【作者】 张德华；

【导师】 周一宇； 冯登国；

【作者基本信息】 国防科学技术大学 ， 信息与通信工程， 2007， 博士

【摘要】 点对点网络安全问题研究对于点对点网络的应用具有至关重要的意义。点对点网络具有动态、自主和离散的特点。这些特点使得点对点网络的安全解决方案面临新的挑战,一些传统的安全机制不再适用于点对点网络。为此本文从点对点网络的信任管理系统入于研究点对点网络的安全问题,这些研究包括四方面的内容:如何从点对点网络的安全需求定义出点对点网络的信任关系,如何增加信任管理系统表达能力以适应点对点网络的特点,如何实现点对点网络信任关系可证明分析,如何在点对点网络环境下实现和应用信任管理系统。本文对点对点网络安全问题的研究从网络攻击和网络应用安全需求两方面入手,分析出目前点对点网络存在网络攻击的本质原因,它和安全需求一样都与信任关系的确立有关。本文分析了为解决点对点网络安全问题,引入信任管理系统的必要性。并根据安全需求,给出了点对点网络的信任关系定义。本文重点研究了信任管理系统的设计实现和应用,提出了基于SPKI扩展的信任管理系统——ExSPKI系统。本文详细定义了ExSPKI的证书结构,信任关系描述和系统的执行机构。ExSPKI系统定义了强命名的操作,该操作修正了SPKI系统关于复合命名的安全隐患;ExSPKI引入了操作请求和操作响应的标准形式,它使ExSPKI可以统一的处理与信任管理相关的证书数据,提高了ExSPKI的实用性,并且为ExSPKI的形式化分析提供了便利。ExSPKI在授权和委托证书中增加了条件域,该域增强了ExSPKI的灵活性和描述能力。为了更为深入理解ExSPKI系统和对信任关系进行形式化分析,我们给出了ExSPKI基于模态逻辑的语义分析,重点是定义了限定委托的逻辑谓词和语义,并且针对Abadi研究中存在的不足提出了新的命名语义。我们设计了ExSPKI的逻辑系统,并基于该逻辑系统对ExSPKI进行了逻辑重建。通过对逻辑系统正确性的证明和对ExSPKI推理规则为逻辑系统定理的证明,保证了信任关系形式化分析的正确性。基于ExSPKI系统,本文提出了点对点网络的安全路由协议SRP2P和点对点网络安全结构SAP2P。为了便于以上协议和结构的实现和对网络系统进行信任关系的形式化逻辑分析,我们首先设计了安全管道协议。安全管道协议提供了消息和ExSPKI证书的安全传递管道,并且它使管道两端密钥所发布的ExSPKI证书得到确认,基于这一结果可以在形式化分析时,直接引用证书的内容。安全路由协议SRP2P使用ExSPKI所提供的信任关系定义和信任管理服务,对参与路由协议的节点资格进行审核,并在路由信息传递时发送资格证书,从而保证了路由信息的传递是在可信的对等点之间进行的。为了满足点对点网络应用的需要本文设计了新的安全结构SAP2P。该结构引入用户代理的概念,把用户与实际运行的系统隔开,适合了点对点网络动态、自主的特点。在系统中,由用户代理完成相关的操作,减少了用户信息的暴露和密钥的使用。通过SAP2P提供的一组基于ExSPKI的协议,可以保证认证和资源访问控制符合信任关系的约束。为了验证ExSPKI系统的有效性和执行效率,本文在JAVA环境下基于RMI接口和SSL协议实现了ExSPKI应用实例,其中RMI接口提供通信网支持,SSL提供安全管道支持。通过该实例,我们验证了ExSPKI的有效性,实验结果也表明证明序列缓冲技术可以提高ExSPKI的执行效率。同时本文还实现了JXTA平台上的SRP2P和SAP2P应用实例。本文的研究成果推进了信任管理系统的研究,并对点对点网络安全性的增强和点对点网络应用的实际开发提供有益的借鉴。更多还原

【Abstract】 Research on P2P (Peer-to-Peer) network plays a significantly important part in the security of P2P applications. P2P network is dynamic, independent and discrete. These features make the security solutions of P2P network confronted with new challenges. Some traditional security solutions are not adapted to P2P network. For this reason, this thesis starts the study of the security problems of P2P network with the trust management system. Thesis researches consist of four main parts, including: how to define the trust relationships in P2P network from the security requirements of P2P applications, how to enhance the expression ability to fit the features of P2P network and how to implement, how to give a provable analyse of the trust relationship and how to use the trust management system in P2P network.This thesis studies the research of security issues of P2P network with network attacks and security requirements of P2P applications, pointing out the fundamental causes of P2P network attack which are related with trust relationship like security requirements. This thesis analyses it necessary to solve the security issues of P2P network using trust management system, and gives the definition of trust relation in P2P network according to the security requirement.This thesis emphasizes the research of the design, implement and usage of trust management system, presenting the trust management system named ExSPKI based on the extension of SPKI. This thesis defines the forms of ExSPKI certificates, description of trust relationship and implementation framework. ExSPKI gives the definition of bound-naming which amend the security hidden trouble in the extended naming operation in SPKI; ExSPKI introduces the standard forms of request and response, which make the certificate data related with trust relationship to be deal with uniformly in ExSPKI; ExSPKI add the condition field in the authorization and delegation certificate, which enhance the agility and ability of description of ExSPKI.To study the characters of ExSPKI deeply and give the formalization analyzing of trust relation of a system, we give the semantic analyse based on modal logic in ExSPKI. We give the limited-delegation logic predication and the semantic of it. We also design the new naming semantic based on the mend of research by Abadi on authorization computation and SDSI’s naming semantic. We design the logic system of ExSPKI, and give the logic reconstructing of ExSPKI. We give the proof the correctness of the logic system and proof of the deducing rule in ExSPKI to be the theorem, which providing the logic foundation of the analyzing of the trust relation of a system. This thesis presents the security routing protocol SRP2P and security architecture SAP2P. To make the implementation and formalization analyzing of trust relationship easily, we design the security channel protocol. The security channel protocol provides the security channel transporting the messages and ExSPKI certificates.Based on ExSPKI, the security routing protocol SRP2P is presented. SRP2P using the trust relationship definition and trust management service looks through the qualification of joining the routing peers, which guarantees the routing message exchange between trusted peers.To fit the requirement of P2P applications, the new security architecture SAP2P is designed. The concept of user agent is using in SAP2P, which separates the user from the P2P application and satisfy the features of P2P network. Using user agent, the exposure of user’s information and the usage of user’s key is cut down. The authentication and resource access control are fit the restriction of trust relation, using the protocol in SAP2P.To validate the validity and the efficiency of ExSPKI, this thesis gives the implementation of ExSPKI in the circumstance of JAVA using RMI and SSL interface. Through the analyzing of the implementation result, we validate the validity of ExSPKI and draw the conclusion that the cache technology can improve the efficiency of ExSPKI. And the implementation of SRP2P and SAP2P based on JXTA is also presented.To summarize, researching results in this thesis have promoted researches of security issues of P2P network and provide a good way for the development of secure P2P network applications.更多还原