【作者】 张驰；

【导师】 吴清锋；

【作者基本信息】 厦门大学 ， 软件工程（专业学位）， 2017， 硕士

【摘要】 随着计算机网络和移动互联网的发展,即时通信系统(Instant Messenger,即IM)在人们生活工作中扮演着越来越重要的角色,政府、企业都需要使用即时通信软件来提高工作效率,降低运作成本。最早的即时通信软件能够实现互联网、局域网内的信息沟通、文件传输等功能。随着时代的发展,即时通信软件的功能越来越丰富,可以进行语音、视频聊天,群聊天以及分享心情等等。但是对软件安全性能的关注并没有跟上,用户信息遭到泄露,对即时通信行业造成不良影响,应引起我们的重视。不少企业开始加强对即时通信安全性的研究和开发。本论文就是着眼于此,对安全的IM系统进行设计与实现,以供学习借鉴。论文主要介绍了即时通信系统的发展、运行原理和存在的问题,在此基础上设计并实现一款基于DES和RSA加密技术的混合加密策略的即时通信系统。该系统可在不影响用户使用的前提下,形成良好的加密策略保证用户信息的安全。通过这种方式,旨在提高用户在网络中传输聊天消息和账号密码信息的安全性。通过加密的手段可以帮助用户抵御嗅探技术窃取用户信息,增加截取信息破译的难度,提高在网络上传递信息信的安全性。系统分为客户端和服务器端,利用Socket网络编程技术和加密技术,具体包含:注册与登录模块,好友添加和删除模块,群聊天和服务器管理等功能模块。该系统注重功能的简洁和信息的安全性,把信息安全视为用户的首要保障和迫切需要。论文遵循软件工程的规范,设计实现该系统。本论文的主要研究内容包括:1、对现有即时通信系统的功能和发展趋势进行研究,学习如QQ、MSN等软件的优势和思路,加深对即时通信原理和功能的理解。2、对系统进行可行性分析、功能分析和非功能分析等,以用例图、流程图等形式提出对象化需求分析,在研究加密的基础上,提出加强系统安全性的构想和设计方案。3、利用Spring、JDBC等技术设计并实现本系统所需的方法、接口、界面、数据库等各功能模块。4、搭建模拟局域网和客户机/服务器模式的系统环境,设计测试方案对系统进行功能测试和非功能测试,确定软件的功能是否实现,发现程序设计中完整性、安全性、稳定性等问题。更多还原

【Abstract】 With the development of computer and Internet,Instant Messenger(IIM)plays an increasingly important role in people’s lives.The government and enterprises need Instant Messenger to improve work efficiency and reduce costs.The earliest Instant Messenger can connect to the Internet,support information communication,file transfer and other functions.As time flows,IM got more and more functions,such as voice communication,sharing moods,group chat and so on,but the measures on security did not keep up.Users’ information was often compromised,which brought bad influence to the IM companies.Because of this situation,the dissertation focuses on how to improve the security of IM on design and implementation.The dissertation mainly introduces the development of IM system,operating principle and the existence problems.The theme of the dissertation is to design and implement an IM system based on hybrid encryption with DES and RS A.It can provide a good encryption strategy to ensure the security of user information without affecting the user’s use.In this way,to improve the security of user chat messages and account information through the network.By the way of encryption,it can help users avoid sniffing technology which steals user information through the Internet.Encryption also increases the difficulty of interception of information deciphering,improving the security of information during Internet transmission.The system is divided into two parts,Client and Server.It uses Socket network programming technology and encryption technology,including:registration and login module,friends add and delete modules,group chat modules,server management and other functional modules.The system focuses on the simplicity of the function and the security of information.It regards information security as the primary guarantee and urgent need for users5 concern.The dissertation follows the method of software engineering to design and implement the system.The main contents of this dissertation include:1.Finding out the functions and development trend of existing Instant Messenger,studying the advantages and principles of existing IM system,such as QQ,MSN.2.Carrying out feasibility analysis,function analysis and nonfunctional analysis of the system.Using UML case diagram and flow chart for requirements analysis to build a demand model.To put forward the idea and design of security IM system on the basis of learning Encryption.3.Using Spring Bean,JDBC,network programming and other technology to design and implement the IM system which includes interfaces,databases,encryption and other functional modules.4.A simulation test environment for C/S system testing was built.Test plan for functional testing and non-functional testing was put forward.To make a conclusion about whether the function of the software is up to the requirements analysis and to find out the programs of integrity,security,stability and other issues.更多还原