Anyone can publish a nanopublication, and anyone can publish one claiming to be somebody. A signature proves that a nanopublication was made with a particular key, but not whose key that is. The network therefore keeps a trust state: the set of keys it accepts as belonging to the people and agents they claim to belong to. Everything that depends on \"who published this\" — space membership, roles, retractions, member-only content — is answered from that state.