SIM Based WLAN Authentication for Open Platforms

2. Overview of GSM SIM Based Authentication This paper discusses approaches to authenticating users with open platforms, such as notebook PCs, for WLAN access using SIM cards. Using SIM cards to authenticate WLAN access is desirable by wireless operators as this approach minimizes additional infrastructure investments since the existing authentication processes and equipment are re-used. This paper starts with an overview of the authentication methodology in today’s GSM networks. Applying the GSM authentication methodology in a WLAN environment is then discussed. Enabling use of open platforms in WLANs requires consideration of potential security threats to authentication data due to the presence of open pathways. These open pathways are illustrated and possible mitigation techniques are discussed. With the appropriate mitigation approaches, SIM based user authentication can be easily extended to the WLAN environment. 2.1. SIM Subscriber Identity Module The role of SIM in GSM networks is to ensure that only authorized users can access the network. In order to properly authenticate a user, it must be able to store data, guard against unauthorized access to the stored data, and execute a cryptographic algorithm under secure conditions. The SIM and mobile device is authenticated with a background system. The data transferred between the mobile station and base station across the air interface is encrypted. 2.2. SIM Authentication on GSM Networks