  We investigate a-priori detection probabilities of genuine multipartite
entanglement (GME). Even if one does not have knowledge about the basis in
which a state is produced by a source, how a channel decoheres it or about the
very working of the detectors used, we find that it is possible to detect GME
with reasonably high probability in a feasible fashion. We show that by means
of certain separability criteria, GME can be detected in a
measurement-device-independent way. Our method provides several applications
whenever e.g. state tomography is not possible or too demanding, and is a tool
to investigate security issues in multi-particle quantum cryptographical
protocols.
