  In this paper we propose a number of KEM-based protocols to establish a
shared secret between two parties, and study their resistance over
unauthenticated channels. This means analyzing the security of the protocol
itself, and its robustness against Man-in-the-Middle attacks. We do this by
constructing a variation of known unauthenticated models that applies the
techniques used to constructed the protocols, and formalize their security
under this model. We compare them with their KEX-based counterparts to
highlight the differences that arise naturally, due to the nature of KEM
constructions, in terms of the protocol itself and the types of attacks that
they are subject to. We provide practical go-to KEM-based protocols instances
to migrate to, based on the conditions of currently-in-use KEX-based protocols.
