Ronald Toegl

A PrivacyCA for Anonymity and Trust

Trusted Computing (TC) as envisioned by the Trusted Computing Group promises a solution to the problem of establishing a trust relationship between otherwise unrelated platforms. In order to achieve this goal the platform has to be equipped with a Trusted Platform Module (TPM), which is true for millions of contemporary personal computers. The TPM provides solutions for measuring the state of a platform and reporting it in an authentic way to another entity. The same cryptographic means that ensure the authenticity also allow unique identification of the platform and therefore pose a privacy problem. To circumvent this problem the TCG proposed a trusted third party, the Privacy Certification Authority (PrivacyCA). Unfortunately, currently no PrivacyCA is generally available. In this paper we introduce our freely available implementation of a PrivacyCA. In addition, our PrivacyCA is itself a trusted service. It is capable of reporting its state to clients. Furthermore, we use a novel way to minimize the Trusted Computing Base of Java-based applications in conjunction with hardware-supported virtualization. We automatically generate the service interface from a structural specification. Thus, to the best of our knowledge, we were not only first to make this crucial service publicly available, but now also provide a trustworthy service whose privacy policy can be attested to its users by employing TC mechanisms.

Towards Trust Services for Language-Based Virtual Machines for Grid Computing

The concept of Trusted Computing (TC) promises a new approach to improve the security of computer systems. The core functionality, based on a hardware component known as Trusted Platform Module (TPM), is integrated into commonly available hardware. Still, only limited software support exists, especially in the context of grid computing. This paper discusses why platform independent virtual machines (VM) with their inherent security features are an ideal environment for trusted applications and services. Based on different TC architectures building a chain-of-trust, a VM can be executed in a secure way. This chain-of-trust can be extended at run-time by considering the identity of the application code and by deriving attestable properties from the VMs configuration. An interface to provide applications with TC services like sealing or remote attestation regardless of the underlying host architecture is discussed.

Tagging the Turtle: Local Attestation for Kiosk Computing

Public kiosk computers are especially exposed and the software running on them usually cannot be assumed to be unaltered and secure. The Trusted Platform Module (TPM) as a root of trust in an otherwise untrusted computer allows a machine to report the integrity and the configuration of a platform to a remote host on the Internet. A natural usage scenario is to perform such an Attestation prior to handling sensitive or private data on a public terminal. Two challenges arise. First, the human user needs to reach her trust decision on the basis of the TPMs cryptographic protocols. She cannot trust the public machine to display authentic results. Second, there is currently no way for the user to establish that the particular machine faced actually contains the TPM that performs the Attestation. In this paper we demonstrate an Attestation token architecture which is based on a commodity smart phone and more efficient and flexible than previous proposals. Further, we propose to add a low-cost Near Field Communication (NFC) compatible autonomic interface to the TPM, providing a direct channel for proof of the TPMs identity and local proximity to the Attestation token.

A practical approach for establishing trust relationships between remote platforms using trusted computing

Over the past years, many different approaches and concepts in order to increase computer security have been presented. One of the most promising of these concepts is Trusted Computing which offers various services and functionalities like reporting and verifying the integrity and the configuration of a platform (attestation). The idea of reporting a platforms state and configuration to a challenger opens new and innovative ways of establishing trust relationships between entities. However, common applications are not aware of Trusted Computing facilities and are therefore not able to utilise Trusted Computing services at the moment. Hence, this article proposes an architecture that enables arbitrary applications to perform remote platform attestation, allowing them to establish trust based on their current configuration. The architectures components discussed in this article are also essential parts of the OpenTC proof-of-concept prototype. It demonstrates applications and techniques of the Trusted Computing Groups proposed attestation mechanism in the area of personal electronic transactions.

A Trusted Platform Module for Near Field Communication

Near Field Communication (NFC) has become widely available on smart phones. It helps users to intuitively establish communication between local devices. Accessing devices such as public terminals raises several security concerns in terms of confidentiality and trust. To overcome this issue, NFC can be used to leverage the trusted-computing protocol of remote attestation. In this paper, we propose an NFC-enabled Trusted Platform Module (TPM) architecture that allows users to verify the security status of public terminals. For this, we introduce an autonomic and low-cost NFC-compatible interface to the TPM to create a direct trusted channel. Users can access the TPM with NFC-enabled devices. The architecture is based on elliptic-curve cryptography and provides efficient signing and verifying of the security-status report. As a proof-of-concept, we implemented an NFC-enabled TPM platform and show that a trust decision can be realized with commodity smart phones. The NFC-enabled TPM can effectively help to overcome confidentiality issues in common public-terminal applications.

acTvSM: a dynamic virtualization platform for enforcement of application integrity

Modern PC platforms offer hardware-based virtualization and advanced Trusted Computing mechanisms. Hardware primitives allow the measuring and reporting of software configurations, the separation of application execution environments into isolated partitions and the dynamic switch into a trusted CPU mode. In this paper we present a practical system architecture which leverages hardware mechanisms found in mass-market off-the-shelf PCs to improve the security of commodity guest operating systems by enforcing the integrity of application images. We enable the platform administrator to freely and deterministically specify the configurations trusted. Furthermore, we describe a set of tools and operational procedures to allow flexible and dynamic configuration management and to guarantee the secure transition between trusted platform configurations. We present our prototype implementation which integrates well with established Linux distributions.

An autonomous attestation token to secure mobile agents in disaster response

Modern communication and computing devices have the potential to increase the efficiency of disaster response. Mobile agents are a decentralized and flexible technology to leverage this potential. While mobile agent platforms suffer from a greater variety of security risks than the classic client-server approach, Trusted Computing is capable of alleviating these problems. Unfortunately, Remote Attestation, a core concept of Trusted Computing, requires a powerful networked entity to perform trust decisions. The existence and availability of such a service in a disaster response scenario cannot be relied upon. In this paper we introduce the Autonomous Attestation Token (AAT), a hardware token for mobile computing devices that is capable of guaranteeing the trusted state of a limited set of devices without relying on a networked service. We propose a Local Attestation protocol with user interaction that in conjunction with the AAT allows to prevent unauthorized access to an emergency mobile agent platform.

An approach to introducing locality in remote attestation using near field communications

Remote Attestation, as devised by the Trusted Computing Group, is based on a secure hardware component—the Trusted Platform Module (TPM). It allows to reach trust decisions between different network hosts. However, attestation cannot be applied in an important field of application—the identification of physically encountered, public computer platforms. Unfortunately, such computer terminals are especially exposed and the software running on them cannot be assumed unaltered and secure.Three challenges arise. The cryptographic protocols that actually perform the attestation do not provide for human-intelligible trust status analysis, easily graspable conveyance of results, nor the intuitive identification of the computer platform involved. Therefore, the user needs a small portable device, a token, to interact with local computer platforms. It can perform an attestation protocol, report the result to the user, even if the display the user faces cannot be trusted and may be connected to the platform under scrutiny. In addition, the token must establish that the particular machine faced actually contains the TPM that performs the attestation.In this paper, we demonstrate an attestation token architecture which is based on a commodity smart phone and which is more efficient and flexible than previous proposals. Furthermore, we introduce an autonomic and low-cost Near Field Communication (NFC) compatible interface to the TPM that provides a direct channel for proof of the TPM’s identity and local proximity to the attestation token.

An Autonomous Attestation Token to Secure Mobile Agents in Disaster Response

Modern communication and computing devices have the potential to increase the efficiency of disaster response. Mobile agents are a decentralized and flexible technology to leverage this potential. While mobile agent platforms suffer from a greater variety of security risks than the classic client-server approach, Trusted Computing is capable of alleviating these problems. Unfortunately, Remote Attestation, a core concept of Trusted Computing, requires a powerful networked entity to perform trust decisions. The existence and availability of such a service in a disaster response scenario cannot be relied upon.

Towards platform-independent trusted computing

Software independence from hardware platforms is an important feature of growing significance, given the emergence of new distributed computing paradigms. It would be desirable to extend the Trusted Computing mechanisms offered by the Trusted Platform Module into the platform independent Java environment. However, there is currently no generally accepted Trusted Computing API for Java. In this paper, we describe the design of a high-level API for Trusted Computing in Java, which is set to become the new industry standard for Java applications. We describe the current state of the standardization effort being undertaken in Java Specification Request 321 (JSR321).