Both of these! And spot on with (mutual) motive analysis to come up
with an "alignment" matrix.
I was inspired some time ago by Stella Rimington's writing (ex MI5
chief) that "identity" is actually a very poor basis for trust and
authentication. It's unnerving watching the whole zero-trust show
organise itself around notions of strong identity (as opposed to role
and earned trust), which might turn out to be a rather silly thing to
do.
"Knowledge of origin creates trust. Knowledge of capabilities creates trust."
I'd add "a mental model of someone's motives creates trust".