  Gauge-invariance is a fundamental concept in Physics -- known to provide
mathematical justification for the fundamental forces. In this paper, we
provide discrete counterparts to the main gauge theoretical concepts directly
in terms of Cellular Automata. More precisely, the notions of gauge-invariance
and gauge-equivalence in Cellular Automata are formalized. A step-by-step
gauging procedure to enforce this symmetry upon a given Cellular Automaton is
developed, and three examples of gauge-invariant Cellular Automata are
examined.
