【作者】 余滨；

【导师】 李祥；

【作者基本信息】 贵州大学 ， 计算机软件与理论， 2006， 硕士

【摘要】 为用户提供安全可靠的保密通信是计算机网络安全最为重要的内容。目前采用的方法是使用密码技术实现数据的加密传输，这样在网络中传递的数据是被加密以后生成的密文，从而防止非法用户窃取信息，实现了数据在网络中的安全传递。现代密码体制中，数据加密方法主要有对称密码体制和公钥密码体制两种。对称密码体制中，加解密使用同一把密钥，或加解密密钥可以相互导出：公钥密码体制中，使用一对无法相互导出的密钥来实现加解密，公钥对外公开，一般用于数据加密，私钥由用户自己保管，一般用于数据解密。由于加解密的算法都是公开的，所以信息的保密性主要取决于密钥的安全性。而密钥的分配和管理在此起到了至关重要的作用。但无论是对称密码体制还是公钥密码体制，通常都需要引入一个可信的第三方来保管和分发密钥，通信双方进行保密通信之前，都必须先与它进行通信，从而获得会话密钥，然后通信双方之间才能进行数据的加密传输。这在一定程度上增加了网络的成本和负荷。基于这个原因，本文提出了一种基于移动Agent技术的数据加密传输方法。 移动Agent技术最早起源于人工智能(AI)，除了具备固有的自主性、智能性外，还具有可移动性的特点，正是因为如此，它更适合于分布式系统的实现，尤其是在Internet日益普及的今天，各种移动设备频繁访问网络，进行资料存取，为了提高操作的可靠性和降低网络负荷，使用移动agent技术将是未来分布式系统发展的一个方向。 本文的主要工作、技术难点与创新如下： 1、对agent的相关内容进行了概述，比较了移动agent技术与目前传统的分布式计算模式之间的异同，和移动agent应用于分布式系统中的优点： 2、讨论了移动agent现有的开发系统及采用的开发语言，并对agent的标准研究进行了介绍： 3、较详细的说明了一个用于开发移动agent系统的开发平台——IBM aglet，包括该平台的安装、配置以及aglet的设计要素和开发模式； 4、通过采用IBM公司移动agent平台Aglet来实现了一个基于移动Agent技术的加密传输系统。在该系统中采用了aglet设计模式中的任务模式(task)中的主从模式(Master-Slave)； 5、由主agent在本地端产生一对加／解密密钥对，并将加密密钥交由子agent，派遣其到远程机器进行资料采集，然后将采集到的资料加密后传回。当主agent接收到密文后，再使用之前生成的解密密钥进行解密； 6、整个通讯过程中，在网络上传递的仅仅是加密密钥与密文，即使被非法的第三方截获也无法破译，从而保证了数据的安全传输； 7、整个通讯过程的参与方只有sender和receiver两个直接通信方，没有引入可信的第三方作为密钥分发的中间人，从而减少了网络的通信量，节约了网络开销，提高了工作效率。更多还原

【Abstract】 It is very important for user to provide a secure and reliable communication channel. Currently, encrpytion tachniques is applied to encrypt data, which makes it impossible for invalid user to see the data, so that it can be safely transport in network. There are two methods ,symmetrical encryption and dissymmetrical encryption, in modern encryption system. The former’s keys appled to encrypt and decrypt can be same or deduced each other. But nor does the latter’s. In dissymmetrical encryption system, the encrypted key is public,but the decrypted key is private.The encrypted data can only be decrypted correspond to the match key. Encryption arithmatic usually is open, so the security of encrypted data mainly depend on that of key. This means how to save and distribute keys play a very important role to data transportation in network. Thus, it is necessary for both to introduce the third believable party to provide the service saving and distributing keys. But meanwhile it also add the network load and transportation cost. Our research hopes to discover a solution to make secure transportation of the data in network easier and more converient.Mobile agent technique originally derives from artificial intelligence (AI). The key properties of mobile agents are autonomy , intelligence and mobility. Because of these characters, mobile agent is more adaptive than other techniques in distributed system, .when more and more mobile equipment visit network, especially in internet.In order to add operation reliable and reduce network load, mobile agent technique will be a good choice in distribution system.In this thesis, a summary about mobile agent is introduced, including mobile agent’s characteristic, the differences between mobile agent and other distributed techniques, and develop system and language used to mobile agent, etc. Then, we give a presentation about a tool used develop mobile agent—IBM Aglet, such as how to install and configure, and its’ basic elements. Lastly, We used the IBM aglet mobile agent system to implement a data-encrtyped transportation system, adopted master-slaver pattern. In this system, the slaver agent with encrypted key was produced and dispatched to the remote machine to access some data by the master agent.When it finished its’ task ,the slaver will transport the result back.And the master receive and decrypt it in decrypted key. Because only encrypted key and data were transported in network in the whole process, if attacker acquire them , he can not decrypt them.. Moreover, without introducing the third reliable party , network load is reduced .transportation cost is decreased and work efficiency is added.更多还原