  We explore the generation of the baryon asymmetry in an extension of the
Standard Model where the lepton number is promoted to a $U(1)_\ell$ gauge
symmetry with an associated $Z^\prime$ gauge boson. This is based on a novel
electroweak baryogenesis mechanism first proposed by us in Ref.
\cite{Carena:2018cjh}. Extra fermionic degrees of freedom - including a
fermionic dark matter $\chi$ - are introduced in the dark sector for anomaly
cancellation. Lepton number is spontaneously broken at high scale and the
effective theory, containing the Standard Model, the $Z^\prime$, the fermionic
dark matter, and an additional complex scalar field $S$, violates CP in the
dark sector. The complex scalar field couples to the Higgs portal and is
essential in enabling a strong first order phase transition. Dark CP violation
is diffused in front of the bubble walls and creates a chiral asymmetry for
$\chi$, which in turn creates a chemical potential for the Standard Model
leptons. Weak sphalerons are then in charge of transforming the net lepton
charge asymmetry into net baryon number. We explore the model phenomenology
related to the leptophilic $Z^\prime$, the dark matter candidate, the Higgs
boson and the additional scalar, as well as implications for electric dipole
moments. We also discuss the case when baryon number $U(1)_B$ is promoted to a
gauge symmetry, and discuss electroweak baryogenesis and its corresponding
phenomenology.
