User identity authentication method using one time pin and otp, authentication server and otp generator implementing the same

According to one embodiment of the present invention, provided is a user authentication method of an authentication server. The authentication method, performed by the authentication server, using the OTP, comprises the steps of: receiving a request for generating OPIN from a banking server or a user terminal; generating the OPIN through an OPIN generating algorithm on the basis of at least one among an OPIN generating key, the current time, trading information, and an institution code; transmitting the generated OPIN to the user terminal; performing the verification of the OPIN received from the user, and receiving an OTP from an OTP generator which generates an OTP only if a verification is successfully completed; and verifying whether the OTP is valid or not through an OTP verification algorithm on the basis of the OTP and at least one among an OTP generating key, the current time, trading information and the institution code. The present invention relates to a user authentication method using a one-time PIN and an OTP, an authentication server performing the same, and an OTP generator, and more specifically to a technology which improves safety by generating an OTP in an OTP generator only when a primary verification is completed through an OPIN generated in an authentication server.