This is an extended version of the previous paper (hep-th/0701272). Quantum
fields near horizons can be described in terms of an infinite set of
two-dimensional conformal fields. We first generalize the method of Christensen
and Fulling to charged black holes to derive fluxes of energy and charge. These
fluxes can be obtained by employing a conformal field theory technique. We then
apply this technique to obtain the fluxes of higher-spin currents and show that
the thermal distribution of Hawking radiation from a charged black hole can be
completely reproduced by investigating transformation properties of the
higher-spin currents under conformal and gauge transformations.Comment: 15 page