IEEE Access Special Section Editorial: Trusted Computing

As the platform mobility increases, it becomes increasingly susceptible to theft. Stolen data is often regarded as being more valuable than the notebook hardware itself. Thus, the need to protect user data and secrets is underscored in a mobile computing environment. The Trusted Platform Module (TPM) is defined as a hardware instantiation which has been proposed by the TCG (Trusted Computing Group) for trust computing. TPM offers facilities for the secure generation of cryptographic keys, and limitations on their use, in addition to a hardware pseudo-random number generator. It also includes capabilities such as remote attestation and sealed storage. A TPM can be used to authenticate hardware devices. Since each TPM chip has a unique and secret RSA key burned in during production, it is capable of performing platform authentication. The TPB (Trusted Platform Board) is an expansion of the TPM for enhancing the efficiency and usability of the TPM chip. In addition to the TPB functions supporting high-standard trust environments within the hardware standard of the system in this paper, we develop the v-TMS (Visual Trustworthy Monitoring System) that provides visualization of real-time monitoring for the behavior of system resources (process, memory, network, users, etc.) with TPB and system software for hardening of OS and applications. Moreover, v-TMS is not only a web-based computing environment for system resources but also a real-time monitoring system for a trust computing environment.

Trusted computing (TC) is considered to be one of the newly developed technologies on improving computer security and creating a trustworthy environment. Although the Trusted Computing Group (TCG) has defined specifications/or TC, including that of trusted platform module (TPM), criteria on compliance testing is still not available. It is important that the design and implementation of TPM and other components follow the specifications, as incompliance may lead to crucial security impacts. In this paper, a test mechanism checking TPM commands is instrumented into TPM application, so that conformance to standards can be examined before TPM's functional execution to validate its compliance with the specifications. Furthermore, this paper also initially puts forward the concept of "chain of compliance", which enhances the trustworthiness of computing platforms by verifying the conformance of their components.

Computation outsourcing has become a hot topic in both academic research and industry. This is because of the benefits accompanied with outsourcing, such as cost reduction, focusing on core businesses and possibility for benefiting from modern payment models like the pay-per-use model. Unfortunately, outsourcing to potentially untrusted third parties' hosting platforms requires a lot of trust. Clients need assurance that the intended code was loaded and executed, and that the application behaves correctly and trustworthy at runtime. That is, techniques from Trusted Computing which are used to allow issuing evidence about the execution of binaries and reporting it to a challenger are not sufficient. Challengers are more interested in evidence which allows detecting misbehavior while the outsourced computation is running on the hosting platform. Another challenging issue is providing a secure data storage for collected evidence information. Such a secure data storage is provided by the Trusted Platform Module (TPM). In outsourcing scenarios where virtualizations technologies are applied, the use of virtual TPMs (vTPMs) comes into consideration. However, researcher identified some drawbacks and limitations of the use of TPMs. These problems include privacy and maintainability issues, problems with the sealing functionality and the high communication and management efforts. On the other hand, virtualizing TPMs, especially virutalizing the Platform Configuration Registers (PCRs), strikes against one of the core principles of Trusted Computing, namely the need for a hardware-based secure storage. In this thesis, we propose different approaches and architectures which can be used to mitigate the problems above. In particular, in the first part of our thesis we propose an approach called Behavior Compliance Control (BCC) to defines architectures to describe how the behavior of such outsourced computations is captured and controlled as well as how to judge the compliance of it compared to a trusted behavior model. We present approaches for two abstraction levels; one on a program code level and the other is on the level of abstract executable business processes. In the second part of this thesis, we propose approaches to solve the aforementioned problems related to TPMs and vTPMs, which are used as storage for evidence data collected as assurance for behavior compliance. In particular, we recognized that the use of the SHA-1 hash to measure system components requires maintenance of a large set of hashes of presumably trustworthy software; furthermore, during attestation, the full configuration of the platform is revealed. Thus, our approach shows how the use of chameleon hashes allows to mitigate the impact of these two problems. To increase the security of vTPM, we show in another approach how strength of hardware-based security can be gained in virtual PCRs by binding them to their corresponding hardware PCRs. We propose two approaches for such a binding. For this purpose, the first variant uses binary hash trees, whereas the other variant uses incremental hashing. We further provide implementations of the proposed approach and evaluate their impact in practice. Furthermore, we empirically evaluate the relative efficacy of the different behavioral abstractions of BCC that we define based on different real world applications. In particular, we examined the feasibility, the effectiveness, the scalability and efficiency of the approach. To this end, we chose two kinds of applications, a web-based and a desktop application, performing different attacks on them, such as malicious input attach and SQL injection attack. The results show that such attacks can be detected so that the application of our approach can increase the protection against them.

Cloud computing platforms constructed on Trusted Computing Technology are commonly referred to as trusted cloud computing. The core component of this technology is known as Trusted Platform Module (TPM). Its specifications are given by the consortium known as Trusted Computing Group (TCG). Though TPM is an immovable module and is fixed inside any computer, yet its credentials can be shared with other devices. This paper presents the accessibility model for Virtual Machine (VM) of a distributed trust protocol which is based on TPM, through which consumer's credentials are shared to other trusted devices. These credentials essentially describe the integrity of VM.

Trusted Platform Module (TPM) is a key component designed to enable computers achieve greater security. Several vulnerabilities discovered in the TPM highlight the necessity of formal analysis. The procedure invoking an API may be regarded as several interactive processes between the TPM and a user. As a result, the current study formalized the API specifications proposed by Trusted Computing Group (TCG) using applied pi calculus. Meanwhile, two authentication properties between them were also described in a formalized way. With the help of the tool ProVerif, the flaw of the command TPM_CertifyKey was discovered. It was also confirmed on the TPM emulator. Subsequently, the modified API was presented and its authentication properties could be satisfied after verifying again. Results show the model is valid. DOI: http://dx.doi.org/10.11591/telkomnika.v11i2.2034

3 - Overview of the TPM Architecture

<p>A computer hijacked by a malware may pretend that it is normal as usual and retrieve secrets from storage of itself and other victim computers. By adopting trusted computing technology a computer’s former health status cannot be forged. Computers can thus detect the change of health status of a hijacked computer and prevent the leakage of the secrets. As Trusted Computing Group (TCG) proposed Trusted Platform Module (TPM) specification, IBM implemented software TPM (sTPM) and utilities for engineer who wants to learn the operating principle of TPM. Meanwhile, the blooming of tiny size, but powerful, computers, e.g. Raspberry Pi 2 (Rpi2), attract ones to develop some dedicated applications on the computers. In this article, we report the verified steps for installing new sTPM version on RPi2. After the installation, we also test the functionality and evaluate the performance of the sTPM with some major TPM Commands. The real behaviour of and the traffic between the host computer and the emulated TPM can thus be learned easily.</p>

This paper describes the direct anonymous attestation scheme (DAA). This scheme was adopted by the Trusted Computing Group (TCG) as the method for remote authentication of a hardware module, called Trusted Platform Module (TPM), while preserving the privacy of the user of the platform that contains the module. DAA can be seen as a group signature without the feature that a signature can be opened, i.e., the anonymity is not revocable. Moreover, DAA allows for pseudonyms, i.e., for each signature a user (in agreement with the recipient of the signature) can decide whether or not the signature should be linkable to another signature. DAA furthermore allows for detection of known keys: if the DAA secret keys are extracted from a TPM and published, a verifier can detect that a signature was produced using these secret keys. The scheme is provably secure in the random oracle model under the strong RSA and the decisional Diffie-Hellman assumption.

: The design of a trusted system based on the Trusted Computing Group's Trusted Platform Module (TPM) was analyzed to understand the role and trust relationships of the TPM, firmware, and software modules involved. The objective was to confirm that the measurements stored and reported by the TPM can successfully discriminate a normal boot sequence, which leaves trusted system software in control, from an insecure one, where some trusted modules might have been replaced by malicious ones. The principal tool used in the analysis was the SMV symbolic model checker.

To prevent unauthorized access to protected trusted platform module (TPM) objects, authorization protocols, such as the object-specific authorization protocol (OSAP), have been introduced by the trusted computing group (TCG). By using OSAP, processes trying to gain access to the protected TPM objects need to prove their knowledge of relevant authorization data before access to the objects can be granted. Chen and Ryan's 2009 analysis has demonstrated OSAP's authentication vulnerability in sessions with shared authorization data. They also proposed the Session Key Authorization Protocol (SKAP) with fewer stages as an alternative to OSAP. Chen and Ryan's analysis of SKAP using ProVerif proves the authentication property. The purpose of this paper was to examine the usefulness of Colored Petri Nets (CPN) and CPN Tools for security analysis. Using OSAP and SKAP as case studies, we construct intruder and authentication property models in CPN. CPN Tools is used to verify the authentication property using a Dolev---Yao-based model. Verification of the authentication property in both models using the state space tool produces results consistent with those of Chen and Ryan.

Verifiable trust is a desirable property for computing platforms. Current trusted computing systems developed by Trusted Computing Group (TCG) provide verifiable trust by taking immutable snapshots of the whole set of platform components. It is, however, difficult to use this technology directly in virtualized platforms because of complexity and dynamic changes of platform components. In this paper, we introduce a novel integrity management solution based on a small Software-based Root of Trust for Measurement (SRTM) that provides a trusted link to the integrity measurement chain in the TCG technology.Our solution makes two principal contributions: The first is a key management method, by which a verifier can be convinced that the SRTM is a trusted delegatee of a Trusted Platform Module (TPM). The second is two integrity management services, which provides a novel dependency relation between platform components and enables reversible changes to measured components. This extended abstract of the paper focuses on the key management method and shows the high level idea of these two services. Details of the dependency relation, the reversible changes, and the Xen implementation may be found in the full version of the paper.KeywordsIntegrity measurement and reportingplatform virtualizationsoftware-based root of trust for measurement

Remote Attestation (RA) enables the integrity and authenticity of applications in Trusted Execution Environment (TEE) to be verified. Existing TEE RA designs employ a centralized trust model where they rely on a single provisioned secret key and a centralized verifier to establish trust for remote parties. This model is however brittle and can be untrusted under advanced attacks nowadays. Besides, most designs only have fixed procedures once deployed, making them hard to adapt to different emerging situations and provide resilient functionalities. Therefore, we propose <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Janus</small>, an open and resilient TEE RA scheme. To decentralize trust, we, on one hand, introduce Physically Unclonable Function (PUF) as an intrinsic root of trust (RoT) in TEE to directly provide physical trusted measurements. On the other hand, we design novel decentralized verification functions on smart contract with result audits and RA session snapshot. Furthermore, we design an automated switch mechanism that allows <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Janus</small> to remain resilient and offer flexible RA services under various situations. We provide a UC-based security proof and demonstrate the scalability and generality of <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Janus</small> by implementing an complete prototype.

In the traditional client-server architecture, the server is the focus of security, but the huge numbers of terminals have the relatively small consideration. Through the practice of the information security, people have realized that the security problem mainly comes from network terminals. To ensure the source security of network terminals, the solution must be brainstormed synthetically from the chips, hardware architectures, operating systems, etc., which comes into being the original idea of the Trusted Computing (TC). TC binds a trusted platform modular (TPM) to the terminal to ensure the security of the client, by which a trusted chain is established to protect the whole system and network. In this section, we introduce the TC technology, TC framework, trusted platform module, and trusted mobile platform. Especially, we research the TC based client security architecture, and indicate that the key point is the security operating system which can support TC. Finally, a comparison among the secure kernel based, micro kernel based, and virtual machine based terminal architectures is proposed.

The Trusted Computing Group (TCG) has proposed the binary attestation mechanism that enables a computing platform with a dedicated security chip, the Trusted Platform Module (TPM), to report its state to remote parties. The concept of property-based attestation (PBA) improves the binary attestation and compensates for some of its main deficiencies. In particular, PBA enhances user privacy by allowing the trusted platform to prove to a remote entity that it has certain properties without revealing its own configuration.The existing PBA solutions, however, require a Trusted Third Party (TTP) to provide a reliable link of configurations to properties, e.g., by means of certificates. We present a new privacy-preserving PBA approach that avoids such a TTP. We define a formal model, propose an efficient protocol based on the ideas of ring signatures, and prove its security. The cryptographic technique deployed in our protocol is of independent interest, as it shows how ring signatures can be used to efficiently prove the knowledge of an element in a list without disclosing it.

An Advanced Trusted Platform for mobile phone devices