Challenges for Trusted Computing

This article identifies and discusses some of the key challenges that need to be addressed if the vision of Trusted Computing is to become reality. Topics addressed include issues with setting up and maintaining the PKI required to support the full set of Trusted Computing functionality, the practical use and verification of attestation evidence, and backwards compatibility, usability and compliance issues

Application of trusted computing to secure video broadcasts to mobile receivers

This paper addresses the problem of configuring mobile devices to receive broadcast services protected by legacy conditional access systems. The protocols apply the concepts of trusted computing to allow a mobile host to demonstrate that it is secure, before any application or associated keys are securely downloaded. Thus the protocols are applicable anywhere a secure download is required. A general analysis of the security of the protocols is presented, followed by the results of formal verification.

Authorisation Issues for Mobile Code in Mobile Systems

This thesis is concerned with authorisation issues for mobile code in mobile systems. It is divided into three main parts. Part I covers the development of a policy-based framework for the authorisation of mobile code and agents by host systems. Part II addresses the secure download, storage and execution of a conditional access application, used in the secure distribution of digital video broadcast content. Part III explores the way in which trusted computing technology may be used in the robust implementation of OMA DRM version 2. In part I of this thesis, we construct a policy-based mobile code and agent authorisation framework, with the objective of providing both mobile devices and service providers with the ability to assign appropriate privileges to incoming executables. Whilst mobile code and agent authorisation mechanisms have previously been considered in a general context, this thesis focuses on the special requirements resulting from mobile code and agent authorisation in a mobile environment, which restrict the types of solutions that may be viable. Following the description and analysis of a number of architectural models upon which a policy-based framework for mobile code and agent authorisation may be constructed, we outline a list of features desirable in the definitive underlying architecture. Specific implementation requirements for the capabilities of the policy and attribute certificate specification languages and the associated policy engine are then extracted. Candidate policy specification languages, namely KeyNote (and Nereus), Ponder (and (D)TPL) and SAML are then examined, and conclusions drawn regarding their suitability for framework expression. Finally, the definitive policy based framework for mobile code and agent authorisation is described. In the second part of this thesis, a flexible approach that allows consumer products to support a wide range of proprietary content protection systems, or more specifically digital video broadcast conditional access systems, is proposed. Two protocols for the secure download of content protection software to mobile devices are described. The protocols apply concepts from trusted computing to demonstrate that a platform is in a sufficiently trustworthy state before any application or associated keys are securely downloaded. The protocols are designed to allow mobile devices to receive broadcast content protected by proprietary conditional access applications. Generic protocols are first described, followed by an analysis of how well the downloaded code is protected in transmission. How the generic protocols may be implemented using specific trusted computing technologies is then investigated. For each of the selected trusted computing technologies, an analysis of how the conditional access application is protected while in storage and while executing on the mobile host is also presented. We then examine two previously proposed download protocols, which assume a mobile receiver compliant with the XOM and AEGIS system architectures. Both protocols are then analysed against the security requirements defined for secure application download, storage and execution. We subsequently give a series of proposed enhancements to the protocols which are designed to address the identified shortcomings. In the final section of this thesis, we examine OMA DRM version 2, which defines the messages, protocols and mechanisms necessary in order to control the use of digital content in a mobile environment. However, an organisation, such as the CMLA, must specify how robust implementations of the OMA DRM version 2 specification should be, so that content providers can be confident that their content will be safe on OMA DRM version 2 devices. We take the requirements extracted for the robust implementation of the OMA DRM version 2 specification and propose an implementation which meets these requirements using the TCG architecture and TPM/TSS version 1.2 commands

Trusted Computing: Security and Applications

The main objective of this paper is to highlight some of the major security and application issues confronting trusted computing technology. This technology, now present in a large proportion of new PCs and incorporating a wide range of cryptographic functionality, has the potential to have a major practical impact, but has not been widely discussed. This paper is an attempt to encourage greater debate about this technology and its possible implications. Following a brief introduction to the history of trusted computing, we provide a summary of its main features. This leads naturally to a consideration of the issues which may impede its use, including potential problems with its cryptographic components. Possible applications of the technology are then discussed. 1 Keywords: trusted computing, computer security, trust