【作者】 费巧玲；

【导师】 徐向阳；

【作者基本信息】 湖南大学 ， 计算机应用技术， 2006， 硕士

【摘要】 电子邮件是Internet上最重要的服务之一。随着网络的迅速发展,如今通过电子邮件进行信息交流,已经成为人们联系沟通的重要手段,然而,由于网络的开放性,在Internet网络上传输的电子邮件会受到各种各样的攻击。因此如何保障邮件服务的安全是一项非常重要的课题,多种电子邮件安全解决方案已被提出并在特定的领域中发挥作用。本文首先介绍了电子邮件的基本原理,包括其组成、工作模式、通信原理、通信协议等,分析了电子邮件系统面临的安全威胁,研究了现存电子邮件安全协议标准,重点对PGP和S/MIME这两个目前流行的邮件安全标准进行研究,通过这些研究发现现存的安全邮件解决方案都只对邮件体进行加密和签名。但电子邮件是由邮件头和邮件体两部分组成的,邮件头特别是其中的邮件主题以明文的形式在网络上传输存在一定的安全隐患。本文研究了PKI技术、安全套接层SSL协议和智能卡技术,并在此基础上提出了一种安全邮件解决方案,旨在解决以下问题:(1)邮件主题的保密性问题(2)邮件头的安全传输问题(3)密钥的安全管理问题接着,本文利用公司己有产品(华翔腾密钥管理中心)搭建PKI平台,设计并实现了该解决方案的一个系统模型,该模型包括安全电子邮件服务器和客户端。对邮件主题采用接收者的公钥进行加密,通过提供SSL SMTP, SSL POP3服务,一方面增强邮件体传输过程中的安全性,同时防止邮件头在传输过程中被偷窥和篡改。用户私钥保存在USB Key中,方便用户携带和使用。为了证明该解决方案的正确性,本文对系统模型进行了功能测试和性能测试,给出了测试结果,并对安全性能进行了评估。结果表明,本文提出的安全邮件解决方案,不但增强了邮件的安全性,而且损失的性能也是可以接受的。最后对本文工作进行了总结,指出了本课题的研究意义和应用领域,同时指出了该方案的不足和下一步的工作展望。更多还原

【Abstract】 Email is one of the most important services on Internet. With the rapid development of network, using email has become a main method of people’s communication. However, as a result of network openness, the email that transmitted on it can come under various attacks. Therefore how to prevent the email from all kinds of attacks is an important task. Several secure email solutions have been proposed and used in specific fields.Firstly, this paper introduces some email basic theory, including its composition, working pattern, transmission principle, protocols and so on. It analyses the attacks, which the email systems faced. And it studies some existing secure email protocols, especially PGP and S/MIME. Through these researches, we discover that all of them only secure email body, but not email header. But email header especially email subject transmits on Internet in plaintext, which exists certain security hidden dangers.Next, this paper studies the PKI technology, SSL protocol and smart card technology, and then put forward a security email solution, which solves some problems as follows:(1) Protect email subject secret(2) Realize email header safe transmission(3) Security keys managementThen, this paper uses existing products (Wallgreat KMC) to build a PKI platform, and realize a model for this solution, which includes a secure email server and an email client. For the model, email subject is encrypted with the receiver’s public key; email header is transmitted safely, and email body enhance security, through SSL SMTP, SSL POP3. Users’private key can be saved in USB Key, help users carry and use.In order to prove the feasibility of this solution, this paper puts forward some results of function and performance tests, and the appraisal of security. These results indicate that this security email solution, not only strengthened the mail security, but also the losed performance is acceptable.The last part is the conclusion, which includes the work summary, the significances, the application domains, some deficiencies of the solution and next research directions.更多还原