Extensible Authentication Protocol Method for GSM Subscriber Identity Module, or EAP-SIM, is an Extensible Authentication Protocol (EAP) mechanism for authentication and session key distribution using the Subscriber Identity Module (SIM) from the Global System for Mobile Communications (GSM). EAP-SIM is described in RFC 4186.
GSM cellular networks use a subscriber identity module (SIM) card to carry out user authentication. EAP-SIM use a SIM authentication algorithm between the client and an Authentication, Authorization and Accounting (AAA) server providing mutual authentication between the client and the network.
In EAP-SIM the communication between the SIM card and the Authentication Centre (AuC) replaces the need for a pre-established password between the client and the AAA server.
"AAA and Network Security for Mobile Access. RADIUS, DIAMETER, EAP, PKI and IP mobility". M Nakhjiri. John Wiley and Sons, Ltd.