Abstract: A user authentication system 4 includes an authentication processing module 44, which authenticates a user terminal device 1 based on received account identification information and authentication information; a fraud determination module 48, which detects fraud in a login request from the user terminal device 1 based on the access history of the user terminal device 1; and a response control module 46, which allows the user of said user terminal device 1 to log in to a predetermined account if no fraud is detected in the login request and the user terminal device 1 has been authenticated, and, on the other hand, allows the user of said user terminal device 1 to log in to a dummy account in accordance with predetermined criteria if fraud is detected in the login request from the user terminal device 1.

Abstract: A password management system includes a character string conversion unit that converts an input character string to a character string different from the input character string using a predetermined arithmetic expression, the predetermined arithmetic expression being capable of giving a same converted result for a same character string and capable of converting a character string such that a plurality of original character string candidates exist for a converted character string; a password data storage unit that stores, for each user, a converted past password character string CPP that is a converted state of a past password character string PP of the user using the predetermined arithmetic expression and is different from the past password character string PP; and a strength determining unit that determines strength of a password.

Abstract: To prevent logins to illegitimate sites such as phishing sites, a terminal device according to an embodiment stores authentication information used for login to a destination site in a storage (the authentication information storage area) in association with the site, and determines whether authentication information corresponding to the authentication information input for login to the destination site is stored in the storage in association with a site different from the destination site. The terminal device performs a predetermined alert process in response to the determination that the corresponding authentication information is stored in association with the different site.

Abstract: A user authentication system 4 includes an authentication processing module 44, which authenticates a user terminal device 1 based on received account identification information and authentication information; a fraud determination module 48, which detects fraud in a login request from the user terminal device 1 based on the access history of the user terminal device 1; and a response control module 46, which allows the user of said user terminal device 1 to log in to a predetermined account if no fraud is detected in the login request and the user terminal device 1 has been authenticated, and, on the other hand, allows the user of said user terminal device 1 to log in to a dummy account in accordance with predetermined criteria if fraud is detected in the login request from the user terminal device 1.

Abstract: A password management system includes a character string conversion unit that converts an input character string to a character string different from the input character string using a predetermined arithmetic expression, the predetermined arithmetic expression being capable of giving a same converted result for a same character string and capable of converting a character string such that a plurality of original character string candidates exist for a converted character string; a password data storage unit that stores, for each user, a converted past password character string CPP that is a converted state of a past password character string PP of the user using the predetermined arithmetic expression and is different from the past password character string PP; and a strength determining unit that determines strength of a password.

Abstract: A server check system that checks a duplicated process of a server that performs a predetermined process in response to a request from a terminal device, includes a receiving unit that receives a request sent from the terminal device to the server when starting a checking; a sending unit that generates a predetermined number of requests by copying the request and sends the predetermined number of requests to the server at the same time; and a determining unit that obtains a processed result by the server based on the predetermined number of requests and determines whether a duplicated process occurs.

Abstract: One object is to restrain unauthorized logins without significantly reducing usability. In accordance with one aspect, a server device according to an embodiment includes: an information storage unit for storing information; a setting unit for setting a value conversion rule used for login authentication; an information generating unit for generating login authentication information in response to a display request for a login screen sent from a terminal device; a sending unit for sending login screen data for displaying the login screen on the terminal device; a receiving unit for receiving login information from the terminal device; a determination unit for determining whether a login is permitted based on the received login information; a monitoring unit for monitoring the situation of unauthorized logins to the server device; and a selection unit for selecting a candidate for a new value conversion rule in accordance with the situation of unauthorized logins.

Abstract: A server check system that checks a duplicated process of a server that performs a predetermined process in response to a request from a terminal device, includes a receiving unit that receives a request sent from the terminal device to the server when starting a checking; a sending unit that generates a predetermined number of requests by copying the request and sends the predetermined number of requests to the server at the same time; and a determining unit that obtains a processed result by the server based on the predetermined number of requests and determines whether a duplicated process occurs.

Abstract: One object is to restrain unauthorized logins without significantly reducing usability. In accordance with one aspect, a server device according to an embodiment includes: an information storage unit for storing information; a setting unit for setting a value conversion rule used for login authentication; an information generating unit for generating login authentication information in response to a display request for a login screen sent from a terminal device; a sending unit for sending login screen data for displaying the login screen on the terminal device; a receiving unit for receiving login information from the terminal device; a determination unit for determining whether a login is permitted based on the received login information; a monitoring unit for monitoring the situation of unauthorized logins to the server device; and a selection unit for selecting a candidate for a new value conversion rule in accordance with the situation of unauthorized logins.

Abstract: One object is to restrain unauthorized logins without significantly reducing usability. In accordance with one aspect, the server device according to an embodiment includes: an information storage unit for storing information; an information generating unit for generating login authentication information in response to a display request for a login screen sent from a terminal device; a sending unit for sending login screen data for displaying the login screen on the terminal device; a receiving unit for receiving login information from the terminal device; and a determination unit for determining whether a login is permitted based on the received login information. The login screen data includes an instruction for converting the login authentication information.

Abstract: An information managing unit (4) has an ID information storage (41) for receiving and storing ID information (11) from an RFID reader (2) for detecting, from an RFID tag (1) holding variable ID information (11), the ID information (11) and for updating and managing the stored ID information (11) in synchronization with the variable ID information (11) held by the RFID tag (1), by a predetermined method; an event detector (42) for detecting an event to be a trigger to notify another information managing unit (5) of the stored ID information (11); and an ID information requester (43) for, when the event is detected, notifying the other information managing unit (5) of the ID information (11), for acquiring the ID information (11) and managing unit information about the other information managing unit (5) from the other information managing unit (5), and for storing the acquired managing unit information in correspondence to the ID information (11) into the ID information storage (41).

Abstract: An information providing method, comprises receiving a receiver identifier and an encrypted transmitter identifier from a receiver receiving the encrypted transmitter identifier from a transmitter by a relay equipment, decrypting the encrypted transmitter identifier by the relay equipment, determining an information providing equipment providing transmitter information with respect to the transmitter based on a decryption result of the encrypted transmitter identifier by the relay equipment, requesting the transmitter information from the information providing equipment by the relay equipment, receiving the transmitter information from the information providing equipment by the relay equipment, and transmitting the transmitter information to the receiver by the relay equipment.