Research On The Information Security Firewall Of PDA Intelligent Terminal

Thanks for the fast innovation of intelligent handheld communication technologies for PDA and the World Wide Web, the cutting edge applications like handheld based web page browse and online shopping are leading people towards a much more flexible and interesting future, which enables people to enjoy the fast and convenient services brought by the World Wide Web; while at the same time, it is an absolute industrial trend that protector like information security firewall be installed on handheld terminals due to the out coming network security risk issues. While unfortunately, as a matter of fact, mature network information firewalls for intelligent handheld terminals are not seen in the market, for the reasons below:1. 3G network is not been commercial launched;2. It is still a difficult task to develop embedded applications for intelligent handheld terminals, which is limited by the related developing utilities.For the reasons above, a firewall solution for Windows Mobile based PDA is raised and given by this dissertation. The firewall application adopts encased package capture means on application layer, which uses Winsock 2 SPI[1](Service Provider Interface) to realize network firewall facilities. SPI is a new programming interface introduced by Windows Sockets 2.0, and by using this new technology, programmers are allowed to insert a new layer in Socket, which enables the functions as encased package capture , transmission quality control, extended TCP/IP protocol stack as well as URL filter and network security control.This dissertation covers from research meaning to the existing research situation globally. And it starts from intelligent handheld terminal OS and firewall technology, and introduces the network information security issues of PDA and the corresponding solution. Besides this, platform and technology of this information security firewall design are also introduced, and as a dedicated application for PDA, SPI based encased package capture is adopted after deep analyisis and comparison amaong SPI, TDI as well as NDIS, considering the unique features of PDA. Based on these fundamental understandings, this dissertation discussed the infrastructure and general architecture of this firewall application, and the design and realization of each functional module are expatiated in different chapters. And at last, optimized solution of this application is given by careful system test and analysis.