【作者】 杨雪涛；

【导师】 李涛；

【作者基本信息】 四川大学 ， 计算机软件与理论， 2003， 硕士

【摘要】 电子邮件是Internet上最大的应用。个人利用电子邮件传输私人信件，公司利用它传送商业计划及数据，政府利用它发送公文，……，电子邮件无处不在!然而遗憾的是，电子邮件的世界是明信片的世界。就像明信片后面的信息一样，机器与机器之间传输的信息都是公开和可获取的，机器旁的每个人都可以查看上面的内容。并且信件的内容可在不为人知的情况下被篡改，不怀好意的人还可以冒发邮件。由于缺乏功能完善的安全电子邮件系统，为避免邮件泄露国家机密，国内党政机关禁止任何与外界的电子邮件联系，极大地阻碍了电子政务/电子商务的推广，阻碍了我国的信息化进程。 本文实现了一个基于PKI体系、提供数据加密和数字签名服务的安全电子邮件系统——鸡毛信(V1.00.000)，在提供普通电子邮件客户端功能的基础上，提供了电子邮件的保密性、认证身份、完整性和不可否认性等安全邮件服务。还提出了多重邮件加密同时封存/开封技术、证书管理与地址簿管理一体化技术，完全达到了商用水平。 文中，首先介绍了密码学的基本理论；PKI、CA的相关知识以及电子邮件的相关协议和标准(SMTP、POP3、MIME和MOSS)，然后对目前流行的安全电子邮件方案(PGP、S/MIME等)作了分析和评价，最后讨论了鸡毛信的总体结构以及主要模块(证书管理、地址簿、收发邮件)的设计和实现。 本文的意义在于开发出了具有自主知识产权，没有安全后门(与采用国外安全产品相比)，具有高加密强度，适合于国内用户使用的安全电子邮件系统，有效地解决了传统电子邮件存在的若干安全性问题，对保障我国电子邮件通信安全具有重大意义。更多还原

【Abstract】 Now Email becomes the most used application on internet. People use it to transfer their private letters, companies use it to transfer their business plans and data, governments use it to transfer their document, etc. Email is everywhere! But just like the message on postcard, all the message of email is open and can be gotten while it being tranferd between machines. Everyone who nears by computer can see the email. Moreever, an email can be modified by someone but other people hardly know, somebody with malignity can send an email imitating another person. Because lacking of perfect secure email system, domestic govements are not permitted to use email to transfer message in case it was stealed, which block our country’s e-business/e-government affair’s popularization and information industry’s progress.This paper implements a secure Email System based on PKI which provids Digital Signature and Encryption, called as JIMAOXIN(V 1.00.000),.Base on normal email software’s characteristics, JIMAOXIN has the following important characteristics: confidentiality, authentication, message integrity assurance, and non-repudiation of origin. It originates two technics:multi-encrypting to email and integrating management of certification into management of directory inquiries It fully reaches the level of commerce.This paper introduces the basic theory of cryptography and knowledge of PKI&CA and some protocols of Email System, such as SMTP, POP3, MIME and MOSS. It analyses and evaluates some popular secure standards of Email. At last.The paper discusses the design and implementation of JIMAOXIN.JIMAOXIN has three notable characteristics: independent intellectual property, without network secure holes in contrast to products abroad and achieving high cryptographic level. It effectively solves several secure problems in traditional Email System. JIMAOXIN is suitable for domestic users. It has profound significance in guaranteeing our country’s communication security of email.更多还原