【作者】 刘军；

【导师】 李喆；

【作者基本信息】 东北大学 ， 通信与信息系统， 2008， 博士

【摘要】 空间是继陆地、海洋和空中之后,人类又一新的活动与发展领域,在全球遥感、观测、信息传输和力量应用方面,具有巨大的社会、经济和军事价值,随着对空间资源的依赖性日益增加,世界各国都在积极发展自己的航天力量,谋求空间优势,空间信息网是连接陆海空天一体化信息系统的纽带,是一项战略性基础设施,它的建立和建成必将对我国综合国力的增强产生深远的影响。为适应我国航天事业在空间领域的发展,围绕建立高可靠空间安全信息网络体系的需求,立足于空间信息网自主运行和快速反应的特点,集中力量对空间信息网安全组网关键技术进行研究,并取得了如下创新性成果：(1)提出了空间信息网安全组网模型,针对MAC和路由两方面组网关键技术,通过对MAC层的攻击检测和通信行为监测进行节点的MAC层信誉评估,并以此为依据进行多令牌管理,实现安全、公平的介质访问控制；设计适合空间信息网特点的自适应、自配置、自管理、具有负载均衡能力的高效分布式路由协议,并为其建立基于信誉的主被动相结合的安全保障机制；充分挖掘网络层和MAC层的相关性,进行跨层联合优化,实现空间与临近空间协同组网及网络安全防护,使空间信息系统可以高效、安全的互联互通。(2)提出了空间信息网动态路由协议。依据空间信息网特点,充分利用卫星、空间站等航天器运行的规律性和可预知性,合理地划分时间周期,将空间信息网动态拓扑结构规约成按时间段分隔的一系列连续的相对静态拓扑,从而简化路由控制过程；采用静态配置与动态调整相结合的策略,以较低的开销实现适合空间信息网拓扑高动态变化、资源受限特点的自适应、自配置、自管理、具有负载均衡能力的高效分布式路由协议。使用网络模拟软件NS2在SUN工作站上搭建空间信息网仿真平台,对所提出的路由协议进行了仿真测试,结果表明：动态路由协议具有良好的负载均衡能力,有效地提高了重负载情况下的网络性能；具有良好的扩展性和鲁棒性,当网络规模增加和拓扑变化时,路由收敛迅速,开销增加不明显,网络平均吞吐率下降较小,有效地提高了网络的抗毁性和健壮性,具有良好的路由性能。(3)提出了基于信誉度的主被动相结合的路由安全保障机制。分析路由协议面临的安全威胁,研究纵深保护的安全配置,以信息的保护、监测、反应和恢复四个方面对路由安全实施动态保障。针对网络的脆弱性,建立空间节点信誉量化、计算、评估和交换机制,实现网络成员信誉的准确定义和精确量化；建立分布式入侵检测系统,通过移动代理进行网络联合检测提高检测的正确率并有效防止恶意节点的诬陷行为；建立重构自恢复机制,进行入侵反应,通过孤立、隔离、路由重构等手段消除入侵根源；建立安全机制分级运行模式,根据网络安全状况和安全要求,采用不同等级的安全策略,节省全网的计算与通信资源。对路由安全机制的仿真表明：安全保障机制能够提高空间信息网路由安全性,使其具有对特定攻击的免疫性及对各种攻击的快速检测、诊断、反应能力,具有良好安全防护性能,当遭到攻击时,重构自恢复机制能够迅速恢复网络性能,提高网络抗毁生存能力。(4)提出了具有安全性保障的介质访问控制协议。通过对MAC层的攻击检测和通信行为监测进行节点的信誉评估,并以此为依据进行多令牌管理,多个持有令牌的节点采用IEEE802.11 DCF方式共享信道,从而实现安全、公平的介质访问控制。对具有安全性保障的介质访问控制协议仿真表明：协议能够发现MAC层恶意行为并进行有效反制,促使网络节点遵守协议规则,提高了网络MAC层安全性,与路由安全机制一起提高了网络安全防护能力。(5)设计开发了具有自主知识产权的空间信息网安全组网原型实验系统。原型实验系统搭建在局域网之上,由控制中心和终端节点组成,通过在每个节点设置网络过滤器,利用控制中心的拓扑信息,有选择地控制数据包的接收、转发,强制两个原本直接通信的网络节点必须经过其它节点的路由才能进行通信,并仿真节点移动性,将单跳共享网络模拟成空间高动态多跳网络,建立空间信息网拓扑,实现对安全组网关键技术的演示验证。上述成果的取得,对于保证空间信息网的安全性、可靠性、抗毁性与健壮性具有重要意义。更多还原

【Abstract】 Space, together with land, ocean and air, is another field for human’s activities and development. Space is of great social, economic and military value in global remote sensing, observation, information transmission and power application. With the dependence on space resources increases, countries all over the world take active part in expanding their spaceflight force in order to gain the upper hand in space. The space information networks is a vital nexus between the integrated information systems of land, ocean, air and sky; it is a strategic infrastructure. The foundation and establishment of the space information networks must profoundly impact the comprehensive national strength of our country.In order to adapt the development of our country’s spaceflight cause to space, the technology of safely organizing network in the space information networks was focused on. The research, based on the demand of building the space information networks with high credibility and security, considering its characteristics of autonomous management and rapid reaction, has acquired the following innovative results.(1) Construction of a model for safely organizing network in space information networks. The model, combining key techniques in MAC and routing layers, assesses nodes’ reputation through attack detection and monitoring of communication in MAC layer, and the assessed reputation is a basis for multi-token management so that secure and fair media accessing control can be achieved. And then an efficient distributed routing protocol was designed to accommodate the characteristics of space information networks. This proposed routing protocol is self-adapted, self-configured, self-managed and is able to balance load. And also a security mechanism based on reputation combining active and passive method was designed for the routing protocol. Further more after fully taping the network layer and MAC layer’s correlation, a joint cross-layer optimization was done to realize cooperated network organization in space and near space so that the space information system can interconnect efficiently and safely.(2) Design of a dynamic routing protocol for space information networks. By make full use of feature that in space information networks the operations of satellites, space stations and other spacecraft are regular and predictable, a reasonable division of cycle time separated dynamic topology into a series of consecutive relatively static topology by the time in order to simplify the process of routing control. A policy that combines static configuration and dynamic adjustment was proposed to achieve the efficient distributed routing protocol with the abilities of self-adapting, self-configuring, self-managing and load balancing. The routing protocol can be implemented with comparably low cost and is suitable for space information networks features that topology is highly dynamically changed and resource is constrained.The software NS2 for network simulation built on SUN workstation was used as space information networks simulation platform to simulate the proposed routing protocol. The results show that the dynamic routing protocol can well balance load and effectively improve network performance under heavy traffic, at the same time, it is also scalable and robust because when the size of the network is enlarged or topology is changed, the routing protocol can rapid convergence while neither increase cost nor decrease throughput. The routing performance is outstanding, which enhance resistance and robustness of the network.(3) Design of a secure mechanism based on reputation combining active and passive method. Based on the analysis of security threats faced by routing protocol and research on security configuration with deep protection, the mechanism dynamically safeguards the security of routing protocol in each of the four aspects including information protecting, monitoring, reacting and resuming. Afterwards against the vulnerability of the network, a scheme for quantifying, computing, evaluating and exchanging reputation between spatial nodes was proposed to achieve accurate definition and precise quantization of reputation for nodes in network; A distributed intrusion detection system was constructed, in which mobile agents were used to increase the correct rate and prevent malicious acts of nodes through combined detection; A reconstruction and self-healing mechanism was proposed, which reacted to the invasion and eliminate the invasion root in the way of isolating and insulating the malicious nodes and reconstructing routing path; A security mechanism grading operation mode was established, which chose different levels of security strategy according to network security state and safety requirements so that the network could save its computation and communication resources.The simulation results of the proposed security mechanism for routing protocol show that it can enhance security of routing protocol of space information networks and make network immune to special attacks and enable network good safety performance with rapid detecting, diagnosing and reacting to various invasions. The experimental results also indicate that the reconstruction and self-healing mechanism can rapid restore the network performance and enhance resistance of network simultaneously. (4) Design of MAC protocol with protection of security. The assessing of nodes’ reputation is accomplished through attack detection and monitoring of communication in MAC layer, and the assessed reputation is used as a basis for multi-token management. A node possessed with several tokens can share the channel in the way as IEEE802.11 DCF, so that secure and fair media accessing control can be achieved.The simulation results show that the MAC protocol with protection of security can detect malicious behaviors in MAC layer and take effective counter accordingly. The proposed MAC protocol makes nodes comply with the rule so that it can improve the security in MAC layer and enhance the ability of network protection along with routing security mechanism.(5) Design and development of a prototype of safely organized space information networks system with independent intellectual property rights. The prototype experimental system is built on LAN, composed with a central controller and terminal nodes. Every node configured a net filter using topology information from central controller receives and relays data packets selectively. Two nodes which are able to directly connect can be forced to communicate through another node. In the simulation of mobility of nodes, the single-hop sharing network was treated as a highly dynamic spatial multi-hop network. A topology of space information networks was constructed and security networking key technologies were verified.Accordingly, it has a very important meaning of ensuring the security, dependability, destruction-resistance, and robust of the space information networks.更多还原