可扩展匿名通信系统的研究

【作者】 杨再晗；

【导师】 陈建二；

【作者基本信息】 中南大学 ， 计算机应用技术， 2004， 硕士

【摘要】 随着网络的不断普及和广泛应用，网络安全问题受到了人们越来越多的重视。匿名通信，因为其可以隐藏通信双方的身份和通信关系，成为了许多在线网络应用的基本要求和网络安全研究人员的研究热点。然而，目前匿名系统的研究主要是集中在匿名有效性的研究上，众多匿名原型系统实现中对匿名系统管理的附加开销考虑较少，从而影响了系统的可扩展性。 本文针对Crowds匿名系统存在的可扩展性方面的不足，设计与实现了一种可扩展匿名通信系统SCACS系统。系统采用分区管理的思想，将加入系统的用户分成小的组，每一个用户可以加入多个组，并在所加入的多个组中的用户中进行随机路由转发。提出了基于二维坐标空间的分区管理机制和基于一致映射的分区管理机制，通过它们对系统协议进行了详细描述，并定性的对比分析了两种机制的不同。采用基于二维坐标空间分区机制，对SCACS系统进行了系统实现，详细描述了各个模块的基本功能、实现步骤并进行了模拟测试。文章对SCACS系统的匿名有效性和系统附加开销也进行了定量分析。理论分析和模拟测试都表明，SCACS系统可以保持与原Crowds系统相当的匿名性，同时有效的减少了系统的附加开销，提高了系统有效性。当系统中的分组个数较多时，基于一致映射的分区管理机制可以更有效的帮助用户确定加入的分组，提高查找和更新效率。 文章最后对研究工作进行了总结，并阐明了进一步的研究计划。更多还原

【Abstract】 With the rapid growth and public acceptence of the Internet as a means of communication and information dissemination, concerns about privacy and security on the Internet have grown. Anonymous Communication, since it can protect the identities of the communication participants and hide their communication relationships, has become an essential requirement for many on-line Internet applications and one of the hot spots of research for the network security researchers. However, the research has mainly focued on the anonymous effectiveness, many anonymous communication systems pay little attention to the extra cost of system management and thus affect the scalability of the system.In order to improve the scalability of the anonymous communication system Crowds, this paper has put forward the design and implementation of an anonymous communication system: the SCACS system. The system stems from the divide-and-conquer approach that partitions the network into anonyizing cliques. Each user of the system can join in several of the cliques and initiates the establishment of a random path by selecting users from these cliques. The paper has brought forward two hashing and partition management mechanisms based on two different logical topologies and made qualitative comparisons between them. The two mechanisms are the partition management mechanism based on 2-dimensional coordinate space and the mechanism based on consistent hashing. For the SCACS system based on 2-dimensional coordinate space, the basic functions and implementation procedures of each module have been explained in detail and the system has been evaluated by simulation. The paper also makes quantitative analysis of anonymous effectiveness and the extra cost of system management. The results derived from both probability analysis and simulation test indicate that the new systems can keep almost the same anonymity degree as the original system while efficiently increasing the scalability of the system by decreasing the cost of management. When there are many cliques in the system, the mechanism based on cosistent hashing can help to determine in which cliques each user joins in a more effective mode and improve the efficiency of user location.Finally, the paper sums up the work during the design and development, and discusses the future work of research.更多还原