Capacitive 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 capacitive sensor. The method includes: providing a capacitive sensor, turning on the power supply of the capacitive sensor, the capacitive sensor including a power supply, a driving voltage adjustment circuit and a capacitive sensor module; the driving voltage adjustment circuit is used to adjust the driving voltage input to the capacitive sensor module; multiple groups of driving voltages are input to the capacitive sensor module through the driving voltage adjustment circuit; the capacitance value of the capacitive sensor module under each group of driving voltages is measured to obtain multiple groups of capacitance values; the multiple groups of driving voltages are used as excitations, and the capacitance values ​​under each group of driving voltages are used as responses to generate PUF characteristic values. This method can solve the problem of effective implementation of PUF on sensors.

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 capacitive 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 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 for PUF on sensors is needed. Summary of the invention

[0004] Based on this, it is necessary to provide a capacitive sensor PUF characteristic value generation method, a capacitive sensor PUF key generation method, a capacitive sensor security verification method, and a capacitive sensor security verification device 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 capacitive sensor, comprising:

[0006] Providing a capacitive sensor, turning on the power of the capacitive sensor, the capacitive sensor comprising a power supply, a driving voltage adjustment circuit and a capacitive sensor module; the driving voltage adjustment circuit is used to adjust the driving voltage input to the capacitive sensor module;

[0007] Inputting multiple sets of driving voltages to the capacitive sensor module via the driving voltage adjustment circuit;

[0008] Measuring and obtaining the capacitance value of the capacitive sensor module under each set of driving voltages to obtain multiple sets of capacitance values;

[0009] The plurality of driving voltages are used as excitations, and the capacitance values ​​under each driving voltage are used as responses to generate PUF characteristic values.

[0010] The above-mentioned capacitive sensor PUF characteristic value generation method uses multiple groups of driving voltages as excitations, and multiple groups of capacitance values ​​of the capacitive sensor under different driving voltages as responses to generate PUF characteristic values. However, the capacitance values ​​under different driving voltages have unique and stable characteristics. In this way, the PUF characteristic value of the sensor is generated without increasing additional design and production costs, thereby reducing the PUF cost.

[0011] In one embodiment, the capacitance value of the capacitive sensor module under each set of driving voltages is measured to obtain multiple sets of capacitance values, specifically:

[0012] When the external pressure applied to the capacitive sensor is zero, the output voltage value of the voltage output terminal of the capacitive sensor module under each set of driving voltages is measured to obtain multiple sets of output voltage values, and the output voltage values ​​are equivalent to the capacitance values;

[0013] The generating of the PUF characteristic value specifically comprises taking the multiple groups of driving voltages as excitations and taking the output voltage value corresponding to each group of driving voltages as a response to generate the PUF characteristic value.

[0014] In the above embodiment, multiple groups of driving voltages are used as excitations, and the output voltage value of the voltage output end of the capacitive sensor module of the capacitive sensor under different driving voltages is equivalent to the capacitance value as a response to generate a PUF characteristic value. However, the capacitance value under different driving voltages has a unique and stable characteristic, so the PUF characteristic value of the sensor is generated in this way, and there is no need to increase additional design and production costs, thereby reducing the PUF cost.

[0015] In one embodiment, the capacitive sensor module includes a central capacitor, a peripheral capacitor, and two fixed capacitors, and the central capacitor, the peripheral capacitor and the two fixed capacitors form a capacitive Wheatstone bridge.

[0016] In one embodiment, the output voltage value V0=V+-V-, wherein V+ is the potential of the positive electrode of the voltage output end measured when the negative electrode of the voltage output end of the capacitive sensor is grounded, and V- is the potential of the negative electrode of the voltage output end measured when the positive electrode of the voltage output end of the capacitive sensor is grounded.

[0017] In one embodiment, the capacitance value of the capacitive sensor module under each set of driving voltages is measured to obtain multiple sets of capacitance values, specifically:

[0018] When the external pressure applied to the capacitive sensor is zero, the potential V+ of the positive electrode of the output voltage end of the capacitive sensor module is measured when the negative electrode of the output voltage end is grounded under each set of driving voltages, and the potential V- of the negative electrode of the output voltage end is measured when the positive electrode of the output voltage end of the capacitive sensor is grounded, to obtain the (V+, V-) group under each set of driving voltages, and the (V+, V-) group under each set of driving voltages is equivalent to the capacitance value under the corresponding driving voltage;

[0019] Multiple groups of (V+, V-) under multiple driving voltages are measured;

[0020] The generating of the PUF characteristic value specifically comprises taking the multiple groups of driving voltages as excitations and taking the (V+, V-) groups corresponding to each group of driving voltages as responses to generate the PUF characteristic value.

[0021] In the above embodiment, multiple groups of driving voltages are used as excitations, and the output voltage value of the voltage output end of the capacitive sensor module of the capacitive sensor under different driving voltages is equivalent to the capacitance value as a response to generate a PUF characteristic value. However, the capacitance value under different driving voltages has a unique and stable characteristic, so the PUF characteristic value of the sensor is generated in this way, and there is no need to increase additional design and production costs, thereby reducing the PUF cost.

[0022] In one embodiment, the capacitive sensor is a MEMS sensor or an NMES sensor; the capacitive sensor is a capacitive pressure sensor, a capacitive force sensor, a capacitive displacement sensor, a capacitive mass sensor, a capacitive strain sensor, a capacitive flow sensor, a capacitive torque sensor, a capacitive vibration sensor, a capacitive liquid level sensor, a capacitive gyroscope, a capacitive gas sensor, a capacitive magnetic sensor, a capacitive biosensor, a capacitive humidity sensor, a capacitive temperature sensor, a capacitive chemical sensor, a capacitive acceleration sensor or a capacitive inertial sensor.

[0023] In a second aspect, the present application provides a capacitive sensor PUF key generation method, comprising:

[0024] Combining the PUF characteristic values ​​obtained by the PUF characteristic value generation method generated by any one of the above embodiments to obtain multiple CRP stimulus-response pairs;

[0025] Performing analog-to-digital conversion on the response in the CRP stimulus-response pair to obtain bit data;

[0026] The bit data is processed using a hash algorithm to generate a PUF key.

[0027] The above-mentioned capacitive 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.

[0028] In a third aspect, the present application provides a security verification method for a capacitive sensor, comprising:

[0029] A capacitive sensor to be tested is provided, a security verification device is connected to the capacitive sensor to be tested, and a power supply of the capacitive sensor is turned on, wherein the security verification device stores a PUF key of the capacitive sensor to be tested generated by any one of the above capacitive sensor PUF key generation methods;

[0030] The security verification device generates a first random number and sends the first random number to the capacitive sensor to be tested, and the capacitive sensor to be tested takes the first random number as a challenge and generates a first response;

[0031] The capacitive sensor to be tested encrypts the first random number to obtain a second response, and sends the second response to the security verification device, where the encryption key of the first random number is the first response;

[0032] Decrypting the second response using the PUF key stored in the security verification device as a decryption key to obtain a second random number;

[0033] The second random number is compared with the first random number, and if the two are the same, it is determined that the capacitive sensor to be tested is a safety device.

[0034] In the above-mentioned security verification method of the capacitive sensor, by using the PUF key and the challenge-response mechanism, the security verification of the capacitive sensor is achieved, the authenticity of the sensor and the security of the data are ensured, thereby enhancing the security and anti-attack capabilities.

[0035] In a fourth aspect, the present application provides a safety verification device for a capacitive sensor, wherein the safety verification device can use the above-mentioned safety verification method to perform safety verification on the capacitive sensor, and the safety verification device includes:

[0036] A memory for generating PUF keys of multiple capacitive sensors according to any one of the above embodiments;

[0037] A random number generation module, used to generate a first random number;

[0038] A decryption module, configured to decrypt a second response returned by the capacitive sensor using the PUF key to obtain a second random number;

[0039] A comparison module, used for comparing the second random number with the first random number to obtain a comparison result;

[0040] A display module is used to display the comparison result and / or display the first random number and the second random number.

[0041] In the security verification device of the above-mentioned capacitive sensor, by integrating PUF key storage, random number generation, decryption, comparison and display of the second random number with the first random number, efficient and accurate identity authentication and response checking of the capacitive sensor are achieved, thereby enhancing the security and reliability of sensor data, ensuring the safety performance of the sensor in various applications, and effectively preventing unauthorized access and data tampering. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] 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.

[0043] Figure 1 A schematic diagram of a flow chart of a method for generating a PUF characteristic value of a capacitive sensor in one embodiment of the present application;

[0044] Figure 2 This is a schematic diagram of the structure of a capacitive sensor in one embodiment of the present application;

[0045] Figure 3 A graph showing the relationship between capacitance and pressure change according to an embodiment of the present application;

[0046] Figure 4 A relationship diagram of the change of the initial capacitance value when the driving voltage is different values ​​in one embodiment of the present application;

[0047] Figure 5 A schematic diagram of a flow chart of a method for determining a PUF characteristic value in one embodiment of the present application;

[0048] Figure 6 This is a schematic diagram of the structure of a capacitive sensor module in one embodiment of the present application;

[0049] Figure 7 A schematic diagram of a flow chart of a method for generating a PUF characteristic value in one embodiment of the present application;

[0050] Figure 8 A schematic diagram of a PUF key generation method in one embodiment of the present application;

[0051] Fig. 9 A schematic diagram of a flow chart of a safety verification method for a capacitive sensor in one embodiment of the present application;

[0052] Fig.10 It is a schematic diagram of the structure of a safety verification device for a capacitive sensor in one embodiment of the present application. DETAILED DESCRIPTION

[0053] 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.

[0054] 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 using 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.

[0055] 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 lack of effective implementation methods for solving PUF on sensors in the related art, a method for generating characteristic values ​​of capacitive sensor PUF is proposed, which can solve the effective implementation of PUF applications on wireless sensors while realizing the application of PUF key technology on capacitive MEMS / NMES sensors at a low cost.

[0056] In an exemplary embodiment, Figure 1 As shown, a method for generating a PUF characteristic value of a capacitive sensor is provided, which may include the following steps 102 to 108, wherein:

[0057] Step 102, providing a capacitive sensor and turning on the power of the capacitive sensor, the capacitive sensor includes a power supply, a driving voltage adjustment circuit and a capacitive sensor module; the driving voltage adjustment circuit is used to adjust the driving voltage input to the capacitive sensor module.

[0058] Among them, capacitive sensors are a type of 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). Capacitive MEMS / NMES 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. Capacitive MEMS / NMES sensors are widely used in many types of sensors and can measure physical quantities such as pressure, acceleration, force, and displacement.

[0059] In an exemplary embodiment, the structural diagram of the capacitive sensor can be as follows: Figure 2 As shown, the capacitive sensor includes a power supply, a driving voltage adjustment circuit and a capacitive sensor module; the driving voltage adjustment circuit is used to adjust the driving voltage of the input capacitive sensor module. The driving voltage adjustment circuit can adjust the driving voltage of the input capacitive sensor by adjusting the size of the resistor in the power control circuit (i.e., the driving voltage adjustment circuit) connected to the capacitive sensor, thereby adjusting the driving voltage of the input capacitive sensor. The resistors in the driving voltage adjustment circuit can be arranged in parallel or in series, or a variable resistance structure such as a sliding rheostat can be used.

[0060] The capacitive sensor may be a wireless capacitive sensor or a wired sensor. For capacitive sensors with different transmission modes, the capacitive sensor may be, but is not limited to, a capacitive MEMS sensor or an NMES sensor. The type of the capacitive sensor is not limited here, and the structure of the capacitive sensor is not specifically limited. The present application is described with the capacitive sensor being a capacitive MEMS sensor.

[0061] Further, the capacitive sensor is a MEMS sensor or an NMES sensor; the capacitive sensor is any one of a capacitive pressure sensor, a capacitive force sensor, a capacitive displacement sensor, a capacitive mass sensor, a capacitive strain sensor, a capacitive flow sensor, a capacitive torque sensor, a capacitive vibration sensor, a capacitive liquid level sensor, a capacitive gyroscope, a capacitive gas sensor, a capacitive magnetic sensor, a capacitive biosensor, a capacitive humidity sensor, a capacitive temperature sensor, a capacitive chemical sensor, a capacitive acceleration sensor or a capacitive inertial sensor.

[0062] Step 104 , inputting a plurality of sets of driving voltages to the capacitive sensor module via the driving voltage adjustment circuit.

[0063] Step 106 , measuring the capacitance value of the capacitive sensor module under each set of driving voltages to obtain multiple sets of capacitance values.

[0064] It is understandable that during the test, the pressure sensor changes due to pressure changes, and its equivalent capacitance changes, resulting in different pressure value outputs, such as Figure 3 As shown in FIG. 1 , a graph showing the relationship between capacitance and pressure change in an exemplary embodiment is shown, with pressure on the abscissa and capacitance on the ordinate. The capacitance value in the initial state is stable and varies due to the different materials and processes of different devices, which is suitable PUF source data, wherein curve 1 represents the relationship between the central capacitance and pressure change, and curve 2 represents the relationship between the peripheral capacitance and pressure change.

[0065] In order to determine the PUF characteristic value, different capacitance values ​​can be generated by adjusting the amplitude of the driving voltage. From the perspective of authentication scenarios, CRP can be a set of data, which comes from a series of central capacitance and peripheral capacitance values ​​generated under different driving voltages. The combined size of the data can range from the smallest 1 data to the entire data set. Figure 4 As shown, it is a relationship diagram of the change of initial capacitance value when the driving voltage is different values ​​in an exemplary embodiment, the horizontal axis is the driving voltage, and the vertical axis is the capacitance, wherein curve 1 represents the relationship between the central capacitance and the driving voltage, and curve 2 represents the relationship between the peripheral capacitance and the driving voltage.

[0066] Step 108 , using multiple sets of driving voltages as excitations and the capacitance values ​​under each set of driving voltages as responses to generate PUF characteristic values.

[0067] There may be multiple PUF characteristic values, and one PUF characteristic value may include a driving voltage and multiple capacitance values ​​under the driving voltage, as shown in Table 1.

[0068] Table 1: PUF characteristic values

[0069]

[0070] The above-mentioned method for generating PUF characteristic values ​​of capacitive sensors inputs a driving voltage to the capacitive sensor through a driving voltage adjustment circuit; at each driving voltage, multiple groups of driving voltages are input to the capacitive sensor module through the driving voltage adjustment circuit, and the capacitance value of the capacitive sensor module under each group of driving voltages is measured to obtain multiple groups of capacitance values, and the multiple groups of driving voltages are used as excitations, and the capacitance values ​​under each group of driving voltages are used as responses to generate PUF characteristic values, and the capacitance values ​​of the capacitive sensor under different driving voltages are different, but the capacitance values ​​under different driving voltages have unique and stable characteristics, and the driving voltage in the capacitive sensor is used as an excitation, and the capacitance value under the driving voltage is used as a response to generate the PUF characteristic value of the sensor, and no additional design and production costs are required, which reduces the PUF cost, and further, the response parameters are increased, and the uniqueness of the PUF and the difference of the PUF characteristic values ​​of different sensors are improved. It can also be used for capacitive sensors, as well as anti-counterfeiting, security authentication and device identification including the capacitive sensor to ensure network security.

[0071] Optionally, in an exemplary embodiment, as Figure 5 As shown, a method for determining a PUF characteristic value is provided, including steps 502 to 504, wherein:

[0072] Step 502, when the external pressure applied to the capacitive sensor is zero, measure the output voltage value of the voltage output terminal of the capacitive sensor module under each set of driving voltages to obtain multiple sets of output voltage values, and the output voltage values ​​are equivalent to capacitance values.

[0073] Wherein, when the external pressure applied to the capacitive sensor is zero, it can be under normal atmospheric pressure without additional pressure. The capacitive sensor module includes a central capacitor, a peripheral capacitor, and two fixed capacitors, and the central capacitor, the peripheral capacitor and the two fixed capacitors form a capacitive Wheatstone bridge, such as Figure 6 As shown, it is a schematic diagram of the structure of a capacitive sensor module in an exemplary embodiment, including a central capacitor C1, a peripheral capacitor C2 and two fixed capacitors C. It can be understood that the capacitive Wheatstone bridge is a bridge based on the principle of capacitance differential measurement, which is commonly used to measure the capacitance value of a capacitor and other circuit parameters. Its principle is based on the balance condition of the Wheatstone bridge, that is, the product of the resistance and capacitance in the four branches of the bridge is equal. By adjusting the capacitance value in the bridge, the bridge can be balanced to achieve the measurement of the capacitance to be measured. The differential capacitor structure is to improve sensitivity and linearity. Many capacitive accelerometers use a differential capacitor structure, that is, two or more capacitor plates are used to measure relative displacement. This structure can effectively eliminate the influence of common mode noise and temperature drift.

[0074] The output voltage value can be measured by existing methods, or it can be equivalently determined based on the potential of the positive pole of the voltage output end measured when the negative pole of the voltage output end of the capacitive sensor is grounded, and the potential of the negative pole of the voltage output end measured when the positive pole of the voltage output end of the capacitive sensor is grounded.

[0075] In an exemplary embodiment, the output voltage value can be determined based on the difference between the potential of the positive electrode of the voltage output terminal of the capacitive sensor when the negative electrode of the voltage output terminal is grounded and the potential of the negative electrode of the voltage output terminal of the capacitive sensor when the positive electrode of the voltage output terminal is grounded.

[0076] The output voltage value can be expressed as V0=V+-V-, where V+ is the potential of the positive electrode of the voltage output end of the capacitive sensor when the negative electrode of the voltage output end is grounded, and V- is the potential of the negative electrode of the voltage output end of the capacitive sensor when the positive electrode of the voltage output end is grounded. It should be noted that 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, and the test results of the capacitive sensor output voltage directly tested are also susceptible to slight changes due to the influence of external air pressure fluctuations. However, the use of V+ and V- combined equivalent output voltage can avoid the influence of external air pressure fluctuations on the test results, making the test results more accurate.

[0077] Step 504, generating the PUF characteristic value specifically includes taking multiple groups of driving voltages as excitations and taking the output voltage value corresponding to each group of driving voltages as a response to generate the PUF characteristic value.

[0078] In the above embodiment, multiple groups of driving voltages are used as excitations, and the output voltage value of the voltage output end of the capacitive sensor module of the capacitive sensor under different driving voltages is equivalent to the capacitance value as a response to generate a PUF characteristic value. However, the capacitance value under different driving voltages has a unique and stable characteristic, so the PUF characteristic value of the sensor is generated in this way, and there is no need to increase additional design and production costs, thereby reducing the PUF cost.

[0079] In order to meet the needs of different application scenarios, in addition to using multiple groups of driving voltages as excitations and the corresponding output voltage values ​​under each group of driving voltages as responses to generate PUF characteristic values, and using multiple groups of driving voltages as excitations and the capacitance values ​​under each group of driving voltages as responses to generate PUF characteristic values, optionally, in an exemplary embodiment, Figure 7 As shown, a method for generating a PUF characteristic value is provided, including steps 702 to 706, wherein:

[0080] Step 702, when the external pressure applied to the capacitive sensor is zero, measure the potential V+ of the positive electrode of the output voltage end when the negative electrode of the output voltage end of the capacitive sensor module is grounded under each set of driving voltages, and measure the potential V- of the negative electrode of the output voltage end when the positive electrode of the output voltage end of the capacitive sensor is grounded, to obtain the (V+, V-) group under each set of driving voltages, and the (V+, V-) group under each set of driving voltages is equivalent to the capacitance value under the corresponding driving voltage.

[0081] Step 704 , measuring and obtaining multiple groups of (V+, V−) groups under multiple groups of driving voltages.

[0082] Step 706, generating the PUF characteristic value specifically includes taking multiple groups of driving voltages as excitations and taking the (V+, V-) groups corresponding to each group of driving voltages as responses to generate the PUF characteristic value.

[0083] In the above embodiment, multiple groups of driving voltages are used as excitations, and the capacitive sensor uses the corresponding (V+, V-) groups under different driving voltages as responses to generate PUF characteristic values. However, the potential of the positive electrode of the output voltage terminal and the potential of the negative electrode of the output voltage terminal under different driving voltages have unique and stable characteristics, so that the PUF characteristic value of the sensor is generated without increasing additional design and production costs, thereby reducing the PUF cost.

[0084] 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:

[0085] Step 802: Combine the acquired PUF feature values ​​to obtain multiple CRP stimulus-response pairs.

[0086] 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.

[0087] Exemplarily, the capacitive sensor obtains a PUF characteristic value determined based on the PUF characteristic value generation method recorded in any of the above embodiments, and combines the obtained PUF characteristic values ​​to obtain multiple CRP stimulus-response pairs.

[0088] Step 804: Perform analog-to-digital conversion on the response in the CRP stimulus-response pair to obtain bit data.

[0089] Step 806: Process the bit data using a hash algorithm to generate a PUF key.

[0090] 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, 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).

[0091] 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.

[0092] Furthermore, the PUF key may also be stored in a security verification device, server, or cloud server of the capacitive sensor to perform security verification on the capacitive sensor.

[0093] 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 capacitive sensor is provided, such as Fig. 9 As shown, it includes steps 902 to 910, wherein:

[0094] Step 902, provide a capacitive sensor to be tested, connect a security verification device to the capacitive sensor to be tested, turn on the power of the capacitive sensor, and store the PUF key of the capacitive sensor to be tested generated by the above PUF key generation method in the security verification device.

[0095] The PUF key can be generated in the manner described in the above embodiments but is not limited thereto, which will not be described in detail here. The type of the capacitive sensor to be tested can be the capacitive sensor described in any of the above embodiments, and the structure of the capacitive sensor to be tested will not be described in detail here.

[0096] Step 904: The security verification device generates a first random number and sends it to the capacitive sensor to be tested. The capacitive sensor to be tested takes the first random number as a challenge and generates a first response.

[0097] 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.

[0098] Step 906: The capacitive 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.

[0099] 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.

[0100] Step 910: compare the second random number with the first random number. If the two are the same, it is determined that the capacitive sensor to be tested is a safety device.

[0101] In the above-mentioned security verification method of the capacitive sensor, by using the PUF key and the challenge-response mechanism, the security verification of the capacitive sensor is achieved, the authenticity of the sensor and the security of the data are ensured, thereby enhancing the security and anti-attack capabilities.

[0102] Furthermore, according to actual application requirements, the security verification of capacitive sensors can be: for the case of device (e.g., capacitive sensor) registration, that is, when used for the first time, the device will send 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.

[0103] 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.

[0104] Furthermore, in an exemplary embodiment, a safety verification device for a capacitive sensor is provided, such as Fig.10 As shown, a schematic diagram of the structure of a safety verification device for a capacitive sensor is provided. The safety verification device can use the above-mentioned safety verification method to perform safety verification on the capacitive sensor. The safety verification device includes:

[0105] The memory 1002 is used to store the PUF keys of the multiple capacitive sensors generated in any of the above embodiments.

[0106] 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 capacitive sensor to generate a first response.

[0107] The decryption module 1006 is used to decrypt the second response returned by the capacitive sensor using the PUF key to obtain a second random number; the second response is obtained after the capacitive sensor to be tested encrypts the first random number.

[0108] The comparison module 1008 is used to compare the second random number with the first random number to obtain a comparison result.

[0109] The display module 1010 is used to display the comparison result and / or display the first random number and the second random number.

[0110] Optionally, in an exemplary embodiment, when the capacitive sensor to be tested is a wireless MEMS sensor, the security verification device of the capacitive sensor also includes an antenna module and a communication module. The antenna module enables the device to transmit data wirelessly without physical connection, and the communication module enables it to exchange data with an external system, including sending data collected by the sensor and receiving external instructions.

[0111] The above-mentioned security verification device uses the first random number as the stimulus of the capacitive 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 capacitive sensor to be tested by comparing the first random number with the second random number. This method uses the PUF key and the challenge-response mechanism to achieve security verification of the capacitive sensor, ensure the authenticity of the sensor and the security of the data, thereby enhancing security and anti-attack capabilities.

[0112] 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 is not strictly limited in order, 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 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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 a PUF characteristic value of a capacitive sensor, characterized in that: include: Providing a capacitive sensor and turning on the power of the capacitive sensor, wherein the capacitive sensor includes a power supply, a driving voltage adjustment circuit and a capacitive sensor module; The driving voltage adjustment circuit is used to adjust the driving voltage input to the capacitive sensor module; Inputting multiple sets of driving voltages to the capacitive sensor module via the driving voltage adjustment circuit; the driving voltage adjustment circuit adjusting the driving voltage input to the capacitive sensor includes adjusting the size of the resistor in the driving voltage adjustment circuit connected to the capacitive sensor, thereby adjusting the driving voltage input to the capacitive sensor; Measuring and obtaining the capacitance value of the capacitive sensor module under each set of driving voltages to obtain multiple sets of capacitance values; Using the plurality of driving voltages as excitations and the capacitance value under each driving voltage as a response, generating a PUF characteristic value; The capacitance value of the capacitive sensor module under each set of driving voltages is measured to obtain multiple sets of capacitance values, specifically: When the external pressure applied to the capacitive sensor is zero, the output voltage value of the voltage output end of the capacitive sensor module under each set of driving voltages is measured to obtain multiple sets of output voltage values, and the output voltage values ​​are equivalent to the capacitance values; the generation of PUF characteristic values ​​is specifically to use the multiple sets of driving voltages as excitations and the corresponding output voltage values ​​under each set of driving voltages as responses to generate PUF characteristic values; the output voltage value V0=V+-V-, wherein V+ is the potential of the positive electrode of the voltage output end measured when the negative electrode of the voltage output end of the capacitive sensor is grounded, and V- is the potential of the negative electrode of the voltage output end measured when the positive electrode of the voltage output end of the capacitive sensor is grounded.

2. The PUF feature value generation method according to claim 1, characterized in that: The capacitive sensor module includes a central capacitor, a peripheral capacitor, and two fixed capacitors, and the central capacitor, the peripheral capacitor and the two fixed capacitors form a capacitive Wheatstone bridge.

3. The PUF feature value generation method according to claim 2, characterized in that: The capacitance value of the capacitive sensor module under each set of driving voltages is measured to obtain multiple sets of capacitance values, specifically: When the external pressure applied to the capacitive sensor is zero, the potential V+ of the positive electrode of the output voltage end of the capacitive sensor module is measured when the negative electrode of the output voltage end is grounded under each set of driving voltages, and the potential V- of the negative electrode of the output voltage end is measured when the positive electrode of the output voltage end of the capacitive sensor is grounded, to obtain the (V+, V-) group under each set of driving voltages, and the (V+, V-) group under each set of driving voltages is equivalent to the capacitance value under the corresponding driving voltage; Multiple groups of (V+, V-) under multiple driving voltages are measured; The generating of the PUF characteristic value specifically comprises taking the multiple groups of driving voltages as excitations and taking the (V+, V-) groups corresponding to each group of driving voltages as responses to generate the PUF characteristic value.

4. The method for generating a PUF characteristic value according to any one of claims 1 to 3, characterized in that: The capacitive sensor is a MEMS sensor or an NMES sensor; the capacitive sensor is a capacitive pressure sensor, a capacitive force sensor, a capacitive displacement sensor, a capacitive mass sensor, a capacitive strain sensor, a capacitive flow sensor, a capacitive torque sensor, a capacitive vibration sensor, a capacitive liquid level sensor, a capacitive gyroscope, a capacitive gas sensor, a capacitive magnetic sensor, a capacitive biosensor, a capacitive humidity sensor, a capacitive temperature sensor, a capacitive chemical sensor, a capacitive acceleration sensor or a capacitive inertial sensor.

5. A capacitive sensor PUF key generation method, 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 4 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.

6. The method for generating a capacitive sensor PUF key according to claim 5, characterized in that: The method also includes storing the PUF key in a security verification device of the capacitive sensor.

7. A safety verification method for a capacitive sensor, characterized in that: include: A capacitive sensor to be tested is provided, a security verification device is connected to the capacitive sensor to be tested, and a power supply of the capacitive sensor is turned on, wherein the security verification device stores a PUF key of the capacitive sensor to be tested generated by the PUF key generation method according to claim 5 or claim 6; The security verification device generates a first random number and sends the first random number to the capacitive sensor to be tested, and the capacitive sensor to be tested takes the first random number as a challenge and generates a first response; The capacitive sensor to be tested encrypts the first random number to obtain a second response, and sends the second response to the security verification device, where 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 capacitive sensor to be tested is a safety device.

8. A safety verification device for a capacitive sensor, characterized in that: The safety verification device uses the safety verification method of claim 7 to perform safety verification on the capacitive sensor, and the safety verification device includes: A memory for storing PUF keys of multiple capacitive sensors generated by the method of claim 6 or claim 5; A random number generation module, used to generate a first random number; A decryption module, configured to decrypt a second response returned by the capacitive 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.

Images