JP2011217037A - Network system and theft preventing method - Google Patents

Abstract

The present invention provides a network system that can prevent reuse of an electronic device that has been illegally removed from a network and is less likely to cause false detection of unauthorized removal.
An electronic device having a unique public key used in a public key cryptosystem and its signature is stored in the electronic device, and the electronic device that does not hold the wearer secret information holds the wearer secret information at the time of activation. The mutual authentication partner electronic device exchanges the public key and its signature with each other, so that the required operation can be continued. The electronic device that holds the wearer's confidential information will continue the required operation on the condition that the mutual authentication using the public key is performed with another electronic device of the mutual authentication partner at the time of activation, and the other party's validity is confirmed. Made possible. When removing an electronic device from the network, make sure that the removal operator is valid, then clear the wearer's confidential information and the public key of the other electronic device for mutual authentication from the electronic device to be removed. , Removal is justified.
[Selection] Figure 1

Description

  The present invention relates to a security technique for suppressing theft of electronic equipment in a network system in which the electronic equipment is connected to a network, for example, a technique effective when applied to theft prevention of in-vehicle equipment mounted on an automobile.

  In Patent Document 1, when a device is mounted, the master and user of the in-vehicle bus are connected by a dedicated authentication device, and only the master via the dedicated authentication device can be removed, and the device does not operate if it is removed by any other method. The technology to do is described.

  In Patent Documents 2 and 3, the vibration applied to the device, the physical distance between the device and the user, the average moving speed of the vehicle, the moving route of the vehicle, etc. are analyzed so that the device does not operate if it is detected that it has been removed illegally Techniques to do are described.

  The techniques described in any of the above documents attempt to prevent the in-vehicle device from being stolen by preventing the in-vehicle device from operating when it is illegally removed from the vehicle.

JP 2002-144970 A JP 2009-54091 A Japanese Patent Laid-Open No. 2003-250181

  However, in the technique described in Patent Document 1, it is highly possible that the unauthorized removal prevention function of the device is invalidated by a fake master, and the device can be operated even after unauthorized removal.

  In the techniques of Patent Documents 2 and 3, since the unauthorized removal detection method is difficult, there is a possibility that the device will erroneously detect unauthorized removal and become inoperable.

  An object of the present invention is to provide a network system that can strongly prevent reuse of an electronic device that has been illegally removed from a network and that is less likely to cause erroneous detection of unauthorized removal.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  The following is a brief description of an outline of typical inventions disclosed in the present application.

  In response to the fact that multiple electronic devices connected to the network exchange authentication information with each other, the electronic devices communicate with each other at a predetermined timing, and a difference from the previous authentication communication is recognized. To detect the unauthorized removal or installation of electronic equipment.

  Furthermore, each electronic device has a nonvolatile memory that cannot be illegally read and falsified in each electronic device, and the private key distributed from a trusted organization, the public key with signature, and the public key of the trusted organization are stored in the nonvolatile memory. Hold. The electronic device that does not hold the information for authenticating the wearer receives the information for authenticating the wearer at the time of start-up and holds it in the nonvolatile memory, and the other electronic device connected to the network and the public key with signature After verifying the validity of the signature with a public key of a trusted organization, these are stored in the nonvolatile memory. An electronic device that holds information for authenticating the wearer is mutually authenticated by using a public key already exchanged with another electronic device connected to the network at the time of start-up. Necessary operations are made possible on the condition that it is confirmed that there is no change in the configuration. When removing the electronic device from the network, check the information for the wearer authentication stored in the non-volatile memory against the information given to the electronic device by the removal requester, and confirm that the removal requester is valid. The wearer authentication information and the public key of the other electronic device are erased from the nonvolatile memory so that the electronic device can be removed.

  When an unauthorized removal requester removes an electronic device and tries to connect to another network, the wearer authentication information and the public key of the electronic device connected to the network before removal remain in the nonvolatile memory of the electronic device. Therefore, it will try to mutually authenticate with the electronic device connected to the network before removal on the newly connected network. Naturally, since mutual authentication on the newly connected network fails, the electronic device does not operate correctly. That is, an electronic device that has been unjustly removed due to theft or the like does not operate, and the theft of the electronic device can be suppressed.

  The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.

  That is, according to the network system according to the present invention, it is difficult to cause erroneous detection of unauthorized removal, and it is possible to firmly prevent reuse of electronic devices that have been illegally removed from the network.

FIG. 1 is a flowchart illustrating an overall operation sequence from power-on to power-off of an electronic device in the network system according to the first embodiment. FIG. 2 is a block diagram illustrating a schematic configuration of the network system according to the first embodiment. FIG. 3 is a block diagram illustrating a configuration for performing wearer authentication, authentication of another electronic device, message authentication with another electronic device, and the like in the configuration of the electronic device X. FIG. 4 is a flowchart showing a specific example of public key registration processing. FIG. 5 is a flowchart showing a specific example of the wearer registration process. FIG. 6 is a flowchart illustrating an authentication operation performed by electronic devices to share a shared key. FIG. 7 is a flowchart illustrating the overall operation procedure of the removal process. FIG. 8 is a flowchart illustrating a processing procedure for issuing an erasure request after performing a process of sharing a shared key by a simplified process between an electronic device to be removed and another electronic device. FIG. 9 is a flowchart showing an example of the public key deletion cancellation process. FIG. 10 is a block diagram illustrating the configuration of a network system according to the second embodiment applied to a hierarchical network system. FIG. 11 is a block diagram illustrating the configuration of an electronic device used in the hierarchical network of FIG. FIG. 12 is a block diagram illustrating a network system according to the third embodiment for generating an in-vehicle device list. FIG. 13 is a block diagram illustrating a schematic configuration of a network system according to the fourth embodiment for creating a signed public key in the system. FIG. 14 is a block diagram showing an operation procedure in which a control device on the network for an electronic device mounted on the network generates a signed public key. FIG. 15 is a block diagram showing an operation procedure for exchanging the public key generated in FIG. 14 between electronic devices. FIG. 16 is a block diagram showing an operation procedure for obtaining the removal permission to be obtained when the electronic device is removed from the network.

1. First, an outline of a typical embodiment of the invention disclosed in the present application will be described. Reference numerals in the drawings referred to in parentheses in the outline description of the representative embodiments merely exemplify what are included in the concept of the components to which the reference numerals are attached.

[1] <Mounting authentication, mutual authentication, and removal authentication using the certificate authority's signature>
A network system (FIGS. 2 and 11) according to a typical embodiment of the present invention includes electronic devices (1 to 3, X, 1A to 3A, XA) connected to a network. The electronic device holds a private key (22) and a public key (21) unique to the electronic device, a signature (23) of the public key by a certificate authority, and a public key (24) of the certificate authority. A storage unit (20) including a volatile storage device and a rewritable nonvolatile storage device is included. The public key and the signature of the public key are exchanged and input with another electronic device that is subject to mutual authentication, and the public key is confirmed by itself on condition that the validity of the input public key is confirmed. After performing the authentication communication (300) stored in the non-volatile storage device, the required operation can be continued. In the case of such authentication communication, if the electronic device does not hold information for authenticating the wearer, prior to the authentication communication, information for authenticating the wearer is input and stored in its own nonvolatile storage device. Store (200, FIG. 5). If the electronic device does not have an information input device for authenticating the wearer, after completing mutual authentication with the other electronic device having such an input device, the other electronic device having the input device The wearer authentication information is input and transferred to the electronic device via the network. The another electronic device that has exchanged the public key and its signature and inputs the public key is stored in its nonvolatile storage device on condition that the validity of the input public key is confirmed. The electronic device holding the information for authenticating the wearer is mutually authenticated using the public key of the other electronic device held mutually with another electronic device that is subject to mutual authentication at the time of activation. The required operation can be continued on the condition that the validity of the electronic device of the other party is confirmed. (Figure 4)
From the above, the wearer trying to connect the electronic device to the network and the electronic device are linked by the information for authenticating the wearer. Further, each electronic device newly connected to the network exchanges a public key with an electronic device already connected to the network, thereby connecting each electronic device on the network. It is possible to verify the validity of the public key based on the signature of the public key.

  When the electronic device is removed from the network (FIG. 7), the electronic device instructed to be removed from the network uses the information for authenticating the wearer and confirms that the removal operator is valid. When the electronic device is attached to the network, authentication communication for deleting the public key exchanged with another electronic device is performed (FIG. 8), and the removal is justified. On the other hand, if the removal operator fails to confirm the validity, authentication communication for deleting the public key exchanged with other electronic devices connected to the network is not performed, and the electronic device and other The public key of the counterpart electronic device remains in both of the electronic devices.

  When another electronic device connected to the network is to be removed, the other electronic device to be removed according to the authentication communication for deleting the public key from the other electronic device to be removed. The public key exchanged with is deleted.

  Confirm that there is no change in the electronic device connected to the network by performing mutual authentication communication between the electronic device and the other electronic device using a public key held by each electronic device at a predetermined timing. can do. If the result of mutual authentication using all of the public keys held by the electronic device is not valid, the configuration of the network to which the electronic device is connected has changed from that planned by the electronic device. Therefore, it is assumed that the electronic device has been illegally removed. When unauthorized removal of an electronic device is detected, the electronic device will not operate.

  In this way, when an unauthorized person removes an electronic device from the network, the removal from the network is not performed correctly, so the electronic device has a public key of another electronic device in the removed network environment. It will remain as it is, and when the electronic device is connected to another network and started up, mutual authentication becomes abnormal and normal operation will not be performed. Therefore, the stolen electronic device does not operate correctly, and theft of the electronic device can be suppressed.

  Since mutual authentication of electronic devices is performed using a legitimate public key, the unauthorized removal prevention function is not invalidated by mutual authentication with fake devices.

  Since it is possible to easily detect unauthorized removal by mutual authentication using a public key, it does not happen that unauthorized removal is detected by mistake and becomes inoperable.

[2] <Public key deletion instruction of device to be removed>
In the network system according to Item 1, when the electronic device erases the public key of the mutual authentication partner and the wearer secret information stored in its nonvolatile storage device, the electronic device makes its public disclosure to the electronic device of the mutual authentication partner. A command for instructing key deletion is issued (FIG. 8).

  As a result, when the electronic device removal process is performed, it is possible to easily instruct the matching of the public keys that mutually connect the electronic devices remaining under the network permission.

[3] <Delete public key of device to be removed>
In the network system according to Item 2, in response to the delete command, the electronic device deletes the public key of the command requesting electronic device from its nonvolatile storage device (FIG. 8).

  Thereby, it is possible to easily realize the matching of the public key.

[4] <Mutual authentication>
In the network system according to any one of Items 1 to 3, in the mutual authentication, the electronic device exchanges information encrypted with the public key of the other party with the electronic device that is the target of mutual authentication. The predetermined information obtained as a shared key is acquired, information obtained by encrypting the predetermined information using the acquired shared key is sent to the partner electronic device, and the encrypted information returned from the partner electronic device is This is a process for validating the authentication result when the information obtained by decrypting using the shared key matches the predetermined information (FIG. 6).

  Thereby, messages using the shared key can be exchanged between electronic devices that have performed mutual authentication.

[5] <Tampering suppression of non-volatile storage device>
In the network system according to any one of Items 1 to 4, when the non-volatile storage device holds the secret information, the electronic device mutually interacts with all electronic devices that are subject to mutual authentication. The nonvolatile storage device is prohibited from being rewritten until a valid authentication result is obtained by the authentication.

  It becomes difficult to tamper with the public key held in the nonvolatile storage device of the electronic device that has been illegally removed.

[6] <Electronic devices in parallel>
In the network system according to any one of Items 1 to 5, with respect to the electronic devices connected to the network, one electronic device mutually targets all other electronic devices (FIG. 2).

  It is suitable for a small network configuration.

[7] <Electronic equipment related to hierarchy>
In the network system according to any one of Items 1 to 5, the electronic device includes an upper electronic device and a lower electronic device corresponding to the electronic device, and the lower electronic device sets the upper electronic device as a mutual authentication target (see FIG. 10).

  Since the lower electronic device can limit the upper electronic device to a mutual authentication target, it is suitable for a large-scale network configuration. Furthermore, since the mutual authentication target is limited, the storage capacity of the nonvolatile storage device that stores the public key and the like can be reduced.

[8] <Public key list>
In the network system according to Item 7, the upper electronic device creates a public key list of lower electronic devices connected to the network at a predetermined timing, and sets the public key list created this time and the public key list created last time. A change in the device connected to the network is detected by comparison, and the result is supplied to the communication device to the external network (FIG. 12).

  The communication device can search for an electronic device that has been illegally removed by transmitting change information of the connected device to a tracking organization of the theft device via an external network. This is particularly suitable for a system that uses a public key issued by a certificate authority.

[9] <Use of certificate authority>
In the network system according to any one of Items 1 to 8, the electronic device is an in-vehicle device, and a secret key unique to the electronic device, a public key, a signature of the public key by a certificate authority, and a public key of the certificate authority are each The information issued from the certificate authority and the information for authenticating the wearer is confidential information held by the wearer of the electronic device.

[10] <Mounting authentication, mutual authentication, detachment authentication using private signature>
The network system (FIG. 13) according to another embodiment of the present invention includes a control device (2B) that controls connection and removal of the electronic device (1B, XB) to the network and the electronic device. In the network systems according to items 1 to 9, the electronic system having an inappropriate public key is prevented from being connected to the network by using the signature of the public key authenticated by the certificate authority. In a network system, any one electronic device (control device) connected to the network generates a signature of a public key possessed by another electronic device, and enables valid authentication only within the network system (I (Referred to as a signature).

  The electronic device has a rewritable nonvolatile storage device (20_1B, 20_XB). The control device includes a non-volatile storage device (20_2B) that holds a specific secret key and a specific public key used for generating a signature to be given to an electronic device connected to a network. When the control device inputs information for authenticating a wearer not held in its own nonvolatile storage device, the control device stores the information in its own nonvolatile storage device and authenticates the wearer. And generating a public key and a private key of the corresponding electronic device based on the information of the electronic device, generating a signature of the public key using the specific private key, and generating the generated public key, the public key signature, and the specific public key The information for authenticating the wearer is given to the electronic device (FIG. 13). The electronic device to which the public key and the public key signature and the specific public key are newly given from the control device, the public key obtained by decrypting the public key signature with the specific public key, and the public key signature Is stored in its own non-volatile storage device (FIG. 14), and the public key and the signature of the public key are exchanged and input with another electronic device to be mutually authenticated (FIG. 15). On the condition that the validity of the input public key is confirmed, the public key is stored in its own nonvolatile storage device so that the required operation can be continued. The other electronic device that has been exchanged for the public key and its signature stores the public key in its non-volatile storage device on condition that the validity of the public key input from the other party is confirmed. The electronic device holding its own public key and the public key signature given from the control device is another electronic device that is mutually owned with another electronic device that is subject to mutual authentication at startup. The required operation can be continued on condition that mutual authentication using the public key is performed to confirm the validity of the partner electronic device.

  When the electronic device is removed from the network, the electronic device instructed to remove the electronic device from the network uses the information for authenticating the wearer to confirm that the removal operator is valid, and then the control device Send a removal request to. The control device gives the removal permission to the electronic device to be removed on condition that the inputted wearer secret information matches the wearer secret information stored in its nonvolatile storage device (FIG. 16). The information (the wearer authentication information, the public key, the secret key, and the public key signature) related to the electronic device to be removed, which is held in its own nonvolatile storage device, is deleted. The electronic device to which the removal permission is granted performs authentication communication for deleting the public key exchanged with the mutual authentication partner stored in its own nonvolatile storage device, and the public key of the mutual authentication partner and its signature. After erasing, the public key and the public key signature given from the control device and the specific public key are erased.

  According to the above, the public key, the private key, and the public key for the electronic device based on information such as a password for the control device to authenticate the wearer according to the attachment of the electronic device to the network Generate a signature for. The generated public key with signature and the public key of the control device for signature authentication are distributed and held to the electronic device and the electronic device to be mutually authenticated. Therefore, the electronic device does not need to have the public key, the secret key, the public key signature, and the public key of the certificate authority in advance as in item 1. Therefore, a function to suppress unauthorized removal of an electronic device by using a private signature on the network without the intervention of a certificate authority that issues a public key or a public key signature to be held in the electronic device in advance is realized. be able to. Other functions and effects are the same as those of the contract 1.

[11] <Instruction to delete public key of device to be removed>
In the network system according to Item 10, when the electronic device deletes the mutual authentication partner's public key and its signature stored in its nonvolatile storage device, the electronic device has its own public key and A command for instructing deletion of the signature is issued (FIG. 8).

  As a result, when the electronic device removal process is performed, it is possible to easily instruct the matching of the public keys that mutually connect the electronic devices remaining under the network permission.

[12] <Delete public key of device to be removed>
In the network system according to Item 11, in response to the delete command, the electronic device deletes the public key and the signature of the command requesting electronic device from its nonvolatile storage device (FIG. 8).

  Thereby, it is possible to easily realize the matching of the public key.

[13] <Mutual authentication>
Item 14. The network system according to any one of Items 10 to 12, wherein the mutual authentication is information encrypted with another electronic device to which the electronic device is subjected to mutual authentication using a public key of the other party. Information obtained by exchanging data as a shared key, and the encrypted information sent from the partner electronic device sent to the partner electronic device by sending information obtained by encrypting the predetermined information using the acquired shared key Is decrypted using the shared key, and the authentication result is validated when the information obtained thereby matches the predetermined information (FIG. 6).

  Thereby, messages using the shared key can be exchanged between electronic devices that have performed mutual authentication.

[14] <Tampering suppression of non-volatile storage device>
In the network system according to any one of Items 10 to 13, when the nonvolatile storage device holds the public key of another electronic device and its signature, all the electronic devices are subject to mutual authentication. The nonvolatile storage device is prohibited from being rewritten until a valid authentication result by mutual authentication is obtained with the electronic device.

  It becomes difficult to tamper with the public key held in the nonvolatile storage device of the electronic device that has been illegally removed.

[15] <Electronic device in parallel relationship>
Item 15. The network system according to any one of Items 10 to 14, wherein one electronic device connected to the network is a target of mutual authentication for all other electronic devices.

  It is suitable for a small network configuration.

[16] <Electronic device related to hierarchy>
In the network system according to any one of Items 10 to 14, the electronic device includes an upper electronic device and a lower electronic device corresponding to the electronic device, and the lower electronic device uses the upper electronic device as a mutual authentication target.

  Since the lower electronic device can limit the upper electronic device to a mutual authentication target, it is suitable for a large-scale network configuration. Furthermore, since the mutual authentication target is limited, the storage capacity of the nonvolatile storage device that stores the public key and the like can be reduced. Further, there is no problem whether the upper electronic device is either the control device or another electronic device.

[17] <Registered overseas device list>
In the network system of Item 16, the upper electronic device creates a public key list of lower electronic devices connected to the network at a predetermined timing, and the public key list created this time and the public key list created last time are Changes in devices connected to the network are detected by comparison. The electronic device supplies the communication device of the external network as a device list connected to the network, and registers the result every time the public key list is compared.

  The communication device can search for an electronic device that has been illegally removed by transmitting change information of the connected device to a tracking organization of the theft device via an external network.

[18] <Adoption of private signature>
In the network system according to any one of Items 10 to 17, the electronic device and the control device are in-vehicle devices, and the specific public key and the specific secret key are key information not signed by a certificate authority, and authenticate the wearer. The information for this is confidential information held by the wearer of the electronic device.

[19] <Theft deterrence method using certificate authority signature>
A theft deterrent method according to another embodiment of the present invention is connected to a network and has a unique private key, a public key, a signature of the public key, and a public key of a certificate authority used to decrypt the signature This is a method for suppressing theft of electronic devices, and includes electronic device attachment authentication control processing, mutual authentication control processing between electronic devices, and electronic device removal authentication control processing.

  The electronic device mounting authentication control process holds information for authenticating the wearer when the electronic device that does not hold the information for authenticating the wearer is activated, and performs mutual authentication with the electronic device and the electronic device. This is a process in which the target electronic device exchanges its own public key and its signature with each other and holds the other party's legitimate public key, thereby making the electronic device ready for the required operation.

  The mutual authentication control process includes a public key of another electronic device held mutually between another electronic device that is subject to mutual authentication when the electronic device holding information for authenticating the wearer is activated. This processing is to make the electronic device in a state where the required operation can be continued on the condition that the mutual authentication using is performed and the validity of the electronic device of the other party is confirmed.

  In the removal authentication control process, when the electronic device is removed from the network, the wearer is authenticated depending on whether or not the information given from the outside matches the information for authenticating the wearer held inside. After confirming that the worker is valid, the information for the wearer authentication and the information on the public key of the other electronic device for mutual authentication are invalidated from the electronic device to be removed.

  According to this method, the electronic device held in advance by the electronic device is authenticated by using the public key with the signature and the public key of the certificate authority, so that the electronic device is illegally removed in the same manner as described in the item 1. Even if the electronic device is connected to another network, the electronic device does not operate normally, so that the electronic device connected to the network can be prevented from being stolen. Further, the unauthorized removal prevention function is not invalidated by mutual authentication with a fake device, and there is no possibility that the unauthorized removal is erroneously detected and disabled.

[20] <Theft deterrence method using private signature>
A theft deterrent method according to another embodiment of the present invention uses a control device that holds a specific private key and a specific public key used to generate a signature to be given to an electronic device connected to a network. A method for suppressing theft, including electronic device attachment authentication control processing, mutual authentication control processing between electronic devices, and electronic device removal authentication control processing.

  When the information for authenticating the wearer that is not held in the control device is input, the wear authentication control process is based on the information for the control device to hold and authenticate the wearer. Generate a public key and a private key of the corresponding electronic device, generate a signature of the public key using the specific private key, and authenticate the wearer with the generated public key, the public key signature, and the specific public key A first attachment authentication control process to be given to the electronic device corresponding to the information to be performed, and the electronic device to which the public key and the public key signature and the specific public key are newly given from the control device The public key obtained by decrypting with the specific public key and the signature of the public key in its non-volatile storage device, and the public key and another electronic device to be mutually authenticated Exchange signature of public key A second mounting authentication control process in which the public key is stored in its own nonvolatile storage device on the condition that the input public key is confirmed and the validity of the input public key is confirmed. The public key is stored in its own non-volatile storage device on condition that the other electronic device inputted by exchanging the public key and its signature confirms the validity of the public key inputted from the other party. 3 mounting authentication control processing.

  In the mutual authentication control process, an electronic device holding its own public key and public key signature given from the control device is mutually exchanged with another electronic device that is subject to mutual authentication at the time of activation. This is a process in which a required operation can be continued on condition that mutual authentication using a public key of another electronic device held is performed to confirm the validity of the other electronic device.

  In the removal authentication control process, the control device instructed to remove the electronic device from the network is subject to removal on the condition that the inputted wearer secret information matches the wearer secret information held by itself. A first removal authentication control process for granting removal permission to the electronic device, and a second for deleting the public key and the signature of the mutual authentication partner stored in its non-volatile storage by the electronic device to which the removal permission has been given And removal authentication control processing.

  According to this method, since it is not necessary for the electronic device to have a public key with a signature issued by a certificate authority or the like in advance, the electronic device is illegally used in the same manner as in item 19 using a private signature on the network. It is possible to realize a function for suppressing removal.

2. Details of Embodiments Embodiments will be further described in detail.

Embodiment 1
In the first embodiment, an in-vehicle network system that performs mounting authentication, mutual authentication, and removal authentication using a signature of a certificate authority will be described as an example.

[One-layer network system]
FIG. 2 illustrates a schematic configuration of a network system according to an embodiment of the present invention. Here, an example is a one-layer network configuration in which a plurality of electronic devices 1, 2, 3, and X are connected to the network 4 in parallel. The network 4 is not particularly limited, but is, for example, a CAN (Controller Area Network) to which an ECU (Electric Control Unit) mounted in an automobile is connected. The electronic devices 1, 2, 3, and X may be ECUs or devices such as car navigation devices, audio devices, and telephone sets.

  FIG. 3 illustrates a configuration for performing wearer authentication of the device X, authentication of another electronic device, message authentication with another electronic device, and the like as the configuration of the electronic device X. Illustrations of configurations that differ depending on the function or application of the electronic device X such as a device are omitted. In FIG. 3, the electronic device X includes a data processing device 10, a memory unit 20 including a volatile memory such as SRAM and a non-volatile memory such as an electrically rewritable flash memory, and a network connected to the network 4. An interface unit 30 is provided, and in addition, a display unit and an audio reproduction unit corresponding to a function or application are provided.

  The non-volatile memory 20 holds in a storage area 25 a public key 21, a private key 22, a public key signature 23, and a public key 24 of the certification authority that are unique to the electronic device X issued from a predetermined certification authority. ing. The public key signature 23 is information obtained by encrypting the public key with the private key of the certificate authority, and can be decrypted using the public key 24 of the certificate authority. The public key 24 of the certificate authority is of course common to all the electronic devices 1, 2, 3, X.

  In addition, the nonvolatile memory 20 stores an area 26 for storing a public key exchanged with another electronic device to be mutually authenticated, which will be described later, and a storage area 27 for storing confidential information received from the wearer of the electronic device X. And a storage area 28 storing a program executed by the data processing apparatus 10.

  The nonvolatile memory 20 is prevented from being illegally read and tampered with, and is controlled by a program stored in the area 20, for example.

  The data processing apparatus 10 is configured as a program processing apparatus having, for example, a CPU (central processing unit), an accelerator, a RAM (random access memory), and the like, and has, for example, a wearer authentication calculation unit 11 and an authentication processing calculation unit 12 as an accelerator. Then, based on the control of the CPU, the electronic device mounting authentication control processing, the mutual authentication control processing between the electronic devices, the electronic device removal authentication control processing, and the like are performed.

  The other electronic devices are basically the same in configuration as the authentication function other than its original function as shown in FIG.

  FIG. 1 illustrates an operation sequence from when an electronic device is connected to the in-vehicle network to when it is removed from the in-vehicle network. After the electronic device is connected to the in-vehicle network, the wearer authentication process and the mutual authentication process are completed and normal operation is enabled, until the electronic device is specified to be removed from the in-vehicle network, the electronic device is shown in the normal operation The power is turned off in a possible state.

  When the electronic device is activated, it is determined in step 100 whether or not the wearer secret information is stored in the storage area 27 of the nonvolatile memory 20. When the electronic device is first connected to the in-vehicle network, since the wearer secret information is not stored, the process proceeds to steps 200 and 300, and the wearer secret information and the public key of the other electronic device are registered. When the electronic device is connected to the in-vehicle network and is activated for the second time or later, since the wearer secret information is stored, the process proceeds to steps 101, 400, and 102, and all stored in the storage area 26 of the nonvolatile memory 20 Perform mutual authentication with the device corresponding to the public key.

[Installer registration process and public key registration process]
If the wearer secret information is not stored in the storage area 27 of the nonvolatile memory 20 in step 100, the wearer registration process 200 and the public key registration process 300 are performed.

  FIG. 4 shows a specific example of public key registration processing. For example, if the electronic device X is newly connected to the network 4 this time, the electronic device X exchanges a public key with other electronic devices 1, 2, and 3 on the network. FIG. 4 illustrates processing for exchanging a public key between the electronic device 1 and the electronic device 2. The electronic device 1 sends its own public key # 1 and the signature of the public key # 1 to the electronic device 2, and the electronic device 2 that has received this verifies the signature of the public key # 1 with the public key of the certificate authority. If the public key # 1 is valid, the public key # 1 is stored in the non-volatile memory area 26 together with the ID of the electronic device 1. This time, the electronic device 2 sends its own public key # 2 and the signature of the public key # 2 to the electronic device 1, and the electronic device 1 that has received this verifies the signature of the public key # 2 with the public key of the certificate authority. If the public key # 2 is valid, the public key # 2 key is stored in the area 26 of the nonvolatile memory 20 together with the ID of the electronic device 2.

  FIG. 5 shows a specific example of the wearer registration process. First, when the electronic device to be mounted is provided with a wearer secret information input means such as a numeric keypad ("yes" in step 201), the wearer secret information is input using this ( 202), the input wearer secret information is stored in the storage area 27 of the nonvolatile memory 20. Although not specifically shown. When the data processing apparatus 10 writes the wearer secret information in the storage area 27, some of the bits are used as a write state flag to indicate that the information has been written, and the write state flag is referred to in the determination in the flag step 100. The

When there is no input means, the wearer registration process in step 200 ends. Subsequently, the public key registration process described in FIG. 4 is performed to connect the electronic device to the network 4, and the wearer secret information input from the other electronic device having the input means that has completed the mutual authentication is obtained. The wearer secret information received and received by encrypted communication using the shared key sent to the electronic device is stored in the storage area 27 of the nonvolatile memory 20.
[Mutual authentication with each device]
FIG. 6 shows an example of an authentication operation that electronic devices mutually perform using the shared key shared in the public key registration process 300. Here, an example in which the electronic device 1 and the electronic device 2 authenticate each other is shown. The electronic device 1 generates a random number # 1, encrypts it with the public key # 2, and transmits the encrypted random number # 1 to the electronic device 2 (TR1). The electronic device 2 takes out the random number # 1 by decrypting the encrypted random number # 1 with the secret key # 2. Further, the electronic device 2 generates a random number 2, encrypts it with the public key # 1, and transmits the encrypted random number # 2 to the electronic device 1 (TR2). At this time, the electronic device 2 holds the random number 1 and the random number 2 as one shared key # 1 # 2 in the work area.

  The electronic device 1 that has received the encrypted random number # 2 decrypts it with the private key 1 and takes out the random number # 2, and, like the electronic device 2, uses the random number 1 and the random number 2 as one shared key # 1 # 2. Keep in your work area. Further, the electronic device 1 generates a random number # 3, encrypts it with the shared key # 1 # 2, and transmits it to the electronic device 2 (TR3).

  The electronic device 2 takes out the random number # 3 encrypted with the shared key # 1 # 2 and sends it back to the electronic device 1 (TR4), generates a random number # 4, and encrypts it with the shared key # 1 # 2. It transmits to the electronic device 1 (TR5).

  The electronic device 1 confirms that the random number # 3 has been sent back, and writes the shared key # 1 # 2 of the work area in correspondence with the ID of the electronic device 2 in its storage area 26 and the corresponding RAM area. The random number # 4 is decrypted and sent back to the electronic device 2.

  The electronic device 2 confirms that the random number # 4 has been sent back, and writes the shared key # 1 # 2 of the work area in correspondence with the ID of the electronic apparatus 1 in its own storage area 26 and the corresponding RAM area.

  As a result, the electronic device 1 and the electronic device 2 can share the shared key # 1 # 2 by specifying the other party's ID.

  The electronic device already connected to the network 4 holds the wearer secret information and holds the public key exchanged in the public key registration processing 300. In the mutual authentication control process, the electronic device holding the information for authenticating the wearer uses the public key of the other electronic device held mutually with another electronic device that is subject to mutual authentication at the time of startup. This is a process in which the electronic device can be operated by an original function such as car navigation (normal operation) on the condition that the mutual authentication used is confirmed and the validity of the electronic device of the other party is confirmed. According to FIG. 1, all electronic devices connected to the network 4 repeat the mutual authentication process (400) until there is no public key for which the mutual authentication process has not been completed (“no” in step 101). Normal operation is possible only after mutual authentication with all electronic devices is valid (“yes” in step 102), and normal operation is impossible if any one of the mutual authentication results is invalid. (“No” in step 102).

  The mutual authentication process in step 400 is, for example, the process described with reference to FIG. Whether or not there is a public key that has not been mutually authenticated in step 101 is, for example, whether the public key is held in the storage area 26 and the shared key is held in the corresponding RAM area corresponding to the ID of the mutual authentication partner electronic device. What is necessary is just to discriminate by whether or not. The mutual authentication process is executed each time the electronic device is powered on, and it is determined whether a change has occurred in the electronic device connected to the network 4. Since the shared key is regenerated each time the power is turned on, It is preferable to hold it in the RAM area.

[Removal authentication control process]
When the electronic device is removed from the network 4, a removal authentication control process is performed. In the removal authentication control process, when the electronic device is removed from the network, the removal is performed by authenticating the wearer depending on whether or not the information given from the outside matches the wearer secret information held in the storage device 27. After confirming that the operator is legitimate, the wearer confidential information and the public key information of the other electronic device for mutual authentication are erased from the electronic device to be removed, and the removal is permitted. According to FIG. 1, for example, it is determined whether or not the device is to be removed depending on whether or not the removal button of the electronic device has been operated (103). The removal process 500 for revoking the public key is performed, and after waiting for the removal approval (removal OK) (104), the operation power of the electronic device is shut off. At the same time, other electronic devices whose mutual authentication partner is the electronic device to be removed wait for an erasure request from the electronic device to be removed ("yes" in step 105), and are held by themselves. A public key erasing process 600 is performed to invalidate the public key of the electronic device to be removed.

  FIG. 7 shows a specific example of the removal process 500. First, through steps 501 to 504 in which processing similar to the operation described in FIG. 5 is performed, the wearer secret information of the removal operator is input. It is determined whether or not the inputted wearer secret information matches the wearer secret information held in the storage area 27 of the device to be removed (506).

  If they match, the public key deletion processing 508 is repeated until there is no electronic device for which the public key deletion processing 508 has not been completed with other electronic devices that have exchanged public keys (507).

  FIG. 8 shows a specific example of the public key deletion process 508. First, a shared key is obtained in the same manner or in a simplified manner with other electronic devices that have exchanged public keys. Subsequently, the erasure request is encrypted with the corresponding shared key between each of the other electronic devices to which the electronic device to be removed has exchanged the public key and given to the other electronic device. Decrypts it with the shared key, receives the erasure request, erases the public key of the target electronic device from the non-volatile memory, encrypts the erasure request receipt notification with the shared key, returns it to the target electronic device, and removes it The electronic device decrypts and receives the erasure request receipt notification with the shared key. After that, the public key of the other electronic device stored in the non-volatile memory 26 of the device to be removed is deleted, and a deletion process notification is transmitted to the other electronic device.

  An example is a process of issuing an erasure request from the electronic device 1 to the electronic device 2 after performing a process of sharing the shared key # 1 # 2 between the electronic device 1 to be removed and another electronic device 2 by a simplified process. Has been. It is not necessary to repeat the process of generating a shared key with an electronic device that has a shared key with another electronic device that has exchanged a public key. The case where the public key must be generated in the public key erasure process 508 is only the case of an electronic device to be removed without shutting down the operation power supply once after being attached to the network 4.

  An erasure request is issued to another electronic device that has shared the public key with the electronic device to be removed and has performed the public key erasure process 508.

  In the public key erasure processing 508, if the erasure request reception notification cannot be received even after a predetermined time has passed from the electronic device sharing the public key, it is considered that there is some abnormality, and the public key for the other electronic device The erasure process is interrupted, and a public key erasure cancellation process (512) for canceling the already issued erasure request is issued to make it unsuitable to remove the electronic device to be removed. FIG. 9 shows an example in which the electronic device 1 instructs the electronic device 2 to cancel the public key deletion as an example of the public key deletion cancellation processing (512). That is, the electronic device 1 encrypts the erasure cancellation command with the shared key and transmits it to the electronic device 2, and the electronic device 2 decrypts it with the shared key and receives the erasure cancellation command. As a result, when the electronic device 2 has already received an erase request, the electronic device 2 cancels the request by an erase cancel command.

  The public key deletion processing 508 is repeated until there is no electronic device for which the public key deletion processing 508 has not been completed with other electronic devices whose public keys have been exchanged (step 507 “no”).

  Finally, in the electronic device to be removed, the confidential information of the wearer at that time is erased from the nonvolatile memory 20, and the removal process is completed (step 511).

  Thus, when an electronic device that has not been properly removed is forcibly removed from the network, the non-volatile storage device 20 has a public key exchanged with the electronic device that is the partner of mutual authentication along with the wearer secret information. Will remain. Therefore, even if an electronic device that has been removed from the network without being determined to be suitable for removal, that is, an electronic device that has been illegally removed, is reconnected to another network 4, the electronic device involved in unauthorized removal is owned by the electronic device. The public key does not completely match the public key that the electronic device that is the subject of mutual authentication processing on the new network, and is normally disabled. Even if it is installed in the system, it cannot be operated. Since the electronic device that has been illegally removed also holds the wearer secret information, it is not possible to proceed to the new public key registration process 300 in FIG. Further, since the non-volatile memory 20 cannot be rewritten to the storage area for the public key and the wearer secret information unless mutual authentication is completed, tampering with them is also prevented. Therefore, if an unauthorized person removes an electronic device from the network, the removal process from the network is not performed correctly, and the public key of another electronic device in the removed network environment remains as it is. In other words, when the electronic device is connected to another network and started up, mutual authentication becomes abnormal and normal operation is not possible. The stolen electronic device does not operate correctly, and theft of the electronic device can be suppressed.

  Since mutual authentication of electronic devices is performed using a legitimate public key, the unauthorized removal prevention function is not invalidated by mutual authentication with fake devices.

  Since it is possible to easily detect unauthorized removal by mutual authentication using a public key, it does not happen that unauthorized removal is detected by mistake and becomes inoperable.

<< Embodiment 2 >>
[Multi-layer network system]
A case will be described in which a one-layer network system that performs mounting authentication, mutual authentication, and removal authentication using a certificate authority signature according to the first embodiment is applied to a multi-layer network system.

  FIG. 10 illustrates a system configuration when applied to a multi-layer network system. In this case, the electronic devices connected to the network 4A include, for example, the upper electronic device 1A and the lower electronic devices 2A, 3A, XA for the electronic device 1A, and the lower electronic devices 2A, 3A, XA are the upper electronic devices. The device 1A is set as a mutual authentication target. This configuration is different from that of the first embodiment in that an electronic device connected to the network 4A has one electronic device as a target of mutual authentication for all other electronic devices, and is connected between all other electronic devices. The difference is that mutual authentication is not targeted. The electronic device 2A targets the electronic device 1A for the mutual authentication processing 400, the electronic device 3A targets the electronic device 1A for the mutual authentication processing 400, and the electronic device XA targets the electronic device 1A for the mutual authentication processing 400. 1A targets all other electronic devices 2A, 3A, and XA for mutual authentication processing 400. The electronic device 1A exchanges public keys with all the other electronic devices 2A, 3A, and XA, and holds those public keys # 2, # 3, and #X. Each of the electronic devices 2A, 3A, and XA Exchange the public key with the electronic device 1A and hold the public key # 1, and it is not necessary to exchange and hold the public key between the electronic devices 2A, 3A, and XA. The electronic device 1A functions as an authentication mast. Except for this difference, also in the second embodiment, the above-described attachment authentication control processing, mutual authentication control processing between electronic devices, and electronic device removal authentication control processing may be applied, and the contents remain unchanged. Detailed description thereof is omitted here. In particular, a relatively higher-layer electronic device connected to an electronic device in a lower layer performs a removal process 500 on the electronic device in a lower layer than itself.

  Although FIG. 10 illustrates a case where the number of layers of the hierarchical network is two, the number of layers may be three or more. The electronic devices 1A, 2A, 3A, and XA shown in FIG. 11 have a lower network interface unit (LIF) 30L connected to a lower layer relative to FIG. 1 and an upper network interface unit (UIF) connected to an upper layer. ) The difference is that both are provided with 30U. FIG. 11 representatively shows the configuration of the electronic device XA. The lower network interface unit 30L and the upper network interface unit 30U are connected to the data processing apparatus 10 and controlled.

  The configuration of the first embodiment applied to a one-layer network system is suitable for a small-scale network configuration. On the other hand, the configuration in which the electronic devices have a hierarchical relationship in the multi-layer network system is suitable for a large-scale network configuration because the lower electronic devices can limit the upper electronic devices to mutual authentication targets. Furthermore, since the mutual authentication target is limited, the storage capacity of the nonvolatile memory 20 for storing the public key and the like can be reduced.

<< Embodiment 3 >>
[Registered device list]
FIG. 12 shows a network system according to Embodiment 3 of the present invention. The network system shown here will be described using the multi-layer network system described in the second embodiment as an example. The upper electronic device 1A creates the public key list of the lower electronic device 2A connected to the network as an in-vehicle device list at a predetermined timing, and compares the in-vehicle device list created this time with the previously created in-vehicle device list When a change in the electronic device connected to the network is detected and it is determined that there is a stolen electronic device, the result is supplied to the communication device 5 to the external network. The communication device 5 can search for an electronic device that has been illegally removed by transmitting the change information of the in-vehicle device list to the tracking device 6 of the theft device via an external network. This is particularly suitable for a system using a public key issued by a predetermined certificate authority. The trusted organization 6 can also search for the location of the stolen electronic device based on the public key.

  The description of the present embodiment has been made based on a multi-layer network system. However, even in the one-layer network system of the first embodiment, any one electronic device is connected to the communication device 5 of the external network. What is necessary is just to have the function to communicate.

<< Embodiment 4 >>
In the fourth embodiment, a network system that performs mounting authentication, mutual authentication, and removal authentication using a private signature will be described.

  FIG. 13 illustrates a schematic configuration of a network system according to Embodiment 4 of the present invention. Here, a configuration in which a plurality of electronic devices 1B, 2B, and XB are connected in parallel to the network 4B is taken as an example. The difference from the first embodiment is that a specific electronic device is connected to the network as a control device without using a private key, public key, public key signature, and public key of the certification authority that have been issued in advance by the certification authority. Generating a public key, a private key, and a signature of the public key for the other electronic device. The public key and private key generated in this way, the method of using the public key signature, the authentication method by exchanging the public key by the electronic device, and the like are the same as those described in the first embodiment. In the following, differences from the first embodiment will be mainly described in detail. In order to facilitate understanding, attention is paid to a case where the electronic device 2B connected to the network is a control device, the electronic device 1B is already connected to the network 4B, and the electronic device XB is newly connected this time.

[Create private key, public key and signature]
The control device 2B is an electrical device that holds a specific private key (device 2B private key) and a specific public key (device 2B public key) used to generate a signature to be given to the electronic devices 1B and XB connected to the network 4B. A rewritable nonvolatile memory is included. Similarly to the above, this nonvolatile memory also takes into consideration prevention of unauthorized reading and alteration of stored information. The electronic device 1B already connected to the network includes a secret key (device 1B private key) for the electronic device 1B generated by the control device 2B, and a public key (device for the electronic device 1B generated by the control device 2B. 1B public key), the control device 2B holds the signature of the device 1B public key generated using the device 2B private key, and the device 2B public key used for signature verification in the nonvolatile memory 20_1B. The electronic device XB newly connected to the network has a device XB-based public key and a device XB-based secret key determined only by the device XB in the nonvolatile memory 20_XB.

  The control device 2B has an input unit 700 for inputting information for authenticating the wearer (wearer secret information). When the device XB is mounted on the network, the wearer inputs the wearer secret information to the control device 2B (ST1). When the wearer secret information that is not held in the nonvolatile memory 20_2B is input, the control device 2B holds this in the nonvolatile memory 20_2B, and the public key of the corresponding electronic device based on the wearer secret information A (device XB public key) and a secret key (device XB secret key) are generated (ST2). The control device 2B generates a signature of the device XB public key using the device 2B private key, and adds this signature to the device XB public key (ST3). Each processing of ST2 key generation and ST3 signature generation is performed by the data processing device 10_2B.

  Next, as illustrated in FIG. 14, the control device 23B receives the device XB base public key from the electronic device XB (ST4). The control device 2B encrypts the signed device XB public key, the device XB private key, and the device 2B public key using the device XB base public key of the received electronic device XB (ST5), and stores the encrypted information in the network 4B. To the electronic device XB. The electronic device XB decrypts the received encrypted information using the device XB base private key (ST6), and the device 2B public key, the signed device XB public key, and the device XB private key obtained thereby are stored in a nonvolatile memory. 20_XB. ST4 key reception and ST5 encryption are performed by the data processing device 10_2B of the control device 2B, and ST decryption is performed by the data processing device 10_XB of the electronic device XB.

[Exchange public key]
Next, as illustrated in FIG. 15, the electronic device XB sends the signed device XB public key to the device 1B (ST7), and the device 1B verifies the signature using the device 2B public key and adds the signature. The device XB public key is a key generated by the trusted device 2B, that is, the validity of the device XB public key attached to the signed device XB public key is confirmed (ST8). When the validity is confirmed, the device XB public key and its signature are stored in the nonvolatile memory 20_1B. Conversely, the electronic device 1B sends the signed device 1B public key to the electronic device XB (ST9), the device XB verifies the signature using the device 2B public key, and the signed device 1B public key is trusted. It confirms that the device 2B is a key generated, that is, the validity of the device 1B public key attached to the signed device 1B public key (ST10). When the validity is confirmed, the device 1B public key and its signature are stored in the nonvolatile memory 20_XB.

  As a result, the electronic device 1B already connected to the network 4B and the newly connected electronic device XB exchange and hold each other's device 1B public key and device XB public key, which are guaranteed to be valid by the control device 2B. can do. The processing up to this point corresponds to 300 and 200 in FIG. 1 and completes the attachment authentication control processing up to the public key exchange. Therefore, the electronic devices 1B and XB can perform the same mutual authentication control process as described above by performing the mutual authentication described with reference to FIG. 6 using these public keys.

[Allow electronic device removal]
FIG. 16 illustrates an operation procedure for obtaining a removal permission to be obtained when the electronic device is removed from the network. The acquisition permission corresponds to the determination result in step 506 of FIG.

  When removing the electronic device XB from the network 4B, the wearer inputs the wearer secret information to the control device 2B (ST11). The control device 2B checks whether or not the input confidential information is correct (ST12), and if it is correct, transmits a removal request to the electronic device 2B (ST13).

  Upon receiving the removal request, electronic device XB generates a random number (device XB random number) (ST14), and transmits the generated device XB random number to control device 2B (ST15). The control device 2B encrypts the received device XB random number with the device 2B private key (ST16), and transmits the encrypted device XB encrypted random number to the electronic device XB (ST17). The electronic device XB decrypts the device XB encrypted random number with the device 2B public key (ST8), determines whether or not the decrypted information matches the device XB random number, and generates a permission for removal if they match. This removal permission corresponds to the discrimination match in step 506 of FIG. Therefore, by using this determination result, the same removal control process as described above with reference to FIG. 7 and the like can be performed.

  According to the fourth embodiment, the control device 2B, based on the wearer authentication information for authenticating the wearer according to the attachment of the electronic device to the network, the public key, the secret key for the electronic device, And a signature for the public key. The generated public key with signature and the public key (device 2B public key) of the control device for signature authentication are distributed and held to the electronic device XB and the electronic device 1B to be subjected to mutual authentication. The Therefore, the electronic device connected to the network 4B does not need to have a public key, a secret key, a public key signature, and a certificate authority public key in advance as in the first embodiment. Therefore, a function to suppress unauthorized removal of an electronic device by using a private signature on the network without the intervention of a certificate authority that issues a public key or a public key signature to be held in the electronic device in advance is realized. be able to. In addition, the same operational effects as those of the other embodiments can be obtained.

  Further, only the control device 2B obtains a signature from the certificate authority, and uses the signature obtained from the certificate authority when creating the signature of the lower electronic device, thereby increasing the reliability of the signature given to each lower electronic device. Is possible.

  Although the invention made by the present inventor has been specifically described based on the embodiments, it is needless to say that the present invention is not limited thereto and can be variously modified without departing from the gist thereof.

  For example, an electronic device is not limited to a device mounted on an automated person, and may be an electronic device mounted on a vehicle of any transportation system such as a train, a ship, an aircraft, or a device mounted on a production facility. The subject of the present invention.

1, 2, 3, X Electronic device 4 Network 10 Data processing device 20 Non-volatile memory 30 Network interface unit 21 Public key 22 Private key 23 Public key signature 24 Public key of authentication pole 1A Upper electronic device 2A, 3A, XA Lower level electronic device 4A Hierarchical network 30U Upper network interface unit 30L Lower network interface unit 5 Communication device outside network 2B Control device 1A, 3A, XA Electronic device 4B Network 10_1B, 10_2B, 10_XB Data processing device 20_1B, 20_2B, 20_XB Non-volatile memory 4A hierarchical network

Claims (20)

A network system comprising electronic devices connected to a network,
The electronic device has a rewritable nonvolatile storage device that holds a private key and public key unique to the electronic device, a signature of the public key by a certificate authority, and a public key of the certificate authority,
An electronic device that does not hold information for authenticating the wearer inputs information for authenticating the wearer at the time of start-up and stores the information in its own nonvolatile storage device. The public key and the signature of the public key are exchanged and input with the electronic device, and the public key is stored in its nonvolatile storage device on condition that the validity of the input public key is confirmed. The required operation can be continued,
The other electronic device inputted by exchanging the public key and the signature stores the public key in its own nonvolatile storage device on condition that the validity of the inputted public key is confirmed,
The electronic device holding the information for authenticating the wearer is mutually authenticated using the public key of the other electronic device held mutually with another electronic device that is subject to mutual authentication at the time of activation. On the condition that the correctness of the other electronic device is confirmed and the required operation can be continued,
The electronic device instructed to be removed from the network is stored in the nonvolatile storage device on condition that the inputted wearer secret information matches the wearer secret information stored in its own nonvolatile storage device. A network system that erases the public key and wearer secret information of the mutual authentication partner.   When the electronic device erases the mutual authentication partner's public key and the wearer secret information stored in its nonvolatile storage device, the electronic device instructs the mutual authentication partner's electronic device to erase its public key. The network system according to claim 1, wherein:   The network system according to claim 2, wherein the electronic device erases the public key of the electronic device requesting the command from its nonvolatile storage device in response to the erase command.   In the mutual authentication, the electronic device obtains, as a shared key, predetermined information obtained by exchanging information encrypted with each other's public key with the electronic device to be subjected to mutual authentication. Then, information obtained by encrypting predetermined information using the acquired shared key is sent to the partner electronic device, and the encrypted information returned from the partner electronic device is decrypted using the shared key, and thus obtained. The network system according to claim 1, which is a process for validating an authentication result when information matches the predetermined information.   When the non-volatile storage device holds the secret information, the electronic device is in a non-volatile state until a valid authentication result by mutual authentication is obtained with all electronic devices to be subjected to mutual authentication. The network system according to claim 1, wherein the volatile storage device is prohibited from being rewritten.   The network system according to claim 1, wherein one electronic device connected to the network targets all other electronic devices for mutual authentication. The electronic device includes an upper electronic device and a lower electronic device for the electronic device,
The network system according to claim 1, wherein the lower electronic device has a higher electronic device as a mutual authentication target.   The upper electronic device creates a public key list of lower electronic devices connected to the network at a predetermined timing, and connects to the network by comparing the public key list created this time with the public key list created last time The network system according to claim 7, wherein the change is detected and the result is supplied to a communication device to an external network. The electronic device is an in-vehicle device,
The private key unique to the electronic device, the public key, the signature of the public key by the certificate authority, and the public key of the certificate authority are information issued by the certificate authority,
The network system according to claim 1, wherein the information for authenticating the wearer is secret information held by the wearer of the electronic device. A network system having a control device and an electronic device for controlling connection and removal of the electronic device to the network,
The electronic device has a rewritable nonvolatile storage device,
The control device has a non-volatile storage device that holds a specific secret key and a specific public key used for generating a signature to be given to an electronic device connected to a network,
When the control device inputs information for authenticating a wearer not held in its own nonvolatile storage device, the control device stores the information in its own nonvolatile storage device and authenticates the wearer. And generating a public key and a private key of the corresponding electronic device based on the information of the electronic device, generating a signature of the public key using the specific private key, and generating the generated public key, the public key signature, and the specific public key Give the electronic equipment corresponding to the information to authenticate the wearer,
The electronic device to which the public key and the public key signature and the specific public key are newly given from the control device, the public key obtained by decrypting the public key signature with the specific public key, and the public key signature Is stored in its own non-volatile storage device, and the public key and the signature of the public key are exchanged and input with another electronic device subject to mutual authentication. The public key is stored in its own nonvolatile storage device on the condition that it is confirmed that the required operation can be continued,
The other electronic device inputted by exchanging the signature with the public key stores the public key in its nonvolatile storage device on condition that the validity of the public key inputted from the other party is confirmed,
The electronic device holding its own public key and the public key signature given from the control device is another electronic device that is mutually owned with another electronic device that is subject to mutual authentication at startup. The required operation can be continued on the condition that the authenticity of the other electronic device is confirmed by performing mutual authentication using the public key,
The control device, which is instructed to remove the electronic device from the network, is subject to removal on the condition that the inputted wearer secret information matches the wearer secret information stored in its nonvolatile storage device. Give the device permission to remove,
A network system in which an electronic device to which removal permission is given erases the public key and the signature of the mutual authentication partner stored in its nonvolatile storage device.   When the electronic device erases the mutual authentication partner's public key and its signature stored in its nonvolatile storage device, the electronic device instructs the mutual authentication partner's electronic device to erase its public key and its signature. The network system according to claim 10 which issues a command.   12. The network system according to claim 11, wherein the electronic device erases the public key and signature of the command requesting electronic device from its nonvolatile storage device in response to the erase command.   In the mutual authentication, predetermined information obtained by exchanging information encrypted using the other party's public key with another electronic device to be subjected to mutual authentication is shared key. The information obtained by encrypting the predetermined information using the acquired shared key is sent to the other electronic device, and the encrypted information returned from the other electronic device is decrypted using the shared key, thereby The network system according to claim 10, wherein the authentication result is valid when the obtained information matches the predetermined information.   When the non-volatile storage device holds the public key of another electronic device and its signature, the electronic device is authorized by mutual authentication with all electronic devices subject to mutual authentication. The network system according to claim 10, wherein the nonvolatile storage device is prohibited from being rewritten until a result is obtained.   The network system according to claim 10, wherein one electronic device connected to the network targets all other electronic devices for mutual authentication. The electronic device includes an upper electronic device and a lower electronic device for the electronic device,
The network system according to claim 10, wherein the lower electronic device targets the upper electronic device as a mutual authentication target.   The upper electronic device creates a list of lower electronic devices connected to the network at a predetermined timing, and changes in devices connected to the network by comparing the public key list created this time with the public key list created last time The network system according to claim 16, wherein the network system is detected and the result is supplied to a communication device to an external network. The electronic device and the control device are in-vehicle devices,
The specific public key and the specific secret key are key information not signed by a certificate authority,
The network system according to claim 10, wherein the information for authenticating the wearer is secret information held by the wearer of the electronic device. A method of suppressing theft of an electronic device that is connected to a network and has a unique private key, a public key, a signature of the public key, and a public key of a certificate authority used for decrypting the signature,
Including electronic device mounting authentication control processing, mutual authentication control processing between electronic devices, and electronic device removal authentication control processing,
The electronic device mounting authentication control process holds information for authenticating the wearer when the electronic device that does not hold the information for authenticating the wearer is activated, and performs mutual authentication with the electronic device and the electronic device. The target electronic device exchanges its public key and its signature with each other and holds the other party's legitimate public key, thereby making the electronic device ready for the required operation.
The mutual authentication control process includes a public key of another electronic device held mutually between another electronic device that is subject to mutual authentication when the electronic device holding information for authenticating the wearer is activated. On the condition that the mutual electronic authentication is performed and the validity of the electronic device of the other party is confirmed.
In the removal authentication control process, when the electronic device is removed from the network, the wearer is authenticated depending on whether or not the information given from the outside matches the information for authenticating the wearer held inside. Theft deterrence method that invalidates information for wearer authentication and public key information of other electronic devices for mutual authentication from the electronic device to be removed after confirming that the operator is valid . A method of suppressing theft of an electronic device using a control device that holds a specific private key and a specific public key used to generate a signature to be given to an electronic device connected to a network,
Including electronic device mounting authentication control processing, mutual authentication control processing between electronic devices, and electronic device removal authentication control processing,
When the information for authenticating the wearer that is not held in the control device is input, the wear authentication control process is based on the information for the control device to hold and authenticate the wearer. Generate a public key and a private key of the corresponding electronic device, generate a signature of the public key using the specific private key, and authenticate the wearer with the generated public key, the public key signature, and the specific public key First mounting authentication control processing to be given to the electronic device corresponding to the information to do,
The public key obtained by decrypting the signature of the public key with the specific public key by the electronic device to which the public key and the public key signature and the specific public key are newly given from the control device and the signature of the public key Is stored in its own non-volatile storage device, and the public key and the signature of the public key are exchanged and input with another electronic device subject to mutual authentication. A second mounting authentication control process in which the public key is stored in its own nonvolatile storage device on the condition that it is confirmed and the required operation can be continued;
The public key is stored in its own non-volatile storage device on condition that the other electronic device inputted by exchanging the public key and its signature confirms the validity of the public key inputted from the other party. Mounting authentication control processing,
In the mutual authentication control process, an electronic device holding its own public key and public key signature given from the control device is mutually exchanged with another electronic device that is subject to mutual authentication at the time of activation. It is a process that allows the required operation to be continued on the condition that the authenticity of the other electronic device is confirmed by performing mutual authentication using the public key of the other electronic device possessed,
In the removal authentication control process, the control device instructed to remove the electronic device from the network is subject to removal on the condition that the inputted wearer secret information matches the wearer secret information held by itself. A first removal authentication control process for giving the electronic device removal permission;
A theft deterrence method in which the electronic device to which the removal permission is given includes a second authentication control process for deleting the public key of the mutual authentication partner stored in its own nonvolatile storage device and its signature.

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