S-Email:a Distributed End-To-End Secure E-Mail System

With the rapid development of Internet, email has become an indispensable service in people’s daily life. However, it presents many security problems with a convenient and efficient service nowadays, such as "prism door event". These safety incidents will have serious consequences for individuals or companies, it leads to users’ privacy information was peeping. Therefore, a wide variety of email security protection measures are putted forward by many experts and scholars. For example, the SSL and TLS security transport protocol, which are widely used by using encrypted transmission mode of information content to ensure the safety of the mail. However, email will be stored in the server eventually, visitors with high privileges will be able to know the email content of all the users, it threatens the security of mail storage server.According to the mail server storage security, this paper proposes a distributed and end-to-end mail system based on the traditional e-mail system. The main idea is:the sender split email into multiple parts before sending the mail, then send multiple sub mail into the recipient’s multiple recipient address by several mail server; recipient need to download multiple sub mail from different server, and merge the sub mail to restore the original message. Through the system to send messages are saved on different mail server, even the users who have high server permissions will not be able to get the whole email content. In this way, ensure the security of mail server storage.This paper designs a S-Email protocol, and constructs the overall system framework includes a variety of security function, realizes a split algorithm and merging algorithm based on split sequence. Using open source of python to write the mail client, and realized all the functions of the mail system.