关键词: EAP-AKA, 3G, 无线局域网络, 串空间, 认证测试方法

Abstract: An improved method is proposed in order to solve problems of EAP-AKA protocol.It implements mutual authentication between 3G networks and WLAN access networks by adding shared keys，which can be proved through strand space model and authentication test，the protection to IMSI by transmitting the encrypted NAI and the secure updating of shared keys between users and 3G networks by introducing key updating strategy.

Key words: Extensible Authentication Protocol-Authentication and Key Agreement（EAP-AKA）, 3G, Wireless Local Area Network（WLAN）, strand space, authentication test