  We consider possible superfield representations of extended BRST symmetry for
general gauge theories within the principle of gauge-fixing based on a
generating equation for the gauge functional. We examine admissible superfield
choices for an extended antibracket and delta-operator with given algebraic
properties and show that only one of these choices is compatible with the
requirement of extended BRST symmetry realized in terms of supertranslations
along Grassmann coordinates. We demonstrate that this realization leads to the
gauge-independence of the S-matrix.
