JP7140409B2 - Authentication device, authentication method and program - Google Patents

Description

The present invention relates to an authentication device, method and program.

There was a security problem such as the risk of impersonation if the content of the password was asked during password authentication. As a technique for solving this problem, Patent Literature 1 discloses an authentication system that sets a password for each keyword category in advance. Here, a keyword category is a classification (category) having a plurality of words as elements.

Specifically, the authentication system according to Patent Literature 1 randomly outputs a plurality of words by voice. Then, the authentication system authenticates the user by speaking the password for each keyword category to which each word belongs. For example, the authentication system audibly outputs ""monkey", "apple", and "car". In this case, the user associates "animal" as a keyword category to which "monkey" belongs, "fruit" as a keyword category to which "apple" belongs, and "vehicle" as a keyword category to which "car" belongs. Then, if the authentication system has set the passwords for each keyword category as "love" for "animals", "up" for "fruits", and "oka" for "vehicles", when the user utters "aiueoka" If you succeed in authentication and make other utterances, authentication will fail.

JP 2010-102383 A

However, in the method of the authentication system according to Patent Document 1, it is necessary to remember a plurality of passwords corresponding to keyword categories. In addition, there are concerns such as forgetting the order of keyword categories. In other words, there is a problem that a burden is placed on the user when authenticating the user.

An object of the present disclosure is to provide an authentication device, method, and program capable of reducing the burden on the user and improving security by solving such problems.

The authentication device of the present disclosure includes a voice information control unit that acquires a password input by voice by a user, extracts categories corresponding to words included in the password, and extracts the number of words for the extracted category, an authentication control unit that determines whether or not to authenticate the user based on whether the number of words for the category set by the user matches, It is determined that the authentication of the user is successful, and if not, it is determined that the authentication of the user is unsuccessful.

The method of the present disclosure obtains a password voice-inputted by a user, extracts categories corresponding to words included in the password, and sets the number of words for the extracted categories and the number of words set in advance by the user. and determining whether the user is authenticated based on whether the number of words for the identified category matches, wherein determining the user's authentication includes, if the match, the user determining that the authentication of the user is successful, and if the mismatch, determining that the authentication of the user has failed.

The program of the present disclosure includes a process of acquiring a password input by voice by a user, extracting categories corresponding to words included in the password, and setting the number of words for the extracted category and the number of words set in advance by the user. and a process of determining whether or not the user is authenticated based on whether or not the number of words for the identified category matches, and the process of determining authentication of the user is performed when the , determining that the authentication of the user has succeeded, and determining that the authentication of the user has failed if there is no match.

INDUSTRIAL APPLICABILITY According to the present disclosure, it is possible to provide an authentication device, method, and program capable of reducing the burden on a user and improving security when authenticating the user.

1 is a block diagram showing the configuration of an authentication device according to a first embodiment; FIG. 4 is a flow chart showing the operation of the authentication device according to the first embodiment; FIG. 11 is a block diagram showing the configuration of an authentication system according to a second embodiment; FIG. It is a figure which shows an example of the authentication rule table which concerns on 2nd Embodiment. It is a figure which shows an example of the category table which concerns on 2nd Embodiment. 10 is a flow chart showing operation of advance preparation of the authentication device according to the second embodiment. 9 is a flow chart showing the operation of user authentication of the authentication device according to the second embodiment; FIG. 9 is a sequence diagram showing operations of an authentication system according to the second embodiment; It is a block diagram which shows the structure of the computer which concerns on this embodiment.

Hereinafter, specific embodiments to which the present disclosure is applied will be described in detail with reference to the drawings. In each drawing, the same elements are denoted by the same reference numerals, and redundant description will be omitted as necessary for clarity of description.

(First embodiment)
First, using FIG. 1, the configuration of the authentication device 10 according to the first embodiment will be described. The authentication device 10 has a function of executing user authentication according to a rule predetermined by the user, and includes a voice information control section 11 and an authentication control section 12 .

The voice information control unit 11 acquires a password voice-inputted by the user. The authentication control unit 12 extracts categories corresponding to the words included in the password. Then, the authentication control unit 12 determines user authentication based on whether or not the number of words for the extracted category matches the number of words for the category set in advance by the user.

Next, operation of the authentication device 10 according to the first embodiment will be described with reference to FIG.
First, the voice information control unit 11 acquires a password voice-inputted by the user (step S11). Next, the authentication control unit 12 extracts categories corresponding to the words included in the password (step S12). Next, the authentication control unit 12 determines whether or not to authenticate the user based on whether or not the number of words for the extracted category matches the number of words for the category preset by the user ( step S13). In step S13, when the number of words for the extracted category matches the number of words for the category preset by the user, the authentication control unit 12 determines that the user has been successfully authenticated. on the other hand. If the number of words for the extracted category does not match the number of words for the category preset by the user, the authentication control unit 12 determines that user authentication has failed.

In the authentication device 10 according to the first embodiment, the user only has to memorize the preset category and the number of words for the category for authentication. Therefore, there is no need to remember multiple passwords corresponding to keyword categories. Also, since the order of the words included in the password does not matter, the order of the keyword categories corresponding to the words does not matter. Therefore, the authentication device 10 can reduce the burden on the user when authenticating the user.

(Second embodiment)
Next, the configuration of the authentication system 2 according to the second embodiment will be described using FIG. As shown in FIG. 3 , the authentication system 2 includes an authentication device 10 , an authenticated device 20 and an input/output device 30 . The authentication device 10 connects to the device to be authenticated 20 via a network to perform wireless or wired communication. The device to be authenticated 20 is connected to the input/output device 30 to perform wireless communication or wired communication.

<Authentication device 10>
The authentication device 10 is, for example, a server that has a function of performing user authentication according to rules predetermined by the user. The authentication device 10 includes a voice information control section 11 and an authentication control section 12 .

<Voice Information Control Unit 11>
The voice information control unit 11 connects to the authentication control unit 12 and the device to be authenticated 20 . The voice information control section 11 includes a voice information processing section 111 , a control section 114 and a storage section 117 . The voice information processing unit 111 performs conversion processing of voice information. The control unit 114 executes data control. Storage unit 117 stores data.

The speech information processing unit 111 includes a text-to-speech conversion unit 112 and a speech-to-text conversion unit 113 . The text-to-speech conversion unit 112 converts the text acquired from the response information storage unit 119 into voice response information for the user. The voice-text conversion unit 113 converts the user's voice input information (eg, password) input to the input/output device 30 acquired from the voice storage unit 118 into text, and stores the converted text in the text storage unit 1110. do.

The control unit 114 includes a silence detection unit 115 and a transmission/reception control unit 116 . Silence detector 115 detects the end time of the user's voice input. The transmission/reception control unit 116 executes data transmission/reception between the device to be authenticated 20 and the authentication control unit 12 . For example, the transmission/reception control unit 116 transmits the voice response information converted by the text-speech conversion unit 112 to the device 20 to be authenticated, and causes the input/output device 30 to output the voice response information. Further, the transmission/reception control unit 116 transmits the character string converted to text by the voice-text conversion unit 113 to the authentication control unit 12 .

The storage unit 117 includes a voice storage unit 118 , a response information storage unit 119 and a text storage unit 1110 . The voice storage unit 118 stores user's voice input information input to the input/output device 30 . The response information storage unit 119 stores response information to the user in text form. The response information stored in text format is converted into voice data by the text-speech converter 112 and used for voice output to the user. Also, the response information storage unit 119 may store voice data generated in advance without going through the text-speech conversion unit 112 . The text storage unit 1110 stores the character strings converted into text by the speech-text conversion unit 113 .

<Authentication control unit 12>
Authentication control unit 12 connects to voice information control unit 11 . The authentication control unit 12 has a control unit 121 and a storage unit 123 . The control unit 121 executes data control. The storage unit 123 stores data.
The control unit 121 includes a transmission/reception control unit 122 and an authentication approval/disapproval determination unit 127 .
The transmission/reception control unit 122 executes data transmission/reception.

The authentication propriety determination unit 127 executes user authentication based on whether the password input by the user complies with the authentication rule set by the user. Authentication propriety determination unit 127 uses the category table stored in category storage unit 126 to extract categories corresponding to words included in the password input by the user obtained from voice information control unit 11 . The authentication propriety determination unit 127 determines whether or not the number of words for the extracted category matches the number of words for the category set in the authentication rule table stored in the authentication rule storage unit 124. to determine whether or not to authenticate. In addition, the authentication propriety determination unit 127 stores the word included in the password, the word included in the password used when the user set in the authentication rule table stored in the authentication rule storage unit 124 performed the previous authentication, match, it is determined that user authentication has failed.

In addition, the authentication rule table of the authentication rule storage unit 124 can store words included in past passwords used when the user performed authentication in the past, not limited to the previous authentication. In that case, a plurality of types of past passwords may be stored as a history, for example, in order of user authentication time. Hereinafter, the number of past passwords that can be stored in the authentication rule storage unit 124 will be referred to as the invalid history count. Here, if the word included in the password and the word included in the past password match in any of the past passwords, the authentication propriety determination unit 127 determines that user authentication has failed.
Also, in the authentication rule table of the authentication rule storage unit 124, an invalid period can be set for past passwords. When the invalid period expires, the past password with the invalid period set is deleted.

The storage unit 123 includes an authentication rule storage unit 124 , a text storage unit 125 and a category storage unit 126 . The authentication rule storage unit 124 stores, for each user, a user authentication rule table that stores information on authentication rules corresponding to users. The authentication rule table stores, for example, information as shown in FIG. 4 (described later). Text storage unit 125 stores the character string received from voice information control unit 11 . The text storage unit 125 stores, for example, user IDs and identification information used to authenticate users. The category storage unit 126 stores a category table representing data on inclusion relationships of word categories. The category storage unit 126 stores, for example, information as shown in FIG. 5 (described later). The words stored in the category table may be added or deleted by the user.

<Authenticated Device 20>
The device to be authenticated 20 is, for example, an entrance door, a work support system on a network, a shopping site, or the like.
<Input/output device 30>
The input/output device 30 has a function as a microphone/speaker, and is, for example, a hearable device, a smart speaker, a smart phone, or a telephone terminal. Note that the device to be authenticated 20 may have the function of the input/output device 30 .

Next, the preparation operation of the authentication device 10 according to the second embodiment will be described with reference to FIG. The preparatory operation is an operation of registering a user ID and an authentication rule required for password collation in the authentication rule table of the authentication rule storage unit 124 . Here, a user ID is a character string that can uniquely identify a user.

First, the authentication device 10 registers the user ID for the user in the authentication rule table stored in the authentication rule storage unit 124 according to an instruction from the user (step S101). The authentication device 10 sets, for example, a user ID of "Taro Nichiden" for the user, and as shown in FIG. ” is registered.

Next, the authentication device 10 registers the category and the number of words for the category in the authentication rule table according to the instruction from the user (step S102). The categories and the number of words for the categories represent the user's authorization rules. A category is a classification having multiple words as elements. For example, the category "sports" has words such as "baseball" and "tennis" as elements. The number of words is the number of words entered by the user at the time of authentication. For example, the authentication device 10 acquires the category “sports” and the number of words “2” from the user input, and puts “sports” and “category #1” in the “category #1” item of the authentication rule table shown in FIG. Register “2” in the “Number of 1s” item.

Next, the authentication device 10 determines whether or not to add an authentication rule according to the user's instruction (step S103). When adding an authentication rule (step S103 YES), the authentication device 10 executes the process of step S102. On the other hand, if no authentication rule is to be added (step S103 NO), the authentication device 10 terminates the process.
By processing YES in step S103, the number of categories and words, which are components of the authentication rule, can be added as necessary. By adding more categories and more words, you can increase the strength of your password.

After the presetting in steps S101 to S103, the authentication rule table shown in FIG. 4 indicates the authentication rule for the user corresponding to the user ID "Taro Nichiden". The authentication rule requires the user to provide a password consisting of two words from the "sports" category, one word from the "vegetables" category, and one word from the "aquatic animals" category.

Next, the user authentication operation of the authentication device 10 according to the second embodiment will be described with reference to FIG. The authentication device 10 receives a user ID and a password as input elements when authenticating a user.

First, the transmission/reception control unit 122 of the authentication control unit 12 of the authentication device 10 acquires a user ID from the user via the input/output device 30 (step S201). The transmission/reception control unit 122 acquires, for example, a user ID input by the user to the input/output device 30 using an IC card key. The method of inputting the user ID is not limited to this embodiment, and when used for user authentication in a telephone system, the authentication device 10 may acquire the user ID by notifying the caller's number.

Next, the text-to-speech conversion unit 112 of the speech information control unit 11 converts the response information "Please speak your password" for requesting the password from the user stored in the text format in the response information storage unit 119 into voice. Convert. Then, the transmission/reception control unit 116 causes the input/output device 30 to output the converted voice "Please speak your password" (step S202). Note that the output voice is not limited to "Please speak your password" as long as it is a voice for requesting a password.

Next, the transmission/reception control unit 116 acquires the password voice-inputted by the user from the input/output device 30 (step S203). The voice-text converter 113 converts the acquired password from voice to text. The transmission/reception control unit 116 transmits the text-converted password to the authentication control unit 12 .

Next, the transmission/reception control unit 122 of the authentication control unit 12 receives the text-converted password from the voice information control unit 11 . The password entered in this authentication is hereinafter referred to as the password entered in this authentication (current password). Then, the authentication propriety determination unit 127 extracts words from the current password.

Thereafter, the authentication propriety determination unit 127 authenticates the current password.
First, the authentication availability determination unit 127 acquires an authentication rule table corresponding to the user ID from the authentication rule storage unit 124 . Next, the authentication propriety determination unit 127 determines whether or not the word included in the current password matches the word included in the same user's password at the time of previous authentication (previous password) (step S204). . Here, the word included in the previous password is a word included in the “previous authentication word” item of the authentication rule table of the authentication rule storage unit 124 .

If all the words included in the current password match all the words included in the previous password (step S204 YES), the authentication permission determination unit 127 does not permit authentication of the current password. For example, the authentication permission determination unit 127 determines that the current password includes “baseball,” “tennis,” “cabbage,” and “whale,” and the “previous authentication word” in the authentication rule table shown in FIG. If "'baseball', 'tennis', 'cabbage', 'whale'" is included, user authentication is not permitted.

If the user authentication is not permitted, the transmission/reception control unit 116 causes the input/output device 30 to output a voice message indicating that the user authentication has failed, "authentication failed" (step S207). Specifically, the transmission/reception control unit 122 notifies the voice information control unit 11 that user authentication has failed. Even if the order of the words is changed, authentication will fail in the same way. Then, the text-to-speech conversion unit 112 of the voice information control unit 11 notifies the user stored in the text format in the response information storage unit 119 that the user authentication has failed, in accordance with the notification of the user authentication failure. Converts the response information "Authentication failed." to voice. Then, the transmission/reception control unit 116 causes the input/output device 30 to output the converted voice "Authentication failed." Note that the output voice is not limited to "Authentication failed" as long as it is a voice for notifying that user authentication has failed. The authentication device 10 then ends the process. Therefore, it is possible to prevent impersonation by a third party who heard the user's utterance by not being able to authenticate with the same words as the previous authentication.

On the other hand, if all the words included in the current password and all the words included in the previous password do not match (step S204 NO), the authentication permission determination unit 127 determines whether or not the authentication rules are followed ( step S205).

Specifically, first, the authentication propriety determination unit 127 determines to which category each word included in the current password belongs by referring to the category table of the category storage unit 126 shown in FIG. As shown in FIG. 5, the category table includes categories for sports K1, food K2, and animals K3. The sports K1 category includes ball games K11, track and field K12, and martial arts K13 categories. The category of food K2 includes categories of vegetables K21, fruits K22, and dishes K23. The animal K3 category includes land animal K31 and aquatic animal K32 categories. In other words, categories are hierarchized, and lower categories exist within higher categories. And, for example, the ball game K11 category includes the words tennis, baseball, and basketball. The Aquatic Animals K32 category also includes the words whale, jellyfish, shark, dolphin, and seal.

Here, it is assumed that the passwords this time are "'basketball', 'judo', 'paprika', and 'whale'". In this case, the authentication propriety determination unit 127 refers to the category table shown in FIG. 5, extracts the category of sports K1 from "basketball" and "judo", and extracts the category of vegetables K21 from "publica". , the category of aquatic animals K32 is extracted from "whale". That is, the authentication propriety determination unit 127 determines that the current password is composed of two words from the sports K1 category, one word from the vegetables K21 category, and one word from the aquatic animals K32 category. do.

Next, the authentication propriety determination unit 127 refers to the authentication rule table shown in FIG. 4, acquires the category and the number of words for the category, and authenticates the current password based on the acquired information. For example, "category #1" and "number of category #1" in the authentication rule table shown in FIG. "Vegetables" and "1" are included, and "Category #3" and "Number of Category #3" include "Aquatic Animals" and "1", respectively. Based on the information in the authentication rule table, the authentication approval/disapproval determination unit 127 determines that the current password consists of two words from the sports category, one word from the vegetables category, and one word from the aquatic animals category. , it is determined that the current password complies with the authentication rules. On the other hand, if the current password does not consist of two sports category words, one vegetable category word, and one aquatic animal category word, the current password is determined not to comply with the authentication rules. Therefore, the authentication device 10 can determine whether the password entered by the user conforms to the authentication rule preset by the user.

Next, if the authentication rule is complied with (step S205 YES), the authentication propriety determination unit 127 permits the authentication of the current password (step S206). The authentication device 10 then ends the process. On the other hand, if the authentication rule is not followed (step S205 NO), the authentication device 10 proceeds to the process of step S207. The authentication device 10 then ends the process.

In step S204, it is determined whether or not the word included in the current password matches the word included in the same user's previous password. May be set.
The same password invalid period is a period during which password authentication based on the same combination of words is invalid. For example, when setting an invalid period, after the user has successfully authenticated, the word included in the current password is registered in the "previous authentication word" of the authentication rule table shown in FIG. "Invalid period" is associated with and registered. After that, the invalid period is reduced each time one day elapses, and when it reaches 0 days, the corresponding "previous authentication word" is deleted. A plurality of "previous authentication words" and "invalid periods" may be registered in the authentication rule table.

The number of times of invalid history is the number of times of history in which authentication of the same password as in the past history is invalidated. If the number of times of invalidation history is set to 10, the same history as the last 10 times is invalidated at the time of password authentication. FIG. 4 shows an example in which the invalid history count is one. When the number of times of invalidation history is five, for example, five "previous authentication words" are registered in the authentication rule table of FIG. 4 in the order of user authentication time. Then, when the user is successfully authenticated, the oldest "previous authentication word" is deleted, and the words included in the current password are added to the "previous authentication word".

Also, the importance may be reflected in the invalid period or invalid history count. Importance is the strength of security in a system where user authentication is used. The higher the importance, the higher the security strength. For example, in the case of a system that handles personal information and trade secrets and is greatly affected by password leaks, the importance level is preferably set to "high". For example, if the importance is low, the invalid period is 1 day, if the importance is medium, the invalid period is 5 days, and if the importance is high, the invalid period is 10 days. Similarly, when the importance is low, the number of invalid histories is 1, when the importance is medium, the number of invalid histories is 5, and when the importance is high, the number of invalid histories is 10.

Next, the operation of the authentication system 2 will be explained using FIG. As an example, a case where the device to be authenticated 20 is an entrance door (especially at night/holidays when there is no guard) will be described. It is assumed that the device to be authenticated 20 has an input/output device 30 .

First, after the user holds the IC card key over the device to be authenticated 20, the device to be authenticated 20 issues an authentication request to the authentication device 10 (step S301). Next, the authentication device 10 requests a user ID from the device to be authenticated 20 (step S302).
The device to be authenticated 20 acquires the employee number and the like from the IC card key, and acquires the user ID corresponding to the employee number. Then, the device to be authenticated 20 transmits the acquired user ID as text data to the authentication device 10 (step S303). Next, after receiving the user ID, the authentication device 10 requests a password from the device to be authenticated 20 (step S304). Next, the device to be authenticated 20 causes the input/output device 30 to output a voice requesting the password from the user (step S305). For example, the device to be authenticated 20 causes the input/output device 30 to output "Please speak your password." Here, the device to be authenticated 20 outputs a voice requesting the password to the user, and then starts recording the voice (step S306). Here, the device to be authenticated 20 detects silence (step S307). Next, the user inputs a password to the input/output device 30 by voice, and the input/output device 30 transmits the input password to the device to be authenticated 20 (step S308). After receiving the password from the input/output device 30, the device to be authenticated 20 ends the recording (step S309). Next, the device to be authenticated 20 transmits voice data of the acquired password to the authentication device 10 (step S310).

Next, the voice information control unit 11 of the authentication device 10 converts the acquired password from voice to text (step S311), and transmits the converted password and user ID to the authentication control unit 12 (step S312). ). Next, the authentication control unit 12 uses the password and the user ID to determine whether user authentication is possible (step S313). Specifically, the authentication control unit 12 executes the processes of steps S204 to S206 described above to determine whether or not user authentication is possible. Next, the authentication control unit 12 notifies the voice information control unit 11 of the authentication result (step S314). Next, the voice information control unit 11 transmits the received authentication result to the device to be authenticated 20 (step S315). Finally, when the authentication result is authentication success, the device to be authenticated 20 notifies the user of the authentication success with, for example, a blue lamp or a beep sound, and opens the entrance door (step S316).

In this embodiment, the device to be authenticated 20 outputs voice and records voice data, but the authenticating device 10 may do so.

The authentication device 10 according to the second embodiment has the same effects as the authentication device 10 according to the first embodiment.
In addition, since the authentication device 10 executes user authentication by inputting a password by voice, two-step authentication using an IC card key and a password can be performed without an input means such as an operation panel, thereby enhancing security.

Moreover, in the authentication device 10, since the password is based on the rule specified by the user (authentication rule), the risk of the user forgetting the password can be kept low.
Further, in the authentication device 10, categories are included in categories in the category table. By using an inclusive relationship, rules can be set in detailed categories for detailed content, and rules can be set in general categories for less detailed content, making it easier to remember passwords (especially if a word is different from the previous one). can remember).

It should be noted that the present invention is not limited to the above embodiments, and can be modified as appropriate without departing from the scope of the invention.

<Hardware configuration>
Next, a hardware configuration example of the computer 1000 relating to the authenticating device 10, the device to be authenticated 20, and the input/output device 30 will be described with reference to FIG. A computer 1000 in FIG. 9 has a processor 1001 and a memory 1002 . The processor 1001 may be, for example, a microprocessor, an MPU (Micro Processing Unit), or a CPU (Central Processing Unit). Processor 1001 may include multiple processors. Memory 1002 is comprised of a combination of volatile and non-volatile memory. Memory 1002 may include storage remotely located from processor 1001 . In this case, processor 1001 may access memory 1002 via an I/O interface (not shown).

Further, each device in the above-described embodiments is configured by hardware or software, or both, and may be configured by one piece of hardware or software, or may be configured by multiple pieces of hardware or software. The functions (processing) of each device in the above-described embodiments may be implemented by a computer. For example, a program for performing the method in the embodiment may be stored in the memory 1002 and each function may be realized by executing the program stored in the memory 1002 with the processor 1001 .

These programs can be stored and delivered to computers using various types of non-transitory computer readable media. Non-transitory computer-readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (eg, flexible discs, magnetic tapes, hard disk drives), magneto-optical recording media (eg, magneto-optical discs), CD-ROMs (Read Only Memory), CD-Rs, CD-R/W, semiconductor memory (eg, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (random access memory)). The program may also be delivered to the computer on various types of transitory computer readable medium. Examples of transitory computer-readable media include electrical signals, optical signals, and electromagnetic waves. Transitory computer-readable media can deliver the program to the computer via wired channels, such as wires and optical fibers, or wireless channels.

2 authentication system 10 authentication device 11 voice information control unit 12 authentication control unit 20 device to be authenticated 30 input/output device 111 voice information processing unit 112 text-speech conversion unit 113 voice-text conversion unit 114 control unit 115 silence detection unit 116 transmission/reception control Unit 117 Storage unit 118 Voice storage unit 119 Response information storage unit 121 Control unit 122 Transmission/reception control unit 123 Storage unit 124 Authentication rule storage unit 125 Text storage unit 126 Category storage unit 127 Authentication propriety determination unit 1000 Computer 1001 Processor 1002 Memory 1110 Text storage Department

Claims (10)

a voice information control unit for acquiring a password voice-inputted by a user;
categories corresponding to the words contained in the password are extracted, and based on whether or not the number of words for the extracted category matches the number of words for the category set in advance by the user; an authentication control unit that determines whether or not to authenticate a user;
The authentication control unit determines that the authentication of the user has succeeded if the match occurs, and determines that the authentication of the user has failed if the match does not match. The authentication control unit is
pre-stores the previous password used when the user performed the previous authentication,
2. If the word included in the current password used by the user for the current authentication matches the word included in the previous password, it is determined that the authentication of the user has failed. Authenticator as described. The authentication control unit is
storing in advance a past password used when the user authenticated in the past,
determining that the authentication of the user has failed if the word included in the current password used by the user for the current authentication matches the word included in the past password;
A predetermined number of the past passwords are stored;
The authentication device according to claim 1. The authentication control unit is
setting an invalid period for the past password stored in advance;
The authentication device according to claim 3, wherein when the invalid period expires, the past password set with the invalid period is deleted. The authentication device according to any one of Claims 1 to 4, wherein the categories are hierarchical, and a lower category exists in a higher category. The authentication device according to any one of claims 1 to 5, wherein the authentication control unit notifies the user when it is determined that the authentication of the user has failed. An authentication method executed by a computer of an authentication device,
obtaining a password spoken by a user;
categories corresponding to the words contained in the password are extracted, and based on whether or not the number of words for the extracted category matches the number of words for the category set in advance by the user; determining whether the user is authenticated,
In determining authentication of the user, the computer determines that the authentication of the user has succeeded if the match occurs, and determines that the authentication of the user has failed if the match does not occur.
Authentication method. Determining whether the user is authenticated includes:
pre-stores the previous password used when the user performed the previous authentication,
Determining that the authentication of the user has failed if the word included in the current password used by the user for the current authentication matches the word included in the previous password The authentication method according to Item 7. computer of the authentication device,
means for obtaining a password spoken by a user;
categories corresponding to the words contained in the password are extracted, and based on whether or not the number of words for the extracted category matches the number of words for the category set in advance by the user; It functions as a means of determining whether or not user authentication is possible,
A means for judging authentication of the user judges that the authentication of the user has succeeded if the match occurs, and that the authentication of the user has failed if the match does not occur. The means for determining whether the user is authenticated is
pre-stores the previous password used when the user performed the previous authentication,
10. If the word included in the current password used when the user performed the current authentication matches the word included in the previous password, it is determined that the authentication of the user has failed. program as described.

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