  In multi-agent planning, agents jointly compute a plan that achieves mutual
goals, keeping certain information private to the individual agents. Agents'
coordination is achieved through the transmission of messages. These messages
can be a source of privacy leakage as they can permit a malicious agent to
collect information about other agents' actions and search states. In this
paper, we investigate the usage of novelty techniques in the context of
(decentralised) multi-agent privacy-preserving planning, addressing the
challenges related to the agents' privacy and performance. In particular, we
show that the use of novelty based techniques can significantly reduce the
number of messages transmitted among agents, better preserving their privacy
and improving their performance. An experimental study analyses the
effectiveness of our techniques and compares them with the state-of-the-art.
Finally, we evaluate the robustness of our approach, considering different
delays in the transmission of messages as they would occur in overloaded
networks, due for example to massive attacks or critical situations.
