Authentication device, authentication method, and computer-readable storage medium

Abstract

The signal acquisition unit (21) acquires a biological signal. The authentication information generation unit (22) generates authentication information that differs depending on the individual of the living body, based on the biological signal acquired by the signal acquisition unit (21). The site information generation unit (23) generates site information that differs depending on the site of acquisition of the biological signal, even for the same individual, based on the biological signal acquired by the signal acquisition unit (21). The authentication unit (24) performs authentication based on the authentication information generated by the authentication information generation unit (22) and the site information generated by the site information generation unit (23).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an authentication technique using a biological signal. BACKGROUND

[0002] With the development of IoT (Internet of Things), the authentication of a subject is becoming diversified in various scenes and devices. Biological authentication using a feature of a body that can be measured as an image, such as face authentication or fingerprint authentication, is less burdensome for a subject than password authentication and the like. Therefore, biological authentication is becoming widespread with devices such as smartphones and smartwatches.

[0003] As a feature of a body, attempts to use a biological signal, i.e., an electrocardiogram (hereinafter, ECG: Electrocardiogram), obtained by measurement of electrical activity of a heart, for authentication have been progressing in recent years. In some countries, practical use of an authentication device based on an ECG is progressing. In addition, research on using a photoplethysmogram (hereinafter, PPG: Photoplethysmogram), which is a biological signal obtained by optically measuring behavior of a blood vessel accompanying a heartbeat, for authentication is also being conducted. Here, the ECG and the PPG are time series signals.

[0004] As described in Non-Patent Literatures 1 and 2, a biological signal such as an ECG and a PPG can sometimes be measured at various parts of a body. With this, an attacker can set a sensor at a place where a body of a subject who wants to be spoofed is touched and illegally conduct measurement of a biological signal. In addition, a biological signal is mostly processed as an electrical signal, and thus, as described in Non-Patent Literature 1, an attack is considered in which an attacker illegally generates a biological signal and inputs it to an authentication device.

[0005] Therefore, in the future, when authentication using a biological signal is widespread and diversified, an authentication method is needed that has a countermeasure against spoofing attacks based on illegally measured biological signals and illegally generated biological signals.

[0006] In Patent Literature 1 and Non-Patent Literature 3, an authentication having a countermeasure against a spoofing attack based on information illegally generated by an attacker is described.

[0007] In Patent Literature 1, it is described that, before conducting fingerprint authentication, it is confirmed that a PPG can be measured from a finger, thereby ensuring that a prompted fingerprint is not an artificially generated fingerprint but a fingerprint taken from a living body (a finger), and conducting authentication.

[0008] In Non-Patent Literature 3, it is described that it is confirmed that PPG can be measured by a camera and image processing simultaneously with face authentication, thereby ensuring that the subject being measured by the camera for face authentication is not an artificial object such as a mask but a living body (face), and performing authentication.

[0009] Prior Art Documents

[0010] Patent Documents

[0011] Patent Document 1: Japanese Patent Application Publication No. 2020-093114

[0012] Non-Patent Literature

[0013] Non-Patent Literature 1: S. Eberz et al. "Broken hearted: How to attack ECG biometrics". Network and Distributed System Security Symposium, pp. 1-15, 2017.

[0014] Non-Patent Literature 2: V. Hartmann et al. "Quantitative comparison of photoplethysmographic waveform characteristics: effect of measurement site". Frontiers in physiology, Vol. 10, pp. 198-205, 2019.

[0015] Non-Patent Literature 3: E. M. Nowara et al. "Ppgsecure: Biometric presentation attack detection using photopletysmograms". 12th IEEE International Conference on Automatic Face & Gesture Recognition, pp. 56-62, 2017. SUMMARY

[0016] Problems to be Solved by the Invention

[0017] The countermeasures against spoofing attacks described in Patent Literature 1 and Non-Patent Literature 3 are countermeasures against authentication based on features of a body, such as a fingerprint or a face, which are acquired as images. Therefore, countermeasures against spoofing attacks on authentication using a biological signal are not sufficient. In particular, countermeasures against spoofing attacks by illegally measuring a biological signal of an opposite party who intends to spoof are not taken from the viewpoint of authentication.

[0018] An object of the present disclosure is to enable countermeasures against spoofing attacks by illegally measuring a biological signal.

[0019] Means for solving the problem

[0020] The authentication device of the present disclosure includes a signal acquisition unit that acquires a biological signal, an authentication information generation unit that generates authentication information that differs depending on an individual of a living body, based on the biological signal acquired by the signal acquisition unit, a site information generation unit that generates site information that differs depending on a site of acquisition of the biological signal, based on the biological signal, and an authentication unit that performs authentication based on the authentication information generated by the authentication information generation unit and the site information generated by the site information generation unit.

[0021] Effects of the invention

[0022] In the present disclosure, site information is used in addition to authentication information to perform authentication. Thereby, in a case where a biological signal illegally measured at a site other than an intended site is used, it is possible to control so that authentication is not successful. Therefore, it is possible to enable countermeasures against spoofing attacks based on illegal measurement of a biological signal. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a configuration diagram of the authentication device 10 of Embodiment 1.

[0024] Figure 2 is a flowchart of processing of the authentication device 10 of Embodiment 1.

[0025] Figure 3 is an explanatory diagram of site information in a case where the biological signal of Embodiment 1 is an ECG.

[0026] Figure 4 is an explanatory diagram of site information in a case where the biological signal of Embodiment 1 is a PPG.

[0027] Figure 5 is an explanatory diagram of authentication reference information and site reference information of Embodiment 1.

[0028] Figure 6 is a flowchart of processing of the authentication device 10 of Embodiment 2.

[0029] Figure 7 is a configuration diagram of the authentication device 10 of Embodiment 2.

[0030] Figure 8 is a flowchart of the process of the authentication device 10 of Embodiment 2.

[0031] Figure 9 is an explanatory diagram of the composite signal of Embodiment 2.

[0032] Figure 10 is a flowchart of the process of the authentication device 10 of Modified Example 5.

[0033] Figure 11 is a configuration diagram of the authentication device 10 of Embodiment 3.

[0034] Figure 12 is a flowchart of the process of the authentication device 10 of Embodiment 3.

[0035] Figure 13 is an explanatory diagram of the authentication reference information and the site reference information of Embodiment 3.

[0036] Figure 14 is an explanatory diagram of the authentication reference information and the site reference information of Embodiment 3.

[0037] Figure 15 is a flowchart of the process of the authentication device 10 of Modified Example 6.

[0038] Figure 16 is a configuration diagram of the authentication device 10 of Embodiment 4.

[0039] Figure 17 is a flowchart of the process of the authentication device 10 of Embodiment 4.

[0040] Figure 18 is an explanatory diagram of the physiological index of Embodiment 4.

[0041] Figure 19 is an explanatory diagram of the authentication reference information, the site reference information, and the reference value of the physiological index of Embodiment 4.

[0042] Figure 20 is a flowchart of the process of the authentication device 10 of Modified Example 7. DETAILED DESCRIPTION

[0043] Embodiment 1.

[0044] * * * Explanation of Structure * * *

[0045] Reference Figure 1 The structure of the authentication device 10 of Embodiment 1 will be explained.

[0046] The authentication device 10 is a computer. As a specific example, the authentication device 10 is a wearable device such as a smart watch, a mobile device such as a smart phone, and a set-type device provided at an entrance of a building or the like.

[0047] The authentication device 10 is provided with a processor 11, a memory 12, a sensor interface 13, a display interface 14, a communication interface 15, and an auxiliary storage device 16 such hardware. The processor 11 is connected to the other hardware via a signal line, and controls the other hardware.

[0048] The processor 11 is an IC (Integrated Circuit) that performs processing. As a specific example, the processor 11 is a CPU (Central Processing Unit), a DSP (Digital Signal Processor), or a GPU (Graphics Processing Unit).

[0049] The memory 12 is a storage device that temporarily stores data. As a specific example, the memory 12 is an SRAM (Static Random Access Memory) or a DRAM (Dynamic Random Access Memory).

[0050] The sensor interface 13 is an interface for communicating with a sensor 31 mounted on or provided outside the authentication device 10. As a specific example, the sensor interface 13 is a port of a USB (Universal Serial Bus).

[0051] In the Figure 1 In the

[0052] The display interface 14 is an interface for communicating with a display mounted on or provided outside the authentication device 10. As a specific example, the display interface 14 is a port of an HDMI (registered trademark, High-Definition Multimedia Interface).

[0053] The communication interface 15 is an interface for communicating with an external device. As a specific example, the communication interface 15 is a port of Ethernet (registered trademark; Ethernet).

[0054] The auxiliary storage device 16 is a storage device that stores data. As a specific example, the auxiliary storage device 16 is an HDD (Hard Disk Drive). In addition, the auxiliary storage device 16 can also be an SD (registered trademark, Secure Digital) memory card, a CF (CompactFlash: registered trademark), a NAND flash memory, a floppy disk, an optical disk, a Blu-ray (registered trademark) optical disk, a DVD (Digital Versatile Disk), such a removable recording medium.

[0055] As functional structural elements, the authentication device 10 is provided with a signal acquisition section 21, an authentication information generation section 22, a position information generation section 23, and an authentication section 24. The functions of each of the functional structural elements of the authentication device 10 are realized by software.

[0056] A program that realizes the functions of each of the functional structural elements of the authentication device 10 is stored in the auxiliary storage device 16. The program is read into the memory 12 by the processor 11 and executed by the processor 11. By this, the functions of each of the functional structural elements of the authentication device 10 are realized.

[0057] In Figure 1 In

[0058] * * * Explanation of Action * * *

[0059] The action of the authentication device 10 of Embodiment 1 will be explained. Figures 2 to 5 The action of the authentication device 10 of Embodiment 1 will be explained.

[0060] The action steps of the authentication device 10 of Embodiment 1 correspond to the authentication method of Embodiment 1. In addition, the program that realizes the action of the authentication device 10 of Embodiment 1 corresponds to the authentication program of Embodiment 1.

[0061] The action of the authentication device 10 of Embodiment 1 will be explained. Figure 2 The processing flow of the authentication device 10 of Embodiment 1 will be explained.

[0062] (Step S101: Signal acquisition processing)

[0063] The signal acquisition unit 21 acquires a biological signal of the subject from the sensor 31 connected via the sensor interface 13. As a specific example, consider a time series signal such as an ECG obtained by measurement of electrical activity of the heart, and a PPG obtained by optically measuring behavior of blood vessels accompanying a heartbeat. However, the biological signal is not limited thereto. The signal acquisition unit 21 can also write the biological signal into the memory 12.

[0064] (Step S102: authentication information generation processing)

[0065] The authentication information generation unit 22 generates authentication information that differs according to the individual of the living body, based on the biological signal acquired in step S101.

[0066] Specifically, the authentication information generation unit 22 reads out the biological signal from the memory 12. The authentication information generation unit 22 generates a waveform of the biological signal as the authentication information, or generates the authentication information by extracting a feature quantity from the biological signal and taking the feature quantity as the authentication information. The method of generating the authentication information is not limited as long as the authentication information differs according to the individual of the living body. The authentication information generation unit 22 writes the authentication information into the memory 12.

[0067] (Step S103: site information generation processing)

[0068] The site information generation unit 23 generates site information that differs according to the site of acquisition of the biological signal even for the same individual, based on the biological signal acquired in step S101.

[0069] Specifically, the site information generation unit 23 reads out the biological signal from the memory 12. The site information generation unit 23 generates the site information by generating a waveform of the biological signal as the site information, or extracting a feature quantity from the biological signal and taking the feature quantity as the site information, as with the method of generating the authentication information. However, the site information needs to be information that differs according to the site of acquisition of the biological signal. The method of generating the site information is not limited as long as the site information differs according to the site of acquisition of the biological signal. The site information generation unit 23 writes the site information into the memory 12.

[0070] Reference Figure 3 An example of the site information in the case where the biological signal is an ECG is described.

[0071] In Figure 3 , an example in which waveforms of ECGs measured at a plurality of sites are compared in superposition is shown. Specifically, in Figure 3 , waveforms of ECGs measured at the wrist and waveforms of ECGs measured at the palm are shown for the same individual. As Figure 3As shown, it is known that even for the same individual, the maximum value and the timing at which the maximum value appears deviate. Therefore, it is considered that the maximum value and the timing at which the maximum value appears in the waveform of the ECG are used as the site information.

[0072] Referring to Figure 4 , an example of the site information in the case of the biological signal being the PPG is described.

[0073] In Figure 4 , an example in which the waveforms of the PPG measured at a plurality of sites are compared in superposition is shown. Specifically, in Figure 4 , the waveform of the PPG measured at a finger and the waveform of the PPG measured at the forehead are shown for the same individual. As Figure 4 shown, it is known that even for the same individual, the timing at which the first maximum value appears and the second maximum value deviate. Therefore, it is considered that the maximum value and the timing at which the maximum value appears in the waveform of the PPG are used as the site information.

[0074] (Step S104: 1st authentication processing)

[0075] The authentication section 24 compares the authentication information generated in step S102 with the authentication reference information stored in advance in the auxiliary storage device 16, and determines whether the 1st authentication is successful or failed.

[0076] Specifically, the authentication section 24 determines whether the condition that the degree of similarity of the authentication information generated in step S102 and the authentication reference information is above the 1st threshold value or the difference between the authentication information generated in step S102 and the authentication reference information is within the allowable value is satisfied. The authentication section 24 determines that the 1st authentication is successful in the case where the condition is satisfied, and determines that the 1st authentication is failed in the case where the condition is not satisfied.

[0077] The authentication section 24 causes the processing to proceed to step S105 in the case where it is determined that the 1st authentication is successful. On the other hand, the authentication section 24 ends the processing with the authentication being failed in the case where it is determined that the 1st authentication is failed. In addition, in the case where it is determined that the 1st authentication is failed, the processing can be returned to step S101, and the authentication processing can be performed again.

[0078] (Step S105: 2nd authentication processing)

[0079] The authentication section 24 compares the site information generated in step S103 with the site reference information stored in advance in the auxiliary storage device 16, and determines whether the 2nd authentication is successful or failed.

[0080] Specifically, the authentication section 24 determines whether the condition that the degree of similarity of the part information generated in step S103 to the part reference information is equal to or greater than the second threshold value or the difference between the part information generated in step S103 and the part reference information is within the allowable value is satisfied. The authentication section 24 determines that the second authentication is successful in the case where the condition is satisfied, and determines that the second authentication is failed in the case where the condition is not satisfied.

[0081] The authentication section 24 ends the process with the authentication being successful in the case where it is determined that the second authentication is successful. On the other hand, the authentication section 24 ends the process with the authentication being failed in the case where it is determined that the second authentication is failed. In addition, in the case where it is determined that the second authentication is failed, the process can be returned to step S101 and the authentication process can be performed again.

[0082] In step S104, it is explained that the authentication reference information is stored in the auxiliary storage device 16 in advance. Further, in step S105, it is explained that the part reference information is stored in the auxiliary storage device 16 in advance.

[0083] In this way, as a premise of the process shown in Figure 2 , it is necessary to store the authentication reference information and the part reference information in advance. Specifically, the process of steps S101 to S103 is executed, the authentication information generated in step S102 is stored as the authentication reference information, and the part information generated in step S103 is stored as the part reference information.

[0084] The authentication information and the part information sometimes change as the years pass. Thus, the authentication reference information and the part reference information can be newly acquired in the case where a certain period has passed. Further, as shown in Figure 5 , the authentication reference information and the part reference information are stored together with the measurement date and time of the biological signal for one subject. In addition, in Figure 5 , a case where a feature amount is used as the authentication reference information and the part reference information is shown.

[0085] In addition, the execution order of steps S102 and S103 and the execution order of steps S104 and S105 are not limited to the order shown in Figure 2 , and can be changed.

[0086] Effects of Embodiment 1

[0087] As described above, the authentication device 10 of Embodiment 1 performs authentication using the part information in addition to the authentication information. Thereby, in the case where the biological signal illegally measured at a part other than the intended part is used, it is possible to control so that the authentication is not successful. Thus, it is possible to realize a countermeasure against a spoofing attack based on illegal measurement of the biological signal.

[0088] Other configurations

[0089]

[0090] The number of sensors 31 is not particularly limited. The authentication information and the part information can be generated based on a single biological signal measured by a single sensor, or the authentication information and the part information can be generated based on a plurality of biological signals measured by a plurality of sensors.

[0091] Further, the signal acquisition unit 21 can also control the sensors 31 via the sensor interface 13, and switchably acquire the biological signals for generating the authentication information and the biological signals for generating the part information. For example, the signal acquisition unit 21 considers the sensor 31 used for switching, or the set value required for changing the operation of the sensor 31. In this case, the authentication information generation unit 22 generates the authentication information based on the biological signals for generating the authentication information, and the part information generation unit 23 generates the part information based on the biological signals for generating the part information.

[0092]

[0093] In Embodiment 1, if the first authentication based on the authentication information and the second authentication based on the part information are successful once, the authentication is successful. However, the authentication can be successful in a case where the first authentication based on the authentication information and the second authentication based on the part information are continuously successful a plurality of times.

[0094] Reference Figure 6 The processing flow of the authentication device 10 of the modified example 2 will be described.

[0095] The processing of steps S111 to S115 is the same as that of steps S101 to S105 of Embodiment 1. Figure 2 However, in step S115, the authentication unit 24 causes the processing to proceed to step S116 in a case where it is determined that the second authentication is successful.

[0096] (Step S116: continuation determination processing)

[0097] The authentication unit 24 determines whether the number of successful times of the first authentication and the second authentication reaches a reference number.

[0098] The authentication unit 24 ends the processing with the authentication being successful in a case where the number of successful times reaches the reference number. On the other hand, the authentication unit 24 returns the processing to step S111 in a case where the number of successful times does not reach the reference number.

[0099] ​​Further, in step S115 after the second time, the authentication section 24 can also determine whether the position information is position information about the same position as the position information generated the first time. Then, the authentication section 24 can also determine that the second authentication is successful in a case where the conditions are satisfied and the position information is position information about the same position as the position information generated the first time.

[0100] Thus, in a case where the measurement position is changed in the middle of the process, authentication can also fail. That is, in a case where the sensor is moved in the middle of the process, authentication can also fail.

[0101] <Modification example 3>

[0102] In Embodiment 1, each functional structural element is realized by software. However, as a modification example 3, each functional structural element can also be realized by hardware. Regarding this modification example 3, points different from Embodiment 1 will be described.

[0103] The structure of the authentication device 10 of the modification example 3 will be described.

[0104] In a case where each functional structural element is realized by hardware, the authentication device 10 is provided with an electronic circuit instead of the processor 11, the memory 12, and the auxiliary storage device 16. The electronic circuit is a dedicated circuit that realizes the functions of each functional structural element, the memory 12, and the auxiliary storage device 16.

[0105] As the electronic circuit, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, a logic IC, a GA (Gate Array), an ASIC (Application Specific Integrated Circuit), and a FPGA (Field-Programmable Gate Array) are assumed.

[0106] Each functional structural element can be realized by one electronic circuit, or each functional structural element can be realized by being dispersed into a plurality of electronic circuits.

[0107] <Modification example 4>

[0108] As a modification example 4, part of each functional structural element can be realized by hardware, and the other each functional structural element can be realized by software.

[0109] The processor 11, the memory 12, the auxiliary storage device 16, and the electronic circuit are referred to as processing circuits. That is, the functions of each functional structural element are realized by the processing circuits.

[0110] Embodiment 2.

[0111] The difference between Embodiment 2 and Embodiment 1 is that at least one of authentication information and location information is generated based on the composite signal, which is generated by processing multiple biological signals obtained from multiple sensors 31 as input. In Embodiment 2, this difference will be explained, while the similarities will be omitted.

[0112] In Implementation 2, the situation of generating both authentication information and location information based on the composite signal is described.

[0113] ***Structure Explanation***

[0114] Reference Figure 7 The structure of the authentication device 10 in Embodiment 2 will be described.

[0115] The authentication device 10 has a signal processing unit 25 as a functional structural element, which is similar to... Figure 1 The authentication device 10 shown is different. The signal processing unit 25, like other functional structural elements, is implemented in software or hardware.

[0116] Furthermore, the authentication device 10 connects the processor 11 to multiple sensors 31 via the sensor interface 13. Figure 1 The authentication device 10 shown is different. Each sensor 31 can be a sensor of the same specification or a sensor of different specifications.

[0117] ***Instructions for the Actions***

[0118] Reference Figure 8 and Figure 9 The operation of the authentication device 10 in Embodiment 2 will be explained.

[0119] The operation steps of the authentication device 10 in Embodiment 2 are equivalent to the authentication method in Embodiment 2. Furthermore, the program for implementing the operation of the authentication device 10 in Embodiment 2 is equivalent to the authentication program in Embodiment 2.

[0120] Reference Figure 8 The processing flow of the authentication device 10 in Embodiment 2 will be described.

[0121] Processing in steps S206 to S207 Figure 2 The processing of steps S104 to S105 is the same.

[0122] (Step S201: Calculation method determination and processing)

[0123] The signal processing unit 25 determines the processing method for processing the composite signal. As a specific example, the processing method is the addition or subtraction of signals from multiple organisms. However, the processing method is not limited to this.

[0124] Specifically, the signal operation section 25 determines the operation method by accepting an operation method designation from the subject or the like, or by reading out a previously set operation method.

[0125] (Step S202: Signal acquisition processing)

[0126] The signal acquisition section 21 acquires a plurality of biological signals of the subject from a plurality of sensors 31 connected via the sensor interface 13. The signal acquisition section 21 writes the plurality of biological signals in the memory 12.

[0127] (Step S203: Signal operation processing)

[0128] The signal operation section 25 generates a composite signal by operating the plurality of biological signals acquired in step S202 as input by the operation method determined in step S201. The signal operation section 25 writes the composite signal in the memory 12.

[0129] Reference Figure 9 Examples of the composite signal will be described.

[0130] In Figure 9 , an example in which PPG is measured by two sensors 31 and operation of the obtained PPGs with each other is performed is shown. PPG is measured by acquiring reflected light or transmitted light obtained by irradiating light from a light source to a blood vessel by a light receiving section. The measured waveform of PPG differs depending on the wavelength (color) of the light source. In particular, the depth to which light can reach in a living body differs depending on the wavelength. Therefore, for example, as shown in Figure 9 , it is considered that by calculating the difference between a biological signal obtained by green light and a biological signal obtained by infrared light, only deep information can be extracted. It is considered that the composite signal obtained by such operation between each biological signal is difficult to artificially generate compared to a single biological signal.

[0131] (Step S204: Authentication information generation processing)

[0132] The authentication information generation section 22 generates authentication information from the composite signal generated in step S203. The generation method of the authentication information is the same as in Embodiment 1 except that the composite signal is input instead of the biological signal. The authentication information generation section 22 writes the authentication information in the memory 12.

[0133] (Step S205: Region information generation processing)

[0134] The part information generation section 23 generates part information based on the composite signal generated in step S203. The method of generating the part information is the same as in Embodiment 1 except that the composite signal is used as input instead of the biological signal. The part information generation section 23 writes the part information into the memory 12.

[0135] As a prerequisite for the processing shown in Figure 8 In order to perform the processing shown in

[0136] In addition, the order of execution of step S204 and step S205 and the order of execution of step S206 and step S207 are not limited to Figure 8 the order shown in

[0137] Effects of Embodiment 2

[0138] As described above, the authentication device 10 of Embodiment 2 generates at least either the authentication information or the part information based on a composite signal obtained by operating a plurality of biological signals. It is believed that the composite signal is difficult to generate artificially compared to a single biological signal. Therefore, a better countermeasure against spoofing attacks for illegal measurement based on biological signals can be achieved.

[0139] Other Structures

[0140] <Variant Example 5>

[0141] As in Variant Example 2, the authentication can be successful when the first authentication based on the authentication information and the second authentication based on the part information are successful consecutively a plurality of times.

[0142] Reference Signs Figure 10 The processing flow of the authentication device 10 of Variant Example 5 will be described.

[0143] The processing of step S211 to step S217 is the same as the processing of step S201 to step S207 of Figure 8 However, in step S217, the authentication section 24 causes the processing to proceed to step S218 when it is determined that the second authentication is successful.

[0144] (Step S218: Continue Determination Processing)

[0145] The authentication section 24 determines whether the number of successes of the first authentication and the second authentication reaches a reference number.

[0146] The authentication section 24 ends the processing with success of the authentication in a case where the number of successes reaches the reference number. On the other hand, the authentication section 24 returns the processing to step S211 in a case where the number of successes does not reach the reference number.

[0147] In addition, as in Modification 2, in step S217 after the second time, the authentication section 24 can determine whether the position information is position information about the same position as the position information generated at the first time. Then, the authentication section 24 can determine that the second authentication is successful in a case where the condition is satisfied and the position information is position information about the same position as the position information generated at the first time.

[0148] Further, in step S211, the operation method can be changed each time so that observation from an attacker is not possible, and the composite signal can be generated by a different operation method each time. Thereby, the difficulty of the spoofing attack can be further improved.

[0149] Embodiment 3.

[0150] Embodiment 3 differs from Embodiment 1 in that the biological signal corresponding to the sensor control information is acquired by acquiring the biological signal on the basis of the sensor control information provided to the sensor 31. In Embodiment 3, the difference is described, and the description of the same points is omitted.

[0151] * * * Description of Structure * * *

[0152] Reference Figure 11 The structure of the authentication device 10 of Embodiment 3 is described.

[0153] The authentication device 10 differs from the authentication device 10 shown in Embodiment 1 in that the processor 11 is connected to a plurality of sensors 31 via the sensor interface 13. Each sensor 31 is controlled by the sensor control information provided from the processor 11. Figure 1

[0154] In addition, here, a case where a plurality of sensors 31 is used is described, but the authentication device 10 can use a single sensor 31 to acquire the biological signal different according to the sensor control information.

[0155] * * * Description of Action * * *

[0156] Reference Figures 12 to 14 The action of the authentication device 10 of Embodiment 3 is described.

[0157] ​The operation steps of the authentication device 10 of Embodiment 3 correspond to the authentication method of Embodiment 3. Furthermore, a program that realizes the operation of the authentication device 10 of Embodiment 3 corresponds to the authentication program of Embodiment 3.

[0158] Referring to Figure 12 The processing flow of the authentication device 10 of Embodiment 3 will be described.

[0159] The processing of steps S303 to S304 is the same as that of steps S102 to S103 of Figure 2

[0160] (Step S301: Control information decision processing)

[0161] The signal acquisition section 21 decides sensor control information. As a specific example, the sensor control information is information indicating which of the plurality of sensors 31 is used, and setting information of the wavelength (color) of the light source included in the optical sensor. However, the sensor control information is not limited thereto.

[0162] Specifically, the signal acquisition section 21 decides the sensor control information by accepting designation of the sensor control information from the subject or the like, or reading out sensor control information that is set in advance. As a method of setting in advance, it is considered that the sensor control information to be used is decided in advance according to the time. For example, it is considered that the decision method of using a green light source before time tl and using an infrared light source after time tl. Furthermore, it is considered that the order of use of the control information is decided randomly in advance. For example, it is considered that the decision method of alternately using a green light source and a red light source.

[0163] (Step S302: Signal acquisition processing)

[0164] The signal acquisition section 21 acquires a biological signal corresponding to the sensor control information decided in step S301 from the sensor 31 connected via the sensor interface 13.

[0165] Specifically, the signal acquisition section 21 acquires a biological signal from the sensor 31 on the basis that the sensor 31 is controlled by the sensor control information decided in step S301. The signal acquisition section 21 writes the biological signal in the memory 12.

[0166] (Step S305: 1st authentication processing)

[0167] The authentication section 24 performs 1st authentication using a reference corresponding to the sensor control information decided in step S301.

[0168] ​Specifically, the authentication unit 24 compares the authentication information generated in step S303 with the authentication benchmark information stored in the auxiliary storage device 16 beforehand and corresponding to the sensor control information to determine whether the first authentication is successful or unsuccessful. At this time, the authentication unit 24 determines whether the first authentication is successful or unsuccessful by determining whether the conditions corresponding to the sensor control information are met.

[0169] If the authentication unit 24 determines that the first authentication is successful, the process proceeds to step S306. Conversely, if the authentication unit 24 determines that the first authentication has failed, it sets the process as an authentication failure and ends the process. Alternatively, if the first authentication has failed, the process can be returned to step S301 to re-perform the authentication process.

[0170] (Step S306: Second Authentication Process)

[0171] The certification unit 24 performs the second certification using a reference corresponding to the sensor control information determined in step S301.

[0172] Specifically, the authentication unit 24 compares the location information generated in step S304 with the location reference information pre-stored in the auxiliary storage device 16 and corresponding to the sensor control information to determine whether the second authentication is successful or unsuccessful. At this time, the authentication unit 24 determines whether the second authentication is successful or unsuccessful by determining whether the conditions corresponding to the sensor control information are met.

[0173] If the authentication unit 24 determines that the second authentication is successful, it sets the authentication as successful and ends the process. On the other hand, if the authentication unit 24 determines that the second authentication has failed, it sets the authentication as failed and ends the process. Alternatively, if the second authentication is determined to have failed, the process can be returned to step S301 to re-perform the authentication process.

[0174] As a result of Figure 12 The processing described requires pre-storing authentication benchmark information and location benchmark information corresponding to the sensor control information. Specifically, steps S301 to S304 are executed, storing the authentication information generated in step S303 as authentication benchmark information and the location information generated in step S304 as location benchmark information. At this time, for each sensor control information used, steps S301 to S304 are executed, storing the authentication benchmark information and location benchmark information corresponding to each sensor control information.

[0175] The result is, as Figure 13 and Figure 14 As shown, for a single subject, authentication reference information and site reference information are stored together with the measurement date and time of the biological signal, according to the control information of each sensor. Figure 13An example of a case where the sensor 31 to be used is changed in accordance with the sensor control information is shown. Figure 14 An example of a case where the light source is changed in accordance with the sensor control information is shown. In addition, in Figure 13 and Figure 14 , a case where the feature amount is used as the authentication reference information and the part reference information is shown. In Figure 13 , the authentication reference information and the part reference information of a case where the sensor 1 is used and a case where the sensor 2 is used are stored for each subject. In Figure 14 , the authentication reference information and the part reference information of a case where the light source is set to green and a case where the light source is set to red are stored for each subject.

[0176] In addition, the execution order of the step S303 and the step S304 and the execution order of the step S305 and the step S306 are not limited to the order shown in Figure 12 , and can be changed.

[0177] * * * Effect of Embodiment 3 * * *

[0178] As described above, the authentication device 10 of Embodiment 3 acquires the biological signal corresponding to the sensor control information. For example, the PPG is measured by using the light source such as green and infrared light together with the light detector, but the waveform measured differs depending on the wavelength of the light source. Therefore, by changing the wavelength of the light source, different information is obtained as the authentication information and the part information. The attacker cannot observe the sensor control information. For example, the attacker cannot observe the kind of the light source used as the control information or the sensor 31 to be used. Therefore, it is not possible to realize a spoofing attack based on the measurement or generation of the biological signal for authentication, or the difficulty level is higher compared to the case of Embodiment 1.

[0179] * * * Other Structures * * *

[0180] < Modification Example 6 >

[0181] Also in the case where the first authentication based on the authentication information and the second authentication based on the part information are continuously successful a plurality of times, the authentication can be successful.

[0182] Referring to Figure 15 , the processing flow of the authentication device 10 of Modification Example 6 will be described.

[0183] The processing of the step S311 to the step S316 is the same as the processing of the step S301 to the step S306 of Figure 12 . However, in the step S316, the authentication unit 24 causes the processing to proceed to the step S317 in the case where it is determined that the second authentication is successful.

[0184] (Step S317: Continue the judgment and processing)

[0185] The certification department 24 determines whether the number of successful certifications for the first and second certifications has reached the benchmark number.

[0186] If the number of successful authentications reaches a certain threshold, the authentication unit 24 marks the authentication as successful and terminates the process. Conversely, if the number of successful authentications does not reach the threshold, the authentication unit 24 returns the process to step S311.

[0187] Alternatively, similar to Variation 2, in step S316 after the second time, the authentication unit 24 may determine whether the part information pertains to the same part as the part information generated in the first time. Then, the authentication unit 24 may determine that the second authentication is successful if the conditions are met and the part information pertains to the same part as the part information generated in the first time.

[0188] Furthermore, in step S311, the sensor control information can be changed each time. This further increases the difficulty of deception attacks.

[0189] Implementation method 4.

[0190] The difference between Embodiment 4 and Embodiment 1 lies in the use of physiological indicators such as heart rate and respiratory rate for verification, which are determined using multiple methods, including optical and electrical methods. Embodiment 4 explains this difference, omitting explanations of the similarities.

[0191] ***Structure Explanation***

[0192] Reference Figure 16 The structure of the authentication device 10 in Embodiment 4 will be described.

[0193] The authentication device 10 has a physiological indicator generation unit 26 as a functional structural element, which is similar to... Figure 1 The authentication device 10 shown is different. The physiological indicator generation unit 26, like other functional structural elements, is implemented by software or hardware.

[0194] Furthermore, the authentication device 10 connects the processor 11 to multiple sensors 31 via the sensor interface 13. Figure 1 The authentication device 10 shown is different. As multiple sensors 31, sensors such as optical sensors and vibration sensors are used to measure different physical quantities.

[0195] ***Instructions for the Actions***

[0196] Reference Figures 17 to 19 The operation of the authentication device 10 in Embodiment 4 will be explained.

[0197] The operation steps of the authentication device 10 of Embodiment 4 correspond to the authentication method of Embodiment 4. Further, a program realizing the operation of the authentication device 10 of Embodiment 4 corresponds to the authentication program of Embodiment 4.

[0198] Reference Figure 17 The processing flow of the authentication device 10 of Embodiment 4 will be described.

[0199] The processing of steps S402 to S403 is the same as that of steps S102 to S103 of Embodiment 1. The processing of steps S405 to S406 is the same as that of steps S104 to S105 of Embodiment 1. Figure 2 The processing of steps S405 to S406 is the same as that of steps S104 to S105 of Embodiment 1. However, in step S406, in a case where it is determined that the second authentication is successful, the processing proceeds to step S407 without being regarded as the authentication is successful. Figure 2 The processing of steps S405 to S406 is the same as that of steps S104 to S105 of Embodiment 1. However, in step S406, in a case where it is determined that the second authentication is successful, the processing proceeds to step S407 without being regarded as the authentication is successful.

[0200] (Step S401: Signal acquisition processing)

[0201] The signal acquisition unit 21 acquires a plurality of biological signals of the subject from a plurality of sensors 31 connected via the sensor interface 13. The signal acquisition unit 21 writes the plurality of biological signals in the memory 12.

[0202] Here, although a plurality of biological signals are acquired, in step S402, authentication information can be generated from any one of the biological signals, or authentication information can be generated from a plurality of biological signals. Similarly, in step S403, site information can be generated from any one of the biological signals, or site information can be generated from a plurality of biological signals. In addition, authentication information and site information can be generated using other biological signals.

[0203] (Step S404: Physiological index generation processing)

[0204] The physiological index generation unit 26 generates physiological indices related to the same physiology from the plurality of biological signals acquired in step S401, respectively. The physiological index generation unit 26 writes the physiological indices generated from the respective biological signals in the memory 12.

[0205] Reference Figure 18 Examples of the physiological indices will be described.

[0206] In Figure 19In this process, the PPG of the subject is measured by a PPG measuring sensor, and minute vibrations of the subject are measured by a vibration measuring sensor such as a piezoelectric element. It is known that physiological indicators such as heart rate and respiratory rate can be obtained from PPG. It is also known that physiological indicators such as heart rate and respiratory rate can be obtained from minute vibrations obtained by the vibration measuring sensor. Therefore, the physiological indicator generation unit 26 considers, for example, generating heart rate as a physiological indicator based on both PPG and minute vibrations.

[0207] (Step S407: Third Authentication Process)

[0208] The certification department 24 compares the physiological indicators generated from signals from multiple organisms to determine whether the third certification is successful or unsuccessful.

[0209] Specifically, the authentication unit 24 determines whether the following conditions are met: the similarity of physiological indicators generated from multiple biological signals is above the third threshold, or the difference between physiological indicators generated from multiple biological signals is within an acceptable value. If the conditions are met, the authentication unit 24 determines that the third authentication is successful; if the conditions are not met, the third authentication is deemed unsuccessful.

[0210] If the authentication unit 24 determines that the third authentication is successful, it sets the authentication as successful and ends the process. On the other hand, if the authentication unit 24 determines that the third authentication has failed, it sets the authentication as failed and ends the process. Alternatively, if the third authentication has failed, the process can be returned to step S401 to re-perform the authentication process.

[0211] Additionally, as a condition for determining whether the third certification is successful or unsuccessful, it may also include whether the difference between the physiological indicators generated from multiple biological signals and the baseline values ​​of those physiological indicators is within an acceptable range. In this case, such as Figure 17 As shown, as a process Figure 17 The processing described requires, in addition to authentication and site baseline information, the baseline values ​​of physiological indicators to be stored in advance. Specifically, when performing steps S401 to S404, the average value of the physiological indicators generated in step S404 is stored as the baseline value of the physiological indicators.

[0212] Furthermore, the execution order of steps S402 to S404 and the execution order of steps S405 to S407 are not limited to [specific steps]. Figure 20 The order shown can also be changed.

[0213] ***Effects of Implementation Method 4***

[0214] As above, the authentication device 10 of Embodiment 4 performs authentication using the physiological index in addition to the authentication information and the part information. Thereby, it is possible to somewhat ensure that the measured subject is a living body. Further, since different physical quantities are measured by the plurality of sensors 31, the effort and the difficulty of generating an artificial signal become high, as a result, the difficulty of a spoof attack becomes high.

[0215] Other configurations

[0216] <Variant 7>

[0217] Also, as in Variant 2, in a case where the first authentication based on the authentication information, the second authentication based on the part information, and the third authentication based on the physiological index are continuously successful a plurality of times, the authentication is made successful.

[0218] Reference Figure 17 The processing flow of the authentication device 10 of Variant 7 will be described.

[0219] The processing of steps S411 to S417 is the same as that of steps S401 to S407 of Embodiment 1. However, in step S417, the authentication section 24, in a case where it is determined that the third authentication is successful, causes the processing to proceed to step S418. ​

[0220] (Step S418: continuation determination processing)

[0221] The authentication section 24 determines whether the number of successes of the first authentication, the second authentication, and the third authentication reaches a reference number.

[0222] The authentication section 24, in a case where the number of successes reaches the reference number, makes the authentication successful and ends the processing. On the other hand, the authentication section 24, in a case where the number of successes does not reach the reference number, returns the processing to step S411.

[0223] Also, as in Variant 2, in step S416 after the second time, the authentication section 24 can determine whether the part information is part information about the same part as the part information generated at the first time. Then, the authentication section 24 can determine that the second authentication is successful in a case where the condition is satisfied and the part information is part information about the same part as the part information generated at the first time.

[0224] Also, "unit" in the above description can be rewritten as "circuit", "step", "step", "processing", or "processing circuit".

[0225] ​The above describes embodiments and modifications of the present disclosure. Any of these embodiments and modifications can be combined and implemented. Furthermore, any one or several of these embodiments and modifications can be implemented in part. In addition, the present disclosure is not limited to the above embodiments and modifications, and various changes can be made as needed.

[0226] Legend of reference signs

[0227] 10 authentication device, 11 processor, 12 memory, 13 sensor interface, 14 display interface, 15 communication interface, 16 auxiliary storage device, 21 signal acquisition unit, 22 authentication information generation unit, 23 site information generation unit, 24 authentication unit, 25 signal operation unit, 26 physiological index generation unit, 31 sensor.

Claims

1. An authentication device, wherein the authentication device includes: a signal acquisition unit that acquires a plurality of biological signals different according to individuality of a living body a plurality of times with time lags; a signal operation unit that generates a composite signal by operating the plurality of biological signals different according to individuality of a living body acquired a plurality of times by the signal acquisition unit by respective different operation methods at each acquisition; an authentication information generation unit that generates authentication information different according to individuality of a living body from the composite signal generated by the signal operation unit; a site information generation unit that generates site information different according to an acquisition site of a biological signal from at least any one of the biological signals acquired by the signal acquisition unit; and an authentication unit that performs authentication based on the authentication information generated by the authentication information generation unit and the site information generated by the site information generation unit. 2.An authentication device, wherein the authentication device includes: a signal acquisition unit that acquires a plurality of biological signals different according to individuality of a living body a plurality of times with time lags; a signal operation unit that generates a composite signal by operating the plurality of biological signals different according to individuality of a living body acquired a plurality of times by the signal acquisition unit by respective different operation methods at each acquisition; an authentication information generation unit that generates authentication information different according to individuality of a living body from at least any one of the biological signals acquired by the signal acquisition unit; a site information generation unit that generates site information different according to an acquisition site of a biological signal from the composite signal generated by the signal operation unit; and an authentication unit that performs authentication based on the authentication information generated by the authentication information generation unit and the site information generated by the site information generation unit. 3.An authentication device, wherein the authentication device includes: a signal acquisition unit that acquires biological signals corresponding to sensor control information different according to each time a plurality of times with time lags; an authentication information generation unit that generates authentication information different according to individuality of a living body from biological signals each of which is the object of the biological signals acquired a plurality of times by the signal acquisition unit; a site information generation unit that generates site information different according to an acquisition site of a biological signal from biological signals each of which is the object of the biological signals acquired a plurality of times; an authentication unit that performs authentication using a reference corresponding to the sensor control information corresponding to the object biological signal, based on the authentication information generated by the authentication information generation unit with respect to the object biological signal, and the site information generated by the site information generation unit with respect to the object biological signal, with the biological signal each of which is the object of the biological signals acquired a plurality of times. 4.The authentication device according to any one of claims 1 to 3, wherein the authentication unit determines whether authentication is successful or not according to whether the authentication information satisfies a reference and the site information satisfies a reference or not. ​ ​ 5. The authentication device according to claim 4, wherein the part information generation section generates the part information for each of the plurality of times of acquisition of the biological signal, the authentication section determines whether or not authentication is successful based on whether or not the part information related to each of the plurality of times of acquisition of the biological signal is part information about the same part.

6. The authentication device according to any one of claims 1 to 3, wherein the authentication device further comprises a physiological index generation section that generates a physiological index related to the same physiology based on the two or more biological signals acquired by the signal acquisition section, the authentication section performs authentication by comparing the physiological index generated by the physiological index generation section based on the two or more biological signals.

7. The authentication device according to claim 4, wherein the authentication device further comprises a physiological index generation section that generates a physiological index related to the same physiology based on the two or more biological signals acquired by the signal acquisition section, the authentication section performs authentication by comparing the physiological index generated by the physiological index generation section based on the two or more biological signals.

8. The authentication device according to claim 5, wherein the authentication device further comprises a physiological index generation section that generates a physiological index related to the same physiology based on the two or more biological signals acquired by the signal acquisition section, the authentication section performs authentication by comparing the physiological index generated by the physiological index generation section based on the two or more biological signals.

9. An authentication method, wherein a signal acquisition section acquires a plurality of biological signals that differ according to the individual of a living body a plurality of times with the timing offset, a signal operation section generates a composite signal by operating each of the plurality of biological signals that differ according to the individual of a living body a plurality of times by a different operation method each time it is acquired, an authentication information generation section generates authentication information that differs according to the individual of a living body based on the composite signal, a part information generation section generates part information that differs according to the part at which the biological signal is acquired based on at least any one of the biological signals, an authentication section performs authentication based on the authentication information and the part information.

10. An authentication method, wherein a signal acquisition section acquires a plurality of biological signals that differ according to the individual of a living body a plurality of times with the timing offset, a signal operation section generates a composite signal by operating each of the plurality of biological signals that differ according to the individual of a living body a plurality of times by a different operation method each time it is acquired, an authentication information generation section generates authentication information that differs according to the individual of a living body based on at least any one of the biological signals, a part information generation section generates part information that differs according to the part at which the biological signal is acquired based on the composite signal, an authentication section performs authentication based on the authentication information and the part information.

11. An authentication method, wherein The signal acquisition unit acquires the biological signals corresponding to the sensor control information different for each time at different times, The authentication information generation unit generates authentication information different for each individual of the living body, based on the biological signals acquired by the signal acquisition unit, The position information generation unit generates position information different for each acquisition position of the biological signals, based on the biological signals acquired by the signal acquisition unit; The authentication unit performs authentication, based on the authentication information generated for the biological signals and the position information generated for the biological signals, using a reference corresponding to the sensor control information corresponding to the biological signals, with the biological signals as the subjects.

12. A computer-readable storage medium storing an authentication program that causes a computer to function as an authentication device, The authentication device performs the following processing: A signal acquisition process that acquires a plurality of biological signals different for each individual of the living body at different times; A signal operation process that generates a composite signal by performing an operation method different for each acquisition time on the plurality of biological signals different for each individual of the living body acquired by the signal acquisition process; An authentication information generation process that generates authentication information different for each individual of the living body, based on the composite signal generated by the signal operation process; A position information generation process that generates position information different for each acquisition position of the biological signals, based on at least any one of the biological signals acquired by the signal acquisition process; and An authentication process that performs authentication based on the authentication information generated by the authentication information generation process and the position information generated by the position information generation process.

13. A computer-readable storage medium storing an authentication program that causes a computer to function as an authentication device, The authentication device performs the following processing: A signal acquisition process that acquires a plurality of biological signals different for each individual of the living body at different times; A signal operation process that generates a composite signal by performing an operation method different for each acquisition time on the plurality of biological signals different for each individual of the living body acquired by the signal acquisition process; An authentication information generation process that generates authentication information different for each individual of the living body, based on at least any one of the biological signals acquired by the signal acquisition process; A position information generation process that generates position information different for each acquisition position of the biological signals, based on the composite signal generated by the signal operation process; and An authentication process that performs authentication based on the authentication information generated by the authentication information generation process and the position information generated by the position information generation process. ​ ​ 14. A computer-readable storage medium storing an authentication program that causes a computer to function as an authentication apparatus, the authentication apparatus performs the following processes: a signal acquisition process of acquiring a biological signal corresponding to sensor control information that differs for each time at a plurality of times at different times; an authentication information generation process of generating authentication information that differs for individuals of a biological body, based on biological signals that are targets of the biological signals acquired at the plurality of times by the signal acquisition process, respectively; a part information generation process of generating part information that differs for acquisition parts of the biological signals, based on the biological signals that are targets of the biological signals acquired at the plurality of times, respectively; an authentication process of performing authentication using a reference corresponding to the sensor control information corresponding to the biological signals that are targets of the biological signals acquired at the plurality of times, based on the authentication information generated for the biological signals that are targets of the biological signals by the authentication information generation process, and the part information generated for the biological signals that are targets of the biological signals by the part information generation process.

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