A Proposal Of Secure Mail System With Intelligence Based On The PGP Technology

With the fast development of the Internet in recent years, much more private information needed to be transferred on it. Since E-mail is the primary method of the information delivery on the Internet, its security becomes an important problem among many users and developers. In the circumstance of E-mail weakness and relevant product shortage, we are intended to develop a secure mail system which is suitable for the network.For these cases, firstly, we have developed a client application for E-mail security which is based on the PGP Software Development Kit (PGP SDK). This application has all the basic security functions such as encryption, decryption, signature and authentication to the message body and the attachment. Using the method of keys management and the web of trust model from the PGP, it provides services like message's security, message's integrity, the certification of the sender and receiver and the no-deny.Secondly, this paper places much emphasis on the research of the PGP technology, including the format of the PGP message, the theory of the PGP security services and its implementation, and the web of trust mode. What's more important, we made two improvements on the web of trust mode, trust evaluation and trust mode regulation.Thirdly, which is the most important part, this paper proposes a concept of intelligent E-mail processing. The intelligent E-mail processing, which is based on the packet filtering and protocol analysis, makes the encryption and signature intelligent. Users can set security rules for the E-mail message processing according to their needs, and the rules are stored in the database, which makes the system remember and do the job automatically next time.Lastly, after the analysis of the network circumstances and the users' needs, we design the architecture of the intelligent secure mail system. We divided the system into several modules: access control module, user interface module, secure services embedded module, keys management module, system initialization module and so on.