基于加密接入令牌的IGMP安全机制

在 IP组播中当前使用的组管理协议 IGMP不提供接入控制 ,任何端点用户可自由地加入组播组 ;此外 ,IGMP报文在传输时没有加密措施 ,无法保证其安全性 .因此 ,对 IGMP报文的认证和接入控制策略便成为亟待解决的重要课题 .在 IGMP报文后附加接入令牌的方法虽然可以解决 IGMP协议存在的一些安全问题 ,但其仍存在一些缺陷 .在此基础上 ,提出了一种加密接入令牌的方法 ,阐述了如何申请、产生、传输和使用令牌 .加密接入令牌可以安全的传输认证和接入控制信息 ,并且可以多次使用 ,不需要在用户和组播路由器之间建立安全关联 SA,提高了令牌的使用效率     

Sender access and data distribution control for inter-domain multicast groups

The classical IP multicast model makes it impossible to restrict the forwarded data to that originated by an authorized sender. Without effective sender access control, an adversary may exploit the existing IP multicast model, where a sender can send multicast data without prior authentication and authorization. Even a group key management protocol that efficiently distributes the encryption and the authentication keys to the receivers will not be able to prevent an adversary from spoofing the sender address or replaying any previously sent data and hence, flooding the Data Distribution Tree. This can create an efficient Denial of Service attack.In this paper, we propose an architecture for sender access control and data distribution control in inter-domain multicast groups. For sender access control, the Protocol for Carrying Authentication for Network Access, encapsulating Extensible Authentication Protocol packets, is used to authenticate a sender and to establish an IPsec Security Association between the sender and the Access Router to cryptographically authenticate each packet. This access control architecture is then extended to support inter-domain multicast groups by making use of Diameter agents. An inter-domain Data Distribution Tree (DDT) is distributed over different domains. Hence, sender access control will be meaningless without protecting the whole DDT. We have protected the DDT from several attacks generated by a compromised network entity by carrying the multicast data in one or a series of Multicast Security Associations (MSA). Two alternate solutions have been developed that detect and stop forwarding of any forged packet by utilizing multiple checkpoints in the DDT. The first method uses a centralized MSA for the whole DDT while the second method uses a number of small-sized MSAs. Next, the two methods have been compared with respect to different features, such as establishment and maintenance costs, delivery time, etc. The MSA method has been compared with Keyed HIP (KHIP), and we have established that MSA-based methods reasonably outperform KHIP. Finally, the security properties of MSA construction using the GDOI protocol have been validated using the AVISPA tool. Two attacks have been detected by AVISPA, which we have fixed by modifying the GDOI protocol. The security properties of the data transmission method through MSAs using the Authentication Header (AH) protocol have also been analyzed.     

EAP-IKEv2协议研究和安全分析

认证是无线局域网的一种最重要的服务。EAP-IKEv2是一个新的基于EAP协议的认证和密钥分配协议。该文详细分析了EAP-IKEv2协议的流程和安全性,并使用协议分析工具AVISPA验证了EAP-IKEv2安全性,结果说明EAP-IKEv2能够保证EAP客户端和认证服务器的双向认证。     

面向WLAN的移动IPv6 AAA系统研究与实现

针对无线局域网需要对移动IPv6的移动节点（MN）在数据链路层进行访问控制的特点,设计并实现一个支持移动漫游的认证、授权和记账（AAA）系统。该系统由支持802.1x协议的前台无线访问点（AP）、后台EAP认证服务器和Web记账管理服务器,以及在前台和后台之间传递AAA消息的Diameter对等端构成。系统支持多种EAP认证方式、管理域间漫游、以及按流量或时间记账等。     

异构网络切换中认证机制优化的研究

基于网络接入认证承协议与可扩展认证协议相结合的网络层认证架构,采用预认证与认证关联证书相结合,提出一种能够减少异构网络间切换中认证时延的网络层联合认证机制优化方法。通过与IEEE802.11i预认证、网络层辅助链路层预认证2种认证优化方法进行仿真比较,表明其有效降低异构网络间切换认证时延。     

IMS接入认证与密钥协商协议的优化方法

认证与密钥协商协议（AKA）协议作为通用移动通信系统（UMTS）网络的接入认证和密钥分配协议,依然被IP多媒体子系统（IMS）网络所采用,但具体流程有些改变。文章分析了IMS接入AKA的过程,指出其存在一定安全漏洞,如假P-CSCF诱骗攻击、IMPI的安全传输等．针对上述漏洞,文章利用共享密钥和公钥认证中心,设计了一种改进的认证与密钥协商优化方案．最后通过安全性分析证明了所提出的方案能有效提高IMS认证与密钥协商协议的安全性。     

Heterogeneous networking

In this article, security challenges related to a mobile heterogeneous networking environment, and the general access patterns are discussed. A novel, unified networking architecture that enables secure heterogeneous networking, both in terms of networks and user devices is discussed. A comprehensive security framework providing a generalized authentication scheme using the Extensible Authentication Protocol (EAP) is then presented, by taking into account existing methods for secure network and device access.     

真实源地址框架下的特定源组播接收者认证*

为了解决特定源组播接收者认证问题,在研究真实IPv6源地址验证体系结构的基础上,提出了一种该体系结构下的特定源组播接收者认证方案。该方案在与主机直连的路由器上加载了认证功能,能够对组播接收者的组播认证码进行认证,以此实现组播接收者的合法性验证,防止网络中组播服务盗用;设计了一种存储于三层交换机的组播端口列表,解决了同一局域网内组播接收者访问控制问题。通过仿真实验证明,该方案能够实现对组播接收者的认证功能,而且对组播效率影响不大。     

IP多点广播技术及应用

ＩＰ多点广播是一种新兴技术,它以传统的ＴＣＰ／ＩＰ网络为载体,具有一对多和多对多的数据交付能力,为网络实时多嫖体和批量数据传输提供了解决手段,该６文简要介绍了ＩＰ多点广播技术的产生、发展和应用,重点分析了它的工作机制,包括多点广播的地址构造,Ｉｎｔｅｒｎｅｔ组管理协议和路由技术。     

一种基于HASH函数的EAP认证协议①

随着安全认证技术的发展,网络认证已成为保障网络安全的重要环节。当前被广泛使用的IEEE802．1X是建立在可扩展认证协议（EAP）基础上的一种认证框架。EAP提供了许多认证协议,每个认证协议都有自身的优缺点。有些没有提供用户名的保护,有些没有提供双向认证;有些部署较困难等。针对上述缺陷,提出了一种基于哈希函数的认证协议。阐述了该协议的具体认证过程,并对其进行了安全性分析,最后与当前一些认证协议作了比较。     

组播用户安全管理系统设计与实现

为了克服IP组播模型的开放性,使得在现有互联网条件下能够为组播管理者提供用户对频道的访问控制,在原有安全组播模型的基础上,提出了一种基于IPv6网络环境的组播用户安全管理系统模型的设计方案。该方案采用钩子(hook)机制在接入路由器上挂载了认证与访问控制模块,任何想要监听组播流的用户,都要通过该模块进行身份认证与频道访问权限的判定,从而实现了基于频道的组播用户安全管理。并在教育科研骨干网中实验验证了该系统的身份认证和访问控制功能。     

PANA与Diameter协议结合的体系结构

通过分析Diameter协议和PANA在工作模式及协议结构方面的结合性,提出一套将两者结合使用的完整方案,包括两者结合点关键设备的体系结构和基于Open Diameter开源软件包的实现方法。实验结果证明,该方案可以满足网络系统对认证、授权、计费的复杂要求。     

Providing EAP-based Kerberos pre-authentication and advanced authorization for network federations

Kerberos is a well-known standard protocol which is becoming one of the most widely deployed for authentication and key distribution in application services. However, whereas service providers use the protocol to control their own subscribers, they do not widely deploy Kerberos infrastructures to handle subscribers coming from foreign domains, as happens in network federations. Instead, the deployment of Authentication, Authorization and Accounting (AAA) infrastructures has been preferred for that operation. Thus, the lack of a correct integration between these infrastructures and Kerberos limits the service access only to service provider's subscribers. To avoid this limitation, we design an architecture which integrates a Kerberos pre-authentication mechanism, based on the use of the Extensible Authentication Protocol (EAP), and advanced authorization, based on the standards SAML and XACML, to link the end user authentication and authorization performed through an AAA infrastructure with the delivery of Kerberos tickets in the service provider's domain. We detail the interfaces, protocols, operation and extensions required for our solution. Moreover, we discuss important aspects such as the implications on existing standards.     

PWLAN中802.1x认证的研究与实现

公共无线局域网(PWLAN)作为一种新的公共宽带移动数据接入业务,为公众提供便捷的无线上网服务。然而由于其数据传输链路在物理上的开放性,导致了比有线网络更严重的安全隐患。论述了基于802.1x协议的EAP认证协议及其实现技术,提出了在PWLAN中EAP认证的客户端、认证者端的设计和实现方案。测试结果证明该认证系统能有效地提高PWLAN的安全性。     

基于802．1x的无线园区网AAA系统的设计与实现

无线网接入安全是网络安全的重要课题之一。回顾了802．11i中采用的802．1xEAP认证技术,对无线园区网如何实现安全接入与认证进行深入研究,提出采用Free Radius实现AAA功能的无线网体系结构,实现了采用数字证书的EAP-TLS方式服务器和客户端双向认证,提高无线网安全,保护无线网资源。还对无线园区网采用802．IxEAP认证的几种方案进行了深入分析比较,对根据不同园区网应用环境选择适当EAP设计方案提出了建议。     

交换式以太网上的多播协议

目前,桌面会议、电子白板和视频广播等多播服务大都运行在局域网环境中,而绝大多数局域网结构,如以太网,都采用广播方式处理多播数据,对多播的支持有限.采用IGMP Snooping的方法,在二层交换机中设计一个基于VLAN和IGMP的多播协议,用于控制交换以太网中不断增长的IP多播流.描述了该协议的基本思想、语法和语义以及一个该协议验证和测试的过程.     

Out-of-band federated authentication for Kerberos based on PANA

Nowadays, network operators and educational and research communities are extending the access to their Internet application services to external end users by deploying, with other domains, the so-called identity federations. In these federations, end users use the identity and authentication credentials registered in their home organizations for accessing resources managed by a remote service provider. However, current identity federation solutions focus mainly on assisting network access and web services, while a significant number of services are left aside (e.g., SSH, FTP, Jabber, etc.). Taking advantage of the widespread adoption of Kerberos by current application services, this paper presents a solution to provide federated access to any kind of application service by using existing Authentication, Authorization and Accounting (AAA) infrastructures. The solution bootstraps a security association, in the service provider which enables the acquisition of a Kerberos credential to access the service. To link the end user authentication with the AAA infrastructure and the bootstrapping of the security association the solution uses the so-called Protocol for Carrying Authentication for Network Access (PANA).     

A network access control approach based on the AAA architecture and authorization attributes

Network access control mechanisms constitute an increasingly needed service, when communications are becoming more and more ubiquitous thanks to some technologies such as wireless networks or Mobile IP. This paper presents a particular scenario where access rules are based not only on the identity of the different users but also on authorization data related to those users. In order to accomplish this general goal, it will be necessary to add to the traditional system-specific services for authentication and authorization, and also some entities able to manage the information related to identity, roles and permissions. Network access will be based on the 802.1X framework and the Authentication, Authorization, and Accounting (AAA) architecture, as they constitute the basis for most of the existing proposals for limiting the access to a restricted network. These proposals will be extended making use of an authorization infrastructure based on SAML statements, the RBAC model, and XACML as the main language for expressing authorization policies. The solution that we present in this paper is a consequence of an exhaustive and non-trivial analysis of the different mechanisms that could be used to provide this kind of service. As we will see, the correct integration of these different mechanisms leads to the definition of a scalable and versatile network access control system which conforms to the guidelines outlined by the AAA initiative.     

网络层组播在大规模流媒体直播系统中的研究与实现*

组播可以有效实现多点之间通信,如何利用网络层组播技术实现流媒体直播系统,是当前的研究热点之一。基于MixCast模型,提出并实现了一种新的基于网络层的安全组播模型。针对当前组管理协议IGMP不提供接入控制,任何端点用户可自由地加入组播组,缺乏安全控制问题提出了依靠应用层单播对接收者认证,提出一种解决网络层组播的安全性问题和可控性问题的方法。实验结果表明,本系统具有良好的安全通信效率和可控性。     

因特网组管理协议IGMP研究

IGMP是组播实现中重要的组管理协议。分析了现有的三个版本的IGMP协议,研究了其工作原理、报文格式和协议特点,以及IGMPv3协议对源特定组播的支持。