US Patent 9137243 Authentication system and authentication method

An authentication system 1 that uses sound to transmit one-time password(s) may be equipped with portable terminal(s) 10, authentication terminal(s) 30, and authentication server(s) 50. Portable terminal 10 may be equipped with password generating unit(s) 21 which encrypt information including password generation user identifier(s) issued by authentication server(s) 50 and generate one-time password(s), encoding unit(s) 22 which encode one-time password(s) and generate baseband signal(s), carrier wave generating unit(s) 23 which generate carrier wave(s) in audible band(s), modulating unit(s) 25 which use baseband signal(s) to modulate carrier wave(s) and generate modulated signal(s), and speaker(s) 17 which transmit modulated signal(s) in the form of sound wave(s). One-time password(s) may be input as sound wave(s) from portable terminal(s) 10 to authentication terminal(s) 30.