  We compute---at finite quark chemical potentials---the color screening of
cold quark matter at the one-loop level, comparing the normal, BCS-paired
U(1)em (or Higgs) phase and a singlet phase with color-singlet condensate near
the Fermi surface. The latter phase is computed using the example of two-color
QCD with a color-singlet diquark condensate. In contrast to the normal and
Higgs phases, neither electric nor magnetic screening masses appear in the
singlet phase. The absence of a magnetic mass, within a perturbative framework,
is a consequence of the proper treatment of gauge invariance. While at large
momenta the gluon self-energies approach those in the normal phase, the medium
contributions to the infrared region below a scale of the mass gap are
substantially suppressed. Infrared gluons at low quark density in the singlet
phase appear protected from medium effects, unless the quark-gluon vertices are
significantly enhanced in the infrared.
