Using GSM SIM Authentication in VPNs

Abstract

With the growth of the Internet a lot of different services has emerged. These services are often accompanied by some kind of security system. Since most of these services are stand-alone systems, a whole range of different authentication systems have been developed. Each using one of several kinds of authentication, with one or more proofs of identity. The SIM card used in mobile phones is an identifying token, containing strong authentication mechanisms. If services could utilize the SIM for authentication it would provide both a more secure solution, in addition to increased simplicity for the user. This master thesis builds on a project that investigated how the security properties of a system can be improved by adding an extra factor to the authentication process - something the user has, or more specifically the GSM SIM card. That project concluded by suggesting an overall design for a VPN Authentication System based on the security mechanisms in GSM. This thesis continues that work by analyzing that design, and describing the implementation of a prototype utilizing the mechanisms available.