  Recently it has been shown that quantum cryptography beyond pure entanglement
distillation is possible and a paradigm for the associated protocols has been
established. Here we systematically generalize the whole paradigm to the
multipartite scenario. We provide constructions of new classes of multipartite
bound entangled states, i.e., those with underlying twisted GHZ structure and
nonzero distillable cryptographic key. We quantitatively estimate the key from
below with help of the privacy squeezing technique.
