JP2020096384A - Information processing apparatus, information processing method, and program - Google Patents

Abstract

To provide a monitoring device capable of improving a hardware security function of a product using a PUF.SOLUTION: A monitoring device 10a included in a monitoring system 1 configuring a distributed ledger system and monitoring a monitoring target device 22a includes a circuit information distribution unit that distributes circuit information for forming a predetermined PUF circuit to the monitored device 22a, a transmission processing unit that transmits a predetermined challenge value to the monitoring target device 22a that has distributed the circuit information, a reception processing unit that receives a response value corresponding to the challenge value of the PUF circuit formed in the monitoring target device 22a, and an authentication processing unit that authenticates the monitoring target device 22a on the basis of input/output correspondence information of the PUF circuit formed in the monitoring target device 22a and the received response value.SELECTED DRAWING: Figure 2

Description

The present invention relates to an information processing device, an information processing method, and a program.

As a method of protecting embedded software, protection by encryption using a TPM (Trusted Platform Module) and a method of erasing software by detecting an environmental change have been proposed. Also, a physical quantity such as a manufacturing variation of a semiconductor chip or a difference in physical characteristics, which is called a Physically Unclonable Function (PUF), is output as an eigenvalue of the semiconductor chip, and authenticity determination of the semiconductor chip or its mounted device is performed. It has been proposed to use it for security functions of electronic device hardware such as authentication processing and encryption processing (see, for example, Patent Document 1).

Japanese Patent No. 5499358

As one mode of the physical copy difficulty function (hereinafter, also referred to as “PUF”), a predetermined circuit (hereinafter, also referred to as “PUF circuit”) is formed (program) in an FPGA (Field-Programmable Gate Array). However, an arbiter PUF (Arbiter PUF), a glitch PUF (Glitch PUF), and the like, which utilize a signal delay difference specific to the PUF circuit, are known.

In order to use the arbiter PUF and the glitch PUF to improve the hardware security function, unique input/output correspondence information (challenge response pair; CRP) for the PUF circuit is acquired in advance before product shipment. However, it is necessary to keep a record. In this case, considering the possibility that the pre-recorded input/output correspondence information is falsified, there is concern about the improvement of the hardware security function using the PUF.

An object of the present invention is to provide an information processing device, an information processing method, and a program capable of improving a hardware security function using a PUF.

According to the first aspect of the present invention, the monitoring device is one of a plurality of nodes that configure the distributed ledger system, and is a monitoring device that monitors a predetermined monitoring target device, the distributed ledger. A circuit information distribution unit that distributes circuit information for forming a predetermined PUF circuit to the monitored device, which is information registered in advance in the system, and a predetermined circuit for the monitored device that has distributed the circuit information. A transmission processing unit that transmits a challenge value, a reception processing unit that receives a response value corresponding to the challenge value of the PUF circuit formed in the monitoring target device, and information registered in advance in the distributed ledger system. An authentication processing unit that authenticates the monitoring target device based on the input/output correspondence information of the PUF circuit formed in the monitoring target device and the received response value.

Further, according to the second aspect of the present invention, the authentication processing unit further authenticates the device to be monitored based on a result of an agreement forming process by a plurality of other nodes configuring the distributed ledger system. I do.

Further, according to the third aspect of the present invention, the circuit information distribution unit registers in advance in the distributed ledger system when an inquiry about a hash value of the distributed circuit information is received from the monitored device. The calculated hash value of the circuit information is transmitted.

Further, according to the fourth aspect of the present invention, a plurality of types of challenge values are transmitted to the monitoring target device, and a response value corresponding to each challenge value is received from the monitoring target device, and the monitoring target device is received. An input/output correspondence information registration unit that creates input/output correspondence information of the PUF circuit formed in 1 above and registers it in the distributed ledger system is further provided.

Further, according to the fifth aspect of the present invention, a mutual authentication unit that performs mutual authentication with the monitoring target device based on a common key registered in advance is further provided.

According to a sixth aspect of the present invention, a monitoring system includes a plurality of monitoring devices according to any one of the first to fifth aspects, and the plurality of monitoring devices are communicably connected to each other. Configuring the distributed ledger system.

Further, according to the seventh aspect of the present invention, the information processing device makes a request for circuit information to the monitoring device when the PUF circuit is not formed, and based on the circuit information received from the monitoring device. And a device authentication requesting unit for making an authentication request to the monitoring device when the PUF circuit is formed. The device authentication requesting unit includes the device authentication requesting unit. The challenge value received from the monitoring device is input to the PUF circuit as a response to, and the response value that is the output result is returned to the monitoring device.

Further, according to the eighth aspect of the present invention, the information processing apparatus further includes a decryption processing unit that decrypts a control program encrypted in advance when the authentication request is received from the monitoring apparatus. Prepare

Further, according to the ninth aspect of the present invention, the device authentication requesting unit erases the control program when the authentication request does not result in authentication from the monitoring device.

Further, according to the tenth aspect of the present invention, the monitoring method is a monitoring method for monitoring a predetermined monitoring target device by using a monitoring device which is one of a plurality of nodes constituting the distributed ledger system. And distributing circuit information for forming a PUF circuit to the monitored device, which is information registered in advance in the distributed ledger system, and a predetermined process for the monitored device to which the circuit information is distributed. And a response value corresponding to the challenge value of the PUF circuit formed in the monitored device, and information pre-registered in the distributed ledger system. And a step of authenticating the monitoring target device based on the input/output correspondence information of the PUF circuit formed in the monitoring target device and the received response value.

Further, according to an eleventh aspect of the present invention, the program is one of a plurality of nodes configuring the distributed ledger system, and a monitoring device for monitoring a predetermined monitoring target device is the distributed ledger system. Circuit information distribution unit that distributes circuit information for forming a PUF circuit to the monitoring target device, which is information registered in advance, and transmits a predetermined challenge value toward the monitoring target device that has distributed the circuit information. A transmission processing unit, a reception processing unit that receives a response value corresponding to the challenge value of the PUF circuit formed in the monitoring target device, and information that is registered in advance in the distributed ledger system and that is the monitoring target. Based on the input/output correspondence information of the PUF circuit formed in the device and the received response value, the device functions as an authentication processing unit that authenticates the device to be monitored.

According to each of the above aspects of the invention, it is possible to enhance the reliability of authenticity determination of a product using a PUF.

It is a figure which shows the whole structure of the monitoring system which concerns on 1st Embodiment. It is a figure which shows the structure of the monitoring system and embedded system which concern on 1st Embodiment. It is a figure which shows the function structure of the monitoring apparatus which concerns on 1st Embodiment. It is a figure which shows the function structure of the monitoring target apparatus which concerns on 1st Embodiment. It is a figure which shows the process flow of the mutual authentication phase performed between the monitoring apparatus and monitoring target apparatus which concern on 1st Embodiment. It is a figure which shows the process flow of the circuit information distribution phase performed between the monitoring apparatus and the monitoring target apparatus which concern on 1st Embodiment. It is a figure which shows the processing flow of the apparatus authentication phase performed between the monitoring apparatus and the monitoring target apparatus which concern on 1st Embodiment. It is a figure which shows the data structure of the 1st distributed ledger recorded on the monitoring apparatus which concerns on 1st Embodiment. It is a figure which shows the data structure of the input/output correspondence information recorded on the monitoring apparatus which concerns on 1st Embodiment. It is a figure which shows the data structure of the 2nd distributed ledger recorded on the monitoring apparatus which concerns on 1st Embodiment. It is a figure which shows the processing flow of the monitoring target apparatus which concerns on 1st Embodiment. It is a figure which shows the processing flow of the monitoring target apparatus which concerns on 1st Embodiment. It is a figure which shows the processing flow of the monitoring target apparatus which concerns on 2nd Embodiment. It is a figure which shows the processing flow of the monitoring target apparatus which concerns on 3rd Embodiment. It is a figure which shows the data structure of the input/output correspondence information recorded on the monitoring apparatus which concerns on 4th Embodiment. It is a figure which shows the function structure of the monitoring apparatus which concerns on 5th Embodiment. It is a figure which shows the processing flow of the new CRP registration phase performed between the monitoring apparatus and monitoring object apparatus which concern on 5th Embodiment.

<First Embodiment>
Hereinafter, the monitoring system and the monitoring target device according to the first embodiment will be described with reference to FIGS. 1 to 11B.

(Overall structure of monitoring system)
FIG. 1 is a diagram showing an overall configuration of a monitoring system according to the first embodiment.
The monitoring system 1 shown in FIG. 1 is a system for monitoring various embedded systems 2. Specifically, the monitoring system 1 is communicably connected to the embedded system 2 and performs authentication (verification of validity) of products (a logic solver, various IO devices, etc., which will be described later) configuring the embedded system 2.

As shown in FIG. 1, a plurality of monitoring devices 10 are provided.
The plurality of monitoring devices 10 are communicatively connected to each other through a wide area communication network (for example, an internet line). The plurality of monitoring devices 10 perform P2P (Peer to Peer) communication, for example.

The monitoring system 1 constitutes a distributed ledger system, and the plurality of monitoring devices 10 each function as a node of the distributed ledger system. In the configuration of the distributed ledger system, the information groups stored by the monitoring system 1 are independently held by each of the monitoring devices 10 as nodes, so that the information groups can be distributed and managed. Specifically, each monitoring device 10 stores the information group requested to be registered from the outside and registers (records) the information group as a new block in the distributed ledger system through a predetermined consensus algorithm. .. When a new block is registered in one node (monitoring device 10), it is similarly registered in all other nodes (monitoring device 10). The newly registered block includes information (hash value) uniquely determined from the contents of the previously registered block. As a result, it is possible to enhance the tamper resistance of the registered information group.

The embedded system 2 is a monitoring target of the monitoring system 1.
The embedded system 2 according to this embodiment is, for example, an embedded system that controls a gas turbine, a steam turbine, a boiler, or the like installed in a power plant or the like.
The embedded system 2 is constructed by combining a plurality of products (for example, logic solver, IO device, etc.). Each product that builds the embedded system 2 is sequentially added and updated according to the operation mode of the control target (gas turbine or the like). If the newly added or updated product is a fraudulent product (counterfeit), the entire embedded system 2 is exposed to the threat. Therefore, the monitoring system 1 performs authentication (verification of validity) of a product that is newly added or updated in each embedded system 2.
The embedded system 2 to which the monitoring system 1 is applied is not limited to a gas turbine, a steam turbine, or a boiler whose control target is, for example, an ITS (Intelligent Transport Systems), a cooling/heating system (a large refrigerator, an air conditioner). ), a vehicle (railway, automobile, construction machine, etc.) may be a control target.

(Configuration of monitoring system and embedded system)
FIG. 2 is a diagram showing the configurations of the monitoring system and the embedded system according to the first embodiment.
As shown in FIG. 2, the monitoring system 1 and the embedded system 2 are communicably connected to each other through a network adapter (NA) which is a network relay device.
The embedded system 2a shown in FIG. 2 is one of the plurality of embedded systems 2 to be monitored by the monitoring system 1. The embedded system 2a is, for example, an embedded system that controls a gas turbine.
The monitoring device 10a, which is one node of the monitoring system 1, is directly communicatively connected to the embedded system 2a and is set as a monitoring target. The other monitoring device 10b different from the monitoring device 10a does not directly monitor the embedded system 2a, but is directly connected to another unillustrated embedded system 2 for communication and makes each of them a monitoring target.

As shown in FIG. 2, the embedded system 2 includes an operator station (OPS) 20, an engineering maintenance station (EMS) 21, a logic solver (LS) 22, and an IO device (IO) 23.

The OPS 20 is a device for an operator to grasp the state of a device to be controlled (gas turbine) and perform control (valve opening/closing control, etc.).
The EMS 21 is a device for creating a control program and installing it in a control arithmetic device (a logic solver 22 described later).
The logic solver 22 is a core device that performs control calculation of the gas turbine. The logic solver 22 controls inputs/outputs and states of valves, sensors, etc. according to a control program. As shown in FIG. 2, a plurality of LSs 22 are connected in parallel to make them redundant.
The IO device 23 is an IO device (various sensors, actuators, etc.) attached to the gas turbine. The plurality of IO devices 23 are connected to the logic solver 22 via an IO scanner, an IO network, and an IO adapter. The IO scanner is a communication relay device for connecting the IO network and the logic solver 22, and the IO adapter is a communication relay device for the IO network.
The logic solver 22 and the IO device 23 according to this embodiment are one aspect of an information processing device that operates according to a predetermined control program.

The flow of processing when a logic solver 22a is newly added to the embedded system 2a will be described below. Here, the newly added logic solver 22a is also referred to as a monitored device 22a in the following description.

(Functional configuration of monitoring device)
FIG. 3 is a diagram showing a functional configuration of the monitoring device according to the first embodiment.
The configuration of the monitoring device 10a illustrated in FIG. 3 is the same for the other monitoring devices 10b included in the monitoring system 1.

As shown in FIG. 3, the monitoring device 10a includes a CPU 100, a ROM 101, a RAM 102, a communication interface 103, and a recording medium 104.

The CPU 100 is a processor that controls the entire operation of the monitoring device 10a. The CPU 100 performs various functions described below by operating according to a program prepared in advance.
The ROM 101 is a non-rewritable non-volatile memory. In the ROM 101 according to this embodiment, a common key SK for realizing the common key cryptosystem is recorded in advance.
The RAM 102 is a rewritable volatile memory. The RAM 102 is also referred to as a main storage device, and is loaded with programs for the CPU 100 to perform various functions and operate.
The communication interface 103 is an interface for communicating with another monitoring device 10a and the embedded system 2 to be monitored through a wide area communication network. In the present embodiment, the mode of communication (wired or wireless, global network or local network, etc.) via the communication interface 103 is not particularly limited.
The recording medium 104 is a mass storage device (nonvolatile memory) built in the monitoring device 10a, and is, for example, an HDD (Hard Disk Drive), an SSD (Solid State Drive), or the like. The recording medium 104 is also called an auxiliary storage device, and stores a database of the distributed ledger system (hereinafter, also referred to as “distributed ledger”) configured by the monitoring system 1.

By operating according to a predetermined program, the CPU 100 exhibits the functions of the mutual authentication reception unit 1000, the circuit information distribution unit 1001, and the device authentication unit 1002.
The mutual authentication receiving unit 1000 receives the mutual authentication processing from the monitoring target device 22a newly added to the embedded system 2. The “mutual authentication processing” will be described later.
The circuit information distribution unit 1001 distributes circuit information to the monitoring target device 22a newly added to the embedded system 2. The “circuit information” is information for forming (programming) a predetermined PUF (Physically Unclonable Function) circuit and a predetermined encryption key generation circuit in an FPGA (described later) included in the monitoring target device 22a. The circuit information (and its hash value) is registered in advance in the distributed ledger of the distributed ledger system configured by the monitoring system 1.
The device authentication unit 1002 performs an authentication (validity verification) process on the monitoring target device 22a to which the circuit information distribution unit 1001 has distributed the circuit information. This authentication processing is executed based on the functions of the transmission processing unit 1002A, the reception processing unit 1002B, and the authentication processing unit 1002C included in the device authentication unit 1002.

The transmission processing unit 1002A transmits a predetermined challenge value to the monitoring target device 22a to which the circuit information distribution unit 1001 has distributed the circuit information via the wide area communication network. The “challenge value” is an input value for obtaining a corresponding output value (response value) from the PUF circuit, and may be mainly a random number.
The reception processing unit 1002B receives the response value corresponding to the challenge value from the monitoring target device 22a that has transmitted the challenge value via the wide area communication network. The “response value” is an output value that the PUF circuit uniquely outputs in response to the challenge value when a predetermined challenge value is input to the PUF circuit formed in the monitored device 22a.
The authentication processing unit 1002C monitors based on the input/output correspondence information (also referred to as CRP (Challenge Response Pair)) of the PUF circuit formed in the monitored device 22a and the response value received from the monitored device 22a. The target device 22a is authenticated. “CRP” is information indicating a correspondence relationship between an input value (challenge value) and an output value (response value) of the PUF circuit, and is a challenge for each product (monitoring target device 22a) and each PUF circuit. It is an information table in which a plurality of pairs of values and response values are recorded. Since the response value output corresponding to the challenge value is determined depending on the physical individual difference such as the signal delay difference generated in the PUF circuit, even if the logical circuit configuration of the PUF circuit is the same, If the (monitoring target device 22a) is different, the same response value cannot be output for the same challenge value. Therefore, when the response value acquired in advance as the CRP is the same as the response value received via the wide area communication network, the authentication processing unit 1002C determines that the device to which the challenge value is transmitted is authentic. It is possible to determine that the target device is the monitoring target device 22a to be newly added to the embedded system 2.
The CRP of the PUF circuit of the monitoring target device 22a is measured in advance before the monitoring target device 22a is shipped and registered in the distributed ledger of the distributed ledger system configured by the monitoring system 1.

(Functional configuration of monitored device)
FIG. 4 is a diagram showing a functional configuration of the monitoring target device according to the first embodiment.
The configuration of the monitoring target device 22a illustrated in FIG. 4 is the same for other monitoring target devices (LS22, IO device 23, etc.) that configure the other embedded system 2.

As shown in FIG. 4, the monitored device 22a includes a CPU 220, a ROM 221, an FPGA 222, a RAM 223, a flash ROM 224, and a communication interface 225.

The CPU 220 is a processor that controls the entire operation of the monitoring target device 22a. The CPU 220 performs various functions described below by operating according to a program prepared in advance. Further, the CPU 220 officially operates as a component of the embedded system 2 that controls the gas turbine and the like by operating according to a predetermined control program after being authenticated by the monitoring device 10a.
The ROM 221 is a non-rewritable non-volatile memory. In the ROM 221 according to this embodiment, a common key SK for realizing the common key cryptosystem is recorded in advance. The common key SK is the same as that recorded in the ROM 101 of the monitoring device 10a. Further, although not shown in FIG. 4, the ROM 221 stores a boot program for performing authentication with the monitoring device 10a at the time of initial activation or the like.
The FPGA 222 is an integrated circuit capable of forming a desired logic circuit after manufacturing. In the FPGA 222, a PUF circuit C_PUF and an encryption key generation circuit C_ENC based on the circuit information received from the monitoring device 10a (circuit information distribution unit 1001) are formed. Note that, at the initial shipment of the monitored device 22a, the PUF circuit C_PUF and the encryption key generation circuit C_ENC are not formed in the FPGA 222.
The RAM 223 is a rewritable volatile memory. The RAM 223 is loaded with programs for the CPU 220 to perform various functions and operate.
The flash ROM 224 is a rewritable nonvolatile memory. The flash ROM 224 stores an encrypted control program (encrypted control program E_PRG) and a predetermined challenge value CH. Note that no information is recorded in the flash ROM 224 when the monitored device 22a is initially shipped.
The communication interface 225 is an interface for communicating with the monitoring device 10a or the like through a wide area communication network.

The CPU 100 operates in accordance with the boot program recorded in the ROM 221, thereby exerting the functions of the mutual authentication unit 2200, the circuit formation unit 2201, the device authentication request unit 2202, the encryption processing unit 2203, and the decryption processing unit 2204.

The mutual authentication unit 2200 performs mutual authentication processing with the monitoring device 10a at the time of initial activation. Mutual authentication processing is authentication through mutual common keys SK.
The circuit forming unit 2201 forms the PUF circuit C_PUF and the encryption key generation circuit C_ENC in the FPGA 222 based on the circuit information received from the monitoring device 10a. The encryption key generation circuit C_ENC may be a circuit based on a well-known common key encryption algorithm (for example, Advanced Encryption Standard; AES).
After the circuit forming unit 2201 forms the PUF circuit C_PUF in the FPGA 222, the device authentication requesting unit 2202 requests the monitoring device 10a to perform formal authentication using the PUF circuit C_PUF.
After the formal authentication by the monitoring device 10a is completed, the encryption processing unit 2203 encrypts the control program for officially operating as a component of the embedded system 2, and writes the encrypted control program E_PRG to the flash ROM 224 of its own device. To record.
The decryption processing unit 2204 decrypts the encrypted control program E_PRG recorded in the flash ROM 224 of its own device and expands it in the RAM 223. As a result, the CPU 100 officially operates as a component device of the embedded system 2.

(Processing flow of mutual authentication phase)
FIG. 5 is a diagram illustrating a processing flow of a mutual authentication phase performed between the monitoring device and the monitoring target device according to the first embodiment.
The process flow of the mutual authentication phase shown in FIG. 5 starts from the stage when the monitoring target device 22a connected to the network of the embedded system 2 is activated for the first time. As a premise, the monitored device 22a starts the mutual authentication phase shown in FIG. 5 by using the fact that the PUF circuit C_PUF and the encryption key generation circuit C_ENC are not installed (formed) in the FPGA 222 of its own device.

First, the activated monitoring target device 22a requests mutual authentication from the monitoring device 10a. Specifically, the mutual authentication unit 2200 of the monitored device 22a creates a mutual authentication random number that is a random number. Then, the mutual authentication unit 2200 transmits the mutual authentication request command and the mutual authentication random number to the predetermined connection destination address (monitoring device 10a) (step S00).
Upon receiving the mutual authentication request command and the mutual authentication random number from the outside (monitoring target device 22a), the mutual authentication receiving unit 1000 of the monitoring device 10a records the received mutual authentication random number in the ROM 101 of its own device. The common key SK is used for encryption (step S01). Then, the mutual authentication receiving unit 1000 returns the mutual authentication random number encrypted with the common key SK (encrypted mutual authentication random number) to the transmission source (monitoring target device 22a) (step S02).

The mutual authentication unit 2200 of the monitoring target device 22a decrypts the encrypted mutual authentication random number received from the monitoring device 10a with the common key SK recorded in the ROM 221 of the own device. Furthermore, the mutual authentication unit 2200 determines whether the random number for mutual authentication decrypted with the common key SK and the random number for mutual authentication created in step S00 match (step S03). As a result of the match determination, if the two match, the monitored device 22a determines that the genuine monitoring device 10a is the communication target, and proceeds to the circuit information distribution phase.

It should be noted that all exchanges of information between devices performed in the following phases (circuit information distribution phase (FIG. 6) and device authentication phase (FIG. 7)) are performed using the common key cryptosystem using the common key SK. Shall be performed.

As a result of the match determination, if the two do not match, the monitored device 22a determines that the genuine monitoring device 10a is not the communication target, and stops the subsequent processing.

(Processing flow of circuit information distribution phase)
FIG. 6 is a diagram illustrating a processing flow of a circuit information distribution phase performed between the monitoring device and the monitoring target device according to the first embodiment.
The process flow of the circuit information distribution phase shown in FIG. 6 starts from the stage where mutual authentication is performed through the mutual authentication phase (steps S00 to S03 in FIG. 5).

First, the monitored device 22a requests the monitoring device 10a to distribute the circuit information. Specifically, the circuit forming unit 2201 of the monitored device 22a transmits a circuit information request command to the monitoring device 10a (step S10). It is assumed that the circuit information request command includes a device ID (for example, a manufacturing number or the like) that can individually identify the product (monitoring target device 22a itself).

Upon receiving the circuit information request command from the monitoring target device 22a, the circuit information distribution unit 1001 of the monitoring device 10a issues a transaction completion approval request to the other monitoring device 10b included in the monitoring system 1 (step S11). Specifically, the circuit information distribution unit 1001 transmits the transaction completion approval request command and the circuit information request command from the monitored device 22a to all of the other monitoring devices 10b.

Upon receiving the transaction completion approval request command and the circuit information request command from the monitoring target device 22a from the monitoring device 10a, the other monitoring device 10b may distribute the circuit information in response to the circuit information request command. A consensus building process is performed to determine whether or not (step S12). Specifically, each of the other monitoring devices 10b has the device ID (identification information of the monitored device 22a) included in the circuit information request command in advance in the distributed ledger (recording medium 104) of the distributed ledger system. It is determined whether or not it is registered. Here, it is assumed that the device ID of the monitored device 22a added to the embedded system 2 is registered in advance in the distributed ledger (see FIGS. 8 and 9).
Further, each of the other monitoring devices 10b verifies whether the circuit information request command from the monitoring target device 22a has a tampering trace.
Note that a generally known consensus building algorithm (for example, Practical Byzantine Fault Tolerance; PBFT or the like) may be used for the consensus building process performed by the monitoring device 10a and the other monitoring device 10b in step S12.

If no problem is found in the content of the circuit information request command from the monitored device 22a as a result of the above determination and verification, the other monitoring device 10b performs monitoring based on the consensus that "the circuit information may be distributed". A transaction approval command is returned to the device 10a (step S13).

Upon receiving the transaction approval command from the other monitoring device 10b, the circuit information distribution unit 1001 of the monitoring device 10a sends the circuit information registered in advance in the distributed ledger (recording medium 104) to the monitored device 22a. It is distributed (step S14). The circuit information includes circuit information for forming the PUF circuit C_PUF in the FPGA 222 of the monitoring target device 22a and circuit information for forming the encryption key generating circuit C_ENC.

Upon receiving the circuit information from the monitoring device 10a, the circuit forming unit 2201 of the monitoring target device 22a verifies the validity of the circuit information. Specifically, the circuit forming unit 2201 transmits the hash value inquiry command of the circuit information received in step S14 to the monitoring device 10a and the other monitoring device 10b (step S15).

When the monitoring device 10a and the other monitoring device 10b receive the circuit information hash value inquiry command from the monitoring target device 22a, the monitoring device 10a and the other monitoring device 10b respectively refer to the recording medium 104 and distribute the circuit information hash value to the monitoring target device 22a. Is searched (step S16).
Here, it is assumed that the circuit information distributed in step S14 and the hash value of the circuit information are registered in advance in the distributed ledger (recording medium 104) of the distributed ledger system (see FIG. 10). ..

The monitoring device 10a and the other monitoring device 10b return the search result of the hash value of the circuit information recorded in each distributed ledger (recording medium 104) to the monitoring target device 22a (step S17).

When the hash value of the circuit information is received from the monitoring device 10a and the other monitoring device 10b, the circuit forming unit 2201 of the monitored device 22a verifies the circuit information received from the monitoring device 10a (step S18). Specifically, the circuit forming unit 2201 itself calculates the hash value of the circuit information received from the monitoring device 10a in step S14, and whether the calculation result matches the hash value received in step S17. To judge.

If the calculation result of the hash value of the circuit information received in step S14 matches the hash value received in step S17, it can be determined that the circuit information received in step S14 is authentic. In this case, the circuit forming unit 2201 forms (installs) the PUF circuit C_PUF and the encryption key generation circuit C_ENC in the FPGA 222 of the device itself based on the circuit information received in step S14 (step S19).
When the PUF circuit C_PUF and the encryption key generation circuit C_ENC are formed in the FPGA 222 of the own device, the monitored device 22a then proceeds to the device authentication phase using the formed PUF circuit C_PUF.

On the other hand, if the calculation result of the hash value of the circuit information received in step S14 does not match the hash value received in step S17, the circuit forming unit 2201 determines that it has not received the authentic circuit information. Therefore, the PUF circuit C_PUF and the encryption key generation circuit C_ENC are not formed in the FPGA 222 of the own device.

(Process flow of device authentication phase)
FIG. 7 is a diagram illustrating a processing flow of a device authentication phase performed between the monitoring device and the monitoring target device according to the first embodiment.
The processing flow of the device authentication phase shown in FIG. 7 is started from the stage where the PUF circuit C_PUF is formed in the FPGA 222 of the monitored device 22a through the circuit information distribution phase (steps S10 to S19 in FIG. 6).

First, the device authentication requesting unit 2202 of the monitored device 22a transmits a device authentication request command to the monitoring device 10a so as to be officially authenticated as a component of the embedded system 2 (step S20).

Upon receiving the device authentication request command from the monitored device 22a, the device authentication unit 1002 (transmission processing unit 1002A) of the monitoring device 10a sets the challenge value out of the CRP information registered in the distributed ledger (recording medium 104). One is selected (see FIGS. 8 and 9), and the selected challenge value is transmitted to all the monitoring target devices 22a and other monitoring devices 10b (step S21).

Upon receiving the challenge value from the monitoring device 10a, the device authentication requesting unit 2202 inputs the challenge value into the PUF circuit C_PUF of the FPGA 222. Then, the device authentication requesting unit 2202 acquires the output value output from the PUF circuit C_PUF corresponding to the input as the response value of the PUF circuit C_PUF (step S22).

The device authentication requesting unit 2202 transmits the response value acquired in step S22 to the monitoring device 10a (step S23). The device authentication unit 1002 (reception processing unit 1002B) of the monitoring device 10a receives the response value of the PUF circuit C_PUF from the monitoring target device 22a.

Next, the device authentication unit 1002 (authentication processing unit 1002C) of the monitoring device 10a searches the CRP information registered in the distributed ledger for a response value corresponding to the challenge value transmitted in step S21 (FIG. 8 and FIG. 9). Then, the device authentication unit 1002 determines whether the retrieved response value (response value recorded in the CRP) matches the response value received in step S23 (step S24).

As a result of the match determination in step S24, if the two match, the device authentication unit 1002 sends a transaction completion approval request to the other monitoring device 10b included in the monitoring system 1 (step S25). Specifically, the device authentication unit 1002 transmits the transaction approval request command and the response value from the monitored device 22a received in step S23 to all the other monitoring devices 10b.

When the other monitoring device 10b receives the transaction completion approval request command and the response value from the monitoring target device 22a from the monitoring device 10a, the monitoring target device 22a that has transmitted the response value configures the embedded system 2 as one configuration. A consensus building process is performed to determine whether the device can be officially authenticated (step S26). Specifically, each of the other monitoring devices 10b searches the CRP registered in the distributed ledger (recording medium 104) for a response value corresponding to the challenge value received in step S21. Then, the device authentication unit 1002 determines whether the retrieved response value (response value recorded in the CRP) matches the response value received in step S23.
Note that a generally known consensus building algorithm (for example, PBFT or the like) may be used for the consensus building process performed by the monitoring device 10a and the other monitoring device 10b in step S26.
In addition, the monitoring device 10a and the monitoring device 10b transmit information to the monitoring target device 22a in step S21, such as the challenge value (used challenge value), the result of the consensus forming process, and the date and time when the consensus forming process is performed. Is newly registered in the distributed ledger (step S26).

When the response value from the monitoring target device 22a matches the response value recorded in each CRP as a result of the above-mentioned matching determination, the other monitoring device 10b "formally states as a component device of the embedded system 2". Based on the consensus that "you may authenticate", a transaction approval command is returned to the monitoring device 10a (step S27).

When the transaction approval command is received from the other monitoring device 10b, the device authentication unit 1002 of the monitoring device 10a delivers the authentication command to the monitoring target device 22a in response to the device authentication request command of step S20 (step S28). When the authentication command is distributed from the monitoring device 10a, for example, the EMS 21 (FIG. 2) of the embedded system 2 triggers the reception of the authentication command from the monitoring device 10a as a trigger to notify the monitored device 22a of the embedded system 2. A control program for operating as one component (logic solver) is transmitted.
The encryption processing unit 2203 of the monitored device 22a encrypts the control program received from the EMS 21 and records it in the flash ROM 224 of the monitored device 22a (step S29). Details of the process of step S29 performed by the encryption processing unit 2203 will be described later.

(Data structure of the first distributed ledger)
FIG. 8 is a diagram showing a data structure of the first distributed ledger recorded in the monitoring device according to the first embodiment.
9 is a diagram showing a data structure of input/output correspondence information (CRP) recorded in the monitoring device according to the first embodiment.

FIG. 8 shows the data structure of the first distributed ledger recorded in the recording medium 104 of the monitoring device 10a.
As shown in FIG. 8, each block B1 forming the first distributed ledger has a block header B10 and CRP information B11.
The block header B10 has a hash value of all data (CRP information B11) included in each block B1 and a hash value of a previous block header (block header B10 of the previously registered block B1).
In the CRP information B11, the CRP obtained by the preliminary measurement is recorded for each product (monitored device 22a) and for each PUF circuit.

Here, the CRP information will be described in detail with reference to FIG.
As shown in FIG. 9, the CRP information is specified by a device ID that can identify the monitoring target device 22a, a PUF circuit ID that can identify the type (logical configuration) of the PUF circuit, and the device ID and the PUF circuit ID. The correspondence between the challenge value and the response value of the PUF circuit C_PUF is shown.
In this way, the challenge value and the response value are indicated by a value having a predetermined number of bits (for example, 128 bits). The CRP information is measured before each shipment of the monitored device 22a for each device and each type of PUF circuit, and registered in the distributed ledger.

In the process of step S21 of FIG. 7, the device authentication unit 1002 of the monitoring device 10a selects one challenge value from the CRP information shown in FIG. 9 and transmits it to the monitored device 22a.
Further, in the processing of step S24 of FIG. 7, the device authentication unit 1002 searches the CRP information shown in FIG. 9 for a response value corresponding to the challenge value transmitted in step S21. Then, the device authentication unit 1002 determines whether the retrieved response value (response value recorded in the CRP) matches the response value received in step S23.

(Data structure of the second distributed ledger)
FIG. 10 shows the data structure of the second distributed ledger recorded in the recording medium 104.
As shown in FIG. 10, each block B2 forming the second distributed ledger has a block header B20, circuit information and a hash value of the PUF circuit (hereinafter referred to as PUF circuit information group B21), and an encryption key. The circuit information of the generation circuit and the hash value (hereinafter referred to as the encryption key generation circuit information group B22) are included.
The block header B20 is a hash value of all data (PUF circuit information group B21 and encryption key generation circuit information group B22) included in each block B2 and a hash of the previous block header (the block header B20 of the previously registered block B2). With values and.

In the process of step S14 of FIG. 6, the circuit information distribution unit 1001 of the monitoring device 10a uses the second distributed ledger illustrated in FIG. 10 to input the circuit information of the PUF circuit information group B21 to be installed in the monitored device 22a and the encryption. The circuit information of the key generation circuit information group B22 is specified and transmitted to the monitoring target device 22a.
In addition, when the monitoring device 10a and the other monitoring device 10b receive the hash value inquiry command of the circuit information from the monitored device 22a in the process of step S16 of FIG. The retrieved hash value of each circuit information is retrieved.

(Processing flow after authentication)
11A and 11B are diagrams showing a processing flow of the monitoring target device according to the first embodiment, respectively.

First, with reference to FIG. 11A, a process (process of step S29 of FIG. 7) performed by the monitored device 22a immediately after being authenticated by the monitoring device 10a will be described.

As shown in FIG. 11A, the encryption processing unit 2203 of the monitoring target device 22a generates an arbitrary challenge value CH (random number) (step S30). The challenge value CH generated here may be an arbitrary random number regardless of the challenge value (the challenge value recorded in the CRP information) used in the device authentication phase (FIG. 7).
Next, the encryption processing unit 2203 inputs the challenge value CH generated in step S30 into the PUF circuit C_PUF of the FPGA 222 (step S31).
Next, the encryption processing unit 2203 acquires the response value output from the PUF circuit C_PUF as a result of step S31. Then, the encryption processing unit 2203 inputs the acquired response value to the encryption key generation circuit C_ENC of the FPGA 222 and generates an encryption key (step S32).
Next, the encryption processing unit 2203 encrypts the control program acquired in step S28 with the encryption key generated in step S32 (step S33).
Next, the encryption processing unit 2203 writes the control program E_PRG encrypted in step S33 into the flash ROM 224 (step S34).
At the same time, the encryption processing unit 2203 writes the challenge value CH generated in step S30 in the flash ROM 224 (step S35).

Next, with reference to FIG. 11B, a process at the time of starting the monitored device 22a for the second time and thereafter (normal starting process) will be described.

As a result of the processing illustrated in FIG. 11A, the monitored device 22a is in a state in which the encrypted control program E_PRG is written in the flash ROM 224. At the second and subsequent startups, the monitored device 22a decrypts the encrypted control program E_PRG and operates as a component device of the embedded system 2.

Specifically, the decryption processing unit 2204 of the monitored device 22a reads and acquires the challenge value CH recorded in the flash ROM 224 (step S40).
Next, the decoding processing unit 2204 inputs the challenge value CH acquired in step S40 into the PUF circuit C_PUF of the FPGA 222 (step S41).
Next, the decoding processing unit 2204 acquires the response value output from the PUF circuit C_PUF as a result of step S41. Then, the decryption processing unit 2204 inputs the acquired response value to the encryption key generation circuit C_ENC of the FPGA 222 to generate an encryption key (step S42).
Next, the decryption processing unit 2204 decrypts the encrypted control program E_PRG recorded in the flash ROM 224 with the encryption key generated in step S42 (step S43).
Next, the decryption processing unit 2204 expands the control program decrypted in step S43 in the RAM 223 (step S44).
As a result, the CPU 220 of the monitored device 22a operates according to the control program loaded in the RAM 223.

(Action, effect)
As described above, the monitoring device 10a according to the first embodiment is one of the plurality of nodes configuring the distributed ledger system, and the information processing device configuring the embedded system 2 (for example, a logic solver, an IO device). Etc.) are monitored as the monitoring target device 22a.
The monitoring device 10a provides the circuit information distribution unit 1001 (see step S14 in FIG. 6) that distributes the circuit information for forming the PUF circuit C_PUF to the monitoring target device 22a, and the monitoring target device 22a that distributes the circuit information. A transmission processing unit 1002A that transmits a predetermined challenge value (see step S21 in FIG. 7) and a reception processing unit 1002B that receives the response value of the PUF circuit C_PUF formed in the monitored device 22a (step S23 in FIG. 7). (See FIG. 7), the input/output correspondence information (CRP) of the PUF circuit C_PUF formed in the monitoring target device 22a, and the received response value based on the authentication processing unit 1002C (FIG. 7). (See step S24).
Further, the CRP and circuit information described above are registered in advance in the distributed ledger system configured by the monitoring system 1.

Further, as described above, the monitored device 22a (information processing device) according to the first embodiment requests circuit information from the monitoring device 10a when the PUF circuit C_PUF is not formed in the device itself (see FIG. 6), the circuit forming unit 2201 that forms the PUF circuit C_PUF based on the circuit information received from the monitoring device 10a and the PUF circuit C_PUF are formed. A device authentication request unit 2202 for making an authentication request (see step S20 in FIG. 7). Then, the device authentication requesting unit 2202 inputs the challenge value received from the monitoring device as a response to the authentication request into the PUF circuit (see step S23 in FIG. 7), and returns the response value as the output result to the monitoring device 10a. (See step S24 in FIG. 7).

According to the above configuration, the monitoring target device 22a is authenticated based on the CRP preregistered in the distributed ledger system configured by the monitoring system 1 (see steps S20 to S28 in FIG. 7). As a result, the tamper resistance of the CRP is strengthened, so that the reliability of the validity verification of the product using the PUF can be increased.
Further, according to the above configuration, before the device authentication phase, the process of forming the PUF circuit is performed on the monitored device 22a based on the circuit information distributed from the outside (see steps S10 to S19 in FIG. 6). ). As a result, the monitored device 22a is shipped in a state in which the PUF circuit C_PUF is not formed, so it is possible to suppress the information leakage of the PUF circuit C_PUF.

Further, the monitoring device 10a (authentication processing unit 1002C) according to the first embodiment further authenticates the device to be monitored based on the result of the consensus building process by the plurality of other nodes configuring the distributed ledger system. Perform (see steps S25 to S27 in FIG. 7).
By doing so, the success or failure of the authentication based on the CRP is performed at each of the plurality of nodes, so that the reliability of the success or failure of the authentication can be enhanced.

Further, the monitoring device 10a (circuit information distribution unit 1001) according to the first embodiment receives the inquiry about the hash value of the circuit information distributed by the monitoring device 10a from the monitoring target device 22a, and then the distributed ledger system. The hash value of the circuit information registered in advance is transmitted. By doing so, the monitored device 22a can verify the validity of the received circuit information based on the hash values transmitted from all the nodes (monitoring device 10). That is, the monitored device 22a can obtain confirmation that the distributed circuit information is authentic (recorded in the distributed ledger system).

(Modification of the first embodiment)
Although the monitoring system 1 and the monitoring device 10 according to the first embodiment have been described in detail above, the specific aspects of the monitoring system 1 and the monitoring device 10 are not limited to those described above, and the gist thereof will be described. It is possible to add various design changes and the like without departing from the scope.

For example, the monitoring device 10a and the other monitoring device 10b according to the first embodiment transmitted to the monitoring target device 22a in step S26 of FIG. 7 together with the consensus process of authenticating the monitoring target device 22a. The challenge value (used challenge value) and the like have been described as being newly registered in the distributed ledger (recording medium 104).
Here, in the case where the monitoring device 10a further performs the device authentication process for the monitored device 22a again, in step S21 of FIG. 7, the distributed ledger is referred to, and the challenge value not registered as the used challenge value is used. (That is, only the challenge value that has never been transmitted to the monitoring device 22a) may be selected and transmitted.
By doing so, the challenge value transmitted by the monitoring device 10a to the monitored device 22a in the device authentication phase is always transmitted for the first time, and thus the challenge value is eavesdropped and recognized by a third party. The risk can be reduced.

The circuit information distribution unit 1001 according to the first embodiment has been described as a circuit that distributes the circuit information for forming the encryption key generation circuit C_ENC together with the circuit information for forming the PUF circuit C_PUF (step of FIG. 6). (See S14). Further, the encryption processing unit 2203 is described as inputting the response value of the PUF circuit C_PUF to the encryption key generation circuit C_ENC to generate an encryption key and encrypting the control program using the encryption key (FIG. 11A, steps S32 to S33). However, the other embodiments are not limited to the above aspect.
That is, the circuit information distribution unit 1001 according to another embodiment distributes only the circuit information for forming the PUF circuit C_PUF, and the encryption processing unit 2203 of the monitoring target device 22a controls the PUF circuit C_PUF. The control program may be directly encrypted using the response value. In this case, the decryption processing unit 2204 of the monitoring target device 22a directly decrypts the encrypted control program E_PRG using the response value of the PUF circuit C_PUF.

Further, the monitoring system 1 and each monitoring device 10 according to the first embodiment have been described as a mode in which they are installed outside the embedded system 2 (see FIGS. 1 and 2). However, other embodiments are not limited to this aspect.
That is, each function (FIG. 3) included in the monitoring device 10a may be incorporated in the OPS 20, EMS 21, etc. installed as a component of the embedded system 2.
Moreover, the monitoring device 10 may be in a mode in which a plurality of monitoring devices 10 are virtually installed in one hardware (housing).

<Second Embodiment>
Next, a monitoring system and monitored devices according to the second embodiment will be described with reference to FIG.

(Processing flow of monitored device)
FIG. 12 is a diagram illustrating a processing flow of the monitoring target device according to the second embodiment.
With reference to FIG. 12, a process at the time of second and subsequent startup of the monitored device 22a according to the second embodiment (normal startup process) will be described.

The monitored device 22a according to the second embodiment executes the device authentication phase again at the second and subsequent startups. That is, the monitoring target device 22a again makes a device authentication request (step S20 in FIG. 7) to the monitoring device 10a at the second and subsequent startups. Then, after undergoing the authentication process (steps S21 to S27) by the monitoring device 10a and the like, the authentication is newly received from the monitoring device 10a (step S28 in FIG. 7).
The monitoring target device 22a determines whether or not the device has been normally authenticated by the monitoring device 10a in the device authentication phase (steps S20 to S28) (step S50).
When normally authenticated in the device authentication phase (steps S20 to S28) (step S50: YES), the monitored device 22a executes the control start process (steps S40 to S44 in FIG. 11B) and follows the control program. Take action.
On the other hand, when the device is not normally authenticated in the device authentication phase (steps S20 to S28) (step S50: NO), the monitored device 22a performs the process without executing the control start process (steps S40 to S44 in FIG. 11B). To finish.

(Action, effect)
As described above, in the monitored device 22a according to the second embodiment, when the encrypted control program E_PRG is recorded in the flash ROM 224 and then is activated again, the device authentication phase (step of FIG. 7). After executing S20 to S28) again to obtain the authentication, the encrypted control program E_PRG is decrypted and executed (steps S40 to S44 in FIG. 11B).
That is, according to the monitoring target device 22a according to the second embodiment, when the decryption processing unit 2204 receives the authentication from the monitoring device 10a as a result of the authentication request (step S20 in FIG. 7) (step S50: YES). Then, the previously encrypted control program E_PRG is decrypted.

Here, according to the monitored system 22a of the first embodiment, when the monitored system 22a itself is stolen, the control program is decrypted and executed only by activating the monitored system 22a at the theft destination. Up to (steps S40 to S44 in FIG. 11B) are automatically performed. Then, the control program decrypted by a third party may be investigated and the know-how may be leaked.
However, according to the monitored device 22a according to the second embodiment, when the monitored device 22a is activated in a stand-alone manner at the theft destination, authentication by the monitoring device 10a cannot be obtained (step S50: NO). The program is not decrypted and executed (steps S40 to S44 in FIG. 11B). Therefore, even if the monitored device 22a itself is stolen, the know-how of the control program can be prevented from leaking.

<Third Embodiment>
Next, a monitoring system and a monitoring target device according to the third embodiment will be described with reference to FIG.

(Processing flow of monitored device)
FIG. 13 is a diagram illustrating a processing flow of the monitoring target device according to the third embodiment.
With reference to FIG. 13, a description will be given of a process at the time of second and subsequent activation of the monitored device 22a according to the third embodiment (normal activation process).

The monitored device 22a according to the third embodiment executes the device authentication phase again at the second and subsequent startups. That is, the monitoring target device 22a again makes a device authentication request (step S20 in FIG. 7) to the monitoring device 10a at the second and subsequent startups. Then, after undergoing the authentication process (steps S21 to S27) by the monitoring device 10a and the like, the authentication is newly received from the monitoring device 10a (step S28 in FIG. 7).
In the device authentication phase (steps S20 to S28), the monitoring target device 22a determines whether or not the device has been normally authenticated by the monitoring device 10a (step S60).
When normally authenticated in the device authentication phase (steps S20 to S28) (step S60: YES), the monitored device 22a executes the control start process (steps S40 to S44 in FIG. 11B) and follows the control program. Take action.
On the other hand, when the device is not normally authenticated in the device authentication phase (steps S20 to S28) (step S60: NO), the monitored device 22a stores the information (encrypted control program E_PRG) previously recorded in the flash ROM 224. , Challenge value CH) and all the circuits (PUF circuit C_PUF, encryption key generation circuit C_ENC) formed in the FPGA 222 are erased (step S61).

(Action, effect)
As described above, according to the monitoring target device 22a according to the third embodiment, when the device authentication requesting unit 2202 does not receive authentication from the monitoring device 10a as a result of the authentication request (step S20 in FIG. 7), The encrypted control program E_PRG and the like are deleted.

According to such an aspect, when the monitored device 22a is activated standalone in the theft destination, not only is the decryption and execution of the control program (steps S40 to S44 in FIG. 11B) not performed, but the flash ROM 224 is also stored. All the recorded information and the circuits formed in the FPGA 222 are erased. As a result, if the monitored device 22a itself is stolen, it is possible to more reliably suppress the information leakage.

<Fourth Embodiment>
Next, a monitoring system and monitored devices according to the fourth embodiment will be described with reference to FIG.

(Data structure of input/output correspondence information)
FIG. 14 is a diagram showing a data structure of the input/output correspondence information recorded in the monitoring device according to the fourth embodiment.
Unlike the first embodiment (FIG. 9), the CRP information recorded in the monitoring device according to the fourth embodiment has two types of PUF circuits (device ID: X1) for two monitored PUF circuits (device ID: X1). A pair of challenge value and response value for each PUF circuit ID: α1, α2) is recorded.

In the present embodiment, for example, the producer (manufacturer) of the monitored device 22a first installs the PUF circuit C_PUF identified by the PUF circuit ID: α1 before shipping the monitored device 22a (device ID: X1). Then, the pair of challenge value and response value of the PUF circuit C_PUF (PUF circuit ID: α1) is measured. Next, the PUF circuit C_PUF identified by the PUF circuit ID: α2 is installed, and the pair of challenge value and response value of the PUF circuit C_PUF (PUF circuit ID: α2) is measured.
Then, the producer of the monitored device 22a registers the CRP information as shown in FIG. 14 in the distributed ledger.

(Action, effect)
With the above-described aspect, when all the challenge values of the PUF circuit C_PUF (PUF circuit ID: α1) formed in the monitored device 22a (device ID: X1) have been used, By installing another PUF circuit C_PUF (PUF circuit ID: α2), the monitored device 22a (device ID: X1) can be continuously used.
In this case, the monitored device 22a makes a circuit information request (step S10 in FIG. 6) for requesting circuit information about the new PUF circuit C_PUF (PUF circuit ID: α2) immediately before the challenge value is exhausted. May be.

In another embodiment, the producer of the monitored device 22a may temporarily collect the monitored device 22a immediately before the challenge value of the PUF circuit C_PUF (PUF circuit ID: α1) is exhausted. Then, the producer of the monitored device 22a installs a new PUF circuit C_PUF identified by the PUF circuit ID: α2 for the collected monitored device 22a, and challenges the PUF circuit C_PUF (PUF circuit ID: α2). A value/response value pair may be registered in the distributed ledger.

<Fifth Embodiment>
Next, a monitoring system and a monitoring target device according to the fifth embodiment will be described with reference to FIGS. 15 to 16.

(Functional configuration of monitoring device)
FIG. 15 is a diagram showing the functional configuration of the monitoring device according to the fifth embodiment.
As shown in FIG. 15, the CPU 100 of the monitoring device 10a according to the fifth embodiment exerts a function as an input/output correspondence information registration unit 1003 in addition to the functions of the first to fourth embodiments. In the new CRP registration phase, which will be described later, the input/output correspondence information registration unit 1003 first generates a plurality of types of challenge values (random numbers) and transmits them to the monitoring target device 22a. Next, the input/output correspondence information registration unit 1003 receives the response value corresponding to each challenge value from the monitoring target device 22a. Then, the input/output correspondence information registration unit 1003 creates input/output correspondence information of the PUF circuit C_PUF formed in the monitoring target device 22a and registers it in the distributed ledger system configured by the monitoring system 1.
Hereinafter, the processing flow performed by the input/output correspondence information registration unit 1003 in the new CRP registration phase will be described in detail.

(Processing flow of new CRP registration phase)
FIG. 16 is a diagram illustrating a processing flow of a new CRP registration phase performed between the monitoring device and the monitoring target device according to the fifth embodiment.
The process flow of the new CRP registration phase illustrated in FIG. 16 is executed, for example, when the challenge value is exhausted for one PUF circuit C_PUF (for example, PUF circuit ID: α1) formed in the monitored device 22a.

When the challenge value is exhausted for one PUF circuit C_PUF (PUF circuit ID: α1), the circuit distribution phase (steps S10 to S19 in FIG. 6) is executed, and a new PUF circuit C_PUF (for example, PUF circuit ID: α2). Is installed in the monitored device 22a.
Here, it is assumed that the CRP information about the PUF circuit C_PUF (PUF circuit ID: α2) newly installed in the monitoring target device 22a is not registered in advance in the distributed ledger before shipment.

In this case, the input/output correspondence information registration unit 1003 of the monitoring device 10a first generates a plurality of types of challenge values (random numbers) and transmits them to the monitoring target device 22a (step S70).
Next, the monitored device 22a inputs the generated challenge values of a plurality of types into the newly installed PUF circuit C_PUF (PUF circuit ID: α2) and acquires the response value (step S71).
Next, the monitored device 22a returns a plurality of types of response values corresponding to the plurality of types of challenge values to the monitoring device 10a (step S72).

The monitoring device 10a, based on the plurality of challenge values transmitted in step S70 and the plurality of response values received from the monitored device 22a in step S72, includes CRP information (a pair of challenge values and response values) ( That is, the CRP information about the newly installed PUF circuit C_PUF (PUF circuit ID: α2) is created and the CRP information is registered in the distributed ledger (step S73).

(Action, effect)
With the above-described aspect, the CRP information about the newly installed PUF circuit C_PUF can be created remotely even after the monitored device 22a is installed in the embedded system 2. Therefore, for example, as in the fourth embodiment, it is possible to save the time and effort for creating CRP information about a plurality of types of PUF circuits C_PUF in advance before shipment.

In each of the above-described embodiments, the processes of various processes of the above-described monitoring device 10 are stored in a computer-readable recording medium in the form of a program, and the computer reads and executes the program to execute Various processes are performed. The computer-readable recording medium refers to a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Further, the computer program may be distributed to the computer via a communication line, and the computer that receives the distribution may execute the program.

The above-mentioned program may be for realizing a part of the above-mentioned function. Further, it may be a so-called difference file (difference program) that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

Further, in another embodiment, a mode in which another computer connected via a network includes some of the functions of the monitoring device 10 described in the first to fifth embodiments (and their modifications) May be

Although some embodiments according to the present invention have been described above, all of these embodiments are presented as examples, and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the invention described in the claims and the equivalents thereof as well as included in the scope and the gist of the invention.

1 Monitoring System 10 Monitoring Device 100 CPU
1000 Mutual authentication acceptance unit 1001 Circuit information distribution unit 1002 Device authentication unit 1002A Transmission processing unit 1002B Reception processing unit 1002C Authentication processing unit 101 ROM
102 RAM
103 Communication Interface 104 Recording Medium 2 Embedded System 20 OPS
21 EMS
22 logic solver 23 IO device 22a logic solver (monitored device)
220 CPU
2200 Mutual authentication unit 2201 Circuit formation unit 2202 Device authentication request unit 2203 Encryption processing unit 2204 Decryption processing unit 221 ROM
222 FPGA
223 RAM
224 Flash ROM
225 Communication interface SK Common key C_PUF PUF circuit C_ENC Encryption key generation circuit E_PRG Encrypted control program CH Challenge value

Claims (5)

When the PUF circuit is not formed, a circuit forming unit that requests circuit information to the monitoring device and forms the PUF circuit based on the circuit information received from the monitoring device,
A device authentication requesting unit that requests authentication to the monitoring device when the PUF circuit is formed;
Equipped with
The device authentication request unit,
An information processing apparatus that inputs a challenge value received from the monitoring apparatus as a response to the authentication request to the PUF circuit and returns a response value that is an output result thereof to the monitoring apparatus. The information processing apparatus according to claim 1, further comprising a decryption processing unit that decrypts a control program that has been encrypted in advance when the authentication request is received from the monitoring apparatus as a result of the authentication request. The device authentication request unit,
The information processing apparatus according to claim 2, wherein the control program is erased when the authentication request does not result in authentication from the monitoring apparatus. When the PUF circuit is not formed, the circuit forming unit requests the monitoring device for the circuit information and forms the PUF circuit based on the circuit information received from the monitoring device.
When the PUF circuit is formed, a device authentication requesting unit makes an authentication request to the monitoring device,
Have
In the step of making the authentication request, the challenge value received from the monitoring device as a response to the authentication request is input to the PUF circuit, and a response value that is the output result is returned to the monitoring device. In the computer of the information processing device,
Requesting circuit information to the monitoring device when the PUF circuit is not formed, and forming the PUF circuit based on the circuit information received from the monitoring device;
Making an authentication request to the monitoring device when the PUF circuit is formed;
Run
A program for inputting the challenge value received from the monitoring device as a response to the authentication request to the PUF circuit and returning a response value as an output result to the monitoring device in the step of making the authentication request.

Images