Finite quantum electrodynamics and gauge invariance

It was shown in a previous paper that the divergent radiative corrections of conventional QED become finite when calculated with a modified, smeared Feynman propagator. The smearing of the propagator can be interpreted as a smearing of the light cone over a distance of about a Planck length, caused by quantum fluctuations in the geometry. To achieve gauge invariance, a further modification of conventional QED is proposed involving the insertion of an extra form factor into the electron-photon vertex. The form factor corresponds to an extended charge distribution, with a size of about one Planck length and a mass of about one Planck mass.