On automorphisms of C*-algebras associated with subshifts

We prove that, for a given one-sided subshift X-Lambda, any non-trivial automorphism of the subshift always yields an outer automorphism of the C*-algebra O-Lambda associated with the subshift. In particular, any non-trivial automorphism of the one-sided topological Markov shift X-A for a {0, 1}-matrix A yields an outer automorphism of the Cuntz-Krieger algebra O-A. We also determine the form of the automorphisms of the C*-algebra O-Lambda arising from automorphisms of the subshift X-A.