Communication and mobility control in boxed ambients

Boxed Ambients (BA) replace Mobile Ambients’ open capability with communication primitives acting across ambient boundaries. The expressiveness of the new model of communication is achieved at the price of interferences that affect message reception and whose resolution requires synchronisation of activities at multiple, distributed locations. We study a variant of BA aimed at controlling communication interferences as well as mobility ones. Our calculus modifies the communication mechanism of BA, and introduces a new form of co-capability, inspired from Safe Ambients (SA) (with passwords), that registers incoming agents with the receiver ambient while at the same time performing access control. We prove that new calculus has a rich semantics theory, including a sound and complete coinductive characterisation, and an expressive, yet simple type system. Through a set of examples, and an encoding, we characterise its expressiveness with respect to both BA and SA.