Multi Party System with n-1 adversaries Novice here. Is there a MPC function where no information is leaked even if all parties are not trustworthy ?
Yes there  are. The search term you are looking for is either "dishonest majority" (which doesn't necessarily mean n-1, but often that is the case) or "full-threshold". The SPDZ protocol is one that works in the malicious model that would meet your description.