  Nontrivial diffeomorphisms act on the horizon of a generic 4D black holes and
create distinguishing features referred to as soft hair. Amongst these are a
left-right pair of Virasoro algebras with associated charges that reproduce the
Bekenstein-Hawking entropy for Kerr black holes. In this paper we show that if
one adds a negative cosmological constant, there is a similar set of
infinitesimal diffeomorphisms that act non-trivially on the horizon. The
algebra of these diffeomorphisms gives rise to a central charge. Adding a
boundary counterterm, justified to achieve integrability, leads to well-defined
central charges with cL = cR. The macroscopic area law for Kerr-AdS black holes
follows from the assumption of a Cardy formula governing the black hole
microstates.
