  Inspired by recent developments in the study of chaos in many-body systems,
we construct a measure of local information spreading for a stochastic Cellular
Automaton in the form of a spatiotemporally resolved Hamming distance. This
decorrelator is a classical version of an Out-of-Time-Order Correlator studied
in the context of quantum many-body systems. Focusing on the one-dimensional
Kauffman Cellular Automaton, we extract the scaling form of our decorrelator
with an associated butterfly velocity $v_b$ and a velocity-dependent Lyapunov
exponent $\lambda(v)$. The existence of the latter is not a given in a discrete
classical system. Second, we account for the behaviour of the decorrelator in a
framework based solely on the boundary of the information spreading, including
an effective boundary random walk model yielding the full functional form of
the decorrelator. In particular, we obtain analytic results for $v_b$ and the
exponent $\beta$ in the scaling ansatz $\lambda(v) \sim \mu (v - v_b)^\beta$,
which is usually only obtained numerically. Finally, a full scaling collapse
establishes the decorrelator as a unifying diagnostic of information spreading.
