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 onA to
support policies which contain temporal or spacial constraints.