Patent ID: 8024567

Claim:
A method for authenticating a user who wants to use a certain service provided by a system of a service provider through a first communication channel, the system of the service provider performing the steps of: receiving an access request from a first terminal of the user through the first communication channel; receiving an address or number of a second terminal of the user through the first communication channel, wherein the second terminal is a mobile communication terminal; transferring data for user identification to said second terminal through a second communication channel, said data for user identification including a user identification code generated by the system of the service provider and address data for enabling the second terminal to send the user identification code back to the system of the service provider, wherein the second communication channel is a wireless network and the user identification code is transferred back to the system of the service provider upon the user pressing a send button on the second terminal; receiving the user identification code from the second terminal through the second communication channel, said user identification code having been transferred from the second terminal to the system of the service provider by using the address data; determining whether the user identification code transferred to the second terminal is identical to the user identification code received from the second terminal; generating a user authentication code if it is determined that both the user identification codes are identical to each other; and transferring the user authentication code from the system of the service provider to the first terminal through the first communication channel, wherein: the address data include a callback number or callback uniform resource locator (URL) of a system for user identification, and the data for user identification further include a prescribed identification symbol comprising a numeral, graphic image, or a special character such as an icon character, and the method further comprises the steps of: transferring the identification symbol to the first terminal through the first communication channel and controlling the identification symbol to be displayed on the first terminal; controlling the identification symbol to be displayed on the second terminal; and allowing the user to determine whether the identification symbol displayed on the first terminal is identical to the identification symbol displayed on the second terminal and receiving a user confirmation response from the user accordingly.