  To date, most work regarding the formal analysis of access control schemes
has focused on quantifying and comparing the expressive power of a set of
schemes. Although expressive power is important, it is a property that exists
in an absolute sense, detached from the application-specific context within
which an access control scheme will ultimately be deployed. In this paper, by
contrast, we formalize the access control suitability analysis problem, which
seeks to evaluate the degree to which a set of candidate access control schemes
can meet the needs of an application-specific workload. This process involves
both reductions to assess whether a scheme is capable of implementing a
workload, as well as cost analysis using ordered measures to quantify the
overheads of using each candidate scheme to service the workload. We develop a
mathematical framework for analyzing instances of the suitability analysis
problem, and evaluate this framework both formally (by quantifying its
efficiency and accuracy properties) and practically (by exploring a group-based
messaging workload from the literature). An ancillary contribution of our work
is the identification of auxiliary machines, which are a useful class of
modifications that can be made to enhance the expressive power of an access
control scheme without negatively impacting the safety properties of the
scheme.
