It is well accepted among scholars,especially scholars of cultural relics that the Suanshu Shu(Writtings on Reckoning) is an origin of the Nine Chapters of Mathematical Procedures.

On the Relation Between the Suanshu Shu and the Nine Chapters on Mathematical Procedures;

The digital certificate of contemporary medical equipment;

The Information safety technology centered on digital certificate;

A scheme of authorized devices accessible streaming media services based on digital certificate;

The identification authentication of online payment based on SET digital certification;

And then digital certification based USB Key authentication mode and its limitation were studied.

This paper introducs the PKI(public key Infrastructure),digital certification and RSA arithmetic to implement the double people or multi people digital signature,which can guarantee the safety of the data correspondence on Internet , the legality identity of the net users , the safety of the using of EC and electrical government affair

Application of PKI Digital Certificate in Web System;

Analysis and Utilization of X.509v3 certificate;

Research and Implement of Advanced Authentication System Based on Digital Certificate Technology;

Application of digital certificates based on PKI in time stamp service system;

Digital Certificates Experiment of Generality of Electronic Commerce;

Based on the secure requirement of open Internet,this paper introduced the cryptography principles of digital certificates and its specific application in the E-government affairs system.