Abstract:

Global mobility network (GLOMONET) is a useful network environment which allows a mobile user to access the services provided by his home network in a foreign network. In order to ensure the secure communications conducted over the GLOMONET, it is important to authenticate mobile users before providing services. Recently, due to the advantages of tamper-resistance and convenience in managing the password files, some secure authentication schemes based on smart cards are proposed. The article points out the security vulnerabilities in some schemes and proposes a modified user authentication scheme. The scheme adopts the elliptic curve encryption system and uses low-cost function such as one-way hash function and exclusive-OR operation, so it is more secure and it has smaller amounts of calculations and smaller storage spaces. It is more suitable for battery-powered mobile equipments. It only requires four information exchanges between user and two agents. It possesses important security attributes including single registration, user anonymity, and no password table. The scheme is proved that can resist various attacks such as replay attack, known-key attack, imitation attack, and inside attack.

Key words: roaming network, smart card, anonymity security