中文摘要：

移动网络环境存在诸多安全威胁，为保证信息传输的安全性，该文讨论了移动环境下的安全威胁，实现了一个在移动环境下建立IPSec VPN连接的终端系统。该系统利用NDIS实现防火墙穿越，以保证IPSec数据包的正常传输。同时利用安全智能卡存储X．509证书，用于身份验证，防止非法用户的入侵。

英文摘要：

There are many security threats in the wireless network. To ensure data transfer, the paper discusses the security threats in the wireless network and implements a system to establish IPSec VPN connection on mobile phone. To ensure stable data transfer, this system implemented firewall acrossing with NDIS. It stores X.509 certificate on security smart card. This certificate is used to identify the user identity to prevent the inbreak of lawless user.