JP2008158627A - Personal identification device and personal identification method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for improving convenience by saving time and labor of a problem when personal identification rejection is occurred without damaging safety in biometrics. <P>SOLUTION: This personal identification device using authentication by a password and biometrics achieves a system having convenience while keeping a security level by changing a threshold in biometrics according to the security level of password authentication. At first, personal identification is carried out by the password, and the threshold of biometrics is determined according to the security level of the authenticated password. Then, biometrics is carried out, and when similarity with registered information is larger than the threshold, the user is identified as the person in question, and permitted to use equipment or the like. When the similarity is not more than the threshold, the password whose security level is high is input again, and the threshold in biometrics is changed so that personal identification can be simplified. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a security technique for limiting users in an information device or service, and relates to a personal authentication device and a personal authentication method for identifying a user.

  In the field of information equipment and services, personal authentication systems using biometric information such as fingerprints, irises, veins, and faces have been used in many situations. The biometric authentication system reads a person's biometric feature in advance for a part of a person's physical feature, and registers the biometric feature as a pair with user information such as a user ID. Then, when a person uses the system or the like, it is compared using biometric information whether or not the user has a qualification registered in the system. If the degree of similarity is greater than or equal to a certain threshold, the user is authenticated and the system can be used. If the similarity is less than or equal to the threshold, the person is authenticated as an unauthorized person and the system is rejected.

Japan Automatic Recognition System Association, “Biometrics Identified with This”, page 137, 2001

  As described in Non-Patent Document 1, generally in a biometric authentication system, the error probability can be changed by a threshold value based on the similarity between biometric information. As shown in FIG. 1, there is a trade-off relationship between the probability of erroneously accepting another person (acceptance rate of other person: FAR) and the probability of erroneously rejecting the principal (personal rejection rate: FRR), and when one increases, the other decreases. There is a relationship. That is, the other person acceptance rate and the principal rejection rate cannot be set to 0 at the same time except for a biometric authentication system in which the error is not 0. In general, in order to increase the security level, it is necessary to set a threshold value at a value that lowers the acceptance rate of others. In that case, however, the rejection rate of the person increases and there is a problem that convenience is lowered.

  The present invention realizes a method that combines convenience while maintaining the security level by changing the threshold in biometric authentication according to the security level of password authentication in an authentication device that uses both authentication by password and biometric authentication. To do.

  In the present invention, authentication using a personal identification number is first performed, and a threshold value for biometric authentication is determined according to the security level of the personal identification number. Next, biometric authentication is performed. If the degree of similarity with the registered information is greater than the threshold value, the user is authenticated and the use of the device is permitted. If it is below the threshold, a password with a high security level is input again, and the threshold for biometric authentication is changed so that the person can be accepted easily. As described above, the user can control the threshold value for biometric authentication according to the security level of the password authentication, thereby realizing an apparatus having both convenience and security.

  The present invention is effective when biometric authentication fails in advance or when accuracy is expected to be low by manipulating the threshold value in biometric information according to the number of input digits of the password. In particular, if the authentication part in biometric authentication is a face and authentication is expected to fail, such as in a dark place, the authentication failure can be confirmed by executing biometric authentication after entering the upper digits of the password in advance. This has the effect of reducing the possibility.

  In addition, the present invention is effective in the case of a personal authentication system that possesses a plurality of IC cards and makes authentication successful only when all IC card authentication is successful. By using it together with biometric authentication, there is a possibility that authentication may be successful with a small number of IC cards, and the burden on the user can be reduced.

  Hereinafter, a personal authentication system using both biometric authentication and password authentication will be described. In this system, the identification number authentication and the biometric authentication are repeated a plurality of times, and when it is determined that the person is the same as the registered person, the authentication success is displayed, and otherwise the authentication failure is displayed.

  FIG. 1 is a functional block diagram showing a schematic configuration of an authentication system in the present embodiment. As shown in FIG. 1, the personal authentication system according to this embodiment includes a personal identification number acquisition device 10, a biometric information acquisition device 11, a personal feature storage unit 12, a personal identification number authentication determination unit 13, a biometric authentication determination unit 14, and an authentication count measurement. Means 15 and an authentication result display device 16 are provided.

  The personal identification number acquisition device 10 in the authentication system is used as a recovery use when the personal authentication by biometric authentication fails and as a threshold adjustment means. Since it can be carried out by using a publicly known one such as a keyboard, detailed illustration and explanation thereof will be omitted.

  The biometric information acquisition device 11 uses a camera in the case of face authentication and a microphone in the case of voice authentication. However, since a known device is used as the authentication device, detailed description thereof is omitted.

  The personal feature storage means 12 stores and accumulates the personal identification number and biometric information of an individual to be authenticated. As for biometric information, when data acquired by a biometric authentication acquisition device is held as it is, when it is converted into a feature amount and stored, or a feature amount is encrypted and stored, the biometric authentication acquisition device 11 Any holding method may be used as long as personal authentication is possible by collating with the obtained biometric features. Similarly, features obtained with other devices can be used if personal authentication is possible. Similarly, the personal identification number may be stored as it is or may be stored in an encrypted form, but any format may be used as long as authentication is possible.

  The personal identification number authentication determination unit 13 compares the personal identification number registered in the personal feature storage unit 12 with the personal identification number acquired from the personal identification number acquisition device, and compares and determines whether or not a correct number is input. A routine for determining whether or not the input for J digits is correct when the upper J digits (J <= L) are entered with all the L digits as the personal identification number is provided. In this means, the number of digits N of a correctly input personal identification number and a flag value F for determining whether an incorrect number has been input are output.

  The biometric authentication determination unit 14 compares the biometric information for registration stored in the personal feature storage unit 12 with the biometric information for verification acquired from the biometric information acquisition device, and determines the similarity as a threshold, thereby performing personal authentication. A function is provided for determining whether or not a person accessing the system is a registered person.

  The authentication result display means 15 has a function of measuring the number of times of authentication. Used to display authentication failure when the number of authentications exceeds the specified value.

  The authentication result display means 16 has a function of displaying whether or not the person who has accessed the authentication system is a registered person. This function can be implemented using a known device that can display the result, such as a display or an LED lamp.

  FIG. 2 is a flowchart of a processing procedure in this system. First, the number of authentications in the authentication number measuring means is initialized to 0 (step 101). Next, a personal identification number is acquired from the personal identification number acquisition device 10 such as a keyboard (step 102), and the personal identification number stored in the personal feature storage means is compared with the input number (step 103).

  Next, the entered password number is N digits, and the entire registered password number is L digits, and is compared with the upper N digits of the registered password number. If there is a mismatch, an authentication failure message is displayed (step 111). ) To finish. If all the passwords have been input (N = L), the authentication success is displayed and the process ends. Further, if the authenticated password is not all digits (N <L), the process proceeds to step 104, and the threshold value for biometric authentication is changed. For example, when N digits are input, the threshold for biometric authentication is changed from TH (FAR = C) to TH (FAR = C × 10 ^ N). Here, TH (FAR = C) means a threshold value at which the acceptance rate FAR of another person becomes a constant C, and TH (FAR = C × 10 ^ N) means a threshold value at which the FAR has a value C × 10 ^ N. To do. If the number of digits that is consistent with the registered password is N digits, it means that the number of attempts is accepted 10 ^ N times and accepted once, so that the acceptance rate FAR = 10 ^ Corresponds to (-N). The FAR of the biometric authentication after the change is C × 10 ^ N, and assuming that these are independent events, the total FAR of the biometric authentication and the password authentication is calculated as (10 ^ (− N)) × (C × 10 From ^ N), FAR = C, and the acceptance rate of others before inputting the password can be maintained. As described in the prior art, in a general biometric authentication system, when the FAR is increased, the identity rejection rate FRR is decreased. In other words, by changing the threshold value so that the FAR becomes higher according to the security level of the input of the personal identification number, the possibility of rejecting the person is reduced, and the authentication success rate is increased.

  In S105, the biometric information acquired by the biometric information acquisition device 11 is compared with the information registered in the personal feature storage means 12, and the similarity is calculated. The similarity calculation method uses, for example, normalized correlation between feature quantities. As a result of the comparison between the biometric features, when the similarity is equal to or greater than the threshold, the authentication success is displayed on the authentication result display device 16 and the process is terminated. If the number of authentications is less than the threshold, the number of authentications is updated (step 108). If the number of authentications is equal to or greater than the predetermined number, an authentication failure is displayed and the process ends (step 110). If the number of authentications is within the predetermined number, the process returns to step S102 and the acquisition of the personal identification number is performed again. When the password is entered for the second time or later, the process starts from the next digit of the password entered before that time (step 103). In step 104, as in the first time, the threshold value for biometric authentication is changed according to the number of digits to which the password is input. The same operation is repeated until the number of authentications exceeds the specified value. When the number of authentications exceeds the specified number, an authentication failure is displayed and the process ends (step 110).

  The personal authentication system using both biometric authentication and IC card authentication in the second embodiment will be described below. This system is premised on having a plurality of IC authentication cards. The personal authentication system in the second embodiment includes an IC card information acquisition device 20, a biometric information acquisition device 21, a personal feature storage means 22, an IC card authentication determination means 23, a biometric authentication determination means 24, an authentication count measurement means 25, An authentication result display device 26 is provided. Except for the IC card information acquisition device 20 and the IC card authentication determination means 23, the second embodiment is the same as the first embodiment, and only the differences will be described.

  The IC card information acquisition device 20 is used as a recovery use and threshold adjustment unit when personal authentication by biometric authentication fails. Since a known device such as an IC card reader can be used, detailed illustration and explanation thereof will be omitted.

  The IC card authentication determination means 23 compares the password number in the IC card registered in the personal feature storage means 22 with the password number obtained from the IC card information acquisition device, and compares whether the correct number is input or not. ·judge. This means outputs the number N of correctly authenticated IC cards and a flag value F for determining whether or not an incorrect number has been input. Instead of the number of digits of the personal identification number in the first embodiment, the number N of correctly authenticated IC cards is a parameter for adjusting the threshold for biometric authentication.

It is a figure which shows the relationship between a FRR curve and a FAR curve. It is a functional block diagram which shows embodiment of the personal authentication system in the 1st Embodiment of this invention. It is a flowchart which shows the authentication processing procedure in the 1st Embodiment of this invention. It is a functional block diagram which shows embodiment of the personal authentication system in the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 PIN number acquisition device 11 Biometric information acquisition device 12 Personal characteristic memory | storage means 13 PIN number authentication determination means 14 Biometric authentication determination means 15 Authentication frequency measurement means 16 Authentication result display device 20 IC card information acquisition device 21 Biometric information acquisition device 22 Personal characteristics Storage means 23 IC card authentication determination means 24 Biometric authentication determination means 25 Authentication frequency measurement means 26 Authentication result display device

Claims (12)

A personal authentication device using both biometric authentication and another authentication method, wherein the biometric authentication threshold is changed according to the security level of the other authentication method. 2. The personal authentication device according to claim 1, wherein a threshold value of the biometric authentication is set so as to facilitate acceptance of the person when a high security level is achieved by the other authentication method. apparatus. The personal authentication apparatus according to claim 1, wherein the other authentication method is an authentication method using a password, and the security level is a length of a password. 2. The personal authentication apparatus according to claim 1, wherein the other authentication method is an authentication method using an IC card, and the security level is the number of IC cards that have been successfully authenticated. An individual who performs authentication by using a new authentication device when authentication fails in biometric authentication, changes the threshold value of the biometric authentication according to the security level in the new authentication method, and performs authentication again Authentication device. 6. The personal authentication apparatus according to claim 5, wherein the new authentication method is a password authentication method, and the security level is a password length. A personal authentication method using both biometric authentication and another authentication method, wherein the threshold value of the biometric authentication is changed according to the security level of the other authentication method. 8. The personal authentication method according to claim 7, wherein when the high security level is achieved by the other authentication method, the biometric authentication threshold is set so as to facilitate acceptance of the person. Method. 8. The personal authentication method according to claim 7, wherein the other authentication method is a password authentication method, and the security level is a password length. 8. The personal authentication method according to claim 7, wherein the other authentication method is an authentication method using an IC card, and the security level is the number of IC cards successfully authenticated. A personal authentication method characterized by performing authentication by a new authentication method when authentication fails in biometric authentication, changing the threshold value of the biometric authentication according to the security level in the new authentication method, and performing authentication again . 12. The personal authentication method according to claim 11, wherein the new authentication method is a password authentication method, and the security level is a password length.

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