Securing Mobile Ubiquitous Services using Trusted Computing

by Adrian Ho Yin Leung

RHUL-MA-2009-17

Abstract:

This thesis examines how trusted computing technology can be
used to enhance the security of ubiquitous services in mobile
environments.

It is envisaged that, in a mobile ubiquitous environment, users
(through one of their mobile devices and using a range of
network access technologies) will be able to seamlessly
discover, select, and access a rich offering of services and
content from a range of service providers. To realise this
vision, it is important that security and privacy issues are
addressed from the outset.

Initially we introduce the model of mobile ubiquitous computing
that underlies the discussions in the remainder of the thesis.
We then identify the security requirements for ubiquitous
service provision arising in the context of this model.

In Part II of the thesis we examine the technology of trusted
computing. We consider the effectiveness of a recently proposed
attack on one of the trusted computing primitives, namely the
Direct Anonymous Attestation protocol, and also examine ways in
which the attack can be prevented. We further cryptanalyse a
trusted computing based protocol designed to secure the storage
and distribution of secrets.

In the final part of the thesis, we propose three novel schemes
for mobile services security, all using trusted computing as
the primary building block. Firstly, we describe a Secure and
Private Service Discovery Protocol in which, during the service
discovery process, the trustworthiness of a user platform is
anonymously authenticated to a service provider, whilst a
service provider is simultaneously authenticated to the user.
The novel scheme possesses the following desirable properties:
user anonymity, service information confidentiality,
unlinkability, and rogue blacklisting.

We next present a Device Management Framework for Secure
Service Delivery. Apart from providing secure service
interactions between the service provider and user devices, the
framework is designed to reduce the complexity of device
security management tasks for users. The framework also
protects the interests of service providers by preventing
unauthorised credential sharing amongst user devices. One other
novel feature of the framework is that compromised devices are
self-revoking, hence removing the need for a cumbersome
revocation infrastructure.

Finally, we construct a Privacy-Preserving Content Watermarking
Scheme. Our scheme minimises the reliance on a TTP for privacy
protection, as the buyer can generate verifiable pseudonyms on
its own. As a result, we are able to reduce communication
overheads, and hence improve the overall efficiency compared to
existing schemes. In addition, the content provider is able to
obtain assurance that a buyer-generated watermark is
well-formed. The scheme also provides the following security
features: framing resistance, user anonymity, content
information confidentiality, unlinkability (even against the
TTP), and transaction linkability.