In Constroid, authorisations (A) are functional predicates
which have to be evaluated for usage decisions. They are
used to decide whether a subject is allowed to perform the
request operations on an object, i.e. whether it is privileged
to obtain the appropriate rights for an object. UCON distinguishes pre authorisation (A) or
ongoing authorisations(onA). Apart from preA, Constroid also allows for to
support policies which contain temporal or constraints.