A User Centric Security Model for Tamper-Resistant Devices

3.5 Security and Operational Requirements of the UCOM
3.4.6.3 Application Services Authentication Server (ASAS)
An ASAS authenticates the valid lease of an application that the requesting card holds. In
the UCOM, multiple smart cards of a single user may have an SP's application, depending
on the particular SP's ALP. If the ALP allows multiple smart cards to have a valid lease
of its applications, an ASAS is necessary to verify the validity of the lease to the smart
card. Once a smart card is authenticated as holding the valid leased application, it can
access services oered by the SP, subject to successful authentication by the user (user's
application).
The ASAS is already implemented in the ICOM, and is referred as a back-oce or transaction
clearance system. Each industry has its unique way of implementing the ASAS and
part of the design philosophy of the UCOM is that we do not require a modication (in
most cases) to the existing architecture of the ASAS in the ICOM.
3.4.7 Service Access Point (SAP)
Any device that a cardholder can use to access services provided by an SP is called a
Service Access Point (SAP). A SAP can be a mobile phone, a kiosk, a computer, or an
access panel. The main function of all these devices is to connect with the SP through a
smart card and provide services to the cardholder. We consider that SAPs do not have
to be secure; therefore, during the course of this thesis SAPs will be treated as insecure
terminals.
3.5 Security and Operational Requirements of the UCOM
The UCOM delegates control of the smart card to its user. This scenario introduces unique
requirements that were not present in the ICOM.
3.5.1 General Requirements
In this section, we discuss the requirements that are not specic to a particular entity in
the UCOM but are instead common to the overall architecture.
GR1. Control: The UCOM should provide a mechanism(s) that enables cardholders to
manage applications on their smart cards. It should also ensure that only the autho-
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