JPH10320516A - Electronic device provided with security function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the security and to perform the maintenance as well. SOLUTION: In an on-vehicle machine used for an automatic charge collecting system, a case 1 for housing an electronic circuit 2 is constituted of an upper case member 1a and a lower case member 1b, the upper case member 1a and the lower case member 1b are fixed by four special screws 3, and when the order of detaching the screws 3 are other than a predetermined order, data requiring the security are eliminated. Thus, the security is secured by providing the order of detaching the screws 3 and the maintenance of the electronic circuit 2 is performed by detaching the screws 3 in the normal order and opening the case 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device in which an electronic circuit requiring security is housed in a case.

[0002]

2. Description of the Related Art Conventionally, in an automatic toll collection system for automatically collecting a toll between a roadside device and an onboard device, the onboard device is configured by housing an electronic circuit in a case. , On-board device ID numbers, key data for encryption, balance data when a prepaid card is used, and other data requiring security.

In order to ensure the security of an electronic device such as an in-vehicle device, means for detecting that the case has been opened, for example, means for laying a wire on the inner surface of the case and detecting the breakage of the wire, or There is a case in which a photo sensor is provided in the case and means for detecting external light when the case is opened is provided, and when it is detected that the case is opened, data requiring security is erased. .

[0004]

In the above-described conventional configuration, after the data requiring security is erased, the data must be restored in order to use the electronic circuit again. In the case of the in-vehicle device, this recovery work requires a process of storing data in the in-vehicle device using the original data stored in the host computer.

In this type of electronic device, a case may be opened for maintenance. For example, in the case of an in-vehicle unit, it is necessary to open the case for investigating a communication error location, replacing electronic components, replacing the built-in battery, etc.When opening the case, data will be erased as described above, Each time, recovery work is required.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to enable maintenance without requiring the above-described restoration work and to ensure sufficient security.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, an electronic circuit (2) is provided.
The case (1) for housing the first and second case members (1)
a, 1b), and the first and second case members (1
a, 1b) are fixed by a plurality of screws (3), and when the order in which the screws (3) are removed is other than a predetermined order, security is secured for data stored in the electronic circuit (2). The operation is performed.

Therefore, security can be ensured by providing the order in which the screws are removed, and maintenance can be performed by removing the screws in the regular order and opening the case. According to the second aspect of the present invention, the circuit portion (26) of the electronic circuit (2) requiring security is covered with the lid (6) provided on the circuit board (20), 6) When the opening is detected, a security operation is performed on the data stored in the electronic circuit (2).

Therefore, security can be ensured by a security operation when the lid (6) is opened, and the circuit portion (2) in a portion where the lid (6) is not provided is provided.
1 to 25), maintenance can be performed. According to the third aspect of the present invention, the circuit unit (26) requiring security is integrated into one chip, and the bus line (2
6e) is configured as an internal bus line.

[0010] Therefore, by integrating the circuit section (26) requiring security into one chip, it is possible to prevent the reading of data using the probe and to secure security, and to secure the other circuit sections (21 to 21). 25) Maintenance can be performed. The electronic device described above can be used as an on-vehicle device used in a system for automatically collecting a fee between a road device and an on-vehicle device, as in the invention according to claim 4.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 shows an assembly structure diagram of an in-vehicle device according to a first embodiment of the present invention. The resin case 1 for housing an electronic circuit is composed of an upper case member 1a and a lower case member 1b. In the case 1, an electronic circuit 2 for automatically collecting a fee with a roadside machine is housed. The electronic circuit 2 includes various components (1 in FIG.
(Only one IC chip is shown).

When assembling the in-vehicle unit, as shown in the figure, four special screws (hereinafter simply referred to as screws) 3 are used to connect the upper case member 1a, the electronic circuit 2, and the lower case member 1b. Fix it. The in-vehicle device configured in this way is
It is attached to a predetermined position in a vehicle interior, for example, on a dashboard or inside a windshield.

In this embodiment, in order to detect that the screw 3 has been removed, metal members 4 having the shape shown in FIG. 2A are attached above and below each screw hole of the circuit board 20. (See FIG. 2B). When the upper case member 1a and the lower case member 1b are fixed by the screws 3 through the through holes of the upper and lower metal members 4 (4a, 4b) attached to the circuit board 20, the upper and lower metal members 4a , 4b
And the screw 3 contact each other, and the upper and lower metal members 4a, 4
b is electrically connected.

The metal member 4 below the screw hole of the circuit board 20
a is connected to a power supply line, and the upper metal member 4b is connected to a control circuit 26 described later. Therefore, as shown in FIG. 3, the switch 5 is constituted by the upper and lower metal members 4a and 4b and the screw 3, and when the screw 3 is removed, the switch 5 is turned off.
6 is input. Thus, the control circuit 26 detects that the screw 3 has been removed.

FIG. 4 shows a block configuration of the electronic circuit 2 in the vehicle-mounted device. The electronic circuit 2 includes an antenna 21 for communicating with a roadside device, and a transmitting / receiving circuit 2 for controlling communication.
2, a liquid crystal display (LCD) 23 and its driver 24 for notifying the user of the balance information and the abnormality information of the in-vehicle device, and a buzzer 25 for generating a buzzer sound for calling the user's attention. And a control circuit 26 for controlling the above-described components.

The control circuit 26 executes arithmetic processing necessary for automatic collection of a fee and security processing to be described later in accordance with a program stored in mask chrome (not shown).
PU 26a, data storage memory 26b for storing data such as in-vehicle device ID number and balance data when a prepaid card is used, data from CPU 26a is encrypted, and encrypted received data from road device is decoded. And a key data storage memory 26d for storing key data necessary for encrypting the data, and an encryption logic circuit 26c for communicating with the road device using the encrypted data. ing. The exchange of data between these components is performed by the bus line 2 as shown in FIG.
6e.

Each circuit shown in FIG. 4 operates by receiving a voltage from a vehicle-mounted battery (not shown) via a stabilized power supply circuit. It should be noted that the power supply may be performed using a battery instead of the power supply from the vehicle-mounted battery. In the case where the payment is performed using the IC card, the IC card is inserted and held in the case 1. Then, the control circuit 26 reads out data from the IC card and writes data in the IC card, thereby performing the payment.

FIG. 5 shows security processing performed in the CPU 26a. First, when the power is turned on and this process is started, it is determined whether or not all the screws 3 have been removed (step 101). Whether or not the screw 3 has been removed can be determined using the switch signal from the switch 5 shown in FIG. In this process, when the vehicle-mounted device is removed from the vehicle, the electronic circuit is taken out using a special driver, and then the power supply is performed, it is regarded as a fraudulent process, and a fraud handling process (step 105) described later is performed. Performed to ensure security.

If it is determined in step 101 that the screw 3 has not been removed, a process of monitoring whether or not the screw 3 has been incorrectly removed is performed. In addition, screw 3
Is determined based on whether or not the screws 3 have been removed in a predetermined order. First, it is monitored whether or not there is a newly removed screw 3 (step 1).
02). If there is a newly removed screw 3, the screw number set for the screw 3 is stored (step 103). Thereafter, the screw numbers are arranged in a predetermined order (for example, screw number 1 → screw number 3 → screw number 2).
→ It is determined whether or not the screw number is 4) (step 104). That is, it is determined whether or not the screws 3 are removed in a predetermined order. Then, when the screw numbers are in order, the process returns to step 102 to execute the above-described processing.

On the other hand, if the screw numbers are not in the proper order, a fraud handling process is performed (step 105). In this fraud handling process, a security operation is performed to erase data requiring security, such as the in-vehicle device ID number stored in the memories 26b and 26d, balance data when a prepaid card is used, and key data. In this case, a flag may be set to make those data unusable.

Therefore, in the above-described embodiment, the screw 3 is removed in a wrong order when the vehicle-mounted device is removed from the vehicle and the electronic circuit 2 is taken out using the special driver, and in a non-regular order using the special driver. In times of fraud,
It is possible to prevent theft of data stored in the memories 26b and 26d and falsification of the data. In the case where maintenance of the electronic circuit 2 is performed (for example, investigation of an abnormal portion of the circuit units 21 and 22 that communicate with the roadside device, replacement of electronic components, and the like), the screws 3 are removed in a regular order. The case 1 can be opened without performing the above-described fraud handling processing. (Second Embodiment) FIGS. 6A and 6B show a second embodiment of the present invention.
1 shows an embodiment. FIG. 6A is a conceptual plan view of an electronic component mounted on the circuit board 20, and FIG. 6B is a perspective view thereof.

In this embodiment, in addition to the configuration shown in the first embodiment, of the electronic components mounted on the circuit board 20, a circuit part requiring security, specifically, a control unit shown in FIG. The circuit 26 is covered with the lid 6, and a photodiode (light detecting means) 7 for detecting that the lid 6 is opened is mounted on the circuit board 20 in the lid 6. The lid 6 is fixed on the circuit board 20 with an adhesive.

As shown in FIG. 7, the photodiode 7 is connected in series with the resistors 8 and 9, and the voltage at the connection point between the photodiode 7 and the resistor 9 is input to the CPU 26a. When the lid 6 is opened and the photodiode 7 is exposed to external light, the current flowing through the photodiode 7 increases, and the voltage input to the CPU 26a increases. Thus, the CPU 26a can detect that the lid 6 has been opened.

The CPU 26a executes the processing shown in FIG. 8, determines whether or not the lid 6 has been opened based on the above-described input voltage (step 201), and performs an unauthorized response processing when the lid 6 has been opened (step 201). Step 202). This fraud handling process is the same as the process shown in step 105 of FIG.
Accordingly, in this embodiment, when the cover 6 provided on the circuit board 20 is opened to perform a fraud, a fraud handling process is performed, and thus sufficient security can be ensured. In addition, among electronic components mounted on the circuit board 20, the lid 6 is provided only for a circuit part requiring security, so that the other circuit parts 21 to 25 on the circuit board 20 are not covered. Maintenance can be performed.

The mounting position of the photodiode 7 is not limited to the position on the circuit board 20 but may be another position in the lid 6. For example, as shown in FIG. 9, the photodiode 7 may be provided on a chip of the CPU 26a. Further, the second embodiment may be configured alone without being combined with the first embodiment. (Third Embodiment) Although the security can be sufficiently secured by the first and second embodiments described above, if the security cannot be secured by that, the control circuit 26 will
As shown in the figure, if it is composed of a discrete circuit,
There is a problem that unencrypted raw data can be read by applying a probe to the bus line 26e.

Therefore, in this embodiment, in addition to the first and second embodiments, as shown in FIG. 10, the control circuit 26 is formed of one chip, and the bus line 26e is used as an internal bus line, so that the probe can be used. Reading of the used raw data is not possible. If the key data used when performing encryption is known to the outside, the data can be read from the external interface of the control circuit 26. Therefore, in order to ensure the security of the key data, It is preferable to make the key data variable. For example, a key list is prepared in the key data storage memory 26d, and randomly selected key data is used. The same key list is stored in the roadside machine, and the same key data is stored in the key list. And communicate with each other using encrypted data using the key data. Further, as shown in FIG. 11, a decoding circuit 26e may be provided to decode key data transmitted from a roadside device and perform encryption using the key data.

Also, in the third embodiment, it is also possible to constitute a single unit without combining with the first and second embodiments.

[Brief description of the drawings]

FIG. 1 is an assembly structure diagram of an in-vehicle device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a metal member 4 used for detecting that a screw 3 shown in FIG. 1 has been removed, and a state of attachment to a circuit board 20;

3 is an electrical connection diagram showing a configuration of a detection circuit using a switch 5 including metal members 4a and 4b and a screw 3 shown in FIG.

FIG. 4 is a diagram showing a block configuration of an electronic circuit 2 shown in FIG.

FIG. 5 is a flowchart showing a security process of a CPU 26a in FIG.

FIG. 6 is a diagram illustrating a conceptual configuration of a circuit board 20 according to a second embodiment of the present invention.

7 is an electrical connection diagram showing a configuration of a detection circuit using the photodiode 7 shown in FIG.

FIG. 8 is a flowchart illustrating security processing of a CPU 26a according to the second embodiment of the present invention.

FIG. 9 is a view showing a modification of the second embodiment of the present invention.

FIG. 10 shows a control circuit 26 according to a third embodiment of the present invention.
FIG. 3 is a diagram showing the configuration of FIG.

FIG. 11 is a control circuit 26 according to the third embodiment of the present invention.
It is a figure which shows the modification of.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Case, 1a ... Upper case member, 1b ... Lower case member, 2 ... Electronic circuit, 3 ... Screw, 4 ... Metal member, 5 ... Switch, 6 ... Lid, 7 ... Photodiode, 20 ... Circuit board, 26 ... Control circuit, 26a CPU, 26b data storage memory, 26c encryption logic circuit, 26d key storage memory.

Claims (4)

[Claims] An electronic device comprising an electronic circuit (2) housed in a case (1), wherein the case (1) includes a first case member (1a) and a second case member (1a).
The first case member (1a) and the second case member (1b) are fixed by a plurality of screws (3), and the screws (3) are removed. That the screw detection means (4a,
4b, 102), if the order in which the screws (3) are removed is other than the predetermined order, the security operation is performed on the data stored in the electronic circuit (2). An electronic device having a security function, characterized in that: 2. An electronic device comprising an electronic circuit (2) housed in a case (1), wherein the electronic circuit (2) includes circuit parts (21 to 21) mounted on a circuit board (20). 26), and the circuit portions (21 to 2)
6) The circuit portion (26) requiring security is covered with a lid (6) provided on the circuit board (20), and the lid detecting means detects that the lid (6) is opened. (7-9,
An electronic device having a security function, wherein a security operation is performed on data stored in the electronic circuit (2) upon detection of (201). 3. An electronic device comprising an electronic circuit (2) housed in a case (1), wherein said electronic circuit (2) has a circuit section (26) requiring security. The circuit unit (26) is a memory (26b, 26) for storing data requiring security.
d) and an arithmetic processing unit (26a) connected to the memories (26b, 26d) and the bus line (26e), and the circuit unit (26) requiring security is one chip An electronic device having a security function, wherein the bus line (26e) is configured as an internal bus line. 4. The electronic device according to claim 1, wherein the electronic device is an in-vehicle device used in a system for automatically collecting a fee between a road device and an in-vehicle device. An electronic device having a security function.