JP2002245244A - Authentication method, authentication device, storage medium, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an authentication method having a higher security effect. SOLUTION: A user, who is presented with a random alphanumeric string issued by an authentication device, converts the presented alphanumeric string, based on a 'conversion method' registered in the authentication device in advance and transmits a converted alphanumeric string to the authentication device. The authentication device authenticates the legality of the user, by converting the alphanumeric string presented to the user, based on the 'conversion method' registered by the user and by comparing the converted alphanumeric string with the alphanumeric string converted by the user and transmitted from the user.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an authentication method, an authentication device, a recording medium, and a program, and more particularly to a technique for authenticating a user.

[0002]

2. Description of the Related Art Generally, a password input when a cash card is used is a password which is arbitrarily determined in advance by a user.
It is a number that has been registered in the authentication system as a digit number.

[0003]

By the way, when using a cash card, even if it is the account holder, the cash card cannot be used unless a registered password is entered. Therefore, the user often uses a familiar number such as a date of birth or a telephone number as the personal identification number so as not to forget the personal identification number. In such a case, for example, if the wallet containing the cash card or license is dropped, the cash card is easily misused based on the date of birth etc. written on the license Problem.

The present invention has been made in view of the above circumstances, and has as its object to provide an authentication method, an authentication device, a recording medium, and a program having higher security effects.

[0005]

In order to solve the above-mentioned problems, an authentication method according to the present invention issues an arbitrary alphanumeric string and presents the issued alphanumeric string to a user. Receiving the input alphanumeric string; converting the issued alphanumeric string based on a conversion scheme registered in advance by a user; and receiving the received alphanumeric string and the converted alphanumeric string. A step of comparing with a numeric string to determine whether they match, and, in the determination, when it is determined that the two alphanumeric strings match, a user who has input the received alphanumeric string is valid. Determining that the user is a user. According to this configuration, the alphanumeric string arbitrarily issued is converted based on a conversion method registered in advance by the user, and the converted alphanumeric string is compared with the alphanumeric string received from the user. If the two alphanumeric strings match in this comparison, the alphanumeric string received from the user is determined to be an alphanumeric string that has been properly converted based on a conversion method registered in advance by the user, This user can be determined to be a valid user.

Further, the authentication method according to the present invention includes the steps of: issuing an arbitrary alphanumeric string and presenting the issued alphanumeric string to a user; receiving an alphanumeric string input by the user; Inversely converting the received alphanumeric string based on a conversion method registered in advance by a user; comparing the issued alphanumeric string with the inversely converted alphanumeric string to determine whether they match. Determining whether the received alphanumeric string is a valid user if the two alphanumeric strings are determined to match in the determination. It is characterized by:

Further, the authentication device according to the present invention issues an arbitrary alphanumeric string and presents the issued alphanumeric string to the user, and a receiving section which receives the alphanumeric string input by the user. And a conversion unit that converts the issued alphanumeric string based on a conversion method registered in advance by a user, and compares the received alphanumeric string with the converted alphanumeric string so that they match. Determining whether or not the two alphanumeric strings match, and determining that the user who has input the received alphanumeric string is a valid user. .

Further, the authentication device according to the present invention issues an arbitrary alphanumeric string and presents the issued alphanumeric string to the user, and a receiving section which receives the alphanumeric string input by the user. And, a reverse conversion unit that reversely converts the received alphanumeric string based on a conversion method registered in advance by the user, and compares the issued alphanumeric string with the inversely converted alphanumeric string. Determining whether the two alphanumeric strings match, and determining that the user who has input the received alphanumeric string is a legitimate user. Features.

Further, the recording medium according to the present invention provides a computer for issuing an arbitrary alphanumeric string, presenting the issued alphanumeric string to a user, and receiving the alphanumeric string input by the user. Receiving means, a converting means for converting the issued alphanumeric string based on a conversion method registered in advance by the user, and the received alphanumeric string,
Determine whether or not they match by comparing the converted alphanumeric strings, when it is determined that the two alphanumeric strings match,
A program for recording a program for functioning as a judging means for judging that a user who has input the received alphanumeric string is a valid user is recorded.

[0010] Further, the recording medium according to the present invention provides a computer for issuing an arbitrary alphanumeric string, presenting the issued alphanumeric string to a user, and receiving an alphanumeric string input by the user. Receiving means, and reverse conversion means for reversely converting the received alphanumeric string based on a conversion method registered in advance by the user, the issued alphanumeric string, and the inversely converted alphanumeric string. Is compared with each other to determine whether they match, and when it is determined that the two alphanumeric strings match, a function as a determination means for determining that the user who has input the received alphanumeric string is a valid user The program is characterized by recording a program for causing the program to be executed.

[0011] The program according to the present invention also causes a computer to issue an arbitrary alphanumeric string and present the issued alphanumeric string to a user, and to receive an alphanumeric string input by the user. Receiving means, a converting means for converting the issued alphanumeric string based on a conversion method registered in advance by a user, and comparing the received alphanumeric string with the converted alphanumeric string It is determined whether or not they match, and when it is determined that the two alphanumeric strings match, it is made to function as determination means for determining that the user who has input the received alphanumeric string is a valid user. And

[0012] A program according to the present invention causes a computer to issue an arbitrary alphanumeric string and present the issued alphanumeric string to a user, and to receive an alphanumeric string input by the user. Receiving means, reverse conversion means for reversely converting the received alphanumeric string based on a conversion method registered in advance by a user, the issued alphanumeric string, and the inversely converted alphanumeric string, By comparing and determining whether or not the two strings match, when it is determined that the two strings match, the user who has input the received alphanumeric string functions as a determination unit that determines that the user is a valid user. It is characterized by:

[0013]

Next, embodiments of the present invention will be described with reference to the drawings. Such an embodiment shows one aspect of the present invention, and does not limit the present invention. Further, the present invention can be arbitrarily changed within the scope of the technical idea.

[1] Principle of Authentication Using “Conversion Method” First, in the present embodiment, user authentication is performed using information for converting an alphanumeric string called “conversion method”. The principle of authentication using the “conversion method” performed in the present embodiment will be described. In the present embodiment, the user presented with the random alphanumeric string A issued from the authenticating side that authenticates the user's legitimacy has registered the presented alphanumeric string A in advance on the authenticating side. The conversion is performed based on the "conversion method", and the converted alphanumeric string B is transmitted to the authentication side, thereby authenticating the validity of the user. Then, on the authentication side, the alphanumeric string A presented to the user is converted based on the “conversion method” registered by the user, and the converted alphanumeric string B ′ is converted by the user received from the user. The authenticity of the user is authenticated by comparing it with the alphanumeric string B after completion.

Here, the above-mentioned "conversion method" will be described. First, the "conversion method" includes information on how to convert an alphanumeric string and which digit of the alphanumeric string is to be converted. More specifically, for example, when the “conversion method” is “R24”, “R” corresponds to information on how to convert an alphanumeric string, and “24” is an alphanumeric string. This corresponds to information indicating which digit corresponds to the conversion target. In this case, “R” is information indicating replacement. "R24" indicates that the second and fourth digits from the left side of the alphanumeric string are to be exchanged.

Similarly, for example, if the “conversion method” is “A
In the case of "43", "A" is information indicating that addition is to be performed, and "A43" indicates that if the fourth digit from the left of the alphanumeric string is a numeral, 3 is added to the fourth digit, If the fourth digit is an alphabetic character, it indicates that the fourth digit is to be replaced with the corresponding alphabetic character after three in alphabetical order, and similarly, for example, when the “conversion method” is “S32”, , "S" are information indicating the subtraction. And "S32"
If the third digit from the left of the alphanumeric string is a digit, subtract 2 from the third digit, and if the third digit is an alphabet, the third letter in the alphabetical order It shows that it changes to.

Next, an example of conversion of an alphanumeric string by the "conversion method" will be described with reference to FIG. For example, if the random alphanumeric string issued by the authenticator is "3
625 ". In this case, the" conversion method "
Is "R13", the converted alphanumeric string is "2635" because the first and third digits from the left of "3625" are interchanged. Similarly, when the "conversion method" is "A36", 6 is added to the third digit from the left of "3625", and thus "3685". Therefore, in this case, the user inputs "3685" as the personal identification number and transmits the password, whereby the authenticating side determines that the user is a valid user.

In this case, the first "conversion method" and the second "conversion method" may be registered as the "conversion method". For example, the random alphanumeric string issued by the authentication side is “3625” and the first “conversion method”
Is "R13" and the second "conversion method" is "A36", the first "conversion method" uses "362"
5 ”is converted to“ 2635 ”, and according to the second pattern,
“2635” is converted to “2695”. Therefore, in this case, the user sets “269” as the password.
By inputting and transmitting 5 ″, the authenticating side determines that the user is a valid user.

Next, referring to FIG. 8, a description will be given of a conversion example in a case where an alphabetic portion of an alphanumeric string is converted. For example, if the random alphanumeric string issued by the authenticator is "3
B25T8 ". In this case, if the" conversion method "is" A26 ", the converted alphanumeric string is the alphabetical character" B "in the second digit from the left of" 3B25T8 ".
Is converted to the corresponding alphabetical character "H" six characters later in the alphabetical order, so that "3H25T8" is obtained. Therefore, in this case, the user enters “3H25T8” as the password.
Is input and transmitted, the authenticating side determines that the user is a valid user.

If overflow occurs when adding numbers, the overflowed portion is not considered. For example, when "4" is added to "8", "12"
Is treated as “2”. Further, when the number is subtracted and becomes negative, the minus sign is not considered. For example, when "5" is subtracted from "2", it becomes "-3" but is treated as "3". In the case where alphabetic characters are to be converted backward in alphabetical order, if "Z" and subsequent characters are required, "Z" is counted again in alphabetical order from "A" after "Z". For example, an alphabetic character corresponding to four characters in alphabetical order after “Y” is handled as “C”. When converting alphabetic characters forward in alphabetical order, "A"
If the previous is required, "A" is followed by "Z" again.
From the alphabet. For example,
The alphabetic character corresponding to four alphabetically before “C” is treated as “Y”.

[2] Configuration of Embodiment [2.1] Configuration of CD (Cash Dispenser) Authentication System Referring to FIG. 1, the configuration of a CD authentication system according to an embodiment of the present invention will be described. As shown in FIG. 1, the CD authentication system 1 includes a CD terminal 10, a network 20,
An authentication device 30 is provided.

Here, the CD terminal 10 is a cash dispenser in a financial institution such as a bank. The authentication device 30 is a device that determines whether the user of the CD terminal 10 is a valid user. Many CD terminals 10 are connected to the authentication device 30 via a network 20 such as a dedicated line.

[2.2] Configuration of CD Terminal Next, the hardware configuration of the CD terminal 10 will be described with reference to FIG. CPU (Central Processing Unit) 11
Are ROM (Read Only Memory) 12 and RAM (Random
Access Memory 13 or HDD (Hard Disk Driv)
e) By executing various programs stored in 14, each unit of the device connected via the bus (BUS) 17 is controlled. The ROM 12 stores various programs executed by the CPU 11, control data, and the like. The RAM 13 is used as a work area of the CPU 11. For example, the RAM 13 has an HD
An execution portion of the application program stored in D14 and data used when the application program is executed are temporarily stored.

The HDD 14 stores various application programs. As this application program, for example, there is an application program for displaying an operation procedure when paying cash to a user. The communication control unit 15 includes a connection interface with the network 20 and a communication control circuit, and performs data communication with the authentication device 30 via the network 20. The display operation unit 16 includes a touch panel displaying touch keys for inputting characters, numbers, operation instructions, and the like. The display operation unit 16 outputs an operation signal corresponding to the touch key operation to the CPU 11.

[2.3] Configuration of Authentication Apparatus Next, the hardware configuration of the authentication apparatus 30 will be described with reference to FIG. The CPU 31 executes various programs stored in the ROM 32, the RAM 33, or the HDD 34 to control each unit of the apparatus connected via the bus 38.

The ROM 32 stores various programs executed by the CPU 31, control data, and the like. The RAM 33 is used as a work area of the CPU 31. For example, the RAM 33 temporarily stores an execution portion of the application program stored in the HDD 34 and data used when the application program is executed. Communication control unit 3
Reference numeral 7 includes a connection interface with the network 20 and a communication control circuit, and performs data communication with the CD terminal 10 via the network 20.

The HDD 34 has a “conversion method” storage area 35.
And a program storage area 36. The “conversion method” storage area 35 is an area for storing a “conversion method” DB that stores information on the “conversion method”. In this “conversion method” DB, for example, as shown in FIG.
"Conversion method" information including an account number 35a, first "conversion method" information 35b, and second "conversion method" information 35c is stored. Here, the account number is an identifier assigned to identify the account opened by each user at the bank.

The "conversion method" information stored in the "conversion method" DB is generated when a user opens an account. Then, the first “conversion method” information 35b and the second
The “conversion method” specified by the user when opening the account is registered in the “conversion method” information 35c. The first "conversion method" information 35b and the second "conversion method" information 35
c may be changed by the user after registration.
The program storage area 36 stores various application programs.

[3] Operation of Embodiment [3.1] Operation for Registering “Conversion Method” Next, referring to FIG. 9, the “conversion method” used in the CD authentication system according to the embodiment will be described. An operation example at the time of registration will be described. First, as shown in FIG. 9, for example, the user accesses a registration Web page for registering the “conversion method” from the personal computer terminal 40 owned by the user. The server device 50 storing the “conversion method” registration Web page transmits data for displaying the “conversion method” registration screen to the personal computer terminal 40.

The user inputs the user's account number and the desired "conversion method" on the registration screen displayed on the personal computer terminal 40, and executes the registration process (step S2).
1). At this time, the user inputs the “conversion method” desired by the user according to the input procedure of the “conversion method” entered on the registration screen. The server device 50 registers the account number and the “conversion method” received from the personal computer terminal 40 in the “conversion method” DB of the authentication device 30 (step S22). The server device 50 transmits a notification to the effect that registration of the “conversion method” has been completed to the personal computer terminal 40.

The method of registering the "conversion method" is not limited to this operation. For example, a user mails a "conversion method" registration form in which the account number and the "conversion method" are entered to the system administrator. Alternatively, the system administrator may register the “conversion method” entered on this sheet in the “conversion method” DB.

[3.2] Operation at the time of authenticating the user's legitimacy Next, with reference to FIG. 5, an operation example at the time of authenticating the user's legitimacy performed in the CD authentication system according to the embodiment will be described. explain. First, as shown in FIG. 5, for example, it is assumed that an item for withdrawing cash is selected from the transaction menu screen displayed on the display operation unit 16 of the CD terminal 10 and a cash card is inserted, for example. In this case, the CPU 11 of the CD terminal 10
The account information such as the account number stored in the inserted cash card is read. Then, in addition to the account information, the CPU 11 transmits a request signal for requesting cash withdrawal processing to the authentication device 30 (step S).
1).

The CPU of the authentication device 30 that has received the request signal
31 randomly issues a four-digit alphanumeric string in order to authenticate the user operating the CD terminal 10 (step S2). Here, for example, the CPU 3 of the authentication device 30
Assume that the four-digit alphanumeric string issued for No. 1 is "2G5M". When issuing an alphanumeric string, do not include the same duplicate alphabetic characters or numbers in the alphanumeric string. This is because, if the same alphabetic character or numeral is replaced, the same alphanumeric string is obtained before and after the conversion, and the function as a password will not work. And C
PU31 is the issued 4-digit alphanumeric string “2G5
M "to the CD terminal 10 (step S
3).

The CPU 11 of the CD terminal 10
"2G5M" received from 0 is displayed on the display / operation unit 16, and a request is made to input an alphanumeric string determined based on the alphanumeric string as a password (step S4).
Next, the user converts the “2G5M” based on the first “conversion method” “R34” and the second “conversion method” “A31” registered in advance, for example, to become the alphanumeric string “2G5M”.
In this case, the CPU 11 of the CD terminal 10 transmits the input alphanumeric string “2GN5” to the authentication device 30 (step S).
5)

The CPU 31 of the authentication device 30 that has received the alphanumeric string “2GN5” searches the “conversion method” DB based on the account number received from the CD terminal 10. And C
PU 31 performs the first “conversion method” corresponding to this account number.
The information 35b and the second "conversion method" information 35c are extracted (step S6). Here, for example, it is assumed that the CPU 31 extracts “R34” as the content of the first “conversion method” information and “A31” as the content of the second “conversion method” information. Next, the CPU 31 of the authentication device 30 converts the 4-digit alphanumeric string “2G5M” issued to the user based on the extracted first “conversion method” “R34” and the second “conversion method” “A31”. (Step S7).

This conversion will be specifically described. First, CP
U31 is based on the first “conversion method” “R34”,
"2G5M" is converted. In this case, the first “conversion method” indicates that the third and fourth digits of the alphanumeric string are exchanged. Therefore, the CPU 31 converts the third digit and the fourth digit from the left side of “2G5M” into “2GM5”. Next, the CPU 31 executes the second “conversion method” “A3
“2GM5” is converted based on “1.” In this case, the second “conversion method” is to convert the third letter from the left of the alphanumeric string to the corresponding letter in the alphabetical order. Is shown. Therefore, the CPU 31 sets “2GM
The alphabetical letter "M" in the third digit from the left of "5" is converted to the corresponding alphabetical letter "N" immediately after in alphabetical order, and "2GN"
Convert to 5 ".

Next, the CPU 31 of the authentication device 30 converts the alphanumeric string converted based on the first "conversion method" and the second "conversion method" in step S7 and the alphanumeric character string transmitted from the CD terminal in step S5. A comparison is made with the columns to determine whether they match (step S8). Step S8
If it is determined that the two alphanumeric strings do not match (step S8; NO), the CPU of the authentication device 30
31 sends a message prompting you to re-enter your password
The message is transmitted to the terminal 10 (step S9). here,
In this embodiment, the number of re-inputs is limited to an upper limit (for example, three times) so that the security level is not reduced.
Is set. On the other hand, in the determination of step S8,
If it is determined that the two alphanumeric strings match (step S
8; YES), the CPU 31 of the authentication device 30 recognizes that the user operating the CD terminal 10 is a legitimate user and issues a message requesting the input of the withdrawal amount to C.
It transmits to D terminal 10 (step S10).

In this operation example, the alphanumeric string converted based on the first "conversion method" and the second "conversion method" in step S7 is "2GN5", and transmitted from the CD terminal in step S5. If the alphanumeric string is "2
GN5 ″, the two alphanumeric strings match. Therefore, the user is authenticated as a legitimate user, and can continue withdrawing cash.

The method of realizing various functions of the authentication device according to the present embodiment is realized by storing in advance in the authentication device 30 a program for executing various functions performed by the authentication device 30 in this operation example. It is not limited to the case.
For example, there may be a case where the program is read from a recording medium on which the program is recorded and then installed and realized, or a case where the program is downloaded to an authentication device through an electric communication line and then installed and realized.

[4] Effects of Embodiment As described above, in this embodiment, different alphanumeric strings are issued each time by the authentication device, so that the alphanumeric strings (passwords) input by the user are also different each time. It will be. Therefore, it is not possible to analogize the “conversion method” just by seeing the alphanumeric string input by the user by another person, so that unauthorized use by another person can be prevented.
Therefore, the security effect can be further improved as compared with the conventional security code system.

In the embodiment, since the conversion is performed using a plurality of "conversion methods", the alphanumeric string issued from the authentication device and the alphanumeric string (password) input by the user are used.
Even if both of the alphanumeric strings are seen by another person, it is difficult to analogize the "conversion method", so that unauthorized use by another person can be prevented. Therefore, the security effect can be further improved as compared with the conventional security code system.

[5] Modification of Embodiment [5.1] First Modification In the above-described embodiment, the C of the authentication device 30
Although the alphanumeric string issued by the PU 31 is converted based on the “conversion method” and the converted alphanumeric string is compared with the alphanumeric string received from the user, the authenticity of the user is authenticated. The authentication method is not limited to this embodiment. For example, the alphanumeric string received from the user is inversely converted based on the “conversion method”, and the alphanumeric string after the inverse conversion is compared with the alphanumeric string issued by the CPU 31 of the authentication device 30 to determine the validity of the user. Authentication may be performed.
Hereinafter, the configuration and operation of the CD authentication system in this modified example will be described.

First, the configurations of the CD authentication system, the CD terminal, and the authentication device according to the first modification are the same as the configuration diagrams shown in FIGS. 1 to 4. Therefore, description of each configuration is omitted. Next, an operation example of authenticating the validity of a user performed in the CD authentication system according to the first modification will be described with reference to FIG. Steps similar to those in the operation example of the embodiment shown in FIG. 5 are denoted by the same reference numerals, and detailed description thereof will be omitted.

First, for example, it is assumed that, in step S2, the 4-digit alphanumeric string issued to the CPU 31 of the authentication device 30 is "2G5M" as in the embodiment. Then, the CPU 31 transmits the issued four-digit alphanumeric string “2G5M” to the CD terminal 10 (step S3).

The CPU 11 of the CD terminal 10
"2G5M" received from 0 is displayed on the display / operation unit 16, and a request is made to input an alphanumeric string determined based on the alphanumeric string as a password (step S4).
Next, the user converts the “2G5M” based on the first “conversion method” “R34” and the second “conversion method” “A31” registered in advance, for example, to become the alphanumeric string “2G5M”.
In this case, the CPU 11 of the CD terminal 10 transmits the input alphanumeric string “2GN5” to the authentication device 30 (step S).
5)

Next, the CPU 31 of the authentication device 30 receiving the alphanumeric string “2GN5”, for example, outputs “R34” as the content of the first “conversion method” information and “A31” as the content of the second “conversion method” information. Is extracted (step S6). The CPU 31 of the authentication device 30 reversely converts the four-digit alphanumeric string “2GN5” received from the CD terminal 10 based on the extracted first “conversion method” “R34” and the second “conversion method” “A31”. (Step S
17).

This inverse conversion will be specifically described. First, C
PU31 is based on the second “conversion method” “A31”,
"2GN5" is inversely transformed. In this case, the second “conversion method” indicates that the third digit of the alphabet from the left side of the alphanumeric string is converted to the corresponding alphabet in the alphabetical order.
Therefore, the CPU 31 determines that “3GN5” is 3
The alphabetic character "N" in the digit is converted into the alphabetical character "M" corresponding to the preceding character in the alphabetical order, and is converted into "2GM5". Next, the CPU 31 inversely converts “2GM5” based on the first “conversion method” “R34”. In this case, the first
"Conversion method" indicates that the third and fourth digits from the left side of the alphanumeric string are interchanged. Therefore, the CPU 31
Swap the third and fourth digits from the left of “2GM5”
Convert to “2G5M”.

Next, the CPU 31 of the authentication device 30 determines whether the alphanumeric character string inversely converted based on the first “conversion method” and the second “conversion method” in step S17 is stored in step S2.
In step S18, it is compared with an alphanumeric string issued to the user to determine whether they match (step S18). Step S1
If it is determined in step 8 that the two alphanumeric strings do not match (step S18; NO), the C
The PU 31 transmits a message prompting re-input of the personal identification number to the CD terminal 10 (Step S9). On the other hand, if it is determined in step S18 that the two alphanumeric strings match (step S18; YES),
The CPU 31 of the authentication device 30 recognizes that the user operating the CD terminal 10 is a legitimate user, and sends a message to the CD terminal 10 requesting input of a withdrawal amount (step S10). .

In this modified example, the alphanumeric string inversely converted based on the first "conversion method" and the second "conversion method" in step S17 is "2G5M" and issued to the user in step S2. If the alphanumeric string is "2
G5M ", the two alphanumeric strings match. Therefore, the user is authenticated as a legitimate user and can continue withdrawing cash.

[5.2] Second Modification In the above-described operation for authenticating the user's validity, the conversion pattern extraction process (step S6) shown in FIG. 5 and the alphanumeric characters issued by the authentication device are used. Although the process of converting the columns (Step S7) is performed after receiving the converted alphanumeric strings from the user (Step S5), the order of the processes is not limited to this embodiment. For example, step S3
In, after sending the issued alphanumeric string to the user,
Conversion pattern extraction processing (step S6) and processing for converting an alphanumeric string issued by the authentication device (step S7)
After that, the converted alphanumeric string may be received from the user (step S5). In this case, it is possible to reduce the time from when the user inputs the alphanumeric string (password) to when the authentication result is displayed to the user.

[5.3] Third Modification In the above-described embodiment, two patterns of the first "conversion method" and the second "conversion method" are set as the "conversion method". The setting method of the “conversion method” is not limited to this embodiment. For example, it is possible to set up to the fifth “conversion method”, and the user can arbitrarily set how many “conversion methods” are set. This "conversion method" may be changed at any time by the user. This makes it possible to arbitrarily set the security level.

[5.4] Fourth Modification The "conversion method" is not limited to the "conversion method" described in the above embodiment. For example, a plurality of digits or all digits may be set as a conversion target, and a specified number may be added or subtracted from a number corresponding to the conversion target digit, or a conversion target digit may be selected. The alphabetical order may be changed back and forth by the number specified for the alphabetic character.

[5.5] Fifth Modification In the above-described embodiment, the present embodiment is used for user authentication when operating from a CD terminal installed in a financial institution or the like. However, the present invention is not limited to this. For example, it may be used for authentication when a user's personal computer terminal accesses a server device owned by a financial institution via the Internet and performs processing such as account transfer. Further, it may be used for authentication at a closed level in the terminal, such as when a program or the like stored in the terminal is activated. That is, the present invention can be applied to various personal authentications.

[0054]

As described above, according to the present invention, an authentication method with a higher security effect can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of a CD authentication system according to an embodiment.

FIG. 2 is a diagram illustrating a hardware configuration of the CD terminal shown in FIG. 1;

FIG. 3 is a diagram illustrating a hardware configuration of the authentication device shown in FIG. 1;

4 is a diagram exemplifying a file configuration of a “conversion method” DB stored in a “conversion method” storage area shown in FIG. 3;

FIG. 5 is a flowchart illustrating an operation example in the CD authentication system according to the embodiment;

FIG. 6 is a flowchart showing an operation example in a CD authentication system according to a modification.

FIG. 7 is a diagram showing an example of converting an alphanumeric string.

FIG. 8 is a diagram showing an example of converting an alphanumeric string.

FIG. 9 is a diagram illustrating an operation example when registering a “conversion method”;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... CD authentication system, 10 ... CD terminal, 11 ... CPU, 12 ... ROM, 13 ... RAM, 14 ... HDD, 15 ... Communication control part, 16 ... Display operation part, 17 ... Bus, 30 ... Authentication device, 31 ... CPU (presentation unit, reception unit, conversion unit, determination unit, inverse conversion unit), 32 ROM, 33 RAM, 34 HDD, 35 conversion area storage area, 36 program storage area, 37 communication control Department, 38 ... bus.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masatomi Shimada 1-9-1 Konan, Minato-ku, Tokyo NTT COMWARE CORPORATION F-term (reference) 5J104 AA07 AA16 EA03 EA08 KA01 NA05 PA10

Claims (10)

[Claims] 1. A step of issuing an arbitrary alphanumeric string and presenting the issued alphanumeric string to a user; receiving an alphanumeric string input by the user; and a conversion method registered in advance by the user. Converting the issued alphanumeric string based on: comparing the received alphanumeric string with the converted alphanumeric string to determine whether they match, And a step of determining that the user who has input the received alphanumeric string is a legitimate user when it is determined that the two alphanumeric strings match. 2. A step of issuing an arbitrary alphanumeric string and presenting the issued alphanumeric string to a user; a step of receiving an alphanumeric string input by the user; and a conversion method registered in advance by the user. Inversely converting the received alphanumeric string based on, and comparing the issued alphanumeric string with the inversely converted alphanumeric string to determine whether they match, Determining that the user who has input the received alphanumeric string is a valid user when it is determined that the two alphanumeric strings match in the determination. . 3. The authentication method according to claim 1 or 2, wherein the “conversion method” determines how to convert the alphanumeric string and what digit of the alphanumeric string is to be converted. An authentication method characterized by including information on whether or not to perform authentication. 4. A presentation unit for issuing an arbitrary alphanumeric string and presenting the issued alphanumeric string to a user; a receiving unit for receiving an alphanumeric string input by the user; A conversion unit that converts the issued alphanumeric string based on a conversion method, and compares the received alphanumeric string with the converted alphanumeric string to determine whether they match, A determining unit that determines that the user who has input the received alphanumeric string is a valid user when determining that the two alphanumeric strings match. 5. A presentation unit for issuing an arbitrary alphanumeric string and presenting the issued alphanumeric string to a user, a receiving unit for receiving an alphanumeric string input by the user, and a registration unit pre-registered by the user. An inverse conversion unit that performs an inverse conversion of the received alphanumeric string based on a conversion method; and compares the issued alphanumeric string with the inversely converted alphanumeric string to determine whether they match. A determination unit configured to determine that the user who has input the received alphanumeric string is a valid user, when determining that the two alphanumeric strings match. 6. The authentication device according to claim 4, wherein the “conversion method” is used to determine how to convert the alphanumeric string and to determine which digit of the alphanumeric string is to be converted. An authentication device characterized in that the authentication device includes information on whether or not to perform authentication. 7. A computer which issues an arbitrary alphanumeric string and presents the issued alphanumeric string to a user; a receiving means which receives an alphanumeric string input by the user; Conversion means for converting the issued alphanumeric string based on the registered conversion method; and comparing the received alphanumeric string with the converted alphanumeric string to determine whether they match. A recording medium on which is recorded a program for functioning as a judging means for judging that the user who has input the received alphanumeric string is a legitimate user when judging that the two alphanumeric strings match. 8. A computer which issues an arbitrary alphanumeric string and presents the issued alphanumeric string to a user; a receiving means which receives an alphanumeric string input by the user; Reverse conversion means for reversely converting the received alphanumeric string based on the registered conversion method; and comparing the issued alphanumeric string with the inversely converted alphanumeric string to determine whether they match. Determining whether the two alphanumeric strings match each other, and recording a program for causing the user who has input the received alphanumeric strings to function as a determination unit for determining that the user is a valid user. Medium. 9. A computer which issues an arbitrary alphanumeric string and presents the issued alphanumeric string to a user; a receiving means which receives an alphanumeric string input by the user; Conversion means for converting the issued alphanumeric string based on the registered conversion method; and comparing the received alphanumeric string with the converted alphanumeric string to determine whether they match. And a program for functioning as a judging means for judging that the user who has input the received alphanumeric string is a legitimate user when judging that the two alphanumeric strings match. 10. A computer which issues an arbitrary alphanumeric string and presents the issued alphanumeric string to a user; a receiving means which receives an alphanumeric string input by the user; Reverse conversion means for reversely converting the received alphanumeric string based on the registered conversion method; and comparing the issued alphanumeric string with the inversely converted alphanumeric string to determine whether they match. A program for functioning as a judging means for judging that the user who has input the received alphanumeric string is a valid user when judging that the two alphanumeric strings match.