Design Of Distributed PKI Framework Based On P2P And Application In Instant Messaging

With the development of networking technology, networking applications based on Internet (for instance, e-commerce and e-government) pose new requirements to information security. Public Key Infrastructure (PKI) technology based on public-key cryptography theory is considered to be the most feasible and most effective method to solve information security problems in open networking environment. PKI build a strict authority system according to Certification Authority (CA). However, PKI trust model and public-key management system are not suitable for distributed network without central control. Thus trust management and access control will be a hotspot among distributed network.According to characteristics of distributed networks, we proposed an idea to build distributed Public Key Infrastructure framework based on peer-to-peer. We designed dynamic trust model to solve the problem of trust management through researching kinds of trust models. Much research is done on the dynamic management and calculation of trust degree and the protocol of searching and choosing certificate trust path. Through researching the public-key management method of PKI and PGP, we designed distributed PKI public-key management system, which contains the update, revocation of the user certificate. Users can ensure the certificate in effect through using user-defined certificate revocation list. At the same time, we simplified the distributed PKI framework, and applied in instant messaging (IM). We design the whole architecture of IM encrypted system and its separated function modules. IM encrypted system realized database function operating on the related xml files and it is implemented in JAVA technology.