  Secret neutrino interactions can play an essential role in the origin of dark
matter. We present an anatomy of production mechanisms for sterile neutrino
dark matter, a keV-scale gauge-singlet fermion that mixes with active
neutrinos, in the presence of a new vector boson mediating secret interactions
among active neutrinos. We identify three regimes of the vector boson's mass
and coupling where it makes distinct impact on dark matter production through
the dispersion relations and/or scattering rates. We also analyze models with
gauged $L_\mu-L_\tau$ and $B-L$ numbers which have a similar dark matter
cosmology but different vector boson phenomenology. We derive the parameter
space in these models where the observed relic abundance is produced for
sterile neutrino dark matter. They serve as well-motivated target for the
upcoming experimental searches.
