Abstract: At present, 3G and WLAN, two kinds of wireless communication technology is the most representative. But because of between the shortcomings and advantages, resulting in 3G and WLAN fusion network is being the focus of the industry and academia, but also one of the most attractive. 3G-WLAN network can make full use of their advantages, which are mutually complementary. Users can enjoy 3G network perfect roaming, authentication and accounting mechanism, also can enjoy high-speed data transmission rate in WLAN. So users not only to enjoy the service network quality, but also makes more use of cyber source. But 3G and WLAN fusion network also need to address security threats from two parties. Because of the difference of 3G and WLAN network security threats, their own safety solutions are also very different and how to solve the security threat fusion network is an urgent problem to be solved. This paper analyzed and studied the 802.11i and WAPI in the access security of authentication and key negotiation flexibility and draws their respective strengths. The 3G-WLAN fusion network EAP-AKA protocol analyze its loopholes and defects, then synthesize 802.11i and WAPI protocol security advantages, this paper proposes a new 3G-WLAN security access scheme of EAP-WPI. The new protocol uses EAP authentication framework package certification of 802.11i and ECDH key agreement algorithm of WAPI, to achieve the user terminal and the backend authentication server authentication interaction, highly secure key agreement, and the use of public key cryptography without certificates in the certification process from the deployment of the PKI burden and makes security analysis and simulation test, which show that the paper which has proposed the protocol has higher of the safety and efficiency.

Key words: 802.11i, WAPI, EAP authentication, ECDH key agreement