A User Centric Security Model for Tamper-Resistant Devices

10.1 Summary and Conclusions
giving the user authentication credentials for these SPs. We discuss the card management
architectures proposed by GlobalPlatform, and Multos. The rationale behind not
discussing the Java Card was to do with its support for the GlobalPlatform. We briey described
the shortfalls of both GlobalPlatform and Multos card management architectures.
Subsequently, we modied the architecture specied by GlobalPlatform in a way that supported
the application installation mechanism of the UCOM. Later, we also proposed the
possible attacks that are unique to the UCOM proposal along with how a smart card can
adequately implement protection against them.
Based on the card management architecture, we proceeded with the application installation
process. The installation process rst requires a secure channel to be established between
a smart card and an SP. It also requires that an SP is able to ascertain the trustworthiness
of the smart card to enable the SP to verify whether the given smart card supports the
SP's security policy for the application lease. For this purpose, we dened the security and
operational requirements for a Secure and Trusted Channel Protocol (STCP) for UCOMbased
smart cards. We proposed three protocols that satisfy the UCOM requirements and
these protocols were subjected to the CasperFDR tool for a mechanical formal analysis. We
performed the mechanical formal analysis on the STCPs for the sake of completeness. In
addition to this, we provided performance results of test implementations and compared
them with existing protocols. Our proposed STCPs not only satised the security and
operational requirements of the UCOM but also provided an ecient performance. After
establishing a secure and trusted channel protocol, an SP may proceed with the application
download to the requesting smart card.
A downloaded application on a smart card may establish data and resource sharing with
other applications. Both Java Card and Multos support the application sharing mechanism;
however, their proposals take two opposite approaches. We discussed both approaches and
detailed the reasons why they fail the UCOM's requirements. Subsequently, we proposed a
smart card rewall mechanism based on the Java Card application sharing mechanism that
supports the UCOM's requirements. To support this proposal, a dynamic mechanism is
needed that not only authenticates the applications but also ascertains whether the current
states of the applications are secure. For this purpose, we proposed a symmetric key-based
protocol that a client and server application can use to authenticate and validate each
other's state. Later, we extended the application sharing mechanism that traditionally
only supports sharing between the applications on a single smart card, to one that allows
applications installed on dierent smart cards to share their data and resources. We
termed this extension as Cross-Device Application Sharing and to support this proposal
we detailed two protocols that establish relationships between individual smart cards and
applications. All proposed protocols were subjected to mechanical formal analysis by
CasperFDR and their test performance measures were provided along with comparisons
with other protocols. Once an application is installed and it has established any sharing
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