The Study And Application Of Certificate Authority

With the development of the Internet, E-Commerce has gone into our living. Although E-Commerce gives us much convenience, it brings us troublesome problems which traditional commerce has not. Inauthoritative entity can expose, modify message transfered by Internet. The entity in E-Commerce can repudiate his commercial behavior.The combination usage of asymmetric and symmetric algorithm can insure the integrity, confidentiality, non-repudiation of message which are need in E-Commerce. Digital certificate is an effectual measure. CA(Certificate authority) , as the trusted third part, is charged with entity authentication in E-Commerce. CA affirms the entity identity, then binds the entity's public key and the identity together by signing in the entity's certificate. The certificate is an identifier of entity in E-Commerce. When the entity uses his certificate, CA maintains the binding.This paper studies the authentication principle and the method of implementing the CA. In chapter 1, the paper introduces the state of E-Commerce, the recent study state of PKI, and the background of this project. In chapter 2, cryptography is introduced, including asymmetric algorithm, symmetric algorithm and other cryptography concept. In chapter 3, the paper introduces the concept of certificate and PKI. In chapter 4, the paper states the process of CA management for secret key and certificate, and corresponding technology. In chapter 5, the paper discusses the entrust model of CA. At last, in chapter 6, the paper introduces the implement process of a simple CA system. In the system, the usage of security EDI message transmission is considered.