confirm that the PLC as the access destination is the associated PLC. ), The hash value generated by the hash function is used as the authentication information, and the authentication information is compared with the authentication information generated by the PLC.

Next, the components of the PLC 200 will be described.

9b is a serial ID storage unit that stores a serial ID (e.g., a serial number) for identifying a PLC which the PLC maker sets at the time of product release and for which the user cannot rewrite the PLC.

The serial ID is uniquely set in the PLC 200 and is an example of unique identification information.

The serial ID storage unit 9b is an example of a unique identification information storage unit.

6b is a security setting unit for validating security settings for restricting access to the control program.

The security setting unit 6b restricts access to a control program that receives a request for validating security settings on the engineering environment side and stores them in the PLC in synchronization with validating the security settings on the engineering environment side.

8b is an authentication ladder generation random number storage unit for storing random numbers transmitted with the request for validating the security setting.

The random number stored in the authentication ladder generation random number storage unit 8b is generated by the random number generation processing unit 7 of the engineering environment side PC 100 and is the same random number as the random number stored in the authentication ladder generation random number storage unit 8a. to be.

The authentication ladder generation random number storage section 8b is an example of a random number storage section.

11 is an access request reception processing section that accepts an access request sent from the access request transmission processing section 4 of the engineering environment on the PLC side and executes processing according to the request contents.

In addition, the access request reception processing unit 11 inputs a control program (ladder program) together with a control program write request from the engineering environment side PC 100.

As described above, the control program is a ladder program that includes the device number of the target device to be subjected to the control processing of the PLC 200, and is not permitted to be used by devices other than the designated PLC. The control program is an example of the main program.

The access request reception processing section 11 is an example of a program input section.

10b is an authentication processing unit that performs a hash operation (one-way operation).

The authentication processing unit 10b is a random number stored in the authentication ladder generation random number storage unit 8b, a serial ID stored in the serial ID storage unit 9b, and a random number sent together when a generation request for authentication information is generated. A hash value (response) is generated using a hash function with (challenge value) as input.

More specifically, when the security setting of the security setting unit 6b is effective, the authentication processing unit 10b receives an authentication request from the engineering environment before generating the authentication ladder (authentication program). A hash value (response value) is generated in accordance with a request for generating authentication information from the access request reception processing unit 11.

The authentication processing unit 10b is an example of a one-way computing unit.

12, upon receiving the write request of the control program from the access request reception processing unit 11, checks the security setting of the security setting unit 6b, and proceeds to the process of inserting an authentication ladder when the security setting is valid. If it is invalid, the control program write processing unit instructs the control program to proceed to write processing in the PLC in a state without including the authentication ladder.

13 is an authentication ladder automatic generation processing unit that generates an authentication ladder (authentication program).

The authentication ladder is a ladder program which can be directly inserted into the control program, and is a ladder program for preventing the use of the control program by devices other than the PLC 200.

When the authentication ladder automatic generation processing unit 13 stores the control program in the execution control program storage unit 15, the authentication ladder automatic generation processing unit 13 generates a specific device in the dedicated device (authentication device) based on the hash value generated by the authentication processing unit 10b. The number is selected, and an authentication ladder including the number of the selected specific device (device number for selective authentication) is generated.

In the authentication ladder insertion processing unit 14, the authentication ladder is combined with the control program and stored in the control program storage unit 15 for execution.

Although details will be described later, before the control program execution control unit 16 executes the control program and the authentication ladder, the authentication processing unit 10b independently of the generation of the authentication ladder by the authentication ladder automatic generation processing unit 13 is performed. A hash value is generated based on the serial ID and the random number, the dedicated device setting unit 17 selects a device number of a specific dedicated device based on the hash value, and predetermined setting processing for the dedicated device corresponding to the selected device number. (Setting processing for bringing the dedicated device into an on state from the off state) is executed.

If the device number identical to the device number of the dedicated device included in the authentication ladder is correctly selected by the dedicated device setting unit 17, and the setting processing is performed for the dedicated device corresponding to the device number, the control program is executed. When the control unit 16 executes the control program and the authentication ladder, the authentication ladder operates normally. As a result, the control program operates normally. On the other hand, if the correct device number is not selected and, as a result, the setting processing is not performed for the correct dedicated device, the authentication ladder operates normally when the control program execution control unit 16 executes the control program and the authentication ladder. As a result, the operation of the control program is stopped.

The authentication ladder automatic generation processing unit 13 is an example of an authentication program generation unit.

In addition, the authentication ladder automatic generation processing unit 13 includes either an authentication ladder (leading authentication program) in which all of the selected device numbers are included and placed at the head of the control program, and the selected device number includes a plurality of control programs. At least one of the two or more authentication ladders (insertion authentication program) to be inserted at the insertion position of is generated.

For example, Fig. 4A is an example of the authentication ladder placed at the head of the control program, and Fig. 4B is an example of the authentication ladder inserted at the insertion position in the middle of the control program.

14 is an authentication ladder insertion processing unit for synthesizing the authentication ladder generated automatically by the authentication ladder automatic generation processing unit 13 with the control program.

In the case of an authentication ladder arranged at the beginning of the control program (in the case of the authentication ladder illustrated in Fig. 4A), the authentication ladder insertion processing unit 14 is placed at the beginning of the control program, and the insertion position in the middle of the control program is placed. In the case of the authentication ladder to be inserted into (in the case of the authentication ladder illustrated in Fig. 4 (b)), it is inserted at the designated insertion position.

The authentication ladder insertion processing unit 14 is an example of a program synthesis unit.

The program after the control program and the authentication ladder are synthesized is also called a synthesized program.

15 is an execution control program storage unit for storing a control program (synthesis program) after the authentication ladder is synthesized by the control program or the authentication ladder insertion processing unit 14 created on the engineering environment side.

The execution control program storage unit 15 is an example of a program storage unit.

16 is a control program execution control unit that executes the control program stored in the control program storage unit 15 for execution when the PLC 200 enters the execution mode.

The control program execution control unit 16 is an example of a program execution unit.

17 is a dedicated device from a random number stored in the authentication ladder generation random number storage unit 8b and a hash value generated from the serial ID stored in the serial ID storage unit 9b by the initialization processing of the firmware in the PLC when the PLC is powered on. Is a dedicated device setting unit that extracts a device number and sets a dedicated device corresponding to the extracted device number to on.

The dedicated device setting unit 17 is an example of a setting processing unit.

Next, the operation at the time of writing a control program (ladder program) on an engineering environment to a PLC is demonstrated using FIG. 1, FIG. 2, FIG.

First, the procedure for creating a control program on the engineering environment side PC 100 will be described.

A user creates a control program using the input unit 1 and the control program creating unit 2 of the engineering environment side PC 100, and stores the created control program in the control program storage unit 3.

Next, the procedure at the time of initial registration at the time of writing the control program created on the engineering environment side PC 100 to the PLC 200 is demonstrated.

The user connects the engineering environment side PC 100 and the PLC 200 by a USB (Universal Serial Bus) cable or the like.

Next, data transmission and reception are performed between the engineering environment and the PLC by using the access request transmission processing section 4 and the access request reception processing section 11.

When the user instructs the writing of the control program stored in the control program storage unit 3 to the PLC by using the input unit 1 (S201 in Fig. 2), the control program writing request unit 5 receives the control program storage unit ( The control program is read from 3) (S202).

The control program write request unit 5 confirms with the security setting unit 6a whether the security settings are valid or invalid (S203).

If the security setting is invalid, the control program write request unit 5 inquires of the user whether or not to enable the security setting.

When the instruction to leave it invalid from the user is received, the control program write request unit 5 instructs the access request transmission processing unit 4 to write the control program (S209).

When the user is instructed to enable the security setting, the control program writing request unit 5 effectively sets the security setting unit 6a (S204), and the authentication processing unit 10a performs control of the control program and the PLC. Requires the generation of an authentication ladder generation random number used for association.

The authentication processing unit 10a which has received the request for random number generation requests the random number generation processing unit 7 for random number generation.

The random number generation processing unit 7 generates a random number (S205) and transfers the random number to the authentication processing unit 10a.

The authentication processing unit 10a returns the received random number to the control program write request unit 5.

The control program write request unit 5 stores the random number received from the authentication processing unit 10a in the authentication ladder generation random number storage unit 8a (S206), and also generates the authentication ladder for the access request transmission processing unit 4. A random number is issued to issue a request to validate the security settings of the PLC.

When the access request transmission processing section 4 receives a request for validating the security setting of the PLC, the access request reception processing section 11 of the PLC 200 requests the validity of the security setting and also transmits a random number for authentication ladder generation. By doing so, the control program is associated with the PLC (S207). At this time, the control program does not transmit to the PLC 200.

In the PLC 200, when the access request reception processing unit 11 receives a request for validating the security setting, the access request reception processing unit 11 effectively sets the security setting unit 6b (S210), and the authentication environment unit PC ( It is required to save the random number for authentication ladder generation generated in 100) and to acquire the serial ID of the PLC.

The authentication processing unit 10b stores the authentication ladder generation random number in the authentication ladder generation random number storage unit 8b (S211), and serially identifies the PLC 200 stored in the serial ID storage unit 9b. The ID is read and returned to the access request reception processing unit 11.

This serial ID is information that the manufacturer of the PLC arbitrarily sets when shipping the PLC, and is information that cannot be set / changed by the user.

When the access request reception processing unit 11 receives the serial ID from the authentication processing unit 10b, the access request reception processing unit 11 adds the serial ID received in response to the request for validating the security setting and returns it to the access request transmission processing unit 4 (S212).

In the engineering environment side PC 100, when the access request transmission processing section 4 receives a response from the access request reception processing section 11, the access request transmission processing section 11 stores the serial ID of the PLC 200 added to the control program write request section ( Returning to 5), the control program write request unit 5 stores it in the serial ID storage unit 9a (S208).

In this embodiment, the control program and PLC are controlled by the authentication ladder generation random number stored in the authentication ladder generation random number storage units 8a and 8b and the serial ID of the PLC stored in the serial ID storage units 9a and 9b. The information generated using the hash function from these two pieces of information is regarded as authentication information.

The control program write request section 5 requests the access request transmission processing section 4 to write the control program, and the access request transmission processing section 4 sends the write request and the control program to the access request reception processing section 11 of the PLC. It transmits (S209) (S301 of FIG. 3).

In the PLC 200, the access request receiving processing unit 11 instructs the control program writing processing unit 12 to write the control program when receiving the write request of the control program.

When the control program write processing unit 12 receives a write instruction from the control program, the control program write processing unit 12 confirms the security setting of the security setting unit 6b (S302). The data is stored in the unit 15 (S309).

When the security setting has been made effective, the control program write processing unit 12 instructs the authentication ladder automatic generation processing unit 13 to generate the authentication ladder.

The authentication ladder automatic generation processing unit 13 receives a generation instruction of the authentication ladder from the control program write processing unit 12 and instructs the authentication processing unit 10b to generate authentication information.

The authentication processing unit 10b reads the random number stored in the authentication ladder generation random number storage unit 8b and the serial ID stored in the serial ID storage unit 9b (S304, S305), and compares the random number and the serial ID. Authentication information (hash value) is generated using a hash function (one-way function) (S306), and the generated authentication information (hash value) is returned to the authentication ladder automatic generation processing unit 13.

The authentication ladder automatic generation processing unit 13 automatically generates an authentication ladder (ladder program for authentication purposes) based on the authentication information received from the authentication processing unit 10b (S307), and automatically generates the authentication ladder insertion processing unit 14. Instructs insertion of the generated authentication ladder into the control program.

The authentication ladder insertion processing unit 14 inserts the authentication ladder generated by the authentication ladder automatic generation processing unit 13 at a specific position of the control program created by the user using the engineering environment side PC 100 (S308).

The authentication ladder insertion processing unit 14 stores the control program (synthesis program) in which the authentication ladder is inserted in the execution control program storage unit 15 (S309), and the process of writing the control program is completed.

In the present embodiment, two random numbers generated by the engineering environment side PC 100 and two serial IDs of the PLC 200 are input to the generation of authentication information. The authentication information may be generated in combination with the CPU type of the CPU (Central Processing Unit) mounted on the CPU.

This CPU type is information handled in an engineering environment determined when the PLC 200 as a control program writing destination is selected on the engineering environment, and is also internally held in advance in the PLC 200 side, and therefore is a communication path (engineering environment). Since the information does not flow between the module and the PLC), the authentication information becomes difficult to guess.

Next, with reference to FIGS. 4 and 5, a description will be given of a method for setting a dedicated device in the generation and insertion of an authentication ladder based on the authentication information, and an initialization process performed when the PLC is powered on.

Here, a method of generating an authentication ladder when the serial ID of the PLC 200 is set to "009910987654321" and the random number for generating the authentication ladder to "1234567890", for example, will be described.

Further, the authentication information generated by the hash function by inputting the authentication ladder generation random number and the serial ID in the authentication processing unit 10b is, for example, "EA082DFE1CBA7816".

Since the authentication information generated by the hash function is generated using the serial ID of the PLC 200, since the serial ID is different in other PLCs, the same authentication information is not generated.

The authentication ladder automatic generation processing unit 13 divides the generated authentication information into 1 byte, and selects the partitioned value as the device number of the dedicated device.

For example, if "EA" of the first 1 byte is selected as the device number (decimal display) of the dedicated device, this is A234. Here, "A" means a dedicated device.

Similarly, if the 2nd byte and the 3rd byte are selected as the device number of the dedicated device, they are A8, A45, A254, A28 (hereinafter omitted).

The device number selected in this manner corresponds to the device number for selective authentication.

In addition, "X" is used for the device number of the target device of the PLC 200, and the device number of the target device is displayed in the control program like "X50", but approximating this to the device number of the dedicated device in the authentication ladder. `` A234 ''. In this manner, in the authentication ladder, a device number that is a pseudo device number of a target device is used.

The authentication ladder automatic generation processing unit 13 generates an authentication ladder (ladder program) as shown in FIG. 4 based on these information.

4A is an example of an authentication ladder in which all selected device numbers (A234, A8, A45, A254, etc.) are included and placed at the head of the control program.

The authentication ladder shown in FIG. 4 (a) checks the on / off state of the dedicated device (dedicated device corresponding to A234, A8, etc.) at the time of execution, and executes the control program when there is any dedicated device in the off state. The device (E99 in the example of Fig. 4A) is set to ON to stop the operation.

Since the PLC can define the execution type such as only one execution or execution every fixed cycle for the control program, the authentication ladder is set to be executed only once when the control program is executed.

In addition, the authentication ladder automatic generation processing unit 13 selects the device number of the dedicated device of the authentication ladder generated above as the number of steps of the control program, and inserts the authentication ladder into the position of the step number of the control program.

As shown in Fig. 4B, for example, in the case of the dedicated device A234 in the above example, the device number 234 is selected as the number of steps, and the authentication ladder is inserted in the 234th step of the control program.

When inserting, however, the device numbers are sorted, and then the authentication ladder is inserted in the corresponding step number in the order of the smallest number.

This makes it possible to confirm that the control program is running on the associated PLC even during the execution of the control program.

For example, when A234 of the dedicated device is turned off when the authentication ladder is written to another PLC and executed, the command of the output unit of the inserted authentication ladder is not executed in the example shown in FIG. Y0 described is not set to ON).

For this reason, since the control program cannot operate normally and the FA device connected to the PLC cannot control normally, it is possible to prevent the illegal use of the control program.

In the example of FIG. 4, the authentication ladder generated by the automatic authentication ladder generation processing unit 13 is represented in the form of a ladder program for easy explanation, but the actual authentication ladder generated on the PLC 200 is generated in the execution code format. .

Next, the operation when setting the dedicated device in the initialization process of the firmware when the PLC 200 is powered on will be described.

By the initialization process of the firmware, the dedicated device setting unit 17 clears the dedicated device to 0 and checks whether the security setting unit 6b of the PLC 200 is valid.

If the security setting is invalid, the setting for the dedicated device does nothing.

When the security setting is valid, the dedicated device setting unit 17 requests generation of authentication information from the authentication processing unit 10b, and the authentication processing unit 10b having received the request generates the authentication ladder generation random number storage unit 8b. Authentication information (hash value) is generated using a hash function from the random number stored in the controller and the serial ID of the PLC stored in the serial ID storage unit 9b.

The dedicated device setting unit 17 receives the authentication information (hash value) generated by the authentication processing unit 10b, and stores the authentication information as one byte as the authentication ladder automatic generation processing unit 13 generates the device number of the dedicated device. Is divided into a device number, and the dedicated device corresponding to the device number is set to ON.

In the example shown in FIG. 5, it is a case where the dedicated devices of A234, A8, A45, A254, and A28 are set to ON.

When the initialization processing in the firmware ends and the PLC 200 enters the execution mode (execution of the control program), the control program execution control unit 16 stores the control program stored in the execution control program storage unit 15. Is executed, and the authentication ladder (FIG. 4 (a)) placed at the head of the control program confirms the on / off state of the specific device of the dedicated device set in the initialization process, and any one of them is to be confirmed. When the dedicated device is turned off, it is determined that the control program is an operation on a PLC that is illegally copied, and the execution of the control program can be stopped.

Also, even when the control program is executed, when the illegal use of the control program is confirmed by the authentication ladder inserted in the control program (Fig. 4 (b)), and the illegal use is confirmed, the control program does not operate normally. The use on the counterfeit goods by illegal copying can be prevented.

In addition, since the PLC automatically generates the authentication ladder and the authentication ladder is executed at the time of execution of the control program, the illegal use is judged. Therefore, the illegal use of the control program can be prevented without the user being aware of it.

When the PLC 200, which is permitted to use the control program, uses the control program, the same serial ID and random number as the serial ID and random number used when generating the authentication ladder are used. Therefore, the correct device number is used in the initialization process. (The same device number as the device number included in the authentication ladder) is selected, and the dedicated device will be set correctly.

For this reason, the PLC 200 which is permitted to use the control program can always operate the control program normally.

On the other hand, devices (other than PLC 200) that are not permitted to use the control program do not know the serial ID and random number used by PLC 200 at the time of authentication ladder generation. The device number is not selected and therefore the dedicated device is not set correctly.

For this reason, in the apparatus which is not permitted to use the control program, the operation of the control program is stopped and the control program cannot be used.

As described above, according to the present embodiment, authentication information is generated from the random number generated by the engineering environment side when the serial ID and the control program of the PLC are created for the control program stored in the PLC, and the control program is generated from the generated authentication information. By automatically generating an authentication ladder that can be directly inserted into the program, and confirming that the program is executed on a PLC previously associated with the execution of the control program, authentication is performed between the control program and the PLC without the user's awareness, and the control is performed according to the authentication result. By stopping the execution of the program, the illegal use of the control program can be prevented.

As described above, in the present embodiment, even if a control program (ladder program) controlling a FA (Factory Automation) device is copied illegally to another FA device, the FA device control for preventing the control program from operating normally on the FA device of the copy destination. In the system for preventing the illegal use of a program, an output device is output in accordance with an on / off command signal of an input device based on an engineering environment (application) and a control program for setting or confirming a control program or a parameter for a FA device. Is a device for preventing the illegal use of a control program realized by a programmable logic controller (PLC) that performs sequence control (operating an object as desired according to a predetermined order and condition) by turning on / off. The user can create a control program or parameter An input unit for instructing input and execution of a function, a control program generator for creating a control program (ladder program) executed by the user on the PLC using the input unit, and a PLC for the PLC created by the control program generator. A control program storage unit for storing the control program, an access request transmission processing unit for requesting the PLC to write / read the control program or parameters and receive the response from the engineering environment, and the control program storage unit A control program write request unit that executes a process for writing a control program to the PLC, a security setting unit to be set only when the security function for the control program created on the engineering environment is enabled, and when generating an authentication ladder in the PLC. PLC with random number or control program used A random number generation processing unit for generating a random number used for authentication at this time and a random number generation request from the control program write request unit are requested to generate a random number to the random number generation processing unit, or authentication is performed between the control program and the PLC. The authentication processing unit generates authentication information using a hash function (one-way function) from a random number or information for identifying an individual object for use in generating the authentication ladder by the PLC generated by the random number generation processing unit. An authentication ladder generation random number storage unit for storing random numbers and a serial ID (manufacture number, etc.) for object identification of a PLC extracted from the PLC when the control program stored in the control program storage unit is first written to the PLC. Serial ID storage to store and access request from engineering environment An access request reception processing unit for receiving the request and transmitting the request contents to each processing unit according to the access request, a security setting unit for setting only when the security function for the control program stored in the PLC is enabled, and an authentication ladder. The authentication ladder generation random number storage unit for storing the random number generated and transmitted by the engineering environment side, the serial ID storage unit for storing the serial ID for identifying the PLC object, and the control from the access request reception processing unit A control program write processing unit that writes a control program in response to a write request of a program; and a random number stored in the authentication ladder generation random number storage unit and the serial ID memory when a security function of the security setting unit is set to be valid; From the serial ID stored in the An authentication ladder is automatically generated based on a hash value generation processing unit that generates authentication information using the same algorithm as the authentication processing unit on the near environment side, and a hash value generated by the hash value generation processing unit when writing a control program to a PLC. The authentication ladder automatic generation processing unit, the authentication ladder insertion processing unit for inserting the authentication ladder generation generated by the authentication ladder automatic generation processing unit into a control program transmitted from an engineering environment, and the security function of the security setting unit are set to invalid. Is a control program storage unit for storing the control program transmitted from the engineering environment as it is or storing the control program in which the authentication ladder is inserted in the authentication ladder insertion processing unit when the security function is set to be effective; In mode From the control program execution control unit that executes the control program stored in the execution control program storage unit, and from the random number for authentication ladder generation and serial ID by the initialization processing executed by the firmware mounted in the PLC when the PLC is powered on. The illegal use prevention system of the FA apparatus control program which provided the dedicated device setting part which sets the dedicated device in PLC based on the hash value produced | generated by the said authentication processing part was demonstrated.

(Embodiment 2)

In the present embodiment, a function of adjusting the number of authentication ladders automatically generated by the authentication ladder automatic generation processing unit 13 will be described in consideration of the influence of the scale and performance aspects of the control program created in the engineering environment.

Fig. 6 is a functional configuration of a system for preventing illegal use of an FA device control program which adjusts the number of authentication ladders to be automatically inserted in consideration of the influence on the scale and performance of the control program.

Since the internal structure of the engineering environment side PC 100 is the same as that of FIG. 1, description is abbreviate | omitted.

In the PLC 200, an execution constraint time storage 18, an authentication ladder performance confirmation unit 19, and an authentication ladder insertion determination unit 20 are added in this embodiment.

Elements other than these are the same as what was shown in FIG.

The execution time limit storage unit 18 stores the time limit for executing the control program set by the user.

That is, the execution restriction time storage unit 18 stores the allowable range of the execution time of the program (synthesis program) after the control program and the authentication ladder have been combined as the restriction time (allowing time).

The execution constraint time storage 18 is an example of the allowable time storage.

The authentication ladder performance verification unit 19 calculates the difference between the constraint time stored in the execution constraint time storage unit 18 and the execution time of the control program, and checks the empty time in which the authentication ladder can be inserted.

That is, the authentication ladder performance verification unit 19 predicts the execution time of the control program and calculates the difference between the execution time (prediction time required) and the constraint time of the predicted control program as the free time.

The authentication ladder performance confirmation unit 19 is an example of the time required prediction unit.

The authentication ladder insertion determination unit 20 depends on the size of the control program (e.g., the number of steps) requested for writing from the engineering environment side PC 100 to the PLC 200, or the free time calculated by the authentication ladder performance confirmation unit 19. Determine the number of authentication ladders to insert.

That is, the authentication ladder insertion determining unit 20 determines the device number of the device number to be included in the authentication ladder based on the free time calculated by the authentication ladder performance checking unit 19 (difference between the execution time of the control program and the restriction time). Determine the number.

In this case, the automatic authentication ladder generation processing unit 13 selects the number of authentication device numbers determined by the authentication ladder insertion determination unit 20 to generate the authentication ladder.

The authentication ladder insertion determining unit 20 determines whether the program size of the control program is greater than or equal to the predetermined size, and if the program size of the control program is less than the predetermined size, the authentication ladder automatic generation processing unit 13 determines the authentication ladder. If generation is suspended and the program size of the control program is equal to or larger than the predetermined size, the automatic authentication ladder generation processing unit 13 instructs generation of the authentication ladder.

The authentication ladder insertion determination unit 20 is an example of the number determination unit and the program size determination unit.

Next, in the process of writing the control program to the PLC 200, the operation when determining the number of authentication ladders to be inserted in consideration of the influence on the scale and performance aspects of the control program will be described.

The constraint time stored in the execution constraint time storage unit 18 is set by the user in the engineering environment side PC 100 and executed by a parameter write request from the engineering environment side PC 100 in the same manner as the control program writing. It is stored in the constraint time storage unit 18.

This restriction time is a time during which the execution of the control program should be completed within the time specified by the user, for example, a time during which the execution of the control program should be completed within the period specified in the case where the execution type of the control program is set as the periodic cycle.

When the control program write processing unit 12 receives the write request of the control program, the control program write processing unit 12 notifies the authentication ladder performance confirmation unit 19 of the write request of the control program.

The authentication ladder performance verification unit 19 extracts the restriction time stored in the execution restriction time storage unit 18, calculates an expected execution time from the number of instructions in the control program, and then executes the execution restriction time storage unit 18 from the execution restriction time storage unit 18. Check the difference with the extracted constraint time.

Since the execution time (reference) is determined for various commands of the control program, the authentication ladder performance confirmation unit 19 can calculate the expected execution time.

The authentication ladder performance confirmation unit 19 confirms the free time that the authentication ladder can insert according to the difference between the constraint time and the expected execution time, and transfers the free time to the authentication ladder insertion determiner 20.

The authentication ladder insertion determination unit 20 checks the size of the control program that has received the write request, and if the scale is small, stops the insertion of the authentication ladder (the authentication ladder automatic generation processing unit 13 generates the authentication ladder. The control program in the state before the authentication ladder is inserted is stored in the control program storage unit 15 for execution.

For example, a malicious user may make a request for writing a dummy control program, and the engineering environment may read the control program in which the authentication ladder is inserted, thereby easily interpreting the method of generating the authentication ladder inserted in the control program. This is to prevent it.

As a criterion for stopping the insertion of the authentication ladder, for example, when generating the authentication ladder, the authentication information is divided into 1 byte. Therefore, when the number of steps of the control program is 256 steps or less, the insertion of the authentication ladder into the control program is stopped. I think.

In the case of a control program of sufficient size, the authentication ladder insertion determination unit 20 determines the number of authentication ladders that can be inserted based on the free time calculated by the authentication ladder performance confirmation unit 19.

In addition, when the control program is large, the insertion position of the control program is concentrated in the first half (up to 255 steps), so that the authentication ladder insertion determination unit 20 allows the authentication ladder to be inserted into the entire control program. In order to do this, a method of calculating the number of steps is determined according to the scale of the control program.

For example, in Embodiment 1, the value which divided authentication information into 1 byte was regarded as the number of steps, but the method which considers the value which divided authentication information into 2 bytes and 3 bytes according to the scale of a control program is considered as the number of steps.

As described above, when the authentication ladder insertion determination unit 20 inserts the authentication ladder illustrated in FIG. 4B into the control program, the authentication ladder insertion determination unit 20 uses the predetermined insertion positioning algorithm (for example, the authentication information shown in the first embodiment). When the insertion position determined according to the byte division algorithm is focused on a specific part of the control program, an algorithm other than the insertion positioning algorithm, in which the insertion position of the authentication ladder is more distributed in the control program (for example, , The insertion position is determined according to the algorithm for dividing the authentication information into 2-byte units and 3-byte units).

The authentication ladder insertion determining unit 20 also notifies the authentication ladder automatic generation processing unit 13 of the calculation algorithm of the number of authentication ladders that can be inserted into the control program and the number of steps for inserting the authentication ladder.

The authentication ladder automatic generation processing unit 13 generates an authentication ladder of the number of devices indicated by the authentication ladder insertion determination unit 20 in accordance with the algorithm instructed by the authentication ladder insertion determination unit 20.

In addition, the generation procedure itself of the authentication ladder by the authentication ladder automatic generation processing unit 13 is the same as that in the first embodiment.

As described above, according to the present embodiment, by adjusting the number of insertion of the authentication ladder in consideration of the influence on the performance aspect at the time of execution of the control program, the illegal use of the control program can be prevented without disturbing the actual operation of the control program. have.

In addition, by changing the position at which the authentication ladder is inserted in accordance with the scale of the control program, it is difficult to analyze by a malicious user, thereby making it possible to detect fraudulent use in a wide range of the running control program.

As described above, in the present embodiment, an execution restriction time storage unit for storing the restriction time of the execution time of the control program set by the user in order to consider the effect on the performance side when generating the authentication ladder in the authentication ladder automatic generation processing unit; An authentication ladder performance verification unit which calculates a difference between the constraint time stored in the execution constraint time storage unit and the execution time of the control program created by the user and checks the empty time for inserting the authentication ladder; and automatically generates an authentication ladder. The system for preventing fraudulent use of the FA device control program having an authentication ladder insertion determination unit for determining the number of authentication ladders to be inserted in accordance with the size of the control program and the free time calculated by the authentication ladder performance confirmation unit has been described.

(Embodiment 3)

In the present embodiment, the authentication ladder is filtered so that the user cannot see the authentication ladder inserted in the control program read from the PLC, and the number of steps calculated based on the authentication information for the control program edited by the user. This chapter describes the function to adjust the insertion position of the authentication ladder.

7 shows a functional configuration of the illegal use prevention system according to the present embodiment.

The illegal use prevention system shown in FIG. 7 filters the authentication ladder so that the user cannot see the authentication ladder inserted in the control program, and adjusts the insertion position of the authentication ladder after editing the control program.

In the engineering environment side PC 100, the control program read request part 21, the authentication ladder filtering process part 22, the authentication ladder insertion position adjustment process part 23, and the display part 30 are added.

The other elements are the same as those shown in FIG.

In addition, in this embodiment, the access request transmission process part 4 inputs from the PLC 200 the control program (synthesis program) in which the authentication ladder is inserted.

In this embodiment, the access request transmission processing unit 4 is an example of a program input unit.

In addition, like the first embodiment, the use of the control program other than the PLC 200 is not permitted.

The authentication ladder is the same as that shown in the first embodiment.

The authentication ladder generation random number storage section 8a stores the authentication ladder generation random number described in the first embodiment, and is an example of the random number storage section.

The serial ID storage unit 9a stores the serial ID of the PLC 200 described in the first embodiment, and is an example of the unique identification information storage unit.

The control program read request unit 21 receives a read instruction of the control program from the user and requests the access request transmission processor 4 to read the control program.

The authentication ladder filtering processing unit 22 specifies the insertion position of the authentication ladder in the control program read from the PLC 200 based on the authentication information generated by the authentication processing unit 10a, and the control program creating unit 2 controls the control program. Is displayed on the display unit 30, the control program is filtered (non-display setting) so as not to show the authentication ladder to the user.

That is, the authentication ladder filtering processing unit 22 authenticates the PLC 200 based on authentication information which is a hash value for the random number of the authentication ladder generation random number storage unit 8a and the serial ID of the serial ID storage unit 9a. According to the same algorithm as that of the ladder insertion position determination algorithm, the position of each authentication ladder is determined, and non-display setting is performed for each authentication ladder.

The authentication ladder filtering processing unit 22 is an example of the non-display setting unit.

The display unit 30 displays only the control program without displaying the authentication ladder based on the non-display setting by the authentication ladder filtering processing unit 22.

The authentication ladder insertion position adjustment processing unit 23 sets the insertion position (number of steps) of the authentication ladder calculated based on the authentication information after the control program is edited by the control program creation unit 2 to the position of the original step number. Adjust to insert.

That is, the authentication ladder insertion position adjustment processing unit 23 returns the position of the authentication ladder to the position before the change when the arrangement of any of the authentication ladders is changed as a result of the edit of the control program and the update of the control program. .

For example, in the example of FIG. 4 (b), when the user edits the control program, when A234, which was in the 234th step, is shifted to the 235th step position after the one, the authentication ladder insertion position adjustment processing unit 23 is performed. Returns A234 to the original 234 step position (the position before X15).

The authentication ladder insertion position adjustment processing unit 23 is an example of a position adjustment unit.

In the PLC 200, a control program read processing unit 24 is added.

The control program read processing unit 24 reads the control program (synthesis program) from the execution control program storage unit 15.

In addition, in the present embodiment, the access request reception processing unit 11 outputs the control program read by the control program reading processing unit 24 to the engineering environment side PC 100.

In the present embodiment, the access request reception processing unit 11 and the control program reading processing unit 24 correspond to a program output unit.

In addition, in FIG. 7, illustration of the element which is not directly related to the operation | movement which concerns on this embodiment in the PLC 200 is abbreviate | omitted.

However, the PLC 200 includes a control program write processing unit 12, an automatic authentication ladder generation processing unit 13, an authentication ladder insertion processing unit 14, a control program execution control unit 16, a dedicated device setting unit 17, and the like. It is assumed that the elements described in the first and second embodiments are included.

Next, the authentication performed when a control program read request is made when the security setting of the security setting unit 6a is made effective will be described.

When the control program read request unit 21 receives a read request of the control program stored in the PLC 200 from the input unit 1, the security setting of the security setting unit 6a is checked, and the PLC is set when the security setting is valid. In order to perform challenge response authentication with 200, the authentication processing unit 10a is required to generate a challenge value (random number).

The authentication processing unit 10a requests the random number generation processing unit 7 to generate a random number, and returns the received random number to the control program read request unit 21.

The control program read request unit 21 requests the access request transmission processing unit 4 to perform challenge response authentication with the PLC 200.

The access request transmission processing unit 4 transmits an authentication request and a challenge value (random number) to the access request reception processing unit.

The access request reception processing unit 11 that has received the authentication request transmits the challenge value received to the authentication processing unit 10b to instruct the generation of the response value.

The authentication processing unit 10a receives a request for generating a response value and stores a random number stored in the authentication ladder generation random number storage unit 8b, a serial ID stored in the serial ID storage unit 9b, and a random number received as a challenge value. As an input, a response value (hash value) is generated by the hash function, and the generated response value is returned to the access request reception processing unit 11.

The access request reception processing unit 11 returns the received response value to the access request transmission processing unit 4, and the access request transmission processing unit 4 having received the response value returns the response value to the control program read request unit 21.

The control program reading request unit 21 transmits the response value received to the authentication processing unit 10a, and the authentication processing unit 10a uses the same algorithm as that of the PLC 200 to the authentication ladder generation random number storage unit 8a. The hash value is generated by the hash function by inputting the stored random number, the serial ID stored in the serial ID storage unit 9a, and the challenge value just created, and compared with the response value to compare the result of the control program. Notify the read request unit.

If the comparison result is inconsistent, the control program read request unit 21 stops the read processing of the control program and notifies the user that the control program cannot be read from the PLC.

When the comparison results match, the control program read request unit 21 instructs the access request transmission processor 4 to read the control program.

The access request reception processing unit 11 instructs the control program read processing unit 24 to read the control program when receiving the read request of the control program.

The control program read processing unit 24 reads the control program from the execution control program storage unit 15 and returns it to the access request reception processing unit 11.

The control program read request unit 21 stores the control program read from the PLC 200 in the control program storage unit 3.

In this way, when the security setting is enabled, authentication is performed by using the association information between the control program and the PLC, and writing and reading processing of the control program is performed between the project and the PLC that do not have the same association information. Control not to do it.

This is for the purpose that the control program stored in the PLC cannot be easily read externally to create an illegal copy.

In addition, in this embodiment, although authentication process is performed at the time of a control program reading, authentication process is similarly performed also when the control program write process is performed.

In addition, in this embodiment, the authentication request is made only from the engineering environment side, but the authentication request is made to the engineering environment side PC 100 side when there is a request for access to the execution control program storage unit 15 at the PLC 200 side as well. You may also

Next, a description will be given of a process for filtering so that the authentication ladder inserted in the control program read from the PLC is not visible to the user.

When the user instructs display / edit of the control program stored in the control program storage unit 3 using the input unit 1, the authentication ladder filtering processing unit 22 generates the authentication generated by the authentication processing unit 10a. The information is acquired and the insertion position of the authentication ladder inserted into the control program is confirmed by the authentication ladder insertion processing unit 14 based on the obtained authentication information. (The number of steps is calculated from the authentication information to determine the insertion position of the authentication ladder. box).

The authentication ladder filtering processing unit 22 reads the control program from the control program storage unit 3, and sets the authentication ladder (authentication ladder illustrated in Fig. 4 (a)) to be executed only once and the calculated number of steps. The non-display setting is performed on the authentication ladder (the authentication ladder inserted in the specific number of steps in the control program: the authentication ladder illustrated in Fig. 4B).

When the control program preparation unit 2 displays the control program received from the authentication ladder filtering processing unit 22, the control program creation unit 2 checks the non-displayed location, and performs control that does not display the authentication ladder of the non-displayed location. And output to the display unit 30, and the display unit 30 displays only the control program without displaying the authentication ladder.

In addition, the authentication ladder insertion position adjustment processing unit 23 is an authentication ladder insertion position (number of steps) generated by addition or deletion of a command by a user with respect to a control program edited by the control program creation unit 2. ) Is returned to the original position based on the authentication information generated by the authentication processing unit 10a, and then the control program is stored in the control program storage unit 3.

As described above, according to the present embodiment, the authentication ladder is not shown to the user, thereby preventing the regular user from accidentally deleting or changing the authentication ladder, and the malicious user prevents the illegal use of the control program. This makes it difficult to prevent unauthorized use of the control program.

As mentioned above, in this embodiment, the control program memorize | stores the control program which received the read request of the control program stored in the PLC's execution control program storage part from the engineering environment, and gave the access request transmission processing part the instruction to read the control program. A control program reading request unit for storing the control program, an authentication ladder filtering processing unit for filtering to prevent the user from displaying the authentication ladder when the user displays / edits a control program in which the authentication ladder is inserted, and a control program preparing unit Reads the control program from the authentication ladder insertion position adjustment processing unit that executes a process of returning the authentication ladder inserted in accordance with the authentication information to the original position when the user edits the control program by the user. To execute processing Control the read processing program described illegal use prevention system of the FA device, the control program prepared.

(Fourth Embodiment)

In the present embodiment, the control program read from the PLC has a function of replacing the dedicated device of the authentication ladder inserted in the authentication ladder insertion processing unit 14 with the existing device so that the existence of the dedicated device is not known to the user. Explain.

8 shows a functional configuration of the illegal use prevention system according to the present embodiment.

In the illegal use prevention system of FIG. 8, the number of the dedicated device of the authentication ladder inserted in the control program is replaced with the number of the existing device according to the conversion rule set in advance in the conversion table.

Since each of the components of the engineering environment side PC 100 has been described in Embodiments 1 to 3, description thereof is omitted.

In the PLC 200, an authentication ladder conversion table storage unit 25 and an authentication ladder conversion processing unit 26 are added to the configuration of FIG. 7.

8, illustration of the element which is not directly related to the operation | movement which concerns on this embodiment in the PLC 200 is abbreviate | omitted.

However, the PLC 200 includes a control program write processing unit 12, an automatic authentication ladder generation processing unit 13, an authentication ladder insertion processing unit 14, a control program execution control unit 16, a dedicated device setting unit 17, and the like. It is assumed that the elements described in the first and second embodiments are included.

The authentication ladder conversion table storage unit 25 converts the dedicated device number of the authentication ladder inserted in the control program into the number of existing devices when a request is made to read the control program from the engineering environment side PC 100. The conversion table to be used is stored.

The authentication ladder conversion processing unit 26 executes a process of replacing the dedicated device number with an existing device number by using the conversion table stored in the authentication ladder conversion table storage unit 25.

As described above, the device number of the dedicated device is different from the device number of the target device (in the example of Embodiment 1, the dedicated device number starts with "A", the target device number is "X", Start with "Y", "E").

For this reason, when the output instruction of the control program (synthesis program) stored in the control program storage part 15 for execution was received from the engineering environment side PC 100, the authentication ladder conversion processing part 26 of the authentication ladder conversion processing part 26 The dedicated device number is changed to the same numbering system as the target device number (the dedicated device number is started with "X", for example).

The authentication ladder conversion processing unit 26 is an example of a device number changing unit.

In addition, in the present embodiment, the access request reception processing unit 11 (program output unit) includes a control program (synthesis program) containing the dedicated device number after being changed by the authentication ladder conversion processing unit 26 (the engineering environment side PC). To 100).

Next, when the security setting is enabled, a process of replacing the dedicated device number of the authentication ladder with the existing device number when the control program is read out will be described.

When the control program read processing unit 24 receives a read request of the control program from the engineering environment side PC 100, the control program read processing unit 24 checks the security setting of the security setting unit 6b, and the security setting is valid. Next, the authentication ladder conversion processing unit 26 requests the replacement of the dedicated device of the authentication ladder inserted in the control program read from the execution control program storage unit 15 into the existing device.

Based on the conversion table set in the authentication ladder conversion table storage section 25, the authentication ladder conversion processing section 26 that receives the conversion request from the dedicated device to the existing device uses the dedicated device that is used as the authentication ladder. Replace with (X device or Y device).

For example, the dedicated device A234 converts to an existing device X234.

When converting to an existing device, it is not necessary to convert to an X device, but an existing device may be used.

The device number need not be the same as the dedicated device but may be a device number that can be used as an existing device that has been replaced.

In addition, on the engineering environment side which reads out the control program which replaced the dedicated device by the existing device, as described in Embodiment 3, since an authentication ladder is filtered and an authentication ladder is not shown to a user, a conversion table is necessary. none.

As described above, according to the present embodiment, by replacing the dedicated device of the authentication ladder inserted in the control program read by the engineering environment with an existing device, for example, a malicious program reads a control program read by a malicious user. And a tool for interpreting the code, it is not possible to easily know that a device which is not used in the conventional control program is being used, and it is difficult to interpret the authentication processing method.

That is, according to the third embodiment, since the authentication ladder is hidden, the dedicated device number is not displayed. However, when the above-described tool is used, the existence of the dedicated device number is revealed even if it is set to non-display. There is. In this embodiment, even when such a tool is used, since the dedicated device number has the same number system as the normal device number, it is possible to avoid the identification of the dedicated device number.

As described above, in the present embodiment, an authentication ladder conversion processing unit and an authentication ladder conversion processing unit that receive instructions from the control program reading processing unit and replace the dedicated device of the authentication ladder with an existing device when the control program reading in the engineering environment is requested. In the following, a system for preventing unauthorized use of an FA device control program having an authentication ladder conversion table storage unit for storing a conversion table used to replace a dedicated device for an authentication ladder with an existing device has been described.

(Embodiment 5)

In this embodiment, every time the control program is read from the PLC, the authentication information is regenerated using the value of the counter provided in the PLC, and the authentication ladder is also regenerated to replace the authentication ladder inserted in the control program before engineering. The function to transmit to the environment is explained.

9 shows a functional configuration of the illegal use prevention system according to the present embodiment.

In the illegal use prevention system of FIG. 9, whenever the control program is read from the PLC 200, the authentication ladder is regenerated based on the authentication information regenerated using the counter value provided in the PLC 200. Replacement with the authentication ladder inserted in the module is performed.

In FIG. 9, the operation history storage unit 27 is added to the engineering environment side PC 100.

The operation history storage unit 27 stores operation contents such as a function name executed by the user on the engineering environment side PC 100, a time stamp and error information when executed, and the like.

The operation history storage unit 27 is an example of the input count counter.

In addition, since the component of the engineering environment side PC 100 other than the operation history storage part 27 is what was demonstrated in Embodiment 1-3, description is abbreviate | omitted.

In addition, although the display part 30 is abbreviate | omitted by the problem of the space on drawing, it is assumed that the display part 30 exists in the engineering environment side PC 100 of FIG.

In the PLC 200, an authentication ladder deletion processing unit 28 and a counter processing unit 29 are added.

The authentication ladder deletion processing unit 28 deletes the authentication ladder inserted in the control program.

More specifically, when the access request reception processing unit 11 (program output unit) outputs a control program (synthesis program) in which an authentication ladder is inserted from the engineering environment side PC 100, which is an external device, The control program (synthesis program) is output to the engineering environment side PC 100, but at the time of output to the engineering environment side PC 100, the authentication ladder is deleted from the control program (synthesis program).

The authentication ladder deletion processing unit 28 is an example of the deletion processing unit.

The counter processing unit 29 counts up the value of the counter provided in the PLC 200 and stores the counted up value each time the request for reading the control program from the engineering environment is received.

That is, each time the control program (synthesis program) is output to the engineering environment side PC 100 by the access request reception processing unit 11, the number of outputs is counted.

The counter processor 29 is an output count counter.

In the present embodiment, the authentication ladder automatic generation processing unit 13 (authentication program generation unit) is output by the access request reception processing unit 11 to the engineering environment side PC 100 when the control program (synthesis program) is output. Each time, based on the serial ID of the serial ID storage unit 9b, the count value of the counter processing unit 29, and the random number of the random number storage unit 8b for authentication ladder generation, the device number of the dedicated device is newly selected, and the new dedicated unit is selected. A new authentication ladder including the device number is generated, and a new insertion position in the control program after the deletion processing by the authentication ladder deletion processing unit 28 is determined for each new authentication ladder generated.

Then, the authentication ladder insertion processing unit 14 (program synthesizing unit) inserts each new authentication ladder into the control program at the new insertion position determined by the authentication ladder automatic generation processing unit 13 to make a new synthesis program.

In addition, in FIG. 9, illustration of the element which is not directly related to the operation | movement which concerns on this embodiment in the PLC 200 is abbreviate | omitted.

However, it is assumed that the PLC 200 includes the elements described in the first to third embodiments, such as the control program write processing unit 12, the control program execution control unit 16, and the dedicated device setting unit 17.

Next, the operation according to the present embodiment will be described.

First, the operation of the PLC 200 side will be described.

In Embodiment 1, authentication information is generated by a hash function by inputting two pieces of information, a random number generated by the engineering environment side PC 100 and a serial ID of the PLC 200 at the first writing of the control program to the PLC. there was.

In this embodiment, authentication information is generated using the value of the counter of the counter processing unit 29 in addition to the above two pieces of information, and an authentication ladder is generated from the generated authentication information.

The counter of the counter processing part 29 counts up every time the control program read request is received from the engineering environment side PC 100.

As for the value of this counter, the initial value 0 is set at the time of the first write of a control program, and the value of the counter at the time of generating authentication information at the time of a first write is used.

Subsequently, upon receiving a request for reading the control program from the engineering environment side PC 100, the authentication ladder automatic generation processing unit 13 instructs the counter processing unit 29 to count up, and the counter processing unit 29 according to the instruction. Counts up the value of the counter by one.

The control program read processing unit 24 that receives the request for reading the control program from the engineering environment side PC 100 instructs the authentication ladder automatic generation processing unit 13 to regenerate the authentication ladder.

The authentication ladder automatic generation processing unit 13 receives the regeneration request of the authentication ladder and instructs the authentication processing unit 10b to generate authentication information.

The authentication processing unit 10b hashes the random number stored in the authentication ladder generation random number storage unit 8b, the serial ID stored in the serial ID storage unit 9b, and the count value stored in the counter processing unit 29. The operation is performed to generate authentication information, which is returned to the authentication ladder automatic generation processing unit 13.

The authentication ladder automatic generation processing unit 13 transfers the received authentication information and the control program to the authentication ladder deletion processing unit 28.

The authentication ladder deletion processing unit 28 determines the insertion position of the authentication ladder currently inserted into the control program based on the received authentication information, deletes the authentication ladder, and automatically generates the control program for deleting the authentication ladder. Return).

The authentication ladder automatic generation processing unit 13 instructs the counter processing unit 29 to count up, and the counter processing unit 29 counts up and holds the counter value.

The authentication ladder automatic generation processing unit 13 requests the authentication processing unit 10b to generate the authentication information again, and the authentication processing unit 10b regenerates the authentication information using the counted up counter value, and reproduces the reproduced authentication information. It returns to the authentication ladder automatic generation processing unit 13.

The authentication ladder automatic generation processing unit 13 automatically generates the authentication ladder from the regenerated authentication information (specifies the insertion position of each authentication ladder), and generates the authentication ladder and the authentication ladder by the authentication ladder deletion processing unit 28. The deleted control program is transferred to the authentication ladder insertion processing unit 14.

Then, the authentication ladder automatic generation processing unit 13 instructs the reinsertion of the regenerated authentication ladder into the control program, and the authentication ladder insertion processing unit 14 reinserts the authentication ladder.

The control program read processing unit 24 transmits the control program in which the authentication ladder has been reinserted to the engineering environment via the access request reception processing unit 11.

Next, the operation on the engineering environment side PC 100 side will be described.

The control program read request unit 21 having received the control program is stored in the control program storage unit 3.

When the user instructs display / edit of the control program stored in the control program storage unit 3 using the input unit 1, the authentication ladder filtering processing unit 22 causes the authentication processing unit 10a to generate the authentication information. Request.

The authentication processing unit 10a which has received a request for generating authentication information performs the number of times of reading processing of the control program from the PLC 200 from the operation history stored in the operation history storage unit 27 (the number of times of successful reading). Only).

Next, the authentication processing unit 10a calculates the calculated value (this value is the same as the value of the counter held by the counter processing unit 29 of the PLC) and the random number stored in the authentication ladder generation random number storage unit 8a. And the authentication information is calculated from the serial ID stored in the serial ID storage unit 9a and returned to the authentication ladder filtering processing unit 22.

The authentication ladder filtering processing unit 22 confirms the insertion position of the authentication ladder inserted into the control program by the authentication ladder insertion processing unit 14 based on the obtained authentication information (the number of steps is calculated from the authentication information to determine the authentication ladder. The insertion position).

The authentication ladder filtering processing section 22 reads the control program from the control program storage section 3 and locates at the authentication ladder (the authentication ladder illustrated in Fig. 4A) set to be executed only once and the calculated number of steps. The non-display setting is performed for the authentication ladder (the authentication ladder inserted in the specific number of steps in the control program: the authentication ladder illustrated in Fig. 4B).

When the control program preparation unit 2 displays the control program received from the authentication ladder filtering processing unit 22, the control program creation unit 2 checks the non-displayed location, and performs control not to display the authentication ladder of the non-displayed location. It outputs to the display part 30, and the display part 30 displays only a control program, without displaying an authentication ladder.

In addition, the authentication ladder insertion position adjustment processing unit 23 (position adjustment unit) is the authentication ladder insertion position generated by adding or deleting a command by the user to the control program edited by the control program creation unit 2 ( The number of steps) is returned to the original position based on the authentication information generated by the authentication processing unit 10a, and then the control program is stored in the control program storage unit 3.

As described above, in this embodiment, the counter is counted up each time a read request of the control program stored in the execution control program storage unit 15 is received, and the value of the counter is used to determine the authentication information and the authentication information. On the basis of this, the authentication ladder is regenerated and replaced with the authentication ladder inserted in the control program.

By these processes, the control programs read out from the engineering environment side PC 100 side are different each time, which makes it difficult to analyze the authentication process by a malicious user.

Further, even if a malicious user can copy the control program to another PLC, for example, since authentication information is generated by using a counter value unique to each PLC, unauthorized use of the control program can be further prevented.

Normally, the control program is written to the PLC to confirm the actual operation. According to the result, the program or parameter setting is adjusted while repeating writing / reading of the control program with the engineering environment. As a result, it is thought that the value of other PLCs and counters is the same.

As mentioned above, in this embodiment, the operation history storage part which stores the operation history of the function which the user performed on the engineering environment, the authentication ladder deletion processing part which once deletes from a control program in order to reinsert the authentication ladder inserted in the control program, and The system for preventing misuse of the FA device control program having a counter processing unit for counting up the value of the counter and storing the counted up value whenever a read request of the control program in the engineering environment is received has been described.

1: input unit, 2: control program creating unit, 3: control program storage unit, 4: access request transmission processing unit, 5: control program writing request unit, 6: security setting unit, 7: random number generation processing unit, 8: authentication ladder generation Random number storage unit, 9: serial ID storage unit, 10: authentication processing unit, 11: access request receiving processing unit, 12: control program writing processing unit, 13: authentication ladder automatic generation processing unit, 14: authentication ladder insertion processing unit, 15: execution Control program storage unit, 16: control program execution control unit, 17: dedicated device setting unit, 18: execution restriction time storage unit, 19: authentication ladder performance checking unit, 20: authentication ladder insertion determination unit, 21: control program reading request unit 22: authentication ladder filtering processing unit, 23: authentication ladder insertion position adjusting processing unit, 24: control program reading processing unit, 25: authentication ladder conversion table storage unit, 26: authentication ladder conversion processing unit, 27: operation history storage unit, 28: authentication Rae Deletion processing section, 29: Counter processing unit, 30: display portion, 100: side engineering environment, PC, 200: PLC

Claims (14)

As a control device,
A unique identification information storage section for storing unique identification information uniquely set in the control device;
A program input unit which contains a number of a target device to be controlled by the control device and inputs a ladder program which is not permitted to be used by a device other than the control device as a main program;
An authentication program generation unit for generating a ladder program as an authentication program that prevents the use of the main program by devices other than the control device based on the unique identification information;
A program synthesizing unit synthesizing the main program and the authentication program into a synthesis program;
A program storage unit for storing the synthesized program
Has,
The authentication program generation unit,
A pseudo device number that pseudonyms the target device number is managed as the device number for authentication,
Select one or more authentication device numbers based on the unique identification information,
Generating a ladder program including the selected selective authentication device number as the authentication program,
The authentication program generated by the authentication program generation unit,
When executed together with the main program as the synthesizing program, the selection authentication device number is selected based on the unique identification information, and the predetermined processing specified in advance for each of the selection authentication devices corresponding to the selection authentication device number. Is performed normally, the main program is operated normally,
When executed together with the main program as the synthesized program, when the setting processing is not performed for each of the selective authentication devices, the operation of the main program is stopped because it does not operate normally.
Control device characterized in that.
The method of claim 1,
The control device,
A plurality of authentication devices are managed in correspondence with respective authentication device numbers, and at the time of execution of the synthesized program stored in the program storage unit, independent of the selection operation of the authentication program generation unit, based on the unique identification information. A setting processing unit which selects one or more authentication device numbers, and executes predetermined setting processing for each of the selection authentication devices corresponding to the selected selection authentication device number;
A program execution unit that executes a synthesized program stored in the program storage unit after setting processing is performed for each of the selection authentication devices by the setting processing unit;
It further has a control device.
The method of claim 2,
The control device,
A random number storage unit for storing random numbers,
Prior to the generation of the authentication program by the authentication program generating unit, one-way operation is performed on the random number stored in the random number storage unit and the unique identification information stored in the unique identification information storage unit. Prior to the setting processing, the one-way operation unit performs one-way operation on the random number stored in the random number storage unit and the unique identification information stored in the unique identification information storage unit.
With more
The authentication program generation unit selects one or more authentication device numbers based on the one-way operation value by the one-way operation unit, and generates an authentication program including the selected selected authentication device number.
The setting processing unit selects one or more authentication device numbers on the basis of the one-way operation value by the one-way operation unit, and preconfigured setting processing for each of the selection authentication devices corresponding to the selected selection authentication device number. Will run
Control device characterized in that.
The method according to claim 2 or 3,
The authentication program generating unit operates normally when the setting processing for turning on the selection authentication device from the off state is performed, and the main program operates normally, and setting processing for turning on the selection authentication device from the off state. If it is not performed, a ladder program is generated as an authentication program that does not operate normally and stops the operation of the main program.
The setting processing unit executes setting processing for setting the device for selective authentication to an on state from the off state.
Control device characterized in that.
The method according to any one of claims 1 to 3,
The authentication program generation unit,
Select two or more authentication device numbers,
A head authentication program including all of the selected selective authentication device numbers and placed at the head of the main program; and each of the selected authentication device numbers is inserted into a plurality of insertion positions in the main program. Create at least one of two or more embedded authentication programs,
The program synthesizing unit places the head authentication program at the head of the main program, and inserts the two or more insertion verification programs into a plurality of insertion positions in the main program.
Control device characterized in that.
The method according to any one of claims 1 to 3,
The control device,
An allowable time storage section for storing, as an allowable time, an allowable time range for the execution time of the synthesized program in which the main program and the authentication program are combined;
A time estimating unit for predicting execution time of a main program inputted by the program input unit;
A number determination unit that determines the number of device numbers for authentication to be included in the authentication program based on the estimated time required by the time estimation unit and the allowable time.
With more
Wherein the authentication program generation unit selects an authentication device number for the number determined by the number determination unit
Control device characterized in that.
The method according to any one of claims 1 to 3,
The control device determines whether the program size of the main program input by the program input unit is greater than or equal to a predetermined size, and if the program size of the main program is less than the predetermined size, authenticate the authentication program generation unit. And a program size determination unit for instructing generation of an authentication program to the authentication program generation unit if the generation of the program is suspended and the program size of the main program is equal to or larger than the predetermined size.
The method of claim 7, wherein
The authentication program generation unit,
Select two or more authentication device numbers,
Generating two or more insertion authentication programs each containing any one of a device for selective authentication, and determining an insertion position in the main program for each insertion authentication program according to a predetermined insertion position determination algorithm,
The program synthesizing unit inserts each of the insertion authentication programs into the main program at the insertion position determined by the authentication program generating unit.
The program size determination unit,
Prior to generation of the insertion authentication program by the authentication program generating unit, based on the program size of the main program, whether the insertion position of the insertion authentication program determined according to the insertion positioning algorithm is concentrated on a specific part of the main program. Judge whether or not,
When the insertion position of the insertion authentication program concentrates on a specific part of the main program, as an algorithm other than the insertion positioning algorithm, the insertion authentication program according to an algorithm in which the insertion position of the insertion authentication program is more distributed in the main program. Instructing the authentication program generator to determine the insertion position of the
Control device characterized in that.
The method according to any one of claims 1, 2, 3, 8,
The authentication program generation unit generates an authentication program including an authentication device number different from the target device in a number system,
The control device,
When the instruction for outputting the synthesized program stored in the program storage unit comes from an external device, the device having the same number system as the device number of the target device is selected as the device number for selective authentication included in the authentication program in the synthesized program. A device number changing unit to change the number;
A program output unit for outputting a synthesized program including the device number after the change by the device number change unit to the external device in the authentication program;
It further has a control device.
The method according to any one of claims 1, 2, 3, 8,
The authentication program generation unit,
Select two or more authentication device numbers,
Generating two or more insertion authentication programs each including any one of a device for selective authentication, and determining an insertion position in the main program for each insertion authentication program;
The program synthesizing unit inserts each of the insertion authentication programs into the main program at the insertion position determined by the authentication program generating unit to be a synthesis program.
The control device,
A program output unit for outputting the synthesized program to the external device when the instruction to output the synthesized program is from an external device;
A deletion processing unit for deleting the two or more insertion authentication programs from the synthesis program each time the synthesis program is output to the external device by the program output unit;
An output count counting unit for counting the number of outputs each time the synthesized program is output to the external device by the program outputting unit;
With more
The authentication program generating unit newly sets two or more authentication device numbers on the basis of the unique identification information and the count value of the output counting unit each time the synthesis program is output to the external device by the program output unit. Select and generate two or more new insertion authentication programs each containing one of the new selective authentication device numbers, and for each new insertion authentication program generated, insert a new insertion position in the main program after the deletion processing by the deletion processing unit. Decide,
The program synthesizing unit inserts each of the new insertion authentication programs into the main program at a new insertion position determined by the authentication program generating unit to form a new synthesis program.
Control device characterized in that.
A management device for managing a control device,
In the control apparatus, in order to prevent the use of the main program used for the control in the control apparatus and the main program by the apparatus other than the control apparatus, which are not permitted to be used by devices other than the control apparatus. A program input unit which inputs, from the control apparatus, a synthesis program into which the generated authentication program is synthesized;
A non-display setting unit for extracting the authentication program from the synthesis program and performing non-display setting for the authentication program;
A display unit for displaying only the main program without displaying the authentication program based on the non-display setting by the non-display setting unit;
Management device characterized in that it has a.
The method of claim 11,
The management apparatus includes:
A unique identification information storage section for storing unique identification information uniquely set in the control device;
Random number memory to remember random numbers
With more
The program input unit is a synthesized program in which each of a plurality of authentication programs is arranged at a predetermined position in the main program, and is authenticated using the unique identification information and the random number in accordance with a predetermined decision algorithm in the control apparatus. Input the synthesis program which each authentication program is arrange | positioned at the determined position every time,
The non-display setting unit determines the position of each authentication program by using the unique identification information of the unique identification information storage unit and the random number of the random number storage unit according to the same decision algorithm as that of the control device. To make non-display settings for the program
Management device characterized in that.
The method of claim 11,
The management apparatus includes:
A unique identification information storage section for storing unique identification information uniquely set in the control device;
A random number storage unit for storing random numbers,
An input number counting unit for counting the number of times of input each time the synthesis program is input from the control device
With more
The program input unit is a synthesized program in which each of a plurality of authentication programs is arranged at a predetermined position in the main program, and is provided from the unique identification information, the random number, and the control device in accordance with a predetermined decision algorithm in the control device. Inputting a synthesis program in which each authentication program is arranged at a position determined for each authentication program by using the number of outputs of the synthesis program to the management apparatus,
The non-display setting unit uses the unique identification information of the unique identification information storage unit, the random number of the random number storage unit, and the count value of the input count counter according to the same determination algorithm as that of the control device. Determining the location of programs and setting non-display settings for each authentication program
Management device characterized in that. The method according to claim 12 or 13,
The management apparatus further includes a position adjusting unit for returning the position of the authentication program to the position before the change when the arrangement of any one of the authentication programs is changed as a result of the update of the synthesis program in the management apparatus. Management device.

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