说明：  本文首先阐述了电子邮件技术的相关协议，以及相关的编解码技术和安全问题，对电 子邮件传输的协议进行了研究，发现现有的POP3，SMTP/ESMTP协议的安全漏洞， 并对这些协议的安全漏洞进行了详细的分析，提出了自己的解决方案和建议。
(This article first set out the e-mail technology related agreements, as well as related codec technology and security issues, e-mail transmission protocol conducted a study and found that the existing POP3, SMTP/ESMTP protocol security vulnerabilities, and these agreements security vulnerabilities carried out a detailed analysis, put forward their solutions and recommendations.)