Authentication device, authentication system, authentication method, program and recording medium

Abstract

To prevent an input password from being stolen by an invalid authentication device. An authentication device 10 for authenticating an inputter based on an input password accepted from the inputter is provided with a first input part 110 for allowing a first part of the input password to be inputted; a confirmation information output part 120 for outputting confirmation information known to the valid inputter in advance when the first part 10 is valid, the confirmation information indicating to the user that the authentication device is valid; a second input part 130 for allowing a second part following the first part of the input password to be inputted; and a determination part 140 for determining that the inputter is valid when the first part and the second part are valid.

1 . An authentication device for authenticating an inputter based on an input password accepted from the inputter, the authentication device comprising:
 a first input part for allowing the first part of the input password to be inputted;   a confirmation information output part for outputting confirmation information known to the valid inputter in advance when the first part is valid, the confirmation information indicating to the user that the authentication device is valid;   a second input part for allowing the second part of the input password to be inputted; and   a determination part for determining that the inputter is valid when the first part and the second part are valid.   
   
   
       2 . The authentication device according to  claim 1 ; wherein the first input part allows the first part to be inputted via buttons of a telephone set located remotely from the authentication device; and
 the confirmation information output part outputs the confirmation information as audio signals to the receiver of the telephone set.   
   
   
       3 . A mutual authentication service provider providing a mutual authentication service for authenticating an inputter based on an input password accepted from the inputter via a computer as well as allowing the inputter to authenticate validity of a service site providing a predetermined service; the mutual authentication service comprising:
 an input password obtaining step for obtaining a valid input password set by the valid inputter in advance;   a confirmation information obtaining step for obtaining confirmation information known to the valid inputter in advance and indicating to the valid inputter that the service site is valid;   a first input step for allowing the first part of the input password to be inputted;   a confirmation information outputting step for outputting the confirmation information when the first part is valid in comparison with the valid input password;   a second input step for allowing the second part of the input password to be inputted; and   a notification step for notifying the service site that the inputter is valid when the first part and the second part are valid.   
   
   
       4 . A program for causing a computer to function as a mutual authentication service provider providing a mutual authentication service for authenticating an inputter based on an input password accepted from the inputter as well as allowing the inputter to authenticate validity of a service site providing a predetermined service;
 the program causing the computer to function as:   an input password obtaining part for obtaining a valid input password set by the valid inputter in advance;   a confirmation information obtaining part for obtaining confirmation information known to the valid inputter in advance and indicating to the valid inputter that the service site is valid; a first input part for allowing the first part of the input password to be inputted;   a confirmation information outputting part for outputting the confirmation information when the first part is valid in comparison with the valid input password;   a second input part for allowing the second part of the input password to be inputted; and   a notification part for notifying the service site that the inputter is valid when the first part and the second part are valid.