Modeling Trusted Computing

In this paper, a formal approach based on predicate logic is proposed for representing and reasoning of trusted computing models. Predicates are defined to represent the characteristics of the objects and the relationship among these objects in a trusted system according to trusted computing specifications. Inference rules of trusted relation are given too. With the semantics proposed, some trusted computing models are formalized and verified, which shows that Predicate calculus logic provides a general and effective method for modeling and reasoning trusted computing systems.

Security Architecture of Trusted Virtual Machine Monitor for Trusted Computing

With analysis of limitations Trusted Computing Group （TCG） has encountered, we argued that virtual machine monitor （VMM） is the appropriate architecture for implementing TCG specification. Putting together the VMM architecture, TCG hardware and application-oriented ＂thin＂ virtual machine （VM）, Trusted VMM-based security architecture is present in this paper with the character of reduced and distributed trusted computing base （TCB）. It provides isolation and integrity guarantees based on which general security requirements can be satisfied.

Protecting Terminals by Security Domain Mechanism Based on Trusted Computing

Networks are composed with servers and rather larger amounts of terminals and most menace of attack and virus come from terminals. Eliminating malicious code and ac cess or breaking the conditions only under witch attack or virus can be invoked in those terminals would be the most effec tive way to protect information systems. The concept of trusted computing was first introduced into terminal virus immunity. Then a model of security domain mechanism based on trusted computing to protect computers from proposed from abstracting the general information systems. The principle of attack resistant and venture limitation of the model was demonstrated by means of mathematical analysis, and the realization of the model was proposed.

Development of Trusted Computing Research

Trusted computing is the new trend of information security today. This paper surveys the theory and technology of trusted computing. The development history of trusted computing, and the development of trusted computing in China are introduced in this paper, and then it analyzes some problems of trusted computing at present which are delay in theory research, some key technologies to be developed and lack of trusted software system. Some fields are worthy to be explored on are pointed out including key technology, basic theory and application in trusted computing.

An Improved Grid Security Infrastructure by Trusted Computing

Current delegation mechanism of grid security infrastructure （GSI） can＇t satisfy the requirement of dynamic, distributed and practical security in grid virtual organization. To improve this situation, a TC-enabled GSI is discussed in this paper. With TC-enabled GSI, a practical delegation solution is proposed in this paper through enforcing fine granularity policy over distributed platforms with the emerging trusted computing technologies. Here trusted platform module is treated as a tamper-resistance module to improve grid security infrastructure. With the implement of Project Daonity, it is demonstrated that the solution could gain dynamic and distributed security in grid environment.

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.

A Peer-to-Peer Resource Sharing Scheme Using Trusted Computing Technology

Facing the increasing security issues in P2P networks, a scheme for resource sharing using trusted computing technologies is proposed in this paper. We advance a RS-UCON model with decision continuity and attribute mutability to control the usage process and an architecture to illustrate how TC technologies support policy enforcement with bidirectional attestation. The properties required for attestation should include not only integrity measurement value of platform and related application, but also reputation of users and access history, in order to avoid the limitation of the existing approaches. To make a permission, it is required to evaluate both the authorization and conditions of the subject and the object in resource usage to ensure trustable resources to be transferred to trusted users and platform.

A Security Kernel Architecture Based Trusted Computing Platform

A security kernel architeclrne built on trusted computing platform in thelight of thinking about trusted computing is presented According to this architecture, a newsecurity module TCB (Trusted Computing Base) is added to the operation system kerneland twooperation interface modes are provided for the sake of self-protection. The security kernel isdivided into two parts and trusted mechanism Is separated from security functionality. Ihe TCBmodule implements the trusted mechanism such as measurement and attestation, while the othercomponents of security kernel provide security functionality based on these mechanisms. Thisarchitecture takes full advantage of functions provided by trusted platform and clearly defines thesecurity perimeter of TCB so as to assure stlf-securily from architcetmal vision. We also presentfunction description of TCB and discuss the strengths and limitations comparing with other relatedresearches.

The Mechanism about Key and Credential on Trusted Computing Platform and the Application Study

Trusted Computing technology is quickly developing in recent years. This technology manages to improve the computer security and archive a trusted computing environment. The core of trusted computing technology is cryptology. In this paper, we analyze the key and credential mechanism which is two basic aspects in the cryptology application of trusted computing. We give an example application to illustrate that the TPM enabled key and credential mechanism can improve the security of computer system.

Merkle Tree Digital Signature and Trusted Computing Platform

Lack of efficiency in the initial key generation process is a serious shortcoming of Merkle tree signature scheme with a large number of possible signatures. Based on two kinds of Merkle trees, a new tree type signature scheme is constructed, and it is provably existentially unforgeable under adaptive chosen message attack. By decentralizing the initial key generation process of the original scheme within the signature process, a large Merkle tree with 6.87×10^10 possible signatures can be initialized in 590 milliseconds. Storing some small Merkle trees in hard disk and memory can speed up Merkle tree signature scheme. Mekle tree signature schemes are fit for trusted computing platform in most scenarios.

Efficient and Secure Multi-Signature Scheme Based on Trusted Computing

A new multi-signature scheme was proposed with the extension of the direct anonymous attestation （DAA） protocol supported by trusted computing （TC） technology. Analysis and simulation results show that the signer＇s privacy is well protected with dynamic anonymity, the public key and signatures have length independent of the number of signature members, new signers are allowed to join the signature without modifying the public key, and attacks caused by secret key dumping or leaking can be avoided.

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 portable TPM scheme for general-purpose trusted computing based on EFI

In today＇s globalized digital world, networkbased, mobile, and interactive collaborations have enabled work platforms of personal computers to cross multiple geographical boundaries. The new requirements of privacy-preservation, sensitive information sharing, portability, remote attestation, and robust security create new problems in system design and implementation. There are critical demands for highly secure work platforms and security enhancing mechanisms for ensuring privacy protection, component integrity, sealed storage, and remote attestation of platforms. Trusted computing is a promising technology for enhancing the security of a platform using a trusted platform module （TPM）. TPM is a tamper-resistant microcontroller designed to provide robust security capabilities for computing platforms. It typically is affixed to the motherboard with a low pin count （LPC） bus. However, it limited in that TPM cannot be used directly in current common personal computers （PCs）, and TPM is not flexible and portable enough to be used in different platforms because of its interface with the PC and its certificate and key structure. For these reasons, we propose a portable trusted platform module （PTPM） scheme to build a trusted platform for the common PC based on a single cryptographic chip with a universal serial bus （USB） interface and extensible firmware interface （EFI）, by which platforms can get a similar degree of security protection in general-purpose systems. We show the structure of certificates and keys, which can bind to platforms via a PTPM and provide users with portability and flexibility in different platforms while still allowing the user and platform to be protected and attested. The implementation of prototype system is described in detail and the performance of the PTPM on cryptographic operations and time-costs of the system bootstrap are evaluated and analyzed. The results of experiments show that PTPM has high performances for supporting trusted computing and it can be used flexibly and portably by the user.

A Trusted Mobile Payment Environment Based on Trusted Computing and Virtualization Technology

In this paper, we propose a trusted mobile payment environment （TMPE） based on trusted computing and virtualization technology. There are a normal operating system （OS） and a trusted OS （TOS） in TMPE. We store the image of TOS in a memory card to hinder tampering. The integrity of TOS is protected by means of a trusted platform module （TPM）. TOS can only be updated through a trusted third party. In addition, virtualization technology is applied to isolate TOS from normal OS. Users complete ordinary affairs in normal OS and security-sensitive affairs in TOS. TMPE can offer users a highly protected environment for mobile payment. Moreover, TMPE has good compatibility in different hardware architectures of mobile platforms. As the evaluation shows, TMPE satisfies the requirement of mobile payment well.

Formal Compatibility Model for Trusted Computing Applications

The Chinese specification for trusted computing, which has similar functions with those defined by the Trusted Computing Group （TCG）, has adopted a different cryptography scheme. Applications designed for the TCG specifications cannot directly function on platforms complying with Chinese specifications because the two cryptography schemes are not compatible with each other. In order to transplant those applications with little to no modification, the paper presents a formal compatibility model based on Zaremski and Wing＇s type system. Our model is concerned not only on the syntactic compatibility for data type, but also on the semantic compatibility for cryptographic attributes according to the feature of trusted computing. A compatibility algorithm is proposed based on the model to generate adapters for trusted computing applications.

A Star-Style Trust Model with the Ability of Data Recovery for Trusted Computing Platform

Varieties of trusted computing products usually follow the mechanism of liner-style chain of trust according to the specifications of TCG.The distinct advantage is that the compatibility with the existing computing platform is preferable,while the shortcomings are obvious simultaneously.A new star-style trust model with the ability of data recovery is proposed in this paper.The model can enhance the hardware-based root of trust in platform measurement,reduce the loss of trust during transfer process,extend the border of trust flexibly,and have the ability of data backup and recovery.The security and reliability of system is much more improved.It is proved that the star-style trust model is much better than the liner-style trust model in trust transfer and boundary extending etc.using formal methods in this paper.We illuminate the design and implementation of a kind of trusted PDA acting on star-style trust model.

Static Analysis-Based Behavior Model Building for Trusted Computing Dynamic Verification

Current trusted computing platform only verifies application＇s static Hash value, it could not prevent application from being dynamic attacked. This paper gives one static analysis-based behavior model building method for trusted computing dynamic verification, including control flow graph （CFG） building, finite state automata （FSA） constructing, e run cycle removing, e transition removing, deterministic finite state （DFA） constructing, trivial FSA removing, and global push down automata （PDA） constructing. According to experiment, this model built is a reduced model for dynamic verification and covers all possible paths, because it is based on binary file static analysis.

Remote Attestation-Based Access Control on Trusted Computing Platform

Existing remote attestation schemes based on trusted computing have some merits on enhancing security assurance level, but they usually do not integrate tightly with the classical system security mechanism. In this paper, we present a component named remote attestation-based access controller （RABAC）, which is based on a combination of techniques, such as random number, Bell-La Padula （BLP） model, user identity combined with his security properties and so on. The component can validate the current hardware and software integrity of the remote platform, and implement access control with different security policy. We prove that the RABAC can not only improve the security of transferred information in remote attestation process but also integrate remote attestation and classical system security mechanism effectively.

Quorum systems for intrusion-tolerance based on trusted timely computing base

Quorum systems have been used to solve the problem of data consistency in distributed fault-tolerance systems. But when intrusions occur, traditional quorum systems have some disadvantages. For example, synchronous quorum systems are subject to DOS attacks, while asynchronous quorum systems need a larger system size （at least 3f＋1 for generic data, and f fewer for self-verifying data）. In order to solve the problems above, an intrusion-tolerance quorum system （ITQS） of hybrid time model based on trust timely computing base is presented （TTCB）. The TTCB is a trust secure real-time component inside the server with a well defined interface and separated from the operation system. It is in the synchronous communication environment while the application layer in the server deals with read-write requests and executes update-copy protocols asynchronously. The architectural hybridization of synchrony and asynchrony can achieve the data consistency and availability correctly. We also build two kinds of ITQSes based on TTCB, i.e., the symmetrical and the asymmetrical TTCB quorum systems. In the performance evaluations, we show that TTCB quorum systems are of smaller size, lower load and higher availability.

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.