Piezoresistive sensor PUF characteristic value and PUF key generation method

Abstract

The present application provides a method for generating PUF characteristic values ​​and PUF keys for a piezoresistive sensor. The method comprises: turning on the power supply of the piezoresistive sensor, the piezoresistive sensor comprises a power supply, a driving voltage adjustment circuit and a piezoresistive sensor structure, inputting a driving voltage U1 to the piezoresistive sensor via the driving voltage adjustment circuit; under the driving voltage U1, the pressure simulation structure simulates M1 groups of external pressure groups, obtains the resistance-pressure coefficient K of the piezoresistive sensor under each group of external pressure, and obtains the M1 group of resistance-pressure coefficient K; adjusts the driving voltage, repeats the above steps, until multiple resistance-pressure coefficients K under N groups of driving voltages are obtained; uses N groups of driving voltages as excitation, uses multiple K values ​​under each driving voltage as response, and generates PUF characteristic values. This method can solve the problem of effective implementation of PUF on the sensor.

Description

Technical Field

[0001] The present application relates to the field of information security technology, and in particular to a method for generating a PUF characteristic value and a PUF key of a piezoresistive sensor. Background Art

[0002] Physically Unclonable Function (PUF) has the characteristics of uniqueness and non-replicability, and has been successfully applied in the field of information security. It is a safe and effective encryption technology. The hardware identity is managed through the physical characteristics of the hardware PUF (Physical Unclonable Function), and the root key is generated based on this characteristic. The key generation technology based on PUF allows the key to be kept within the device, which is highly secure. In addition, the cost of using PUF hardware is low, and it is also suitable for low-cost terminal devices such as wireless sensor devices.

[0003] In the related art, PUF key technology has been used in some large mobile terminal devices, such as using the data value after SRAM and DRAM initialization as PUF source data. However, this method is not suitable for small terminals, such as sensors. Therefore, an effective implementation method that can solve the PUF application on sensors is needed. Summary of the invention

[0004] Based on this, it is necessary to provide a piezoresistive sensor PUF characteristic value generation method, a piezoresistive sensor PUF key generation method and a piezoresistive sensor security verification method that can solve the above-mentioned technical problems and effectively implement the PUF on the sensor.

[0005] In a first aspect, the present application provides a method for generating a PUF characteristic value of a piezoresistive sensor, comprising:

[0006] Step A: providing a piezoresistive sensor, turning on the power supply of the piezoresistive sensor, wherein the piezoresistive sensor comprises a power supply, a driving voltage adjustment circuit and a piezoresistive sensor structure; the driving voltage adjustment circuit is used to adjust the driving voltage input to the piezoresistive sensor; the piezoresistive sensor structure comprises a pressure simulation structure and a Wheatstone bridge, and the pressure simulation structure is used to simulate the change of the external pressure to which the piezoresistive sensor is subjected;

[0007] Step B: inputting a driving voltage U1 to the piezoresistive sensor via the driving voltage adjustment circuit;

[0008] Step C1: Under the driving voltage U1, the pressure simulation structure simulates M1 group of external pressure groups, obtains the resistance-pressure coefficient K of the piezoresistive sensor under each group of external pressure, and obtains the M1 group of resistance-pressure coefficient K, each group of external pressure groups includes 2 different pressure values, and the resistance under each group of external pressure is 2;

[0009] Step D: adjusting the driving voltage, repeating steps B-C1, until a plurality of resistance-pressure coefficients K under N sets of driving voltages are obtained, the number of K being M1+M2+......+Mn, where N and M1-Mn are both positive integers;

[0010] Step E: using the N groups of driving voltages as excitations and multiple K values ​​under each driving voltage as responses to generate PUF characteristic values.

[0011] The above-mentioned method for generating PUF characteristic values ​​of piezoresistive sensors utilizes the fact that the resistance-pressure coefficient K of piezoresistive sensors under different driving voltages is also different, but K has a unique and stable characteristic under different driving voltages. The driving voltage in the piezoresistive sensor is used as excitation, and the resistance-pressure coefficient under different pressures is used as response, so as to generate the PUF characteristic value of the sensor. There is no need to increase additional design and production costs, thereby reducing the PUF cost.

[0012] In one embodiment, the values ​​of M1, M2, ..., Mn are the same or different.

[0013] In one embodiment, step B further includes:

[0014] Step C2: measuring an initial output voltage V0 of the piezoresistive sensor under a driving voltage U1, wherein the initial output voltage V0 is an output voltage when an additional external pressure applied to the piezoresistive sensor is zero;

[0015] The step D is to adjust the driving voltage, and repeat the steps B, C1 and C2 until N initial output voltages V0 under N groups of driving voltages and a plurality of resistance-pressure coefficients K under N groups of driving voltages are obtained, wherein the number of K is M1+M2+......+Mn;

[0016] The step D is to use the N groups of driving voltages as excitations, and the initial output voltage V0 and multiple K values ​​under each driving voltage as responses to generate a PUF characteristic value.

[0017] The above-mentioned method for generating PUF characteristic values ​​of piezoresistive sensors utilizes the fact that the resistance-pressure coefficient K of piezoresistive sensors under different driving voltages is also different, but K has a unique and stable characteristic under different driving voltages. The driving voltage in the piezoresistive sensor is used as an excitation, and the initial output voltage V0 and the resistance-pressure coefficient under different pressures are used as responses to generate the PUF characteristic values ​​of the sensor. It does not require additional design and production costs, which reduces the PUF cost. Furthermore, the response parameters are increased, and the uniqueness of the PUF and the difference of the PUF characteristic values ​​of different sensors are improved. In one embodiment, the initial output voltage V0=V+-V-, where V+ is the potential of the positive electrode of the output voltage terminal of the piezoresistive sensor measured when the negative electrode of the output voltage terminal is grounded, and V- is the potential of the negative electrode of the output voltage terminal of the piezoresistive sensor measured when the positive electrode of the output voltage terminal is grounded.

[0018] In one embodiment, step B further includes:

[0019] Step C3: When the external pressure applied to the piezoresistive sensor is zero and the driving voltage U1 is applied, the potential V+ of the positive electrode of the output voltage end of the piezoresistive sensor is measured when the negative electrode of the output voltage end of the piezoresistive sensor is grounded, and the potential V- of the negative electrode of the output voltage end of the piezoresistive sensor is measured when the positive electrode of the output voltage end of the piezoresistive sensor is grounded;

[0020] The step D is to adjust the driving voltage, and repeat the steps B, C1 and C3 until N V+ and N V- under N groups of driving voltages and a plurality of resistance-pressure coefficients K under N groups of driving voltages are obtained, wherein the number of K is M1+M2+......+Mn;

[0021] The step E is to use the N groups of driving voltages as excitations, and use V+ and V- under each driving voltage, and multiple K values ​​as responses to generate PUF characteristic values.

[0022] The above-mentioned method for generating PUF characteristic values ​​of piezoresistive sensors utilizes the fact that the resistance-pressure coefficient K of piezoresistive sensors under different driving voltages is also different, but K has a unique and stable characteristic under different driving voltages. The driving voltage in the piezoresistive sensor is used as excitation, and V+ and V- under each driving voltage, as well as multiple K values ​​are used as responses to generate the PUF characteristic values ​​of the sensor. There is no need to increase additional design and production costs, thereby reducing the PUF cost. Furthermore, the response parameters are increased, thereby improving the uniqueness of the PUF and the difference in PUF characteristic values ​​of different sensors.

[0023] In one embodiment, the resistance-pressure coefficient K=(R2-R1) / (P2-P1), wherein R1 is the resistance of the piezoresistive sensor when the external pressure it is subjected to is P1, and R2 is the resistance of the piezoresistive sensor when the external pressure it is subjected to is P2.

[0024] In one of the embodiments, the pressure simulation structure includes: a first pressure simulation electrode disposed at a diaphragm end of a cavity structure of the piezoresistive sensor;

[0025] A second pressure simulation electrode is disposed at a fixed end of the cavity structure of the piezoresistive sensor.

[0026] In one embodiment, the pressure simulation structure simulates the external pressure group of group M1 specifically as follows:

[0027] The voltage value between the first pressure simulation electrode and the second pressure simulation electrode is equivalent to the external pressure value borne by the piezoresistive sensor;

[0028] By adjusting the potential and / or current connected to the first pressure simulation electrode and the second pressure simulation electrode, different external pressure values ​​borne by the piezoresistive sensor are simulated to obtain the M1 group of external pressure groups.

[0029] In one embodiment, the adjusting the potential and / or current connected to the first pressure simulation electrode and the second pressure simulation electrode is specifically:

[0030] Grounding the first pressure simulation electrode, and adjusting the potential and / or current of the second pressure simulation electrode;

[0031] Alternatively, the second pressure simulation electrode is grounded, and the potential and / or current of the first pressure simulation electrode is adjusted.

[0032] In one embodiment, the resistance-pressure coefficient K=(V output 2-V output 1) / (V pressure simulation 2-V pressure simulation 1),

[0033] Among them, Vpressure simulation 1 and Vpressure simulation 2 are different voltage values ​​between the first pressure simulation electrode and the second pressure simulation electrode, Voutput 1 is the output voltage of the piezoresistive sensor when the voltage value between the first pressure simulation electrode and the second pressure simulation electrode is Vpressure simulation 1, and Voutput 2 is the output voltage of the piezoresistive sensor when the voltage value between the first pressure simulation electrode and the second pressure simulation electrode is Vpressure simulation 2.

[0034] In one embodiment, the piezoresistive sensor is a MEMS sensor or an NMES sensor; the piezoresistive sensor is a piezoresistive pressure sensor, a piezoresistive force sensor, a piezoresistive displacement sensor, a piezoresistive mass sensor, a piezoresistive strain sensor, a piezoresistive flow sensor, a piezoresistive torque sensor, a piezoresistive vibration sensor, a piezoresistive liquid level sensor, a piezoresistive gyroscope, a piezoresistive gas sensor, a piezoresistive magnetic sensor, a piezoresistive biosensor, a piezoresistive humidity sensor, a piezoresistive temperature sensor, a piezoresistive chemical sensor, a piezoresistive acceleration sensor or a piezoresistive inertial sensor.

[0035] The above-mentioned method for generating PUF characteristic values ​​of piezoresistive sensors utilizes the fact that the resistance-pressure coefficient K of piezoresistive sensors under different driving voltages is also different, but K has a unique and stable characteristic under different driving voltages. The driving voltage in the piezoresistive sensor is used as excitation, and the resistance-pressure coefficient under different pressures is used as response, so as to generate the PUF characteristic value of the sensor. There is no need to increase additional design and production costs, thereby reducing the PUF cost.

[0036] In a second aspect, the present application also provides a method for generating a PUF key for a piezoresistive sensor, characterized in that it includes:

[0037] Combining the PUF characteristic values ​​obtained by any of the above PUF characteristic value generation methods to obtain multiple CRP stimulus-response pairs;

[0038] Performing analog-to-digital conversion on the response in the CRP stimulus-response pair to obtain bit data;

[0039] The bit data is processed using a hash algorithm to generate a PUF key.

[0040] The above-mentioned piezoresistive sensor PUF key generation method can enhance the security and reliability of the PUF key by performing analog-to-digital conversion and hash algorithm processing on the CRP stimulus-response pair.

[0041] In a third aspect, the present application also provides a safety verification method for a piezoresistive sensor, comprising:

[0042] A piezoresistive sensor to be tested is provided, a security verification device is connected to the piezoresistive sensor to be tested, and a power supply of the piezoresistive sensor is turned on, wherein the security verification device stores a PUF key of the piezoresistive sensor to be tested generated by any one of the above-mentioned PUF key generation methods;

[0043] The security verification device generates a first random number and sends the first random number to the piezoresistive sensor to be tested, and the piezoresistive sensor to be tested takes the first random number as a challenge and generates a first response;

[0044] The piezoresistive sensor to be tested encrypts the first random number to obtain a second response, and sends the second response to the security verification device, wherein the encryption key of the first random number is the first response;

[0045] Decrypting the second response using the PUF key stored in the security verification device as a decryption key to obtain a second random number;

[0046] The second random number is compared with the first random number, and if the two are the same, it is determined that the piezoresistive sensor to be tested is a safety device.

[0047] In the above-mentioned security verification method of the piezoresistive sensor, the security verification of the piezoresistive sensor is achieved by using the PUF key and the challenge-response mechanism, thereby ensuring the authenticity of the sensor and the security of the data, thereby enhancing security and anti-attack capabilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0049] Figure 1 A schematic diagram of a flow chart of a method for generating a PUF characteristic value of a piezoresistive sensor in one embodiment of the present application;

[0050] Figure 2 This is a schematic diagram of the structure of a piezoresistive sensor in one embodiment of the present application;

[0051] Figure 3 A schematic diagram of a flow chart of a method for determining a PUF characteristic value in one embodiment of the present application;

[0052] Figure 4 This is a flowchart of a method for determining a PUF characteristic value in another embodiment of the present application;

[0053] Figure 5 A schematic diagram of an initial voltage and resistance-pressure function curve of a pressure sensor in one embodiment of the present application;

[0054] Figure 6 A schematic diagram of a resistance-pressure function curve generated under different driving voltages in one embodiment of the present application;

[0055] Figure 7 A schematic diagram of a pressure simulation structure in one embodiment of the present application;

[0056] Figure 8 A schematic diagram of a PUF key generation method in one embodiment of the present application;

[0057] Fig. 9 A schematic flow chart of a safety verification method for a piezoresistive sensor in one embodiment of the present application;

[0058] Fig.10 It is a schematic diagram of the structure of a security verification device in one embodiment of the present application. DETAILED DESCRIPTION

[0059] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0060] It is understandable that PUF, or Physical Unclonable Functions, is an important type of hardware security technology that uses the inherent properties of silicon-based semiconductors to randomly extract unclonable physical features, similar to biological fingerprints, and is a unique identifier for each chip. It uses the inevitable tiny differences in semiconductor devices during the manufacturing process (such as transistor threshold voltage, interconnect length, capacitance, etc.) to generate unique and unpredictable outputs. These differences make the response of each device unique and cannot be completely replicated even with the same manufacturing process. Therefore, PUF can be used as a "fingerprint" for devices for security applications such as identity authentication, key generation, and data encryption.

[0061] In the related art, PUFs based on other hardware features include Static RAM static random access memory (SRAM), ring oscillator (RO), arbiter PUFs, coating PUFs and dynamic RAM dynamic random access memory (DRAM). However, the limitation of hardware resources of wireless sensors makes it impossible to effectively use PUFs based on SRAM and DRAM. Secondly, RO PUF technology that increases additional design and production costs is not suitable. Therefore, in view of the technical problem that there is a lack of effective implementation methods for PUF on sensors in the related art, a method for generating characteristic values ​​of PUF for piezoresistive sensors is proposed, which can solve the effective implementation of PUF applications on wireless sensors while realizing the application of PUF key technology on piezoresistive MEMS sensors at a low cost.

[0062] In an exemplary embodiment, Figure 1 As shown, a method for generating a PUF characteristic value of a piezoresistive sensor is provided, which may include the following steps:

[0063] Step A: Provide a piezoresistive sensor and turn on the power of the piezoresistive sensor. The piezoresistive sensor includes a power supply, a driving voltage adjustment circuit and a piezoresistive sensor structure. The driving voltage adjustment circuit is used to adjust the driving voltage input to the piezoresistive sensor. The piezoresistive sensor structure includes a pressure simulation structure and a Wheatstone bridge. The pressure simulation structure is used to simulate the changes in the external pressure on the piezoresistive sensor.

[0064] The structural diagram of the piezoresistive sensor in step A can be as follows: Figure 2 As shown. Piezoresistive sensor is a sensing technology based on the piezoresistive effect, which measures physical quantities by detecting changes in resistance. The piezoresistive effect refers to the change in resistance of a material when it is subjected to mechanical stress (such as tension, compression or shear force). Piezoresistive MEMS sensors are usually made of silicon material because silicon has good piezoresistive properties and is compatible with existing semiconductor processes, facilitating mass production and integration. Piezoresistive sensors can be wireless piezoresistive sensors and wired sensors. For piezoresistive sensors with different transmission methods, piezoresistive sensors can be but are not limited to piezoresistive MEMS sensors or piezoresistive NMES sensors.

[0065] Furthermore, the piezoresistive MEMS / NMES sensor can be any one of a MEMS / NMES pressure sensor, a MEMS / NMES force sensor, a MEMS / NMES acceleration sensor, a MEMS / NMES displacement sensor, a MEMS / NMES strain sensor, a MEMS / NMES flow sensor, or a MEMS / NMES torque sensor. The embodiments of the present application do not limit the type of the piezoresistive sensor, and do not specifically limit the structure of the piezoresistive sensor. The present application is described as a piezoresistive MEMS sensor.

[0066] Understandably, it is widely used in consumer electronics, industrial automation, medical equipment, aerospace and other fields. The advantages of piezoresistive MEMS sensors are their high sensitivity, high precision, miniaturization and reliability, so they play an important role in many application scenarios. For example, piezoresistive pressure sensors can be widely used in air pressure measurement (e.g., for weather stations, altimeters, drone flight control systems, etc.), hydraulic / pneumatic systems (e.g., for industrial automation, medical equipment, automotive engine management systems, etc.), liquid level measurement (e.g., for liquid level monitoring of containers such as water tanks and oil tanks) and medical equipment (e.g., for pressure monitoring in medical equipment such as sphygmomanometers, ventilators, infusion pumps, etc.).

[0067] Wheatstone bridge circuit: Four piezoresistive elements are usually connected to form a Wheatstone Bridge circuit. When the pressure changes, the resistance value of the piezoresistive element changes, and then the output voltage of the bridge changes. By detecting the output voltage of the bridge, the pressure can be indirectly measured. Conversely, the output voltage value of the Wheatstone bridge (i.e., the output voltage of the piezoresistive sensor structure) can be equivalent to the resistance value of the Wheatstone bridge (i.e., the resistance value of the piezoresistive sensor). The drive voltage adjustment circuit can adjust the drive voltage of the input piezoresistive sensor by adjusting the size of the resistor in the power control circuit (i.e., the drive voltage adjustment circuit) connected to the piezoresistive sensor, thereby adjusting the drive voltage of the input piezoresistive sensor. Among them, the resistors in the drive voltage adjustment circuit can be set in parallel or in series, or a variable resistance structure such as a sliding rheostat can be used.

[0068] The pressure simulation structure may include two pressure simulation electrodes, and the simulation form of the external pressure may be, but is not limited to, represented by the pressure difference of the simulated voltage of the two pressure simulation electrodes. It is understandable that the way to simulate the change of the external pressure on the MEMS piezoresistive sensor structure may also be to add a pressure-applying structure on the upper surface of the diaphragm of the MEMS piezoresistive sensor structure to achieve pressure simulation.

[0069] Step B: Input the driving voltage U1 to the piezoresistive sensor via the driving voltage adjustment circuit.

[0070] There are multiple driving voltages U1. Under a given driving voltage U1, an initial output voltage V0 with an external pressure of 0 (ie, under normal atmospheric pressure without additional pressure) can be obtained.

[0071] Step C1: Under the driving voltage U1, the pressure simulation structure simulates the M1 group of external pressure groups, obtains the resistance-pressure coefficient K of the piezoresistive sensor under each group of external pressure, and obtains the M1 group of resistance-pressure coefficient K. Each group of external pressure groups includes 2 different pressure values, and the resistance under each group of external pressure is 2.

[0072] The resistance under each set of external pressure can be understood as the equivalent resistance of the piezoresistive sensor, which can be represented by R1 and R2, and each set of external pressure group includes two different pressure values, which can be represented by P1 and P2. The resistance-pressure coefficient K under each set of external pressure can be determined according to the difference between the two resistances under each set of external pressure and the difference between the two pressure values ​​of each corresponding set of external pressure group.

[0073] It is understandable that, since it is difficult to implement different pressure values ​​on the sensor to calculate the resistance-pressure (or pressure coefficient) in actual applications, a voltage control circuit can be added to the sensor to simulate the pressure change by changing the local voltage of the piezoresistive sensor through the voltage control circuit. The linear relationship between the voltage change and the output voltage can be approximated to obtain the linear relationship between the pressure and the output voltage.

[0074] Step D: Adjust the driving voltage and repeat steps B-C1 until a plurality of resistance-pressure coefficients K under N sets of driving voltages are obtained, where the number of K is M1+M2+......+Mn, where N and M1-Mn are both positive integers.

[0075] The driving voltage may be adjusted according to actual needs. It should be noted that for each driving voltage, there is a corresponding initial output voltage V0, and there may be multiple resistance-pressure coefficients K.

[0076] It should be noted that, in an exemplary embodiment, the values ​​of M1, M2, ..., Mn are the same or different and can be adjusted according to actual needs to meet the needs of different scenarios.

[0077] Step E: Using N groups of driving voltages as stimuli and multiple K values ​​under each driving voltage as responses to generate PUF characteristic values.

[0078] Among them, the number of PUF characteristic values ​​can be multiple, and one PUF characteristic value can include a driving voltage and multiple K values ​​under the driving voltage, as shown in Table 1; it can also include a driving voltage, the output voltage of the piezoresistive sensor under the driving voltage when the external pressure additionally applied is zero, and multiple K values ​​under the driving voltage; it can also be a driving voltage, when the external pressure additionally applied by the piezoresistive sensor under the driving voltage is zero, the potential V+ of the positive electrode of the output voltage end of the piezoresistive sensor when the negative electrode of the output voltage end of the piezoresistive sensor is grounded, and the potential V- of the negative electrode of the output voltage end when the positive electrode of the output voltage end of the piezoresistive sensor is grounded, and multiple K values ​​under the driving voltage are measured.

[0079] Table 1: PUF characteristic values

[0080]

[0081] The above-mentioned method for generating PUF characteristic values ​​of piezoresistive sensors inputs a driving voltage to the piezoresistive sensor through a driving voltage adjustment circuit; under each driving voltage, the pressure simulation structure simulates an external pressure group to obtain the resistance-pressure coefficient of the piezoresistive sensor under each external pressure group, and adjusts the input driving voltage of the piezoresistive sensor to obtain multiple resistance-pressure coefficients under N groups of driving voltages, and uses the N groups of driving voltages as excitations, and uses multiple K values ​​under each driving voltage as responses to generate PUF characteristic values, that is, the resistance-pressure coefficient K of the piezoresistive sensor under different driving voltages is also different, but K has unique and stable characteristics under different driving voltages, and uses the driving voltage in the piezoresistive sensor as excitation, and uses the initial output voltage V0 and the resistance-pressure coefficient under different pressures as responses to generate the PUF characteristic value of the sensor, and does not need to increase additional design and production costs, thereby reducing the PUF cost, and further, increases the response parameters, improves the uniqueness of PUF and the difference of PUF characteristic values ​​of different sensors. It can also be used for piezoresistive sensors, as well as anti-counterfeiting, security authentication and device identification including the piezoresistive sensor to ensure network security.

[0082] In an exemplary embodiment, the piezoresistive sensor is a MEMS sensor or an NMES sensor; the piezoresistive sensor is a piezoresistive pressure sensor, a piezoresistive force sensor, a piezoresistive displacement sensor, a piezoresistive mass sensor, a piezoresistive strain sensor, a piezoresistive flow sensor, a piezoresistive torque sensor, a piezoresistive vibration sensor, a piezoresistive liquid level sensor, a piezoresistive gyroscope, a piezoresistive gas sensor, a piezoresistive magnetic sensor, a piezoresistive biosensor, a piezoresistive humidity sensor, a piezoresistive temperature sensor, a piezoresistive chemical sensor, a piezoresistive acceleration sensor or a piezoresistive inertial sensor.

[0083] Optionally, in an exemplary embodiment, as Figure 3 As shown, a method for determining a PUF characteristic value is provided. Based on the above embodiment, step B further includes:

[0084] Step C2: measuring an initial output voltage V0 of the piezoresistive sensor under the driving voltage U1, where the initial output voltage V0 is the output voltage when the external pressure applied to the piezoresistive sensor is zero;

[0085] Among them, the initial output voltage V0 can be determined according to the potential of the positive pole of the output voltage terminal measured when the negative pole of the output voltage terminal of the piezoresistive sensor is grounded, and the potential of the negative pole of the output voltage terminal measured when the positive pole of the output voltage terminal of the piezoresistive sensor is grounded, that is, it is determined according to the difference between the potential of the positive pole of the voltage terminal and the potential of the negative pole of the output voltage terminal.

[0086] Furthermore, the initial output voltage V0 can be expressed as:

[0087] V0=V+-V-, where V+ is the potential of the positive electrode of the output voltage terminal of the piezoresistive sensor when the negative electrode of the output voltage terminal is grounded, and V- is the potential of the negative electrode of the output voltage terminal of the piezoresistive MEMS sensor when the positive electrode of the output voltage terminal is grounded.

[0088] Step D is to adjust the driving voltage, and repeat step B, step C1 and step C2 until N initial output voltages V0 under N groups of driving voltages and multiple resistance-pressure coefficients K under N groups of driving voltages are obtained, where the number of K is M1+M2+......+Mn;

[0089] Step E is to use N groups of driving voltages as excitations, and the initial output voltage V0 and multiple K values ​​under each driving voltage as responses to generate PUF characteristic values.

[0090] As shown in Table 2, the PUF characteristic value includes a driving voltage, an output voltage of the piezoresistive sensor under the driving voltage when the external pressure additionally applied is zero, and a plurality of K values ​​under the driving voltage.

[0091] Table 2: PUF characteristic values

[0092]

[0093] Optionally, in an exemplary embodiment, the initial output voltage V0 of the piezoresistive sensor under the driving voltage U1 can also be measured. The initial output voltage V0 is the output voltage of the piezoresistive sensor under one atmospheric pressure, that is, V0 is the output voltage without applying any additional external pressure to the piezoresistive sensor. Accordingly, N groups of driving voltages are used as excitation, and the initial output voltage V0 of each driving voltage under one atmospheric pressure and multiple K values ​​are used as responses to generate PUF characteristic values.

[0094] In this way, in the method for generating the PUF characteristic value of the piezoresistive sensor, the resistance-pressure coefficient K of the piezoresistive sensor under different driving voltages is also different, but K has a unique and stable characteristic under different driving voltages. The driving voltage in the piezoresistive sensor is used as excitation, and the initial output voltage V0 and the resistance-pressure coefficient under different pressures are used as responses to generate the PUF characteristic value of the sensor. There is no need to increase additional design and production costs, which reduces the PUF cost. Furthermore, the response parameters are increased, which improves the uniqueness of the PUF and the difference in the PUF characteristic values ​​of different sensors.

[0095] Optionally, in an exemplary embodiment, as Figure 4 As shown, a method for determining a PUF characteristic value is provided. Based on the above embodiment, step B further includes:

[0096] Step C3: When the external pressure applied to the piezoresistive sensor is zero and the driving voltage U1 is applied, measure the potential V+ of the positive electrode of the output voltage end of the piezoresistive sensor when the negative electrode of the output voltage end of the piezoresistive sensor is grounded, and measure the potential V- of the negative electrode of the output voltage end of the piezoresistive sensor when the positive electrode of the output voltage end of the piezoresistive sensor is grounded.

[0097] Step D is to adjust the driving voltage, and repeat step B, step C1 and step C3 until N V+ and N V- under N groups of driving voltages and a plurality of resistance-pressure coefficients K under N groups of driving voltages are obtained, and the number of K is M1+M2+......+Mn;

[0098] Step E is to use N groups of driving voltages as excitations, V+ and V- at each driving voltage, and multiple K values ​​as responses to generate PUF characteristic values.

[0099] Among them, a PUF characteristic value includes a driving voltage, when the external pressure applied by the piezoresistive sensor under the driving voltage is zero, when the negative electrode of the output voltage end of the piezoresistive sensor is grounded, the potential V+ of the positive electrode of the output voltage end, and when the positive electrode of the output voltage end of the piezoresistive sensor is grounded, the potential V- of the negative electrode of the output voltage end is measured, and multiple K values ​​under the driving voltage. The excitation and response in this case are shown in Table 3.

[0100] Table 3: PUF characteristic values

[0101]

[0102] Optionally, in an exemplary embodiment, when the external pressure applied to the piezoresistive sensor is one atmospheric pressure and the driving voltage U1 is applied, the potential V+ of the positive electrode of the output voltage terminal of the piezoresistive sensor is measured when the negative electrode of the output voltage terminal of the piezoresistive sensor is grounded, and the potential V- of the negative electrode of the output voltage terminal of the piezoresistive sensor is measured when the positive electrode of the output voltage terminal of the piezoresistive sensor is grounded. Accordingly, N groups of driving voltages are used as excitation, and V+ and V- measured under atmospheric pressure, as well as multiple K values, are used as responses to generate PUF characteristic values.

[0103] In this method, the resistance-pressure coefficient K of the piezoresistive sensor under different driving voltages is also different, but K has a unique and stable characteristic under different driving voltages. By using N groups of driving voltages as excitations, V+ and V- under each driving voltage, and multiple K values ​​as responses, the PUF characteristic value of the sensor is generated, and no additional design and production costs are required, which reduces the PUF cost. Furthermore, compared with only using multiple K values ​​as responses, the response parameters are increased, and the uniqueness of PUF and the difference of PUF characteristic values ​​of different sensors are improved. In addition, since the test process generally occurs under normal atmospheric pressure (generally one atmosphere), the external atmospheric pressure will fluctuate with the influence of uncontrollable factors such as environmental temperature, humidity, altitude, etc., that is, the air pressure of the test environment is not a fixed value. The method of directly testing the output voltage of the piezoresistive sensor is also susceptible to slight changes due to the influence of external air pressure fluctuations. However, the method of using V+ and V- to combine equivalent output voltages can avoid the influence of external air pressure fluctuations on the test results, making the test results more accurate.

[0104] It can be understood that based on the PUF characteristic values ​​determined in the above-mentioned different ways, in the case of specifically determining the PUF characteristic values, a method for determining the resistance-pressure coefficient K is provided for the piezoresistive sensor. In an exemplary embodiment, the resistance-pressure coefficient can be determined by determining the pressure difference between the second external pressure P2 and the first external force P1, and the resistance difference between the second resistor R2 when the piezoresistive sensor is subjected to the second external pressure P2 and the first resistor R1 when the piezoresistive sensor is subjected to the first external pressure P1, according to the pressure difference and the ratio of the pressure difference.

[0105] Specifically, the resistance-pressure coefficient K can be expressed as:

[0106] K=(R2-R1) / (P2-P1), where R1 is the resistance of the piezoresistive sensor when the external pressure it withstands is P1 (i.e., the first external pressure), and R2 is the resistance of the MEMS piezoresistive sensor when the external pressure it withstands is P2 (i.e., the second external pressure).

[0107] It should be noted that the resistance-pressure coefficient K is a fixed value under ideal conditions, and the corresponding relationship between the initial voltage of the pressure sensor and the resistance-pressure function can be expressed as a straight line. In an exemplary embodiment, Figure 5 As shown, a pressure sensor initial voltage and resistance-pressure function curve is provided, wherein the horizontal axis represents pressure, the vertical axis represents resistance, and when the driving voltage remains unchanged, the relationship between resistance and pressure is a curve. In an exemplary embodiment, as Figure 6 As shown, multiple resistance-pressure function curves generated under different driving voltages are provided, wherein the horizontal axis represents pressure, the vertical axis represents resistance, and one driving voltage corresponds to one resistance-pressure function curve. The above determination method of the resistance-pressure coefficient K ensures the reliability of the data and simplifies the calculation.

[0108] It can be understood that the pressure simulation structure is used to simulate the change of the external pressure on the piezoresistive sensor. In an exemplary embodiment, a pressure simulation structure is provided, such as Figure 7 As shown, the pressure simulation structure includes a first pressure simulation electrode disposed at the diaphragm end of the cavity structure of the piezoresistive sensor, and a second pressure simulation electrode disposed at the fixed end of the cavity structure of the piezoresistive sensor.

[0109] Furthermore, based on this pressure simulation structure, the external pressure group of the M1 group can be simulated in the following ways:

[0110] The voltage value between the first pressure simulation electrode and the second pressure simulation electrode is equivalent to the external pressure value that the piezoresistive sensor is borne; by adjusting the potential and / or current connected to the first pressure simulation electrode and the second pressure simulation electrode, the different external pressure values ​​that the piezoresistive sensor is borne are simulated to obtain the M1 group of external pressure groups.

[0111] Among them, further adjusting the potential and / or current connected to the first pressure simulation electrode and the second pressure simulation electrode can be: grounding the first pressure simulation electrode and adjusting the potential and / or current of the second pressure simulation electrode; or grounding the second pressure simulation electrode and adjusting the potential and / or current of the first pressure simulation electrode.

[0112] It is understandable that a MEMS piezoresistive sensor usually includes a Wheatstone bridge, which includes four piezoresistors. When external pressure acts on the sensor, the resistance of these piezoresistors will change, causing the bridge to be unbalanced, thereby generating a voltage signal proportional to the pressure; under the action of external pressure, the resistance value of the piezoresistors of the piezoresistive sensor will change. This change can be used to measure pressure. Secondly, within a certain pressure range, there is a linear relationship between the change in resistance and the change in pressure, which enables a direct correspondence between the voltage value and the pressure value. That is, based on the working principle of the MEMS piezoresistive sensor, the application of the piezoresistive effect, the design of the Wheatstone bridge, and the linear relationship between voltage and pressure, the voltage value between the two pressure simulation electrodes can be directly equivalent to the external pressure value to which the MEMS piezoresistive sensor is subjected. This equivalent relationship provides a direct, efficient and accurate method for pressure measurement. Among them, by adjusting the potential and / or current connected to the first pressure simulation electrode and the second pressure simulation electrode, this flexible, accurate and cost-effective method can be used to simulate and test the performance of the MEMS piezoresistive sensor under different pressures.

[0113] Based on the above pressure simulation structure, considering that it is difficult to implement different pressure values ​​on the sensor to calculate the resistance-pressure coefficient in practical applications, a voltage control circuit can be added to the piezoresistive sensor. The voltage change between the two pressure simulation electrodes can be changed by this circuit to simulate the pressure change. The change in the output voltage is equivalent to the different resistances of the sensor. The linear relationship between the voltage change and the output voltage is used to approximate the linear relationship between the pressure and the output voltage, and the resistance-pressure coefficient K=(R2-R1) / (P2-P1) is equivalent.

[0114] In an exemplary embodiment, the resistance-pressure coefficient may be:

[0115] Resistance-pressure coefficient K=(Voutput2-Voutput1) / (Vpressuresimulation2-Vpressuresimulation1), wherein Vpressuresimulation1 and Vpressuresimulation2 are voltage values ​​between different first pressure simulation electrodes and second pressure simulation electrodes, Voutput1 is the output voltage of the MEMS piezoresistive sensor when the voltage value between the first pressure simulation electrode and the second pressure simulation electrode is Vpressuresimulation1, and Voutput2 is the output voltage of the MEMS piezoresistive sensor when the voltage value between the first pressure simulation electrode and the second pressure simulation electrode is Vpressuresimulation2. As described in the above embodiments, Voutput1 and Voutput2 can be equivalent to a set of (V+, V-) measured under the pressure simulation electrode voltage under the corresponding driving voltage, and Vpressuresimulation1 and Vpressuresimulation2 can be equivalent to the potential of the other pressure simulation electrode when the potential of one of the two pressure simulation electrodes is grounded. Determining the resistance-pressure coefficient in this way can simplify the coefficient calculation and ensure the reliability and accuracy of the coefficient.

[0116] Based on the PUF characteristic value generation method in any of the above embodiments, a PUF key generation method is provided, such as Figure 8 As shown, it includes steps 802 to 806, wherein:

[0117] Step 802: Combine the acquired PUF feature values ​​to obtain multiple CRP stimulus-response pairs.

[0118] The PUF characteristic value obtained can be determined based on the PUF characteristic value generation method recorded in any of the above embodiments, which will not be described in detail here. CRP: Challenge and Response Pair, refers to the pairing of independent challenges and responses during the device authentication process. The combination method can be implemented by the existing combination method, which will not be described in detail here.

[0119] Exemplarily, the piezoresistive sensor obtains a PUF characteristic value determined based on the PUF characteristic value generation method recorded in any of the above embodiments, and the obtained PUF characteristic values ​​are combined to obtain multiple CRP stimulus-response pairs.

[0120] Step 804: Perform analog-to-digital conversion on the response in the CRP stimulus-response pair to obtain bit data.

[0121] Step 806: Process the bit data using a hash algorithm to generate a PUF key.

[0122] Among them, the hash algorithm can convert an input of any length into an output of a fixed length. This output is called a hash value or hash value, which is used for authentication. This method can effectively prevent the key from being predicted or copied, thereby improving security. The hash algorithm can be, but is not limited to, any one of SM3, MD5 (Message Digest Algorithm 5), and RIPEMD (RACE Integrity Primitives Evaluation Message Digest).

[0123] In the above PUF key generation method, the security and reliability of the PUF key can be enhanced by performing analog-to-digital conversion and hash algorithm processing on the CRP stimulus-response pair.

[0124] Furthermore, the PUF key may also be stored in a security verification device, server, or cloud server of the piezoresistive MEMS sensor to perform security verification on the piezoresistive sensor.

[0125] It is worth noting that PUF can be used to verify the identity of the device, ensuring that only legitimate devices can access the system or network, and can be used to verify the integrity of the firmware, ensuring that the device loads authenticated firmware when it starts up, preventing malware or firmware tampering, and can also verify the authenticity of the product, etc. In order to ensure the performance and reliability of the sensor, the sensor needs to be securely verified. In an exemplary embodiment, a security verification method for a piezoresistive sensor is provided, such as Fig. 9 As shown, it includes steps 902 to 910, wherein:

[0126] Step 902, provide a piezoresistive sensor to be tested, connect a security verification device to the piezoresistive sensor to be tested, turn on the power of the piezoresistive sensor, and store the PUF key of the piezoresistive sensor to be tested in the security verification device.

[0127] The PUF key may be generated by, but is not limited to, the method described in the above embodiment, which will not be described in detail here.

[0128] Step 904: The security verification device generates a first random number and sends it to the piezoresistive sensor to be tested. The piezoresistive sensor to be tested takes the first random number as a challenge and generates a first response.

[0129] The first random number may be generated by a pseudo-random number generator or a time-based random number generator, which is not specifically limited here.

[0130] Step 906: The piezoresistive sensor to be tested encrypts the first random number to obtain a second response, and sends the second response to the security verification device. The encryption key of the first random number is the first response.

[0131] Step 908: Use the PUF key stored in the security verification device as a decryption key to decrypt the second response to obtain a second random number.

[0132] Step 910: compare the second random number with the first random number. If the two are the same, it is determined that the piezoresistive sensor to be tested is a safety device.

[0133] In the above-mentioned security verification method of the piezoresistive sensor, the security verification of the piezoresistive sensor is achieved by using the PUF key and the challenge-response mechanism, thereby ensuring the authenticity of the sensor and the security of the data, thereby enhancing security and anti-attack capabilities.

[0134] Furthermore, according to actual application requirements, the security verification of piezoresistive sensors can be: for the registration of a device (e.g., a piezoresistive sensor), when used for the first time, the device sends a challenge-response pair (CRP) generated by its PUF to the authentication server. The server compares these CRPs with the pre-stored CRPs to verify the authenticity of the device. If the match is successful, the device will be registered as a legitimate device and assigned a unique identifier.

[0135] Then, for actual application needs, there may be a situation where random numbers are used in combination with challenges in CRP. In this case, the verification server will generate a random number and use it as part of the challenge, combined with the random number and the incentive in CRP. Based on the combination of the random number and the incentive in CRP, the challenge is determined, a response is generated, and the response is returned to the server. The server regenerates the expected response with the same random number and compares it with the received response. In this method, random numbers are introduced on the basis of CRP to ensure that the challenge used for each verification is unique and prevent replay attacks. In addition, random numbers increase the security of the system, making it difficult for attackers to predict or guess the content of the challenge.

[0136] Furthermore, in an exemplary embodiment, a security verification device is provided, such as Fig.10 As shown, a schematic diagram of the structure of a safety verification device is provided. The safety verification device can use the above-mentioned safety verification method of the piezoresistive sensor to perform safety verification on the piezoresistive sensor. The safety verification device includes:

[0137] A memory 1002, used to store the PUF keys of the multiple piezoresistive sensors generated in any of the above embodiments;

[0138] The random number generation module 1004 is used to generate a first random number; wherein the first random number is used as an excitation of the piezoresistive sensor to be tested to generate a first response.

[0139] The decryption module 1006 is used to decrypt the second response returned by the piezoresistive sensor using the PUF key to obtain a second random number; the second response is obtained after the piezoresistive sensor to be tested encrypts the first random number.

[0140] A comparison module 1008, configured to compare the second random number with the first random number to obtain a comparison result;

[0141] The display module 1010 is used to display the comparison result and / or display the first random number and the second random number.

[0142] The above-mentioned security verification device uses the first random number as the excitation of the piezoresistive sensor to be tested to generate a first response, and uses the PUF key to decrypt the second response obtained after encryption based on the first random number to obtain a second random number, and performs security verification on the piezoresistive sensor to be tested by comparing the first random number and the second random number. This method uses the PUF key and the challenge-response mechanism to achieve security verification of the piezoresistive sensor, ensure the authenticity of the sensor and the security of the data, thereby enhancing security and anti-attack capabilities.

[0143] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0144] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0145] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0146] In one embodiment, a computer device is further provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above method embodiments when executing the computer program.

[0147] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0148] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it may be directly on the other component or there may also be a central component. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may be a central component at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in the specification of this application are for illustrative purposes only and do not represent the only implementation method.

[0149] In addition, the terms "first" and "second" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, device, product or equipment that includes a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units that are not listed, or optionally also includes other steps or units inherent to these processes, methods, products or equipment.

[0150] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first feature is directly in contact with the second feature, or the first feature and the second feature are indirectly in contact through an intermediate medium. Moreover, a first feature being “above”, “above” or “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below” or “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0151] Unless otherwise defined, all technical and scientific terms used in the specification of this application have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in the specification of this application includes any and all combinations of one or more related listed items.

[0152] The technical features of the above embodiments can be combined without changing the basic principles of the present application. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0153] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the scope of patent protection of the present application shall be subject to the attached claims.

Claims

1. A method for generating PUF characteristic values ​​of a piezoresistive sensor, characterized in that: include: Step A: providing a piezoresistive sensor and turning on the power of the piezoresistive sensor, wherein the piezoresistive sensor includes a power supply, a driving voltage adjustment circuit and a piezoresistive sensor structure; The driving voltage adjustment circuit is used to adjust the driving voltage input to the piezoresistive sensor; the piezoresistive sensor structure includes a pressure simulation structure and a Wheatstone bridge, and the pressure simulation structure is used to simulate the change of the external pressure on the piezoresistive sensor; Step B: inputting a driving voltage U1 to the piezoresistive sensor via the driving voltage adjustment circuit; Step C1: Under the driving voltage U1, the pressure simulation structure simulates the M1 group of external pressure groups, obtains the resistance-pressure coefficient K of the piezoresistive sensor under each group of external pressure, and obtains the M1 group of resistance-pressure coefficient K, each group of external pressure groups includes 2 different pressure values, and the resistance under each group of external pressure is 2; the determination method of the resistance-pressure coefficient K includes: K=(R2-R1) / (P2-P1), wherein R1 is the resistance of the piezoresistive sensor when the external pressure it bears is P1, and R2 is the resistance of the piezoresistive sensor when the external pressure it bears is P2; Step D: adjusting the driving voltage, repeating steps B-C1, until a plurality of resistance-pressure coefficients K under N sets of driving voltages are obtained, the number of K being M1+M2+......+Mn, where N and M1-Mn are both positive integers; Step E: using the N groups of driving voltages as excitations and multiple K values ​​under each driving voltage as responses to generate PUF characteristic values.

2. The PUF feature value generation method according to claim 1, characterized in that: The values ​​of M1, M2, ..., Mn may be the same or different.

3. The PUF feature value generation method according to claim 2, characterized in that: Step B also includes: Step C2: measuring an initial output voltage V0 of the piezoresistive sensor under a driving voltage U1, wherein the initial output voltage V0 is an output voltage when an additional external pressure applied to the piezoresistive sensor is zero; The step D is to adjust the driving voltage, and repeat the steps B, C1 and C2 until N initial output voltages V0 under N groups of driving voltages and a plurality of resistance-pressure coefficients K under N groups of driving voltages are obtained, wherein the number of K is M1+M2+......+Mn; The step D is to use the N groups of driving voltages as excitations, and the initial output voltage V0 and multiple K values ​​under each driving voltage as responses to generate a PUF characteristic value.

4. The PUF feature value generation method according to claim 3, characterized in that: The initial output voltage V0=V+-V-, wherein V+ is the potential of the positive electrode of the output voltage end measured when the negative electrode of the output voltage end of the piezoresistive sensor is grounded, and V- is the potential of the negative electrode of the output voltage end measured when the positive electrode of the output voltage end of the piezoresistive sensor is grounded.

5. The PUF feature value generation method according to claim 2, characterized in that: Step B also includes: Step C3: When the external pressure applied to the piezoresistive sensor is zero and the driving voltage U1 is applied, the potential V+ of the positive electrode of the output voltage end of the piezoresistive sensor is measured when the negative electrode of the output voltage end of the piezoresistive sensor is grounded, and the potential V- of the negative electrode of the output voltage end of the piezoresistive sensor is measured when the positive electrode of the output voltage end of the piezoresistive sensor is grounded; The step D is to adjust the driving voltage, and repeat the steps B, C1 and C3 until N V+ and N V- under N groups of driving voltages and a plurality of resistance-pressure coefficients K under N groups of driving voltages are obtained, wherein the number of K is M1+M2+......+Mn; The step D is to use the N groups of driving voltages as excitations, and use V+ and V- under each driving voltage, and multiple K values ​​as responses to generate PUF characteristic values.

6. The PUF feature value generation method according to claim 5, characterized in that: The pressure simulation structure comprises: a first pressure simulation electrode disposed at a diaphragm end of a cavity structure of the piezoresistive sensor; A second pressure simulation electrode is disposed at a fixed end of the cavity structure of the piezoresistive sensor.

7. The PUF feature value generation method according to claim 6, characterized in that: The pressure simulation structure simulates the external pressure group of the M1 group specifically as follows: The voltage value between the first pressure simulation electrode and the second pressure simulation electrode is equivalent to the external pressure value borne by the piezoresistive sensor; By adjusting the potential and / or current connected to the first pressure simulation electrode and the second pressure simulation electrode, different external pressure values ​​borne by the piezoresistive sensor are simulated to obtain the M1 group of external pressure groups.

8. The PUF feature value generation method according to claim 7, characterized in that: The step of adjusting the potential and / or current connected to the first pressure simulation electrode and the second pressure simulation electrode is specifically: Grounding the first pressure simulation electrode, and adjusting the potential and / or current of the second pressure simulation electrode; Alternatively, the second pressure simulation electrode is grounded, and the potential and / or current of the first pressure simulation electrode is adjusted.

9. The PUF feature value generation method according to claim 6, characterized in that: The resistance-pressure coefficient K=(V output 2-V output 1) / (V pressure simulation 2-V pressure simulation 1), Among them, Vpressure simulation 1 and Vpressure simulation 2 are different voltage values ​​between the first pressure simulation electrode and the second pressure simulation electrode, Voutput 1 is the output voltage of the piezoresistive sensor when the voltage value between the first pressure simulation electrode and the second pressure simulation electrode is Vpressure simulation 1, and Voutput 2 is the output voltage of the piezoresistive sensor when the voltage value between the first pressure simulation electrode and the second pressure simulation electrode is Vpressure simulation 2.

10. The PUF feature value generation method according to claim 1, characterized in that: The piezoresistive sensor is a MEMS sensor or an NMES sensor; the piezoresistive sensor is a piezoresistive pressure sensor, a piezoresistive force sensor, a piezoresistive displacement sensor, a piezoresistive mass sensor, a piezoresistive strain sensor, a piezoresistive flow sensor, a piezoresistive torque sensor, a piezoresistive vibration sensor, a piezoresistive liquid level sensor, a piezoresistive gyroscope, a piezoresistive gas sensor, a piezoresistive magnetic sensor, a piezoresistive biosensor, a piezoresistive humidity sensor, a piezoresistive temperature sensor, a piezoresistive chemical sensor, a piezoresistive acceleration sensor or a piezoresistive inertial sensor.

11. A method for generating a PUF key for a piezoresistive sensor, characterized in that: include: Combining the PUF characteristic values ​​obtained by the PUF characteristic value generation method according to any one of claims 1 to 10 to obtain a plurality of CRP stimulus-response pairs; Performing analog-to-digital conversion on the response in the CRP stimulus-response pair to obtain bit data; The bit data is processed using a hash algorithm to generate a PUF key.

12. The method for generating a PUF key for a piezoresistive sensor according to claim 11, characterized in that: The method also includes storing the PUF key in a security verification device of the piezoresistive sensor.

13. A safety verification method for a piezoresistive sensor, characterized in that: include: A piezoresistive sensor to be tested is provided, a security verification device is connected to the piezoresistive sensor to be tested, and a power supply of the piezoresistive sensor is turned on, wherein the security verification device stores a PUF key of the piezoresistive sensor to be tested generated by the PUF key generation method according to claim 11 or claim 12; The security verification device generates a first random number and sends the first random number to the piezoresistive sensor to be tested, and the piezoresistive sensor to be tested takes the first random number as a challenge and generates a first response; The piezoresistive sensor to be tested encrypts the first random number to obtain a second response, and sends the second response to the security verification device, wherein the encryption key of the first random number is the first response; Decrypting the second response using the PUF key stored in the security verification device as a decryption key to obtain a second random number; The second random number is compared with the first random number, and if the two are the same, it is determined that the piezoresistive sensor to be tested is a safety device.

14. A safety verification device for a piezoresistive sensor, characterized in that: The safety verification device can use the safety verification method described in claim 13 to perform safety verification on the piezoresistive sensor, and the safety verification device includes: A memory, used to store PUF keys of multiple piezoresistive sensors generated by the method of claim 11 or claim 12; A random number generation module, used to generate a first random number; A decryption module, configured to decrypt a second response returned by the piezoresistive sensor using the PUF key to obtain a second random number; A comparison module, used for comparing the second random number with the first random number to obtain a comparison result; A display module is used to display the comparison result and / or display the first random number and the second random number.

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