  In recent years, several combinatorial problems were introduced in the area
of access control. Typically, such problems deal with an authorization policy,
seen as a relation $UR \subseteq U \times R$, where $(u, r) \in UR$ means that
user $u$ is authorized to access resource $r$. Li, Tripunitara and Wang (2009)
introduced the Resiliency Checking Problem (RCP), in which we are given an
authorization policy, a subset of resources $P \subseteq R$, as well as
integers $s \ge 0$, $d \ge 1$ and $t \geq 1$. It asks whether upon removal of
any set of at most $s$ users, there still exist $d$ pairwise disjoint sets of
at most $t$ users such that each set has collectively access to all resources
in $P$. This problem possesses several parameters which appear to take small
values in practice. We thus analyze the parameterized complexity of RCP with
respect to these parameters, by considering all possible combinations of $|P|,
s, d, t$. In all but one case, we are able to settle whether the problem is in
FPT, XP, W[2]-hard, para-NP-hard or para-coNP-hard. We also consider the
restricted case where $s=0$ for which we determine the complexity for all
possible combinations of the parameters.
