Contents I. Introduction
With the development of mobile network technology, especially the development of the 3G mobile network, smart mobile terminal and mobile application techniques, the demand for implementing service application by public mobile network is increasing strongly. Especially the Ministry of Public Security, Tax Authority and the Bureau of Customs take the advantage of mobile networks to carry out service application. And in the applications, the safety is highly required while exchanging and sharing the data with these departments’ internal private business network (Private network for public security, Private Network for Taxation and Private Network for Customs, etc.). And when smart terminal carries out service applications via the mobile network, it will face many security threats, mainly embodied in the eavesdropping and network attacks from wireless network transmission and public network accessing. These threats would lead to security risks of the information’s integrity and confidentiality during the accessing process. For such needs, various types of mobile security access system are proposed and put into use. There’re two typical security access solutions, one is the mobile operators’ wireless VPDN (Virtual Private Dial-up Network) [1],[2],[3],[4], and the other is SSL/IPSec [5], [6] based encryption transmission technology access solution. Wireless VPDN secure access program provided by mobile operators is a mobile office system platform program designed specifically for users to access the industry network, which increases the concept of wireless Internet based on the VPDN. With the carrying capability of high rate packet network, L2TP (Layer 2 Tunnel Protocol) tunneling protocol, and the corresponding authentication and authorization mechanisms, it builds virtual private dial-up network for users. But such solutions of encryption transmission are fragmented, and their intensity is bound with the operator’s capacity, and keys are provided and maintained by the operator, thus, there’s certain management risk to the users. But the self-built transmission security access system is a security solution with high intensity, which is based on IPSec VPN end to end encryption transmission technology, and can achieve secure transmission from the terminal to the internal private network.
