A security extension providing user anonymity and relaxed trust requirement in NON-3GPP access to the EPS

Abstract

Third Generation Partnership Project (3GPP) has standardized the Evolved Packet System (EPS) as a part of their Long Term Evolution System Architecture Evolution (LTE/SAE) initiative. In order to provide ubiquitous services to the subscribers and to facilitate interoperability, EPS supports multiple access technologies where both 3GPP and Non-3GPP defined access networks are allowed to connect to a common All-IP core network called the Evolved Packet Core (EPC). However, a factor that continues to limit this endeavor is the trust requirement with respect to the subscriber’s identity privacy. There are occasions during Non-3GPP access to the EPS when intermediary network elements like the access networks that may even belong to third party operators have to be confided with the subscriber’s permanent identity. In this paper, we propose a security extension that relaxes this requirement. Contrary to several other solutions proposed recently in this area, our solution can be adopted as an extension to the existing security mechanism. Moreover, it has to be implemented only at the operators level without imposing any change in the intermediary network elements. We also show that the extension meets its security goals through a formal analysis carried out using AUTLOG.