X-TM：一种基于XML的信任管理框架

在分析现有信任管理的基础上,结合科学数据网格项目需求,提出了一种基于XML的信任管理框架X-TM。该框架包含了一种基于XML的统一信任证和策略语言,以及完成验证TrustTicket与一致性验证器的信任管理执行器,其主要创新点为可扩展的策略语言和支持TrustTicket与策略缓存的信任管理执行器,具有灵活性和良好的可扩展性等特点。     

基于策略的移动设备安全应用框架

提出了一种基于策略的移动设备安全应用框架，该框架采用XML描述访问控制策略，并结合身份认证、信任连接等安全机制实现对设备自身资源以及设备对网络服务的安全访问，使得用户对移动设备的使用处于安全控制之下。     

行为驱动的基于角色的信任管理

给出了描述行为驱动的信任管理语言RT_B.将变量引入到角色中可以记录用户的累积行为状态;行为驱动的信任规则根据用户已发生的行为调整其在本信任域中被分配的角色;组合规则提高了信任判定的效率;信任策略更新规则允许信任域在系统状态发生变化时自动调整信任策略.描述了行为驱动的信任管理的实现框架,并讨论了优化实现的几种机制.     

基于XACML的Web服务信任协商方案

针对Web服务中首次建立双方信任的问题,提出一种基于XACML的Web服务信任协商建立方案。利用XACML访问控制构建信任模型,给出信任协商策略描述,建立起基于XACML的信任协商架构,利用XML加密和签名来保证端到端的安全,提高了相互信任和策略的安全性。     

自动信任协商中一种策略一致性管理方法

自动信任协商（ATN)是指通过暴露信任凭证与访问控制策略进行匹配以达到建立信任关系的目的。在开放的分布式环境中,策略一致性管理便于网络用户发现资源,并及时了解访问资源所需具备的条件。当前,自动信任协商中的策略一致性管理由资源方进行维护,这不利于资源被发现,限制了资源的共享,浪费了资源方宝贵的计算资源。针对这些问题,提出了一种有效的策略一致性管理方法。该方法设立可信第三方,使用LDAP协议集中管理资源方的访问控制策略,使用通用语言XML对策略进行描述,可有效检测与避免策略更新、删除等所带来的策略不一致问题。     

面向分布式证明的信任协商策略语言和方法

现有信任协商语言对复杂的访问控制策略和协商策略以及信任分布式证明方法的支持都不够全面.在RT(role-based trust-management)语言基础上提出一种面向信任分布式证明和协商的策略语言RTP(role-based trust proving),其特点是能够支持信任分布式证明方法,可以定义复杂角色,保护信任证敏感信息并能避免信任证盲目搜索.给出了RTP语言及其推理规则的语法语义描述,介绍了一种基于RTP语言的信任分布式证明协商示例算法.实验结果表明,该算法支持RTP语言的功能,且比传统信任协商方法有很大的性能提升.     

一种基于XKMS的电子商务信任模型

安全性是困扰电子商务的最大问题,解决的最好方法是找到一种有效的信任模型,使交易双方能够方便地建立安全信任机制.XML密钥管理规范XKMS是一种基于XML的公钥密码基础设施PKI,它具有XML的互操作性和PKI的安全性等特点,为网络应用提供了可以互操作的安全基础设施.阐述了XKMS的概念和基本组成,分析了XKMS的基本原理,并给出一种基于XKMS的电子商务信任模型.通过原型系统的验证表明,基于XKMS的信任模型在一定程度上能解决电子商务的安全问题.     

基于信任约束的用户安全管理

在开放的网格环境中,用户行为的动态性和不确定性,使得现有的基于证书的静态用户管理难以及时地将用户的恶意行为进行标识并对用户后续行为进行控制。针对该问题,提出一种基于信任约束的用户安全管理方法。该方法基于对用户信任计算的结果,根据用户信任等级的变化,建立用户信任黑名单和白名单;并基于用户信任等级与资产价值之间的关系,建立一种信任策略。实验结果表明,该方法建立的用户信任黑名单、白名单和信任策略,作为访问控制机制的一种动态信任约束,加强了对系统授权的约束,使得用户能够获得的访问能力与其历史行为相关联,加强了对用户行为的控制,提高系统安全。     

PKI网络信任模型的分析与研究

信任模型是整个网络安全体系的基础,决定了在网络上采用信任的形式与采用该形式带来的信任风险,并提供了建立和管理信任关系的框架。可见,对于信任模型的研究在网络安全中非常重要。文章着重分析了基于PKI的各类信任模型的信任机制、认证过程及其存在优缺点,指出了各类信任模型对网络信息安全产生影响的主要原因。通过总结与对比,指出了PKI信任模型的设计策略与发展趋势。     

一种自适应的信任协商协议*

在分析现有的信任管理技术和自动信任协商技术的基础上,分别提出了一种支持信任管理的协商策略和一种最优化的信任协商策略,在此基础上设计了一种自适应信任协商协议。该协议可以实现多协议协商,同时融合了信任管理和自动信任协商系统的优点,能够实现安全域内和跨安全域的信任协商功能,具有良好的可扩展性、灵活性和隐私保护。     

Modeling Trust Negotiation for Web Services

As Web services become more widely adopted, developers must cope with the complexity of evolving trust negotiation policies spanning numerous autonomous services. The Trust-Serv framework uses a state-machine-based modeling approach that supports life-cycle policy management and automated enforcement.     

基于风险的PKI交叉认证模型研究

探讨了传统的公钥体系结构(PublicKeyInfrastructure,PKI)的缺陷,从信任管理角度,在基于风险的数字证书认证框架基础上,提出了PKI交叉认证的实现模型。模型包括基于风险的信任管理体系结构,终端证书的信任值计算方法及其实现算法,以及证书信任策略。     

Policy Management for Secure Data Access Control in Vehicular Networks

The state-of-the-art research in vehicular network security does not address the need for low latency message access control in vehicular applications with tight connection time and message delay requirements. In existing security solutions, the major limitation is that no trust establishment mechanisms that adapt to rapidly changing scenarios and highly mobile environments (mainly because of key management delay, processing overhead, and changing communication peers). To address this issue, we present a policy management framework for secure data access control in vehicular networks. Our solution address two interrelated research areas to achieve efficiency and scalability for data access control and policy management in highly dynamic vehicular networks. The main contributions are in two-fold: (a) efficient key management and group-based policy enforcement using attribute-based cryptography; and (b) dynamic security policy management framework and methodology to manage credentials based on role, time, location and other situation dependent attributes. Our solution utilizes efficient attribute-based cryptography algorithm to achieve unprecedented speedups in message processing time to meet the real-time requirement. To demonstrate the effectiveness of our proposed solution, a systematic and comprehensive evaluation is produced to valid our proposed solution.     

Model-driven trust negotiation for Web services

Trust negotiation is an approach to access control whereby access is granted based on trust established in a negotiation between the service requester and the service provider. Trust negotiation systems avoid several problems facing traditional access control models such as DAC (discretionary access control) and MAC (mandatory access control). Another problem is that Web service providers often do not know requesters identities in advance because of the ubiquitousness of services. We describe Trust-Serv, a trust negotiation framework for Web services, which features a policy language based on state machines. It is supported by lifecycle management and automated runtime enforcement tools. Credential retrieval and validation in Trust-Serv rely on predefined Web services that provide interactions with attribute assertion authorities and public key infrastructure.     

安全组策略管理

安全组通信的前提是一致的安全策略。组安全策略描述成员的安全目标、能力和需求，进而规定安全组的行为、访问控制参数、密码机制等。本文研究安全组策略的管理，包括组策略的制定、协商以及翻译、执行。在策略生命周期的基础上，依据安全多播组模型，提出组策略管理模型，并描述策略服务器的设计实现。策略的表示采用组安全策略标记语言(GSPML)．能够支持组策略灵活的表示和协商。     

一个软件服务协同中的信任管理框架设计

Internet-based Web application systems are gradually built as software service coordination systems. In an open, dynamic and collaborative application environment, traditional methods assumed with closeness, centralization and independence are not able to cope with these security problems efficiently. Trust management is a new method for dealing with security issues of open, distributed network application system. However, the traditional policy-based trust management systems have some shortcomings, i.e. complex in policy making, unable to deal with negative se-curity credentials, etc. So, we design a trust management framework in combination with subjective trust model for software service coordination and security decision in Internet environment. This trust management framework has characteristics of operability, reasonability, and flexibility in policy setting.     

A trust negotiation system for digital library Web services

A scalable approach to trust negotiation is required in digital library (DL) environments that have large and dynamic user populations. In this paper we introduce Trust-Serv, a model-driven trust negotiation framework for Web services, and show how it can be used to effectively handle trust negotiation in DLs. The framework employs a model for trust negotiation based on state machines, extended with security abstractions. High-level specifications expressed with the state-machine-based model are then translated into formats suitable for automating the trust negotiation process. The proposed framework also supports negotiation policy lifecycle management, an important trait in the dynamic environments that characterize DLs. In particular, we present a set of policy change operations that enable the dynamic evolution of negotiation policies without disrupting ongoing negotiations. The proposed approach has been implemented as a container-centric mechanism that is transparent to the DL and to the developers of DL Web services, simplifying DL development and management as well as enabling scalable deployments.     

An innovative simulation environment for cross-domain policy enforcement

With the development of policy management systems, policy-based management has been introduced in cross-domain organization collaborations and system integrations. Theoretically, cross-domain policy enforcement is possible, but in reality different systems from different organizations or domains have very different high-level policy representations and low-level enforcement mechanisms, such as security policies and privacy configurations. To ensure the compatibility and enforceability of one policy set in another domain, a simulation environment is needed prior to actual policy deployment and enforcement code development. In most cases, we have to manually write enforcement codes for all organizations or domains involved in every collaboration activity, which is a huge task. The goal of this paper is to propose an enforcement architecture and develop a simulation framework for cross-domain policy enforcement. The entire environment is used to simulate the problem of enforcing policies across domain boundaries when permanent or temporary collaborations have to span multiple domains. The middleware derived from this simulation environment can also be used to generate policy enforcement components directly for permanent integration or temporary interaction. This middleware provides various functions to enforce policies automatically or semi-automatically across domains, such as collecting policies of each participant domain in a new collaboration, generating policy models for each domain, and mapping specific policy rules following these models to different enforcement mechanisms of participant domains.     

X-FEDERATE: a policy engineering framework for federated access management

Policy-based management (PBM) has been considered as a promising approach for design and enforcement of access management policies for distributed systems. The increasing shift toward federated information sharing in the organizational landscape, however, calls for revisiting current PBM approaches to satisfy the unique security requirements of the federated paradigm. This presents a twofold challenge for the design of a PBM approach, where, on the one hand, the policy must incorporate the access management needs of the individual systems, while, on the other hand, the policies across multiple systems must be designed in such a manner that they can be uniformly developed, deployed, and integrated within the federated system. In this paper, we analyze the impact of security management challenges on policy design and formulate a policy engineering methodology based on principles of software engineering to develop a PBM solution for federated systems. We present X-FEDERATE, a policy engineering framework for federated access management using an extension of the well-known role-based access control (RBAC) model. Our framework consists of an XML-based policy specification language, its UML-based meta-model, and an enforcement architecture. We provide a comparison of our framework with related approaches and highlight its significance for federated access management. The paper also presents a federation protocol and discusses a prototype of our framework that implements the protocol in a federated digital library environment.