  We show that the scotogenic dark symmetry can be obtained as a residual
subgroup of the global $U(1)_{B-L}$ symmetry already present in Standard Model.
We propose a general framework where the $U(1)_{B-L}$ symmetry is spontaneously
broken to an even $\mathcal{Z}_{2n}$ subgroup, setting the general conditions
for neutrinos to be Majorana and the dark matter stability in terms of the
residual $\mathcal{Z}_{2n}$. Under this general framework, as examples, we
build a class of simple models where, in the scotogenic spirit, the dark matter
candidate is the lightest particle running inside the neutrino mass loop. The
global $U(1)_{B-L}$ symmetry in our framework being anomaly free can also be
gauged in a straightforward manner leading to a richer phenomenology.
