The invention relates to an arrangement and a method for reliably identifying a user in a computer
system. The method utilizes a
mobile station for communicating with the
system. The method comprises generating a first one-time
password in the
mobile station by utilizing a known
algorithm on the basis of the identification number of the user, subscriber-specific identifier, device-specific identifier of the
mobile station, and time. The
password obtained and the subscriber-specific identifier of the user are encoded and transmitted to an
authentication server of the computer
system, comprising identifying the user on the basis of the subscriber-specific identifier, searching a
database for the personal identifier number of the user and the device-specific identifier of the mobile
station associated with the user, generating a second
password at the
authentication server by utilizing the same predetermined
algorithm on the basis of the
personal identification number of the user, subscriber-specific identifier, device-specific identifier of the mobile
station and time, comparing the first and the second passwords with each other at the
authentication server, and if the passwords match, enabling the telecommunication connection between the mobile
station and the computer system.