Wire harness, detection system, and detection method

Abstract

This wire harness connects communication between a first communication unit and a second communication unit. The wire harness includes a first connector, a second connector, and a cable provided between the first connector and the second connector. The cable includes a plurality of electric wires that include an electric wire for detection, and a conductor that functions as a ground for the electric wire for detection. The electric wire for detection does not have a shield, and is disposed such that impedance of the electric wire for detection is a prescribed value.

Description

Wire harness, detection system, and detection method

[0001] The present disclosure relates to a wire harness, a detection system, and a detection method. This disclosure claims priority to Japanese Patent Application No. 2023-075921, filed May 2, 2023, and incorporates by reference all of the contents of said Japanese application.

[0002] Vehicles are equipped with various on-board devices. These on-board devices include various ECUs (Electronic Control Units) that control functions necessary for the vehicle, such as steering and braking. These ECUs are connected to each other to form a network. Each ECU communicates with each other via this network to realize basic vehicle functions such as "driving," "turning," and "stopping." Wire harnesses are usually used for communication between on-board devices.

[0003] Such in-vehicle devices require technology to prevent hacking or data tampering of the in-vehicle devices (ECUs). Patent Document 1, listed below, proposes technology to prevent unauthorized access to in-vehicle connectors.

[0004] The technology described in Patent Document 1 relates to a security structure for a connector. This security structure includes a protective cover that is attached to cover the mated connector. The protective cover can be released only with a dedicated tool. This protective cover prevents easy removal of a wire harness connected to the connector of the on-board device. Therefore, the security structure described in Patent Document 1 can prevent unauthorized access to the on-board device by replacing the connector or wire harness, or by probing the communication line, etc.

[0005] International Publication No. 2017 / 047567

[0006] According to an aspect of the present disclosure, there is provided a wire harness for connecting a first communication unit and a second communication unit, the wire harness including a first connector, a second connector, and a cable arranged between the first connector and the second connector. The cable includes a plurality of electric wires including a detection electric wire and a conductor that functions as a ground for the detection electric wire. The detection electric wire is an unshielded electric wire and is arranged so that the impedance of the detection electric wire is a predetermined value.

[0007] The present disclosure can be realized not only as a wire harness, a detection system, or a detection method including such a characteristic configuration, but also as a program for causing a computer to execute the characteristic steps performed by the detection system or the detection method, or a recording medium on which the program is recorded. Furthermore, the present disclosure can be realized as other systems or devices including the wire harness or the detection system.

[0008] FIG. 1 is a diagram illustrating an example of the configuration of a communication system according to a first embodiment. FIG. 2 is a diagram schematically illustrating a cross section of the wire harness shown in FIG. 1 taken along line A-A. FIG. 3 is a cross section illustrating an example of the configuration of the detection wire shown in FIG. 2. FIG. 4 is a cross section illustrating an example of the configuration of the wire to be protected shown in FIG. 2. FIG. 5 is a block diagram illustrating an example of the configuration of the in-vehicle device shown in FIG. 1. FIG. 6 is a block diagram illustrating an example of the functional configuration of a detection device mounted on the in-vehicle device. FIG. 7 is a diagram illustrating the communication system shown in FIG. 1. FIG. 8 is a cross section illustrating an example of the configuration of a wire harness according to a modified example. FIG. 9 is a cross section illustrating an example of the configuration of a wire harness according to a second embodiment. FIG. 10 is a cross section illustrating an example of the configuration of the wire to be protected shown in FIG. 9. FIG. 11 is a diagram illustrating an example of the configuration of a communication system according to a third embodiment. FIG. 12 is a diagram schematically illustrating a cross section of the wire harness shown in FIG. 11 taken along line B-B. Fig. 13 is a diagram for explaining the communication system shown in Fig. 11, and the diagram of the cable portion of the wire harness is a schematic plan view in which the upper layer portion of the detection wire is omitted. Fig. 14 is a diagram showing an example of the configuration of a communication system according to a fourth embodiment. Fig. 15 is a diagram showing a schematic cross-section of the wire harness shown in Fig. 11 taken along line CC. Fig. 16 is a diagram showing an example of the configuration of a communication system according to a fifth embodiment. Fig. 17 is a diagram for explaining the communication system shown in Fig. 16, and the diagram of the cable portion of the wire harness is a diagram showing a schematic cross-section of the wire harness shown in Fig. 16 taken along line DD.

[0009] [Problem to be Solved by the Present Disclosure] The security structure described in Patent Document 1, which includes a protective cover, is easily addressed because the security measures taken are readily apparent from the exterior. For example, if the protective cover is physically destroyed, unauthorized access to the in-vehicle device becomes possible.

[0010] The present disclosure has been made to solve such problems, and one object of the present disclosure is to provide a wire harness, a detection system, and a detection method that can improve communication security with a configuration that is not apparent from the outside.

[0011] Effect of the Present Disclosure According to the present disclosure, it is possible to provide a wire harness, a detection system, and a detection method that can improve communication security with a configuration that is not apparent from the outside.

[0012] [Description of Embodiments of the Present Disclosure] Preferred embodiments of the present disclosure will be listed and described below. At least some of the embodiments described below may be combined in any combination.

[0013] (1) A wire harness according to a first aspect of the present disclosure is a wire harness that connects communication between a first communication unit and a second communication unit. The wire harness includes a first connector, a second connector, and a cable arranged between the first connector and the second connector. The cable includes a plurality of electric wires including a detection electric wire and a conductor that functions as a ground for the detection electric wire. The detection electric wire is an unshielded electric wire and is arranged so that the impedance of the detection electric wire is a predetermined value.

[0014] For example, the conductor may be stripped during probing for the purpose of stealing information, such as unauthorized access. Because the conductor functions as a ground for the detection wire, stripping the conductor changes the impedance of the detection wire. By detecting this change in impedance, probing of the wire harness can be detected. This improves communication security. Because communication security can be improved without using components such as protective covers that are easily visible from the outside, it is difficult to tell from the outside whether security measures have been taken.

[0015] (2) In the above (1), the plurality of electric wires may include a communication electric wire that is separate from the detection electric wire. By providing the detection electric wire separately from the communication electric wire, it is easy to arrange the detection electric wire so that its impedance becomes a predetermined value. This makes it easy to improve communication security.

[0016] (3) In the above (2), the communication wire may have a shield, which can prevent deterioration of communication performance.

[0017] (4) In the above (2) or (3), the impedance of the detection wire may be different from the impedance of the communication wire, which increases the degree of freedom in setting the impedance of the detection wire, thereby making it easier to improve communication security.

[0018] (5) In the above (1), the plurality of electric wires may include a communication electric wire, and the communication electric wire may include a detection electric wire. That is, the communication electric wire may also serve as a detection electric wire. This eliminates the need to provide a separate detection electric wire, thereby reducing the number of cables. Therefore, even when improving communication security, it is possible to suppress an increase in the cost of the wire harness.

[0019] (6) In any of the above (1) to (5), the cable may be flat. This allows the positional relationship between the conductor functioning as the ground and the detection wire to be easily fixed, making the impedance of the detection wire more stable. This makes it easier to detect changes in impedance, thereby improving the accuracy of detecting unauthorized access.

[0020] (7) In the above (6), the conductor may include a sheet-like conductor. This makes it easier to change the impedance of the detection wire during probing, thereby further improving the accuracy of detecting unauthorized access.

[0021] (8) In the above (7), the sheet-like conductor may include a first conductive sheet and a second conductive sheet, and the detection wire may be disposed between the first conductive sheet and the second conductive sheet. This allows the sheet-like conductor to be peeled off regardless of whether the flat cable is probed from the top or bottom, thereby enabling effective detection of changes in impedance of the detection wire. This further improves communication security.

[0022] (9) In any of the above (6) to (8), when a specific electric wire among the plurality of electric wires is a wire to be protected, the detection electric wire may be configured to be arranged on the same layer as the layer on which the electric wire to be protected is arranged. This allows the impedance of the detection electric wire to be changed more reliably during probing, thereby further improving communication security.

[0023] (10) In any of (6) to (8) above, the cable may have a laminated structure in which multiple electric wires are arranged in multiple layers, and the detection electric wire may be arranged in the outermost layer of the laminated structure. The outermost layer in the laminated structure is the first layer from which a sheet is peeled off during probing. Therefore, by arranging the detection electric wire in this layer, signs of unauthorized access can be easily detected. Furthermore, this configuration reduces wiring constraints on other electric wires. For example, if a specific electric wire among the multiple electric wires is designated as the electric wire to be protected, the electric wire to be protected can be arranged in a different layer from the detection electric wire.

[0024] (11) In any of the above (6) to (8), the cable may have a laminated structure in which multiple electric wires are arranged in multiple layers, and the detection electric wire may be arranged across the layers. This makes it easy to configure the detection electric wire so that its impedance changes during probing. Therefore, this configuration can further improve communication security.

[0025] (12) A detection system according to a second aspect of the present disclosure includes a wire harness and a detection device electrically connected to the wire harness. The wire harness includes a first connector, a second connector, and a cable arranged between the first connector and the second connector. The cable includes a plurality of electric wires including a detection electric wire and a conductor that functions as a ground for the detection electric wire. The detection electric wire is an unshielded electric wire and is arranged so that the impedance of the detection electric wire is a predetermined value. The detection device includes a measurement unit that measures the impedance of the detection electric wire and a determination unit that determines whether unauthorized communication is occurring based on the impedance measurement result by the measurement unit.

[0026] For example, if the conductor is stripped during probing for the purpose of stealing information, such as unauthorized access, the impedance of the detection wire changes. The measurement unit of the detection device measures the impedance of the detection wire. The determination unit determines whether unauthorized communication is being carried out through probing, etc., based on the impedance measurement results. This improves communication security. Since communication security can be improved without using components such as protective covers that are easily visible from the outside, it is difficult to tell from the outside whether security measures have been taken.

[0027] (13) In the above (12), the determination unit may be configured to determine that unauthorized communication is occurring in response to a change in impedance of the detection wire that is equal to or greater than a predetermined threshold value. This makes it easy to determine whether unauthorized communication is occurring through probing or the like.

[0028] (14) A detection method according to a third aspect of the present disclosure is a detection method for detecting unauthorized communication via a wire harness. The cable of the wire harness includes a plurality of electric wires, including a detection electric wire, and a conductor that functions as a ground for the detection electric wire. The detection electric wire is an unshielded electric wire and is arranged so that the impedance of the detection electric wire is a predetermined value. This detection method measures the impedance of the detection electric wire and determines whether unauthorized communication is taking place based on the measurement result. This not only improves communication security but also makes it difficult to tell from the outside whether security measures have been taken.

[0029] (15) In the above (14), the detection method may be configured to determine that unauthorized communication is occurring in response to a change in impedance of the detection wire that is equal to or greater than a predetermined threshold value. This makes it easy to determine whether unauthorized communication is occurring by probing or the like.

[0030] [Details of Embodiments of the Present Disclosure] Specific examples of wire harnesses, detection systems, and detection methods according to embodiments of the present disclosure will be described below with reference to the drawings. Note that in the following embodiments, identical components are assigned the same reference numerals. Their functions and names are also identical. Therefore, detailed description thereof will not be repeated.

[0031] 1 , a wire harness 100 according to this embodiment is a wire harness used for communication between on-vehicle devices. The on-vehicle devices include a first on-vehicle device 60 and a second on-vehicle device 70. The first on-vehicle device 60 includes a first communication unit 62, and the second on-vehicle device 70 includes a second communication unit 72. The wire harness 100 connects the first communication unit 62 and the second communication unit 72 for communication.

[0032] In the present embodiment, the wire harness 100 is directly connected to the first in-vehicle device 60 and the second in-vehicle device 70. However, the wire harness 100 may be configured to be indirectly connected to the first in-vehicle device 60 or the second in-vehicle device 70 via another wire harness or the like.

[0033] Assume that the first in-vehicle device 60 and the second in-vehicle device 70 are both ECUs. In this case, the first communication unit 62 and the second communication unit 72 include a PHY (Physical Layer). The PHY is configured by a chip (integrated circuit) mounted on the ECU that transmits and receives signals.

[0034] The first in-vehicle device 60 includes a board 64 on which a first communication unit 62 is mounted, and a connector 66. The connector 66 and the first communication unit 62 are electrically connected by a wiring unit (not shown). The second in-vehicle device 70 includes a board 74 on which a second communication unit 72 is mounted, and a connector 76. The connector 76 and the second communication unit 72 are electrically connected by a wiring unit (not shown).

[0035] The wire harness 100 includes a first connector 102, a second connector 104, and a cable 110 arranged between the first connector 102 and the second connector 104. The first connector 102 is connected to a first end of the cable 110, and the second connector 104 is connected to a second end of the cable 110. The first connector 102 is connected to a connector 66 of a first in-vehicle device 60, and the second connector 104 is connected to a connector 76 of a second in-vehicle device 70. When the cable 110 is extended linearly, the extension direction of the cable 110 is defined as direction L1.

[0036] Referring to Fig. 2, the cable 110 of the wire harness 100 has a configuration in which a plurality of electric wires are bundled together by an insulating exterior material 112. The exterior material 112 is, for example, an insulating coating that covers the plurality of electric wires. The plurality of electric wires may include an electric wire that transmits highly confidential information. Such an electric wire needs to be protected against unauthorized access, and therefore may be referred to as a "protected electric wire" hereinafter. Here, a specific electric wire included in the plurality of electric wires is referred to as a protected electric wire 120.

[0037] A conductor 114 that functions as an electrical ground is inserted inside the exterior material 112. Specifically, the conductor 114 is made of a conductive material such as a metal material, and covers a plurality of electric wires. The exterior material 112 covers the plurality of electric wires via the conductor 114.

[0038] The multiple electric wires include a detection electric wire 130. The detection electric wire 130 is an electric wire without a shield. The conductor 114 functions as a ground for the detection electric wire 130. The detection electric wire 130 is arranged (designed) so that its impedance (characteristic impedance) is a predetermined value (hereinafter sometimes referred to as a "prescribed value") by adjusting the positional relationship between the detection electric wire 130 and the conductor 114 and the material of the member arranged between the detection electric wire 130 and the conductor 114. The predetermined value may be, for example, 50±10 Ω. The predetermined value is not limited to this and may be a value other than this.

[0039] 3 , the detection wire 130 includes a conductive core wire 132 and an insulating coating 134 that covers the core wire 132. The impedance of the detection wire 130 may be adjusted by adjusting the thickness of the insulating coating 134 (thickness of the coating material) or by changing the material of the insulating coating 134.

[0040] 4, the electric wire 120 to be protected is an electric wire having a shield. The electric wire 120 to be protected includes a core wire 122, a dielectric 124 covering the core wire 122, a metal shield 126 disposed on the outside of the dielectric 124, and an insulating coating 128 covering the metal shield 126. The impedance (characteristic impedance) of the electric wire 120 to be protected is, for example, 50 Ω. The other electric wires except for the detection wire 130 have the same configuration as the electric wire 120 to be protected. The multiple electric wires including the electric wire 120 to be protected may be electric wires without a shield.

[0041] [Communication System 50] Referring again to FIG. 1 , the communication system 50 according to the present embodiment includes the wire harness 100 described above and a detection device 150 electrically connected to the wire harness 100. The detection device 150 detects that probing or the like is being performed by monitoring a change in impedance of the detection wire 130. In the present embodiment, the first in-vehicle device 60 includes the detection device 150. That is, the first in-vehicle device 60 also functions as the detection device 150. The detection device 150 may be included in the second in-vehicle device 70, or may be included in both the first in-vehicle device 60 and the second in-vehicle device 70. The detection device 150 may be mounted on an in-vehicle device that stores highly confidential information.

[0042] Referring to FIG. 5 , the first in-vehicle device 60 further includes a control unit 80 and a storage unit 82 in addition to the first communication unit 62. The control unit 80 includes a computing element (processor) such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The storage unit 82 includes a non-volatile memory such as a flash memory. The storage unit 82 stores software (computer programs) executed by the control unit 80 and various information (data). The functions of each functional unit of the first in-vehicle device 60 are realized by software processing executed by the control unit 80 using hardware. The first in-vehicle device 60 also functions as a detection device 150. Some or all of these functions may be realized by an integrated circuit including a microcomputer.

[0043] 6 , the detection device 150 includes, as functional units, an impedance monitoring unit 152 that monitors changes in the impedance of the detection wire 130 (see FIG. 2 ) and a communication limiting unit 158 ​​that limits communication via the wire harness 100 in accordance with the monitoring results of the impedance monitoring unit 152. The impedance monitoring unit 152 includes a measuring unit 154 that measures the impedance of the detection wire 130 and a determining unit 156 that determines whether unauthorized communication is occurring based on the impedance measurement results by the measuring unit 154. The determining unit 156 determines that unauthorized communication is occurring in response to a change in the impedance of the detection wire 130 that is equal to or greater than a predetermined threshold. The predetermined threshold is set in advance and stored in the memory unit 82 (see FIG. 5 ). The determining unit 156 makes the determination by appropriately referring to the threshold stored in the memory unit 82.

[0044] The communication restriction unit 158 ​​restricts communication when it is determined that unauthorized communication is occurring. Specifically, the communication restriction unit 158 ​​blocks communication when it is determined that unauthorized communication is occurring. However, instead of blocking all communication, some communication may be allowed to continue. For example, communication of low-confidentiality information via electric wires other than the electric wire 120 to be protected may be allowed to continue.

[0045] Some ECUs, a type of in-vehicle device, have an impedance measurement function that uses TDR (Time Domain Reflectometry). TDR is a method of measuring changes in the characteristic impedance (discontinuities) of an electric wire by transmitting a pulse signal or step signal to the object being measured and observing the reflected waveform.

[0046] If the first in-vehicle device 60 is an ECU having such a function, the detection device 150 may monitor the change in impedance of the detection wire 130 using the impedance measurement function using a TDR.

[0047] The second in-vehicle device 70 may have the same configuration as the first in-vehicle device 60. However, the second in-vehicle device 70 may be configured to include a detection device or may not include a detection device.

[0048] 7, the detection device 150 of the first in-vehicle device 60 is electrically connected to the detection wire 130. The measurement unit 154 (see FIG. 6) of the detection device 150 measures the characteristic impedance of the detection wire 130 by, for example, the TDR method.

[0049] During probing, which involves unauthorized access or other attempts to steal information, the outer casing 112 and the conductor 114 are stripped away. Because the conductor 114 functions as a ground for the detection wire 130, stripping the conductor 114 changes the impedance of the detection wire 130. More specifically, when the outer casing 112 and the conductor 114 of the cable 110 are partially stripped away for probing, the impedance of the detection wire 130 at the stripped portion significantly deviates from the specified value. If the impedance of the detection wire 130 deviates by more than a threshold value, probing may be attempted. Therefore, when the impedance monitoring unit 152 (see FIG. 6 ) of the detection device 150 detects such a change in impedance, it determines that unauthorized communication is occurring. If the detection device 150 determines that unauthorized communication is occurring, it restricts the communication.

[0050] As described above, the wire harness 100 or the communication system 50 according to the present embodiment can detect signs of unauthorized access such as probing in advance, thereby improving communication security. In addition, since communication security can be improved without using a member such as a protective cover that is easily visible from the outside, it is possible to make it difficult to tell from the outside whether or not security measures have been taken.

[0051] The multiple electric wires included in the cable 110 include a communication electric wire (the electric wire 120 to be protected) that is different from the detection electric wire 130. By providing the detection electric wire 130 separately from the electric wire 120 to be protected, it is easy to arrange the detection electric wire 130 so that its impedance becomes a predetermined value (prescribed value). This makes it possible to easily improve communication security.

[0052] By using a shielded electric wire as the electric wire 120 to be protected, deterioration of communication performance can be suppressed.

[0053] (Modification) In the above embodiment, the detection wire 130 may be arranged (designed) so that the impedance of the detection wire 130 becomes a specified value by inserting another dielectric between the detection wire 130 and the conductor 114. An example of such a configuration will be described below.

[0054] 8 , in a cable 110A according to a modified example, a dielectric 116 is disposed between a conductor 114 and a detection wire 130. The dielectric 116 is, for example, an insulating coating having a predetermined thickness, and covers a plurality of wires including the detection wire 130 and the electric wire 120 to be protected. The conductor 114 is disposed between the exterior material 112 and the dielectric 116. By adjusting the thickness or material of the dielectric 116, the impedance of the detection wire 130 is set to a specified value.

[0055] The dielectric inserted between the detection wire 130 and the conductor 114 may be a dielectric other than the insulating coating. For example, the dielectric may be configured to be partially inserted between the detection wire 130 and the conductor 114.

[0056] The other configurations are the same as those of the first embodiment.

[0057] Second Embodiment Referring to FIG. 9 , a wire harness 200 according to this embodiment differs from the first embodiment in that the electric wire 220 to be protected also serves as the detection electric wire. Therefore, the electric wire 220 to be protected is an electric wire without a shield. The conductor 114 functions as a ground for the electric wire 220 to be protected, which also serves as the detection electric wire. Because the electric wire 220 to be protected is also the detection electric wire, the electric wire 220 is arranged (designed) so that its impedance (characteristic impedance) is a predetermined value (specified value) by adjusting the positional relationship between the electric wire 220 and the conductor 114 and the materials of the members arranged between the electric wire 220 and the conductor 114. The predetermined value may be, for example, 50±10 Ω, as described above.

[0058] Referring to FIG. 10, an electric wire (detection wire) 220 to be protected includes a conductive core wire 222 and an insulating coating 224 that covers the core wire 222 .

[0059] This configuration eliminates the need for a separate detection wire, which reduces the amount of cable used, and as a result, even when improving communication security, it is possible to suppress increases in the cost of wire harnesses.

[0060] The other configurations and effects are the same as those of the first embodiment.

[0061] Third Embodiment Referring to FIG. 11, a communication system 50A according to the present embodiment differs from the first and second embodiments in that a wire harness 300 is included instead of wire harness 100 (see FIG. 1).

[0062] The wire harness 300 includes a first connector 302, a second connector 304, and a cable 310 arranged between the first connector 302 and the second connector 304. The first connector 302 is connected to a first end of the cable 310, and the second connector 304 is connected to a second end of the cable 310. The cable 310 is a flat cable. When the cable 310 is extended linearly, the extension direction of the cable 310 is defined as direction L2.

[0063] 12 , cable 310 of wire harness 300 has a laminated structure in which a plurality of electric wires are arranged in a plurality of layers. An example of a laminated structure having four layers is shown in Fig. 12 . However, the number of layers in the laminated structure is not limited to four, and may be two, three, five or more.

[0064] The multiple electric wires include an electric wire 320 to be protected and a detection electric wire 330. The electric wire 320 to be protected has a configuration similar to that of the electric wire 120 to be protected (see FIG. 4) shown in the first embodiment. The detection electric wire 330 is an electric wire without a shield, and has a configuration similar to that of the detection electric wire 130 (see FIG. 3) shown in the first embodiment.

[0065] The multiple electric wires are held by a sheet-shaped holding member. The holding member includes a first sheet 340, a second sheet 342, and a third sheet 344, which are all flexible insulating sheets. The first sheet 340, the second sheet 342, and the third sheet 344 are formed to, for example, the same size. The holding member further includes a sheet-shaped conductor 350. The sheet-shaped conductor 350 includes a first conductor sheet 352 and a second conductor sheet 354. The first conductor sheet 352 and the second conductor sheet 354 are formed to, for example, the same size as the first sheet 340, the second sheet 342, and the third sheet 344. The first sheet 340 and the third sheet 344 function as exterior materials.

[0066] The electric wires in each layer are sandwiched between two sheet-like holding members and fixed to the upper and lower holding members. The electric wires may be fixed to the holding members by, for example, ultrasonic welding or laser welding, or by adhesive.

[0067] The detection wire 330 is arranged on the same layer as the electric wire 320 to be protected. The detection wire 330 and the electric wire 320 to be protected are sandwiched between the first conductor sheet 352 and the second conductor sheet 354. That is, the detection wire 330 and the electric wire 320 to be protected are arranged between the first conductor sheet 352 and the second conductor sheet 354. More specifically, the detection wire 330 is fixed to the first conductor sheet 352 and the second conductor sheet 354. As in the first embodiment, the characteristic impedance of the detection wire 330 is adjusted to a predetermined value (specified value) by appropriately changing the thickness or material of the dielectric arranged between the first conductor sheet 352 and the second conductor sheet 354.

[0068] 13, the detection device 150 of the first in-vehicle device 60 is electrically connected to the detection wire 330. The measurement unit 154 (see FIG. 6) of the detection device 150 measures the characteristic impedance of the detection wire 330 by, for example, the TDR method.

[0069] 12 , when probing for the purpose of stealing information, such as unauthorized access, the sheets are peeled off first. Since the electric wire 320 to be protected is arranged on the same layer as the detection electric wire 330, when probing from the top side of the cable 310, the first sheet 340, the second sheet 342, and the first conductor sheet 352 are peeled off. On the other hand, when probing from the bottom side of the cable 310, the third sheet 344 and the second conductor sheet 354 are peeled off. In either case, the sheet-like conductor 350 is peeled off together with the outer covering.

[0070] Because the sheet-like conductor 350 functions as a ground for the detection wire 330, peeling off the conductor 350 changes the impedance of the detection wire 330. If the impedance of the detection wire 330 deviates by more than a threshold value, probing may be attempted. When the impedance monitor 152 (see FIG. 6 ) of the detection device 150 detects such a change in impedance, it determines that unauthorized communication is occurring. If the detection device 150 determines that unauthorized communication is occurring, it restricts the communication.

[0071] A flat wire harness has the advantage that it can have various functions such as sound deadening, sound absorption, abrasion resistance, heat dissipation, shielding, and waterproofing depending on the function of the exterior material (holding member). However, it has the disadvantage that the sheet-like exterior material is easily peeled off, making it easy to peel off the sheet for probing.

[0072] The wire harness 300 of this embodiment and the communication system 50A equipped with the wire harness 300 can detect signs of unauthorized access such as probing in advance, thereby preventing unauthorized access through probing while enjoying the advantages of conventional wire harnesses.

[0073] The flat cable 310 can easily fix the positional relationship between the conductor 350, which functions as the ground, and the detection wire 330, thereby more stabilizing the impedance of the detection wire 330. This makes it easier to detect changes in impedance, thereby improving the accuracy of detecting unauthorized access.

[0074] Furthermore, by using the sheet-like conductor 350 as the conductor, it is necessary to peel off the sheet-like conductor 350 to expose the protected electric wire 320 during probing. In this way, by configuring the conductor 350 to be peeled off inevitably during probing, it is possible to easily change the impedance of the detection electric wire 330. This can further improve the accuracy of detecting unauthorized access.

[0075] Furthermore, by disposing the detection wire 330 between the first conductor sheet 352 and the second conductor sheet 354, the sheet-like conductor 350 is peeled off when probing is performed from either the top or bottom side of the flat cable 310. This allows the impedance change of the detection wire 330 to be detected effectively, thereby further improving communication security.

[0076] The other configurations and effects are the same as those of the first embodiment.

[0077] 14 , a communication system 50B according to the present embodiment differs from the third embodiment in that a wire harness 400 is included instead of the wire harness 300 (see FIG. 11 ). The wire harness 400 includes a cable 410 instead of the cable 310 (see FIG. 11 ).

[0078] 15 , similarly to the third embodiment, cable 410 of wire harness 400 is a flat cable having a laminated structure in which a plurality of electric wires are arranged in a plurality of layers. The plurality of electric wires includes electric wire 320 to be protected and electric wire 330 for detection. The plurality of electric wires are held by a sheet-like holding member.

[0079] The holding member includes a first sheet 420, a second sheet 422, a third sheet 424, and a fourth sheet 426, which are all flexible insulating sheets. The first sheet 420 and the fourth sheet 426 function as exterior materials. The holding member further includes a sheet-like conductor 350. The sheet-like conductor 350 includes a first conductor sheet 352 and a second conductor sheet 354.

[0080] In this embodiment, the detection wire 330 is arranged on the outermost layer in the laminated structure. The arrangement of the electric wire 320 to be protected is arbitrary. Here, the electric wire 320 to be protected is arranged on a different layer from the detection wire 330. However, the electric wire 320 to be protected may also be configured to be arranged on the same layer as the detection wire 330. The detection wire 330 is arranged between the first conductor sheet 352 and the second conductor sheet 354.

[0081] When probing is performed with the aim of stealing information, such as through unauthorized access, the sheets are peeled off first. At this time, the sheets are peeled off starting from the outermost sheet up to the layer on which the electric wire 320 to be protected is arranged. Therefore, by arranging the detection electric wire 330 on the outermost layer, the conductor 350 (352) of the layer on which the detection electric wire 330 is arranged is peeled off first. This makes it easier to detect signs of unauthorized access, such as probing.

[0082] Furthermore, with this configuration, it is possible to detect the execution of probing without placing the electric wire 320 to be protected on the same layer as the detection electric wire 330, thereby reducing wiring restrictions on other electric wires including the electric wire 320 to be protected. Therefore, for example, the electric wire 320 to be protected can be placed on a different layer from the detection electric wire 330.

[0083] The other configurations and effects are the same as those of the third embodiment.

[0084] In the above embodiment, a flexible insulating sheet may be used in place of second conductor sheet 354. Furthermore, a sheet-like conductor may be used in place of second sheet 422. Similarly, a sheet-like conductor may be used in place of third sheet 424.

[0085] 16 , a communication system 50C according to the present embodiment differs from the third embodiment in that a wire harness 500 is included instead of the wire harness 300 (see FIG. 11 ). The wire harness 500 includes a cable 510 instead of the cable 310 (see FIG. 11 ).

[0086] The cable 510 of the wire harness 500 is a flat cable similar to that of the third embodiment, and has a laminated structure in which a plurality of electric wires are arranged in a plurality of layers. The plurality of electric wires includes electric wires to be protected and electric wires for detection. The plurality of electric wires are held by a sheet-like holding member.

[0087] 17 , the holding member includes a first sheet 520 and a second sheet 522, both of which are flexible insulating sheets. The first sheet 520 and the second sheet 522 function as exterior materials. The holding member further includes a sheet-like conductor 530. The sheet-like conductor 530 includes a first conductor sheet 532, a second conductor sheet 534, a third conductor sheet 536, a fourth conductor sheet 538, and a fifth conductor sheet 540. The second conductor sheet 534, the third conductor sheet 536, and the fourth conductor sheet 538 have through holes formed therein through which the detection wire 550 is inserted. The detection wire 550 is an electric wire without a shield and has a configuration similar to that of the detection wire 130 (see FIG. 3 ) shown in the first embodiment.

[0088] The detection wire 550 is arranged across layers via through holes formed in the second conductor sheet 534, the third conductor sheet 536, and the fourth conductor sheet 538. As a result, the detection wire 550 is arranged on multiple layers, and the impedance of the detection wire 550 changes when the conductor of any layer in the laminated structure is peeled off. This makes it easy to configure the detection wire 550 so that its impedance changes during probing. Therefore, this configuration can further improve communication security.

[0089] The other configurations and effects are the same as those of the third or fourth embodiment.

[0090] (Modification) In the above embodiment, an example of a wire harness including one detection wire has been described. However, the present disclosure is not limited to such an embodiment. The wire harness may include a plurality of detection wires. In this case, a plurality of detection devices may be provided corresponding to the plurality of detection wires.

[0091] In the above embodiment, an example has been described in which the characteristic impedance of the detection wire is set to be approximately the same as that of the wire to be protected. However, the present disclosure is not limited to such an embodiment. The characteristic impedance of the detection wire may be set to a value (prescribed value) different from the characteristic impedance of other wires, such as the wire to be protected. For example, if the characteristic impedance of the other wires is 50 Ω, the characteristic impedance of the detection wire may be set to, for example, approximately 35 Ω to 40 Ω. This increases the degree of freedom in setting the impedance of the detection wire, making it easier to improve communication security.

[0092] In the above embodiment, an example has been described in which it is determined that unauthorized communication is occurring when the characteristic impedance of the detection wire changes by a predetermined threshold or more. However, the present disclosure is not limited to such an embodiment. For example, it may be determined that unauthorized communication is occurring when the difference between the characteristic impedance of the detection wire and the characteristic impedance of another wire having a shield increases by a predetermined value or more. Furthermore, it may be determined that unauthorized communication is occurring when the range of fluctuation in the characteristic impedance of the detection wire from its history increases by a predetermined value or more.

[0093] In the above embodiment, an example in which the characteristic impedance of the detection wire is measured using the TDR method has been described. However, the present disclosure is not limited to such an embodiment. The characteristic impedance of the detection wire may be measured using a method other than the TDR method.

[0094] In the above embodiment, an example has been shown in which the electric wires in the wire harness other than the detection electric wire are shielded. However, the present disclosure is not limited to such an embodiment. The electric wires other than the detection electric wire may be shielded or may not be shielded.

[0095] In the above embodiment, an example has been shown in which the flat wire harness has a laminated structure in which a plurality of layers are laminated. However, the present disclosure is not limited to such an embodiment. The flat wire harness may have a single-layer structure.

[0096] In the above embodiment, an example of a flat wire harness configured such that a detection wire is sandwiched between two conductive sheets is shown. However, the present disclosure is not limited to such an embodiment. In the flat wire harness, the conductive sheet may be provided only on one side of the detection wire.

[0097] Embodiments obtained by appropriately combining the techniques disclosed above are also included within the technical scope of the present disclosure.

[0098] The embodiments disclosed herein are merely examples, and the present disclosure is not limited to the above-described embodiments. The scope of the present disclosure is defined by the claims in the scope of the claims, taking into consideration the description of the detailed description of the invention, and includes all modifications within the meaning and scope equivalent to the wording described therein.

[0099] 50, 50A, 50B, 50C Communication system 60 First in-vehicle device 62 First communication unit 64, 74 Board 66, 76 Connector 70 Second in-vehicle device 72 Second communication unit 80 Control unit 82 Memory unit 100, 200, 300, 400, 500 Wire harness 102, 302 First connector 104, 304 Second connector 110, 110A, 310, 410, 510 Cable 112 Sheathing material 114 Conductor 116, 124 Dielectric 120, 220, 320 Electric wire to be protected 122, 132, 222 Core wire 126 Metal shield 128, 134, 224 Insulating coating 130, 330, 550 Detection wire 150 Detection device 152 Impedance monitoring unit 154 Measuring unit 156 Determination unit 158 ​​Communication restriction unit 340, 420, 520 First sheet 342, 422, 522 Second sheet 344, 424 Third sheet 350, 530 Sheet-shaped conductor 352, 532 First conductor sheet 354, 534 Second conductor sheet 426 Fourth sheet 536 Third conductor sheet 538 Fourth conductor sheet 540 Fifth conductor sheet

Claims

1. A wire harness that connects communication between a first communication unit and a second communication unit, a first connector and a second connector; a cable disposed between the first connector and the second connector, The cable a plurality of wires including a detection wire; a conductor that functions as a ground for the detection wire; The detection wire is an unshielded wire, and is arranged so that the impedance of the detection wire is a predetermined value.

2. The wire harness according to claim 1 , wherein the plurality of electric wires includes a communication electric wire different from the detection electric wire.

3. The wire harness according to claim 2 , wherein the communication wire has a shield.

4. 4. The wire harness according to claim 2, wherein an impedance of the detection wire is different from an impedance of the communication wire.

5. the plurality of electric wires includes communication wires, The wire harness according to claim 1 , wherein the communication wire includes the detection wire.

6. The wire harness according to claim 1 , wherein the cable is flat.

7. The wire harness according to claim 6 , wherein the conductor includes a sheet-like conductor.

8. the sheet-like conductor includes a first conductor sheet and a second conductor sheet, The wire harness according to claim 7 , wherein the detection wire is disposed between the first conductive sheet and the second conductive sheet.

9. 7. The wire harness according to claim 6, wherein when a specific electric wire included in the plurality of electric wires is a wire to be protected, the detection electric wire is arranged in the same layer as the layer in which the electric wire to be protected is arranged.

10. The cable has a laminated structure in which the plurality of electric wires are arranged in a plurality of layers, The wire harness according to claim 6, wherein the detection wire is disposed in an outermost layer of the laminated structure.

11. The cable has a laminated structure in which the plurality of electric wires are arranged in a plurality of layers, The wire harness according to claim 6 , wherein the detection wire is arranged across layers.

12. A wire harness, a detection device electrically connected to the wire harness, The wire harness includes: a first connector and a second connector; a cable disposed between the first connector and the second connector, The cable a plurality of wires including a detection wire; a conductor that functions as a ground for the detection wire; the detection wire is an unshielded wire and is arranged so that the impedance of the detection wire is a predetermined value; The detection device is a measuring unit for measuring the impedance of the detection wire; a determination unit that determines whether or not unauthorized communication is occurring based on the impedance measurement result by the measurement unit.

13. The detection system according to claim 12 , wherein the determination unit determines that unauthorized communication is occurring in response to a change in impedance of the detection wire that is equal to or greater than a predetermined threshold value.

14. A detection method for detecting unauthorized communication in communication via a wire harness, comprising: the cable of the wire harness includes a plurality of electric wires including a detection electric wire and a conductor that functions as a ground for the detection electric wires, the detection electric wires being electric wires that do not have a shield and are arranged so that the impedance of the detection electric wires is a predetermined value; The detection method measures the impedance of a detection wire and determines whether or not unauthorized communication is taking place based on the measurement result.

15. 15. The detection method according to claim 14, wherein the detection method determines that unauthorized communication is occurring in response to a change in impedance of the detection wire that is equal to or greater than a predetermined threshold value.