Security system

Abstract

This security system is used in a system in which communication between a first communication unit and a second communication unit is connected by means of a communication line. The security system includes: a signal modification unit that modifies the signal waveform of a communication signal to be transmitted in communication; and a signal correction unit that corrects the signal waveform modified by the signal modification unit.

Description

Security Systems

[0001] This disclosure relates to a security system, a wire harness, a connector, and an in-vehicle device. This application claims priority to Japanese Patent Application No. 2023-105866, filed on June 28, 2023, and incorporates by reference all of the contents of said Japanese application.

[0002] Vehicles are equipped with various on-board devices. These 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." Wiring harnesses are usually used to connect the 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 a connector system for preventing communication between a wire harness and unintended devices.

[0004] The connector system described in Patent Document 1 includes a first connector and a second connector connected thereto. The second connector includes a processing unit that creates verification information and transmits it to the first connector. The first connector includes a verification unit that verifies the second connector based on the verification information received from the second connector. The verification unit determines that verification has failed if it is unable to receive the verification information. The first connector further includes a switch that, when connected to the second connector, switches between electrically connecting the transmission line in the first connector and the transmission line in the second connector, and a control unit that controls the switch based on the verification results of the verification unit.

[0005] If the second connector is an unauthorized connector, the verification unit of the first connector determines that the verification has failed. The control unit of the first connector maintains the switch in the off state. This interrupts the electrical connection between the transmission line of the first connector and the transmission line of the second connector. This prevents communication between the wire harness and unintended devices, ensuring the security of communication between devices.

[0006] International Publication No. 2019 / 187349

[0007] A security system according to one aspect of the present disclosure is a security system used in a system that connects communication between a first communication unit and a second communication unit via a communication line, and includes a signal transformation unit that transforms the signal waveform of a communication signal transmitted in the communication, and a signal correction unit that corrects the signal waveform transformed by the signal transformation unit.

[0008] The present disclosure can be realized not only as a security system, wire harness, connector, or in-vehicle device that includes such a characteristic configuration, but also as other systems or devices that include a security system, wire harness, connector, or in-vehicle device.

[0009] FIG. 1 is a diagram illustrating a security system according to a first embodiment. FIG. 2 is a diagram illustrating an example of a signal filter unit (low-pass filter). FIG. 3 is a diagram illustrating an example of frequency characteristics of a low-pass filter. FIG. 4 is a diagram illustrating an example of a signal filter unit (open stub filter). FIG. 5 is a diagram illustrating an example of frequency characteristics of an open stub filter. FIG. 6 is a diagram illustrating changes in the signal waveform of a communication signal in the security system shown in FIG. 1. FIG. 7 is a diagram illustrating an example of the configuration of the security system shown in FIG. 1. FIG. 8 is a diagram illustrating an example of the configuration of a connector of the wire harness shown in FIG. 7. FIG. 9 is a diagram illustrating an example of a signal waveform of a received signal in the case of overcorrection. FIG. 10 is a diagram illustrating an example of a signal waveform of a received signal in the case of undercorrection. FIG. 11 is a diagram illustrating an example of the configuration of a wire harness according to a second embodiment. FIG. 12 is a diagram illustrating a security system according to a third embodiment. FIG. 13 is a diagram illustrating changes in the signal waveform of a communication signal in the security system shown in FIG. 12. FIG. 14 is a diagram illustrating an example of the configuration of the security system shown in FIG. 12. FIG. 15 is a diagram illustrating an example of the configuration of a connector of the wire harness shown in FIG. 14. Fig. 16 is a diagram showing an example of a signal waveform of a received signal in the case of insufficient correction. Fig. 17 is a diagram showing an example of a signal waveform of a received signal in the case of overcorrection. Fig. 18 is a diagram for explaining an in-vehicle device according to a fourth embodiment. Fig. 19 is a diagram showing an example of the configuration of the in-vehicle device shown in Fig. 18. Fig. 20 is a diagram showing an example of the configuration of an in-vehicle device according to a modified example. Fig. 21 is a diagram for explaining an in-vehicle device according to a fifth embodiment.

[0010] The connector system described in Patent Document 1 is an excellent system in terms of ensuring security. However, because the processing unit, verification unit, and control unit are realized by electronic devices, and the electronic devices and switches are built into the connector, it is difficult to simplify the configuration. As a result, manufacturing costs tend to be high.

[0011] The present disclosure has been made to solve such problems, and one object of the present disclosure is to provide a security system, a wire harness, a connector, and an on-board device that can improve communication security with a simpler configuration.

[0012] Effect of the Present Disclosure According to the present disclosure, it is possible to provide a security system, a wire harness, a connector, and an in-vehicle device that can improve communication security with a simpler configuration.

[0013] [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.

[0014] (1) A security system according to a first aspect of the present disclosure is a security system used in a system that connects communication between a first communication unit and a second communication unit via a communication line, and includes a signal modification unit that modifies the signal waveform of a communication signal transmitted in the communication, and a signal correction unit that corrects the signal waveform modified by the signal modification unit.

[0015] The signal modification unit modifies the signal waveform of a communication signal transmitted during communication. The signal correction unit corrects the modified signal waveform. When the system includes the signal modification unit and the signal correction unit, communication between the first communication unit and the second communication unit is performed normally. On the other hand, when an unauthorized device is connected to the first communication unit or the second communication unit, either the signal modification unit or the signal correction unit is not present. For example, when the signal modification unit is present but the signal correction unit is not, the signal waveform of the communication signal is not corrected. Furthermore, when the signal modification unit is not present but the signal correction unit is present, the signal waveform of the communication signal is overcorrected. In either case, signal quality deteriorates, thereby suppressing normal communication with unauthorized devices. Furthermore, the signal modification unit and the signal correction unit can be easily simplified in configuration. Therefore, this security system can improve communication security with a simpler configuration.

[0016] (2) In the above (1), the signal transforming unit may include a signal filter unit that filters a communication signal that is a signal within a communication band used for communication, and the signal correcting unit may include a signal waveform correcting circuit that corrects the signal waveform transformed by the signal filter unit. This allows for an easier and simpler configuration.

[0017] (3) In the above (2), the signal filter unit may filter the communication signal transmitted by the first communication unit, and the second communication unit may include a signal waveform correction circuit. This makes it easy to implement the signal waveform correction circuit, and therefore, it is possible to easily achieve a configuration including the signal waveform correction circuit.

[0018] (4) In the above (1), the signal modifying unit may include a signal waveform modifying circuit that modifies the signal waveform of the communication signal, and the signal correcting unit may include a signal filter that filters the signal waveform modified by the signal waveform modifying circuit. This allows for an easier and simpler configuration.

[0019] (5) In the above (4), the first communication unit may include a signal waveform modification circuit that modifies the waveform of a communication signal transmitted by the first communication unit, and the signal filter unit may be provided on a transmission line leading to reception of the communication signal by the second communication unit. This facilitates implementation of the signal waveform modification circuit, and therefore makes it easy to achieve a configuration that includes the signal waveform modification circuit.

[0020] (6) In any of the above (2) to (5), the signal filter unit may include a low-pass filter or a band-reject filter. This makes it possible to easily form the signal filter unit.

[0021] (7) In any of the above (2) to (6), the communication between the first communication unit and the second communication unit may be connected by a wire harness, the wire harness may include a communication line and a connector connected to an end of the communication line, and the signal filter unit may be provided on the communication line or the connector. This also makes it possible to easily achieve a simpler configuration.

[0022] (8) In the above (7), the wire harness may further include a sheet-like holding member for holding the communication wires. This makes it possible to obtain a flat wire harness that can improve communication security with a simpler configuration.

[0023] (9) In any of the above (2) to (6), the signal filter unit may be provided on at least one of the first electrical board on which the first communication unit is mounted, a connector provided on the first electrical board, the second electrical board on which the second communication unit is mounted, and a connector provided on the second electrical board. This also facilitates a simpler configuration.

[0024] (10) A wire harness according to a second aspect of the present disclosure is a wire harness that connects communication between a first communication unit and a second communication unit, and includes a communication line, a connector that is connected to an end of the communication line, and a signal filter unit that is provided on the communication line or the connector and filters a communication signal transmitted in the communication.

[0025] The signal filter unit can correct the signal waveform deformation when the signal waveform of the communication signal is deformed, and can deform the signal waveform of the communication signal when the signal waveform of the communication signal is not deformed. For example, if the signal waveform of a communication signal transmitted in communication is deformed, the signal waveform deformation can be corrected by using this wire harness. Furthermore, for example, if the first communication unit and the second communication unit have a function to correct the signal waveform deformation, even if the signal waveform is deformed by the signal filter unit, the first communication unit and the second communication unit can receive the communication signal by correcting the signal waveform deformation. Therefore, with this configuration, communication between the first communication unit and the second communication unit is performed normally.

[0026] On the other hand, if an unauthorized device is connected to the first communication unit or the second communication unit, the unauthorized device will receive a communication signal that has been deformed by the signal filter unit of the wire harness. Even if the wire harness is removed and an unauthorized device is connected to the first communication unit or the second communication unit, if the signal waveform of the communication signal has been deformed, the unauthorized device will receive the deformed communication signal. Therefore, in such cases, normal communication with the unauthorized device can be suppressed. Therefore, by using this wire harness, communication security can be improved with a simpler configuration.

[0027] (11) In the above (10), the signal filter section may include a low-pass filter or a band-reject filter, which makes it possible to easily form the signal filter section.

[0028] (12) In the above (10) or (11), a sheet-like holding member for holding the communication wires may be further included. This makes it possible to obtain a flat wire harness that can improve communication security with a simpler configuration.

[0029] (13) A connector according to a third aspect of the present disclosure is a connector used in a system that connects communication between a first communication unit and a second communication unit via a communication line, and includes a housing and a signal filter unit that is provided within the housing and filters communication signals transmitted in the communication.

[0030] By using this connector, communication security can be improved with a simpler configuration.

[0031] (14) A fourth aspect of the present disclosure provides an in-vehicle device that communicates with other in-vehicle devices via a communication line, and includes a communication unit that communicates with the other in-vehicle devices. The communication unit includes a signal waveform correction circuit that corrects deformation of the signal waveform when the signal waveform of a communication signal transmitted from the other in-vehicle device is deformed.

[0032] According to this in-vehicle device, communication security can be improved with a simpler configuration.

[0033] (15) In the above (14), a signal filter unit may be further included that filters a signal to be transmitted to another vehicle-mounted device in order to modify the signal waveform. This can further improve communication security.

[0034] (16) A fifth aspect of the present disclosure provides an in-vehicle device that communicates with other in-vehicle devices via a communication line, and includes a communication unit that communicates with the other in-vehicle devices, and the communication unit includes a signal waveform modification circuit that modifies the signal waveform of a transmission signal to be transmitted to the other in-vehicle devices.

[0035] This in-vehicle device also improves communication security with a simpler configuration.

[0036] (17) In the above (16), a signal filter unit may be further included that, when the signal waveform of a communication signal transmitted from another in-vehicle device is deformed, filters the signal waveform to correct the deformation. This can further improve communication security.

[0037] [Details of the Embodiments of the Present Disclosure] Specific examples of a security system, a wire harness, a connector, or an in-vehicle device according to the 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.

[0038] 1, a security system 50 according to this embodiment is used in a system in which communication between in-vehicle devices (e.g., communication between ECU1 and ECU2) is connected via a communication line 20 (transmission line). This security system 50 includes a signal modification unit 100 that modifies the signal waveform of a communication signal transmitted in the communication, and a signal correction unit 120 that corrects the signal waveform modified by the signal modification unit 100.

[0039] In this disclosure, the term "communication band" refers to a frequency band used for communication between devices, and is a band that satisfies the frequency characteristics of a standard such as IEEE 802.3 (registered trademark).

[0040] The signal transforming unit 100 includes a signal filtering unit 102. The signal filtering unit 102 filters the communication signal, which is a signal within the communication band used for communication.

[0041] The signal filter unit 102 includes a signal distortion filter 104. That is, in the present security system 50, the signal filter unit 102 is used as the signal distortion filter 104. The signal distortion filter 104 is provided on a transmission line for communication between the ECU 1 and the ECU 2. The signal waveforms of the transmission signals from the ECU 1 and the ECU 2 are deformed by the signal distortion filter 104.

[0042] The signal correction unit 120 includes a signal waveform correction circuit 122 that corrects the signal waveform deformed by the signal filter unit 102 (signal distortion filter 104). The signal waveform correction circuit 122 includes a signal waveform correction circuit 122a provided in ECU1 and a signal waveform correction circuit 122b provided in ECU2. The signal waveform correction circuits 122a and 122b are collectively referred to as the "signal waveform correction circuit 122." The signal waveform correction circuit 122 may be provided in only one of ECU1 and ECU2. Here, an example will be described in which the signal waveform correction circuit 122 is provided in both ECU1 and ECU2.

[0043] The ECU 1 further includes amplifiers 130 and 132 as input / output buffers. The ECU 1 transmits a transmission signal (communication signal) to the ECU 2 via the amplifier 130, and receives the transmission signal (communication signal) from the ECU 2 via the amplifier 132. Similarly, the ECU 2 also includes amplifiers 140 and 142 as input / output buffers. The ECU 2 transmits a transmission signal (communication signal) to the ECU 1 via the amplifier 140, and receives the transmission signal (communication signal) from the ECU 1 via the amplifier 142.

[0044] In the ECU 1, the input of the signal waveform correction circuit 122a is connected to the output of the amplifier 132. A transmission signal from the ECU 2 is input to the signal waveform correction circuit 122a via the amplifier 132. The signal waveform of the transmission signal from the ECU 2 is modified by the signal distortion filter 104, and the signal waveform correction circuit 122a corrects this signal waveform modification. The ECU 1 receives the communication signal after being corrected by the signal waveform correction circuit 122a as a received signal.

[0045] The ECU 2 is similar to the ECU 1. That is, in the ECU 2, the input of the signal waveform correction circuit 122b is connected to the output of the amplifier 142. The transmission signal from the ECU 1 is input to the signal waveform correction circuit 122b via the amplifier 142. The signal waveform of the transmission signal from the ECU 1 is modified by the signal distortion filter 104, and the signal waveform correction circuit 122b corrects this signal waveform modification. The ECU 2 receives the communication signal after being corrected by the signal waveform correction circuit 122b as a received signal.

[0046] (Signal Filter Unit 102) The signal filter unit 102 includes a low-pass filter having low-pass characteristics or a band-reject filter having band-reject characteristics. That is, in this embodiment, a low-pass filter or a band-reject filter is used as the signal distortion filter 104.

[0047] Referring to Fig. 2, the low-pass filter 150 can be, for example, a pattern filter formed on a transmission line. The pattern filter is formed, for example, by providing a portion where the width of the transmission line is narrowed or by providing a portion where the width of the transmission line is widened. Fig. 3 is a diagram showing an example of the frequency characteristics of a low-pass filter. In Fig. 3, the horizontal axis represents frequency and the vertical axis represents transmission loss. Referring to Fig. 3, the low-pass filter attenuates high-frequency power above a cutoff frequency f1.

[0048] Referring to Fig. 4, the band reject filter 152 may be, for example, an open stub filter 154 formed on a transmission line. The open stub filter 154 is a narrow-band filter provided on the transmission line and has an electrical length a. The open stub filter 154 is a band reject filter that exhibits short-circuit characteristics at a specific frequency (resonant frequency). Fig. 5 is a diagram showing an example of the frequency characteristics of the open stub filter. In Fig. 5, the horizontal axis represents frequency and the vertical axis represents transmission loss. Referring to Fig. 5, the open stub filter exhibits short-circuit characteristics at resonant frequency f2 and attenuates power at that frequency.

[0049] The resonant frequency f2 is controlled by the electrical length a of the open stub filter (see FIG. 4), and its bandwidth and depth are controlled by the width of the open stub filter. The shape of the open stub filter is set so that the resonant frequency f2 is located within a predetermined band.

[0050] In this way, the low-pass filter and the band-reject filter block high-frequency components. Therefore, these filters distort the rising and falling edges of the communication signal. That is, the cutoff frequency f1 and the resonant frequency f2 are set so as to distort the signal waveform of the communication signal by a predetermined amount.

[0051] 1 , as described above, security system 50 includes signal transforming unit 100 (signal distortion filter 104) and signal correcting unit 120 (signal waveform correcting circuit 122). The signal waveform of the communication signal transformed by signal transforming unit 100 is corrected by signal correcting unit 120.

[0052] FIG. 6 is a diagram illustrating changes in the signal waveform of a communication signal. Here, we consider a case where a communication signal transmitted from ECU 1 is received by ECU 2. However, the reverse may also apply to signal transmission and reception. From top to bottom, FIG. 6 shows examples of the transmitted waveform, the waveform immediately before input to the signal distortion filter 104 (see FIG. 1), the signal waveform modified by the signal distortion filter 104 (see FIG. 1), the input waveform to ECU 2 (signal waveform correction circuit 122 (see FIG. 1)), i.e., the waveform before signal correction, and the signal waveform (received waveform) corrected by the signal waveform correction circuit 122 (see FIG. 1). In each waveform diagram, the horizontal axis represents time, and the vertical axis represents voltage (V). The following signal waveform diagrams have the same format.

[0053] 6 , for example, assume that a communication signal with a rectangular transmission waveform is transmitted. This communication signal is attenuated before being input to signal distortion filter 104, and the communication signal immediately before being input to signal distortion filter 104 has an attenuated rectangular waveform. When the attenuated communication signal is input to signal distortion filter 104, signal distortion filter 104 distorts the rising and falling edges of the signal. As a result, the communication signal that has passed through signal distortion filter 104 has a deformed signal waveform. The communication signal whose waveform has been distorted by signal distortion filter 104 is input to signal waveform correction circuit 122. The waveform of the signal input to signal waveform correction circuit 122 (input waveform) is deformed and attenuated. Signal waveform correction circuit 122 corrects the signal waveform deformation (distortion) caused by signal distortion filter 104. Therefore, the received waveform is an attenuated rectangular wave. In other words, a rectangular wave corresponding to the transmitted waveform can be received.

[0054] In this way, the security system 50 includes the signal transformation unit 100 (signal distortion filter 104) and the signal correction unit 120 (signal waveform correction circuit 122), enabling normal communication. If the combination of the signal transformation unit 100 (signal distortion filter 104) and the signal correction unit 120 (signal waveform correction circuit 122) is correct (appropriate combination), normal communication will be difficult in any other combination (inappropriate combination). For example, if either the signal distortion filter 104 or the signal waveform correction circuit 122 is not present, an over-corrected or distorted signal will be received.

[0055] 7 , the system 40 in which the security system 50 is used includes a first in-vehicle device 60, a second in-vehicle device 70, and a wire harness 80. The wire harness 80 connects communication between the first in-vehicle device 60 and the second in-vehicle device 70. The wire harness 80 may be configured to directly connect the first in-vehicle device 60 and the second in-vehicle device 70, or may be configured to indirectly connect the first in-vehicle device 60 and the second in-vehicle device 70 via another communication line. From the perspective of the first in-vehicle device 60, for example, the second in-vehicle device 70 is another in-vehicle device, and from the perspective of the second in-vehicle device 70, for example, the first in-vehicle device 60 is another in-vehicle device.

[0056] The wire harness 80 includes a communication line 82, a first connector 84 connected to a first end of the communication line 82, and a second connector 86 connected to a second end of the communication line 82. The first connector 84 includes a housing 84a, and the second connector 86 includes a housing 86a.

[0057] The first in-vehicle device 60 includes a first communication unit 62, a first electrical board 64 on which the first communication unit 62 is mounted, and a connector 66 provided on the first electrical board 64. The connector 66 is connected to, for example, a first connector 84 of the wire harness 80. The first electrical board 64 is provided with a communication line 68 (transmission line) that electrically connects the first communication unit 62 and the connector 66.

[0058] The second in-vehicle device 70 includes a second communication unit 72, a second electrical board 74 on which the second communication unit 72 is mounted, and a connector 76 provided on the second electrical board 74. The connector 76 is connected to, for example, a second connector 86 of the wire harness 80. The second electrical board 74 is provided with a communication line 78 (transmission line) that electrically connects the second communication unit 72 and the connector 76.

[0059] 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 (communication control IC (Integrated Circuit)) mounted on the ECU for transmitting and receiving signals. Note that the first in-vehicle device 60 can correspond to, for example, the above-mentioned ECU 1, and the second in-vehicle device 70 can correspond to, for example, the above-mentioned ECU 2.

[0060] The first communication unit 62 includes a signal waveform correction circuit 122a. The second communication unit 72 includes a signal waveform correction circuit 122b. The communication control ICs provided in the first communication unit 62 and the second communication unit 72 each include a DSP (Digital Signal Processor) circuit for correcting the signal waveform. Therefore, the correction circuit (DSP circuit) of the communication control IC in the first communication unit 62 may be used as the signal waveform correction circuit 122a provided in the first in-vehicle device 60. Similarly, the correction circuit (DSP circuit) of the communication control IC in the second communication unit 72 may be used as the signal waveform correction circuit 122b provided in the second in-vehicle device 70. This facilitates implementation of the signal waveform correction circuit 122a in the first in-vehicle device 60 and also facilitates implementation of the signal waveform correction circuit 122b in the second in-vehicle device 70.

[0061] The communication between the first communication unit 62 and the second communication unit 72 is connected by a communication line 20. The communication line 20 includes a communication line 68, a communication line 78, and a communication line .

[0062] The above-described signal filter unit 102 (signal distortion filter 104) is provided, for example, in the second connector 86 of the wire harness 80. Referring to Fig. 8, the second connector 86 includes the above-described housing 86a (connector body) and the signal filter unit 102 provided within the housing 86a. An end of the communication line 82 is located within the housing 86a, and the signal filter unit 102 is provided, for example, on the communication line 82 within the housing 86a.

[0063] The signal filter unit 102 includes a low-pass filter or a band-reject filter. In the present embodiment, an open stub filter 154, which is a type of band-reject filter, is provided in the second connector 86. However, the signal filter unit 102 provided in the second connector 86 is not limited to the open stub filter 154 and may be, for example, a low-pass filter. The signal filter unit 102 may be provided in the first connector 84 of the wire harness 80 or in the communication line 82 of the wire harness 80.

[0064] The amount of correction by the signal waveform correction circuit 122a is set so as to appropriately correct the signal waveform deformed by the signal distortion filter 104. Similarly, the amount of correction by the signal waveform correction circuit 122b is set so as to appropriately correct the signal waveform deformed by the signal distortion filter 104. The amounts of correction by the signal waveform correction circuits 122a and 122b can be fixed (fixed values).

[0065] If an unauthorized device is connected to the first in-vehicle device 60 or the second in-vehicle device 70, the combination of the signal modification unit 100 (signal distortion filter 104) and the signal correction unit 120 (signal waveform correction circuit 122) becomes inappropriate. An example of an inappropriate combination is when the signal modification unit 100 (signal distortion filter 104) is not intervened. In this case, the signal waveform of the received signal (received waveform) is overcorrected by the signal waveform correction circuit 122. FIG. 9 is a diagram showing an example of a received waveform when the signal modification unit 100 (signal distortion filter 104) is not intervened. Referring to FIG. 9 , the signal waveform of the communication signal is deformed by overcorrection, resulting in degradation of signal quality. Another example of an inappropriate combination is when the signal correction unit 120 (signal waveform correction circuit 122) is not intervened. In this case, the received waveform is undercorrected. FIG. 10 is a diagram showing an example of a received waveform when the signal correction unit 120 (signal waveform correction circuit 122) is not intervened. Referring to FIG. 10, the signal waveform of the communication signal is deformed due to insufficient correction, and in this case too, the signal quality is degraded.

[0066] More specifically, suppose an unauthorized device is connected to the second connector 86 of the wire harness 80 in order to gain unauthorized access to the first in-vehicle device 60. In this case, the unauthorized device is unable to properly correct the signal waveform distortion caused by the signal distortion filter 104 (insufficient correction), thereby inhibiting normal communication with the first in-vehicle device 60. On the other hand, if the wire harness 80 is removed and an unauthorized device is connected to the first in-vehicle device 60 via another wire harness, the signal distortion filter 104 is no longer present. In this case, the signal waveform correction circuit 122a of the first in-vehicle device 60 overcorrects the signal waveform of the signal transmitted from the unauthorized device. The first communication unit 62 of the first in-vehicle device 60 receives a signal with degraded signal quality from the unauthorized device, thereby inhibiting communication with the unauthorized device. In other words, in this case as well, the unauthorized device is inhibited from properly communicating with the first in-vehicle device 60. When an unauthorized device is connected to the second vehicle-mounted device 70, normal communication is also restricted in the same manner as described above.

[0067] As described above, in the security system 50 according to this embodiment, the signal modification unit 100 modifies the signal waveform of a communication signal transmitted during communication. The signal correction unit 120 corrects the modified signal waveform. When the security system 50 includes the signal modification unit 100 and the signal correction unit 120, communication between the first communication unit 62 and the second communication unit 72 is performed normally. On the other hand, when an unauthorized device is connected to the first communication unit 62 or the second communication unit 72, either the signal modification unit 100 or the signal correction unit 120 is not present. For example, when the signal modification unit 100 is present but the signal correction unit 120 is not, the signal waveform of the communication signal is not corrected (undercorrected). Furthermore, when the signal modification unit 100 is present but the signal correction unit 120 is present, the signal waveform of the communication signal is overcorrected. In either case, signal quality deteriorates, thereby suppressing normal communication with unauthorized devices. Furthermore, the signal modification unit 100 and the signal correction unit 120 can be easily simplified in configuration. Therefore, according to the security system 50, communication security can be improved with a simpler configuration.

[0068] The signal transformation unit 100 can be configured to include a signal filter unit 102 that filters a communication signal, which is a signal within the communication band used for communication, and the signal correction unit 120 can be configured to include a signal waveform correction circuit 122 that corrects the signal waveform transformed by the signal filter unit 102. This makes it possible to easily achieve a simpler configuration.

[0069] Furthermore, the signal filter unit 102 may be configured to filter the communication signal transmitted by the first communication unit 62, and the second communication unit 72 may include a signal waveform correction circuit 122b. Similarly, the signal filter unit 102 may be configured to filter the communication signal transmitted by the second communication unit 72, and the first communication unit 62 may include a signal waveform correction circuit 122a. This eliminates the need to separately provide the signal waveform correction circuit 122, and allows for a configuration that includes the signal waveform correction circuit 122 with ease.

[0070] The signal filter unit 102 can be easily formed by configuring the signal filter unit 102 to include the low-pass filter 150 or the band-reject filter 152. Such a signal filter unit 102 can be easily provided in the communication line 82, the first connector 84, or the second connector 86 of the wire harness 80. Therefore, this configuration also makes it possible to easily achieve a simpler configuration.

[0071] (Second embodiment) Referring to FIG. 11 , a wire harness 200 according to this embodiment is a harness using a flat cable, and includes a communication line 210, a sheet-like holding member 220 that holds the communication line 210, a first connector 230, and a second connector 240.

[0072] The sheet-like holding member 220 is made of, for example, an insulating resin material (resin sheet). The communication line 210 is wired so as to extend along the longitudinal direction of the holding member 220.

[0073] The first connector 230 is connected to a first end of the communication line 210 , and the second connector 240 is connected to a second end of the communication line 210 .

[0074] The wire harness 200 further includes a signal filter section 250 similar to the above-described signal filter section 102 (see FIG. 1 ). The signal filter section 250 is used as a signal distortion filter 252. The signal distortion filter 252 includes an open stub filter 254.

[0075] In the present embodiment, the open stub filter 254 is formed in the communication line 210. The signal distortion filter 252 may be, for example, a low-pass filter instead of the open stub filter 254. The signal filter unit 250 (signal distortion filter 252) may be provided in a location other than the communication line 210. For example, the signal filter unit 250 (signal distortion filter 252) may be provided in the first connector 230 or the second connector 240 of the wire harness 200, or may be provided in the communication line 210 of the wire harness 200.

[0076] As a wire harness using a flat cable, an assembly harness such as e-STEALTH (registered trademark) is known. The wire harness 200 according to the present embodiment can also be configured using such an assembly harness.

[0077] According to this embodiment, it is possible to obtain a flat wire harness 200 that can improve communication security with a simpler configuration. The wire harness 200 according to this embodiment can be used in place of or together with the wire harness 200 (see FIG. 4 ) in the first embodiment.

[0078] The other configurations are the same as those in the first embodiment.

[0079] (Third embodiment) [Overall configuration] Referring to Figure 12, a security system 300 according to this embodiment includes a signal modification unit 160 instead of the signal modification unit 100 (see Figure 1), and a signal correction unit 180 instead of the signal correction unit 120 (see Figure 1).

[0080] The signal modifying unit 160 includes a signal waveform modifying circuit 162 that modifies the signal waveform of the transmission signal. The signal waveform modifying circuit 162 includes a signal waveform modifying circuit 162a provided in ECU1 and a signal waveform modifying circuit 162b provided in ECU2. The signal waveform modifying circuits 162a and 162b are collectively referred to as the "signal waveform modifying circuit 162." The signal waveform modifying circuit 162 may be provided in only one of ECU1 and ECU2. Here, an example in which the signal waveform modifying circuit 162 is provided in both ECU1 and ECU2 will be described.

[0081] The ECU 1 transmits a transmission signal (communication signal) to the ECU 2 via the amplifier 130, and receives the transmission signal (communication signal) from the ECU 2 via the amplifier 132. The ECU 2 transmits a transmission signal (communication signal) to the ECU 1 via the amplifier 140, and receives the transmission signal (communication signal) from the ECU 1 via the amplifier 142.

[0082] In the ECU 1, the output of the signal waveform modification circuit 162a is connected to the input of the amplifier 130. Therefore, the signal waveform of the transmission signal from the ECU 1 is modified by the signal waveform modification circuit 162a before being transmitted to the ECU 2.

[0083] The same applies to the ECU 2 as to the ECU 1. That is, the output of the signal waveform modification circuit 162b is connected to the input of the amplifier 140. Therefore, the signal waveform of the transmission signal from the ECU 2 is modified by the signal waveform modification circuit 162b before being transmitted to the ECU 1.

[0084] The signal correction unit 180 includes a signal filter unit 182. The signal filter unit 182 filters the communication signal, which is a signal within the communication band used for communication.

[0085] In the present security system 300, the signal filter unit 182 is used as a signal correction filter 184. That is, the signal filter unit 182 (signal correction unit 180) corrects the signal waveform that has been transformed by the signal waveform transformation circuit 162 (signal transformation unit 160). The signal correction filter 184 is provided on a transmission line for communication between the ECU 1 and the ECU 2. The signal waveforms of the transmission signals from the ECU 1 and the ECU 2 are corrected by the signal correction filter 184.

[0086] Specifically, the signal waveform of the transmission signal from the ECU 1 is transformed by the signal waveform transformation circuit 162, and the signal waveform is corrected by the signal correction filter 184. The ECU 2 receives the communication signal after correction by the signal correction filter 184 as a received signal. Similarly, the signal waveform of the transmission signal from the ECU 2 is transformed by the signal waveform transformation circuit 162, and the signal waveform is corrected by the signal correction filter 184. The ECU 1 receives the communication signal after correction by the signal correction filter 184 as a received signal.

[0087] (Signal Filter Unit 182) The signal filter unit 182 has the same configuration as the signal filter unit 182 in the first embodiment (see FIG. 1). That is, the signal filter unit 182 includes a low-pass filter or a band-reject filter. More specifically, in this embodiment, a low-pass filter or a band-reject filter is used as the signal correction filter 184.

[0088] In this embodiment, the signal waveform of the communication signal input to the signal filter unit 182 is modified by the signal waveform modification circuit 162. Therefore, the function of the signal filter unit 182 to distort the signal waveform is used as a function to correct the deformation of the signal waveform.

[0089] (Signal Waveform of Communication Signal) As described above, the security system 300 includes the signal transforming unit 160 (signal waveform transforming circuit 162) and the signal correcting unit 180 (signal correcting filter 184). The signal waveform of the communication signal transformed by the signal transforming unit 160 is corrected by the signal correcting unit 180.

[0090] FIG. 13 is a diagram illustrating changes in the signal waveform of a communication signal. Here, a case is considered in which a communication signal transmitted from ECU 1 is received by ECU 2. However, the reverse may also apply to signal transmission and reception. FIG. 13 illustrates, from top to bottom, examples of a transmitted waveform, a signal waveform modified by the signal waveform modification circuit 162 (see FIG. 12 ), a waveform immediately before being input to the signal correction filter 184 (see FIG. 12 ), a signal waveform corrected by the signal correction filter 184 (see FIG. 12 ), and a received waveform. Referring to FIG. 13 , for example, assume that a communication signal having a rectangular waveform is transmitted. The signal waveform of this communication signal is modified by the signal waveform modification circuit 162. The communication signal, whose waveform has been modified by the signal waveform modification circuit 162, is attenuated before being input to the signal correction filter 184. The communication signal is attenuated before being input to the signal distortion filter 104, and the waveform of the communication signal immediately before being input to the signal distortion filter 104 is an attenuated rectangular wave. When an attenuated communication signal is input to the signal distortion filter 104, the waveform of the communication signal immediately before being input to the signal correction filter 184 becomes an attenuated version of the distorted waveform. The signal correction filter 184 corrects the signal waveform deformation caused by the signal waveform modification circuit 162. The signal waveform after correction by the signal correction filter 184 becomes an attenuated rectangular wave. Therefore, the received waveform also becomes an attenuated rectangular wave. In other words, it becomes possible to receive a rectangular wave corresponding to the transmitted waveform.

[0091] In this way, the security system 300 includes the signal modification unit 160 (signal waveform modification circuit 162) and the signal correction unit 180 (signal correction filter 184), enabling normal communication. If the combination of the signal modification unit 160 (signal waveform modification circuit 162) and the signal correction unit 180 (signal correction filter 184) is considered to be a correct combination, normal communication will be difficult in any other combination (an invalid combination). For example, if either the signal waveform modification circuit 162 or the signal correction filter 184 is not present, an overcorrected or distorted signal will be received.

[0092] 14 , the system 40A in which the security system 300 is used includes a first in-vehicle device 60A, a second in-vehicle device 70A, and a wire harness 80A. The wire harness 80A connects the first in-vehicle device 60A and the second in-vehicle device 70A for communication. The wire harness 80A may be configured to directly connect the first in-vehicle device 60A and the second in-vehicle device 70A, or may be configured to indirectly connect the first in-vehicle device 60A and the second in-vehicle device 70A via another communication line. From the perspective of the first in-vehicle device 60A, for example, the second in-vehicle device 70A is another in-vehicle device, and from the perspective of the second in-vehicle device 70A, for example, the first in-vehicle device 60A is another in-vehicle device.

[0093] The wire harness 80A includes a communication line 82, a first connector 84 connected to a first end of the communication line 82, and a second connector 86 connected to a second end of the communication line 82. The first connector 84 includes a housing 84a, and the second connector 86 includes a housing 86a.

[0094] The first in-vehicle device 60A includes a first communication unit 62A, a first electrical board 64 on which the first communication unit 62A is mounted, and a connector 66 provided on the first electrical board 64. The connector 66 is connected to, for example, a first connector 84 of the wire harness 80A. The first electrical board 64 is provided with a communication line 68 (transmission line) that electrically connects the first communication unit 62A and the connector 66.

[0095] The second in-vehicle device 70A includes a second communication unit 72A, a second electrical board 74 on which the second communication unit 72A is mounted, and a connector 76 provided on the second electrical board 74. The connector 76 is connected to, for example, a second connector 86 of the wire harness 80A. The second electrical board 74 is provided with a communication line 78 (transmission line) that electrically connects the second communication unit 72A and the connector 76.

[0096] Assume that the first in-vehicle device 60A and the second in-vehicle device 70A are both ECUs. In this case, the first communication unit 62A and the second communication unit 72A include a PHY. The PHY is configured by a chip (communication control IC) mounted on the ECU for transmitting and receiving signals. Note that the first in-vehicle device 60A can correspond to, for example, the above-mentioned ECU 1, and the second in-vehicle device 70A can correspond to, for example, the above-mentioned ECU 2.

[0097] The first communication unit 62A includes a signal waveform modification circuit 162a. The second communication unit 72A includes a signal waveform modification circuit 162b. The communication control ICs provided in the first communication unit 62A and the second communication unit 72A each include a DSP (Digital Signal Processor) circuit for modifying signal waveforms. Therefore, the modification circuit (DSP circuit) of the communication control IC in the first communication unit 62A may be used as the signal waveform modification circuit 162a provided in the first in-vehicle device 60A. Similarly, the modification circuit (DSP circuit) of the communication control IC in the second communication unit 72A may be used as the signal waveform modification circuit 162b provided in the second in-vehicle device 70A. This facilitates implementation of the signal waveform modification circuit 162a in the first in-vehicle device 60A and also facilitates implementation of the signal waveform modification circuit 162b in the second in-vehicle device 70A.

[0098] The communication between the first communication unit 62A and the second communication unit 72A is connected by a communication line 20. The communication line 20 includes a communication line 68, a communication line 78, and a communication line .

[0099] The above-described signal filter unit 182 (signal correction filter 184) is provided, for example, in the second connector 86 of the wire harness 80A. Referring to Fig. 15 , the second connector 86 includes a housing 86a (connector body) and the signal filter unit 182 (signal correction filter 184) provided in the housing 86a. An end of the communication line 82 is located inside the housing 86a, and the signal filter unit 182 is provided, for example, on the communication line 82 inside the housing 86a.

[0100] The signal filter unit 182 includes a low-pass filter or a band-reject filter. In the present embodiment, the second connector 86 is provided with an open stub filter 154, which is a type of band-reject filter. However, the signal filter unit 182 provided in the second connector 86 is not limited to the open stub filter 154 and may be, for example, a low-pass filter. The signal filter unit 182 may be provided in the first connector 84 of the wire harness 80A or in the communication line 82 of the wire harness 80A.

[0101] The amount of deformation by the signal waveform modification circuit 162 is set to a value that can be appropriately corrected by the signal correction filter 184. Similarly, the amount of deformation by the signal waveform modification circuit 162 is also set to a value that can be appropriately corrected by the signal correction filter 184. The amount of deformation by the signal waveform modification circuit 162 and the signal waveform modification circuit 162 can each be fixed (a fixed value).

[0102] When an unauthorized device is connected to the first in-vehicle device 60A or the second in-vehicle device 70A, the combination of the signal modification unit 160 (signal waveform modification circuit 162) and the signal correction unit 180 (signal correction filter 184) becomes inappropriate. As an example of an inappropriate combination, for example, insufficient correction occurs when the signal correction unit 180 (signal correction filter 184) is not intervened. FIG. 16 is a diagram showing an example of a received waveform when the signal correction unit 180 (signal correction filter 184) is not intervened. Referring to FIG. 16, the signal waveform of the communication signal is deformed due to insufficient correction, resulting in degradation of signal quality. As another example of an inappropriate combination, for example, when the signal modification unit 160 (signal waveform modification circuit 162) is not intervened, the signal correction filter 184 performs overcorrection. FIG. 17 is a diagram showing an example of a received waveform when the signal modification unit 160 (signal waveform modification circuit 162) is not intervened. Referring to FIG. 17, the signal waveform of the communication signal is deformed due to overcorrection, resulting in degradation of signal quality.

[0103] More specifically, suppose an unauthorized device is connected to the second connector 86 of the wire harness 80A to gain unauthorized access to the first in-vehicle device 60A. In this case, the unauthorized device does not include the signal waveform modification circuit 162, and therefore the signal waveform of the signal transmitted from the unauthorized device is overcorrected by the signal correction filter 184. The first communication unit 62A of the first in-vehicle device 60A receives a signal with degraded signal quality from the unauthorized device, thereby restricting communication with the unauthorized device. In other words, in this case, the unauthorized device is restricted from communicating normally with the first in-vehicle device 60A. On the other hand, if the wire harness 80A is removed and an unauthorized device is connected to the first in-vehicle device 60A via a different wire harness, the signal correction filter 184 is no longer present. In this case, the unauthorized device is unable to properly correct the signal waveform modification performed by the signal waveform modification circuit 162 (undercorrection), thereby restricting normal communication with the first in-vehicle device 60A. When an unauthorized device is connected to the second vehicle-mounted device 70A, normal communication is also restricted in the same manner as described above.

[0104] In this way, the security system 300 according to this embodiment can also improve communication security with a simpler configuration.

[0105] The signal modifying unit 160 can be configured to include a signal waveform modifying circuit 162 that modifies the signal waveform of the communication signal, and the signal correcting unit 180 can be configured to include a signal filter unit 182 that filters the signal waveform modified by the signal waveform modifying circuit 162. This makes it possible to easily achieve a simpler configuration.

[0106] Furthermore, the first communication unit 62A includes a signal waveform modification circuit 162, which can be configured to modify the signal waveform of the communication signal transmitted by the first communication unit 62A. Similarly, the second communication unit 72A includes a signal waveform modification circuit 162, which can be configured to modify the signal waveform of the communication signal transmitted by the second communication unit 72A. This facilitates implementation of the signal waveform modification circuit 162, making it easy to configure the communication system including the signal waveform modification circuit 162. In this case, the signal filter unit 182 can be configured to be provided on the transmission line until the second communication unit 72A receives the communication signal from the first communication unit 62A, or on the transmission line until the first communication unit 62A receives the communication signal from the second communication unit 72A.

[0107] The other configurations are the same as those in the first embodiment.

[0108] In this embodiment, the flat wire harness shown in the second embodiment can also be used.

[0109] (Fourth embodiment) In the first embodiment, an example in which the signal transforming unit (signal distortion filter) is provided in the wire harness has been described. However, the present disclosure is not limited to such an embodiment. The signal transforming unit may be provided in, for example, an in-vehicle device.

[0110] An example of an in-vehicle device including a signal modification unit will be described with reference to Fig. 18. The in-vehicle device 400 according to this embodiment is an ECU. The in-vehicle device 400 has the same configuration as the ECU 1 or ECU 2 according to the first embodiment, except that it includes a signal modification unit 410.

[0111] The signal transformation unit 410 has a configuration similar to that of the signal transformation unit 100 (see FIG. 1 ) in the first embodiment. That is, the signal transformation unit 410 includes a signal filter unit 102 that filters a communication signal, which is a signal within the communication band used for communication. The signal filter unit 102 includes, for example, a low-pass filter or a band-reject filter. This signal filter unit 102 is used as a signal distortion filter 104.

[0112] When the in-vehicle device 400 communicates with another in-vehicle device, the signal transforming unit 410 (signal distortion filter 104 ) may be provided in the in-vehicle device 400 .

[0113] 19, the in-vehicle device 400 has a configuration similar to, for example, the first in-vehicle device 60 (see FIG. 7), except that it is provided with a signal transformation unit 410 (signal distortion filter 104). Specifically, the in-vehicle device 400 includes a communication unit 462, an electrical board 464 on which the communication unit 462 is mounted, and a connector 466 provided on the electrical board 464. The electrical board 464 is provided with a communication line 468 (transmission line) that electrically connects the communication unit 462 and the connector 466. The connector 466 includes a housing 466a (connector body).

[0114] The communication unit 462 includes a signal waveform correction circuit 122. The in-vehicle device 400 further includes the above-mentioned signal distortion filter 104. The signal filter unit 102 (signal distortion filter 104) is provided, for example, in a housing 466a of the connector 466. More specifically, an end of a communication line 468 is located within the housing 466a of the connector 466, and the signal filter unit 102 is provided, for example, on the communication line 468 within the housing 466a. The signal distortion filter 104 may be either a low-pass filter or a band-reject filter.

[0115] Even when the in-vehicle device 400 is configured in this manner, communication security can be improved with a simpler configuration.

[0116] The other configurations are the same as those in the first embodiment.

[0117] (Modification) The signal filter unit 102 (signal distortion filter 104) may be configured to be provided in a portion other than the connector 466, for example, on the electrical circuit board 464. With reference to Fig. 20 , an in-vehicle device 400A according to the modification differs from the in-vehicle device 400 (see Fig. 19 ) in the position where the signal filter unit 102 (signal distortion filter 104) is provided. The other configurations of the in-vehicle device 400A are similar to those of the in-vehicle device 400.

[0118] In the in-vehicle device 400A, the signal filter unit 102 (signal distortion filter 104) is provided on the communication line 468 of the electrical circuit board 464. The signal distortion filter 104 may be either a low-pass filter or a band-reject filter.

[0119] The in-vehicle device 400A according to the modified example also has the same effects as those of the fourth embodiment.

[0120] Fifth Embodiment In the third embodiment, the signal correction unit (signal correction filter) is provided in the wire harness. However, the present disclosure is not limited to such an embodiment. The signal correction unit may be provided in, for example, an in-vehicle device.

[0121] An example of an in-vehicle device including a signal correction unit will be described with reference to Fig. 21. The in-vehicle device 500 according to this embodiment is an ECU. The in-vehicle device 500 has a configuration similar to that of the ECU 1 or ECU 2 according to the third embodiment, except that the in-vehicle device 500 includes a signal correction unit 510.

[0122] The signal correction unit 510 has a configuration similar to that of the signal correction unit 180 in the third embodiment (see FIG. 12 ). That is, the signal correction unit 510 includes a signal filter unit 182 that filters a communication signal, which is a signal within the communication band used for communication. The signal filter unit 182 includes, for example, a low-pass filter or a band-reject filter. This signal filter unit 182 is used as a signal correction filter 184.

[0123] When the in-vehicle device 500 communicates with another in-vehicle device, the signal correction unit 510 (signal correction filter 184) may also be provided in the other in-vehicle device.

[0124] The signal correction filter 184 may be either a low-pass filter or a band-reject filter. As shown in the fourth embodiment, the signal correction filter 184 may be provided in the connector of the in-vehicle device 500, or may be provided on the electrical circuit board of the in-vehicle device 500.

[0125] Even when the in-vehicle device 500 is configured in this manner, communication security can be improved with a simpler configuration.

[0126] The other configurations are the same as those of the third embodiment.

[0127] (Modification) In the above embodiment, the number of communication lines may be plural.

[0128] In the above embodiment, an example has been described in which the amplifier of the in-vehicle device (ECU) functions as a buffer circuit (input / output buffer), but the present disclosure is not limited to such an embodiment. The amplifier of the in-vehicle device (ECU) may function as, for example, an amplification circuit. In this case, the transmission / reception circuit of the in-vehicle device (ECU) may be an amplifier circuit PA (Power Amplifier) / LNA (Low Noise Amplifier). Specifically, the amplifier of the transmission circuit in the in-vehicle device may be a PA, and the amplifier of the reception circuit may be a LAN.

[0129] In the above embodiment, the in-vehicle device is an ECU, but the present disclosure is not limited to such an embodiment. The in-vehicle device may be a device other than an ECU.

[0130] In the above embodiment, an example in which the signal waveform correction circuit or the signal waveform modification circuit is provided in the communication unit has been shown, but the present disclosure is not limited to such an embodiment and may be configured such that the signal waveform correction circuit or the signal waveform modification circuit is provided outside the communication unit.

[0131] Embodiments obtained by appropriately combining the techniques disclosed above are also included within the technical scope of the present disclosure.

[0132] 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 wordings described therein.

[0133] 20, 68, 78, 82, 210, 468 Communication line 40, 40A System 50, 300 Security system 60, 60A First in-vehicle device 62, 62A First communication unit 64 First electrical board 66, 76, 466 Connector 70, 70A Second in-vehicle device 72, 72A Second communication unit 74 Second electrical board 80, 80A, 200 Wire harness 84, 230 First connector 84a, 86a, 466a Housing 86, 240 Second connector 100, 160, 410 Signal transforming unit 102, 182, 250 Signal filter unit 104, 252 Signal distortion filter 120, 180, 510 Signal correcting unit 122, 122a, 122b Signal waveform correcting circuit 130, 132, 140, 142 Amplifier 150 Low-pass filter 152 Band-reject filter 154, 254 Open stub filter 162, 162a, 162b Signal waveform modification circuit 220 Holding member 184 Signal correction filter 400, 400A, 500 In-vehicle device 462 Communication unit 464 Electrical circuit board

Claims

1. A security system used in a system that connects a first communication unit and a second communication unit via a communication line, A signal deformation unit that deforms the signal waveform of the communication signal transmitted in the aforementioned communication, It includes a signal correction unit that corrects the signal waveform that has been deformed by the signal deformation unit, The signal deformation unit includes a signal filter unit that filters the communication signal, which is a signal within the communication band used for the communication, and which is exchanged between the first communication unit and the second communication unit, and deforms the signal waveform of the communication signal. The security system includes a signal waveform correction circuit that corrects the signal waveform that has been deformed by the signal filter unit.

2. The signal filter unit filters the communication signal transmitted by the first communication unit. The security system according to claim 1, wherein the second communication unit includes the signal waveform correction circuit.

3. A security system used in a system that connects a first communication unit and a second communication unit via a communication line, A signal deformation unit that deforms the signal waveform of the communication signal transmitted in the aforementioned communication, It includes a signal correction unit that corrects the signal waveform that has been deformed by the signal deformation unit, The signal deformation unit includes a signal waveform deformation circuit that deforms the signal waveform of the communication signal exchanged between the first communication unit and the second communication unit. The security system includes a signal correction unit that filters the signal waveform that has been deformed by the signal waveform deformation circuit.

4. The first communication unit includes the signal waveform transformation circuit, The signal waveform transformation circuit transforms the signal waveform of the communication signal transmitted by the first communication unit. The security system according to claim 3, wherein the signal filter unit is provided on the transmission line until the second communication unit receives the communication signal.

5. The security system according to any one of claims 1 to 4, wherein the signal filtering unit includes a low-pass filter or a band-reject filter.

6. The communication between the first communication unit and the second communication unit is connected by a wire harness. The aforementioned wire harness is The aforementioned communication line, Includes a connector connected to the end of the communication line, The security system according to any one of claims 1 to 4, wherein the signal filter unit is provided on the communication line or the connector.

7. The security system according to claim 6, wherein the wire harness further includes a sheet-like retaining member for holding the communication line.

8. The security system according to any one of claims 1 to 4, wherein the signal filter unit is provided on at least one of the first electrical circuit board on which the first communication unit is mounted, a connector provided on the first electrical circuit board, a second electrical circuit board on which the second communication unit is mounted, and a connector provided on the second electrical circuit board.

9. A wire harness that connects the communication between the first communication unit and the second communication unit, Communication lines and A connector connected to the end of the communication line, The communication line or connector includes a signal filter unit that filters the communication signal transmitted from the first communication unit to the second communication unit during the communication, The signal filter unit is a wire harness that modifies the communication signal so that it can be corrected by a signal waveform correction circuit between the signal filter unit and the second communication unit.

10. The wire harness according to claim 9, wherein the signal filter section includes a low-pass filter or a band-reject filter.

11. The wire harness according to claim 9 or 10, further comprising a sheet-like retaining member for holding the communication line.

12. A connector used in a system that connects a first communication unit and a second communication unit via a communication line, Housing and The housing includes a signal filter unit that filters the communication signal transmitted from the first communication unit to the second communication unit during the communication, The signal filter unit is a connector that deforms the communication signal so that it can be corrected by a signal waveform correction circuit between the signal filter unit and the second communication unit.

13. An in-vehicle device that communicates with other in-vehicle devices via a communication line, Includes a communication unit that communicates with the aforementioned other in-vehicle devices, The communication unit includes a signal waveform correction circuit that corrects the deformation of the signal waveform when the signal waveform of a communication signal transmitted from another in-vehicle device is deformed by a signal filter that filters the communication signal, which is a signal within the communication band used for the communication.

14. The in-vehicle device according to claim 13, further comprising a signal filter unit that filters the signal waveform of a transmission signal to be transmitted to the other in-vehicle device in order to deform it.

15. An in-vehicle device that communicates with other in-vehicle devices via a communication line, Includes a communication unit that communicates with the aforementioned other in-vehicle devices, The above-mentioned communication unit includes a signal waveform deformation circuit that deforms the signal waveform of a transmission signal to be transmitted to the other in-vehicle device, in an in-vehicle device.

16. The in-vehicle device according to claim 15, further comprising a signal filter unit that filters the signal waveform of a communication signal transmitted from the other in-vehicle device in order to correct the deformation of the signal waveform when the signal waveform of the communication signal transmitted from the other in-vehicle device is deformed.

17. The aforementioned communication signal is a square wave. The signal waveform deformed by the signal filter unit has a shape in which the rising and falling portions of the signal waveform are attenuated. The signal waveform corrected by the signal correction unit has a shape in which the rising and falling portions of the signal waveform are amplified. The security system according to claim 1.

18. The signal filter unit includes a pattern filter formed on the communication line. The security system according to claim 1.