摘要：    即时通信系统是一种基于互联网，打破地域限制的聊天软件。基于互联网，使得即时通信系统变的方便快捷，同时，也使得即时通信系统面临严峻的通信安全问题。无论是设计上的安全级别较低，还是用户的防范知识缺乏，都使得即时通讯系统存在大量的安全隐患。19858
    目前，密码保护是最行之有效的解决方法。因此，本次设计主要以密码保护技术解决上述系统的通信安全问题。本次设计使用了TripleDES和RSA两种加密算法嵌套加密的方法。以此，达到高效并且安全的数据加密。设计采取DES加解密传输数据，RSA加解密DES密钥的方法，融合两种密钥算法的优点，达到最佳效果。
 本次设计借助Visual Studio 2013工具，采取C#语言编写。在设计完成后通过服务器监听测试，客户端连接测试，数据加解密测试。程序可以正常的运行，并且顺利对信息进行加密解密，完成通信。完成了设计之初的需求，达到了毕业设计的要求。
关键词：    即时通信；网络通信安全；加密；DES；RSA
Network Security Communication System
Abstract: Instant communication system is an Internet-based system, breaking the geographical restrictions chat software. Because Internet-based instant communication system becomes quicker and easier, while also making the instant communication system is facing severe communication safety issues. Whether it is a lower level of security design, or the user's lack of knowledge of prevention that have made a lot of security risks by using instant communication system.
    Currently, the password protection is the most effective solution. Therefore, the password protection technology designed to solve the major security issues of these systems of communication. The design uses two encryption algorithms TripleDES and RSA encryption method nesting, which achieves efficient and secure data encryption. The design takes DES encryption and decryption of transmission data, takes RSA encryption and decryption the key of DES. Two key advantages of fusion algorithms, to achieve the best results.
    The design uses Visual Studio 2013 development tools, written in C # language. After the design completed, it passed server-listening test, client-connecting test, data-encrypted and data-decrypted test. Program can run normally. It can encrypt and decrypt data for communication. It completed the demand of initial design, and reached the requirement of graduation design.
Keywords:    instant community; Network communication security; encryption; DES; RSA
目录
1    绪论    1
1.1    选题背景    1
1.1.1    课题的目的和意义    1
1.1.2    国内外研究水平    2
1.1.3    发展趋势    2
1.2    文献综述以及调研情况    3
1.2.1    文献综述    3
1.2.2    加密算法的介绍    3
1.2.3    加密算法的选择    4
2    分析    6
2.1    需求分析    6
2.2    设计思路    8
2.3    模块功能    9
2.3.1    通信模块    9
2.3.2    DES加密模块    10
2.3.3    RSA加密模块    13
3    设计    16
3.1    整体设计    16
3.2    详细设计    17
3.2.1    通信模块    17 TripleDES+RSA网络安全通信系统设计:http://www.751com.cn/jisuanji/lunwen_11404.html