Technical Study On Encrypted Elecrypted Electronic Official Document Transmission System

Nowadays, information and the Internet technique penetrates into each field of the society. The government information systems also build up the network electronic document systems. But besides convenience and high effect, the insecurity of information transmission by network has become a serious problem that cannot be neglected. Therefore, it is a research topic with practical significance and urgency that how to ensure the security of electronic document transmission.Based on the summarization of correlation theories that include E-mail basic principle, work pattern, communication protocol and so on, in this thesis, standard of secure E-mail is investigated, and research status home and abroad is analysed. The existent E-mail secure standards PGP and S/MIME are studied. The advantages and disadvantage of them and the limitations of popularization are analysed.A method to solve electronic document encryption transmission is advanced and designed in this thesis. The method is based on the technique of appropriative hardware encryption module, PKI, code mechanism, intelligent electronic key and so on. It can achieve confidentiality and integrality in the process of electronic document transmission. It can also insure that the dispatcher has non-repudiation while sending E-mail, and insure identity validity of E-mail accepter as well as local-storage security of E-mail.According to design idea, a PKI platform system model is put up in the thesis. This model includes certificate administration (CA), central port mail dispatcher and receiver, client port, electronic coffer, and so on. Using SCB2 special encryption arithmetic , the system encrypt the mail with digital envelope technique. The user's private key is conserved in intelligent electronic key(USB Key) and it is convenient for users to take and use, and it ensures the data security.For the sake of validating the validity and feasibility of the solutions, the function of the system are tested. The security are evaluated, and the solutions are compared with other systems. The results indicate that this system can fulfill all the design requests and accord with market practice demands.Finally, the work of this thesis is summarized, the value of the investigation and other fields the task can be extended are pointed out. The shortage of the method and the working prospect in the future are also pointed out.