Information erasure device

Abstract

The present invention provides an information erasure device that can suppress false detections of fraudulent activity, regardless of the environment in which the device is installed. [Solution] The information erasure device 1 comprises a measuring unit 20, a determination unit 31, and an erasure unit 32. The measuring unit is configured to measure the temperature of the environment in which the non-volatile memory is located. The determination unit is configured to determine whether the temperature of the environment is above a predetermined specific temperature. The erasure unit is configured to erase the information stored in the non-volatile memory when the temperature of the environment is above the specific temperature.

Description

Technical Field

[0001] This disclosure relates to an information erasing device that erases information stored in a non-volatile memory.

Background Art

[0002] Conventionally, when a device storing information detects an illegal act against the device, techniques such as encrypting or erasing the information are known. For example, Patent Document 1 below proposes a technique for determining whether the power supply cut-off of a device is due to an illegal act based on whether the device vibrates after the power supply cut-off.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, as a result of the inventors' detailed examination, it has been found that the technique of Patent Document 1 above has a problem of being prone to misjudging illegal acts. For example, when such a device is mounted on a vehicle, vibration generated by the running of the vehicle is transmitted to the device, so vibration also occurs even when it is not an illegal act.

[0005] One aspect of this disclosure is to provide an information erasing device that can suppress misjudgment of illegal acts without depending on the environment in which the device is arranged.

Means for Solving the Problems

[0006] An information erasing device (1) according to one aspect of this disclosure includes a measurement unit (20), a determination unit (31), and an erasing unit (32). The measurement unit is configured to measure the temperature of the environment in which the non-volatile memory is located.

[0007] The determination unit is configured to determine whether or not the ambient temperature is above a predetermined specific temperature. The erase unit is configured to erase information stored in non-volatile memory when the ambient temperature is above a specific temperature.

[0008] In this case, someone attempting to illegally read the contents of non-volatile memory would likely melt the solder or other materials fixing the non-volatile memory by heating it, remove the non-volatile memory, and then analyze its contents. During this process, the temperature of the environment in which the non-volatile memory is located is expected to rise. This temperature would be significantly higher than what would be expected in the normal operating environment of non-volatile memory. Therefore, this disclosure detects this temperature rise by determining whether the ambient temperature exceeds a specific temperature.

[0009] With this configuration, since the presence of temperature is used to identify fraudulent activity, it is possible to suppress false positives of fraudulent activity. [Brief explanation of the drawing]

[0010] [Figure 1] This is a block diagram illustrating the schematic configuration of an information erasure device. [Figure 2] This is a flowchart of the information erasure process according to the first embodiment. [Figure 3] This is a flowchart of the information erasure process according to the second embodiment. [Modes for carrying out the invention]

[0011] Embodiments of this disclosure will be described below with reference to the drawings. [1. First Embodiment] [1-1. Structure] The information erasure device 1 shown in Figure 1 is a device that is installed in a vehicle such as a passenger car and erases the information stored in the non-volatile memory 10 when it is subjected to fraudulent activity. Fraudulent activity refers to, for example, an act of peeling off the non-volatile memory 10 and attempting to read the information stored in the non-volatile memory 10. In this embodiment, as a form of fraudulent activity, the act of heating the non-volatile memory 10 in order to peel it off will be described in detail.

[0012] The information erasure device 1 in this embodiment comprises at least one measuring unit 20 and a control unit 30. The information erasure device 1 is connected to an in-vehicle device equipped with a non-volatile memory 10. The in-vehicle device is, for example, an ECU. ECU is an abbreviation for Electronic Control Unit. In this embodiment, the non-volatile memory 10, the measuring unit 20, and the control unit 30 are arranged on the same printed circuit board and are each fixed to the printed circuit board using solder.

[0013] The non-volatile memory 10 stores arbitrary information. The stored information may be, for example, firmware. Firmware is, as an example, a program for driving actuators such as engines and motors.

[0014] The measurement unit 20 is a sensor that measures the temperature of the environment in which the non-volatile memory 10 is located. The temperature of the environment measured by the measurement unit 20 may be the temperature of the non-volatile memory 10 itself, or the temperature of the printed circuit board on which the non-volatile memory 10 is located. The measurement of the environment temperature may be performed continuously or at regular time intervals. The measurement unit 20 is located near the non-volatile memory 10.

[0015] The temperature measurement results from the measurement unit 20 are configured to be available to the control unit 30. Furthermore, the temperature measurement results from the measurement unit 20 may be used by any configuration, such as an SoC (System of a Chip) as described later.

[0016] The measurement unit 20 may be arranged at any position as long as it can detect that the non-volatile memory 10 is being heated. For example, the measurement unit 20 may be arranged adjacent to the non-volatile memory 10 on a printed circuit board, or may be arranged away from the non-volatile memory 10 not only on the printed circuit board. As the measurement unit 20, for example, a well-known temperature sensor or the like is used. The information erasure device 1 may include a plurality of measurement units 20.

[0017] The control unit 30 includes a determination unit 31 and an erasure unit 32 as part of the functions of the control unit 30. The determination unit 31 and the erasure unit 32 are circuits capable of executing the information erasure process described later with minimal power. Specifically, the determination unit 31 has a function of determining the presence or absence of fraud based on the temperature of the environment measured by the measurement unit 20. The erasure unit 32 has a function of erasing the information stored in the non-volatile memory 10 when there is fraud in the non-volatile memory 10. Note that the control unit 30 may be configured as a microcomputer when power for operation can be ensured.

[0018] In addition, the information erasure device 1 may further include at least one of a power generation unit 40, a power supply unit 50, and a SoC 60. SoC is an abbreviation for System on Chip. In the present embodiment, the power generation unit 40, the power supply unit 50, and the SoC 60 are arranged on the same printed circuit board as the non-volatile memory 10 and the like.

[0019] The power generation unit 40 has a function of generating power using energy supplied from the outside. The energy supplied to the power generation unit 40 may be energy due to fraud, for example, heat given to the information erasure device 1 when trying to peel off the non-volatile memory 10 by using a heat gun. In this case, the power generation unit 40 has a function of converting heat into electric power. Specifically, for example, a thermocouple is used as the power generation unit 40. The electric power generated by the power generation unit 40 is supplied to the control unit 30 and used for the control unit 30 to perform the information erasure process.

[0020] The power supply unit 50 supplies power to the control unit 30 and the SoC 60. As the power supply unit 50, for example, a known battery or the like is used. The SoC 60 reads the information stored in the non-volatile memory 10 and controls the device.

[0021] [1-2. Processing] Next, the information erasure process executed by the control unit 30 will be described using the flowchart of FIG. 2. This information erasure process is a process of determining the presence or absence of improper behavior and erasing information when improper behavior is recognized. The information erasure process is executed, for example, when the supply of power from the power generation unit 40 or the power supply unit 50 to the control unit 30 is started.

[0022] In S10 of FIG. 2, the determination unit 31 acquires the measurement result of the temperature of the environment in which the non-volatile memory 10 is disposed, measured by the measurement unit 20. Subsequently, in S11, the determination unit 31 compares the acquired measurement result of the environment temperature with a preset specific temperature, and determines whether the temperature of the environment in which the non-volatile memory 10 is disposed is equal to or higher than the specific temperature. Here, the specific temperature is a temperature that cannot normally rise during normal use of the non-volatile memory 10, but can rise due to improper behavior.

[0023] Specifically, the specific temperature is set to a temperature between the temperature assumed inside a vehicle in summer and the melting point temperature of solder. For example, the specific temperature is set within the range from 200°C to 350°C. If the specific temperature is set within such a range, when attempting to remove the non-volatile memory 10 due to improper behavior, the measurement unit 20 can detect that the temperature is equal to or higher than the specific temperature. Also, during normal use without improper behavior, the measurement unit 20 can detect that the temperature is lower than the specific temperature. That is, improper behavior can be accurately detected.

[0024] If the determination in S11 is No, that is, if the temperature of the environment is lower than the specific temperature, the determination unit 31 determines that the non-volatile memory 10 has not been subjected to improper behavior, and the process proceeds to S10. If the determination in S11 is Yes, that is, if the ambient temperature is above a specific temperature, the determination unit 31 determines that there has been an unauthorized act on the non-volatile memory 10 and proceeds to S12.

[0025] In S12, the erase unit 32 erases the information stored in the non-volatile memory 10 and terminates the process. [1-3. Effects] The first embodiment described in detail above provides the following effects.

[0026] (1a) The measurement unit 20 measures the temperature of the environment in which the non-volatile memory 10 is located. The determination unit 31 determines whether the temperature of the environment is above a predetermined specific temperature. The erase unit 32 erases the information stored in the non-volatile memory 10 when the temperature of the environment is above the specific temperature. The specific temperature is a temperature that cannot normally rise under normal use of the non-volatile memory 10, but can rise due to fraudulent activity that heats the non-volatile memory 10.

[0027] With this configuration, fraudulent activity can be identified using temperature. As a result, misidentification of fraudulent activity can be suppressed. (1b) The power generation unit 40 has the function of generating electricity using energy supplied from an external source. The control unit 30 uses the power supplied from the power supply unit 50 or the power generated by the power generation unit 40 to perform information erasure processing.

[0028] With this configuration, even if the information erasure device 1 does not have a power supply unit 50, or if the power supply unit 50 is removed before the non-volatile memory 10 is subjected to unauthorized access, the control unit 30 can still perform the information erasure process when unauthorized access occurs. As a result, information leakage due to unauthorized access can be suppressed.

[0029] (1c) The measuring unit 20 is positioned at any location where it can detect that the non-volatile memory 10 is being heated. For example, the measuring unit 20 may be positioned adjacent to the non-volatile memory 10 on the printed circuit board.

[0030] With this configuration, the measurement unit 20 can more accurately measure the temperature of the environment in which the non-volatile memory 10 is located. As a result, false positives of fraudulent activity can be more effectively suppressed.

[0031] (1d) The information erasure device 1 may be equipped with multiple measurement units 20. In this case, the determination unit 31 obtains the measurement result of the ambient temperature from at least one of the measurement units 20. The determination unit 31 determines that there has been unauthorized activity on the non-volatile memory 10 when at least one of the obtained ambient temperature measurement results is above a specific temperature.

[0032] With this configuration, the measurement unit 20 can more accurately measure the temperature of the environment in which the non-volatile memory 10 is located. As a result, false positives of fraudulent activity can be more effectively suppressed.

[0033] [2. Second Embodiment] [2-1. Differences from the First Embodiment] The second embodiment has the same basic configuration as the first embodiment, so the differences will be explained below. Note that the same reference numerals as in the first embodiment indicate the same components, and refer to the preceding description.

[0034] In the first embodiment described above, the determination unit 31 determines in S11 whether the temperature of the environment in which the non-volatile memory 10 is located is above a specific temperature. In contrast, the second embodiment differs from the first embodiment in that it determines whether the state in which the temperature of the environment is above a specific temperature has continued for a predetermined time or longer. Here, the predetermined time is set to suppress the misjudgment of fraudulent activity when the temperature of the environment is recognized as being above a specific temperature due to an accidental factor (e.g., noise). In other words, the predetermined time is set according to the duration of the conceivable accidental factor. For example, the predetermined time may be set to 5 seconds or to 1 minute.

[0035] [2-2. Processing] Next, the information erasure process that the control unit 30 of the second embodiment performs in place of the information erasure process of the first embodiment shown in Figure 2 will be explained using the flowchart in Figure 3. Note that the processes S10 and S12 in Figure 3 are the same as the processes in Figure 2, so some explanation is omitted.

[0036] Step S21 in Figure 3 corresponds to step S11 in Figure 2. In step S21, the determination unit 31 determines whether the state in which the ambient temperature is above a specific temperature has continued for a predetermined time or longer. Specifically, the determination unit 31 first compares the acquired ambient temperature measurement result with the specific temperature. If the ambient temperature is above the specific temperature, the determination unit 31 starts measuring the duration. For example, if the measurement unit 20 measures the ambient temperature at regular time intervals, the determination unit 31 calculates the duration based on that regular time and the number of consecutive times the acquired ambient temperature measurement result was above the specific temperature. Subsequently, the determination unit 31 compares the measured or calculated duration with a predetermined time and determines whether the duration is above the predetermined time.

[0037] If the determination in S21 is No, meaning that the ambient temperature is below or above a specified temperature for a predetermined period of time or longer, the determination unit 31 determines that the non-volatile memory 10 has not been subjected to any unauthorized activity and proceeds to S10.

[0038] If the determination in S21 is Yes, that is, if the ambient temperature remains above a specific temperature for a predetermined period of time or longer, the determination unit 31 determines that there has been an unauthorized act on the non-volatile memory 10 and proceeds to S12.

[0039] [2-3. Effects] The second embodiment described in detail above achieves the effect (1a) of the first embodiment described above, and further achieves the following effects.

[0040] (2a) The determination unit 31 determines whether the temperature of the environment in which the non-volatile memory 10 is located has remained above a specific temperature for a predetermined period of time or longer. If the duration is less than the predetermined period, the erase unit 32 does not erase the information. On the other hand, if the duration is the predetermined period or longer, the erase unit 32 erases the information. The predetermined period is set according to the duration of any foreseeable accidental factors.

[0041] With this configuration, if the ambient temperature rises above a certain temperature due to accidental factors, it will not be judged as cheating. As a result, misjudgments of cheating can be further reduced.

[0042] [3. Other Embodiments] Although embodiments of this disclosure have been described above, this disclosure is not limited to the embodiments described above and can be implemented in various modified forms.

[0043] (3a) In the above embodiment, the information erasure device 1 was mounted on a vehicle such as a passenger car and connected to an in-vehicle device, but it is not limited to this. For example, the information erasure device 1 may be located on a server that is permanently installed in a building.

[0044] (3b) In the above embodiment, the power generation unit 40 generated electricity using heat as energy supplied from the outside, but it is not limited to this. For example, the power generation unit 40 may have a function to convert external pressure into electricity. Specifically, the power generation unit 40 may be a piezoelectric element that converts pressure into electricity.

[0045] (3c) In the above embodiment, the information erasure device 1 included a power generation unit 40 and a power supply unit 50, but is not limited thereto. For example, the information erasure device 1 may include only one of the power generation unit 40 and the power supply unit 50.

[0046] [Technical concepts disclosed in this specification] [Item 1] An information erasure device (1) configured to erase information stored in a non-volatile memory (10), A measuring unit (20) configured to measure the temperature of the environment in which the non-volatile memory is located, A determination unit (31) configured to determine whether the temperature of the environment is above a predetermined specific temperature, An erase unit (32) configured to erase information stored in the non-volatile memory when the temperature of the environment is above the specified temperature, An information erasure device equipped with the following features. [Item 2] The information erasure device described in item 1, The determination unit is configured to determine whether the state in which the temperature of the environment is above the specified temperature has continued for a predetermined time or longer. The erasure unit is configured to erase the information when the temperature of the environment remains above the specified temperature for a predetermined period of time or longer. Information erasure device. [Item 3] An information erasure device as described in item 1 or item 2, A power generation unit (40) configured to generate electricity using energy supplied from an external source, Furthermore, The erasure unit is configured to erase the information using the electricity generated by the power generation unit. Information erasure device. [Item 4] An information erasure device described in any one of items 1 to 3, The non-volatile memory further comprises the aforementioned, The non-volatile memory is located near the measurement unit. Information erasure device. [Item 5] An information erasure device described in any one of items 1 to 4, The aforementioned information erasure device is an information erasure device mounted on a vehicle. [Explanation of symbols]

[0047] 1... Information erasure device, 10... Non-volatile memory, 20... Measurement unit, 30... Control unit, 31... Judgment unit, 32... Erasure unit, 40... Power generation unit, 50... Power supply unit, 60... SoC.

Claims

1. An information erasure device (1) configured to erase information stored in a non-volatile memory (10), A measuring unit (20) configured to measure the temperature of the environment in which the non-volatile memory is located, A determination unit (31) configured to determine whether the temperature of the environment is above a predetermined specific temperature, An erase unit (32) configured to erase information stored in the non-volatile memory when the temperature of the environment is above the specified temperature, An information erasure device equipped with the following features.

2. An information erasure device according to claim 1, The determination unit is configured to determine whether the state in which the temperature of the environment is above the specified temperature has continued for a predetermined time or longer. The erasure unit is configured to erase the information when the temperature of the environment remains above the specified temperature for a predetermined period of time or longer. Information erasure device.

3. An information erasure device according to claim 1 or claim 2, A power generation unit (40) configured to generate electricity using energy supplied from an external source, Furthermore, The erasure unit is configured to erase the information using the electricity generated by the power generation unit. Information erasure device.

4. An information erasure device according to claim 1 or claim 2, The non-volatile memory further comprises the aforementioned, The non-volatile memory is located near the measurement unit. Information erasure device.

5. An information erasure device according to claim 1 or claim 2, The aforementioned information erasure device is an information erasure device mounted on a vehicle.

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