Radiation shielding

Passive mass, electromagnetic, combination of those, or some other
technology?

If passive mass, will it be in its original form (i.e. dig out the
inside of an asteroid and live there) or will it be re-worked (e.g.
make basalt-fiber to bear the tension around the outside of a rotating
habitat, and have that be a major component of the mass shield)? Will
the shield rotate with the habitat, and have to bear its own
centrifugal weight? Or will it be separate, and have to have something
like an axle and bearings?