  In order to preserve the privacy of the users demands from other users, in
this paper we formulate a novel information theoretic Device-to-Device (D2D)
private caching model by adding a trusted server. In the delivery phase, the
trusted server collects the users demands and sends a query to each user, who
then broadcasts packets according to this query. Two D2D private caching
schemes (uncoded and coded) are proposed in this paper, which are shown to be
order optimal.
