基于条件谓词逻辑的可信计算形式化分析

随着可信计算应用的不断发展,针对可信计算的形式化分析理论将成为可信计算领域研究的热点。在深入研究可信计算相关技术、信任链建立和信任传递过程影响因素的基础上,提出了基于条件谓词逻辑的可信计算形式化分析方法。通过定义不同的谓词和推演规则,并在谓词逻辑中添加可信性的影响因素作为约束条件,实现对可信计算信任模型的形式化验证。利用提出的方法举例对可信计算平台安全引导过程进行了分析,并且根据分析结果提出了委托受限的安全引导过程。结果表明,基于条件谓词逻辑的形式化验证方法,能够清晰、有效的实现对可信计算信任模型的形式化分析,为可信计算应用模型的设计和完善提供参考。形式化方法的提出,对于丰富可信计算信任评估理论,促进可信计算应用发展具有一定的意义。     

面向老人迟滞性特征的可信情感计算

根据老人认知心理特征中的迟滞性特征,结合基于Gross认知重评的情感计算模型,考虑迟滞性特征对个体情感状态转移的影响,在认知重评参数的基础上,建立迟滞性因子,对当前情感状态下的认知重评能力进行修正,从而对情感计算模型进行有效的修正,使人机交互更加自然和谐.为了实现情感计算模型的可信,结合现场可编程门阵列硬件平台和高级加密标准密码算法对情感计算模型中的老人情感信息进行加密处理,实现情感计算过程中的数据可信.采用可编程片上系统技术在现场可编程门阵列芯片EP4CE115F29C7中搭建功能实现所需的所有硬件组件,结合硬件组件编写逻辑程序并实现高级加密标准密码算法,在情感计算过程中实现数据的实时传输和安全处理,实现可信的情感计算.最后实验结果表明受到迟滞性特征影响下的情感计算模型与老人的真实情感具有高度一致性,且可信计算有助于提升老人的正向情感状态.     

基于服务端存储的可信计算模型

为了充分利用服务端存储模式计算机的非本地存储特性,该文提出了一种适用于服务端存储的可信计算模型。该模型通过把原有的可信平台模块硬件逻辑化为服务端软件模块,不仅降低了可信计算模型实施的难度,而且提高了其灵活性和扩展性。同时该模型从客户端系统的引导阶段出发构建完整的可信链,保证了可信计算平台的安全性。原型系统实现的结果表明:由于系统中所有客户端的信任度量均在服务端完成,使服务端能制定针对局域网全网的安全策略,进而实现真正的局域网网络可信。     

Trust Based Pervasive Computing

Pervasive computing environment is a distributed and mobile space. Trust relationship must be established and ensured between devices and the systems in the pervasive computing environment. The trusted computing （TC） technology introduced by trusted computing group is a distributed-system-wide approach to the provisions of integrity protection of resources. The TC＇s notion of trust and security can be described as conformed system behaviors of a platform environment such that the conformation can be attested to a remote challenger. In this paper the trust requirements in a pervasive/ubiquitous environment are analyzed. Then security schemes for the pervasive computing are proposed using primitives offered by TC technology.     

The theory and practice in the evolution of trusted computing

Trusted computing （TC） is an emerging tech- nology to enhance the security of various computing plat- forms by a dedicated secure chip （TPM/TCM）, which is widely accepted by both the industrial and academic world. This paper attempts to sketch the evolution of TC from the view of our theoretical and engineering work. In theory, we focus on protocol design and security analysis. We have proposed the first ECDAA protocol scheme based on q-SDH assumption, which highlights a new way to design direct anonymous attestation scheme. In technical evolu- tion, we discuss the key technologies of trust chain, trusted network connection and TC testing and evaluation. We break through several key technologies such as trusted boot, OS measurement and remote attestation, and imple- ment a TC system from TPM/TCM to network. We also design and implement a testing and evaluation system of TC platform, which is the first one put into practical application in China. Finally, with the rapid development of cloud computing and mobile applications, TC is moving toward some new directions, such as the trust in cloud and mobile environments, new TPM standard, and flexible trust execution environment trust establishment method.     

TPM context manager and dynamic configuration management for trusted virtualization platform

It is absolutely critical that trusted configuration management which significantly affects trust chain establishment, sealing storage and remote attestation, especially in trusted virtualization platform like Xen whose system configuration changes easily. TPM （trusted platform module） context manager is presented to carry out dynamic configuration management for virtual machine. It manages the TPM command requests and VM （virtual machine） configurations. The dynamic configuration representa- tion method based on Merkle hash tree is explicitly proposed against TCG （trusted computing group） static configuration representation. It reflects the true VM status in real time even if the configuration has changed, and it eliminates the invalidation of configuration representation, sealing storage and remote attestation. TPM context manager supports TCG storage protection, remote attestation etc, which greatly enhances the security on trusted virtualization platform.     

A Separated Domain-Based Kernel Model for Trusted Computing

This paper fist gives an investigation on trusted computing on mainstream operation system （OS）. Based on the observations, it is pointed out that Trusted Computing cannot be achieved due to the lack of separation mechanism of the components in mainstream OS. In order to provide a kind of separation mechanism, this paper proposes a separated domain-based kernel model （SDBKM）, and this model is verified by non-interference theory. By monitoring and simplifying the trust dependence between domains, this model can solve problems in trust measurement such as deny of service （DoS） attack, Host security, and reduce the overhead of measurement.     

Design and Implementation of a Bootstrap Trust Chain

The chain of trust in bootstrap process is the basis of whole system trust in the trusted computing group （TCG） definition. This paper presents a design and implementation of a bootstrap trust chain in PC based on the Windows and today＇s commodity hardware, merely depends on availability of an embedded security module （ESM）. ESM and security enhanced BIOS is the root of trust, PMBR （Pre-MBR） checks the integrity of boot data and Windows kernel, which is a checking agent stored in ESM. In the end, the paper analyzed the mathematic expression of the chain of trust and the runtime performance compared with the common booring process. The trust chain bootstrap greatly strengthens the security of personal computer system, and affects the runtime performance with only adding about 12% booting time.     

A cross-domain access control model based on trust measurement

Based on trust measurement, a new cross-domain access control model is proposed to improve the security performance of the cross-domain access control processes. This model integrates the trust management and trusted platform measurement, defines several concepts (user trust degree, platform configuration integrity and intra/inter-domain trust degree) and calculates them with users’ uniform identity authentication and historical access behavior analysis. Then this model expands the extensible access control markup language (XACML) model by adding inside trust manager point (ITMP) and outside trust manager point (OTMP), and describes the architectures and workflows of ITMP and OTMP in details. The experimental results show that this model can achieve more fine-grained access control, implement dynamic authorization in a simple way, and improve the security degrees of the cross-domain access control.     

基于信任模型的WSNs安全数据融合算法

为了抵御无线传感器网络内部的恶意攻击行为和故障节点的误操作行为对数据融合结果的影响,提出一种基于信任模型的多层不均匀分簇无线传感器网络安全数据融合算法.该算法基于多层不均匀的分簇网络拓扑实现安全数据融合能够有效均衡网络中节点的能耗.通过节点间的通信行为和数据相关性建立信任评估模型,并引入动态的信任整合机制和更新机制,实现簇内和簇间的信任评估,选择可信融合节点并将可信节点所收集的数据进行基于信任值加权的数据融合.仿真实验表明,该算法能够实现精确的信任评估,有效识别内部恶意攻击节点,得到的数据融合结果具有较高的精确度,实现了安全的数据融合.     

A Method to Implement Full Anonymous Attestation for Trusted Computing Platform

Trusted computing （TC） technology is brought out by trusted computing group （TCG） to make computing as safe and reliable as people expect. Attestation is one main function specified by TCG, which is the means by which a trusted computer assures a remote computer whose platform is not tampered with. There are two protocols that implement attestation without disclosing the platform＇s real identity, which are Privacy CA-based protocol and direct anonymous attestation （DAA） protocol. However, in the first protocol the privacy CA is the bottleneck and the platform＇s identity will be disclosed if the privacy CA is compromise, while DAA protocol can do profiling when dealing with rogue hardware device. In this paper, we propose a DAA-extended new approach to ensure full anonymous attestation that can not only detect a rogue TPM, but also reveal rogue TPM＇s real identity.     

基于群论的可信云计算平台的研究与改进

云计算能减少公司在网络服务上的投资成本,但同时也存在让公司担忧的问题:云端的用户数据安整性、用户网络连接的可信性、云服务商的保密性等可信问题。提出一种改进的可信云计算机平台设计模型,该模型采用基于可信网络连接的网络接入控制机制,并在该机制中采用群笛卡尔积加密算法的密钥机制来实现vTPM的完整性验证模块。经过安全性分析证明该模型能够提高云服务商对用户接入的可信度。     

可信计算平台及其研究现状

可信计算平台是信息安全技术研究的一个热点。本文详细介绍了可信计算平台的组成及其体系结构,描述了可信计算平台的特点和原理机制,并对目前可信计算平台的研究现状和存在的问题进行了总结。     

A trusted environment construction method for security-sensitive software

This paper presents a trusted-environment construction method based on the underlying hardware.This method aims at protecting the security-sensitive software in the aspects of software loading,running,and storing in the general operating system.It extends the trust chain of the traditional trusted computing technology to reach the target software,ensuring trusted loading.The extended memory management mechanism effectively prevents memory dumping and memory tampering for the high-sensitivity data.The file monitoring mechanism protects files from vicious operation made by attackers.Flexible-expanded storage environment provides the target software with static storing protection.Experimental system verifies that the method is suitable for general operating system and can effectively protect security-sensitive software with low overhead.     

MANET信任路由机制的研究

MANET网络的路由行为表现为若干移动节点间的动态协作,由于无法解决节点的恶意行为问题的传统路由协议不能有效解决传输路径的可靠发现与选择,在对节点路由行为逻辑进行分析的基础上,建立节点的转发概率模型,将节点转发行为转化为对节点路由的信任度量与动态评估问题,以实现端到端路由信任量化与预测。仿真实验结果表明,所提出的信任路由选择算法,可以有效地刻画传输路径的信任特性,实现信任路由选择策略。     

Trustworthiness Technologies of DDSS

The most significant strategic development in information technology over the past years has been ＂trusted computing＂ and trusted computers have been produced. In this paper trusted mechanisms adopted by PC is imported into distributed system, such as chain of trust, trusted root and so on. Based on distributed database server system （DDSS）, a novel model of trusted distributed database server system （TDDSS） is presented ultimately. In TDDSS role-based access control, two-level of logs and other technologies are adopted to ensure the trustworthiness of the system.     

Architecture of Trusted PC

This paper, focusing on the trusted computing group＇s standards, explained the key concept of trusted compuling and provided the architecture of trusted PC. It built trust bottom-up by starting with trusted hardware and adding layers of trusted software. It is a system-level solution available to all applications running on the member platforms. This solution reduces the security burden on applications and thus simplifies application programming.     

Cloud Virtual Machine Lifecycle Security Framework Based on Trusted Computing

As a foundation component of cloud computing platforms, Virtual Machines(VMs) are confronted with numerous security threats. However, existing solutions tend to focus on solving threats in a specific state of the VM. In this paper, we propose a novel VM lifecycle security protection framework based on trusted computing to solve the security threats to VMs throughout their entire lifecycle. Specifically, a concept of the VM lifecycle is presented divided up by the different active conditions of the VM. Then, a trusted computing based security protection framework is developed, which can extend the trusted relationship from trusted platform module to the VM and protect the security and reliability of the VM throughout its lifecycle. The theoretical analysis shows that our proposed framework can provide comprehensive safety to VM in all of its states. Furthermore, experiment results demonstrate that the proposed framework is feasible and achieves a higher level of security compared with some state-of-the-art schemes.     

Recent advances on trusted computing in China

This article highlights some recent research advances on trusted computing in China,focusing mainly on the methodologies and technologies related to trusted computing module,trusted computing platform,trusted network connection,trusted storage,and trustworthy software.