Magnetic fields at extragalactic scales: origin from the early universe?

Blazar observations have provided tantalizing evidence for the presence of magnetic fields in the extragalactic regions, where astrophysical processes may not be an efficient source for their generation. While a natural speculation is to associate the production of such large-scale magnetic fields to inflationary physics, it has been known that magnetogenesis solely from inflation is quite challenging. In this talk I will discuss some mechanisms, successful/unsuccessful, for production of magnetic fields in the primordial universe, as well as the constraints from theoretical consistencies and observational data.