We deduce the constraint structure and subsequently quantize a free-particle system residing on a torus satisfying the geometric constraint (r − a) = 0, within the framework of the modified Faddeev-Jackiw formalism. Further, we reformulate the system as a gauge theory by means of the symplectic gauge-invariant formalism. Finally, we establish the off-shell nilpotent and absolutely anti-commuting (anti-)BRST symmetries of the reformulated gauge-invariant theory.