Logics for Insecure Communication

We present a general setting for dynarnlc-epistemic logics for communication, which can express announcements of different types (public or private, truthful or not, reliable or not, secure or not etc.), queries of the corresponding types, complex dialogues, dialogue games, strategies (protocols) for communication etc. We analyze some examples, we discuss various properties of dialogues (normalcy, responsiveness, publicity, truthfulness, appropriateness of questions) which usually are tacitly assumed, and we formally define interesting types of dialogue which break these assumptions (rhetorical questions, eheatihg questions, Socratic dialogues, cheating by impersonation). We give an algorithm for computing the beliefs of the agents at the output-states, given their beliefs at the input-state and the the dynamic-epistemic features of the communication act. In the full paper, we give a complete and decidable axiom-system for each such logic.