Dynamic Password Authentication Based Vpn

With the fast popularization of the Internet, more and more company and government hope to work through network. Because the network security of Internet is very weak, Virtual Private Network(VPN) emerges as the times require. VPN is a security technology with which private information can be transferred under open network safely. Along with the rapid development of Internet, E-business and E-government,VPN will become an important developing direction of the future network certainly.This thesis introduced the basic concept and technology of VPN firstly, and then entirely describes the IPSec protocol suite's major components, including AH,ESP, and IKE.Then we discuss Security Policy,Security Association,User-Kernel communication mechanism used by IPSec VPN. Basing on the discussion about the security architecture for IPSec, it finally analyses the implementation of of the IPSec VPN designed by the author in those aspects,such as key exchange protocol based on dynamic password authentication,improved user-kernel communication mechanism, flow of network of VPN.This paper mainly focuses on key exchange protocol based on dynamic password authentication, which can insure the security of both authentication and transportation of VPN system. Meanwhile, we improve User-Kernel communication mechanism, and implement basic network flow of VPN.The aim of the dissertation is to implement a safe VPN system which can provide both safe authentication and safe transportation without the help of Public Key Instrument. By using dynamic password, users can log on the VPN system, access local network resources simply and safely.