System and method for user authentication

A user authentication system, located on a recording medium, designed to arrange a plurality of pattern elements in a given pattern format so as to create a presentation pattern to be presented to a user subject to authentication, and apply a one-time-password derivation rule serving as a password of said user to certain ones of the pattern elements included in said presentation pattern at specific positions so as to create a one-time password, said user authentication system comprising:

• an authentication server for managing respective user IDs and passwords of users of the system;
• and
• an authentication-requesting client connected to said authentication server via a network, to serve as a terminal for allowing each of the users to request authentication therethrough,
• wherein said authentication server includes:
• a password storage section pre-storing the user IDs and the one-time-password derivation rules of the users in associated relation with each other on a user-by-user basis;
• pattern-seed-value generation means for generating, in accordance with a given generation rule, a pattern seed value adapted to be combined with one of the user IDs so as to allow a presentation pattern to be uniquely determined;
• user-ID receiving means for receiving the user ID of the user subject to authentication, from the authentication-requesting client of said user;
• and
• pattern-seed-value transmission means for transmitting said generated pattern seed value, to the authentication-requesting client of said user subject to authentication, and
• wherein said authentication-requesting client includes:
• user-ID input means for allowing the user to enter his/her user ID therefrom;
• user-ID transmission means for transmitting said entered user ID to said authentication server;
• pattern-seed-value receiving means for receiving the transmitted pattern seed value transmitted from said authentication server;
• pattern-element-sequence creation means for creating, based on said entered user ID and said received pattern seed value and in accordance with a given pattern-element-sequence creation rule, a pattern element sequence consisting of a set of pattern elements for forming a presentation pattern;
• pattern display means for arranging the pattern elements included in said created pattern element sequence, in said given pattern format, to create the presentation pattern, and displaying said created presentation pattern on a screen;
• one-time-password input means for allowing said user to enter therefrom a one-time password created as a result of applying said one-time-password derivation rule to the pattern elements included in said displayed presentation pattern;
• and
• one-time-password transmission means for transmitting said entered one-time password to said authentication server of the user subject to authentication,
• wherein said authentication server further includes:
• one-time-password receiving means for receiving said transmitted one-time password;
• verification-code creation means for creating a verification code as a result of applying the one-time-password derivation rule corresponding to said received user ID, to certain pattern elements included in a presentation pattern formed from a pattern element sequence which is created based on said received user ID and said transmitted pattern seed value and in accordance with said given pattern-element-sequence creation rule;
• and
• user authentication means for comparing said received one-time password with said created verification code, and successfully authenticating the user corresponding to said received user ID if they are identical to one another.