An improved two-party negotiation over continues issues method secure against manipulatory behavior

This contribution focuses on two-party negotiation over continuous issues. We firstly prove two drawbacks of the jointly Improving Direction Method (IDM), namely that IDM is not a Strategy-Proof (SP) nor an Information Concealing (IC) method. Thus we prove that the concurrent lack of these two properties implies the actual non- efficiency of IDM. Finally we propose a probabilistic method which is both IC and stochastically SP thus leading to efficient settlements without being affected by manipulatory behaviors.