SIM-based authentication method capable of supporting inter-AP fast handover

An SIM-based authentication method, which performs authentication on mobile nodes and networks in a wireless local area network (WLAN) environment such that packets between a legal mobile node and a legal network are transmitted through the WLAN, the mobile node having at least one SIM and the WLAN having at least one access point (AP) to service the mobile node, an authentication server and a connected authentication center, the method comprising the steps:

• a network authentication random number generating step, in which the mobile node generates a network authentication random number for sending to the authentication center and computes a first signature response and a network authentication encryption key based on the network authentication random number;
• a network authentication signature response generating step, in which the authentication center computes a second signature response and a same network authentication encryption key based on the network authentication random number and sends the second signature response to the authentication server;
• a mobile node pre-authentication random number generating step, in which the authentication center generates one or more mobile node pre-authentication random numbers and corresponding signature responses for sending to the authentication sever and also generates a mobile node authentication encryption key corresponding to the mobile node authentication random number;
• a mobile node authentication random number selecting step, in which the authentication server selects one mobile node authentication random number and corresponding third signature response from the mobile node pre-authentication random numbers and corresponding signature responses, and sends the mobile node authentication random number and the second signature response to the mobile node;
• a network authentication step, in which the mobile node authenticates the network by comparing the second signature response with the first signature response;
• a mobile node authentication signature response generating step, in which the mobile node computes a fourth signature response and a same mobile node authentication encryption key based on the mobile node authentication random number, and sends the fourth signature response to the authentication server;
• and
• a mobile node authentication step, in which the authentication server authenticates the mobile node by comparing the fourth signature response with the third signature response.