Patent ID: 8352739

Claim:
In a key exchange method for mutual authentication at a subscriber station accessed to an authentication server through a wired/wireless communication, a two-factor authenticated key exchange method comprising: (a) the subscriber station during an idle time at which the subscriber station is not connected to the authentication server and before a protocol for authentication with the authentication server is performed generating a random number and precomputing a first predetermined value to use for authentication with the authentication server; (b) the subscriber station transmitting a key to the authentication server, the key being generated using an identifier of the subscriber station and a public key of the authentication server; (c) the subscriber station receiving a random number generated by the authentication server; (d) the subscriber station encrypting the first predetermined value using the received random number, a password predefined in the subscriber station, and a key stored in a token, and transmitting the encrypted first predetermined value and a generated authenticator of the subscriber to the authentication server; (e) the subscriber station receiving an authentication server's authenticator from the authentication server, wherein the authentication server authenticates the generated authenticator of the subscriber using the encrypted first predetermined value and generates the authentication server's authenticator when the authentication is successful; and (f) the subscriber station using a secret key and the password, authenticating the received authentication server's authenticator, and accepting the authentication server's authenticator when the authentication is successful, wherein the authentication server's authenticator is generated by the authentication server using the encrypted first predetermined value transmitted from the subscriber station, and wherein the subscriber station authenticates the authentication server's authenticator using the first predetermined value.